JP2007207413A - Semiconductor device, display device provided with semiconductor device, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device where characteristic deterioration of each transistor is suppressed without making operation instable. <P>SOLUTION: In a non-selection period, turning on of a transistor every fixed interval supplies power source potential to the output terminal of a shift register circuit. The output terminal of the shift register circuit is supplied with the power source potential through the transistor. Since the transistor is not on constantly in the non-selection period, the shift of the threshold potential of the transistor is suppressed. The output terminal of the shift register circuit is supplied with the power source potential every fixed interval through the transistor. Thus, the shift register circuit suppresses occurrence of noise in the output terminal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a semiconductor device. In particular, the present invention relates to a shift register including transistors. In addition, the present invention relates to a display device including a semiconductor device and an electronic device including the display device.

In recent years, display devices such as liquid crystal display devices and light-emitting devices have been actively developed due to an increase in large display devices such as liquid crystal televisions. In particular, a technology in which a driver circuit including a pixel circuit and a shift register circuit (hereinafter referred to as an internal circuit) is integrally formed using a transistor formed of an amorphous semiconductor over an insulator has low power consumption and low cost. In order to make a significant contribution to the development, development is actively underway. An internal circuit formed on the insulator is connected to a controller IC or the like (hereinafter referred to as an external circuit) disposed outside the insulator via an FPC or the like, and its operation is controlled.

As an internal circuit integrally formed on an insulator, a shift register circuit using an amorphous semiconductor transistor has been devised (see Patent Document 1).

However, since the shift register circuit has a period during which the output terminal is in a floating state, noise is likely to occur at the output terminal. The shift register circuit malfunctioned due to noise generated at the output terminal.

In order to solve the above problem, a shift register circuit has been devised in which an output terminal does not enter a floating state. This shift register circuit operates by so-called static driving (see Patent Document 2).

The shift register circuit shown in Patent Document 2 enables static driving. Therefore, this shift register circuit can reduce noise generated at the output terminal because the output terminal does not enter a floating state.
International Publication No. 95/31804 Pamphlet JP 2004-78172 A

In the above-described shift register circuit shown in Patent Document 2, the operation period is divided into a selection period in which one selection signal is output and a non-selection period in which a non-selection signal is output. It becomes a non-selection period. In the non-selection period, a low potential is supplied to the output terminal via the transistor. That is, the transistor for supplying a low potential to the output terminal is on during most of the operation period of the shift register circuit.

It is known that the characteristics of a transistor manufactured using an amorphous semiconductor are deteriorated in accordance with a turn-on time and an applied potential. In particular, a threshold potential shift in which the threshold potential of a transistor rises is prominent when transistor characteristics deteriorate. This threshold potential shift is one of the major causes of malfunction of the shift register circuit.

In view of such problems, in the present invention, a shift register circuit that can reduce noise and suppress deterioration of a transistor even in a non-selection period, a semiconductor device or a display device including the shift register circuit, or the display device is provided. An object is to provide an electronic device provided.

The present invention is characterized in that a transistor included in a semiconductor device is not always turned on and deterioration of characteristics of the transistor is suppressed.

One of the semiconductor devices of the present invention includes a first transistor, a second transistor, a third transistor, an inverter, a first wiring, a second wiring, and a third wiring. The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the inverter. The second transistor is electrically connected to the first terminal, the first terminal is electrically connected to the second wiring, and the gate terminal is electrically connected to the second terminal of the third transistor. The third transistor has a first terminal electrically connected to the third wiring, a gate terminal electrically connected to the second terminal of the inverter, and a gate terminal of the first transistor being , Make the gate terminal floating Characterized in that it is electrically connected in order of the transistor.

One embodiment of a semiconductor device of the present invention includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first wiring, and a second wiring. , A third wiring, and a fourth wiring. The first transistor has a first terminal electrically connected to the first wiring and a second terminal connected to the second transistor. The second terminal is electrically connected to the second wiring, the gate terminal is electrically connected to the gate terminal of the fourth transistor, the first transistor is electrically connected to the second wiring, The gate terminal is electrically connected to the second terminal of the third transistor, the third transistor is electrically connected to the third wiring, and the gate terminal is electrically connected to the fourth transistor. The second terminal and the fifth transformer The fourth transistor is electrically connected to the second wiring, and the fifth transistor has the first terminal connected to the fourth terminal. Electrically connected to a wiring, a gate terminal is electrically connected to the fourth wiring, and a gate terminal of the first transistor is electrically connected to a transistor for bringing the gate terminal into a floating state. It is characterized by.

One embodiment of a semiconductor device of the present invention includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, and a first wiring. , Having a second wiring, a third wiring, a fourth wiring, and a fifth wiring, wherein the first transistor has a first terminal electrically connected to the first wiring. The second terminal is electrically connected to the second terminal of the second transistor, the gate terminal is electrically connected to the gate terminal of the fourth transistor, and the second terminal of the sixth transistor; The second transistor has a first terminal electrically connected to the second wiring, a gate terminal electrically connected to a second terminal of the third transistor, and the third transistor having a first terminal One terminal is electrically connected to the third wiring And the gate terminal is electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor, and the fourth transistor is electrically connected to the second wiring. And the fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring, and the sixth transistor including: The first terminal is electrically connected to the fourth transistor, and the gate terminal is electrically connected to the fifth wiring.

One embodiment of a semiconductor device of the present invention includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, and a seventh transistor. , First wiring, second wiring, third wiring, fourth wiring, and fifth wiring, wherein the first transistor has a first terminal connected to the first wiring. The second terminal is electrically connected to the second terminal of the second transistor, the gate terminal is the gate terminal of the fourth transistor, the second terminal of the sixth transistor, and The seventh transistor is electrically connected to the second terminal of the seventh transistor, and the second transistor has a first terminal electrically connected to the second wiring and a gate terminal connected to the second terminal of the third transistor. Terminal and the seventh transistor The third transistor is electrically connected to the third wiring, the gate terminal is electrically connected to the second terminal of the fourth transistor, and the fifth transistor is electrically connected to the gate terminal of the fourth transistor. The fourth transistor is electrically connected to the second wiring, and the fifth transistor has the first terminal connected to the second terminal of the fourth transistor. The gate terminal is electrically connected to the fourth wiring, the sixth transistor has the first terminal electrically connected to the fourth transistor, and the gate terminal The seventh transistor is electrically connected to the fifth wiring, and the seventh transistor has a first terminal electrically connected to the second wiring.

One embodiment of a semiconductor device of the present invention includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, and a seventh transistor. , Having an eighth transistor, a first wiring, a second wiring, a third wiring, a fourth wiring, a fifth wiring, and a sixth wiring, the first transistor The first terminal is electrically connected to the first wiring, the second terminal is electrically connected to the second terminal of the second transistor, the gate terminal is the gate terminal of the fourth transistor, The second transistor is electrically connected to the second terminal of the sixth transistor, the second terminal of the seventh transistor, and the second terminal of the eighth transistor, and the second terminal of the second transistor is the first terminal of the sixth transistor. 2 is electrically connected to A first terminal is electrically connected to a second terminal of the third transistor and a gate terminal of the seventh transistor, and the third terminal of the third transistor is electrically connected to the third wiring. And the gate terminal is electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor, and the fourth transistor is electrically connected to the second wiring. And the fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring, and the sixth transistor including: The first terminal is electrically connected to the fourth transistor, the gate terminal is electrically connected to the fifth wiring, and the seventh transistor has the first terminal electrically connected to the second wiring. Connected to the Njisuta has a first terminal electrically connected to the second wiring, the gate terminal is characterized in that it is electrically connected to the sixth wiring.

In the present invention, the ratio W / L of the channel length L to the channel width W of the fourth transistor is not less than 10 times the ratio W / L of the channel length L to the channel width W of the fifth transistor. May be.

In the present invention, the first transistor and the third transistor may have the same conductivity type.

In the present invention, the first transistor and the fourth transistor may be N-channel type or P-channel type.

In the present invention, a capacitive element electrically connected between the second terminal and the gate terminal of the first transistor may be provided.

In the present invention, a capacitor may be formed using a MOS transistor instead of the capacitor.

In the present invention, the capacitor element includes a first electrode, a second electrode, and an insulator sandwiched between the first electrode and the second electrode, and the first electrode It may be a semiconductor layer, the second electrode may be a gate wiring layer, and the insulator may be a gate insulating film.

In the present invention, a clock signal may be supplied to the first wiring, and an inverted clock signal having a phase that is 180 degrees different from the clock signal may be supplied to the third wiring.

One embodiment of the display device of the present invention is a display device including a plurality of pixels and a driver circuit, wherein the pixels are controlled by the driver circuit, and the driver circuit constantly turns on the plurality of transistors and the transistors. And a circuit for preventing the above.

In the present invention, the driver circuit may include the semiconductor device described above.

In the present invention, the pixel includes at least one transistor, and the transistor included in the pixel and the transistor included in the driver circuit may have the same conductivity type.

In the present invention, the pixel may be formed on the same substrate as the driving circuit.

The display device of the present invention may be applied to an electronic device.

As described above, according to the present invention, in order to prevent the second transistor and the seventh transistor from being always turned on, the second transistor and the second transistor are controlled by a signal supplied to the third wiring. 7 is used to control ON or OFF of the transistor 7.

Further, by connecting the gate terminal of the first transistor to the gate terminal of the second transistor via an inverter so that the second transistor is not turned on when the first transistor is turned on. The third transistor is turned off. If the second transistor is turned off before the third transistor is turned off, the second transistor is continuously turned off. Therefore, the first wiring and the second wiring are not conducted through the first transistor and the second transistor.

Note that if the potential of the first wiring changes when the first transistor is on and the second transistor is off, the potential of the second terminal of the first transistor also changes. To do. At this time, if the gate terminal of the first transistor is in a floating state, the potential of the gate terminal of the first transistor changes simultaneously due to capacitive coupling of the capacitive element. Here, if the potential of the gate terminal of the first transistor changes to a value greater than or less than the sum of the potential of the first wiring and the threshold potential of the first transistor, the first transistor The transistor of this continues to turn on. As described above, even when the potential of the first wiring changes, the first transistor is turned on, and the first terminal and the second terminal of the first transistor have a function of the same potential.

Note that an electrical switch or a mechanical switch can be used as the switch described in the specification, for example. That is, it is only necessary to be able to control the current flow, and is not limited to a specific one. It may be a transistor, a diode (PN diode, PIN diode, Schottky diode, diode-connected transistor, or the like), or a logic circuit that is a combination thereof. Therefore, when a transistor is used as a switch, the transistor operates as a mere switch, and thus the polarity (conductivity type) of the transistor is not particularly limited. However, when it is desirable that the off-state current is small, it is desirable to use a transistor having a polarity with a small off-state current. As a transistor with low off-state current, there are a transistor provided with an LDD region and a transistor having a multi-gate structure. In addition, when the potential of the source terminal of the transistor that operates as a switch is close to the low potential side power supply (Vss, GND, 0 V, etc.), the N channel type is used. In the case of a state close to (such as Vdd), it is desirable to use a P-channel type. This is because the absolute value of the voltage between the gate and the source can be increased, so that it is easy to operate when functioning as a switch. Note that both N-channel and P-channel switches may be used as CMOS switches.

In the present invention, being connected is synonymous with being electrically connected. Therefore, another element, a switch, or the like may be disposed between them.

Note that a display element, a display device that is a device including a display element, a light-emitting element, and a light-emitting device that is a device including a light-emitting element can have various modes or have various elements. For example, a display medium whose contrast is changed by an electromagnetic action, such as an EL element (an organic EL element, an inorganic EL element, or an EL element including an organic substance and an inorganic substance), an electron-emitting element, a liquid crystal element, and electronic ink can be used. . Note that an EL display is used as a display device using an EL element, and a liquid crystal display such as a field emission display (FED) or an SED type flat display (SED: Surface-Conduction Electron-Emitter Display) is used as a display device using an electron-emitting device. There is a liquid crystal display as a display device using an element, and an electronic paper as a display device using electronic ink.

Note that there is no limitation on the types of transistors that can be used in the present invention, and the transistor is formed using a thin film transistor (TFT) using a non-single-crystal semiconductor film typified by amorphous silicon or polycrystalline silicon, a semiconductor substrate, or an SOI substrate. Transistors, MOS transistors, junction transistors, bipolar transistors, transistors using compound semiconductors such as ZnO and a-InGaZnO, transistors using organic semiconductors and carbon nanotubes, and other transistors can be applied. There is no limitation on the kind of the substrate over which the transistor is provided, and the transistor can be provided on a single crystal substrate, an SOI substrate, a glass substrate, a plastic substrate, or the like.

Note that as described above, the transistor in the present invention may be any type of transistor, and may be formed on any substrate. Therefore, the entire circuit may be formed on a glass substrate, may be formed on a plastic substrate, may be formed on a single crystal substrate, or may be formed on an SOI substrate. However, it may be formed on any substrate. Alternatively, a part of the circuit may be formed on a certain substrate, and another part of the circuit may be formed on another substrate. That is, all of the circuits may not be formed on the same substrate. For example, part of a circuit is formed using a transistor over a glass substrate, another part of the circuit is formed over a single crystal substrate, and the IC chip is connected with COG (Chip On Glass) to form a glass. You may arrange | position on a board | substrate. Alternatively, the IC chip may be connected to the glass substrate using TAB (Tape Automated Bonding) or a printed board.

Note that there is no particular limitation on the structure of the transistor. For example, a multi-gate structure in which the number of gates is two or more may be employed, a gate electrode may be disposed above and below the channel, or a gate electrode may be disposed on the channel. It may be a structure, a structure in which a gate electrode is disposed under a channel, a normal staggered structure, an inverted staggered structure, or a channel region may be divided into a plurality of regions. In addition, they may be connected in parallel, may be connected in series, a channel (or part thereof) may overlap with a source electrode or a drain electrode, or may have an LDD region. .

In this specification, one pixel represents the minimum unit of an image. Therefore, in the case of a full-color display device composed of R (red), G (green), and B (blue) color elements, one pixel is a dot of the R color element, a dot of the G color element, and a B color element. It shall be composed of dots.

Note that in this specification, the pixels are arranged in a matrix, not only in the case of a so-called grid pattern in which vertical stripes and horizontal stripes are combined, but also in full-color display with three color elements (for example, RGB). When performing the above, the case where the dots of the three color elements are arranged in a so-called delta arrangement is also included. In addition, the size of the light emitting area may be different for each dot of the color element.

A transistor is an element having at least three terminals including a gate electrode, a drain region, and a source region, and has a channel formation region between the drain region and the source region. Here, since the source region and the drain region vary depending on the structure and operating conditions of the transistor, it is difficult to limit which is the source region or the drain region. Therefore, in this specification, regions functioning as a source region and a drain region are referred to as a first terminal and a second terminal, respectively.

Note that in this specification, a semiconductor device refers to a device having a circuit including a semiconductor element (such as a transistor or a diode). In addition, any device that can function by utilizing semiconductor characteristics may be used. The display device is not only a display panel body in which a plurality of pixels including a display element such as a liquid crystal element or an EL element on a substrate and a peripheral drive circuit for driving these pixels are formed, but also a flexible printed circuit ( FPC) and a printed wiring board (PWB) attached are also included. A light-emitting device refers to a display device using a self-luminous display element such as an EL element or an element used in an FED.

In the semiconductor device of the present invention, a transistor whose on / off state is controlled by a signal supplied to the third wiring can be turned on at regular intervals. Thus, since the transistor of the shift register circuit using the semiconductor device of the present invention is not always turned on in the non-selection period, shift of the threshold potential of the transistor can be suppressed. In addition, a power supply potential is supplied to the output terminal of the shift register circuit using the semiconductor device of the present invention at regular intervals through the transistor. Therefore, the shift register circuit using the semiconductor device of the present invention can suppress noise generated at the output terminal.

Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of the embodiments and examples.

(Embodiment 1)
FIG. 1 shows one mode of a flip-flop circuit 10 included in the shift register circuit of the present invention. The shift register circuit of the present invention has a plurality of flip-flop circuits 10. The flip-flop circuit 10 illustrated in FIG. 1 includes a transistor 11, a transistor 12, a transistor 13, a transistor 14, a transistor 15, a transistor 16, a transistor 17, a transistor 18, and a capacitor 19 having two electrodes. However, the capacitive element 19 is not necessarily required when the gate capacitance of the transistor 12 can be substituted.

As shown in the flip-flop circuit 10, the gate terminal of the transistor 11 is connected to the input terminal IN 1, the first terminal is connected to the first power supply, the second terminal is the gate terminal of the transistor 12, and the second terminal of the transistor 14. To the gate terminal of the transistor 15, the second terminal of the transistor 17, and the second electrode of the capacitor 19. The first terminal of the transistor 15 is connected to the second power supply, and the second terminal is connected to the second terminal of the transistor 16 and the gate terminal of the transistor 18. The gate terminal and the first terminal of the transistor 16 are connected to the first power supply. A first terminal of the transistor 18 is connected to the input terminal IN 3, and a second terminal is connected to the gate terminal of the transistor 13 and the gate terminal of the transistor 14. The first terminal of the transistor 13 is connected to the second power supply, and the second terminal is connected to the first electrode of the capacitor 19, the second terminal of the transistor 12, and the output terminal OUT. A first terminal of the transistor 12 is connected to the input terminal IN2. The first terminal of the transistor 14 is connected to the second power source. The gate terminal of the transistor 17 is connected to the input terminal IN4, and the first terminal is connected to the second power source.

Note that in the flip-flop circuit 10, the second terminal of the transistor 11, the gate terminal of the transistor 12, the second terminal of the transistor 14, the gate terminal of the transistor 15, the second terminal of the transistor 17, and the second electrode of the capacitor 19 Let the node be N1. A node of the second terminal of the transistor 15 and the second terminal of the transistor 16 is N2. A node of the gate terminal of the transistor 13, the gate terminal of the transistor 14, and the second terminal of the transistor 18 is N3.

In addition, the power supply potential VDD is supplied to the first power supply, and the power supply potential VSS is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VDD of the first power supply and the power supply potential VSS of the second power supply corresponds to the power supply voltage of the flip-flop circuit 10. The power supply potential VDD is higher than the power supply potential VSS.

Control signals are supplied to the input terminals IN1 to IN4, respectively. The output terminal OUT outputs an output signal. The output signal of the previous flip-flop circuit 10 is supplied as a control signal to the input terminal IN1. The output signal of the flip-flop circuit 10 at the next stage is supplied as a control signal to the input terminal IN4.

The transistors 11 to 18 are each an N-channel type. However, the transistors 11 to 18 may each be a P-channel type.

Next, the operation of the flip-flop circuit 10 shown in FIG. 1 will be described using the timing chart shown in FIG. FIG. 2 shows a timing chart of the control signals supplied to the input terminals IN1 to IN4 shown in FIG. 1, the output signals output from the output terminals OUT, and the potentials of the nodes N1 to N3. . Further, the timing chart shown in FIG. 2 is divided into periods T1 to T4 for convenience.

Note that the period T3 and the period T4 are sequentially repeated in the period after the period T4. In FIG. 2, the period T1 is defined as a selection preparation period, the period T2 is defined as a selection period, and the periods T3 and T4 are defined as non-selection periods. That is, one selection preparation period, one selection period, and a plurality of non-selection periods are repeated in order.

In the timing chart shown in FIG. 2, the control signal and the output signal have binary values. That is, these signals are digital signals, and the potential of these digital signals is VDD (hereinafter also referred to as potential VDD or H level) which is the same potential as the power supply potential of the first power supply when it is an H signal. , The L signal is VSS which is the same potential as the power supply potential of the second power supply (hereinafter also referred to as potential VSS or L level).

3 to 6 show the flip-flop circuit 10 corresponding to the operations in the periods T1 to T4, respectively.

3 to 6 show that the transistor indicated by the solid line is on. It shows that the transistor indicated by the broken line is off. Wiring indicated by a solid line indicates that it is connected to a power supply or an input terminal. This indicates that the wiring indicated by the broken line is not connected to the power source or the input terminal.

Next, the operation | movement for every period is demonstrated using FIGS.

First, operation of the flip-flop circuit 10 in the period T1 is described with reference to FIG. FIG. 3 is a diagram illustrating a connection state of the flip-flop circuit 10 in the period T1.

In the period T1, the input terminal IN1 is at an H level, and the transistor 11 is turned on. The input terminal IN4 becomes L level, and the transistor 17 is turned off. Since the node N3 maintains VSS obtained in a period T3 described later, the transistor 14 is turned off. The node N1 is electrically connected to the first power supply through the transistor 11, and the potential of the node N1 rises to Vn11. When the node N1 becomes Vn11, the transistor 11 is turned off. Here, Vn11 is a value obtained by subtracting the threshold potential Vth11 of the transistor 11 from the power supply potential VDD (VDD−Vth11). Note that Vn11 is a potential at which the transistor 12 and the transistor 15 can be turned on.

The potential of the node N1 becomes Vn11, the transistor 11 is turned off, and the transistors 12 and 15 are turned on. The node N2 is electrically connected to the second power supply via the transistor 15, and is electrically connected to the first power supply via the transistor 16, and the potential of the node N2 becomes Vn21. Here, Vn21 is determined by the operating point of the transistor 16 and the transistor 15. Note that the transistor 15 and the transistor 16 constitute an inverter using the two transistors. Therefore, when an H level signal is input to the gate terminal (node N1) of the transistor 15, an L level signal is input to the node N2. Here, Vn21 is a potential at which the transistor 18 can be turned off. Accordingly, even when the input terminal IN3 is at the H level, the transistor 18 is off, so that the node N3 can maintain VSS. The input terminal IN2 is at the L level, the output terminal OUT is electrically connected to the input terminal IN2 through the transistor 12, and the potential of the output terminal OUT becomes VSS.

Since the potential of the node N2 becomes Vn21 and the transistor 18 is turned off, the node N3 maintains VSS, and the transistors 13 and 14 are turned off.

With the above operation, in the period T1, the transistor 12 is turned on and the output terminal OUT is set to L level. Since the transistor 11 is off, the node N1 is in a floating state.

Next, operation of the flip-flop circuit 10 in the period T2 is described with reference to FIG. FIG. 4 is a diagram illustrating a connection state of the flip-flop circuit 10 in the period T2.

In the period T2, the input terminal IN1 is at the L level, and the transistor 11 is off. The input terminal IN4 remains at the L level, and the transistor 17 is off. Therefore, the node N1 is in a floating state following the period T1, and maintains the potential Vn11 of the period T1.

Since the potential of the node N1 is maintained at Vn11, the transistor 12 is turned on. Then, the input terminal IN2 becomes H level. Then, since the output terminal OUT is electrically connected to the input terminal IN2 through the transistor 12, the potential of the output terminal OUT rises from VSS. The potential of the node N1 changes to Vn12 due to capacitive coupling of the capacitive element 19, and the transistor 12 continues to be turned on. A so-called bootstrap operation is performed. As a result, the output terminal OUT rises to a potential equal to VDD that is the potential of the input terminal IN2. Note that Vn12 is a value equal to or higher than the sum of the potential VDD and the threshold potential Vth12 of the transistor 12.

Even when the potential of the node N1 becomes Vn12, the transistor 15 continues to be on. Therefore, the potential of the node N2 and the potential of the node N3 are the same as those in the period T1.

Through the above operation, in the period T2, the transistor 12 is kept on by raising the potential of the node N1 in the floating state by the bootstrap operation. Therefore, the potential of the output terminal OUT is set to VDD, and the output terminal OUT is set to H level.

Next, operation of the flip-flop circuit 10 in the period T3 is described with reference to FIG. FIG. 5 is a diagram illustrating a connection state of the flip-flop circuit 10 in the period T3.

In the period T3, the input terminal IN1 remains at the L level, and the transistor 11 is off. The input terminal IN4 becomes H level and the transistor 17 is turned on. Then, the node N1 becomes conductive with the second power supply via the transistor 17, and the potential of the node N1 becomes VSS.

The potential of the node N1 becomes VSS, and the transistor 12 and the transistor 15 are turned off. Since the node N2 is electrically connected to the first power supply via the transistor 16, the potential of the node N2 rises to Vn22. Here, Vn22 is a value obtained by subtracting the threshold potential Vth16 of the transistor 16 from the power supply potential VDD (VDD−Vth16). Note that Vn22 is a potential at which the transistor 18 can be turned on.

The potential of the node N2 becomes Vn22, and the transistor 18 is turned on. Since the input terminal IN3 is at the H level, the node N3 is electrically connected to the input terminal IN3 through the transistor 18, and the potential of the node N3 becomes Vn31. Here, Vn31 is a value obtained by subtracting the threshold potential Vth18 of the transistor 18 from the potential Vn22 of the node N2 (Vn22−Vth18). Note that Vn31 corresponds to a value (VDD−Vth16−Vth18) obtained by subtracting the threshold potential Vth16 of the transistor 16 and the threshold potential Vth18 of the transistor 18 from the power supply potential VDD. Vn31 is a potential at which the transistor 13 and the transistor 14 can be turned on.

The potential of the node N3 becomes Vn31, and the transistor 13 is turned on. Since the output terminal OUT is electrically connected to the second power supply via the transistor 13, the potential of the output terminal OUT becomes VSS.

Through the above operation, in the period T3, VSS is supplied to the node N1, and the transistors 12 and 15 are turned off. Further, the node N3 is set to the H level, and the transistor 13 and the transistor 14 are turned on. Therefore, the potential of the output terminal OUT is set to VSS, and the output terminal OUT is set to L level.

Next, operation of the flip-flop circuit 10 in the period T4 is described with reference to FIG. FIG. 6 is a diagram illustrating a connection state of the flip-flop circuit 10 in the period T4.

In the period T4, the input terminal IN3 is at the L level, and the potential of the node N3 is VSS. Therefore, the transistor 13 is turned off. The transistor 14 is also turned off. The input terminal IN4 becomes L level, and the transistor 17 is turned off. Then, the node N1 enters a floating state, and the potential of the node N1 maintains VSS.

Since the potential of the node N1 remains at VSS, the transistor 12 remains off and the transistor 15 also remains off. Therefore, the node N2 remains at Vn22, and the transistor 18 remains off.

Since the transistors 12 and 13 are turned off, the output terminal OUT is in a floating state. Therefore, the potential of the output terminal OUT is maintained at VSS.

Through the above operation, in the period T4, the potential of the output terminal OUT is maintained at VSS, so that the transistor 13 and the transistor 14 can be turned off. As described above, since the transistor 13 and the transistor 14 are not always turned on, deterioration in characteristics of the transistor 13 and the transistor 14 can be suppressed.

A relationship between the periods T1 to T4 will be described. The next period after the period T1 is the period T2, the next period after the period T2 is the period T3, and the next period after the period T3 is the period T4. Here, the period subsequent to the period T4 is the period T1 or the period T3. That is, the period following the period T4 is the period T1 when the input terminal IN1 is at the H level, and is the period T3 when the input terminal IN1 is at the L level. When the period T3 is a period subsequent to the period T4, the input terminal IN4 remains at the L level, and the transistor 17 remains off.

Here, functions of the transistors 11 to 18 and the capacitor 19 are described below.

The transistor 11 has a function as a switch for selecting whether or not to connect the first power supply and the node N1 in accordance with a control signal supplied to the input terminal IN1. In the period T1, the transistor 11 has a function of supplying the power supply potential VDD to the node N1 and turning off when the potential of the node N1 becomes Vn11.

The transistor 11 has a function of bringing the node N1 into a floating state (floating state) in accordance with a control signal supplied to the input terminal IN1. In the period T1 and the period T2, it has a function of turning off when the potential of the node N1 becomes Vn11 or higher.

The transistor 12 functions as a switch that selects whether to connect the input terminal IN2 and the output terminal OUT in accordance with the potential of the node N1. In the period T1, the transistor 12 has a function of supplying VSS to the output terminal OUT. In the period T2, the transistor 12 has a function of supplying VDD to the output terminal OUT.

The transistor 13 functions as a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the node N3. In the period T3, the transistor 13 has a function of supplying the power supply potential VSS to the output terminal OUT.

The transistor 14 functions as a switch that selects whether or not to connect the second power supply and the node N1 in accordance with the potential of the node N3. In the period T3, the transistor 13 has a function of supplying the power supply potential VSS to the node N1.

The transistor 15 has a function as a switch for selecting whether or not to connect the second power supply and the node N2 in accordance with the potential of the node N1. In the periods T1 and T2, the transistor 15 has a function of supplying the power supply potential VSS to the node N2.

The transistor 16 functions as a diode whose input terminal is a first power supply and whose output terminal is a node N2.

The transistor 17 has a function as a switch for selecting whether or not to connect the second power supply and the node N1 in accordance with a control signal supplied to the input terminal IN4. In the period T3 after the period T2, the transistor 17 has a function of supplying the power supply potential VSS to the node N1.

The transistor 18 functions as a switch that selects whether to connect the input terminal IN3 and the node N3 in accordance with the potential of the node N2. In the period T3, the transistor 18 has a function of supplying VDD to the node N3. In the period T4, the transistor 18 has a function of supplying VSS to the node N3.

The capacitive element 19 has a function for changing the potential of the node N1 in accordance with the potential of the output terminal OUT. In the period T2, the capacitor 19 has a function of increasing the potential of the node N1 by increasing the potential of the output terminal OUT.

As described above, in the flip-flop circuit 10 illustrated in FIG. 1, the transistors 13 and 14 are turned on in the period T3 and turned off in the period T4, so that the transistors 13 and 14 can be prevented from being constantly turned on. Accordingly, deterioration of the characteristics of the transistor 13 and the transistor 14 is suppressed. Therefore, the flip-flop circuit 10 illustrated in FIG. 1 can also suppress malfunction due to characteristic deterioration of the transistors 13 and 14.

When the transistors 13 and 14 are turned on, the power supply potential VSS is supplied to the output terminal OUT and the node N1. Therefore, the flip-flop circuit 10 illustrated in FIG. 1 can supply the power supply potential VSS to the output terminal OUT and the node N1 at regular intervals, and can reduce fluctuations in the potential of the output terminal OUT and the node N1.

In addition, since the flip-flop circuit 10 shown in FIG. 1 is entirely composed of N-channel transistors, amorphous silicon can be used for the semiconductor layer, and the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved. Furthermore, a large display panel can be created. Further, by using the flip-flop circuit of the present invention, the life of the semiconductor device can be extended even when an amorphous silicon transistor whose characteristics are easily deteriorated is used.

Note that in the period T1 to the period T4, an element such as a transistor or a switch may be inserted so that the flip-flop circuit 10 satisfies the states of FIGS.

Note that the capacitive element 19 is preferably formed of a gate wiring layer and a semiconductor layer. The gate wiring layer and the semiconductor layer are deposited via a gate insulating film. Since the film pressure of the gate insulating film is much thinner than that of other insulating layers such as an interlayer film, the capacitor has a small area and a large capacity when the gate insulating film is used as an insulator.

Note that the size (W / L) of the transistor 15 is preferably larger than the size of the transistor 16. Here, “W” indicates the channel width of the transistor, and “L” indicates the channel length of the transistor. When the transistor 15 is turned on, the potential of the node N2 is determined by the operating point between the transistor 15 and the transistor 16. That is, if the size of the transistor 15 is not sufficiently larger than the size of the transistor 16, the potential of the node N2 becomes high and the transistor 18 cannot be turned off. Therefore, the size of the transistor 15 needs to be sufficiently larger than the size of the transistor 16 so that the transistor 18 is turned off.

Further, the size of the transistor 15 is desirably four times or more the size of the transistor 16. More desirably, it is 10 times or more. When the power supply voltage is small, the transistor size ratio may be about four times. However, when the power supply voltage increases, the transistor size ratio needs to be about ten times.

Here, when a level shift circuit or the like is connected to the output terminal OUT of the flip-flop circuit 10, the transistor size ratio is desirably four times or more. This is because the amplitude voltage of the output signal of the flip-flop circuit 10 is increased by a level shift circuit or the like, so that the flip-flop circuit 10 often operates with a small power supply voltage.

When a level shift circuit or the like is not connected to the output terminal OUT of the flip-flop circuit 10, the transistor size ratio is desirably 10 times or more. This is because the output signal of the flip-flop circuit 10 is applied to some operation without level shift, and thus the flip-flop circuit 10 often operates with a large power supply voltage.

Note that the power supply potential and the potential of the control signal may be any potential as long as on / off of a target transistor can be controlled.

For example, the power supply potential VDD may be higher than the H level potential of the control signal. This is because the potential of the node N3 is Vn31 (VDD−Vth16−Vth18), and therefore the potential Vn31 of the node N3 increases as the power supply potential VDD increases. Therefore, the potential Vn31 of the node N3 is increased, so that the transistor 13 and the transistor 14 can be reliably turned on even when the threshold potential of the transistor 13 and the transistor 14 is increased due to deterioration of characteristics.

Further, the power supply potential VDD may be lower than the H level potential of the control signal as long as on / off of each transistor can be controlled.

Note that the capacitor 19 is not necessarily required if the gate capacitance (parasitic capacitance) between the gate terminal and the second terminal of the transistor 12 is sufficiently large.

For example, as in the flip-flop circuit 70 in FIG. Therefore, since the number of elements of the flip-flop circuit 70 is one less than the number of elements of the flip-flop circuit 10, the flip-flop circuit 70 can arrange each element with high density.

As another example, a capacitor 101 may be formed using the transistor 101 as in the flip-flop circuit 100 in FIG. This is because when the transistor 101 is on, the gate capacitance of the transistor 101 functions sufficiently as a capacitor.

Note that in the period T1 and the period T2 (during bootstrap operation), since the transistor 101 is on, a channel region is formed in the transistor 101, and the transistor 101 functions as a capacitor. On the other hand, in the period T3 and the period T4 (when the bootstrap operation is not performed), since the transistor 101 is off, a channel region is not formed in the transistor 101, and the transistor 101 does not function as a capacitor or has a small capacitance Functions as an element.

Here, as in the flip-flop circuit 70 in FIG. 7 described above, the capacitor 101 is formed using the transistor 101, so that the transistor 101 functions as a capacitor only when necessary (period T1 and period T2). When it is unnecessary (period T3 and period T4), it does not function as a capacitor, so that the flip-flop circuit 100 is less likely to malfunction due to a change in the potential of the node N1 or the output terminal OUT.

Note that the transistor 101 has the same polarity as the transistor 12.

Note that the first terminal of the transistor 11 may be connected anywhere as long as the node N1 can be in a floating state in the period T1 and the period T2.

For example, like the flip-flop circuit 80 in FIG. 8, the first terminal of the transistor 11 may be connected to the input terminal IN1. This is because even if the first terminal of the transistor 11 is connected to the input terminal IN1, the node N1 can be in a floating state in the period T1 and the period T2.

In the flip-flop circuit 10 in FIG. 1, when the potential of the input terminal IN1 changes, noise is generated in the first power supply due to the parasitic capacitance between the first terminal and the gate terminal of the transistor 11. Further, when a current flows from the first power supply to the node N1 by turning on / off the transistor 11, noise is generated in the first power supply due to a voltage drop of the current. These noises are generated by changes in the potential of the input terminal IN1.

Here, by connecting as in the flip-flop circuit 80 of FIG. 8 described above, the noise described above can be suppressed. Further, by suppressing the noise of the first power supply, other circuits using the first power supply can operate stably.

Note that the other circuit using the first power supply is an inverter circuit, a level shift circuit, a latch circuit, a PWC circuit, or the like connected to the output terminal OUT of the flip-flop circuit 80.

Note that various transistors can be used as the transistor 16 as long as an inverter circuit can be configured with the transistor 15. The transistor 16 does not necessarily have a rectifying property, and various elements can be used as long as the element generates voltage when a current flows.

For example, a resistive element 91 may be connected instead of the transistor 16 as in the flip-flop circuit 90 of FIG. This is because even if the resistor element 91 is connected instead of the transistor 16, the resistor element 91 and the transistor 15 can constitute an inverter circuit.

Note that when the transistor 15 is off, the potential of the node N2 becomes the same VDD as the potential of the first power supply. Further, the potential of the node N3 at this time is a value obtained by subtracting the threshold potential Vth18 of the transistor 18 from the power supply potential VDD (VDD−Vth18).

Here, as in the flip-flop circuit 90 of FIG. 9 described above, the resistance element 91 is used instead of the transistor 16, so that the potential of the node N2 can be increased even if the threshold potential of each transistor becomes high due to deterioration of characteristics. Becomes VDD, and the potential of the node N3 is only smaller than VDD by the threshold potential of the transistor 18, so that the transistors 13 and 14 can be easily turned on.

Note that although the input terminal IN1, the input terminal IN2, the input terminal IN3, and the input terminal IN4 are supplied with control signals, the present invention is not necessarily limited thereto.

For example, the input terminal IN1, the input terminal IN2, the input terminal IN3, and the input terminal IN4 may be supplied with the power supply potential VDD, may be supplied with the power supply potential VSS, or may be supplied with other potentials. It may be.

Note that although the first terminal of the transistor 11 and the first terminal of the transistor 16 are connected to the first power supply, the present invention is not necessarily limited thereto.

For example, the first terminal of the transistor 11 and the first terminal of the transistor 16 may be connected to different power sources. At this time, the potential of the power supply connected to the first terminal of the transistor 16 is preferably higher than the potential of the power supply connected to the first terminal of the transistor 11.

As another example, a control signal may be supplied to each of the first terminal of the transistor 11 and the first terminal of the transistor 16.

Note that although the first terminal of the transistor 13, the first terminal of the transistor 14, and the first terminal of the transistor 17 are connected to the second power supply, the present invention is not necessarily limited thereto.

For example, the first terminal of the transistor 13, the first terminal of the transistor 14, and the first terminal of the transistor 17 may be connected to different power sources.

As another example, control signals may be supplied to the first terminal of the transistor 13, the first terminal of the transistor 14, and the first terminal of the transistor 17, respectively.

In the flip-flop circuit 10 shown in FIG. 1, all N-channel transistors are used, but all may be P-channel transistors. Here, FIG. 11 shows a flip-flop circuit in the case where all of the transistors are P-channel transistors.

FIG. 11 illustrates one mode of the flip-flop circuit 110 included in the shift register circuit of the present invention. The shift register circuit of the present invention has a plurality of flip-flop circuits 110. A flip-flop circuit 110 illustrated in FIG. 11 includes a transistor 111, a transistor 112, a transistor 113, a transistor 114, a transistor 115, a transistor 116, a transistor 117, a transistor 118, and a capacitor 119 having two electrodes. Note that the capacitor 119 is not necessarily required when the gate capacitance of the transistor 112 can be substituted.

As shown in the flip-flop circuit 110, the gate terminal of the transistor 111 is connected to the input terminal IN1, the first terminal is connected to the first power supply, the second terminal is the gate terminal of the transistor 112, and the second terminal of the transistor 114. To the gate terminal of the transistor 115, the second terminal of the transistor 117, and the second electrode of the capacitor 119. A first terminal of the transistor 115 is connected to the second power supply, and a second terminal is connected to the second terminal of the transistor 116 and the gate terminal of the transistor 118. A gate terminal and a first terminal of the transistor 116 are connected to a first power source. A first terminal of the transistor 118 is connected to the input terminal IN 3, and a second terminal is connected to the gate terminal of the transistor 113 and the gate terminal of the transistor 114. A first terminal of the transistor 113 is connected to the second power supply, and a second terminal is connected to the first electrode of the capacitor 119, the second terminal of the transistor 112, and the output terminal OUT. A first terminal of the transistor 112 is connected to the input terminal IN2. A first terminal of the transistor 114 is connected to the second power source. The gate terminal of the transistor 117 is connected to the input terminal IN4, and the first terminal is connected to the second power source.

Note that in the flip-flop circuit 110, the second terminal of the transistor 111, the gate terminal of the transistor 112, the second terminal of the transistor 114, the gate terminal of the transistor 115, the second terminal of the transistor 117, and the second electrode of the capacitor 119 Let the node be N1. A node of the second terminal of the transistor 115 and the second terminal of the transistor 116 is N2. A node of the gate terminal of the transistor 113, the gate terminal of the transistor 114, and the second terminal of the transistor 118 is N3.

In addition, the power supply potential VSS is supplied to the first power supply, and the power supply potential VDD is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VSS of the first power supply and the power supply potential VDD of the second power supply corresponds to the power supply voltage of the flip-flop circuit 110. The power supply potential VDD is higher than the power supply potential VSS.

Control signals are supplied to the input terminals IN1 to IN4, respectively. The output terminal OUT outputs an output signal. The output signal of the previous flip-flop circuit 110 is supplied to the input terminal IN1 as a control signal. The output signal of the flip-flop circuit 110 at the next stage is supplied as a control signal to the input terminal IN4.

In addition, the transistors 111 to 118 are each a P-channel type. Note that the transistors 111 to 118 may each be an N-channel type.

Next, operation of the flip-flop circuit 110 illustrated in FIG. 11 will be described with reference to a timing chart illustrated in FIG. FIG. 12 shows a timing chart of the control signal supplied to the input terminal IN1 to the input terminal IN4 shown in FIG. 11, the output signal output from the output terminal OUT, and the potentials of the nodes N1 to N3. . Note that the timings of the control signal and the output signal are inverted between the H level and the L level as compared with the case where all of them are composed of N channel transistors (FIG. 1). Further, the timing chart shown in FIG. 12 is divided into periods T1 to T4 for convenience.

Note that the period T3 and the period T4 are sequentially repeated in the period after the period T4. In FIG. 12, the period T1 is defined as a selection preparation period, the period T2 is defined as a selection period, and the periods T3 and T4 are defined as non-selection periods. That is, one selection preparation period, one selection period, and a plurality of non-selection periods are repeated in order.

In the timing chart shown in FIG. 12, the control signal and the output signal are digital signals having binary values. The binary potential of the digital signal is VDD (hereinafter also referred to as potential VDD or H level) that is the same as the power supply potential of the second power supply when the signal is an H signal, and the first potential when the signal is an L signal. VSS which is the same potential as the power source potential of the first power source (hereinafter also referred to as potential VSS or L level).

Next, the operation of each period of the flip-flop circuit 110 will be described.

First, operation of the flip-flop circuit 110 in the period T1 is described.

In the period T1, the input terminal IN1 is at an L level and the transistor 111 is turned on. The input terminal IN4 becomes H level and the transistor 117 is turned off. Since the node N3 maintains VDD obtained in a period T3 described later, the transistor 114 is turned off. The node N1 is electrically connected to the first power supply through the transistor 111, and the potential of the node N1 is decreased to Vn11. When the node N1 becomes Vn11, the transistor 111 is turned off. Here, Vn11 is a value (VSS + | Vth111 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth111 of the transistor 111. Note that Vn11 is a potential at which the transistor 112 and the transistor 115 can be turned on.

The potential of the node N1 becomes Vn11, the transistor 111 is turned off, and the transistor 112 and the transistor 115 are turned on. The node N2 is electrically connected to the second power supply via the transistor 115, and is electrically connected to the first power supply via the transistor 116, and the potential of the node N2 becomes Vn21. Here, Vn21 is determined by the operating point of the transistor 116 and the transistor 115. Note that the transistor 115 and the transistor 116 form an inverter using the two transistors. Therefore, when an L level signal is input to the gate terminal (node N1) of the transistor 115, an H level signal is input to the node N2. Here, Vn21 is a potential at which the transistor 118 can be turned off. Therefore, even when the input terminal IN3 is at the L level, the transistor 118 is off, so that the node N3 can maintain VDD. Since the input terminal IN2 becomes H level and the output terminal OUT is electrically connected to the input terminal IN2 through the transistor 112, the potential of the output terminal OUT becomes VDD.

Since the potential of the node N2 is Vn21 and the transistor 118 is turned off, the node N3 maintains VDD, and the transistor 113 and the transistor 114 are turned off.

Through the above operation, in the period T1, the transistor 112 is turned on and the output terminal OUT is set to the H level. Further, since the transistor 111 is off, the node N1 is in a floating state.

Next, an operation of the flip-flop circuit 110 in the period T2 is described.

In the period T2, the input terminal IN1 is at an H level and the transistor 111 is off. The input terminal IN4 remains at the H level, and the transistor 117 is off. Therefore, the node N1 is in a floating state following the period T1, and maintains the potential Vn11 of the period T1.

Since the potential of the node N1 is maintained at Vn11, the transistor 112 is turned on. Then, the input terminal IN2 becomes H level. Then, the output terminal OUT becomes conductive with the input terminal IN2 through the transistor 112, and the potential of the output terminal OUT decreases from VDD. The potential of the node N1 changes to Vn12 due to capacitive coupling of the capacitor 119, and the transistor 112 is kept on. A so-called bootstrap operation is performed. As a result, the output terminal OUT decreases to a potential equal to VSS which is the potential of the input terminal IN2. Note that Vn12 is equal to or lower than a value (VSS− | Vth112 |) obtained by subtracting the absolute value of the threshold potential Vth112 of the transistor 112 from the potential VSS. Since the input terminal IN2 is at L level and the output terminal OUT is electrically connected to the input terminal IN2 through the transistor 112, the potential of the output terminal OUT becomes VSS.

Even when the potential of the node N1 becomes Vn12, the transistor 115 remains off. Therefore, the potential of the node N2 and the potential of the node N3 are the same as those in the period T1.

Through the above operation, in the period T2, the output terminal OUT is set to VSS by lowering the potential of the node N1 in the floating state by the bootstrap operation.

Next, an operation of the flip-flop circuit 110 in the period T3 is described.

In the period T3, the input terminal IN1 remains at the H level, and the transistor 111 is off. The input terminal IN4 becomes L level and the transistor 117 is turned on. Then, the node N1 becomes conductive with the second power supply through the transistor 117, and the potential of the node N1 becomes VDD.

The potential of the node N1 becomes VDD, and the transistor 112 and the transistor 115 are turned off. Since the node N2 is electrically connected to the first power supply through the transistor 116, the potential of the node N2 is decreased to Vn22. Here, Vn22 is a value (VSS + | Vth116 |) that is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth116 of the transistor 116. Note that Vn22 is a potential at which the transistor 118 can be turned on.

The potential of the node N2 becomes Vn22, and the transistor 118 is turned on. Since the input terminal IN3 is at the L level, the node N3 is electrically connected to the input terminal IN3 through the transistor 118, and the potential of the node N3 becomes Vn31. Here, Vn31 is a value (Vn22 + | Vth118 |) which is the sum of the potential Vn22 of the node N2 and the absolute value of the threshold potential Vth118 of the transistor 118. Note that Vn31 is a value (VSS + | Vth116 | + | Vth118 |) that is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth116 of the transistor 116 and the absolute value of the threshold potential Vth118 of the transistor 118. Equivalent to. Vn31 is a voltage that can turn on the transistor 113 and the transistor 114.

The potential of the node N3 becomes Vn31, and the transistor 113 is turned on. Since the output terminal OUT is electrically connected to the second power supply through the transistor 113, the potential of the output terminal OUT becomes VDD.

Through the above operation, in the period T3, VDD is supplied to the node N1, and the transistor 112 and the transistor 115 are turned off. Further, the node N3 is set to the L level, and the transistor 113 and the transistor 114 are turned on. Therefore, the potential of the output terminal OUT is set to VDD, and the output terminal OUT is set to H level.

Next, operation of the flip-flop circuit 110 in the period T4 is described.

In the period T4, the input terminal IN3 is at an H level, and the potential of the node N3 is VDD. Accordingly, the transistor 113 is turned off. The transistor 114 is also turned off. The input terminal IN4 becomes H level and the transistor 117 is turned off. Then, the node N1 enters a floating state, and the potential of the node N1 maintains VDD.

Since the potential of the node N1 remains at VDD, the transistor 112 remains off and the transistor 115 also remains off. Therefore, the node N2 remains Vn22 and the transistor 118 remains off.

Since the transistor 112 and the transistor 113 are turned off, the output terminal OUT is in a floating state. Therefore, the potential of the output terminal OUT is maintained at VDD.

Through the above operation, in the period T4, the potential of the output terminal OUT is maintained at VDD, so that the transistor 113 and the transistor 114 can be turned off. As described above, since the transistor 113 and the transistor 114 are not always turned on, deterioration in characteristics of the transistor 113 and the transistor 114 can be suppressed.

A relationship between the periods T1 to T4 will be described. The next period after the period T1 is the period T2, the next period after the period T2 is the period T3, and the next period after the period T3 is the period T4. Here, the period subsequent to the period T4 is the period T1 or the period T3. That is, the period following the period T4 is the period T1 if the input terminal IN1 is at the L level, and is the period T3 if the input terminal IN1 remains at the H level. In the case where the period T3 is a period subsequent to the period T4, the input terminal IN4 remains at the H level and the transistor 117 remains off.

Here, the functions of the transistors 111 to 118 and the capacitor 119 are the same as those of the transistors 11 to 18 and the capacitor 19 illustrated in FIG. 1, respectively.

In this manner, in the flip-flop circuit 110 illustrated in FIG. 11, the transistor 113 and the transistor 114 are turned on in the period T3 and turned off in the period T4, so that the transistor 113 and the transistor 114 are always on. It is done. Accordingly, deterioration in characteristics of the transistor 113 and the transistor 114 is suppressed. Therefore, the flip-flop circuit 110 illustrated in FIG. 11 can also suppress malfunction due to deterioration in characteristics of the transistor 113 and the transistor 114.

Further, when the transistors 113 and 114 are turned on, the power supply potential VDD is supplied to the output terminal OUT and the node N1. Therefore, the flip-flop circuit 110 illustrated in FIG. 11 can supply the power supply potential VDD to the output terminal OUT and the node N1 at regular intervals, and can reduce fluctuations in the potential of the output terminal OUT and the node N1.

In addition, the flip-flop circuit 110 illustrated in FIG. 11 can use polysilicon for the semiconductor layer, so that the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved. Furthermore, since the characteristics of polysilicon are not easily deteriorated, the long life of the semiconductor device can be extended as compared with the case where amorphous silicon is used for the semiconductor layer. Further, by using the flip-flop circuit of the present invention, the lifetime of the semiconductor device can be further extended. Further, since the mobility of the transistor using polysilicon is large, the flip-flop circuit 110 can operate at high speed.

Note that the capacitor 119 is preferably formed using a gate wiring layer and a semiconductor layer. The gate wiring layer and the semiconductor layer are deposited via a gate insulating film. Since the film pressure of the gate insulating film is much thinner than that of other insulating layers such as an interlayer film, the capacitor has a small area and a large capacity when the gate insulating film is used as an insulator.

Note that the size (W / L) of the transistor 115 is preferably larger than the size of the transistor 116. Here, “W” indicates the channel width of the transistor, and “L” indicates the channel length of the transistor. When the transistor 115 is turned on, the potential of the node N2 is determined by the operating point of the transistor 115 and the transistor 116. That is, if the size of the transistor 115 is not sufficiently larger than the size of the transistor 116, the potential of the node N2 becomes high and the transistor 118 cannot be turned off. Therefore, the size of the transistor 115 needs to be sufficiently larger than the size of the transistor 116 so that the transistor 118 is turned off.

In addition, the size of the transistor 115 is preferably four times or more the size of the transistor 116. More desirably, it is 10 times or more. When the power supply voltage is small, the transistor size ratio may be about four times. However, when the power supply voltage increases, the transistor size ratio needs to be about ten times.

Here, when a level shift circuit or the like is connected to the output terminal OUT of the flip-flop circuit 110, the transistor size ratio is desirably four times or more. This is because the amplitude voltage of the output signal of the flip-flop circuit 110 is increased by a level shift circuit or the like, so that the flip-flop circuit 110 often operates with a small power supply voltage.

In the case where a level shift circuit or the like is not connected to the output terminal OUT of the flip-flop circuit 110, the transistor size ratio is desirably 10 times or more. This is because the output signal of the flip-flop circuit 110 is applied to some operation without level shift, and thus the flip-flop circuit 110 often operates with a large power supply voltage.

Note that the power supply potential and the potential of the control signal may be any potential as long as on / off of a target transistor can be controlled.

For example, the power supply potential VSS may be lower than the L level potential of the control signal. This is because the potential of the node N3 is Vn31 (VSS + | Vth16 | + | Vth18 |), and therefore, the potential Vn31 of the node N3 decreases as the power supply potential VSS decreases. Therefore, the potential Vn31 at the node N3 is lowered, so that the transistor 113 and the transistor 114 can be reliably turned on even when the threshold potential of the transistor 113 and the transistor 114 is lowered due to characteristic deterioration.

Further, the power supply potential VSS may be higher than the L-level potential of the control signal as long as on / off of each transistor can be controlled.

Note that the capacitor 119 is not necessarily required if the gate capacitance (parasitic capacitance) between the gate terminal and the second terminal of the transistor 112 is sufficiently large.

For example, the capacitor 119 does not have to be connected as in the flip-flop circuit 130 in FIG. Therefore, since the number of elements of the flip-flop circuit 130 is one less than the number of elements of the flip-flop circuit 110, the flip-flop circuit 130 can arrange each element with high density.

As another example, a capacitor 161 may be formed using a transistor 161 as in the flip-flop circuit 160 in FIG. This is because if the transistor 161 is on, the gate capacitance of the transistor 161 functions sufficiently as a capacitor.

Note that in the period T1 and the period T2 (during bootstrap operation), since the transistor 161 is on, a channel region is formed in the transistor 161, and the transistor 161 functions as a capacitor. On the other hand, in the period T3 and the period T4 (when the bootstrap operation is not performed), the transistor 161 is off, so that the channel region is not formed in the transistor 101 and the transistor 161 does not function as a capacitor or has a small capacitance. Functions as an element.

Here, as in the flip-flop circuit 160 in FIG. 16 described above, the capacitor 161 is formed using the transistor 161, so that the transistor 161 functions as a capacitor only when necessary (period T1 and period T2). When not necessary (period T3 and period T4), the flip-flop circuit 160 is less likely to malfunction due to a change in the potential of the node N1 or the output terminal OUT.

Note that the transistor 161 has the same polarity as the transistor 112.

Note that the first terminal of the transistor 111 may be connected anywhere as long as the node N1 can be in a floating state in the period T1 and the period T2.

For example, as in the flip-flop circuit 140 in FIG. 14, the first terminal of the transistor 111 may be connected to the input terminal IN1. This is because even when the first terminal of the transistor 111 is connected to the input terminal IN1, the node N1 can be in a floating state in the period T1 and the period T2.

Note that in the flip-flop circuit 110 in FIG. 11, when the potential of the input terminal IN <b> 1 changes, noise is generated in the first power supply due to the parasitic capacitance between the first terminal and the gate terminal of the transistor 111. Further, when a current flows from the first power supply to the node N1 by turning on / off the transistor 111, noise is generated in the first power supply due to a voltage drop of the current. These noises are generated by changes in the potential of the input terminal IN1.

Here, by connecting as in the flip-flop circuit 140 in FIG. 14 described above, the noise described above can be suppressed. Further, by suppressing the noise of the first power supply, other circuits using the first power supply can operate stably.

Note that the other circuit using the first power supply is an inverter circuit, a level shift circuit, a latch circuit, a PWC circuit, or the like connected to the output terminal OUT of the flip-flop circuit 140.

Note that various transistors can be used as the transistor 116 as long as an inverter circuit can be formed with the transistor 115. The transistor 116 is not necessarily rectifying, and various elements can be used as long as they generate voltage when a current flows.

For example, a resistance element 151 may be connected instead of the transistor 116 as in the flip-flop circuit 150 in FIG. This is because even if the resistor element 151 is connected instead of the transistor 116, the resistor element 151 and the transistor 115 can constitute an inverter circuit.

Note that when the transistor 115 is off, the potential of the node N2 becomes VSS which is the same as the potential of the first power supply. Further, the potential of the node N3 at this time is a value (VSS + | Vth118 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth118 of the transistor 118.

Here, as in the flip-flop circuit 150 in FIG. 15 described above, the resistance element 151 is used instead of the transistor 116, so that the potential of the node N2 can be increased even if the threshold potential of each transistor becomes high due to deterioration of characteristics. Becomes VSS, and the potential of the node N3 is only higher than VSS by the threshold potential of the transistor 118, so that the transistor 113 and the transistor 114 can be easily turned on.

Note that although the input terminal IN1, the input terminal IN2, the input terminal IN3, and the input terminal IN4 are supplied with control signals, the present invention is not necessarily limited thereto.

For example, the input terminal IN1, the input terminal IN2, the input terminal IN3, and the input terminal IN4 may be supplied with the power supply potential VDD, may be supplied with the power supply potential VSS, or may be supplied with other potentials. It may be.

Note that although the first terminal of the transistor 111 and the first terminal of the transistor 116 are connected to the first power supply, the present invention is not necessarily limited thereto.

For example, the first terminal of the transistor 111 and the first terminal of the transistor 116 may be connected to different power sources. At this time, the potential of the power supply connected to the first terminal of the transistor 116 is preferably higher than the potential of the power supply connected to the first terminal of the transistor 111.

As another example, a control signal may be supplied to each of the first terminal of the transistor 111 and the first terminal of the transistor 116.

Note that although the first terminal of the transistor 113, the first terminal of the transistor 114, and the first terminal of the transistor 117 are connected to the second power supply, the present invention is not necessarily limited thereto.

For example, the first terminal of the transistor 113, the first terminal of the transistor 114, and the first terminal of the transistor 117 may be connected to different power sources.

Note that this embodiment mode can be freely combined with any description in other embodiment modes and embodiments in this specification. That is, the shift register circuit of the present invention supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

(Embodiment 2)
In this embodiment, a structure of a shift register circuit of the present invention will be described.

FIG. 17 shows one mode of a shift register circuit of the present invention. The shift register circuit illustrated in FIG. 17 includes a plurality of flip-flop circuits 171, a control signal line 172, a control signal line 173, and a control signal line 174.

As shown in the shift register circuit of FIG. 17, each flip-flop circuit 171 has an input terminal IN1 connected to an output terminal OUT of the preceding flip-flop circuit 171. The output terminal OUT is connected to the input terminal IN1 of the next-stage flip-flop circuit 171, the input terminal IN4 of the previous-stage flip-flop circuit 171, and the output terminal SRout of the shift register circuit. However, the input terminal IN 1 of the first-stage flip-flop circuit 171 is connected to the control signal line 172. The input terminal IN4 of the flip-flop circuit 171 at the final stage is connected to a power source. In the odd-numbered flip-flop circuit 171, the input terminal IN2 is connected to the control signal line 173, and the input terminal IN3 is connected to the control signal line 174. On the other hand, in the even-numbered flip-flop circuit 171, the input terminal IN2 is connected to the control signal line 174, and the input terminal IN3 is connected to the control signal line 173.

Note that the flip-flop circuit 171 can be similar to the flip-flop circuit described in Embodiment 1.

Further, the input terminal IN1 to the input terminal IN4 and the output terminal OUT of the flip-flop circuit 171 can be similar to those described in Embodiment 1.

Further, in the shift register circuit of the present invention, the first stage output terminal SRout is the output terminal SRout1, the second stage output terminal SRout is the output terminal SRout2, the third stage output terminal SRout is the output terminal SRout3, and the fourth stage. The output terminal SRout of the eye is the output terminal SRout4, and the output terminal SRout of the nth stage is the output terminal SRoutn.

Further, the flip-flop circuit 171 does not show a power supply and a power supply line for convenience. As the power source and the power source line, the first power source and the second power source described in Embodiment 1 can be used. Therefore, the potential difference (VDD−VSS) between the power supply potential VDD of the first power supply and the power supply potential VSS of the second power supply corresponds to the power supply voltage of the flip-flop circuit 171.

Control signals SSP, CK, and CKB are supplied to the control signal line 172 to the control signal line 174, respectively. The output signals of the first to fourth and n-th flip-flop circuits 171 are supplied to the output terminals SRout1 to SRout4 and the output terminal SRoutn of the shift register circuit, respectively.

Next, operation of the shift register circuit illustrated in FIG. 17 will be described with reference to a timing chart illustrated in FIG. 18 shows the control signal SSP, the control signal CK and the control signal CKB supplied to the control signal line 172 to the control signal line 174 shown in FIG. 17, and the outputs of the output terminal SRout1 to the output terminal SRout4 and the output terminal SRoutn, respectively. The timing chart of a signal is shown. Further, the timing chart shown in FIG. 18 is divided into a period T0 to a period T5, a period Tn, and a period Tn + 1 for convenience.

FIG. 18 is a timing chart in the case where the transistors of the flip-flop circuit 171 are each N-channel type. That is, FIG. 18 is a timing chart in the case where the flip-flop circuit shown in FIGS. 1, 7, 8, 9, and 10 is used as the flip-flop circuit 171.

In the timing chart shown in FIG. 18, the control signal and the output signal are digital signals having the same binary values as in the first embodiment.

The operation of the shift register circuit illustrated in FIG. 17 is described with reference to FIG.

First, operation of the shift register circuit in the period T0 is described. In the period T0, the control signal SSP becomes H level, the control signal CK becomes L level, and the control signal CKB becomes H level.

In the first-stage flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 becomes L level. Therefore, the output terminal OUT becomes L level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-numbered flip-flop circuit 171 except the first stage, the input terminal IN1 becomes L level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 becomes L level. Therefore, the output terminal OUT becomes L level. This state is the same as the period T3 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171, the input terminal IN1 becomes L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 becomes L level. Therefore, the output terminal OUT becomes L level. This state is similar to the period T4 in the timing chart shown in FIG.

Thus, the output terminals SRout of all shift register circuits are at the L level.

Next, operation of the shift register circuit in the period T1 is described. In the period T1, the control signal SSP becomes L level, the control signal CK becomes H level, and the control signal CKB becomes L level.

In the first-stage flip-flop circuit 171, the input terminal IN1 becomes L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 remains L level. Therefore, the output terminal OUT becomes H level. This state is similar to the period T2 in the timing chart shown in FIG.

In the second-stage flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 remains L level. Therefore, the output terminal OUT remains at the L level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-stage flip-flop circuit 171 except the first stage, the input terminal IN1 remains at L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 is at L level. It remains. Therefore, the output terminal OUT remains at the L level. This state is similar to the period T4 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171 except the second stage, the input terminal IN1 remains at L level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 is at L level. It remains. Therefore, the output terminal OUT remains at the L level. This state is the same as the period T3 in the timing chart shown in FIG.

Thus, the output terminal SRout1 of the shift register circuit becomes H level, and the other output terminals SRout remain at L level.

Next, operation of the shift register circuit in the period T2 is described. In the period T2, the control signal SSP becomes L level, the control signal CK becomes L level, and the control signal CKB becomes H level.

In the first-stage flip-flop circuit 171, the input terminal IN1 remains at L level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 becomes H level. Therefore, the output terminal OUT becomes L level. This state is the same as the period T3 in the timing chart shown in FIG.

In the second-stage flip-flop circuit 171, the input terminal IN1 becomes L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 remains L level. Therefore, the output terminal OUT becomes H level. This state is similar to the period T2 in the timing chart shown in FIG.

In the third-stage flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 remains L level. Therefore, the output terminal OUT remains at the L level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-numbered flip-flop circuit 171 except the first and third stages, the input terminal IN1 remains at L level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 remains at the L level. Therefore, the output terminal OUT remains at the L level. This state is the same as the period T3 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171 except the second stage, the input terminal IN1 remains at L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 is at L level. It remains. Therefore, the output terminal OUT remains at the L level. This state is similar to the period T4 in the timing chart shown in FIG.

Thus, the output terminal SRout1 of the shift register circuit becomes L level, the output terminal SRout2 becomes H level, and the other output terminals SRout remain at L level.

Similarly, in the subsequent period, the output terminal SRout3 of the shift register circuit becomes H level in the period T3, the output terminal SRout4 of the shift register circuit becomes H level in the period T4, and the fifth stage of the shift register circuit in period T5. The output terminal SRout5 is at the H level, and the n-th output terminal SRoutn of the shift register circuit is at the H level in the period Tn. As described above, the output terminal of the shift register circuit becomes H level in order for only one period. One period is a half cycle of the control signal CK or the control signal CKB.

Through the above operation, the output terminal SRout of the shift register circuit illustrated in FIG. 17 can be set to the H level step by step. In addition, when the flip-flop circuit described in Embodiment 1 is used as the flip-flop circuit 171, the flip-flop circuit illustrated in FIG. 17 is unlikely to malfunction due to deterioration of transistor characteristics and output signal noise is reduced.

FIG. 18 shows a timing chart when the transistor of the flip-flop circuit 171 is an N-channel type. FIG. 19 shows a timing chart when the transistor of the flip-flop circuit 171 is a P-channel type. That is, FIG. 19 is a timing chart when the flip-flop circuit shown in FIGS. 11, 13, 14, 15, and 16 is used as the flip-flop circuit 171.

Next, operation of the shift register circuit illustrated in FIG. 17 is described with reference to a timing chart illustrated in FIG. 19 shows the control signal SSP, the control signal CK, and the control signal CKB supplied to the control signal line 172 to the control signal line 174 shown in FIG. 17, and the outputs of the output terminal SRout1 to the output terminal SRout4 and the output terminal SRoutn, respectively. The timing chart of a signal is shown. In addition, the timing chart illustrated in FIG. 19 is divided into a period T0 to a period T5, a period Tn, and a period Tn + 1 for convenience. Note that the timings of the control signal and the output signal are inverted between the H level and the L level as compared to the case where the flip-flop circuits 171 are all formed of N-channel transistors (FIG. 18).

In the timing chart shown in FIG. 19, the control signal and the output signal are digital signals having the same binary values as in the first embodiment.

The operation of the shift register circuit illustrated in FIG. 17 is described with reference to FIG.

First, operation of the shift register circuit in the period T0 is described. In the period T0, the control signal SSP becomes L level, the control signal CK becomes H level, and the control signal CKB becomes L level.

In the flip-flop circuit 171 at the first stage, the input terminal IN1 is at L level, the input terminal IN2 is at H level, the input terminal IN3 is at L level, and the input terminal IN4 is at H level. Therefore, the output terminal OUT becomes H level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-numbered flip-flop circuit 171 except the first stage, the input terminal IN1 becomes H level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 becomes H level. Therefore, the output terminal OUT becomes H level. This state is the same as the period T3 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 becomes H level. Therefore, the output terminal OUT becomes H level. This state is similar to the period T4 in the timing chart shown in FIG.

Thus, the output terminals SRout of all shift register circuits are at the H level.

Next, operation of the shift register circuit in the period T1 is described. In the period T1, the control signal SSP becomes H level, the control signal CK becomes L level, and the control signal CKB becomes H level.

In the first-stage flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 remains H level. Therefore, the output terminal OUT becomes L level. This state is similar to the period T2 in the timing chart shown in FIG.

In the second-stage flip-flop circuit 171, the input terminal IN1 becomes L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 remains at H level. Therefore, the output terminal OUT remains at the H level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-numbered flip-flop circuit 171 except the first stage, the input terminal IN1 remains at H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 is at H level. It remains. Therefore, the output terminal OUT remains at the H level. This state is similar to the period T4 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171 except the second stage, the input terminal IN1 remains at the H level, the input terminal IN2 is at the H level, the input terminal IN3 is at the L level, and the input terminal IN4 is at the H level. It remains. Therefore, the output terminal OUT remains at the H level. This state is the same as the period T3 in the timing chart shown in FIG.

Thus, the output terminal SRout1 of the shift register circuit becomes L level, and the other output terminals SRout remain at H level.

Next, operation of the shift register circuit in the period T2 is described. In the period T2, the control signal SSP becomes H level, the control signal CK becomes H level, and the control signal CKB becomes L level.

In the first-stage flip-flop circuit 171, the input terminal IN1 remains at H level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 becomes L level. Therefore, the output terminal OUT becomes H level. This state is the same as the period T3 in the timing chart shown in FIG.

In the second-stage flip-flop circuit 171, the input terminal IN1 becomes H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 remains at H level. Therefore, the output terminal OUT becomes L level. This state is similar to the period T2 in the timing chart shown in FIG.

In the third-stage flip-flop circuit 171, the input terminal IN1 becomes L level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 remains H level. Therefore, the output terminal OUT remains at the H level. This state is the same as the period T1 in the timing chart shown in FIG.

In the odd-stage flip-flop circuit 171 except the first stage and the third stage, the input terminal IN1 remains at H level, the input terminal IN2 becomes H level, the input terminal IN3 becomes L level, and the input terminal IN4 remains at the H level. Therefore, the output terminal OUT remains at the H level. This state is the same as the period T3 in the timing chart shown in FIG.

In the even-numbered flip-flop circuit 171 except the second stage, the input terminal IN1 remains at H level, the input terminal IN2 becomes L level, the input terminal IN3 becomes H level, and the input terminal IN4 is at H level. It remains. Therefore, the output terminal OUT remains at the H level. This state is similar to the period T4 in the timing chart shown in FIG.

Thus, the output terminal SRout1 of the shift register circuit becomes H level, the output terminal SRout2 becomes L level, and the other output terminals SRout remain at H level.

Similarly, in the subsequent period, the output terminal SRout3 of the shift register circuit becomes L level in the period T3, the output terminal SRout4 of the shift register circuit becomes L level in the period T4, and the fifth stage of the shift register circuit in period T5. The output terminal SRout5 is at the L level, and the n-th output terminal SRoutn of the shift register circuit is at the L level in the period Tn. As described above, the output terminal of the shift register circuit sequentially becomes L level for only one period. One period is a half cycle of the control signal CK or the control signal CKB.

Through the above operation, the output terminal SRout of the shift register circuit illustrated in FIG. 17 can be set to the L level step by step. In addition, when the flip-flop circuit described in Embodiment 1 is used as the flip-flop circuit 171, the flip-flop circuit illustrated in FIG. 17 is unlikely to malfunction due to deterioration of transistor characteristics and output signal noise is reduced.

Note that the flip-flop circuit 171 may be any flip-flop circuit as long as it can supply a selection signal to the output terminal SRout of the shift register circuit in order from the first stage.

Note that the output terminal OUT of the flip-flop circuit 171 may be connected to the output terminal SRout of the shift register circuit through any element and circuit. Any elements and circuits include logic circuits such as inverter circuits, buffer circuits, NAND circuits, NOR circuits, tristate buffer circuits, and PWC circuits, switches, resistor elements, capacitor elements, and other elements. Various circuits can be formed by combining these elements and circuits.

Although the control signal is supplied to each of the control signal lines 172 to 174, the present invention is not necessarily limited to this.

For example, the control signal line 172 to the control signal line 174 may be supplied with the power supply potential VDD, may be supplied with the power supply potential VSS, or may be supplied with another potential.

Note that although the control signal CK is supplied to the control signal line 173 and the control signal CKB is supplied to the control signal line 174, the present invention is not necessarily limited thereto.

For example, the control signal line 173 may be supplied with the control signal CK, and the control signal line 174 may be supplied with an inverted signal of the control signal CK through an inverter circuit. Further, an inverted signal of the control signal CKB may be supplied to the control signal line 173 through an inverter circuit, and the control signal CKB may be supplied to the control signal line 174. Note that this inverter circuit is preferably formed over the same substrate as the shift register circuit.

Note that the input terminal IN4 of the flip-flop circuit 171 in the final stage is connected to a power supply, but the present invention is not necessarily limited to this.

For example, the input terminal IN4 of the flip-flop circuit 171 at the final stage may be connected to any one of the control signal line 172 to the control signal line 174, may be connected to another control signal, It may be connected to the output terminal OUT of the flip-flop circuit 171 in the stage.

Note that this embodiment mode can be freely combined with any description in other embodiment modes and embodiments in this specification. That is, the shift register circuit of the present invention supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

(Embodiment 3)
In this embodiment, an example of a structure in which the flip-flop circuit described in Embodiment 1 and the shift register circuit described in Embodiment 2 are used as part of the driver circuit will be described.

A configuration example of a drive circuit that can be applied to a gate driver as the drive circuit will be described with reference to FIGS. However, the drive circuits of FIGS. 20 to 27 are not only applicable to gate drivers, but can be applied to any circuit configuration.

FIG. 20 shows one mode of the gate driver of the present invention. The gate driver of the present invention includes a shift register circuit 200 and a buffer circuit 201.

As shown in the gate driver of FIG. 20, the output terminal SRout of the shift register circuit 200 is connected to the output terminal GDout of the gate driver via the buffer circuit 201.

Note that the shift register circuit 200 is similar to that described in Embodiment 2.

Further, the output terminal SRout1 to the output terminal SRout4 and the output terminal SRoutn of the shift register circuit 200 are the same as those described in Embodiment 2.

In the gate driver of the present invention, the first stage output terminal GDout is the output terminal GDout1, the second stage output terminal GDout is the output terminal GDout2, the third stage output terminal GDout is the output terminal GDout, and the nth stage. The output terminal GDout is referred to as an output terminal GDoutn.

The buffer circuit 201 includes a logic circuit such as an inverter circuit, a buffer circuit, a NAND circuit, a NOR circuit, a tristate buffer circuit, and a PWC circuit, a switch, a resistance element, a capacitor element, or other elements. Various circuits can be configured by combining these elements and circuits.

In the gate driver of FIG. 20, the power supply line and the control signal line are not shown for convenience.

In the case where the shift register circuit 200 is formed using an N-channel transistor, the buffer circuit 201 is preferably formed using an N-channel transistor. In the case where the shift register circuit 200 is configured with a P-channel transistor, it is desirable that the buffer circuit 201 is also configured with a P-channel transistor.

In the case where the shift register circuit 200 includes N-channel transistors, the output signal of the shift register circuit 200 is the same as that in the timing chart of FIG. When the shift register circuit 200 includes a P-channel transistor, the output signal of the shift register circuit 200 is the same as that in the timing chart of FIG.

Here, a specific configuration example of the buffer circuit 201 will be described. FIG. 21 to FIG. 27 are configuration examples of gate drivers including buffer circuits. However, the buffer circuit 201 is not limited to the configuration shown in FIGS.

FIG. 21 specifically illustrates one mode of a gate driver including the buffer circuit of the present invention. The gate driver in FIG. 21 includes a shift register circuit 200 and a buffer circuit 210. The buffer circuit 210 includes a first-stage inverter circuit 211A and a second-stage inverter circuit 211B.

As shown in the gate driver in FIG. 21, the output terminal SRout of the shift register circuit 200 is connected to the output terminal GDout of the gate driver via the buffer circuit 210.

A connection relationship of the buffer circuit 210 will be described. The input terminal IN of the inverter circuit 211A is connected to the output terminal SRout of the shift register circuit 200, and the output terminal OUT is connected to the input terminal IN of the inverter circuit 211B. The output terminal OUT of the inverter circuit 211B is connected to the output terminal GDout of the gate driver. That is, in the buffer circuit 210, two inverter circuits 211 are connected in series for each output terminal SRout of the shift register circuit 200 in each stage.

The operation of the gate driver in FIG. 21 will be described for each of the case where the output terminal SRout is at the H level and the case where the output terminal SRout is at the L level.

First, the case where the output terminal SRout is at the H level will be described. Since the output terminal SRout is connected to the output terminal GDout via the two inverter circuits 211, the output terminal GDout becomes H level.

Next, the case where the output terminal SRout is at the L level will be described. Since the output terminal SRout is connected to the output terminal GDout via the two inverter circuits 211, the output terminal GDout becomes L level.

With the above operation, when the output terminal SRout becomes H level, the output terminal GDout becomes H level. Further, when the output terminal SRout becomes L level, the output terminal GDout becomes L level.

Further, since the inverter circuit 211 has a rectifying action, it is possible to suppress the noise at the output terminal SRout from affecting the output terminal GDout of the gate driver.

In the buffer circuit 210, two inverter circuits 211 are connected in series, but a plurality of inverter circuits 211 may be connected in series. For example, when an odd number of inverter circuits 211 are connected in series, the output terminal GDout has a level opposite to that of the output terminal SRout. When an even number of inverter circuits 211 are connected in series, the output terminal GDout is at the same level as the output terminal SRout.

In the buffer circuit 210, the two inverter circuits 211 are connected in series, but a plurality of inverter circuits 211 may be connected in parallel. By doing so, since the current density of the inverter circuit 211 is reduced, the characteristic deterioration of the elements constituting the inverter circuit 211 is suppressed.

FIG. 22 shows another embodiment of the gate driver including the buffer circuit of the present invention. The gate driver in FIG. 22 includes a shift register circuit 200, a buffer circuit 220, and a control signal line 222. The buffer circuit 210 has a NAND circuit 221.

As shown in the gate driver in FIG. 22, the output terminal SRout of the shift register circuit 200 is connected to the output terminal GDout of the gate driver via the buffer circuit 220.

A connection relationship of the buffer circuit 220 will be described. The input terminal IN1 of the NAND circuit 221 is connected to the control signal line 222, the input terminal IN2 is connected to the output terminal SRout of the shift register circuit 200, and the output terminal OUT is connected to the output terminal GDout of the gate driver.

The control signal line 222 is supplied with an enable signal En. The enable signal En is a digital signal.

The operation of the gate driver in FIG. 22 will be described for each of the case where the control signal line 222 is at the H level, the case where the control signal line 222 is the L level, the case where the output terminal SRout is the H level, and the case where the output terminal SRout is the L level.

First, the case where the control signal line 222 is at the H level and the output terminal SRout is at the H level will be described. The input terminal IN1 of the NAND circuit 221 becomes H level, and the input terminal IN2 becomes H level. Therefore, since the output terminal OUT of the NAND circuit 221 is at the L level, the output terminal GDout is at the L level.

Next, the case where the control signal line 222 is at the H level and the output terminal SRout is at the L level will be described. The input terminal IN1 of the NAND circuit 221 becomes H level, and the input terminal IN2 becomes L level. Therefore, since the output terminal OUT of the NAND circuit 221 is at the H level, the output terminal GDout is at the H level.

Next, a case where the control signal line 222 is at the L level and the output terminal SRout is at the H level will be described. The input terminal IN1 of the NAND circuit 221 becomes L level, and the input terminal IN2 becomes H level. Therefore, since the output terminal OUT of the NAND circuit 221 is at the H level, the output terminal GDout is at the H level.

Next, the case where the control signal line 222 is at the L level and the output terminal SRout is at the L level will be described. The input terminal IN1 of the NAND circuit 221 becomes L level, and the input terminal IN2 becomes L level. Therefore, since the output terminal OUT of the NAND circuit 221 is at the H level, the output terminal GDout is at the H level.

With the above operation, if the control signal line 222 is at the H level, the output terminal GDout is at the L level when the output terminal SRout is at the H level, and the output terminal GDout is at the H level when the output terminal SRout is at the L level. Become a level. If the control signal line 222 is at L level, the output terminal GDout becomes H level regardless of the output terminal SRout.

Thus, the output signal of the gate driver can be arbitrarily changed by the enable signal En. The gate driver in FIG. 22 can perform so-called pulse width control (PWC).

Here, the pulse width control is performed by utilizing the fact that the output terminal becomes H level regardless of the output terminal SRout when the enable signal En is at L level. In other words, even if the output signal of the shift register circuit 200 has a certain L level pulse width (cycle), the output signal can be shortened by setting the enable signal En to the L level.

Note that although the NAND circuit 221 has two input terminals, the NAND circuit 221 may have any number of input terminals as long as the output signal of the shift register circuit 200 is supplied to any one of the input terminals. If there are a plurality of input terminals of the NAND circuit 221, the buffer circuit 220 can control the output signal of the gate driver more accurately.

24, the output terminal SRout may be connected to the input terminal IN2 of the NAND circuit 221 through the inverter circuit 211. In this case, if the control signal line 222 is at the H level, the output terminal GDout is at the H level when the output terminal SRout is at the H level, and the output terminal GDout is at the L level when the output terminal SRout is at the L level. Become. If the control signal line 222 is at L level, the output terminal GDout becomes H level regardless of the output terminal SRout.

26, the output terminal OUT of the NAND circuit 221 may be connected to the output terminal GDout through the inverter circuit 211. In this case, if the control signal line 222 is at the H level, the output terminal GDout is at the H level when the output terminal SRout is at the H level, and the output terminal GDout is at the L level when the output terminal SRout is at the L level. Become. If the control signal line 222 is at the L level, the output terminal GDout is at the L level regardless of the output terminal SRout.

Note that although the enable signal En is supplied to the control signal line 222, the present invention is not limited to this.

For example, another control signal may be supplied to the control signal line 222.

As another example, power may be supplied to the control signal line 222.

FIG. 23 specifically illustrates another mode of a gate driver including the buffer circuit of the present invention. The gate driver in FIG. 23 includes a shift register circuit 200, a buffer circuit 230, and a control signal line 222. The buffer circuit 230 has a NOR circuit 231.

As shown in the gate driver in FIG. 23, the output terminal SRout of the shift register circuit 200 is connected to the output terminal GDout of the gate driver via the buffer circuit 230.

A connection relationship of the buffer circuit 230 will be described. The input terminal IN1 of the NOR circuit 231 is connected to the control signal line 222, the input terminal IN2 is connected to the output terminal SRout of the shift register circuit 200, and the output terminal OUT is connected to the output terminal GDout of the gate driver.

The control signal line 222 is supplied with an enable signal En.

The operation of the gate driver in FIG. 23 will be described for each of the case where the control signal line 222 is at the H level, the case where the control signal line 222 is the L level, the case where the output terminal SRout of the shift register circuit 200 is the H level, . .

First, the case where the control signal line 222 is at H level and the output terminal SRout of the shift register circuit 200 is at H level is described. The input terminal IN1 of the NOR circuit 231 becomes H level, and the input terminal IN2 becomes H level. Therefore, since the output terminal OUT of the NOR circuit becomes L level, the output terminal GDout becomes L level.

Next, the case where the control signal line 222 is at the H level and the output terminal SRout of the shift register circuit 200 is at the L level is described. The input terminal IN1 of the NOR circuit 231 becomes H level, and the input terminal IN2 becomes L level. Therefore, since the output terminal OUT of the NOR circuit becomes L level, the output terminal GDout becomes L level.

Next, the case where the control signal line 222 is at L level and the output terminal SRout of the shift register circuit 200 is at H level is described. The input terminal IN1 of the NOR circuit 231 becomes L level, and the input terminal IN2 becomes H level. Therefore, since the output terminal OUT of the NOR circuit becomes L level, the output terminal GDout becomes L level.

Next, a case where the control signal line 222 is at L level and the output terminal SRout of the shift register circuit 200 is at L level is described. The input terminal IN1 of the NOR circuit 231 becomes L level, and the input terminal IN2 becomes L level. Therefore, since the output terminal OUT of the NOR circuit becomes H level, the output terminal GDout becomes H level.

With the above operation, if the control signal line 222 is at the H level, the output terminal GDout becomes the L level regardless of the output terminal SRout. If control signal line 222 is at L level, output terminal GDout is at L level when output terminal SRout is at H level, and output terminal GDout is at H level when output terminal SRout is at L level.

Thus, the output terminal GDout of the gate driver can be arbitrarily changed by the enable signal En. The gate driver in FIG. 22 can perform so-called pulse width control (PWC).

Here, the pulse width control can be performed by utilizing the fact that the output terminal becomes L level regardless of the output terminal SRout when the enable signal En is at H level. In other words, even if the output signal of the shift register circuit 200 has a certain H level pulse width (cycle), the output signal can be shortened by setting the enable signal En to the H level.

Although the NOR circuit 231 has two input terminals, the NOR circuit 231 may have any number of input terminals as long as the output signal of the shift register circuit 200 is supplied to any one of the input terminals. If there are a plurality of input terminals of the NOR circuit 231, the buffer circuit 230 can control the output signal of the gate driver more accurately.

25, the output terminal SRout of the shift register circuit 200 may be connected to the input terminal IN2 of the NOR circuit 231 through the inverter circuit 211. In this case, if the control signal line 222 is at the H level, the output terminal GDout is at the H level regardless of the output terminal SRout. If control signal line 222 is at L level, output terminal GDout is at H level when output terminal SRout is at H level, and output terminal GDout is at L level when output terminal SRout is at L level.

27, the output terminal OUT of the NOR circuit 231 may be connected to the output terminal GDout of the gate driver via the inverter circuit 211. In this case, if the control signal line 222 is at the H level, the output terminal GDout is at the L level regardless of the output terminal SRout. If control signal line 222 is at L level, output terminal GDout is at H level when output terminal SRout is at H level, and output terminal GDout outputs an L level signal when output terminal SRout is at L level. To do.

Here, a configuration example applicable to the inverter circuit 211 will be described.

FIG. 28 illustrates one mode of the inverter circuit 211. The inverter circuit 280 in FIG. 28 includes a transistor 281 and a transistor 282.

As shown in the inverter circuit 280 in FIG. 28, the first terminal of the transistor 281 is connected to the second power supply, the second terminal is connected to the second terminal of the transistor 282, and the output terminal OUT, and the gate terminal is the input terminal. Connected to IN. A first terminal of the transistor 282 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VDD is supplied to the first power supply, and the power supply potential VSS is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VDD of the first power supply and the power supply potential VSS of the second power supply corresponds to the power supply voltage of the inverter circuit 280. The power supply potential VDD is higher than the power supply potential VSS.

Note that a digital control signal is supplied to the input terminal IN. The output terminal OUT outputs an output signal.

Further, the transistor 281 and the transistor 282 are each an N-channel type.

The operation of the inverter circuit 280 in FIG. 28 will be described for each of the case where the input terminal IN is at the H level and the case where the input terminal IN is at the L level.

First, the case where the input terminal IN is at the H level will be described. When the input terminal IN becomes H level, the transistor 281 is turned on. The output terminal OUT is electrically connected to the second power supply through the transistor 281 and is electrically connected to the first power supply through the transistor 282, so that the potential of the output terminal OUT decreases. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 281 and the transistor 282, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN is at the L level will be described. When the input terminal IN becomes L level, the transistor 281 is turned off. The output terminal OUT is electrically connected to the first power supply through the transistor 282, and the potential of the output terminal OUT rises. At this time, the potential of the output terminal OUT becomes a value obtained by subtracting the threshold potential Vth282 of the transistor 282 from the power supply potential VDD (VDD−Vth282), and the output terminal OUT becomes H level.

Note that the transistor 282 does not need to have rectifying properties, and various elements can be used as long as a voltage is generated when a current flows. For example, a resistor 321 may be connected instead of the transistor 282 as in the inverter circuit 320 in FIG.

Here, functions of the transistor 281 and the transistor 282 are described below.

The transistor 281 functions as a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN. When the input terminal IN is at an H level, the transistor 281 has a function of supplying the power supply potential VSS to the output terminal OUT.

The transistor 282 functions as a diode.

FIG. 29 shows another mode of the inverter circuit 211. An inverter circuit 290 in FIG. 29 includes a transistor 291, a transistor 292, a transistor 293, and a capacitor 294 having two electrodes. Note that the capacitor 294 is not necessarily required.

As shown in the inverter circuit 290 in FIG. 29, the first terminal of the transistor 291 is connected to the second power source, the second terminal is connected to the second terminal of the transistor 292, the second electrode of the capacitor 294, and the output terminal OUT. The gate terminal is connected to the input terminal IN. A first terminal of the transistor 292 is connected to the first power supply, and a gate terminal is connected to the second terminal of the transistor 293 and the first electrode of the capacitor 294. A first terminal of the transistor 293 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN, and the output terminal OUT can be the same as those in FIG.

In addition, each of the transistors 291 to 293 is an N-channel type.

The operation of the inverter circuit 290 in FIG. 29 will be described for each of the case where the input terminal IN is at the H level and the case where the input terminal IN is at the L level.

First, the case where the input terminal IN is at the H level will be described. When the input terminal IN becomes H level, the transistor 291 is turned on. The potential of the gate terminal of the transistor 292 is a value obtained by subtracting the threshold potential Vth293 of the transistor 293 from the power supply potential VDD (VDD−Vth293), and the transistor 292 is on. Further, the gate terminal of the transistor 292 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply via the transistor 291 and the first power supply is electrically connected to the output terminal OUT via the transistor 292, so that the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 291 and the transistor 292, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN is at the L level will be described. When the input terminal IN becomes L level, the transistor 291 is turned off. The potential of the gate terminal of the transistor 292 is a value obtained by subtracting the threshold potential Vth293 of the transistor 293 from the power supply potential VDD (VDD−Vth293), and the transistor 292 is on. Further, the gate terminal of the transistor 292 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 292, and the potential of the output terminal OUT is increased. The potential of the gate terminal of the transistor 292 rises to a value equal to or higher than the sum of the power supply potential VDD and the threshold potential Vth292 of the transistor 292 due to capacitive coupling of the capacitor 294, and the transistor 292 continues to be turned on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VDD, and the output terminal OUT becomes H level.

In this manner, in the inverter circuit 290 in FIG. 29, the potential of the H-level output terminal OUT can be raised to the power supply potential VDD of the first power supply by the bootstrap operation.

Note that the inverter circuit 290 in FIG. 29 is not limited to the circuit configuration in FIG. 29 as long as the bootstrap operation can be performed when the input terminal IN is at an L level. When the input terminal IN is at an H level, a potential may be supplied to the gate terminal of the transistor 292.

For example, a transistor 331 may be added as in the inverter circuit 330 in FIG. This is because the potential of the output terminal OUT can be set to VSS when the output terminal OUT is at the L level. That is, when the input terminal IN is at the H level, the transistor 331 is turned on, so that the gate terminal of the transistor 292 is at the L level. This is because the transistor 292 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 291.

Note that the transistor 331 is an n-channel transistor.

As another example, the first terminal of the transistor 293 may be connected to the input terminal INb as in the inverter circuit 360 in FIG. This is because the potential of the output terminal OUT can be set to VSS when the output terminal OUT is at the L level. That is, when the input terminal IN is at the H level, the input terminal INb is at the L level, so that the gate terminal of the transistor 292 is at the L level. This is because the transistor 292 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 291.

Note that an inverted signal of the signal of the input terminal IN is supplied to the input terminal INb. A method for generating a signal supplied to the input terminal INb will be described.

For example, as shown in FIG. 124, the signal of the input terminal IN may be supplied to the input terminal INb via an inverter circuit 1241. Further, the inverter circuit described in FIGS. 28 to 35 can be applied to the inverter circuit 1241.

Note that the input terminal INb is not necessarily supplied with an inverted signal of the signal of the input terminal IN. A signal supplied to the input signal INb will be described.

For example, when the input terminal IN is connected to the nth output terminal SRoutn, the input terminal INb may be connected to the (n−1) th output terminal SRoutn−1.

As another example, when the input terminal IN is connected to the n-th stage output terminal SRoutn, the input terminal INb may be connected to the (n + 1) -th stage output terminal SRoutn + 1.

As another example, when the input terminal IN is connected to the n-th output terminal SRout, the input terminal INb may be connected to the node N2 of the n-th flip-flop circuit. This is because the potential of the node N2 of the flip-flop circuit is inverted with respect to the potential of the output terminal SRout in the non-selection period, and thus the potential of the node N2 of the flip-flop circuit can be used as an inverted signal. Therefore, by supplying the potential of the node N2 of the flip-flop circuit to the input terminal INb of the inverter circuit 360, an inverter circuit for generating an inverted signal can be eliminated.

As another example, if a control signal (digital value) is supplied to the input terminal INb, the inverter circuit in FIG. 36 can operate as a tristate buffer circuit. This is because when the input terminal IN is at the L level and the input terminal INb is at the L level, the transistor 291 and the transistor 292 are turned off, so that the output terminal OUT is not connected to any power source. Therefore, the inverter circuit 360 can have a function as a tristate buffer circuit or an inverter circuit.

Thus, a signal can be supplied to the input terminal INb of the inverter circuit 360 by various methods.

Hereinafter, the application example of FIG. 29 will be described again.

As another example, as in the inverter circuit 390 in FIG. 39, the first terminal and the gate terminal of the transistor 293 may be connected to the input terminal INb, and the transistor 391 may be added. This is because the potential of the output terminal OUT can be set to VSS when the output terminal OUT is at the L level. That is, when the input terminal INb is at the L level, the gate terminal of the transistor 292 is at the L level. This is because the transistor 292 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 291.

Note that a variety of capacitors can be used as the capacitor 294 as long as it has capacitance. For example, instead of the capacitor 294, a transistor 301, a transistor 341, a transistor 371, an inverter circuit 300 in FIG. 30, an inverter circuit 340 in FIG. 34, an inverter circuit 370 in FIG. 37, and an inverter circuit 400 in FIG. The transistor 401 may be connected.

Note that the capacitor 294 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 292 is sufficiently large. For example, the capacitor 294 is not necessarily connected as in the inverter circuit 310 in FIG. 31, the inverter circuit 350 in FIG. 35, the inverter circuit 380 in FIG. 38, and the inverter circuit 410 in FIG.

Here, functions of the transistors 291 to 293, the transistor 301, the transistor 331, the transistor 341, and the capacitor 294 are described below.

The transistor 291 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN. When the input terminal IN is at an H level, the transistor 291 has a function of supplying the power supply potential VSS to the output terminal OUT.

The transistor 292 functions as a switch that selects whether to connect the first power source and the output terminal OUT.

The transistor 293 functions as a diode. The transistor 293 has a function of bringing the gate terminal of the transistor 292 into a floating state.

The transistor 301 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 292. When the input terminal IN is at an L level, the transistor 301 has a function of increasing the potential of the gate terminal of the transistor 292.

The transistor 331 functions as a switch for selecting whether or not to connect the second power supply and the gate terminal of the transistor 292 depending on the potential of the input terminal IN.

The transistor 341 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 292. When the input terminal IN is at the L level, the capacitor 341 has a function of increasing the potential of the gate terminal of the transistor 292 by increasing the potential of the output terminal OUT.

The capacitor 294 has a function of changing the potential of the gate terminal of the transistor 292 in accordance with the potential of the output terminal OUT. When the input terminal IN is at an L level, the capacitor 294 has a function of increasing the potential of the gate terminal of the transistor 292 by increasing the potential of the output terminal OUT.

As described above, when the inverter circuits in FIGS. 28 to 41 output an H level signal, the potential of the output terminal OUT can be freely changed by changing the power supply potential VDD. That is, the inverter circuits of FIGS. 28 to 41 can operate not only as an inverter circuit but also as a level shift circuit.

In the inverter circuits of FIGS. 28 to 41, the case where all are configured by N-channel transistors has been described, but all may be configured by P-channel transistors. Here, FIG. 58 to FIG. 71 show inverter circuits in the case where they are all constituted by P-channel transistors.

FIG. 58 shows one mode of the inverter circuit 211. The inverter circuit 580 in FIG. 58 includes a transistor 581 and a transistor 582.

As shown in the inverter circuit 580 in FIG. 58, the first terminal of the transistor 581 is connected to the second power supply, the second terminal is connected to the second terminal of the transistor 582 and the output terminal OUT, and the gate terminal is the input terminal. Connected to IN. A first terminal of the transistor 582 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VSS is supplied to the first power supply, and the power supply potential VDD is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VSS of the first power supply and the power supply potential VDD of the second power supply corresponds to the power supply voltage of the inverter circuit 580. The power supply potential VDD is higher than the power supply potential VSS.

Note that a digital control signal is supplied to the input terminal IN. The output terminal OUT outputs an output signal.

Further, the transistor 581 and the transistor 582 are each a P-channel type.

The operation of the inverter circuit 580 in FIG. 58 will be described for each of the case where the input terminal IN is at the H level and the case where the input terminal IN is at the L level.

First, the case where the input terminal IN is at H level will be described. When the input terminal IN becomes H level, the transistor 581 is turned off. The output terminal OUT is electrically connected to the first power supply through the transistor 582, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT becomes a value (VSS + | Vth582 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth582 of the transistor 582, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN is at the L level will be described. When the input terminal IN becomes L level, the transistor 581 is turned on. The output terminal OUT is electrically connected to the second power supply via the transistor 581 and is electrically connected to the first power supply via the transistor 582, so that the potential of the output terminal OUT rises. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 581 and the transistor 582, and the output terminal OUT becomes H level.

Note that the transistor 582 does not need to have rectifying properties, and various elements can be used as long as a voltage is generated when a current flows. For example, a resistance element 621 may be connected instead of the transistor 582 as in the inverter circuit 620 in FIG.

Here, functions of the transistor 581 and the transistor 582 are described below.

The transistor 581 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN. When the input terminal IN is at an L level, the transistor 581 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 582 functions as a diode.

FIG. 59 shows another mode of the inverter circuit 211. An inverter circuit 590 in FIG. 59 includes a transistor 591, a transistor 592, a transistor 593, and a capacitor 594 having two electrodes. Note that the capacitor 594 is not necessarily required.

As shown in the inverter circuit 590 in FIG. 59, the first terminal of the transistor 591 is connected to the second power supply, the second terminal is connected to the second terminal of the transistor 592, the second electrode of the capacitor 594, and the output terminal OUT. The gate terminal is connected to the input terminal IN. A first terminal of the transistor 592 is connected to the first power supply, and a gate terminal is connected to the second terminal of the transistor 593 and the first electrode of the capacitor 594. A first terminal of the transistor 593 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN, and the output terminal OUT can be the same as those in FIG.

In addition, the transistors 591 to 593 are each P-channel type.

The operation of the inverter circuit 590 in FIG. 59 will be described for each of the case where the input terminal IN is at the H level and the case where the input terminal IN is at the L level.

First, the case where the input terminal IN is at H level will be described. When the input terminal IN becomes H level, the transistor 591 is turned off. The potential of the gate terminal of the transistor 592 is a value (VSS + | Vth593 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth593 of the transistor 593, and the transistor 592 is on. Further, the gate terminal of the transistor 592 is in a floating state.

Accordingly, the output terminal OUT is brought into conduction with the first power supply through the transistor 592 and the potential of the output terminal OUT is lowered. The potential of the gate terminal of the transistor 592 is reduced to a value less than (VSS− | Vth592 |) obtained by subtracting the absolute value | Vth592 | of the threshold potential Vth592 of the transistor 592 from the power supply potential VSS due to capacitive coupling of the capacitor 594. 592 keeps on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VSS, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN is at L level will be described. When the input terminal IN becomes L level, the transistor 591 is turned on. The potential of the gate terminal of the transistor 592 is a value (VSS + | Vth593 |) which is the sum of the power supply potential VSS and the absolute value | Vth593 | of the threshold potential of the transistor 593, and the transistor 592 is on. Further, the gate terminal of the transistor 592 is in a floating state.

Accordingly, the output terminal OUT is electrically connected to the second power supply via the transistor 591 and the first power supply is electrically connected to the output terminal OUT via the transistor 592, so that the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 591 and the transistor 592, and the output terminal OUT becomes H level.

As described above, in the inverter circuit 590 in FIG. 59, the potential of the L-level output terminal OUT can be lowered to the power supply potential VSS of the first power supply by the bootstrap operation.

Note that the inverter circuit 590 in FIG. 59 is not limited to the circuit configuration in FIG. 59 as long as the bootstrap operation can be performed when the input terminal IN is at an H level. When the input terminal IN is at an L level, a potential may be supplied to the gate terminal of the transistor 592.

For example, a transistor 631 may be added as in the inverter circuit 630 in FIG. This is because the potential of the output terminal OUT can be set to VDD when the output terminal OUT is at the H level. That is, since the transistor 631 is turned on when the input terminal IN is at the L level, the gate terminal of the transistor 592 becomes the H level. This is because the transistor 592 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 591.

Note that the transistor 631 is a P-channel type.

As another example, the first terminal of the transistor 593 may be connected to the input terminal INb as in the inverter circuit 660 in FIG. This is because the potential of the output terminal OUT can be set to VDD when the output terminal OUT is at the H level. That is, when the input terminal IN is at the L level, the input terminal INb is at the H level, so that the gate terminal of the transistor 592 is at the H level. This is because the transistor 592 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 591.

Note that an inverted signal of the signal of the input terminal IN is supplied to the input terminal INb. Further, the same one as the input terminal INb in FIG. 36 can be used.

For example, as shown in FIG. 125, the signal of the input terminal IN may be supplied to the input terminal INb via an inverter circuit 1251. As the inverter circuit 1251, the inverter circuit described with reference to FIGS. 58 to 65 can be used.

FIG. 36 shows that the inverter circuit 360 also functions as a tristate buffer circuit by supplying a control signal to the input terminal INb. Here, the inverter circuit 660 of FIG. 66 can also function as a tristate buffer circuit by supplying a control signal to the input terminal INb. In other words, when the input terminal IN is at the H level and the input terminal INb is at the H level, the transistor 591 and the transistor 592 are turned off, so that the output terminal OUT is not connected to any power source, so that the inverter circuit 660 serves as a tristate buffer circuit. Can function.

Hereinafter, the application example of FIG. 59 will be described again.

As another example, as in the inverter circuit 690 in FIG. 69, the first terminal and gate terminal of the transistor 593 may be connected to the input terminal INb, and the transistor 631 may be added. This is because the potential of the output terminal OUT can be set to VDD when the output terminal OUT is at the H level. That is, when the input terminal INb is at the H level, the gate terminal of the transistor 592 is at the H level. This is because the transistor 592 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 591.

Note that a variety of capacitors can be used as the capacitor 594 as long as it has capacitance. For example, as in the inverter circuit 600 in FIG. 60, the inverter circuit 640 in FIG. 64, the inverter circuit 670 in FIG. 67, and the inverter circuit 700 in FIG. 70, a transistor 601, a transistor 641, a transistor 671, A transistor 701 may be connected.

Note that the capacitor 594 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 592 is sufficiently large. For example, as in the inverter circuit 610 in FIG. 61, the inverter circuit 650 in FIG. 65, the inverter circuit 680 in FIG. 68, and the inverter circuit 710 in FIG.

Here, functions of the transistors 591 to 593, the transistor 601, the transistor 631, the transistor 641, and the capacitor 594 are described below.

The transistor 591 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN. When the input terminal IN is at an L level, the transistor 591 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 592 functions as a switch for selecting whether or not to connect the first power supply and the output terminal OUT.

The transistor 593 functions as a diode. The transistor 593 has a function of bringing the gate terminal of the transistor 592 into a floating state.

The transistor 601 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 592. When the input terminal IN is at an H level, the transistor 601 has a function of decreasing the potential of the gate terminal of the transistor 592.

The transistor 631 functions as a switch for selecting whether or not to connect the second power supply and the gate terminal of the transistor 592 depending on the potential of the input terminal IN. When the input terminal IN is at an L level, the transistor 631 has a function of supplying the power supply potential VDD to the gate terminal of the transistor 592.

The transistor 641 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 592. When the input terminal IN is at an L level, the capacitor 594 has a function of increasing the potential of the gate terminal of the transistor 592 by increasing the potential of the output terminal OUT.

The capacitor 594 has a function of changing the potential of the gate terminal of the transistor 592 in accordance with the potential of the output terminal OUT. When the input terminal IN is at the H level, the capacitor 594 has a function of decreasing the potential of the gate terminal of the transistor 592 by increasing the potential of the output terminal OUT.

As described above, the inverter circuits in FIGS. 58 to 71 can freely change the potential of the output terminal OUT by changing the power supply potential VSS when outputting the L level signal. That is, the inverter circuits of FIGS. 58 to 71 can operate not only as an inverter circuit but also as a level shift circuit.

Here, some configuration examples applicable to the NAND circuit 221 are described.

FIG. 42 illustrates one mode of the NAND circuit 221. A NAND circuit 420 in FIG. 42 includes a transistor 421, a transistor 422, and a transistor 423.

As shown in the NAND circuit 420 of FIG. 42, the first terminal of the transistor 421 is connected to the second power supply, the second terminal is connected to the first terminal of the transistor 422, and the gate terminal is connected to the input terminal IN1. Yes. A second terminal of the transistor 422 is connected to the first terminal of the transistor 423 and the output terminal OUT, and a gate terminal is connected to the input terminal IN2. A second terminal of the transistor 423 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VDD is supplied to the first power supply, and the power supply potential VSS is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VDD of the first power supply and the power supply potential VSS of the second power supply corresponds to the power supply voltage of the NAND circuit 420. The power supply potential VDD is higher than the power supply potential VSS.

A digital control signal is supplied to each of the input terminal IN1 and the input terminal IN2. The output terminal OUT outputs an output signal.

In addition, each of the transistors 421 to 423 is an N-channel type.

The operation of the NAND circuit 420 in FIG. 42 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the L level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the L level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 is at H level, the transistor 421 is turned on. When the input terminal IN2 becomes H level, the transistor 422 is turned on.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 421 and the transistor 422, and is electrically connected to the first power supply through the transistor 423, so that the potential of the output terminal OUT is decreased. At this time, the potential of the output terminal OUT is determined by operating points of the transistor 421, the transistor 422, and the transistor 423, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 is at H level, the transistor 421 is turned on. When the input terminal IN2 becomes L level, the transistor 422 is turned off.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 423, and the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT becomes a value obtained by subtracting the threshold potential Vth423 of the transistor 423 from the power supply potential VDD (VDD−Vth423), and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 421 is turned off. When the input terminal IN2 becomes H level, the transistor 422 is turned on.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 423, and the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT becomes a value obtained by subtracting the threshold potential Vth423 of the transistor 423 from the power supply potential VDD (VDD−Vth423), and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 421 is turned off. When the input terminal IN2 becomes L level, the transistor 422 is turned off.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 423, and the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT becomes a value obtained by subtracting the threshold potential Vth423 of the transistor 423 from the power supply potential VDD (VDD−Vth423), and the output terminal OUT becomes H level.

Note that the transistor 423 does not need to have rectifying properties, and various elements can be used as long as a voltage is generated when a current flows. For example, a resistance element 461 may be connected instead of the transistor 423 as in the NAND circuit 460 in FIG.

Here, functions of the transistors 421 to 423 are described below.

The transistor 421 functions as a switch that selects whether or not to connect the second power supply and the first terminal of the transistor 422 in accordance with the potential of the input terminal IN1.

The transistor 422 functions as a switch for selecting whether or not to connect the second terminal of the transistor 421 and the output terminal OUT in accordance with the potential of the input terminal IN2.

The transistor 423 functions as a diode.

FIG. 43 illustrates one mode of the NAND circuit 221. A NAND circuit 430 in FIG. 43 includes a transistor 431, a transistor 432, a transistor 433, a transistor 434, and a capacitor 435.

As shown in the NAND circuit 430 of FIG. 43, the first terminal of the transistor 431 is connected to the second power supply, the second terminal is connected to the first terminal of the transistor 432, and the gate terminal is connected to the input terminal IN1. Yes. The second terminal of the transistor 432 is connected to the second terminal of the transistor 433, the second electrode of the capacitor 435, and the output terminal OUT, and the gate terminal is connected to the input terminal IN2. A first terminal of the transistor 433 is connected to the first power supply, and a gate terminal is connected to the second terminal of the transistor 434 and the first electrode of the capacitor 435. A first terminal of the transistor 434 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN1, the input terminal IN2, and the output terminal OUT can be the same as those in FIG.

In addition, the transistors 431 to 434 are each an N-channel type.

The operation of the NAND circuit 430 in FIG. 43 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the H level.

First, the case where the input terminal IN is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 431 is turned on. When the input terminal IN2 becomes H level, the transistor 432 is turned on. The potential of the gate terminal of the transistor 433 is a value obtained by subtracting the threshold potential Vth434 of the transistor 434 from the power supply potential VDD (VDD−Vth434), and the transistor 433 is on.

Therefore, the output terminal OUT is electrically connected to the second power supply via the transistor 431 and the transistor 432, and is electrically connected to the first power supply via the transistor 433, so that the potential of the output terminal OUT is lowered. The potential of the output terminal OUT at this time is determined by operating points of the transistor 431, the transistor 432, and the transistor 433, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes H level, the transistor 431 is turned on. When the input terminal IN2 becomes L level, the transistor 432 is turned off. The potential of the gate terminal of the transistor 433 is a value obtained by subtracting the threshold potential Vth434 of the transistor 434 from the power supply potential VDD (VDD−Vth434), and the transistor 433 is on. In addition, the gate terminal of the transistor 433 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 433, and the potential of the output terminal OUT is increased. The potential of the gate terminal of the transistor 433 rises to a value equal to or higher than the sum of the power supply potential VDD and the threshold potential Vth433 of the transistor 433 due to capacitive coupling of the capacitor 435, and the transistor 433 continues to be turned on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VDD, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 431 is turned off. When the input terminal IN2 becomes H level, the transistor 432 is turned on. The potential of the gate terminal of the transistor 433 is a value obtained by subtracting the threshold potential Vth434 of the transistor 434 from the power supply potential VDD (VDD−Vth434), and the transistor 433 is on. In addition, the gate terminal of the transistor 433 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 433, and the potential of the output terminal OUT is increased. The potential of the gate terminal of the transistor 433 rises to a value equal to or higher than the sum of the power supply potential VDD and the threshold potential Vth 433 of the transistor 433 due to capacitive coupling of the capacitor 435, and the transistor 433 continues to be turned on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VDD, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 431 is turned off. When the input terminal IN2 becomes L level, the transistor 432 is turned off. The potential of the gate terminal of the transistor 433 is a value obtained by subtracting the threshold potential Vth434 of the transistor 434 from the power supply potential VDD (VDD−Vth434), and the transistor 433 is on. Further, the gate terminal of the transistor 433 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 433, and the potential of the output terminal OUT is increased. The potential of the gate terminal of the transistor 433 rises to a value equal to or higher than the sum of the power supply potential VDD and the threshold potential Vth 433 of the transistor 433 due to capacitive coupling of the capacitor 435, and the transistor 433 continues to be turned on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VDD, and the output terminal OUT becomes H level.

As described above, in the NAND circuit 430 in FIG. 43, the potential of the H-level output terminal OUT can be raised to the power supply potential VDD of the first power supply by the bootstrap operation.

Note that the NAND circuit 430 in FIG. 43 is not limited to the circuit configuration in FIG. 43 as long as the bootstrap operation can be performed when the input terminal IN1 or the input terminal IN2 is at the L level. When the input terminal IN1 and the input terminal IN2 are at the H level, a potential may be supplied to the gate terminal of the transistor 433.

For example, a transistor 471 and a transistor 472 may be added as in the NAND circuit 470 in FIG. This is because the potential of the output terminal OUT can be set to VSS when the output terminal OUT is at the L level. That is, when the input terminal IN1 and the input terminal IN2 are at the H level, the transistor 471 and the transistor 472 are turned on, so that the gate terminal of the transistor 433 is at the L level. This is because the transistor 433 is turned off and the output terminal OUT is brought into conduction only with the second power supply through the transistor 431 and the transistor 432.

Note that each of the transistor 471 and the transistor 472 is an N-channel type.

Note that a variety of capacitors can be used as the capacitor 435 as long as it has capacitance. For example, as in the NAND circuit 440 in FIG. 44 and the NAND circuit 480 in FIG. 48, a transistor 441 and a transistor 481 may be connected instead of the capacitor 435, respectively.

Note that the capacitor 435 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 433 is sufficiently large. For example, as in the NAND circuit 450 in FIG. 45 and the NAND circuit 490 in FIG. 49, the capacitor 435 may not be connected.

Here, functions of the transistors 431 to 434, the transistor 441, the transistor 471, the transistor 472, the transistor 481, and the capacitor 435 are described below.

The transistor 431 functions as a switch that selects whether or not to connect the second power supply and the first terminal of the transistor 432 depending on the potential of the input terminal IN1.

The transistor 432 functions as a switch that selects whether or not to connect the second terminal of the transistor 432 and the output terminal OUT in accordance with the potential of the input terminal IN2.

The transistor 433 functions as a switch that selects whether to connect the first power supply and the output terminal OUT.

The transistor 434 functions as a diode. The transistor 434 has a function of bringing the gate terminal of the transistor 433 into a floating state.

The transistor 441 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 433. The transistor 441 has a function of increasing the potential of the gate terminal of the transistor 433 when the input terminal IN1 or the input terminal IN2 is at an L level.

The transistor 471 functions as a switch that selects whether to connect the second power supply and the first terminal of the transistor 472 in accordance with the potential of the input terminal IN1.

The transistor 472 functions as a switch that selects whether or not to connect the first terminal of the transistor 471 and the gate terminal of the transistor 433 in accordance with the potential of the input terminal IN2.

The transistor 481 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 433. The transistor 441 has a function of increasing the potential of the gate terminal of the transistor 433 when the input terminal IN1 or the input terminal IN2 is at an L level.

The capacitor 435 has a function of changing the potential of the gate terminal of the transistor 433 in accordance with the potential of the output terminal OUT. When the input terminal IN1 or the input terminal IN2 is at an L level, the capacitor 435 has a function of increasing the potential of the gate terminal of the transistor 433.

As described above, the NAND circuits in FIGS. 42 to 49 can freely change the potential of the output terminal OUT by changing the power supply potential VDD when outputting an H level signal. That is, the NAND circuits in FIGS. 42 to 49 can operate not only as NAND circuits but also as level shift circuits.

In the NAND circuits of FIGS. 42 to 49, the case where all of the NAND circuits are configured by N-channel type transistors has been described. However, all of the NAND circuits may be configured by P-channel type transistors. Here, FIGS. 80 to 87 show NAND circuits in the case where they are all formed of P-channel transistors.

FIG. 80 shows another mode of the NAND circuit 221. A NAND circuit 800 in FIG. 80 includes a transistor 801, a transistor 802, and a transistor 803.

As shown in the NAND circuit 800 in FIG. 80, the first terminal of the transistor 801 is connected to the second power supply, and the second terminal is connected to the second terminal of the transistor 802, the second terminal of the transistor 803, and the output terminal OUT. The gate terminal is connected to the input terminal IN1. A first terminal of the transistor 802 is connected to the second power supply, and a gate terminal is connected to the input terminal IN2. A first terminal of the transistor 803 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VSS is supplied to the first power supply, and the power supply potential VDD is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VSS of the first power supply and the power supply potential VDD of the second power supply corresponds to the power supply voltage of the NAND circuit 800. The power supply potential VDD is higher than the power supply potential VSS.

A digital control signal is supplied to each of the input terminal IN1 and the input terminal IN2. The output terminal OUT outputs an output signal.

The transistors 801 to 803 are each a P-channel type.

The operation of the NAND circuit 800 in FIG. 80 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the L level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the L level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 is at an H level, the transistor 801 is turned off. When the input terminal IN2 becomes H level, the transistor 802 is turned off.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 803, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT becomes a value (VSS + | Vth803 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth803 of the transistor 803, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 is at an H level, the transistor 801 is turned off. When the input terminal IN2 becomes L level, the transistor 802 is turned on.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 802 and the first power supply is connected to the output terminal OUT through the transistor 803, so that the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by the operating point of the transistors 802 and 803, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 801 is turned on. When the input terminal IN2 becomes H level, the transistor 802 is turned off.

Accordingly, the output terminal OUT is electrically connected to the second power supply through the transistor 801 and the first power supply is connected to the output terminal OUT through the transistor 803, so that the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by the operating point of the transistors 801 and 803, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 801 is turned on. When the input terminal IN2 becomes L level, the transistor 802 is turned on.

Accordingly, the output terminal OUT is electrically connected to the second power supply through the transistor 801, the second power supply is connected to the output terminal OUT via the transistor 802, and the first power supply is connected to the transistor 803, so that the potential of the output terminal OUT is increased. . At this time, the potential of the output terminal OUT is determined by operating points of the transistor 801, the transistor 802, and the transistor 803, and the output terminal OUT becomes H level.

Note that the transistor 803 does not need to have rectifying properties, and various elements can be used as long as a voltage is generated when a current flows. For example, a resistance element 841 may be connected instead of the transistor 803 as in the NAND circuit 840 in FIG.

Here, functions of the transistors 801 to 803 are described below.

The transistor 801 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN1. When the input terminal IN1 is at an L level, the transistor 801 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 802 functions as a switch that selects whether to connect the second power source and the output terminal OUT in accordance with the potential of the input terminal IN2. When the input terminal IN2 is at an L level, the transistor 802 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 803 functions as a diode.

FIG. 81 shows another mode of the NAND circuit 221. A NAND circuit 810 in FIG. 81 includes a transistor 811, a transistor 812, a transistor 813, a transistor 814, and a capacitor 815.

As shown in the NAND circuit 810 in FIG. 81, the first terminal of the transistor 811 is connected to the second power supply, the second terminal is the second terminal of the transistor 812, the second terminal of the transistor 813, and the first terminal of the capacitor 815. The gate terminal is connected to the input terminal IN1. A first terminal of the transistor 812 is connected to the second power supply, and a gate terminal is connected to the input terminal IN2. A first terminal of the transistor 813 is connected to the first power supply, and a gate terminal is connected to the second terminal of the transistor 814 and the second electrode of the capacitor 815. A first terminal of the transistor 814 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN1, the input terminal IN2, and the output terminal OUT can be the same as those in FIG.

The transistors 811 to 814 are each a P-channel type.

The operation of the NAND circuit 810 in FIG. 81 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the H level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 811 is turned off. When the input terminal IN2 is at an H level, the transistor 812 is turned off. The potential of the gate terminal of the transistor 813 is a value (VSS + | Vth814 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth814 of the transistor 814, and the transistor 813 is on. Further, the gate terminal of the transistor 813 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 813, and the potential of the output terminal OUT is lowered. The potential of the gate terminal of the transistor 813 is lowered to a value obtained by subtracting the absolute value of the threshold potential Vth813 of the transistor 813 from the power supply potential VSS due to capacitive coupling of the capacitor 815 (VSS− | Vth813 |), and the transistor 813 is turned on. Keep doing. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VSS, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes H level, the transistor 811 is turned off. When the input terminal IN2 becomes L level, the transistor 812 is turned on. The potential of the gate terminal of the transistor 813 is a value (Vss + | Vth814 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth814 of the transistor 814, and the transistor 813 is on. Further, the gate terminal of the transistor 813 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 812 and is electrically connected to the first power supply through the transistor 813, so that the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 812 and the transistor 813, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 811 is turned on. When the input terminal IN2 is at an H level, the transistor 812 is turned off. The potential of the gate terminal of the transistor 813 is a value (Vss + | Vth814 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth814 of the transistor 814, and the transistor 813 is on. Further, the gate terminal of the transistor 813 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply via the transistor 811 and is electrically connected to the first power supply via the transistor 813, so that the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by the operating point of the transistor 811 and the transistor 813, and the output terminal OUT becomes H level.

Next, the case where the input terminal IN is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 811 is turned on. When the input terminal IN2 becomes L level, the transistor 812 is turned on. The potential of the gate terminal of the transistor 813 is a value (Vss + | Vth814 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth814 of the transistor 814, and the transistor 813 is on. Further, the gate terminal of the transistor 813 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply via the transistor 811, the second power supply is electrically connected to the transistor 812, and the first power supply is electrically connected to the output terminal OUT via the transistor 813. To do. At this time, the potential of the output terminal OUT is determined by operating points of the transistor 811, the transistor 812, and the transistor 813, and the output terminal OUT becomes H level.

In this manner, in the NAND circuit 810 in FIG. 81, the potential of the L-level output terminal OUT can be lowered to the power supply potential VSS of the first power supply by the bootstrap operation.

Note that the NAND circuit 810 in FIG. 81 is not limited to the circuit configuration in FIG. 81 as long as the bootstrap operation can be performed when the input terminal IN1 and the input terminal IN2 are at the H level. When the input terminal IN1 or the input terminal IN2 is at an L level, a potential may be supplied to the gate terminal of the transistor 813.

For example, a transistor 851 and a transistor 852 may be added as in the NAND circuit 850 in FIG. This is because the potential of the output terminal OUT can be set to VDD when the output terminal OUT is at the H level. That is, when the input terminal IN1 or the input terminal IN2 is at the L level, the transistor 851 or the transistor 852 is turned on, so that the gate terminal of the transistor 813 is at the H level. This is because the transistor 813 is turned off and the output terminal OUT is brought into conduction only with the second power supply through the transistor 811 or the transistor 812.

Note that each of the transistors 851 and 852 is a P-channel type.

Note that a variety of elements can be used for the capacitor 815 as long as it has capacitance. For example, as in the NAND circuit 820 in FIG. 82 and the NAND circuit 860 in FIG. 86, a transistor 821 and a transistor 861 may be connected instead of the capacitor 815, respectively.

Note that the capacitor 815 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 813 is sufficiently large. For example, as in the NAND circuit 830 in FIG. 83 and the NAND circuit 870 in FIG. 87, the capacitor 815 is not necessarily connected.

Here, functions of the transistors 811 to 814, the transistor 821, the transistor 851, the transistor 452, the transistor 861, and the capacitor 815 are described below.

The transistor 811 functions as a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN1. When the input terminal IN1 is at the L level, the transistor 811 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 812 has a function of a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN2. When the input terminal IN2 is at an L level, the transistor 812 has a function of supplying the power supply potential VDD to the output terminal OUT.

The transistor 813 functions as a switch that selects whether to connect the first power supply and the output terminal OUT.

The transistor 814 functions as a diode. The transistor 814 has a function of bringing the gate terminal of the transistor 813 into a floating state.

The transistor 821 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 813. When the input terminal IN1 and the input terminal IN2 are at the H level, the transistor 821 has a function of decreasing the potential of the gate terminal of the transistor 813.

The transistor 851 functions as a switch for selecting whether to connect the second power supply and the gate terminal of the transistor 813 in accordance with the potential of the input terminal IN1. When the input terminal IN1 is at an L level, the transistor 851 has a function of supplying the power supply potential VDD to the gate terminal of the transistor 813.

The transistor 852 functions as a switch for selecting whether or not to connect the second power supply and the gate terminal of the transistor 813 depending on the potential of the input terminal IN2. When the input terminal IN2 is at an L level, the transistor 852 has a function of supplying the power supply potential VDD to the gate terminal of the transistor 813.

The transistor 861 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 813. When the input terminal IN1 and the input terminal IN2 are at the H level, the transistor 861 has a function of decreasing the potential of the gate terminal of the transistor 813.

The capacitor 815 has a function of changing the potential of the gate terminal of the transistor 813 in accordance with the potential of the output terminal OUT. When the input terminal IN1 or the input terminal IN2 is at an H level, the capacitor 815 has a function of reducing the potential of the gate terminal of the transistor 813.

As described above, the NAND circuits in FIGS. 81 to 87 can freely change the potential of the output terminal OUT by changing the power supply potential VSS when outputting the L level signal. That is, the NAND circuits in FIGS. 81 to 87 can operate not only as a NAND circuit but also as a level shift circuit.

Here, some configuration examples applicable to the NOR circuit 231 will be described.

FIG. 50 shows one form of the NOR circuit 231. The NOR circuit 500 in FIG. 50 includes a transistor 501, a transistor 502, and a transistor 503.

As shown in the NOR circuit 500 of FIG. 50, the first terminal of the transistor 501 is connected to the second power supply, and the second terminal is connected to the second terminal of the transistor 502, the second terminal of the transistor 503, and the output terminal OUT. The gate terminal is connected to the input terminal IN1. A first terminal of the transistor 502 is connected to the second power supply, and a gate terminal is connected to the input terminal IN2. A first terminal of the transistor 503 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VDD is supplied to the first power supply, and the power supply potential VSS is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VDD of the first power supply and the power supply potential VSS of the second power supply corresponds to the power supply voltage of the NOR circuit 500. The power supply potential VDD is higher than the power supply potential VSS.

A digital control signal is supplied to each of the input terminal IN1 and the input terminal IN2. The output terminal OUT outputs an output signal.

In addition, each of the transistors 501 to 503 is an N-channel type.

The operation of the NOR circuit 500 in FIG. 50 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is at the H level, and the case where the input terminal IN2 is at the H level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 501 is turned on. When the input terminal IN2 becomes H level, the transistor 502 is turned on.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 501, the second power supply through the transistor 502, and the first power supply through the transistor 503, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by operating points of the transistor 501, the transistor 502, and the transistor 503, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes H level, the transistor 501 is turned on. When the input terminal IN2 becomes L level, the transistor 502 is turned off.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 501 and the first power supply through the transistor 503, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by the operating point of the transistors 501 and 503, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 501 is turned off. When the input terminal IN2 becomes H level, the transistor 502 is turned on.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 502 and the first power supply through the transistor 503, and the potential of the output terminal OUT is lowered. The potential of the output terminal OUT at this time is determined by the operating point of the transistor 502 and the transistor 503, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 501 is turned off. When the input terminal IN2 becomes L level, the transistor 502 is turned off.

Accordingly, the output terminal OUT is electrically connected to the first power supply through the transistor 503, and the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT becomes a value obtained by subtracting the threshold potential Vth503 of the transistor 503 from the power supply potential VDD (VDD−Vth503), and the output terminal OUT becomes H level.

Note that the transistor 503 is not necessarily rectifying, and various elements can be used as long as they generate voltage when a current flows. For example, a resistance element 541 may be connected instead of the transistor 503 as in the NOR circuit 540 in FIG.

Here, functions of the transistors 501 to 503 are described below.

The transistor 501 functions as a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN1.

The transistor 502 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN2.

The transistor 503 functions as a diode.

FIG. 51 shows another form of the NOR circuit 231. A NOR circuit 510 in FIG. 51 includes a transistor 511, a transistor 512, a transistor 513, a transistor 514, and a capacitor 515 having two electrodes.

As shown in the NOR circuit 510 of FIG. 51, the first terminal of the transistor 511 is connected to the second power supply, the second terminal is the second terminal of the transistor 512, the second terminal of the transistor 513, and the second terminal of the capacitor 515. The electrode is connected to the output terminal OUT, and the gate terminal is connected to the input terminal IN1. A first terminal of the transistor 512 is connected to the second power supply, and a gate terminal is connected to the input terminal IN2. A first terminal of the transistor 513 is connected to the first power supply, and a gate terminal is connected to the second terminal of the transistor 514 and the first electrode of the capacitor 515. A first terminal of the transistor 514 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN1, the input terminal IN2, and the output terminal OUT can be the same as those in FIG.

In addition, the transistors 511 to 514 are each an N-channel type.

The operation of the NOR circuit 510 in FIG. 51 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is at the L level, the case where the input terminal IN2 is at the H level, and the case where the input terminal IN2 is at the L level.

First, the case where the input terminal IN is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 511 is turned on. When the input terminal IN2 becomes H level, the transistor 512 is turned on. The potential of the gate terminal of the transistor 513 is a value obtained by subtracting the threshold potential Vth 514 of the transistor 514 from the power supply potential VDD (VDD−Vth 514), and the transistor 513 is on. Further, the gate terminal of the transistor 513 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 511, the second power supply through the transistor 512, and the first power supply through the transistor 513, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by operating points of the transistors 511, 512, and 513, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes H level, the transistor 511 is turned on. When the input terminal IN2 becomes L level, the transistor 512 is turned off. The potential of the gate terminal of the transistor 513 is a value obtained by subtracting the threshold potential Vth 514 of the transistor 514 from the power supply potential VDD (VDD−Vth 514), and the transistor 513 is on. Further, the gate terminal of the transistor 513 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 511 and the first power supply through the transistor 513, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by operating points of the transistors 511, 512, and 513, and the output terminal OUT becomes L level.

First, the case where the input terminal IN is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 511 is turned off. When the input terminal IN2 becomes H level, the transistor 512 is turned on. The potential of the gate terminal of the transistor 513 is a value obtained by subtracting the threshold potential Vth 514 of the transistor 514 from the power supply potential VDD (VDD−Vth 514), and the transistor 513 is on. Further, the gate terminal of the transistor 513 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 512 and the first power supply through the transistor 513, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT is determined by operating points of the transistors 511, 512, and 513, and the output terminal OUT becomes L level.

First, the case where the input terminal IN is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 511 is turned off. When the input terminal IN2 becomes L level, the transistor 512 is turned off. The potential of the gate terminal of the transistor 513 is a value obtained by subtracting the threshold potential Vth 514 of the transistor 514 from the power supply potential VDD (VDD−Vth 514), and the transistor 513 is on. Further, the gate terminal of the transistor 513 is in a floating state.

Accordingly, the output terminal OUT is electrically connected to the first power supply through the transistor 513, and the potential of the output terminal OUT is increased. The potential of the gate terminal of the transistor 513 is increased to a value equal to or higher than the sum of the power supply potential VDD and the threshold potential Vth 513 of the transistor 513 due to capacitive coupling of the capacitor 515, and the transistor 513 is kept on. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VDD, and the output terminal OUT becomes H level.

Thus, in the NOR circuit 510 of FIG. 51, the potential of the H-level output terminal OUT can be raised to the power supply potential VDD of the first power supply by the bootstrap operation.

Note that the NOR circuit 510 in FIG. 51 is not limited to the circuit configuration in FIG. 51 as long as the bootstrap operation can be performed when the input terminal IN1 and the input terminal IN2 are at the L level. When the input terminal IN1 or the input terminal IN2 is at an H level, a potential may be supplied to the gate terminal of the transistor 513.

For example, a transistor 551 and a transistor 552 may be added as in the NOR circuit 550 in FIG. This is because the potential of the output terminal OUT can be set to VSS when the output terminal OUT is at the L level. That is, when one or both of the input terminal IN1 and the input terminal IN2 is at the H level, the transistor 551 and the transistor 552 are turned on, so that the gate terminal of the transistor 513 is at the L level. This is because the transistor 513 is turned off and the output terminal OUT is brought into conduction only with the second power supply through the transistor 511 or the transistor 512.

Note that each of the transistor 551 and the transistor 552 is an n-channel transistor.

Note that a variety of capacitors can be used as the capacitor 515 as long as it has capacitance. For example, as in the NOR circuit 520 in FIG. 52 and the NOR circuit 560 in FIG. 56, a transistor 521 and a transistor 561 may be connected instead of the capacitor 515, respectively.

Note that the capacitor 515 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 513 is sufficiently large. For example, as in the NOR circuit 530 in FIG. 53 and the NOR circuit 570 in FIG. 57, the capacitor 515 may not be connected.

Here, functions of the transistors 511 to 514, the transistor 521, the transistor 551, the transistor 552, the transistor 561, and the capacitor 515 are described below.

The transistor 511 functions as a switch that selects whether to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN1. When the input terminal IN1 is at the H level, the power supply potential VSS is supplied to the output terminal OUT.

The transistor 512 functions as a switch that selects whether or not to connect the second power supply and the output terminal OUT in accordance with the potential of the input terminal IN2. The power supply potential VSS is supplied to the output terminal OUT when the input terminal IN2 is at the H level.

The transistor 513 functions as a switch that selects whether to connect the first power supply and the output terminal OUT.

The transistor 514 functions as a diode. The transistor 514 has a function of bringing the gate terminal of the transistor 513 into a floating state.

The transistor 521 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 513. When the input terminal IN1 and the input terminal IN2 are at an L level, the transistor 521 has an ability to increase the potential of the gate terminal of the transistor 513.

The transistor 551 functions as a switch that selects whether to connect the second power supply and the gate terminal of the transistor 513 in accordance with the potential of the input terminal IN1. When the input terminal IN1 is at an H level, the transistor 551 has a function of supplying the power supply potential VSS to the gate terminal of the transistor 513.

The transistor 552 functions as a switch that selects whether to connect the second power supply and the gate terminal of the transistor 513 in accordance with the potential of the input terminal IN2. The transistor 552 has a function of supplying the power supply potential VSS to the gate terminal of the transistor 513 when the input terminal IN2 is at an H level.

The transistor 561 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 513. When the input terminal IN1 and the input terminal IN2 are at the L level, the transistor 561 has an ability to increase the potential of the gate terminal of the transistor 513.

The capacitor 515 has a function of changing the potential of the gate terminal of the transistor 513 in accordance with the potential of the output terminal OUT. When the input terminal IN1 and the input terminal IN2 are at the L level, the capacitor 515 has a function of increasing the potential of the gate terminal of the transistor 513.

50 to 57 can freely change the potential of the output terminal OUT by changing the power supply potential VDD when outputting an H level signal. That is, the NOR circuits in FIGS. 50 to 57 can operate not only as inverter circuits but also as level shift circuits.

In the NOR circuits of FIGS. 50 to 57, all the N-channel transistors have been described. However, the NOR circuits may be all P-channel transistors. Here, FIG. 72 to FIG. 79 show inverter circuits in the case where they are all constituted by P-channel transistors.

FIG. 72 shows another form of the NOR circuit 231. A NOR circuit 720 in FIG. 72 includes a transistor 721, a transistor 722, and a transistor 723.

As shown in the NOR circuit 720 of FIG. 72, the first terminal of the transistor 721 is connected to the second power supply, the second terminal is connected to the first terminal of the transistor 722, and the gate terminal is connected to the input terminal IN1. Yes. A second terminal of the transistor 722 is connected to the second terminal of the transistor 723 and the output terminal OUT, and a gate terminal is connected to the input terminal IN2. A first terminal of the transistor 723 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the power supply potential VSS is supplied to the first power supply, and the power supply potential VDD is supplied to the second power supply. A potential difference (VDD−VSS) between the power supply potential VSS of the first power supply and the power supply potential VDD of the second power supply corresponds to the power supply voltage of the NOR circuit 720. The power supply potential VDD is higher than the power supply potential VSS.

A control signal is supplied to each of the input terminal IN1 and the input terminal IN2. The output terminal OUT outputs an output signal.

In addition, each of the transistors 721 to 723 is a P-channel type.

The operation of the NOR circuit 720 of FIG. 72 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the H level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 is at an H level, the transistor 721 is turned off. When the input terminal IN2 is at an H level, the transistor 722 is turned off.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 723, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT becomes a value (VSS + | Vth723 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth723 of the transistor 723, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 is at an H level, the transistor 721 is turned off. When the input terminal IN2 becomes L level, the transistor 722 is turned on.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 723, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT becomes a value (VSS + | Vth723 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth723 of the transistor 723, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 721 is turned on. When the input terminal IN2 is at an H level, the transistor 722 is turned off.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 723, and the potential of the output terminal OUT is lowered. At this time, the potential of the output terminal OUT becomes a value (VSS + | Vth723 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth723 of the transistor 723, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 721 is turned on. When the input terminal IN2 becomes L level, the transistor 722 is turned on.

Thus, the output terminal OUT is electrically connected to the second power supply through the transistor 721 and the transistor 722 and the first power supply through the transistor 723, and the potential of the output terminal OUT is increased. The potential of the output terminal OUT at this time is determined by operating points of the transistor 721, the transistor 722, and the transistor 723, and the output terminal OUT becomes H level.

Note that the transistor 723 does not need to have a rectifying property, and various elements can be used as long as a voltage is generated when a current flows. For example, a resistance element 761 may be connected instead of the transistor 723 as in the NOR circuit 760 in FIG.

Here, functions of the transistors 721 to 723 are described below.

The transistor 721 functions as a switch that selects whether or not to connect the second power supply and the second terminal of the transistor 722 in accordance with the potential of the input terminal IN1.

The transistor 722 functions as a switch for selecting whether or not to connect the second terminal of the transistor 721 and the output terminal OUT in accordance with the potential of the input terminal IN2.

The transistor 723 has a function as a diode.

FIG. 73 shows another example of the NOR circuit 231. The NOR circuit 730 in FIG. 73 includes a transistor 731, a transistor 732, a transistor 733, a transistor 734, and a capacitor 735 having two electrodes.

As shown in the NOR circuit 730 in FIG. 73, the first terminal of the transistor 731 is connected to the second power supply, the second terminal is connected to the first terminal of the transistor 732, and the gate terminal is connected to the input terminal IN1. Yes. The second terminal of the transistor 732 is connected to the second terminal of the transistor 733, the second electrode of the capacitor 735, and the output terminal OUT, and the gate terminal is connected to the input terminal IN2. A first terminal of the transistor 733 is connected to the first power supply, a gate terminal is connected to the second terminal of the transistor 734, and the first electrode of the capacitor 735 is connected. A first terminal of the transistor 734 is connected to the first power supply, and a gate terminal is connected to the first power supply.

Note that the first power source, the second power source, the input terminal IN1, the input terminal IN2, and the output terminal OUT can be the same as those in FIG.

The transistors 731 to 734 are each a P-channel type.

The operation of the NOR circuit 730 in FIG. 73 will be described for each of the case where the input terminal IN1 is at the H level, the case where the input terminal IN2 is the H level, and the case where the input terminal IN2 is the H level.

First, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes H level, the transistor 731 is turned off. When the input terminal IN2 becomes H level, the transistor 732 is turned off. The potential of the gate terminal of the transistor 733 is a sum of the power supply potential VSS and the absolute value of the threshold potential Vth734 of the transistor 734 (VSS + | Vth734 |), and the transistor 733 is on. The gate terminal of the transistor 733 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 733, and the potential of the output terminal OUT is lowered. The potential of the gate terminal of the transistor 733 is decreased to a value (VSS− | Vth733 |) which is obtained by subtracting the absolute value of the threshold potential Vth733 of the transistor 733 from the power supply potential VSS due to capacitive coupling of the capacitor 735, and the transistor 733 is turned on Keep doing. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VSS, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the H level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes H level, the transistor 731 is turned off. When the input terminal IN2 becomes L level, the transistor 732 is turned on. The potential of the gate terminal of the transistor 733 is a value (VSS + | Vth734 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth734 of the transistor 734, and the transistor 733 is on. The gate terminal of the transistor 733 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 733, and the potential of the output terminal OUT is lowered. The potential of the gate terminal of the transistor 733 is decreased to a value (VSS− | Vth733 |) which is obtained by subtracting the absolute value of the threshold potential Vth733 of the transistor 733 from the power supply potential VSS due to capacitive coupling of the capacitor 735, and the transistor 733 is turned on Keep doing. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VSS, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the H level will be described. When the input terminal IN1 becomes L level, the transistor 731 is turned on. When the input terminal IN2 becomes H level, the transistor 732 is turned off. The potential of the gate terminal of the transistor 733 is a value (VSS + | Vth734 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth734 of the transistor 734, and the transistor 733 is on. The gate terminal of the transistor 733 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the first power supply through the transistor 733, and the potential of the output terminal OUT is lowered. The potential of the gate terminal of the transistor 733 is decreased to a value (VSS− | Vth733 |) that is obtained by subtracting the absolute value of the threshold potential Vth733 of the transistor 733 from the power supply potential VSS due to capacitive coupling of the capacitor 735, and the transistor 733 is turned on. Keep doing. A so-called bootstrap operation is performed. At this time, the potential of the output terminal OUT becomes VSS, and the output terminal OUT becomes L level.

Next, the case where the input terminal IN1 is at the L level and the input terminal IN2 is at the L level will be described. When the input terminal IN1 becomes L level, the transistor 731 is turned on. When the input terminal IN2 becomes L level, the transistor 732 is turned on. The potential of the gate terminal of the transistor 733 is a value (VSS + | Vth734 |) which is the sum of the power supply potential VSS and the absolute value of the threshold potential Vth734 of the transistor 734, and the transistor 733 is on. The gate terminal of the transistor 733 is in a floating state.

Therefore, the output terminal OUT is electrically connected to the second power supply through the transistor 731 and the transistor 732 and to the first power supply through the transistor 733, and the potential of the output terminal OUT is increased. At this time, the potential of the output terminal OUT is determined by operating points of the transistor 731, the transistor 732, and the transistor 733, and the output terminal OUT becomes H level.

In this manner, in the NOR circuit 730 in FIG. 73, the potential of the L-level output terminal OUT can be lowered to the power supply potential VSS of the first power supply by the bootstrap operation.

Note that the NOR circuit 730 in FIG. 73 is not limited to the circuit configuration in FIG. 73 as long as the bootstrap operation can be performed when the input terminal IN1 or the input terminal IN2 is at an H level. When the input terminal IN1 and the input terminal IN2 are at the L level, a potential may be supplied to the gate terminal of the transistor 733.

For example, a transistor 771 and a transistor 772 may be added as in a NOR circuit 770 in FIG. This is because the potential of the output terminal OUT can be set to VDD when the output terminal OUT is at the H level. That is, when the input terminal IN1 and the input terminal IN2 are at the L level, the transistor 771 or the transistor 772 is turned on, so that the gate terminal of the transistor 733 is at the H level. This is because the transistor 733 is turned off and the output terminal OUT is electrically connected only to the second power supply through the transistor 731 and the transistor 732.

Note that each of the transistors 771 and 772 is a P-channel type.

Note that a variety of capacitors can be used as the capacitor 735 as long as the element has capacitance. For example, as in the NOR circuit 740 in FIG. 74 and the NAND circuit 780 in FIG. 78, a transistor 741 and a transistor 781 may be connected instead of the capacitor 735, respectively.

Note that the capacitor 735 is not necessarily required as long as the capacitance value between the second terminal and the gate terminal of the transistor 733 is sufficiently large. For example, as in the NOR circuit 750 in FIG. 75 and the NOR circuit 790 in FIG. 79, the capacitor 735 may not be connected.

Here, functions of the transistors 731 to 734, the transistor 741, the transistor 771, the transistor 772, the transistor 781, and the capacitor 735 are described below.

The transistor 731 has a function as a switch for selecting whether or not to connect the second power supply and the first terminal of the transistor 732 depending on the potential of the input terminal IN1.

The transistor 732 has a function of a switch that selects the second terminal of the transistor 731 and the output terminal OUT in accordance with the potential of the input terminal IN2.

The transistor 733 functions as a switch for selecting whether to connect the first power supply and the output terminal OUT.

The transistor 734 functions as a diode. The transistor 734 has a function of bringing the gate terminal of the transistor 733 into a floating state.

The transistor 741 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 733. When one or both of the input terminal IN1 and the input terminal IN2 is at an H level, the transistor 741 has a function of decreasing the potential of the gate terminal of the transistor 733.

The transistor 771 functions as a switch that selects whether to connect the second power supply and the first terminal of the transistor 772 in accordance with the potential of the input terminal IN1.

The transistor 772 functions as a switch that selects whether to connect the first terminal of the transistor 771 and the gate terminal of the transistor 733 in accordance with the potential of the input terminal IN2.

The transistor 781 functions as a capacitor connected between the output terminal OUT and the gate terminal of the transistor 733. When one or both of the input terminal IN1 and the input terminal IN2 is at an H level, the transistor 781 has a function of reducing the potential of the gate terminal of the transistor 733.

The capacitor 735 has a function of changing the potential of the gate terminal of the transistor 733 in accordance with the potential of the output terminal OUT. When one or both of the input terminal IN1 and the input terminal IN2 is at an H level, the capacitor 735 has a function of reducing the potential of the gate terminal of the transistor 733.

As described above, when the NOR circuits in FIGS. 73 to 78 output an L level signal, the potential of the output terminal OUT can be freely changed by changing the power supply potential VSS. That is, the NOR circuits in FIGS. 73 to 78 can operate not only as a NAND circuit but also as a level shift circuit.

Further, by using the circuit configurations of FIGS. 28 to 87 as the inverter circuit 211, the NAND circuit 221, and the NOR circuit 231, a margin for operating the shift register circuit 200 is increased. This is because the above-described inverter circuit 211, NAND circuit 221, and NOR circuit 231 are characterized in that the gate terminal of one transistor is connected to the output terminal SRout. Therefore, since the load capacitance of the output terminal SRout is reduced, a margin for operating the shift register circuit 200 can be increased.

In addition, the inverter circuit, NAND circuit, and NOR circuit shown in FIGS. 28 to 87 are configured by transistors having the same polarity. Therefore, if the polarity of these transistors is the same as that of other transistors on the same substrate, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the power supply potential VDD or the power supply potential VSS is supplied to the first power supply and the second power supply illustrated in FIGS. 28 to 87; however, the present invention is not necessarily limited thereto.

For example, different potentials may be supplied to the first power source and the second power source in FIGS.

As another example, a control signal may be supplied to the first power supply and the second power supply in FIGS.

Although the control signals are supplied to the input terminals in FIGS. 28 to 87, the present invention is not necessarily limited to this.

For example, a power supply voltage may be supplied to the input terminals in FIGS.

Note that this embodiment mode can be freely combined with any description in other embodiment modes and embodiments in this specification. That is, the shift register circuit of the present invention supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.
(Embodiment 4)

In this embodiment, a structure different from that of the driver circuit described in Embodiment 3 is described.

A configuration example that can be applied to a source driver as a drive circuit will be described with reference to FIGS. The drive circuits shown in FIGS. 88 to 91 are not only applicable to source drivers, but can be applied to any circuit configuration.

FIG. 88 shows one mode of the source driver of the present invention. The source driver of the present invention includes a shift register circuit 880, a plurality of switches SW, and a video signal line 881.

As shown in the source driver of FIG. 88, the video signal line 881 is connected to the first terminal of the switch SW, and the second terminal of the switch SW is connected to the output terminal SDout. The control terminal of the switch SW is connected to the output terminal SRout of the shift register circuit 880.

Note that the shift register circuit 880 is similar to that described in Embodiment 2. The gate driver described in Embodiment 3 may be applied to the shift register circuit 880.

The output terminals SRout1 to SRout4 and the output terminal SRoutn of the shift register circuit 880 can be similar to those described in Embodiment 2.

In the gate driver of the present invention, the first stage output terminal SDout is the output terminal SDout1, the second stage output terminal SDout is the output terminal SDout2, the third stage output terminal SDout is the output terminal SDout3, and the nth stage. The output terminal SDout is referred to as an output terminal SDoutn.

In the source driver of FIG. 88, the power supply line and the control signal line are not shown for convenience.

In the case where the shift register circuit 880 includes N-channel transistors, the output signal of the shift register circuit 880 is the same as that in the timing chart of FIG. In the case where the shift register circuit 880 includes a P-channel transistor, the output signal of the shift register circuit 880 is the same as that in the timing chart of FIG.

A video signal is supplied to the video signal line 881. The video signal may be current or voltage, and may be analog or digital. Preferably, the video signal is an analog voltage. This is because many external circuits are for liquid crystal display devices. That is, if the video signal is an analog voltage, an existing inexpensive circuit can be used as the external circuit.

The operation of the source driver in FIG. 88 is described in the case where the output terminal SRout of the shift register circuit 880 is at the H level and the L level, respectively.

For convenience, the switch SW in FIG. 88 is turned on when the control terminal is at the H level and turned off when the control terminal is at the L level. Of course, the switch SW may be turned off when the control terminal is at the H level and turned on when the control terminal is at the L level.

First, the case where the output terminal SRout is at the H level will be described. When the output terminal SRout of the shift register circuit becomes H level, the switch SW is turned on. When the switch SW is turned on, the video signal line 881 is connected to the output terminal SRout of the source driver via the switch SW.

Therefore, since the output terminal SDout of the source driver has the same potential or the same current as the video signal line 881, the source driver outputs a video signal.

Next, the case where the output terminal SRout is at the L level will be described. When the output terminal SRout of the shift register circuit becomes L level, the switch SW is turned off. When the switch SW is turned off, the video signal line 881 is not connected to the output terminal SRout of the source driver.

Accordingly, since the output terminal SDout of the source driver is not affected by the potential of the video signal line 881, the source driver does not output a video signal.

As described in Embodiment 2, in the case where the shift register circuit 880 is formed using an N-channel transistor, the shift register circuit 880 sequentially becomes H level from the output terminal SRout1. That is, the switch SW illustrated in FIG. 88 is turned on sequentially from the switch SW1 (first column), and the output terminal SDout of the source driver becomes the same potential or the same current as the video signal sequentially from the output terminal SDout1 (first column). .

Note that the video signal is changed every time the shift register circuit 880 outputs an H level signal, whereby the source driver shown in FIG. 88 can output different video signals in order from the output terminal SDout1.

Note that one output terminal SRout of the shift register circuit 880 controls one switch, but the present invention is not necessarily limited thereto. Each output terminal SRout of the shift register circuit 880 may control a plurality of switches SW. In that case, a plurality of video signal lines may be connected to the first terminal of the switch SW.

For example, as in the source driver of FIG. 89, one output terminal SRout of the shift register circuit 880 may control three switches SW. Because the video signal line 891, the video signal line 892, and the video signal line 893 are connected to the first terminals of the three switches, respectively, the output terminals SDout of the three source drivers can simultaneously output video signals. It is. Therefore, since the operating frequency of the shift register circuit 880 can be slowed, power consumption of the shift register circuit 880 is suppressed.

For example, an electrical switch or a mechanical switch can be used as the switch SW. That is, it is only necessary to be able to control the current flow, and is not limited to a specific one. It may be a transistor, a diode, or a logic circuit combining them. Therefore, when a transistor is used as a switch, the transistor operates as a mere switch, and thus the polarity (conductivity type) of the transistor is not particularly limited. However, when it is desirable that the off-state current is small, it is desirable to use a transistor having a polarity with a small off-state current. As a transistor with low off-state current, there are a transistor provided with an LDD region and a transistor having a multi-gate structure. In addition, when the potential of the source terminal of the transistor that operates as a switch is close to the low potential side power supply (Vss, GND, 0 V, etc.), the N channel type is used. In the case of a state close to (such as Vdd), it is desirable to use a P-channel type. This is because the absolute value of the voltage between the gate and the source can be increased, so that it is easy to operate when functioning as a switch. Note that both N-channel and P-channel switches may be used as CMOS switches.

For example, as in the source driver in FIG. 90, the transistor 901 may be connected as the switch SW. The transistor 901 is controlled to be turned on / off by the shift register circuit 880. When the transistor 901 is turned on, the output terminal SDout of the source driver outputs a video signal.

Note that the transistor 901 is an n-channel transistor.

Note that the transistor 901 functions as a switch that selects whether to connect the video signal line 881 and the output terminal SDout of the source driver in accordance with the potential of the output terminal SRout of the shift register circuit 880. When the output terminal SRout of the shift register circuit 880 is at the H level, the transistor 901 supplies a video signal to the output terminal SDout of the source driver.

Note that the shift register circuit 880 at this time is preferably formed using an N-channel transistor. If the shift register circuit 880 is formed using an N-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

As another example, a transistor 911 may be connected as the switch SW as in the source driver in FIG. The transistor 911 is on / off controlled by a shift register circuit 880. When the transistor 911 is turned on, the output terminal SDout of the source driver circuit outputs a video signal.

Note that the transistor 911 is a P-channel type.

Note that the transistor 911 functions as a switch for selecting whether to connect the video signal line 881 and the output terminal SDout of the source driver in accordance with the potential of the output terminal SRout of the shift register circuit 880. When the output terminal SRout of the shift register circuit 880 is at an L level, the transistor 911 supplies a video signal to the output terminal SDout of the source driver.

Note that the shift register circuit 880 at this time is preferably formed using a P-channel transistor. If the shift register circuit 880 includes a P-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that this embodiment mode can be freely combined with any description in other embodiment modes and embodiments in this specification. That is, the shift register circuit of the present invention supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

(Embodiment 5)
In this embodiment, a layout diagram of the flip-flop circuit described in Embodiment 1 is described.

FIG. 122 shows a layout diagram of the flip-flop circuit 10 shown in FIG.

Note that the layout diagram of the flip-flop circuit illustrated in FIG. 122 is formed using amorphous silicon transistors.

122 includes a power supply line 12201, a control line 12202, a control line 12203, a control line 12204, a control line 12205, a power supply line 12206, an output terminal 12207, a transistor 11, a transistor 12, a transistor 13, a transistor 14, and a transistor 15. , Transistor 16, transistor 17, and transistor 18.

Note that reference numeral 12208 denotes a semiconductor layer, reference numeral 12209 denotes a gate electrode and a gate wiring layer, reference numeral 12210 denotes a second wiring layer, and reference numeral 12211 denotes a contact layer.

Connection relations of the flip-flop circuit illustrated in FIG. 122 are described. As shown in the flip-flop circuit 10, the gate terminal of the transistor 11 is connected to the input terminal IN 1, the first terminal is connected to the first power supply, the second terminal is the gate terminal of the transistor 12, and the second terminal of the transistor 14. To the gate terminal of the transistor 15, the second terminal of the transistor 17, and the second electrode of the capacitor 19. The first terminal of the transistor 15 is connected to the second power supply, and the second terminal is connected to the second terminal of the transistor 16 and the gate terminal of the transistor 18. The gate terminal and the first terminal of the transistor 16 are connected to the first power supply. A first terminal of the transistor 18 is connected to the input terminal IN 3, and a second terminal is connected to the gate terminal of the transistor 13 and the gate terminal of the transistor 14. The first terminal of the transistor 13 is connected to the second power supply, and the second terminal is connected to the first electrode of the capacitor 19, the second terminal of the transistor 12, and the output terminal OUT. A first terminal of the transistor 12 is connected to the input terminal IN2. The first terminal of the transistor 14 is connected to the second power source. The gate terminal of the transistor 17 is connected to the input terminal IN4, and the first terminal is connected to the second power source.

Note that the transistors 11 to 18 in FIG. 122 correspond to the transistors 11 to 18 in FIG. 1, respectively. A control line 12204, a control line 12202, a control line 12203, and a control line 12205 in FIG. 122 respectively correspond to the input terminal IN1 to the input terminal IN4 in FIG. The output terminal 12207 corresponds to the output terminal OUT in FIG.

Note that in the layout diagram of the flip-flop circuit in FIG. 122, the shape of the channel region of the transistor 15 is U-shaped. Note that as described above, the size of the transistor 15 needs to be large. Therefore, by making the channel region U-shaped as in the transistor 15 in FIG. 122, the transistor 15 can have a small area and a large size (or W / L ratio).

Note that the wiring widths of the control line 12202 and the control line 12203 are at least larger than those of the power supply line 12201. Note that in the flip-flop circuit in FIG. 122, more current or voltage is supplied to the flip-flop circuit than the power supply line 12201 through the control line 12202 and the control line 12203. Therefore, if the wiring widths of the control line 12202 and the control line 12203 are large, the influence of the voltage drop of the control line 12202 and the control line 12203 can be reduced.

Note that although the flip-flop circuit in FIG. 122 is configured using an amorphous silicon transistor, the present invention is not limited to this.

For example, like the flip-flop circuit in FIG. 123, the flip-flop circuit may be formed of a polysilicon transistor.

Here, a case where the flip-flop circuit is formed of a polysilicon transistor will be described.

122 includes a power supply line 12201, a control line 12202, a control line 12203, a control line 12204, a control line 12205, a power supply line 12206, an output terminal 12207, a transistor 11, a transistor 12, a transistor 13, a transistor 14, and a transistor 15. , Transistor 16, transistor 17, and transistor 18.

Note that reference numeral 12208 denotes a semiconductor layer, reference numeral 12209 denotes a gate electrode and a gate wiring layer, reference numeral 12210 denotes a second wiring layer, and reference numeral 12211 denotes a contact layer.

Connection relations of the flip-flop circuit illustrated in FIG. 122 are described. As shown in the flip-flop circuit 10, the gate terminal of the transistor 11 is connected to the input terminal IN 1, the first terminal is connected to the first power supply, the second terminal is the gate terminal of the transistor 12, and the second terminal of the transistor 14. To the gate terminal of the transistor 15, the second terminal of the transistor 17, and the second electrode of the capacitor 19. The first terminal of the transistor 15 is connected to the second power supply, and the second terminal is connected to the second terminal of the transistor 16 and the gate terminal of the transistor 18. The gate terminal and the first terminal of the transistor 16 are connected to the first power supply. A first terminal of the transistor 18 is connected to the input terminal IN 3, and a second terminal is connected to the gate terminal of the transistor 13 and the gate terminal of the transistor 14. The first terminal of the transistor 13 is connected to the second power supply, and the second terminal is connected to the first electrode of the capacitor 19, the second terminal of the transistor 12, and the output terminal OUT. A first terminal of the transistor 12 is connected to the input terminal IN2. The first terminal of the transistor 14 is connected to the second power source. The gate terminal of the transistor 17 is connected to the input terminal IN4, and the first terminal is connected to the second power source.

Note that the power supply line 12201, the control line 12202, the control line 12203, the control line 12204, the control line 12205, the power supply line 12206, the output terminal 12207, the transistor 11, the transistor 12, the transistor 13, the transistor 14, the transistor 15, the transistor 16, and the transistor 17 The transistor 18 can be the same as that in FIG.

Note that the semiconductor layer 12208, the gate wiring layer 12209 (gate electrode layer), the second wiring layer 12210, and the contact layer 12211 can be similar to those in FIG.

Note that the layout diagram of the flip-flop circuit in FIG. 123 is characterized in that the gate terminal of the transistor 13 and the gate terminal of the transistor 14 are connected to each other through the second wiring layer 12210. In this manner, the gate wiring layer 12209 can be shortened by connecting the gate terminal of the transistor 13 and the gate terminal of the transistor 14 through the second wiring layer 12210. It is known that when the gate wiring layer 12209 is long, electrostatic breakdown is likely to occur through the gate wiring layer 12209 in the manufacturing process of the semiconductor device. Therefore, by connecting the gate terminal of the transistor 13 and the gate terminal of the transistor 14 through the second wiring layer 12210, electrostatic breakdown through the gate wiring layer 12209 can be suppressed. In addition, by suppressing electrostatic breakdown, there are merits such as an improvement in yield, an improvement in productivity, and a longer life of a semiconductor device.

Note that the transistor 15 is characterized in that a channel region is divided into a plurality of regions. In this manner, by dividing the channel region into a plurality of portions, heat generation of the transistor 15 can be reduced, and deterioration in characteristics of the transistor 15 can be suppressed.

Note that this embodiment mode can be freely combined with any description in other embodiment modes and embodiments in this specification. That is, the shift register circuit of the present invention supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

In this embodiment, configurations of a display device, a gate driver, a source driver, and the like will be described. Note that the semiconductor device of the present invention can be applied to part of a gate driver. Further, it can be applied to a part of the source driver.

FIG. 92 shows one mode of a display device to which the present invention is applied. A display device 920 to which the present invention is applied includes a pixel region 921, a gate driver 922, a control signal line 923, and an FPC 926. The pixel region 921 includes a pixel, and the pixel includes a display element and a circuit for controlling the display element.

In FIG. 92, the FPC 926 is connected to the control signal line 923 and the source signal line 924. A gate driver is connected to the control signal line 923 and the gate signal line 925.

Note that the gate driver 922 can be the same as that described in the third embodiment.

A plurality of gate drivers 922 may be arranged.

Further, as already described, a display device which is a device including a display element or a light-emitting device which is a device including a light-emitting element can have various modes or have various elements. For example, a display medium whose contrast is changed by an electric or magnetic action, such as an EL element (an organic EL element, an inorganic EL element, or an EL element including an organic substance and an inorganic substance), an electron-emitting element, a liquid crystal element, and electronic ink, can be applied. it can. Note that an EL display is used as a display device using an EL element, and a liquid crystal display such as a field emission display (FED) or an SED type flat display (SED: Surface-Conduction Electron-Emitter Display) is used as a display device using an electron-emitting device. There is a liquid crystal display as a display device using an element, and an electronic paper as a display device using electronic ink.

The operation of the display device 920 will be briefly described.

The gate driver 922 sequentially outputs a selection signal to the pixel region 921 through the gate signal line 925. An external circuit sequentially outputs video signals to the pixel region 921 through the FPC 926 and the source signal line 924. The external circuit is not shown. In the pixel region 921, an image is displayed by controlling the state of light according to the video signal.

Note that a control signal is supplied to the control signal line 923 from an external circuit, and the gate driver 922 is controlled by the control signal. For example, the control signal includes a start pulse, a clock signal, and an inverted clock signal.

Note that the video signal may be a voltage value input or a current value input. For example, when a liquid crystal element is used as the display element, the video signal is preferably a voltage value input. This is because the liquid crystal element controls the slope of the liquid crystal element by an electric field, so that a video signal having a voltage value can be controlled more easily.

The video signal may be a digital value or an analog value. For example, when a liquid crystal element is used as the display element, the video signal is preferably an analog value. This is because the response speed of the liquid crystal element is slow, so that the liquid crystal element can be controlled by supplying an analog video signal only once in one frame period.

Note that although the FPC 926 is configured by one FPC 926, the present invention is not necessarily limited thereto. The FPC 926 may be divided into a plurality of pieces.

For example, the FPC 926 may be divided into three as in the display device 920 in FIG. This is because even when the display device is large or when the number of connections between the FPC 926 and the display device 920 is large, the existing FPC and the existing FPC crimping device can be used. That is, the manufacturing cost can be suppressed by using the existing FPC and the existing FPC crimping apparatus. Further, when the connection between the FPC 926 and the display device 920 fails, only the failed FPC 926 needs to be changed, so that the manufacturing cost can be suppressed.

Note that the video signal may be output to the pixel region 921 through any circuit and any element.

For example, as shown in FIG. 94, the video signal may be output to the pixel region 921 via the signal line control circuit 941. This is because if the signal line control circuit 941 has various functions, the configuration of the external circuit is simplified, and the cost of the entire display device is reduced. In addition, the number of connections between the FPC 926 and the display device 920 is significantly reduced.

Note that the video signal and the control signal are supplied to the signal line control circuit 941 through the control signal line 942.

As described above, various structures can be applied to the display device of the present invention.

In the present embodiment, various configurations of display devices are shown, but the configuration of the display device of the present invention is not limited to these display devices.

Note that this embodiment can be freely combined with any description in the other embodiments and examples in this specification. In other words, the gate driver and the source driver including the shift register circuit of the present invention supply the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

Next, a specific configuration of the signal line control circuit 941 described in the first embodiment will be described.

As the signal line control circuit 941, the source driver described in Embodiment 4 can be used.

FIG. 95 shows one mode of a signal line control circuit 941 different from the source driver described in Embodiment 4. The signal line control circuit 950 in FIG. 95 includes a plurality of switches SW.

As shown in FIG. 95, the video signal line 954 is connected to the first terminal of the switch SW1, the first terminal of the switch SW2, and the first terminal of the switch SW3. A second terminal of the switch SW1 is connected to the source signal line 955, a second terminal of the switch SW2 is connected to the source signal line 956, and a second terminal of the switch SW3 is connected to the source signal line 957. The control terminal of the switch SW1 is connected to the control signal line 951, the control terminal of the switch SW2 is connected to the control signal line 952, and the control terminal of the switch SW3 is connected to the control signal line 953. The video signal line 954, the control signal line 951, the control signal line 952, and the control signal line 953 are connected to an external circuit through the FPC.

Note that a control signal A is supplied to the control signal line 951, a control signal B is supplied to the control signal line 952, and a control signal C is supplied to the control signal line 953. A video signal is supplied to the video signal line 954.

Further, as described above, for example, an electrical switch or a mechanical switch can be used for the switches SW1 to SW3. That is, it is only necessary to be able to control the current flow, and is not limited to a specific one. It may be a transistor, a diode, or a logic circuit combining them. Therefore, when a transistor is used as a switch, the transistor operates as a mere switch, and thus the polarity (conductivity type) of the transistor is not particularly limited. However, when it is desirable that the off-state current is small, it is desirable to use a transistor having a polarity with a small off-state current. As a transistor with low off-state current, there are a transistor provided with an LDD region and a transistor having a multi-gate structure. In addition, when the potential of the source terminal of the transistor that operates as a switch is close to the low potential side power supply (Vss, GND, 0 V, etc.), the N channel type is used. In the case of a state close to (such as Vdd), it is desirable to use a P-channel type. This is because the absolute value of the voltage between the gate and the source can be increased, so that it is easy to operate when functioning as a switch. Note that both N-channel and P-channel switches may be used as CMOS switches.

The operation of the signal line control circuit 950 in FIG. 95 will be described.

The control signal A, the control signal B, and the control signal C are signals that turn on the switch SW1, the switch SW2, and the switch SW3 in order. The value of the video signal changes depending on whether the switch SW1, the switch SW2, and the switch SW3 are on or off.

First, the switch SW1 is turned on by the control signal A. At that time, the switch SW2 is turned off by the control signal B, and the switch SW3 is turned off by the control signal C. Therefore, the video signal is supplied to the source signal line 955 via the video signal line 954 and the switch SW1. At this time, since the switch SW2 and the switch SW3 are off, the video signal is not supplied to the source signal line 956 and the source signal line 957.

Next, the switch SW2 is turned on by the control signal B. At that time, the switch SW1 is turned off by the control signal A, and the switch SW3 is turned off by the control signal C. Therefore, the video signal is supplied to the source signal line 956 via the video signal line 954 and the switch SW2. At this time, since the switch SW1 and the switch SW3 are turned off, the video signal is not supplied to the source signal line 955 and the source signal line 957.

Next, the switch SW3 is turned on by the control signal C. At that time, the switch SW1 is turned off by the control signal A, and the switch SW3 is turned off by the control signal B. Therefore, the video signal is supplied to the source signal line 957 via the video signal line 954 and the switch SW3. At this time, since the switch SW1 and the switch SW2 are off, the video signal is not supplied to the source signal line 955 and the source signal line 956.

Through the above operation, a video signal is supplied to the three source signal lines 955, 956, and 957 through one video signal line 954. In other words, the number of video signal lines 954 is 1/3 of the number of source signal lines, so that the number of connections between the FPC and the display device is significantly reduced. Therefore, the probability of failure in connection between the FPC and the display device is greatly reduced.

Note that the signal line control circuit 950 of FIG. 95 includes three switches SW, but the present invention is not limited to this. Any number of switches SW may be used. At that time, it is necessary to change the number of control signals corresponding to the number of switches SW. For example, when there are four switches SW, the number of control signals is four.

Note that the signal line control circuit 950 in FIG. 95 may have a period in which none of the switches SW1 to SW3 is turned on. This is because image defects such as crosstalk are suppressed. That is, even when a new video signal is supplied to the source signal line, the potential of the source signal line does not change immediately. Therefore, the influence of the potential before the source signal line may remain in the source signal line, and image defects such as crosstalk occur. This period is a preparation period for writing the next row.

Note that the control signal A, the control signal B, and the control signal C may be supplied by the shift register circuit of the second embodiment. At this time, the shift register circuit has three or more flip-flop circuits. Preferably, the shift register circuit includes three or more flip-flop circuits and five or less flip-flop circuits.

Note that when the signal line control circuit 950 is formed over the same substrate in the display device 920, the number of connections between the FPC and the display device 920 can be further reduced.

As described above, various signal control circuits can be used in the display device of the present invention.

Note that although various signal control circuits are shown in this embodiment, a signal control circuit that can be used in the display device of the present invention is not limited to these signal control circuits.

Note that this embodiment can be freely combined with any description in the other embodiments and examples in this specification. That is, the signal control circuit including the shift register circuit of the present invention supplies the power supply potential to the output terminal when the transistor is turned on every predetermined time in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

Next, a specific configuration of the pixel described in the first embodiment will be described.

FIG. 96 shows one mode of a pixel. A pixel 960 in FIG. 96 includes a transistor 961, a liquid crystal element 962 having two electrodes, and a capacitor 963 having two electrodes.

As shown in the pixel 960 in FIG. 96, the first terminal of the transistor 961 is connected to the source signal line 924, the second terminal is connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963, and the gate A terminal is connected to the gate signal line 925. The second electrode of the liquid crystal element 962 is a counter electrode 964. A second electrode of the capacitor 963 is connected to the common line 965.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.

Note that a common potential is supplied to the common line 965. Further, a substrate potential is supplied to the counter electrode 964. The common potential and the substrate potential are constant potentials.

The transistor 961 is an N-channel type.

The operation of the pixel 960 in FIG. 96 will be described for a case where a selection signal is supplied to the gate signal line 925 (H level) and a case where a selection signal is not supplied (L level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes H level and the transistor 961 is turned on. The source signal line 924 is electrically connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963. The potential of the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963 is the potential of the source signal line 924. And the same potential.

Here, the potential of the source signal line 924 is a potential corresponding to the video signal.

The light transmittance of the liquid crystal element 962 is determined by the potential corresponding to the video signal. The capacitor 963 holds a potential corresponding to the video signal.

Next, the second period will be described. The gate signal line 925 becomes L level, and the transistor 961 is turned off. The source signal line 924 is not electrically connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963. Accordingly, the potential of the first electrode of the liquid crystal element 962 and the potential of the first electrode of the capacitor 963 is maintained at a potential corresponding to the previously input video signal, and thus the light transmittance of the liquid crystal element 962 is also maintained. .

Here, functions of the transistor 961 and the capacitor 963 are described below.

The transistor 961 functions as a switch for selecting whether or not to connect the source signal line 924 to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963 in accordance with the potential of the gate signal line 925. Have In the first period, the transistor 961 has a function of supplying a video signal to the pixel 960.

The capacitor 963 has a function of holding a video signal. In the first period, a video signal is supplied to the capacitor 963, and the capacitor 963 has a function of holding a video signal. In the second period, the capacitor 963 has a function of holding a video signal until the next first period.

Thus, the pixel 960 can be driven actively. In addition, when another transistor on the same substrate as the pixel 960 is an n-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the second electrode of the capacitor 963 may be connected anywhere as long as it has a constant potential during the operation period of the pixel 960. For example, the second electrode of the capacitor 963 may be connected to the gate signal line 925 in the previous row. This is because the common line 965 is not necessary and the aperture ratio of the pixel 960 is increased.

Note that the counter electrode 964 is supplied with a constant potential; however, the present invention is not limited to this. For example, when the pixel 960 is driven in an inverted manner, the potential of the counter electrode 964 may change corresponding to the inverted drive. At that time, when the video signal has a positive potential, the potential of the counter electrode 964 becomes a negative potential. When the video signal has a negative potential, the potential of the counter electrode 964 becomes a positive potential.

The pixel in FIG. 96 has been described with respect to the case where the pixel is configured with an N-channel transistor, but may be configured with a P-channel transistor. Here, FIG. 120 shows a pixel in the case of being formed of a P-channel transistor.

FIG. 120 shows one mode of a pixel. A pixel 1200 in FIG. 120 includes a transistor 1201, a liquid crystal element 962 having two electrodes, and a capacitor 963 having two electrodes.

As shown in the pixel 1200 in FIG. 120, the first terminal of the transistor 1201 is connected to the source signal line 924, the second terminal is connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963, and the gate A terminal is connected to the gate signal line 925. The second electrode of the liquid crystal element 962 is a counter electrode 964. A second electrode of the capacitor 963 is connected to the common line 965.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.

Note that a common potential is supplied to the common line 965. Further, a substrate potential is supplied to the counter electrode 964. The common potential and the substrate potential are constant potentials.

Note that the liquid crystal element 962, the capacitor 963, the counter electrode 964, and the common line 965 can be similar to those in FIG.

The transistor 1201 is a P-channel type.

The operation of the pixel 1200 in FIG. 120 is described with respect to a case where the selection signal is supplied to the gate signal line 925 (L level) and a case where the selection signal is not supplied (H level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes L level, and the transistor 1201 is turned on. The source signal line 924 is electrically connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963. The potential of the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963 is the potential of the source signal line 924. And the same potential.

Here, the potential of the source signal line 924 is a potential corresponding to the video signal.

The light transmittance of the liquid crystal element 962 is determined by the potential corresponding to the video signal. The capacitor 963 holds a potential corresponding to the video signal.

Next, the second period will be described. The gate signal line 925 becomes H level and the transistor 1201 is turned off. The source signal line 924 is not electrically connected to the first electrode of the liquid crystal element 962 and the first electrode of the capacitor 963. Accordingly, the potential of the first electrode of the liquid crystal element 962 and the potential of the first electrode of the capacitor 963 is maintained at a potential corresponding to the previously input video signal, and thus the light transmittance of the liquid crystal element 962 is also maintained. .

Here, functions of the transistor 1201 and the capacitor 963 are described below.

The transistor 1201 functions as a switch for selecting whether to connect the source signal line 924 to the first terminal of the liquid crystal element 962 and the first electrode of the capacitor 963 in accordance with the potential of the gate signal line 925. Have In the first period, the transistor 1201 has a function of supplying a video signal to the pixel 1200.

Thus, the pixel 1200 can be driven actively. If another transistor on the same substrate as the pixel 1200 is a P-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the second electrode of the capacitor 963 may be connected anywhere as long as it has a constant potential during the operation period of the pixel 1200. For example, the second electrode of the capacitor 963 may be connected to the gate signal line 925 in the previous column. This is because the common line 965 is not necessary and the aperture ratio of the pixel 1200 is increased.

Note that the counter electrode 964 is supplied with a constant potential; however, the present invention is not limited to this. For example, when the pixel 1200 is driven in an inverted manner, the potential of the counter electrode 964 may change corresponding to the inverted drive. At that time, when the video signal has a positive potential, the potential of the counter electrode 964 becomes a negative potential. When the video signal has a negative potential, the potential of the counter electrode 964 becomes a positive potential.

FIG. 97 shows another embodiment of a pixel. A pixel 970 in FIG. 97 includes a transistor 971, a transistor 972, a display element 973 having two electrodes, and a capacitor 974 having two electrodes.

As shown in the pixel 970 in FIG. 97, the first terminal of the transistor 971 is connected to the source signal line 924, the second terminal is connected to the gate terminal of the transistor 972, and the first electrode of the capacitor 974, and the gate terminal is A gate signal line 925 is connected. A second electrode of the capacitor 974 is connected to the power supply line 976. A first terminal of the transistor 972 is connected to the power supply line 976, and a second terminal is connected to the first electrode of the display element 973. A second electrode of the display element 973 is a common electrode 975.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.
it can.

Note that an anode potential is supplied to the power supply line 976. Further, a cathode potential is supplied to the common electrode 975. The anode potential is higher than the cathode potential.

In addition, the transistor 971 and the transistor 972 are each an N-channel type.

The operation of the pixel 970 in FIG. 97 is described with respect to a case where a selection signal is supplied to the gate signal line 925 (H level) and a case where the selection signal is not supplied (L level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes H level and the transistor 971 is turned on. The source signal line 924 is electrically connected to the gate terminal of the transistor 972 and the first electrode of the capacitor 974. The potential of the gate terminal of the transistor 972 and the first electrode of the capacitor 974 is the same as the potential of the source signal line 924. It becomes the same potential as the potential of 924.

Here, the potential of the source signal line 924 is a potential corresponding to the video signal.

The current value of the transistor 972 is determined by the potential difference (Vgs) between the potential corresponding to the video signal and the second terminal of the transistor 972, and the same current as the transistor 972 flows to the display element 973. In that case, the operating point of the transistor 972 and the display element 973 needs to operate in a saturation region. Thus, the current value of the display element 973 can be freely determined by the video signal.

Note that in the case where the operating point of the transistor 972 and the display element 973 operates in a linear region, the first electrode of the display element 973 is electrically connected to the power supply line 976 through the transistor 972 and a voltage substantially equal to the potential of the power supply line 976 is displayed. Applied to the first electrode of the element 973. In addition, when the operating points of the transistor 972 and the display element 973 operate in a linear region, it is advantageous because the current value of the transistor 972 is not affected by variations in characteristics or deterioration of the transistor 972.

Next, a case where a selection signal is not supplied to the gate signal line 925 will be described. The gate signal line 925 becomes L level, and the transistor 971 is turned off. The source signal line 924 does not conduct with the second terminal of the transistor 972. Therefore, the potential of the second terminal of the transistor 972 is maintained at a potential corresponding to the previously input video signal, and thus Vgs of the transistor 972 is maintained as it is. Therefore, the current value of the display element 973 is also maintained as it is.

Here, functions of the transistor 971, the transistor 972, and the capacitor 974 are described below.

The transistor 971 functions as a switch that selects whether to connect the source signal line 924, the gate terminal of the transistor 972, and the first electrode of the capacitor 974 depending on the potential of the gate signal line 925. . In the first period, the transistor 971 has a function of supplying a video signal to the pixel 970.

The transistor 972 functions as a driving transistor that supplies current or voltage to the display element 973 in accordance with the potentials of the gate terminal of the transistor 972 and the first electrode of the capacitor 974. In the case where the operating point of the transistor 972 and the display element 973 operates in a saturation region, the transistor 972 functions as a current source that supplies current to the display element 973. Further, when the operating point of the transistor 972 and the display element 973 operates in a linear region, the transistor 972 functions as a switch that selects whether or not to connect the power supply line 976 and the first electrode of the display element 973. Have

The capacitor 974 has a function of holding a video signal. In the first period, a video signal is supplied to the capacitor 974, and the capacitor 974 has a function of holding a video signal. In the second period, the capacitor 974 has a function of holding a video signal until the next first period.

Thus, the pixel 970 can be driven actively. In addition, when another transistor on the same substrate as the pixel 970 is an n-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the second electrode of the capacitor 974 may be connected anywhere as long as it has a constant potential during the operation period of the pixel 970. For example, the second electrode of the capacitor 974 may be connected to the gate signal line 925 in the previous column.

As another example, the pixel 980 in FIG. 98 may be connected to the second terminal of the transistor 972. This is because the potential of the gate terminal of the transistor 972 changes in accordance with the change in the potential of the second terminal of the transistor 972, and thus a more accurate current is supplied to the display element. That is, when the potential of the second terminal of the transistor 972 varies, the potential of the gate terminal of the transistor varies simultaneously due to capacitive coupling of the capacitor 974. A so-called bootstrap operation is performed.

In the pixel in FIG. 97, the case where all of the pixels are configured by N-channel transistors has been described. However, all of the pixels may be configured by P-channel transistors. Here, FIG. 121 shows a pixel in the case where all of the transistors are P-channel transistors.

FIG. 121 illustrates another embodiment of a pixel. A pixel 1210 in FIG. 121 includes a transistor 1211, a transistor 1212, a display element 973 having two electrodes, and a capacitor 974 having two electrodes.

As shown in the pixel 1210 in FIG. 121, the first terminal of the transistor 1211 is connected to the source signal line 924, the second terminal is connected to the gate terminal of the transistor 1212 and the first electrode of the capacitor 974, and the gate terminal is A gate signal line 925 is connected. A second electrode of the capacitor 974 is connected to the power supply line 976. A first terminal of the transistor 1212 is connected to the power supply line 976, and a second terminal is connected to the first electrode of the display element 973. A second electrode of the display element 973 is a common electrode 975.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.
it can.

Note that an anode potential is supplied to the power supply line 976. Further, a cathode potential is supplied to the common electrode 975. The anode potential is higher than the cathode potential.

Note that the display element 973, the capacitor 974, the common electrode 975, and the power supply line 976 can be similar to those in FIG.

In addition, the transistor 1211 and the transistor 1212 are each a P-channel type.

The operation of the pixel 1210 in FIG. 121 is described with respect to a case where a selection signal is supplied to the gate signal line 925 (L level) and a case where the selection signal is not supplied (H level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes L level and the transistor 1211 is turned on. The source signal line 924 is electrically connected to the gate terminal of the transistor 1212 and the first electrode of the capacitor 974. The potential of the gate terminal of the transistor 1212 and the first electrode of the capacitor 974 is the same as the potential of the source signal line 924. It becomes the same potential as the potential of 924.

Here, the potential of the source signal line 924 is a potential corresponding to the video signal.

The current value of the transistor 1212 is determined by the potential difference (Vgs) between the potential corresponding to the video signal and the potential of the power supply line 976, and the same current flows through the display element 973. In that case, the operating point of the transistor 1212 and the display element 973 needs to operate in a saturation region. Thus, the current value of the display element 973 can be freely determined by the video signal.

Note that when the operating point of the transistor 1212 and the display element 973 operates in a linear region, the first electrode of the display element 973 is electrically connected to the power supply line 976 through the transistor 1212 and the potential of the first electrode of the display element 973 is applied. Is done. Further, it is advantageous that the operating point of the transistor 1212 and the display element 973 operate in a linear region because the current value of the transistor 1212 is not affected by variation in characteristics of the transistor 1212 or deterioration.

Next, a case where a selection signal is not supplied to the gate signal line 925 will be described. The gate signal line 925 becomes H level and the transistor 1211 is turned off. The source signal line 924 does not conduct with the second terminal of the transistor 1212. Accordingly, the potential of the second terminal of the transistor 1212 is maintained at a potential corresponding to the previously input video signal, and thus Vgs of the transistor 1212 is maintained as it is. Therefore, the current value of the display element 973 is also maintained as it is.

Here, the functions of the transistor 1211 and the transistor 1212 are described below.

The transistor 1211 functions as a switch for selecting whether or not to connect the source signal line 924, the gate terminal of the transistor 1212, and the first terminal of the capacitor 974 depending on the potential of the gate signal line 925. . In the first period, the transistor 1211 has a function of supplying a video signal to the pixel 1210.

The transistor 1212 functions as a driving transistor that supplies current or voltage to the display element 973 in accordance with the potentials of the gate terminal of the transistor 1212 and the second electrode of the capacitor 974. In the case where the operating point of the transistor 1212 and the display element 973 operates in a saturation region, the transistor 1212 functions as a current source that supplies current to the display element 973. When the operating point of the transistor 1212 and the display element 973 operates in a linear region, the transistor 1212 functions as a switch that selects whether or not to connect the power supply line 976 and the first electrode of the display element 973. Have

Thus, the pixel 970 can be driven actively. In addition, when another transistor on the same substrate as the pixel 970 is an n-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the second electrode of the capacitor 974 may be connected anywhere as long as it has a constant potential during the operation period of the pixel 1210. For example, the second electrode of the capacitor 974 may be connected to the gate signal line 925 in the previous column.

FIG. 99 shows another embodiment of a pixel. A pixel 990 in FIG. 99 includes a transistor 991, a transistor 992, a transistor 993, a display element 973 having two electrodes, and a capacitor 994 having two electrodes.

As shown in the pixel 990 in FIG. 99, the first terminal of the transistor 991 is connected to the source signal line 924, the second terminal is the second terminal of the transistor 992, the first electrode of the capacitor 994, and the first terminal of the display element 973. Connected to one electrode. A first terminal of the transistor 992 is connected to the power supply line 995, and a gate terminal is connected to the second terminal of the transistor 993 and the second electrode of the capacitor 994. A first terminal of the transistor 993 is connected to the gate signal line 925, and a gate terminal is connected to the power supply line 995. A second electrode of the display element 973 is a common electrode 975.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.

The video signal is an analog current.

Note that a control potential is supplied to the power supply line 995. A cathode potential is supplied to the common electrode. In addition, the control potential changes depending on the operation of the pixel 990.

Note that the display element 973 and the common electrode 975 can be similar to those in FIG.

In addition, the transistors 991 to 993 are each an N-channel type.

The operation of the pixel 990 in FIG. 99 will be described for each of the case where the selection signal is supplied to the gate signal line 925 (H level) and the case where the selection signal is not supplied (L level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes H level, and the transistor 991 and the transistor 993 are turned on. The first terminal and the gate terminal of the transistor 992 are electrically connected through the transistor 993, and the transistor 992 is diode-connected. In addition, the source signal line 924 is electrically connected to the second terminal of the transistor 992, the first electrode of the capacitor 994, and the first electrode of the display element 973.

At this time, the power supply line 995 is set to a potential such that the potential of the first electrode of the display element 973 is lower than the potential of the common electrode 975.

The video signal supplies an analog current to the pixel 990 so that current flows from the power supply line 995 to the source signal line 924 through the transistor 992 and the transistor 991. Then, the same current as the video signal flows through the transistor 992. Since the transistor 992 is diode-connected, the capacitor 994 holds the voltage (Vgs) between the first terminal and the gate terminal of the transistor 992 at that time.

Note that since the first electrode of the display element 973 is lower than the potential of the common electrode, the display element 973 does not emit light.

Next, the second period will be described. The gate signal line 925 becomes L level, and the transistor 991 and the transistor 993 are turned off. The first terminal and the gate terminal of the transistor 992 are not conducted through the transistor 993, and the transistor 992 is not diode-connected. Further, the source signal line 924, the second terminal of the transistor 992, the first electrode of the capacitor 994, and the first electrode of the display element 973 are not brought into conduction.

At this time, the power supply line 995 is set to a potential such that the potential of the first electrode of the display element 973 is higher than the potential of the common electrode 975.

The capacitor 994 holds a voltage that allows the transistor 992 to pass a current similar to that of a video signal. When the potential of the power supply line 995 is increased, the potential of the first electrode of the capacitor 994 is also increased. Here, the potential of the gate terminal of the transistor 992 is increased by the capacitive coupling of the capacitor 994, and Vgs of the transistor 992 is maintained as it is. Therefore, the same current as the video signal flows through the display element 973.

Here, functions of the transistors 991 to 993 and the capacitor 994 are described below.

Whether or not the transistor 991 connects the source signal line 924 to the second terminal of the transistor 992, the first electrode of the capacitor 994, and the first electrode of the display element 973 depending on the potential of the gate signal line 925. It has a function as a switch for selecting. In the first period, the transistor 991 has a function of supplying a video signal to the pixel 990.

The transistor 992 functions as a current source that supplies current to the display element 973 in accordance with the potentials of the gate terminal of the transistor 992, the second terminal of the transistor 993, and the second electrode of the capacitor 994.

The transistor 993 functions as a switch for selecting whether or not to connect the first terminal of the transistor 992 and the gate terminal of the transistor 992. In the first period, the transistor 993 has a function of making the transistor 992 into a diode connection.

The capacitor 994 has a function of changing the potential of the gate terminal of the transistor 992 in accordance with the first electrode of the display element 973. In the second period, the capacitor 994 has a function of increasing the potential of the gate terminal of the transistor 992 by increasing the potential of the first electrode of the display element 973.

Thus, the pixel 990 can be driven actively. In addition, when another transistor on the same substrate as the pixel 990 is an n-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

FIG. 118 illustrates another embodiment of a pixel. A pixel 1180 in FIG. 118 includes a transistor 1181, a transistor 1182, a transistor 1183, a transistor 1184, a display element 973 having two electrodes, and a capacitor 974 having two electrodes.

118, the first terminal of the transistor 1181 is connected to the source signal line 924, the second terminal is the second terminal of the transistor 1182, the gate terminal of the transistor 1183, the gate terminal of the transistor 1184, and the capacitor. The gate terminal of the element 974 is connected to the gate signal line 925. A first terminal of the transistor 1182 is connected to a first terminal of the transistor 1183, and a gate terminal is connected to the gate signal line 925. A second terminal of the transistor 1183 is connected to a second terminal of the transistor 1184 and a first electrode of the display element 973. A first terminal of the transistor 1184 is connected to the power supply line 976. A second electrode of the capacitor 974 is connected to the power supply line 976. A second electrode of the display element 973 is a common electrode 975.

Note that a video signal is supplied to the source signal line 924. A selection signal is supplied to the gate signal line 925. The source signal line 924 and the gate signal line 925 can be the same as those in the first embodiment.

The video signal is an analog current.

Note that an anode potential is supplied to the power supply line 976. Further, a cathode potential is supplied to the common electrode 975. The anode potential is higher than the cathode potential.

Note that the display element 973, the common electrode 975, and the power supply line 976 can be similar to those in FIG.

In addition, each of the transistors 1181 to 1184 is an N-channel type.

The operation of the pixel 1180 in FIG. 118 is described with respect to a case where a selection signal is supplied to the gate signal line 925 (H level) and a case where the selection signal is not supplied (L level). In addition, a period in which the selection signal is supplied to the gate signal line 925 is a first period, and a period in which the selection signal is not supplied is a second period.

First, the first period will be described. The gate signal line 925 becomes H level, and the transistor 1181 and the transistor 1182 are turned on. The first terminal and the gate terminal of the transistor 1183 are electrically connected through the transistor 1182, and the transistor 1183 is diode-connected. In addition, the source signal line 924 is electrically connected to the first terminal of the transistor 1182, the gate terminal of the transistor 1183, the gate terminal of the transistor 1184, and the second electrode of the capacitor 974.

The video signal supplies an analog current to the pixel 1180 so that current flows from the source signal line 924 to the common electrode 975 through the transistor 1181, the transistor 1182, the transistor 1183, and the display element 973. Then, the same current as the video signal flows through the transistor 1183. Since the gate terminal of the transistor 1183, the gate terminal of the transistor 1184, and the second electrode of the capacitor 974 are connected to each other, the second electrode of the capacitor 974 holds the potential of the gate terminal of the transistor 1183 at that time. The

Next, the second period will be described. The gate signal line 925 becomes L level, and the transistor 1181 and the transistor 1182 are turned off. The first terminal and the gate terminal of the transistor 1183 are not conducted through the transistor 1182. Further, the source signal line 924 and the first terminal of the transistor 1182, the gate terminal of the transistor 1183, the gate terminal of the transistor 1184, and the second electrode of the capacitor 974 are not conductive.

The capacitor 974 holds a potential corresponding to the video signal. That is, the potential of the gate terminal of the transistor 1183 is similar to the potential acquired in the first period. Therefore, since the potential of the gate terminal of the transistor 1184 is similar to the potential of the second electrode of the capacitor 974, the transistor 1184 can supply a current corresponding to the video signal to the display element 973.

Here, functions of the transistors 1181 to 1184 are described below.

The transistor 1181 connects the source signal line 924 to the first terminal of the transistor 1182, the gate terminal of the transistor 1183, the gate terminal of the transistor 1184, and the second electrode of the capacitor 974 depending on the potential of the gate signal line 925. It has a function as a switch for selecting whether or not to perform. In the first period, the transistor 1181 has a function of supplying a video signal to the pixel 1180.

The transistor 1182 has a function as a switch for selecting whether or not to connect the first terminal of the transistor 1183 and the gate terminal of the transistor 1183 depending on the potential of the gate signal line 925. In the first period, the transistor 1182 has a function of diode-connecting the transistor 1183.

The transistor 1183 has a function of determining the potential of the first electrode of the display element 973 and the potential of the gate terminal of the transistor 1184 in accordance with the video signal.

The transistor 1184 functions as a current source that supplies current to the display element 973 in accordance with the potential of the second electrode of the capacitor 974.

In this manner, the pixel 1180 can be driven actively. In addition, when another transistor on the same substrate as the pixel 1180 is an n-channel transistor, the manufacturing process can be simplified. Therefore, the manufacturing cost can be reduced and the yield can be improved.

Note that the first electrode of the capacitor 974 may be connected anywhere as long as it has a constant potential during the operation period of the pixel 1180. For example, the first electrode of the capacitor 974 may be connected to the gate signal line 925 in the previous column.

As another example, the first electrode of the capacitor 974 may be connected to the second terminal of the transistor 1184 as in the pixel 1190 in FIG. This is because the potential of the gate terminal of the transistor 1184 changes in accordance with the change in the potential of the second terminal of the transistor 1184, and thus a more accurate current is supplied to the display element. In other words, when the transistor sizes of the transistor 1183 and the transistor 1184 are different, the current of the display element 973 is also different, so that the potential of the first electrode of the display element 973 is different between the first period and the second period. Therefore, the potential of the gate terminal of the transistor 1184 varies at the same time due to capacitive coupling of the capacitor 974. A so-called bootstrap operation is performed.

As described above, various pixels can be used in the display device of the present invention.

Although various pixels are shown in this embodiment, the pixels that can be used in the display device of the present invention are not limited to these pixels.

Note that this embodiment can be freely combined with any description in the other embodiments and examples in this specification. That is, the shift register circuit of the present invention connected to the pixel shown in this embodiment supplies a power supply potential to the output terminal when the transistor is turned on every predetermined time in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

In this embodiment mode, a structure of a display panel having the pixel structure shown in the above embodiment is described with reference to FIGS.

100A is a top view showing the display panel, and FIG. 100B is a cross-sectional view taken along line A-A ′ of FIG. 100A. A signal line control circuit 6701, a pixel portion 6702, a first gate driver 6703, and a second gate driver 6706 indicated by dotted lines are included. Further, a sealing substrate 6704 and a sealing material 6705 are provided, and an inner side surrounded by the sealing material 6705 is a space 6707.

Note that a wiring 6708 is a wiring for transmitting a signal input to the first gate driver 6703, the second gate driver 6706, and the signal line control circuit 6701, and is from an FPC 6709 (flexible printed circuit) serving as an external input terminal. Receives a video signal, a clock signal, a start signal, and the like. On a connection portion between the FPC 6709 and the display panel, an IC chip 6719 (a semiconductor chip on which a memory circuit, a buffer circuit, or the like is formed) is mounted by COG (Chip On Glass) or the like. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The display device in this specification includes not only a display panel body but also a state in which an FPC or a PWB is attached thereto. In addition, it is assumed that an IC chip or the like is mounted.

Next, a cross-sectional structure will be described with reference to FIG. A pixel portion 6702 and its peripheral driver circuits (a first gate driver 6703, a second gate driver 6706, and a signal line control circuit 6701) are formed over the substrate 6710. Here, a signal line control circuit 6701 and A pixel portion 6702 is shown.

Note that the signal line control circuit 6701 includes unipolar transistors such as an N-channel transistor 6720 and an N-channel transistor 6721. Note that by applying the pixel configuration in FIGS. 96 to 99, 118, and 119 to the pixel configuration, the pixel can be configured with a unipolar transistor. Therefore, a unipolar display panel can be manufactured by forming the peripheral driver circuit with N-channel transistors. Of course, a CMOS circuit may be formed using not only a unipolar transistor but also a P-channel transistor.

Note that in the case where the N-channel transistor 6720 and the N-channel transistor 6721 are P-channel transistors, a pixel can be formed using a unipolar transistor by applying the pixel configuration in FIGS. 120 and 121 to the pixel configuration. it can. Therefore, a unipolar display panel can be manufactured by configuring the peripheral driver circuit with P-channel transistors. Of course, a CMOS circuit may be formed using not only a unipolar transistor but also an N-channel transistor.

In this embodiment, a display panel in which a peripheral drive circuit is integrally formed on a substrate is shown. However, this is not always necessary, and all or a part of the peripheral drive circuit is formed on an IC chip and mounted by COG or the like. May be. In that case, the driver circuit does not have to be unipolar, and an N-channel transistor and a P-channel transistor can be used in combination.

The pixel portion 6702 includes a transistor 6711 and a transistor 6712. Note that the source electrode of the transistor 6712 is connected to the first electrode (the pixel electrode 6713). In addition, an insulator 6714 is formed to cover an end portion of the pixel electrode 6713. Here, a positive photosensitive acrylic resin film is used.

In order to improve the coverage, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 6714. For example, in the case where positive photosensitive acrylic is used as a material for the insulator 6714, it is preferable that only the upper end portion of the insulator 6714 has a curved surface with a curvature radius (0.2 μm to 3 μm). As the insulator 6714, either a negative type that becomes insoluble in an etchant by light or a positive type that becomes soluble in an etchant by light can be used.

Over the pixel electrode 6713, a layer 6716 containing an organic compound and a second electrode (counter electrode 6717) are formed. Here, as a material used for the pixel electrode 6713 which functions as an anode, a material having a high work function is preferably used. For example, in addition to single layer films such as ITO (indium tin oxide) film, indium zinc oxide (IZO) film, titanium nitride film, chromium film, tungsten film, Zn film, and Pt film, titanium nitride film and aluminum are mainly used. A laminate of a component film, a three-layer structure of a titanium nitride film, a film containing aluminum as a main component, and a titanium nitride film can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained.

The layer 6716 containing an organic compound is formed by an evaporation method using an evaporation mask or an inkjet method. For the layer 6716 containing an organic compound, a Group 4 metal complex of the periodic table of elements is used as a part thereof, and other materials that can be used in combination include high molecular weight materials even if they are low molecular weight materials. It may be. In addition, as a material used for a layer containing an organic compound, an organic compound is usually used in a single layer or a stacked layer. However, in this embodiment, an inorganic compound is used for a part of a film made of an organic compound. Include. Further, a known triplet material can be used.

Further, as a material used for the counter electrode 6717 formed over the layer 6716 containing an organic compound, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof such as MgAg, MgIn, AlLi, calcium fluoride, Alternatively, calcium nitride may be used. Note that in the case where light generated in the layer 6716 containing an organic compound transmits the counter electrode 6717, the counter electrode 6717 (cathode) is formed using a thin metal film and a transparent conductive film (ITO (indium tin oxide oxide)). An alloy), an indium zinc oxide alloy (In ₂ O ₃ —ZnO), zinc oxide (ZnO), or the like) is preferably used.

Further, a sealing substrate 6704 is attached to a substrate 6710 with a sealant 6705 so that a light-emitting element 6718 is provided in a space 6707 surrounded by the substrate 6710, the seal substrate 6704, and the sealant 6705. Note that the space 6707 includes a structure filled with a sealing material 6705 in addition to a case where the space 6707 is filled with an inert gas (nitrogen, argon, or the like).

Note that an epoxy-based resin is preferably used for the sealant 6705. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like can be used as a material used for the sealing substrate 6704.

As described above, a display panel having the pixel configuration of the present invention can be obtained. Note that the above-described configuration is an example, and the configuration of the display panel of the present invention is not limited to this.

As shown in FIG. 100, the signal line control circuit 6701, the pixel portion 6702, the first gate driver 6703, and the second gate driver 6706 are integrally formed, so that the cost of the display device can be reduced. In this case, since the transistors used for the signal line control circuit 6701, the pixel portion 6702, the first gate driver 6703, and the second gate driver 6706 are unipolar, the manufacturing process can be simplified, so that the manufacturing process can be further reduced. Cost can be reduced.

Note that the structure of the display panel is not limited to the structure in which the signal line control circuit 6701, the pixel portion 6702, the first gate driver 6703, and the second gate driver 6706 are integrally formed as illustrated in FIG. A signal line control circuit 6801 shown in FIG. 101 corresponding to the signal line control circuit 6701 may be formed over an IC chip and mounted on a display panel with COG or the like. Note that the substrate 6800, the pixel portion 6802, the first gate driver 6803, the second gate driver 6804, the FPC 6805, the IC chip 6806, the IC chip 6807, the sealing substrate 6808, and the sealant 6809 in FIG. This corresponds to the substrate 6710, the pixel portion 6702, the first gate driver 6703, the second gate driver 6706, the FPC 6709, the IC chip 6719, the sealing substrate 6704, and the sealant 6705 in FIG.

That is, only a signal control circuit that requires high-speed operation is formed on an IC chip using a CMOS or the like to reduce power consumption. Further, by using a semiconductor chip such as a silicon wafer as the IC chip, higher speed operation and lower power consumption can be achieved.

By forming the first gate driver 6803 and the second gate driver 6804 integrally with the pixel portion 6802, cost reduction can be achieved. Further, the first gate driver 6803, the second gate driver 6804, and the pixel portion 6802 are formed of unipolar transistors, so that further cost reduction can be achieved. As a pixel structure included in the pixel portion 6802, the pixel described in the third embodiment can be used.

Thus, the cost of a high-definition display device can be reduced. Further, by mounting an IC chip on which a functional circuit (memory or buffer) is formed at a connection portion between the FPC 6805 and the substrate 6800, the substrate area can be effectively used.

In addition, the signal line control circuit 6811, the first gate driver 6814, and the first gate driver 6814 in FIG. 101B corresponding to the signal line control circuit 6701, the first gate driver 6703, and the second gate driver 6706 in FIG. Two gate drivers 6813 may be formed on the IC chip and mounted on the display panel by COG or the like. In this case, a high-definition display device can have lower power consumption. Therefore, in order to obtain a display device with lower power consumption, it is preferable to use amorphous silicon for a semiconductor layer of a transistor used in the pixel portion. Note that the substrate 6810, the pixel portion 6812, the FPC 6815, the IC chip 6816, the IC chip 6817, the sealing substrate 6818, and the sealant 6819 in FIG. 101B are the substrate 6710, the pixel portion 6702, the FPC 6709, and the IC in FIG. It corresponds to a chip 6719, a sealing substrate 6704, and a sealing material 6705.

In addition, cost can be reduced by using amorphous silicon for the semiconductor layer of the transistor in the pixel portion 6812. Further, a large display panel can be manufactured.

Further, the second gate driver, the first gate driver, and the signal control circuit may not be provided in the row direction and the column direction of the pixel. For example, a peripheral driver circuit 6901 formed on an IC chip as shown in FIG. 102A is replaced with a first gate driver 6814, a second gate driver 6813, and a signal line control circuit shown in FIG. 6811 may have a function. Note that the substrate 6900, the pixel portion 6902, the FPC 6904, the IC chip 6905, the IC chip 6906, the sealing substrate 6907, and the sealant 6908 in FIG. 102A are the substrate 6710, the pixel portion 6702, the FPC 6709, and the IC in FIG. It corresponds to a chip 6719, a sealing substrate 6704, and a sealing material 6705.

Note that FIG. 102B is a schematic diagram for explaining wiring connection of the display device in FIG. A substrate 6910, a peripheral driver circuit 6911, a pixel portion 6912, an FPC 6913, and an FPC 6914 are included. An external signal and a power supply potential are input from the FPC 6913 to the peripheral driver circuit 6911. The output from the peripheral driver circuit 6911 is input to wirings in the row and column directions connected to the pixels included in the pixel portion 6912.

Further, examples of light-emitting elements applicable to the light-emitting element 6718 are illustrated in FIGS. That is, a structure of a light-emitting element that can be applied to the pixel described in the above embodiment will be described with reference to FIGS.

A light emitting element in FIG. 103A includes an anode 7002 on a substrate 7001, a hole injection layer 7003 made of a hole injection material, a hole transport layer 7004 made of a hole transport material, a light emitting layer 7005, and an electron. In this element structure, an electron transport layer 7006 made of a transport material, an electron injection layer 7007 made of an electron injection material, and a cathode 7008 are stacked. Here, the light emitting layer 7005 may be formed of only one kind of light emitting material, but may be formed of two or more kinds of materials. Further, the structure of the element of the present invention is not limited to this structure.

In addition to the stacked structure in which the functional layers shown in FIG. 103A are stacked, an element using a polymer compound, a high-efficiency element using a triplet light emitting material that emits light from a triplet excited state in a light emitting layer, and the like. The variation is wide. The present invention can also be applied to a white light emitting element obtained by controlling the carrier recombination region by the hole blocking layer and dividing the light emitting region into two regions.

In the element manufacturing method of the present invention shown in FIG. 103A, first, a hole injection material, a hole transport material, and a light emitting material are sequentially deposited on a substrate 7001 having an anode 7002 (ITO). Next, an electron transport material and an electron injection material are vapor-deposited, and finally a cathode 7008 is formed by vapor deposition.

Next, materials suitable for the hole injection material, the hole transport material, the electron transport material, the electron injection material, and the light emitting material are listed below.

As the hole injection material, porphyrin compounds, phthalocyanine (hereinafter referred to as “H ₂ Pc”), copper phthalocyanine (hereinafter referred to as “CuPc”), and the like are effective as long as they are organic compounds. In addition, any material that has a smaller ionization potential than the hole transport material used and has a hole transport function can also be used as the hole injection material. There is also a material obtained by chemically doping a conductive polymer compound, and examples thereof include polyethylenedioxythiophene (hereinafter referred to as “PEDOT”) doped with polystyrene sulfonic acid (hereinafter referred to as “PSS”), polyaniline, and the like. An insulating polymer compound is also effective in terms of planarization of the anode, and polyimide (hereinafter referred to as “PI”) is often used. In addition, inorganic compounds are also used. In addition to metal thin films such as gold and platinum, there are ultra thin films of aluminum oxide (hereinafter referred to as “alumina”).

The most widely used hole transport material is an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond). As widely used materials, 4,4′-bis (diphenylamino) -biphenyl (hereinafter referred to as “TAD”) and its derivative 4,4′-bis [N- (3-methylphenyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as “TPD”), 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as “α-NPD”) ). 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) -triphenylamine (hereinafter referred to as “TDATA”), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) And starburst aromatic amine compounds such as -N-phenyl-amino] -triphenylamine (hereinafter referred to as "MTDATA").

As an electron transport material, a metal complex is often used. Alq, BAlq, tris (4-methyl-8-quinolinolato) aluminum (hereinafter referred to as “Almq”), bis (10-hydroxybenzo [h] -quinolinato) And metal complexes having a quinoline skeleton or a benzoquinoline skeleton such as beryllium (hereinafter referred to as “Bebq”). Further, bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (hereinafter referred to as “Zn (BOX) ₂ ”), bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (hereinafter referred to as “Zn (BOX) ₂ ”) There is also a metal complex having an oxazole-based or thiazole-based ligand such as “Zn (BTZ) ₂ ”). In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (hereinafter referred to as “PBD”), OXD-7, and the like Oxadiazole derivatives of TAZ, 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -23, 4-triazole (hereinafter referred to as “p-EtTAZ”) And phenanthroline derivatives such as bathophenanthroline (hereinafter referred to as “BPhen”) and BCP have electron transport properties.

The electron transport material described above can be used as the electron injection material. In addition, an ultra-thin film of an insulator such as a metal halide such as calcium fluoride, lithium fluoride, or cesium fluoride, or an alkali metal oxide such as lithium oxide is often used. In addition, alkali metal complexes such as lithium acetylacetonate (hereinafter referred to as “Li (acac)”) and 8-quinolinolato-lithium (hereinafter referred to as “Liq”) are also effective.

As the luminescent material, various fluorescent dyes are effective in addition to the metal complexes such as Alq, Almq, BeBq, BAlq, Zn (BOX) ₂ and Zn (BTZ) _{2 described} above. As the fluorescent dye, blue 4,4′-bis (2,2-diphenyl-vinyl) -biphenyl and red-orange 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl)- 4H-pyran and the like. A triplet light emitting material is also possible, and is mainly a complex having platinum or iridium as a central metal. As a triplet light emitting material, tris (2-phenylpyridine) iridium, bis (2- (4′-tolyl) pyridinato-N, C ^{2 ′} ) acetylacetonatoiridium (hereinafter referred to as “acacIr (tpy) ₂ ”), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H porphyrin-platinum and the like are known.

A highly reliable light-emitting element can be manufactured by combining the materials having the functions described above.

Further, as the display element 973 shown in the third embodiment, as shown in FIG. 103 (b), a light emitting element in which layers are formed in the reverse order to FIG. 103 (a) can be used. That is, a cathode 7018 on the substrate 7011, an electron injection layer 7017 made of an electron injection material, an electron transport layer 7016 made of an electron transport material, a light emitting layer 7015, a hole transport layer 7014 made of a hole transport material, and a positive electrode. This is an element structure in which a hole injection layer 7013 made of a hole injection material and an anode 7012 are laminated.

In addition, in order to extract light emitted from the light emitting element, at least one of the anode and the cathode may be transparent. Then, a transistor and a light emitting element are formed over the substrate, and a top emission that extracts light from a surface opposite to the substrate, a bottom emission that extracts light from a surface on the substrate side, and a surface opposite to the substrate side and the substrate. The pixel structure of the present invention can be applied to a light emitting element having any emission structure.

A light-emitting element having a top emission structure will be described with reference to FIG.

A driving TFT 7101 is formed over a substrate 7100, a first electrode 7102 is formed in contact with a source electrode of the driving TFT 7101, and a layer 7103 containing an organic compound and a second electrode 7104 are formed thereover.

The first electrode 7102 is an anode of the light emitting element. The second electrode 7104 is a cathode of the light emitting element. That is, a region where the layer 7103 containing an organic compound is sandwiched between the first electrode 7102 and the second electrode 7104 is a light-emitting element.

Here, as a material used for the first electrode 7102 which functions as an anode, a material having a high work function is preferably used. For example, in addition to a single layer film such as a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film, a stack of titanium nitride and a film containing aluminum as a main component, a film containing a titanium nitride film and aluminum as a main component A three-layer structure of titanium nitride film and the like can be used. Note that with a stacked structure, resistance as a wiring is low, good ohmic contact can be obtained, and a function as an anode can be obtained. By using a metal film that reflects light, an anode that does not transmit light can be formed.

As a material used for the second electrode 7104 functioning as a cathode, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof such as MgAg, MgIn, AlLi, calcium fluoride, or calcium nitride) is used. It is preferable to use a laminate of a metal thin film and a transparent conductive film (ITO (indium tin oxide), indium zinc oxide (IZO), zinc oxide (ZnO), or the like). Thus, a cathode capable of transmitting light can be formed by using a thin metal thin film and a transparent conductive film having transparency.

In this manner, light from the light emitting element can be extracted to the upper surface as indicated by an arrow in FIG. That is, when applied to the display panel in FIG. 100, light is emitted to the sealing substrate 6704 side. Therefore, in the case where a light-emitting element having a top emission structure is used for a display device, the sealing substrate 6704 is a light-transmitting substrate.

In the case where an optical film is provided, an optical film may be provided over the sealing substrate 6704.

Note that the first electrode 7102 can be a metal film made of a material having a low work function, such as MgAg, MgIn, or AlLi, which functions as a cathode. For the second electrode 7104, a transparent conductive film such as an ITO (indium tin oxide) film or indium zinc oxide (IZO) can be used. Therefore, according to this configuration, it is possible to increase the transmittance of top emission.

A light-emitting element having a bottom emission structure will be described with reference to FIG. Since the light-emitting element has the same structure as that in FIG. 104A except for the emission structure, the description will be made using the same reference numerals.

Here, as a material used for the first electrode 7102 functioning as an anode, a material having a high work function is preferably used. For example, a transparent conductive film such as an ITO (indium tin oxide) film or an indium zinc oxide (IZO) film can be used. By using a transparent conductive film having transparency, an anode capable of transmitting light can be formed.

As a material used for the second electrode 7104 functioning as a cathode, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof MgAg, MgIn, AlLi, calcium fluoride, or Ca ₃ N _{2 is used.} Can be used. Thus, by using a metal film that reflects light, a cathode that does not transmit light can be formed.

In this manner, light from the light emitting element can be extracted to the lower surface as indicated by an arrow in FIG. That is, when applied to the display panel of FIG. 100, light is emitted to the substrate 6710 side. Therefore, in the case where a light-emitting element having a bottom emission structure is used for a display device, the substrate 6710 is a light-transmitting substrate.

In the case of providing an optical film, the substrate 6710 may be provided with an optical film.

A light-emitting element having a dual emission structure will be described with reference to FIG. Since the light-emitting element has the same structure as that in FIG. 104A except for the emission structure, the description will be made using the same reference numerals.

Here, as a material used for the first electrode 7102 functioning as an anode, a material having a high work function is preferably used. For example, a transparent conductive film such as an ITO (indium tin oxide) film or an indium zinc oxide (IZO) film can be used. By using a transparent conductive film having transparency, an anode capable of transmitting light can be formed.

As a material used for the second electrode 7104 functioning as a cathode, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof such as MgAg, MgIn, AlLi, calcium fluoride, or calcium nitride) is used. It is preferable to use a stack of a metal thin film and a transparent conductive film (ITO (indium tin oxide), indium zinc oxide alloy (In ₂ O ₃ —ZnO), zinc oxide (ZnO), etc.). Thus, a cathode capable of transmitting light can be formed by using a thin metal thin film and a transparent conductive film having transparency.

In this manner, light from the light emitting element can be extracted on both sides as indicated by arrows in FIG. That is, when applied to the display panel in FIG. 100, light is emitted to the substrate 6710 side and the sealing substrate 6704 side. Therefore, in the case where a light-emitting element having a dual emission structure is used for a display device, both the substrate 6710 and the sealing substrate 6704 are light-transmitting substrates.

In the case where an optical film is provided, the optical film may be provided on both the substrate 6710 and the sealing substrate 6704.

In addition, the present invention can be applied to a display device that realizes full color display using a white light emitting element and a color filter.

As shown in FIG. 105, a base film 7202 is formed over a substrate 7200, a driving TFT 7201 is formed thereon, a first electrode 7203 is formed in contact with the source electrode of the driving TFT 7201, and an organic film is formed thereon. A layer 7204 containing a compound and a second electrode 7205 are formed.

The first electrode 7203 is an anode of the light emitting element. The second electrode 7205 is a cathode of the light emitting element. That is, a region where the layer 7204 containing an organic compound is sandwiched between the first electrode 7203 and the second electrode 7205 is a light-emitting element. 105 emits white light. A red color filter 7206R, a green color filter 7206G, and a blue color filter 7206B are provided above the light-emitting element, so that full color display can be performed. Further, a black matrix (BM7207) for separating these color filters is provided.

The above-described structures of the light-emitting elements can be used in combination and can be used as appropriate for a display device having the pixel structure of the present invention. In addition, the structure of the display panel and the light emitting element described above are examples, and the pixel structure of the present invention can of course be applied to display devices having other structures.

Next, a partial cross-sectional view of a pixel portion of the display panel is shown.

First, the case where a crystalline semiconductor film (polysilicon (p-Si: H) film) is used for a semiconductor layer of a transistor is described with reference to FIGS.

Here, as the semiconductor layer, for example, an amorphous silicon (a-Si) film is formed on a substrate by a known film formation method. Note that the semiconductor film is not limited to an amorphous silicon film and may be a semiconductor film including an amorphous structure (including a microcrystalline semiconductor film). Further, a compound semiconductor film including an amorphous structure such as an amorphous silicon germanium film may be used.

Then, the amorphous silicon film is crystallized by a laser crystallization method, a thermal crystallization method using an RTA or a furnace annealing furnace, or a thermal crystallization method using a metal element that promotes crystallization. Of course, these may be combined.

By the above-described crystallization, a partially crystallized region is formed in the amorphous semiconductor film.

Further, the crystalline semiconductor film partially improved in crystallinity is patterned into a desired shape, and an island-shaped semiconductor film is formed from the crystallized region. This semiconductor film is used for a semiconductor layer of a transistor.

As shown in FIG. 106A, a base film 26102 is formed over a substrate 26101, and a semiconductor layer is formed thereover. The semiconductor layer includes a channel formation region 26103 of the driving transistor 26118 and an impurity region 26105 serving as a source region or a drain region, a channel formation region 26106 serving as a lower electrode of the capacitor 26119, an LDD region 26107, and an impurity region 26108. Note that channel doping may be performed on the channel formation region 26103 and the channel formation region 26106.

As the substrate, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or the like can be used. As the base film 26102, a single layer such as aluminum nitride (AlN), silicon oxide (SiO ₂ ), silicon oxynitride (SiO _x N _y ), or a stacked layer thereof can be used.

Over the semiconductor layer, a gate electrode 26110 and an upper electrode 26111 of a capacitor are formed with a gate insulating film 26109 interposed therebetween.

An interlayer insulator 26112 is formed so as to cover the driving transistor 26118 and the capacitor 26119. A wiring 26113 is in contact with the impurity region 26105 over the interlayer insulator 26112 through a contact hole. A pixel electrode 26114 is formed in contact with the wiring 26113, and a second interlayer insulator 26115 is formed to cover the end portion of the pixel electrode 26114 and the wiring 26113. Here, a positive photosensitive acrylic resin film is used. A layer 26116 containing an organic compound and a counter electrode 26117 are formed over the pixel electrode 26114, and a light-emitting element 26120 is formed in a region where the layer 26116 containing an organic compound is sandwiched between the pixel electrode 26114 and the counter electrode 26117. .

In addition, as illustrated in FIG. 106B, a region 26202 in which an LDD region that forms part of the lower electrode of the capacitor 26119 overlaps with the upper electrode 26111 may be provided. Note that portions common to FIG. 106A are denoted by common reference numerals, and description thereof is omitted.

Further, as shown in FIG. 107A, a second upper electrode 26301 formed in the same layer as the wiring 26113 in contact with the impurity region 26105 of the driving transistor 26118 may be provided. Note that portions common to FIG. 106A are denoted by common reference numerals, and description thereof is omitted. An interlayer insulator 26112 is sandwiched between the second upper electrode 26301 and the upper electrode 26111 to form a second capacitor element. In addition, since the second upper electrode 26301 is in contact with the impurity region 26108, the first capacitor element in which the gate insulating film 26109 is sandwiched between the upper electrode 26111 and the channel formation region 26106, the upper electrode 26111, A second capacitor element including an interlayer insulator 26112 sandwiched between the second upper electrode 26301 and a second capacitor element connected in parallel to form a capacitor element 26302 including the first capacitor element and the second capacitor element. is doing. Since the capacitance of the capacitor 26302 is a combined capacitance obtained by adding the capacitances of the first capacitor and the second capacitor, a capacitor with a large capacity can be formed with a small area. That is, the aperture ratio can be further improved when used as a capacitor having a pixel structure of the present invention.

Alternatively, a structure of a capacitor as shown in FIG. A base film 27102 is formed over the substrate 27101, and a semiconductor layer is formed thereover. The semiconductor layer includes a channel formation region 27103 of the driving transistor 27118 and an impurity region 27105 to be a source region or a drain region. Note that channel doping may be performed in the channel formation region 27103.

As the substrate, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or the like can be used. As the base film 27102, a single layer such as aluminum nitride (AlN), silicon oxide (SiO ₂ ), or silicon oxynitride (SiO _x N _y ) or a stacked layer thereof can be used.

A gate electrode 27107 and a first electrode 27108 are formed over the semiconductor layer with a gate insulating film 27106 interposed therebetween.

A first interlayer insulator 27109 is formed to cover the driving transistor 27118 and the first electrode 27108, and a wiring 27110 is in contact with the impurity region 27105 over the first interlayer insulator 27109 through a contact hole. In addition, a second electrode 27111 in the same layer made of the same material as the wiring 27110 is formed.

Further, a third interlayer insulator 27112 is formed so as to cover the wiring 27110 and the second electrode 27111, and a pixel electrode 27113 is formed on the second interlayer insulator 27112 in contact with the wiring 27110 through a contact hole. Has been. A third electrode 27114 in the same layer made of the same material as the pixel electrode 27113 is formed. Here, a capacitor 27119 including the first electrode 27108, the second electrode 27111, and the third electrode 27114 is formed.

An interlayer insulator 27115 is formed so as to cover end portions of the pixel electrode 27113 and the third electrode 27114, and a layer 27116 containing an organic compound and a counter electrode 27117 are formed over the third interlayer insulator 27115 and the third electrode 27114. In the region where the layer 27116 containing an organic compound is sandwiched between the pixel electrode 27113 and the counter electrode 27117, the light-emitting element 27120 is formed.

As described above, a transistor including a crystalline semiconductor film as a semiconductor layer can have a structure illustrated in FIGS. Note that the structure of the transistor illustrated in FIGS. 106 and 107 is an example of a top-gate transistor. That is, the transistor may be P-type or N-type. In the case of N-type, the LDD region may overlap with the gate electrode, may not overlap with the gate electrode, or may overlap with a part of the LDD region. Further, the gate electrode may have a tapered shape, and an LDD region may be provided in a self-aligned manner below the tapered portion of the gate electrode. Further, the number of gate electrodes is not limited to two, but may be three or more multi-gate structures, or one gate electrode.

By using a crystalline semiconductor film for a semiconductor layer (a channel formation region, a source region, a drain region, or the like) of a transistor included in the pixel of the present invention, for example, the first gate driver 6703 and the second gate driver in FIG. 6706 and the signal line control circuit 6701 can be easily formed integrally with the pixel portion 6702.

In addition, as a transistor structure using polysilicon (p-Si: H) as a semiconductor layer, a structure in which a gate electrode is sandwiched between a substrate and a semiconductor layer, that is, a bottom where the gate electrode is located under the semiconductor layer. A partial cross section of a display panel to which a gate transistor is applied is shown in FIG.

A base film 7502 is formed over the substrate 7501. Further, a gate electrode 7503 is formed over the base film 7502. A first electrode 7504 made of the same material is formed in the same layer as the gate electrode. As a material for the gate electrode 7503, polycrystalline silicon to which phosphorus is added can be used. In addition to polycrystalline silicon, silicide which is a compound of metal and silicon may be used.

A gate insulating film 7505 is formed so as to cover the gate electrode 7503 and the first electrode 7504. As the gate insulating film 7505, a silicon oxide film, a silicon nitride film, or the like is used.

In addition, a semiconductor layer is formed over the gate insulating film 7505. The semiconductor layer includes a channel formation region 7506, an LDD region 7507, and an impurity region 7508 serving as a source region or a drain region of the driver transistor 7522, and a channel formation region 7509 serving as a second electrode of the capacitor 7523, an LDD region 7510, and an impurity region 7511. Have Note that channel doping may be performed on the channel formation region 7506 and the channel formation region 7509.

As the substrate, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or the like can be used. As the base film 7502, a single layer of aluminum nitride (AlN), silicon oxide (SiO ₂ ), silicon oxynitride (SiO _x N _y ), or a stacked layer thereof can be used.

A first interlayer insulator 7512 is formed to cover the semiconductor layer, and a wiring 7513 is in contact with the impurity region 7508 over the first interlayer insulator 7512 through a contact hole. A third electrode 7514 is formed using the same material in the same layer as the wiring 7513. A capacitor 7523 is formed by the first electrode 7504, the second electrode, and the third electrode 7514.

In addition, an opening 7515 is formed in the first interlayer insulator 7512. A second interlayer insulator 7516 is formed so as to cover the driving transistor 7522, the capacitor 7523, and the opening 7515, and a pixel electrode 7517 is formed over the second interlayer insulator 7516 through a contact hole. In addition, an insulator 7518 is formed to cover an end portion of the pixel electrode 7517. For example, a positive photosensitive acrylic resin film can be used. A layer 7519 containing an organic compound and a counter electrode 7520 are formed over the pixel electrode 7517, and a light-emitting element 7521 is formed in a region where the layer 7519 containing an organic compound is sandwiched between the pixel electrode 7517 and the counter electrode 7520. . An opening 7515 is located below the light emitting element 7521. In other words, when light emitted from the light-emitting element 7521 is extracted from the substrate side, the transmittance can be increased because the opening 7515 is provided.

In FIG. 108A, the fourth electrode 7524 may be formed using the same material in the same layer as the pixel electrode 7517 so that the structure shown in FIG. Then, a capacitor 7523 including the first electrode 7504, the second electrode, the third electrode 7514, and the fourth electrode 7524 can be formed.

Next, the case where an amorphous silicon (a-Si: H) film is used for the semiconductor layer of the transistor will be described. FIG. 109 shows the case of a top gate transistor, and FIGS. 110 and 111 show the case of a bottom gate transistor.

FIG. 109A shows a cross section of a forward staggered transistor using amorphous silicon as a semiconductor layer. As shown, a base film 7602 is formed on the substrate 7601. Further, a pixel electrode 7603 is formed over the base film 7602. In addition, a first electrode 7604 made of the same material is formed in the same layer as the pixel electrode 7603.

As the substrate, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or the like can be used. The base film 7602 can be formed using a single layer such as aluminum nitride (AlN), silicon oxide (SiO ₂ ), or silicon oxynitride (SiO _x N _y ), or a stacked layer thereof.

Further, a wiring 7605 and a wiring 7606 are formed over the base film 7602, and an end portion of the pixel electrode 7603 is covered with the wiring 7605. An N-type semiconductor layer 7607 and an N-type semiconductor layer 7608 having an N-type conductivity are formed over the wirings 7605 and 7606. A semiconductor layer 7609 is formed between the wiring 7605 and the wiring 7606 and over the base film 7602. A part of the semiconductor layer 7609 extends to the N-type semiconductor layer 7607 and the N-type semiconductor layer 7608. Note that this semiconductor layer is formed of an amorphous semiconductor film such as amorphous silicon (a-Si: H) or microcrystalline semiconductor (μ-Si: H). In addition, a gate insulating film 7610 is formed over the semiconductor layer 7609. An insulating film 7611 made of the same material and in the same layer as the gate insulating film 7610 is also formed over the first electrode 7604. Note that a silicon oxide film, a silicon nitride film, or the like is used as the gate insulating film 7610.

A gate electrode 7612 is formed over the gate insulating film 7610. A second electrode 7613 made of the same material and in the same layer as the gate electrode is formed over the first electrode 7604 with an insulating film 7611 interposed therebetween. A capacitor element 7619 in which an insulating film 7611 is sandwiched between the first electrode 7604 and the second electrode 7613 is formed. Further, an interlayer insulator 7614 is formed so as to cover an end portion of the pixel electrode 7603, the driving transistor 7618, and the capacitor 7619.

A region 7615 containing an organic compound and a counter electrode 7616 are formed over the interlayer insulator 7614 and the pixel electrode 7603 located in the opening, and the layer 7615 containing an organic compound is sandwiched between the pixel electrode 7603 and the counter electrode 7616 Then, a light emitting element 7617 is formed.

In addition, the first electrode 7604 illustrated in FIG. 109A may be formed using the first electrode 7620 as illustrated in FIG. 109B. The first electrode 7620 is formed using the same material in the same layer as the wirings 7605 and 7606.

FIG. 110 shows a partial cross section of a display panel using a bottom-gate transistor in which amorphous silicon is used for a semiconductor layer.

A base film 7702 is formed over the substrate 7701. Further, a gate electrode 7703 is formed over the base film 7702. A first electrode 7704 made of the same material is formed in the same layer as the gate electrode. As a material for the gate electrode 7703, polycrystalline silicon to which phosphorus is added can be used. In addition to polycrystalline silicon, silicide which is a compound of metal and silicon may be used.

A gate insulating film 7705 is formed so as to cover the gate electrode 7703 and the first electrode 7704. As the gate insulating film 7705, a silicon oxide film, a silicon nitride film, or the like is used.

In addition, a semiconductor layer 7706 is formed over the gate insulating film 7705. In addition, a semiconductor layer 7707 made of the same material is formed in the same layer as the semiconductor layer 7706.

As the substrate, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or the like can be used. The base film 7602 can be formed using a single layer such as aluminum nitride (AlN), silicon oxide (SiO ₂ ), or silicon oxynitride (SiO _x N _y ), or a stacked layer thereof.

N-type semiconductor layers 7708 and 7709 having N-type conductivity are formed over the semiconductor layer 7706, and an N-type semiconductor layer 7710 is formed over the semiconductor layer 7707.

Wirings 7711 and 7712 are formed over the N-type semiconductor layers 7708 and 7709, respectively, and a conductive layer 7713 made of the same material as the wirings 7711 and 7712 is formed over the N-type semiconductor layer 7710.

A second electrode including the semiconductor layer 7707, the N-type semiconductor layer 7710, and the conductive layer 7713 is formed. Note that a capacitor 7720 having a structure in which the gate insulating film 7705 is sandwiched between the second electrode and the first electrode 7704 is formed.

In addition, one end portion of the wiring 7711 extends, and a pixel electrode 7714 is formed in contact with the upper portion of the extended wiring 7711.

An insulator 7715 is formed so as to cover an end portion of the pixel electrode 7714, the driving transistor 7719, and the capacitor 7720.

A layer 7716 containing an organic compound and a counter electrode 7717 are formed over the pixel electrode 7714 and the insulator 7715, and a light-emitting element 7718 is formed in a region where the layer 7716 containing an organic compound is sandwiched between the pixel electrode 7714 and the counter electrode 7717. Has been.

The semiconductor layer 7707 and the N-type semiconductor layer 7710 which are part of the second electrode of the capacitor may not be provided. That is, the capacitor may have a structure in which the second electrode is the conductive layer 7713 and the gate insulating film is sandwiched between the first electrode 7704 and the conductive layer 7713.

Note that in FIG. 110A, the pixel electrode 7714 is formed before the wiring 7711 is formed, so that the second electrode 7721 and the first electrode including the pixel electrode 7714 as illustrated in FIG. 110B are formed. A capacitor 7720 having a structure in which the gate insulating film 7705 is sandwiched between 7704 can be formed.

Note that although an inverted staggered channel-etched transistor is shown in FIG. 110, a channel protective transistor may be used as a matter of course. A case of a transistor having a channel protective structure will be described with reference to FIGS.

A transistor with a channel protective structure shown in FIG. 111A is an insulator 7801 serving as an etching mask over a region where a channel of the semiconductor layer 7706 of the driving transistor 7719 having a channel etch structure shown in FIG. 110A is formed. Are different from each other, and other common parts use common reference numerals.

Similarly, the transistor having the channel protection structure illustrated in FIG. 111B has an etching mask over the region where the channel of the semiconductor layer 7706 of the driving transistor 7719 having the channel etch structure illustrated in FIG. 110B is formed. The difference is that an insulator 7802 is provided, and common points are used for other common parts.

By using an amorphous semiconductor film for a semiconductor layer (a channel formation region, a source region, a drain region, or the like) of a transistor included in the pixel of the present invention, manufacturing cost can be reduced. For example, an amorphous semiconductor film can be applied by using the pixel configuration shown in the third embodiment.

Note that the structure of the transistor to which the pixel structure of the present invention can be applied and the structure of the capacitor are not limited to those described above, and transistors having various structures and structures of capacitors can be used. .

Note that this embodiment can be implemented freely combining with any description in the other embodiments and examples in this specification. That is, the shift register circuit of the present invention connected to the display panel shown in this embodiment supplies a power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

The display device of the present invention can be applied to various electronic devices. Specifically, it can be applied to a display portion of an electronic device. Such electronic devices include video cameras, digital cameras, goggles-type displays, navigation systems, sound playback devices (car audio, audio components, etc.), computers, game devices, portable information terminals (mobile computers, mobile phones, portable games) Or an image reproducing apparatus (specifically, an apparatus having a display capable of reproducing a recording medium such as a digital versatile disc (DVD) and displaying the image). .

FIG. 117A illustrates a display which includes a housing 84101, a support base 84102, a display portion 84103, and the like. A display device having the pixel structure of the present invention can be used for the display portion 84103. The display includes all display devices for displaying information such as for personal computers, for receiving television broadcasts, and for displaying advertisements. A display using the display device having the pixel structure of the present invention for the display portion 84103 can prevent display defects while suppressing power consumption. In addition, cost reduction can be achieved.

In recent years, there is an increasing need for larger displays. And the increase in price has become a problem as the display becomes larger. Therefore, the issue is how to reduce manufacturing costs and keep high-quality products at a low price.

For example, by using the pixel configuration shown in the third embodiment for the pixel portion of the display panel, a display panel including a unipolar transistor can be provided. Therefore, the number of steps can be reduced and the manufacturing cost can be reduced.

In addition, as shown in FIG. 100A, a pixel panel and a peripheral driver circuit are integrally formed, whereby a display panel including a circuit formed of a unipolar transistor can be formed.

Further, by using an amorphous semiconductor (for example, amorphous silicon (a-Si: H)) for a semiconductor layer of a transistor included in a circuit included in the pixel portion, the process can be simplified and further cost reduction can be achieved. In this case, as shown in FIGS. 101B and 102A, a driver circuit around the pixel portion may be formed over the IC chip and mounted on the display panel by COG or the like. In this way, the use of an amorphous semiconductor makes it easy to increase the size of the display.

FIG. 117B shows a camera, which includes a main body 84201, a display portion 84202, an image receiving portion 84203, operation keys 84204, an external connection port 84205, a shutter 84206, and the like.

In recent years, production competition has intensified along with the improvement in performance of digital cameras and the like. And how to keep high-performance products at low prices is important. A digital camera using the display device having the pixel structure of the invention for the display portion 84202 can prevent display defects while suppressing power consumption. In addition, cost reduction can be achieved.

For example, by using the pixel configuration shown in the third embodiment for the pixel portion, a pixel portion formed of a unipolar transistor can be formed. In addition, as shown in FIG. 101A, a signal control circuit with a high operating speed is formed on an IC chip, and a gate driver with a relatively low operating speed is integrated with a circuit composed of a unipolar transistor together with a pixel portion. By forming, high performance can be realized and cost can be reduced. Further, by using an amorphous semiconductor, for example, amorphous silicon, in the pixel portion and a semiconductor layer of a transistor used for a gate driver integrally formed with the pixel portion, cost can be further reduced.

FIG. 117C illustrates a computer, which includes a main body 84301, a housing 84302, a display portion 84303, a keyboard 84304, an external connection port 84305, a pointing device 84306, and the like. A computer using the display device having the pixel structure of the invention for the display portion 84303 can prevent display defects while suppressing power consumption. In addition, cost reduction can be achieved.

FIG. 117D illustrates a mobile computer, which includes a main body 84401, a display portion 84402, a switch 84403, operation keys 84404, an infrared port 84405, and the like. A mobile computer using the display device having the pixel structure of the present invention for the display portion 84402 can prevent display defects while suppressing power consumption. In addition, cost reduction can be achieved.

FIG. 117E illustrates a portable image reproducing device (specifically, a DVD reproducing device) including a recording medium, which includes a main body 84501, a housing 84502, a display portion A 84503, a display portion B 84504, a recording medium reading portion 84505, An operation key 84506, a speaker portion 84507, and the like are included. The display portion A 84503 can mainly display image information, and the display portion B 84504 can mainly display character information. An image reproducing device using the display device having the pixel structure of the present invention for the display portion A 84503 or the display portion B 84504 can prevent display defects while suppressing power consumption. In addition, cost reduction can be achieved.

FIG. 117F illustrates a goggle type display which includes a main body 84601, a display portion 84602, earphones 84603, and a support portion 84604. A goggle type display using the display device having the pixel structure of the present invention for the display portion 84602 can suppress display power while suppressing power consumption. In addition, cost reduction can be achieved.

FIG. 117G illustrates a portable game machine, which includes a housing 84701, a display portion 84702, speaker portions 84703, operation keys 84704, a storage medium insert portion 84705, and the like. A portable game machine in which the display device having the pixel structure of the present invention is used for the display portion 84702 can suppress power consumption and prevent display defects. In addition, cost reduction can be achieved.

FIG. 117H illustrates a digital camera with a television receiving function, which includes a main body 84801, a display portion 84802, operation keys 84803, speakers 84804, a shutter 84805, an image receiving portion 84806, an antenna 84807, and the like. A digital camera with a television receiving function using the display device having the pixel structure of the present invention for the display portion 84802 can prevent display defects while suppressing power consumption. In addition, high-definition display is possible with a high aperture ratio of the pixels. In addition, cost reduction can be achieved.

For example, by using the pixel configuration in FIGS. 96 to 99, 118, and 119 for the pixel portion, the aperture ratio of the pixel can be improved. Specifically, the aperture ratio is improved by using an N-channel transistor as a driving transistor for driving the light-emitting element. Therefore, a digital camera with a television receiving function having a high-definition display portion can be provided.

As described above, a digital camera with a multi-function television receiving function is required to be usable for a long time by one charge while being frequently used for viewing a television.

For example, as shown in FIGS. 101B and 102A, it is possible to reduce power consumption by forming a peripheral driver circuit on an IC chip and using a CMOS or the like.

Thus, the present invention can be applied to all electronic devices.

Note that this embodiment can be implemented freely combining with any description in the other embodiments and examples in this specification. That is, the shift register circuit of the present invention connected to the electronic device shown in this embodiment supplies a power supply potential to the output terminal when the transistor is turned on every predetermined time in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

In this embodiment, a structure example of a cellular phone including a display device using the pixel structure of the present invention in a display portion will be described with reference to FIG.

The display panel 8301 is incorporated in a housing 8330 so as to be detachable. The shape and size of the housing 8330 can be changed as appropriate in accordance with the size of the display panel 8301. A housing 8330 to which the display panel 8301 is fixed is fitted into a printed board 8331 and assembled as a module.

The display panel 8301 is connected to the printed board 8331 through the FPC 8313. A signal processing circuit 8335 including a speaker 8332, a microphone 8333, a transmission / reception circuit 8334, a CPU, a controller, and the like is formed over the printed board 8331. Such a module is combined with the input means 8336 and the battery 8337 and stored in the housing 8339. The pixel portion of the display panel 8301 is arranged so that it can be seen from an opening window formed in the housing 8339.

In the display panel 8301, a pixel portion and some peripheral driver circuits (a driver circuit having a low operating frequency among a plurality of driver circuits) are formed over a substrate using transistors, and some peripheral driver circuits (a plurality of driver circuits) are formed. A driving circuit having a high operating frequency among the circuits) may be formed over the IC chip, and the IC chip may be mounted on the display panel 8301 by COG (Chip On Glass). Alternatively, the IC chip may be connected to the glass substrate using TAB (Tape Automated Bonding) or a printed board. With such a structure, the power consumption of the display device can be reduced, and the usage time by one charge of the mobile phone can be extended. In addition, the cost of the mobile phone can be reduced.

The pixel structure described in the above embodiment can be applied as appropriate to the pixel portion.

For example, by applying the pixel configuration shown in the third embodiment and the like, the pixel portion and the peripheral drive circuit formed integrally with the pixel portion are configured with a unipolar transistor in order to realize cost reduction, thereby reducing the manufacturing process. Can be achieved.

In order to further reduce power consumption, as shown in FIGS. 101 (b) and 102 (a), a pixel portion is formed using a transistor on a substrate, and all peripheral drive circuits are formed on an IC chip. Then, the IC chip may be mounted on the display panel by COG (Chip On Glass) or the like.

Further, the configuration shown in this embodiment is an example of a mobile phone, and the pixel configuration of the present invention is not limited to the mobile phone having such a configuration, and can be applied to mobile phones having various configurations.

Note that this embodiment can be implemented freely combining with any description in the other embodiments and examples in this specification. In other words, the shift register circuit of the present invention included in the mobile phone shown in this embodiment supplies the power supply potential to the output terminal by turning on the transistor at regular intervals in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

In this embodiment, an example of a structure of an electronic device having a display device using the pixel structure of the present invention in a display portion, particularly a television receiver including an EL module will be described.

FIG. 112 shows an EL module in which a display panel 7901 and a circuit board 7911 are combined. A display panel 7901 includes a pixel portion 7902, a scan line driver circuit 7903, and a signal line driver circuit 7904. On the circuit board 7911, for example, a control circuit 7912, a signal dividing circuit 7913, and the like are formed. The display panel 7901 and the circuit board 7911 are connected by a connection wiring 7914. An FPC or the like can be used for the connection wiring.

In the display panel 7901, a pixel portion 7902 and a part of peripheral driver circuits (a driver circuit having a low operating frequency among the plurality of driver circuits) are formed over a substrate using transistors, and a part of the peripheral driver circuits (a plurality of peripheral driver circuits) A driver circuit having a high operating frequency among driver circuits) is formed over an IC chip, and the IC chip is preferably mounted on the display panel 7901 with COG (Chip On Glass) or the like. Alternatively, the IC chip may be mounted on the display panel 7901 using TAB (Tape Automated Bonding) or a printed board.

The pixel structure described in the above embodiment can be applied as appropriate to the pixel portion.

For example, by applying the pixel configuration shown in the third embodiment and the like, the pixel portion and the peripheral drive circuit formed integrally with the pixel portion are configured with a unipolar transistor in order to realize cost reduction, thereby reducing the manufacturing process. Can be achieved.

In order to further reduce power consumption, a pixel portion is formed using a transistor on a glass substrate, all peripheral drive circuits are formed on an IC chip, and the IC chip is formed by COG (Chip On Glass) or the like. You may mount in a display panel.

In addition, by applying the pixel configurations in FIGS. 96 to 99, 118, and 119 of the above embodiment, a pixel can be formed using only an N-channel transistor, so that an amorphous semiconductor (for example, an amorphous semiconductor) Silicon) can be applied to the semiconductor layer of the transistor. That is, a large display device in which it is difficult to manufacture a uniform crystalline semiconductor film can be manufactured. Further, by using an amorphous semiconductor film for a semiconductor layer of a transistor included in a pixel, a manufacturing process can be reduced and a manufacturing cost can be reduced.

Note that in the case where an amorphous semiconductor film is applied to a semiconductor layer of a transistor included in a pixel, a pixel portion is formed using a transistor on a substrate, and all peripheral driver circuits are formed over an IC chip. The IC chip may be mounted on the display panel by COG (Chip On Glass). FIG. 101B shows an example of a structure in which an IC chip in which a pixel portion is formed on a substrate and a peripheral driver circuit is formed on the substrate is mounted by COG or the like.

With this EL module, an EL television receiver can be completed. FIG. 113 is a block diagram illustrating a main configuration of an EL television receiver. A tuner 8001 receives a video signal and an audio signal. The video signal includes a video signal amplifying circuit 8002, a video signal processing circuit 8003 that converts a signal output from the video signal into a color signal corresponding to each color of red, green, and blue, and uses the video signal as input specifications of the drive circuit. Processing is performed by a control circuit 8012 for conversion. The control circuit 8012 outputs a signal to each of the scan line side and the signal line side. In the case of digital driving, a signal dividing circuit 8013 may be provided on the signal line side, and an input digital signal may be divided into m pieces and supplied.

Of the signals received by the tuner 8001, the audio signal is sent to the audio signal amplifier circuit 8004, and the output is supplied to the speaker 8007 via the audio signal processing circuit 8005. The control circuit 8008 receives control information on the receiving station (reception frequency) and volume from the input unit 8009 and sends a signal to the tuner 8001 and the audio signal processing circuit 8005.

FIG. 114A illustrates a television receiver in which an EL module of a different form from that in FIG. 113 is incorporated. In FIG. 114A, a display screen 8102 is formed using an EL module. In addition, a speaker 8103, an operation switch 8104, and the like are provided as appropriate.

FIG. 114B shows a television receiver that can carry only a display wirelessly. A housing and a signal receiver are incorporated in the housing 8112, and the display portion 8113 and the speaker portion 8117 are driven by the battery. The battery can be repeatedly charged by a charger 8110. The charger 8110 can transmit and receive a video signal, and can transmit the video signal to a signal receiver of the display. The housing 8112 is controlled by operation keys 8116. 114B can also be referred to as a video / audio two-way communication device because a signal can be sent from the housing 8112 to the charger 8110 by operating the operation key 8116. FIG. Further, by operating the operation key 8116, a signal is transmitted from the housing 8112 to the charger 8110, and a signal that can be transmitted by the charger 8110 is received by another electronic device, so that communication control of the other electronic device can be performed. It can be said to be a general-purpose remote control device. The present invention can be applied to the display portion 8113.

FIG. 115A shows a module in which a display panel 8201 and a printed wiring board 8202 are combined. The display panel 8201 includes a pixel portion 8203 provided with a plurality of pixels, a first gate driver 8204, a second gate driver 8205, and a signal line driver circuit 8206 for supplying a video signal to the selected pixel. Yes.

The printed wiring board 8202 is provided with a controller 8207, a central processing unit (CPU 8208), a memory 8209, a power supply circuit 8210, an audio processing circuit 8211, a transmission / reception circuit 8212, and the like. The printed wiring board 8202 and the display panel 8201 are connected by a flexible wiring board 8213 (FPC). The printed wiring board 8202 may be provided with a capacitor, a buffer circuit, or the like to prevent noise from being applied to a power supply voltage or a signal or a signal from rising slowly. In addition, the controller 8207, the audio processing circuit 8211, the memory 8209, the CPU 8208, the power supply circuit 8210, and the like can be mounted on the display panel 8201 using a COG (Chip On Glass) method. The scale of the printed wiring board 8202 can be reduced by the COG method.

Various control signals are input and output through an interface unit (I / F unit 8214) provided in the printed wiring board 8202. In addition, an antenna port 8215 for transmitting and receiving signals to and from the antenna is provided on the printed wiring board 8202.

FIG. 115B is a block diagram of the module shown in FIG. This module includes a VRAM 8216, DRAM 8217, flash memory 8218, and the like as the memory 8209. The VRAM 8216 stores image data to be displayed on the panel, the DRAM 8217 stores image data or audio data, and the flash memory 8218 stores various programs.

The power supply circuit 8210 supplies power for operating the display panel 8201, the controller 8207, the CPU 8208, the sound processing circuit 8211, the memory 8209, and the transmission / reception circuit 8212. Depending on the specifications of the panel, the power supply circuit 8210 may be provided with a current source.

The CPU 8208 includes a control signal generation circuit 8220, a decoder 8221, a register 8222, an arithmetic circuit 8223, a RAM 8224, an interface 8219 for the CPU 8208, and the like. Various signals input to the CPU 8208 through the interface 8219 are temporarily stored in the register 8222 and then input to the arithmetic circuit 8223, the decoder 8221, and the like. The arithmetic circuit 8223 performs an operation based on the input signal and designates a place to send various commands. On the other hand, the signal input to the decoder 8221 is decoded and input to the control signal generation circuit 8220. The control signal generation circuit 8220 generates a signal including various commands based on the input signal, and a location specified in the arithmetic circuit 8223, specifically, a memory 8209, a transmission / reception circuit 8212, an audio processing circuit 8211, a controller 8207, and the like. Send to.

The memory 8209, the transmission / reception circuit 8212, the audio processing circuit 8211, and the controller 8207 operate according to the received commands. The operation will be briefly described below.

A signal input from the input unit 8225 is sent to the CPU 8208 mounted on the printed wiring board 8202 via the I / F unit 8214. The control signal generation circuit 8220 converts the image data stored in the VRAM 8216 into a predetermined format in accordance with a signal sent from the input device 8225 such as a pointing device or a keyboard, and sends it to the controller 8207.

The controller 8207 performs data processing on a signal including image data sent from the CPU 8208 in accordance with the panel specifications, and supplies the processed signal to the display panel 8201. The controller 8207 generates an Hsync signal, a Vsync signal, a clock signal CLK, an AC voltage (ACCont), and a switching signal L / R based on the power supply voltage input from the power supply circuit 8210 and various signals input from the CPU 8208. And supplied to the display panel 8201.

In the transmission / reception circuit 8212, signals transmitted / received as radio waves in the antenna 8228 are processed. Specifically, high-frequency signals such as isolators, band-pass filters, VCOs (Voltage Controlled Oscillators), LPFs (Low Pass Filters), couplers, and baluns. Includes circuitry. A signal including audio information among signals transmitted and received in the transmission / reception circuit 8212 is sent to the audio processing circuit 8211 in accordance with a command from the CPU 8208.

A signal including audio information sent in accordance with a command from the CPU 8208 is demodulated into an audio signal by the audio processing circuit 8211 and sent to the speaker 8227. The audio signal sent from the microphone 8226 is modulated by the audio processing circuit 8211 and sent to the transmission / reception circuit 8212 in accordance with a command from the CPU 8208.

The controller 8207, the CPU 8208, the power supply circuit 8210, the sound processing circuit 8211, and the memory 8209 can be mounted as a package of this embodiment.

Of course, the present invention is not limited to a television receiver, and is applied to various uses as a display medium of a particularly large area such as a monitor of a personal computer, an information display board in a railway station or airport, an advertisement display board in a street, etc. can do.

Note that this embodiment can be implemented freely combining with any description in the other embodiments and examples in this specification. In other words, the shift register circuit of the present invention included in the electronic device described in this embodiment supplies a power supply potential to the output terminal when the transistor is turned on every predetermined time in the non-selection period. Thus, a power supply potential is supplied to the output terminal of the shift register circuit through the transistor. Since the transistor is not always turned on during the non-selection period, the shift of the threshold potential of the transistor is suppressed. The power supply potential is supplied to the output terminal of the shift register circuit at regular intervals through the transistor. Therefore, the shift register circuit can suppress the occurrence of noise at the output terminal.

FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 3 shows Embodiment Mode 1; FIG. 5 shows Embodiment Mode 2. FIG. 5 shows Embodiment Mode 2. FIG. 5 shows Embodiment Mode 2. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3. FIG. 5 shows Embodiment Mode 4; FIG. 5 shows Embodiment Mode 4; FIG. 5 shows Embodiment Mode 4; FIG. 5 shows Embodiment Mode 4; FIG. 3 is a diagram illustrating Example 1; FIG. 3 is a diagram illustrating Example 1; FIG. 3 is a diagram illustrating Example 1; FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. 9 shows a seventh embodiment. FIG. 9 shows a seventh embodiment. FIG. 9 shows a seventh embodiment. FIG. 9 shows a seventh embodiment. FIG. 6 shows a sixth embodiment. FIG. 6 shows a fifth embodiment. FIG. FIG. FIG. FIG. FIG. 5 shows Embodiment Mode 4; FIG. 6 shows Embodiment 5. FIG. 4 shows Embodiment 3. FIG. 4 shows Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flip flop circuit 11 Transistor 12 Transistor 13 Transistor 14 Transistor 15 Transistor 16 Transistor 17 Transistor 18 Transistor 19 Capacitance element 70 Flip flop circuit 80 Flip flop circuit 90 Flip flop circuit 91 Resistance element 100 Flip flop circuit 101 Transistor 110 Flip flop circuit 111 Transistor 112 Transistor 113 Transistor 114 Transistor 115 Transistor 116 Transistor 117 Transistor 118 Transistor 119 Capacitance element 120 Flip flop circuit 130 Flip flop circuit 140 Flip flop circuit 150 Flip flop circuit 151 Resistance element 160 Flip flop circuit 161 Transistor 171 Flip-flop circuit 172 Control signal line 173 Control signal line 174 Control signal line 181 Transistor 183 Transistor 200 Shift register circuit 201 Buffer circuit 210 Buffer circuit 211 Inverter circuit 211A Inverter circuit 211B Inverter circuit 220 Buffer circuit 221 NAND circuit 222 Control signal line 230 Buffer Circuit 231 NOR circuit 240 Buffer circuit 250 Buffer circuit 260 Buffer circuit 270 Buffer circuit 280 Inverter circuit 281 Transistor 282 Transistor 290 Inverter circuit 291 Transistor 292 Transistor 293 Transistor 294 Capacitance element 300 Inverter circuit 301 Transistor 310 Inverter circuit 320 Inverter circuit 321 Resistance element 330 Inverter circuit 3 31 Transistor 340 Inverter circuit 341 Transistor 350 Inverter circuit 360 Inverter circuit 370 Inverter circuit 371 Transistor 380 Inverter circuit 390 Inverter circuit 391 Transistor 400 Inverter circuit 401 Transistor 410 Inverter circuit 420 NAND circuit 421 Transistor 422 Transistor 423 Transistor 430 NAND circuit 431 Transistor 432 Transistor 433 Transistor 434 Transistor 435 Capacitance element 440 NAND circuit 441 Transistor 450 NAND circuit 460 NAND circuit 461 Resistance element 470 NAND circuit 471 Transistor 472 Transistor 480 NAND circuit 481 Transistor 490 NAND circuit 500 NOR circuit 501 G Transistor 502 transistor 503 transistor 510 NOR circuit 511 transistor 512 transistor 513 transistor 514 transistor 515 capacitor element 520 NOR circuit 521 transistor 530 NOR circuit 540 NOR circuit 541 resistor element 550 NOR circuit 551 transistor 552 transistor 560 NOR circuit 561 transistor 570 inverter 580 inverter Circuit 581 Transistor 582 Transistor 590 Inverter circuit 591 Transistor 592 Transistor 593 Transistor 594 Capacitor element 600 Inverter circuit 601 Transistor 610 Inverter circuit 620 Inverter circuit 621 Resistive element 630 Inverter circuit 631 Transistor 640 Inverter circuit 641 Transistor 50 inverter circuit 660 inverter circuit 670 inverter circuit 671 transistor 680 inverter circuit 690 inverter circuit 700 inverter circuit 701 transistor 710 inverter circuit 720 NOR circuit 721 transistor 722 transistor 723 transistor 730 NOR circuit 731 transistor 732 transistor 733 transistor 734 transistor 735 capacitor 740 NOR Circuit 741 transistor 750 NOR circuit 760 NOR circuit 761 resistance element 770 NOR circuit 771 transistor 772 transistor 780 NAND circuit 781 transistor 790 NOR circuit 800 NAND circuit 801 transistor 802 transistor 803 transistor 810 NAND circuit 811 transistor 81 2 Transistor 813 Transistor 814 Transistor 815 Capacitance element 820 NAND circuit 821 Transistor 830 NAND circuit 840 NAND circuit 841 Resistance element 850 NAND circuit 851 Transistor 852 Transistor 860 NAND circuit 861 Transistor 870 NAND circuit 880 Shift register circuit 881 Signal line 891 Signal line 892 Signal Line 893 Signal line 901 Transistor 911 Transistor 920 Display device 921 Pixel region 922 Gate driver 923 Control signal line 924 Source signal line 925 Gate signal line 926 FPC
941 Signal line control circuit 942 Control signal line 950 Signal line control circuit 951 Control signal line 952 Control signal line 953 Control signal line 954 Video signal line 955 Source signal line 956 Source signal line 957 Source signal line 960 Pixel 961 Transistor 962 Liquid crystal element 963 Capacitor 964 Counter electrode 965 Common line 970 Pixel 971 Transistor 972 Transistor 973 Display element 974 Capacitor 975 Common electrode 976 Power source line 980 Pixel 990 Pixel 991 Transistor 992 Transistor 993 Transistor 994 Capacitor element 995 Power source line 1180 Pixel 1181 Transistor 1182 Transistor 1183 Transistor 1184 Transistor 1190 Pixel 1200 Pixel 1201 Transistor 1210 Pixel 1211 Transistor 1212 G Njisuta 1241 inverter circuit 1251 inverter circuit 6701 the signal line control circuit 6702 pixel portion 6703 first gate driver 6704 sealing substrate 6705 sealant 6706 second gate driver 6707 space 6708 wiring 6709 FPC
6710 substrate 6711 transistor 6712 transistor 6713 pixel electrode 6714 insulator 6716 layer containing organic compound 6717 counter electrode 6718 light-emitting element 6719 IC chip 6720 N-channel transistor 6721 N-channel transistor 6800 substrate 6801 signal line control circuit 6802 pixel portion 6803 first Gate driver 6804 Second gate driver 6805 FPC
6806 IC chip 6807 IC chip 6808 Sealing substrate 6809 Sealing material 6810 Substrate 6811 Signal line control circuit 6812 Pixel portion 6813 Second gate driver 6814 First gate driver 6815 FPC
6816 IC chip 6817 IC chip 6818 Sealing substrate 6819 Sealing material 6900 Substrate 6901 Peripheral drive circuit 6902 Pixel portion 6904 FPC
6905 IC chip 6906 IC chip 6907 Sealing substrate 6908 Sealing material 6910 Substrate 6911 Peripheral drive circuit 6912 Pixel portion 6913 FPC
6914 FPC
7001 Substrate 7002 Anode 7003 Hole injection layer 7004 Hole transport layer 7005 Light emission layer 7006 Electron transport layer 7007 Electron injection layer 7008 Cathode 7011 Substrate 7012 Anode 7013 Hole injection layer 7014 Hole transport layer 7015 Light emission layer 7016 Electron transport layer 7017 Electron Injection layer 7018 Cathode 7100 Substrate 7101 Driving TFT
7102 Electrode 7103 Layer containing organic compound 7104 Electrode 7200 Substrate 7201 Driving TFT
7202 Base film 7203 Electrode 7204 Layer containing organic compound 7205 Electrode 7206B Color filter 7206G Color filter 7206R Color filter 7207 BM
7501 Substrate 7502 Base film 7503 Gate electrode 7504 Electrode 7505 Gate insulating film 7506 Channel formation region 7507 LDD region 7508 Impurity region 7509 Channel formation region 7510 LDD region 7511 Impurity region 7512 Interlayer insulator 7513 Wiring 7514 Electrode 7515 Opening 7516 Interlayer insulator 7517 Pixel electrode 7518 Insulator 7519 Organic compound layer 7520 Counter electrode 7521 Light-emitting element 7522 Driving transistor 7523 Capacitor element 7524 Electrode 7601 Substrate 7602 Base film 7603 Pixel electrode 7604 Electrode 7605 Wiring 7606 Wiring 7607 N-type semiconductor layer 7608 N-type semiconductor layer 7609 Semiconductor layer 7610 Gate insulating film 7611 Insulating film 7612 Gate electrode 7613 Electrode 7614 Interlayer insulator 7615 Organicization Layer 7616 including object counter electrode 7617 light-emitting element 7618 driver transistor 7619 capacitor element 7620 electrode 7701 substrate 7702 base film 7703 gate electrode 7704 electrode 7705 gate insulating film 7706 semiconductor layer 7707 semiconductor layer 7708 N-type semiconductor layer 7709 N-type semiconductor layer 7710 N Type semiconductor layer 7711 wiring 7712 wiring 7713 conductive layer 7714 pixel electrode 7715 insulator 7716 layer containing organic compound 7717 counter electrode 7718 light emitting element 7719 drive transistor 7720 capacitor element 7721 electrode 7801 insulator 7802 insulator 7901 display panel 7902 pixel portion 7903 scanning Line drive circuit 7904 Signal line drive circuit 7911 Circuit board 7912 Control circuit 7913 Signal division circuit 7914 Connection wiring 8001 Tuner 80 2 Video signal amplification circuit 8003 Video signal processing circuit 8004 Audio signal amplification circuit 8005 Audio signal processing circuit 8007 Speaker 8008 Control circuit 8009 Input unit 8012 Control circuit 8013 Signal division circuit 8101 Housing 8102 Display screen 8103 Speaker 8104 Operation switch 8110 Charger 8112 Housing 8113 Display portion 8116 Operation key 8117 Speaker portion 8201 Display panel 8202 Printed wiring board 8203 Pixel portion 8204 First gate driver 8205 Second gate driver 8206 Signal line driver circuit 8207 Controller 8208 CPU
8209 Memory 8210 Power supply circuit 8211 Audio processing circuit 8212 Transmission / reception circuit 8213 Flexible wiring board 8214 I / F unit 8215 Antenna port 8216 VRAM
8217 DRAM
8218 Flash memory 8219 Interface 8220 Control signal generation circuit 8221 Decoder 8222 Register 8223 Arithmetic circuit 8224 RAM
8225 Input means 8226 Microphone 8227 Speaker 8228 Antenna 8301 Display panel 8313 FPC
8330 Housing 8331 Printed circuit board 8332 Speaker 8333 Microphone 8334 Transmission / reception circuit 8335 Signal processing circuit 8336 Input means 8337 Battery 8339 Housing 8340 Antenna 12201 Power line 12202 Control line 12203 Control line 12204 Control line 12205 Control line 12206 Power line 12207 Output terminal 12208 Semiconductor layer 12209 Gate wiring layer 12210 Wiring layer 12211 Contact layer 26101 Substrate 26102 Base film 26103 Channel formation region 26105 Impurity region 26106 Channel formation region 26107 LDD region 26108 Impurity region 26109 Gate insulating film 26110 Gate electrode 26111 Upper electrode 26112 Interlayer insulator 26113 Wiring 26114 Pixel Electrode 26115 Interlayer insulation 26116 Layer 26117 containing organic compound 26117 Counter electrode 26118 Driving transistor 26119 Capacitor element 26120 Light emitting element 26202 Region 26301 Upper electrode 26302 Capacitor element 27101 Substrate 27102 Base film 27103 Channel formation region 27105 Impurity region 27106 Gate insulating film 27107 Gate electrode 27108 Electrode 27109 Interlayer insulation Object 27110 Wiring 27111 Electrode 27112 Interlayer insulator 27113 Pixel electrode 27114 Electrode 27115 Interlayer insulator 27116 Organic compound layer 27117 Counter electrode 27118 Drive transistor 27119 Capacitor element 27120 Light emitting element 84101 Housing 84102 Support base 84103 Display unit 84201 Main body 84202 Display unit 84203 Image receiver 84204 Operation key 84205 External Continued Port 84206 shutter 84301 body 84302 housing 84303 a display portion 84304 keyboard 84,305 external connection port 84306 pointing device 84401 body 84402 display unit 84403 switches 84404 operating keys 84405 an infrared port 84501 body 84502 housing 84503 display unit A
84504 Display B
84505 Recording medium reading section 84506 Operation key 84507 Speaker section 84601 Main body 84602 Display section 84603 Earphone 84604 Support section 84701 Housing 84702 Display section 84703 Speaker section 84704 Operation key 84705 Storage medium insertion section 84801 Main body 84802 Display section 84803 Operation key 84804 Speaker 8480 84806 Image receiver 84807 Antenna SSP Control signal CK Control signal CKB Control signal SRout Output terminal SRout1 Output terminal SRout2 Output terminal SRout3 Output terminal SRout4 Output terminal SRout5 Output terminal SRoutn Output terminal GDout Output terminal GDout1 Output terminal GDout2 Output terminal GDoutn Output terminal SDout Output terminal SDout1 output terminal Dout2 output terminal SDoutn output terminal SW switches SW1 Switch SW2 switch SW3 switch SSP control signal OUT output terminal

Claims (15)

A first transistor, a second transistor, a third transistor, an inverter, a first wiring, a second wiring, and a third wiring;
The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the first of the inverter. Electrically connected to one terminal,
The second transistor has a first terminal electrically connected to the second wiring, a gate terminal electrically connected to the second terminal of the third transistor,
The third transistor has a first terminal electrically connected to the third wiring, a gate terminal electrically connected to the second terminal of the inverter,
The semiconductor device is characterized in that the gate terminal of the first transistor is electrically connected to a transistor for bringing the gate terminal into a floating state. The first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the first wiring, the second wiring, the third wiring, and the fourth With wiring of
The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the fourth terminal. Electrically connected to the gate terminal of the transistor,
The second transistor has a first terminal electrically connected to the second wiring, a gate terminal electrically connected to the second terminal of the third transistor,
The third transistor has a first terminal electrically connected to the third wiring, and a gate terminal electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor. Connected,
The fourth transistor has a first terminal electrically connected to the second wiring,
The fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring,
The semiconductor device is characterized in that the gate terminal of the first transistor is electrically connected to a transistor for bringing the gate terminal into a floating state. The first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, the first wiring, the second wiring, and the third Wiring, fourth wiring, and fifth wiring,
The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the fourth terminal. Electrically connected to a gate terminal of the transistor and a second terminal of the sixth transistor;
The second transistor has a first terminal electrically connected to the second wiring, a gate terminal electrically connected to the second terminal of the third transistor,
The third transistor has a first terminal electrically connected to the third wiring, and a gate terminal electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor. Connected,
The fourth transistor has a first terminal electrically connected to the second wiring,
The fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring,
The semiconductor device, wherein the sixth transistor has a first terminal electrically connected to the fourth transistor and a gate terminal electrically connected to the fifth wiring. A first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, a first wiring, and a second wiring; Wiring, third wiring, fourth wiring, and fifth wiring,
The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the fourth terminal. Electrically connected to a gate terminal of a transistor, a second terminal of the sixth transistor, and a second terminal of the seventh transistor;
The second transistor has a first terminal electrically connected to the second wiring, and a gate terminal electrically connected to the second terminal of the third transistor and the gate terminal of the seventh transistor. And
The third transistor has a first terminal electrically connected to the third wiring, and a gate terminal electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor. Connected,
The fourth transistor has a first terminal electrically connected to the second wiring,
The fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring,
The sixth transistor has a first terminal electrically connected to the fourth transistor, a gate terminal electrically connected to the fifth wiring,
The seventh transistor has a first terminal electrically connected to the second wiring. A first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a first transistor; A wiring, a second wiring, a third wiring, a fourth wiring, a fifth wiring, and a sixth wiring,
The first transistor has a first terminal electrically connected to the first wiring, a second terminal electrically connected to a second terminal of the second transistor, and a gate terminal connected to the fourth terminal. Electrically connected to a gate terminal of a transistor, a second terminal of the sixth transistor, a second terminal of the seventh transistor, and a second terminal of the eighth transistor;
The second transistor has a first terminal electrically connected to the second wiring, and a gate terminal electrically connected to the second terminal of the third transistor and the gate terminal of the seventh transistor. And
The third transistor has a first terminal electrically connected to the third wiring, and a gate terminal electrically connected to the second terminal of the fourth transistor and the second terminal of the fifth transistor. Connected,
The fourth transistor has a first terminal electrically connected to the second wiring,
The fifth transistor has a first terminal electrically connected to the fourth wiring, a gate terminal electrically connected to the fourth wiring,
The sixth transistor has a first terminal electrically connected to the fourth transistor, a gate terminal electrically connected to the fifth wiring,
The seventh transistor has a first terminal electrically connected to the second wiring,
The semiconductor device, wherein the eighth transistor has a first terminal electrically connected to the second wiring and a gate terminal electrically connected to the sixth wiring. In any one of Claim 2 thru | or 5,
The ratio W / L of the channel length L to the channel width W of the fourth transistor is 10 times or more the ratio W / L of the channel length L to the channel width W of the fifth transistor. apparatus. In any one of Claims 1 thru | or 6,
The semiconductor device, wherein the first transistor and the third transistor have the same conductivity type. In any one of Claims 1 to 7,
The semiconductor device, wherein the first transistor and the fourth transistor are n-channel transistors. In any one of Claims 1 to 8,
A semiconductor device, wherein a capacitor element electrically connected is provided between a second terminal of the first transistor and a gate terminal of the first transistor. In claim 9,
The capacitor element includes a first electrode, a second electrode, and an insulator sandwiched between the first electrode and the second electrode,
The semiconductor device, wherein the first electrode is a semiconductor layer, the second electrode is a gate wiring layer, and the insulator is a gate insulating film. In any one of Claims 1 to 10,
A clock signal is supplied to the first wiring,
A semiconductor device, wherein an inverted clock signal is supplied to the third wiring. A driving circuit including the semiconductor device according to claim 1, a plurality of pixels,
The display device, wherein the pixel is controlled by the driving circuit. In claim 12,
The pixel has a transistor;
The display device, wherein the transistor included in the pixel and the transistor included in the driver circuit have the same conductivity type. In claim 12 or claim 13,
The display device, wherein the pixel is formed over the same substrate as the driving circuit. An electronic apparatus comprising the display device according to claim 12.

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