JP2003029716A - Liquid crystal display device and driving device for the device and driving method of the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, in a liquid crystal display device of a color sequential display system, when the slew rate of the source driver of an operational amplifier system is raised in accordance with a high-speed write-in of a source line, a bias current is increased, too and an LSI(large scale integrated circuit) can not stand heat. SOLUTION: This source driver is made to be able to charge a source line at a high speed while suppressing the generation of heat of an LSI by constituting the source driver of switches. Moreover, the source driver is made to be able to perform multi-level display while making the number of switches minimum by the combined use with a multi-level processing circuit. Furthermore, the liquid crystal display device of the color sequential display system can be realized by using the source driver of this invention.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display control technique for a display device, and more particularly to a technique suitable for writing a video signal to a signal line at a high speed in a matrix type liquid crystal display device.

[0002]

2. Description of the Related Art A color-sequential display system (field-sequential display) in which red, green, or blue images are displayed, and in conjunction with that, illumination according to the respective colors is radiated in any order from the entire surface or the back surface to perform color display. Since a color type liquid crystal display device has to perform display at least three times within one frame, the time for scanning one scanning line is shortened. Therefore, it is necessary to charge the signal line at a high speed, and it is necessary to increase the rate of increase in the output voltage of the signal line driving device (hereinafter referred to as the source driver) (hereinafter referred to as the slew rate). Generally, the conventional source driver is shown in FIG.
It has a circuit configuration using an operational amplifier as shown in FIG.
In FIG. 17, 201, 202, 208 and 209 are current sources, 203, 205 and 207 are FETs, 206 is a signal input terminal, 204 is a power input terminal and 210 is a source line of a liquid crystal panel. In the case of increasing the slew rate in such a circuit, it is realized by increasing the currents of 208 and 209.

[0003]

As described above, it is necessary to increase the slew rate in order to charge the source line at high speed. However, in order to increase the slew rate in the circuit configuration using the operational amplifier, it is necessary to increase the idle current, so that there is a problem that the power consumed inside the source driver increases and the IC heats up. Therefore, for ICs with 200 to 300 ch output channels, the maximum limit is about 10 V / μs,
It was unrealistic in terms of heat generation to make it larger than that.

[0004]

In order to solve this problem, the first invention of the present application provides a voltage input terminal for inputting a plurality of reference voltages, and a video signal input terminal for inputting a video signal. , Which has a switch and a voltage output terminal, and the switch selects one of the plurality of voltage input terminals according to the video signal and outputs the selected voltage input terminal, which is optimal for a color sequential display type liquid crystal display device. The device is realized.

A second aspect of the present invention is a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and a multi-gradation processing. The multi-gradation processing unit performs multi-gradation processing on the video signal, and the switch selects one from the plurality of voltage input terminals according to the multi-gradation processed video signal. By selecting and outputting, a drive device most suitable for a color sequential liquid crystal display device is realized.

Further, a third invention of the present application has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch and a voltage output terminal. However, a color-sequential display type liquid crystal display device is realized by using a drive device that selects and outputs one of the plurality of voltage input terminals according to the video signal.

The fourth invention of the present application is a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and a multi-gradation processing. The multi-gradation processing unit performs multi-gradation processing on the video signal, and the switch selects one from the plurality of voltage input terminals according to the multi-gradation processed video signal. A liquid crystal display device of a color sequential display system is realized by using a driving device which selects and outputs.

A fifth aspect of the present invention is a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch and a voltage formed of low temperature polysilicon. By having one output terminal selected from the plurality of voltage input terminals in accordance with the video signal and outputting the selected output terminal, a drive device optimal for a color sequential display type liquid crystal display device is realized. It is a thing.

The sixth invention of the present application is a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low-temperature polysilicon and a voltage. An output terminal and a multi-gradation processing unit, wherein the multi-gradation processing unit performs multi-gradation processing on the video signal, and then the switch performs the multi-gradation processing according to the multi-gradation processed video signal. By selecting one from the voltage input terminals and outputting the selected voltage, a driving device most suitable for a color sequential display type liquid crystal display device is realized.

Further, a seventh invention of the present application is that a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low-temperature polysilicon and a voltage. A color sequential display type liquid crystal display device is realized by using a drive device that has an output terminal and the switch selects and outputs one from the plurality of voltage input terminals according to the video signal. is there.

The eighth invention of the present application is a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low-temperature polysilicon, and a voltage. An output terminal and a multi-gradation processing unit, wherein the multi-gradation processing unit performs multi-gradation processing on the video signal, and then the switch performs the multi-gradation processing according to the multi-gradation processed video signal. The liquid crystal display device of the color sequential display system is realized by using the driving device which selects and outputs one of the voltage input terminals.

The ninth invention of the present application has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal. The switch includes a source line driving unit that selects and outputs one of the plurality of voltage input terminals according to the video signal, and a processing unit that converts the input video signal into a frequency higher than the original frame frequency. The video signal input by the processing means is converted to a frequency higher than the original frame frequency, and the source line driving means drives the source line according to the converted video signal. is there.

The tenth invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low temperature polysilicon, Source line driving means having a voltage output terminal, wherein the switch selects and outputs one from the plurality of voltage input terminals according to the video signal, and the input video signal with a frequency higher than the original frame frequency. A processing means for converting into a high frequency, the processing means converts the input video signal into a frequency higher than the original frame frequency, and the source line driving means sources in accordance with the converted video signal; It is designed to drive lines.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 16.

(Embodiments of the first and fifth inventions of the present application) As described above, if the charging time assigned to one line becomes short, the source line must be charged at a high speed. This is because if the scanning ends before the source line is charged to a desired voltage, the desired brightness cannot be reached and the display quality is degraded. In the output voltage characteristic of a general source driver, as shown in FIG. 18, the rising rate of the voltage is constant with time. Therefore, it takes several μs to charge the source line to the desired voltage.
It generally takes time. Therefore, in the present invention,
A circuit configuration for charging the source line is formed according to the principle shown in FIG.
Here, 601 is a power source, 602 is a switch, 603 is the resistance of the source line, and 604 is the capacitance of the source line. For example, the source line capacitance is 100 pF and the source line resistance is 1 kΩ.
Assuming that, the time constant is τ (s) = C (F) × R (Ω)
Becomes 0.1 μs, and if it is sufficient to charge up to 99.5% of the desired voltage, the charging time is 5τ, and therefore, 0.1.
1 μs × 5 = 0.5 μs will suffice.

The circuit shown in FIG. 5 is configured by using this as a source driver. Here, 701 to 703 are power supplies, 704 is a switch for selecting one from a plurality of power supplies,
Reference numeral 705 is the resistance of the source line, and 706 is the capacitance of the source line. In this way, by selecting and connecting one of a plurality of power supplies to the source line, gradation expression is possible. If this is expressed by replacing it with a CMOS transistor, the circuit shown in FIG. 1 is obtained. In FIG. 1, 10
1, 113 and 114 are buffer circuits capable of outputting the same voltage as the input voltage, 102, 109 and 110 are transistor control signal input terminals, 103 is a liquid crystal panel source line, and 104, 111 and 112 are Pch and Nch. Analog switches composed of CMOS FETs, 10
5, 106 are reference voltage input terminals, 107 is a voltage dividing resistor, 1
Reference numeral 08 is an inverter that inverts the signal logic. For example,
When an ON signal is input to the input terminal 102, the analog switch indicated by the dotted line 104 is turned on, and the output voltage of the buffer circuit 101 is supplied to the source line 103 of the liquid crystal panel. When an ON signal is input to the input terminal 109, the analog switch indicated by the dotted line 111 turns off.
Then, the output voltage from the buffer circuit 113 is supplied to the source line 103 of the liquid crystal panel.

As described above, the source line can be charged at high speed by connecting the source line to the power source through the switch. Further, in order to express the gradation, one can be selected from a plurality of reference voltages. In addition, the bypass capacitor 1 is connected to the output terminal of the buffer circuit.
If 15 is connected, the current capability of the buffer circuit can be minimized, the degree of freedom in designing can be increased, and display unevenness in brightness due to voltage fluctuation can be suppressed.

Further, FIG. 2 shows an enlarged view of the analog switch. 301 is an inverter for inverting the drive signal of the analog switch, 302 is a Pch transistor, 303
Is an Nch transistor, 304 is a power supply voltage input terminal,
Reference numeral 305 is an output terminal, and 306 is a control signal input terminal of the transistor. By connecting Nch and Pch in parallel in this manner, it is possible to cope with both cases where the source line potential is higher and lower than the power source potential.

A portion where the direction of current flow is known in advance, for example, the reference voltage input terminals 105 and 106.
A transistor having only Pch or Nch may be used as the switch closest to the switch.

Next, FIG. 6 shows a block diagram when a source driver is constructed by using the circuit of FIG. In FIG. 6, reference numeral 801 is a video signal input terminal, 802 is a clock signal input terminal, 803 is a start pulse input terminal for designating a start timing of capturing a video signal in the first latch circuit, and 804 is a second latch circuit from the first latch circuit. Latch pulse input terminal for instructing to transfer a signal to the latch circuit of 801, 805 is a first latch circuit capable of temporarily storing a video signal of one line, and 806 is a video signal of one line similarly. A second latch circuit capable of temporarily storing, 807 is a decoder circuit, 808 is a voltage input terminal of a power supply voltage for driving liquid crystal, 809 is an analog switch, and 810 is an output terminal. When a start pulse is input to 803, the first latch circuit 805 starts accumulating the video signal input from 801. When the video signals for one line have been accumulated, the import is completed.
Next, when a latch pulse is input from 804, the video signal accumulated in the first latch circuit 805 is taken in by the second latch circuit 806. Second latch circuit 806
Holds the captured video signal until the next latch pulse is input. Further, it continues to output the fetched signal to the decoder circuit 807. Since the video signal is n-bit binary data, the decoder circuit selects an appropriate analog switch from among the analog switches to turn on. For example, assuming that the video signal has 5 bits, the number of gradations is 32, so that the decoder circuit selects one of 32 analog switches according to the video signal as shown in FIG. FIG. 8 shows a decoder circuit and a switch circuit portion for one channel of the output terminal. In FIG. 8, 1101 is a decoder circuit, 1102 is a level shifter, and 1103 is an analog switch. Thus, the decoder circuit 1101 is connected to the switch through the level shifter 1102. The level shifter is a circuit that converts an output signal from the decoder circuit into a drive voltage for an analog switch. The decoder circuit turns on any of the analog switches according to the input signal, and outputs any of the power supply voltages V0 to Vk-1 to the output terminal S.

As described above, the level shifters and the switches corresponding to the number of output gradations are prepared for each output terminal, and the switch having the desired voltage level is turned on in accordance with the input signal. Key expression becomes possible. It should be noted that the analog switch 11 uses the output voltage from the decoder circuit 1101.
If 03 can be driven, the level shifter 1102 is unnecessary.

The size of the transistor forming the analog switch is important in determining the time constant.
If the transistor size is large, the current capability is high, so that the source line can be charged at high speed, but the chip size is also increased, and the number of chips that can be taken from one semiconductor wafer is reduced, and the production cost is increased. Therefore, it is important to design the transistor size optimally. The optimum transistor size is obtained by a trade-off between the package size of the source driver and the number of output gradations. As a result of examination by the inventor, the channel length of the transistor is 0.1 μm.
It has been found that when the thickness is within 1.2 μm from m, the ON resistance is suppressed to be low, and the production cost can be minimized while securing the source line charging capability.

With the above configuration, the source line can be charged at a high speed, and a desired video signal can be written in a shorter time than before, and the extra time can be used as the light emission time of illumination. Therefore, it is possible to obtain high-quality display quality without writing insufficiency and at the same time increase brightness. Further, since the operational amplifier is not used, extra power is not constantly consumed and heat generation of the source driver can be suppressed.

Although the line-sequential driving method has been described so far, the present invention can be similarly applied to a dot-sequential driving method using a source line as a sampling capacitor.

Although the case where the source driver is made of normal crystalline silicon has been described so far, the source driver may be formed of low-temperature polysilicon on the substrate of the display device. Further, the voltage generator may be separated into an external circuit instead of being formed of low temperature polysilicon.

By forming the source driver with low-temperature polysilicon on the substrate, in addition to the same effect as the source driver using crystalline silicon described above,
The source driver can be built in the substrate, the cost can be reduced, and the frame of the module can be narrowed.

Needless to say, if the pixel transistor is also formed of low-temperature polysilicon, the video signal can be written at a higher speed.

(Embodiments of the second and sixth inventions of the present application) When the decoders, analog switches, and level shifters corresponding to the number of output grayscales are integrated for each channel of the output terminals, how the current semiconductor process rule becomes fine. It is difficult to say that it has been made 6 per output terminal at most
The limit is about four, and in consideration of manufacturing cost and productivity, it is desirable to reduce the number of gradations. On the other hand, the number of output gray scales of the liquid crystal display device is increasing year by year, and currently, 8-bit (256 gray scale) output is the mainstream. Therefore, an object of the present invention is to improve the display quality by performing multi-gradation processing of video processing while using a source driver having a small number of gradations.

FIG. 9 shows a circuit configuration of the second invention of the present application. Here, the same parts as those in the first invention of the present application are designated by the same reference numerals and the description thereof will be omitted. In FIG. 9, reference numeral 1201 is a multi-gradation processing circuit for performing multi-gradation processing on the video signal. The multi-gradation processing includes inter-frame modulation (FRC), which is generally widely used, dither processing, error diffusion processing, etc. However, here, only the case of inter-frame modulation processing will be described, and dither processing and error Since the diffusion process is known, a detailed description will be omitted.

The inter-frame modulation is to display a gradation corresponding to a gradation between two continuous gradations by combining two continuous gradations using a plurality of frames in an arbitrary pixel. This is a multi-gradation processing method. For example, assuming that the number of output gradations of the source driver is 5 bits (32 gradations) and the number of gradations of the input video signal is 8 bits (256 gradations), the gradations of all the input video signals are Cannot be displayed. Therefore, as shown in FIG. 10, when the input signal does not correspond to the output signal, the gradation to be output is switched for each frame to display an intermediate gradation between the gradations that the source driver can output. For example, if the input video signal has a gradation of 0.5, the video signal is displayed using “8 gradations (corresponding to 3 bits)”, that is, “gradation 0, gradation 1, gradation 0, gradation 1, Key 0, gradation 1, gradation 0, gradation 1 ”are output in this order. Then, the image appears in the eyes of the observer as if "tone 0.5" was output to that pixel. Further, if "gradation 1, gradation 0, gradation 1, gradation 0, gradation 1, gradation 1, gradation 1, gradation 1" is used, "gradation 0.7
5 ”. In this way, by combining adjacent gray scales by using a plurality of frames for display, it is possible to display 249 gray scales even if a source driver having a display capability of only 32 gray scales is used, and almost 8 bits ( Display equivalent to 256 gradations can be realized. Also, as the brightness becomes higher, the human eye becomes insensitive to the brightness change,
As shown in FIG. 11, a plurality of input signals may be expressed by one gradation, that is, brightness, for a portion having a large gradation, that is, a gradation having a high brightness to be displayed. In the case of FIG. 11,
Two gradations are expressed as one gradation with respect to the gradation of the input signal of 241 gradations or more. Although the case where the number of input gradations is 8 bits and the number of output gradations of the source driver is 5 bits has been described as an example, the same method can be used regardless of the number of bits of the input signal or the output signal. It is possible to have multiple gradations.

As described above, according to the present invention, the source line can be charged at high speed, and more gradations can be displayed with a smaller number of output gradations. The multi-gradation processing circuit may be built in the source driver or may be divided into another LSI. When incorporated in the source driver, the wiring capacity for transmitting the video signal becomes small, so that the power consumption of the signal for transmitting the video signal can be reduced, and the use time can be extended when used in a portable device. Also another LS
When divided into I and (for example, a controller), even if the source driver is changed for each model, the same multi-gradation processing circuit can be used, and it can be applied with a small change. .

Although the case where the source driver is connected to the outside of the substrate of the display device has been described so far, the source driver may be formed of low temperature polysilicon on the substrate of the display device. Further, the voltage generator may be separated into an external circuit instead of being formed of low temperature polysilicon.

By forming the source driver from the low temperature polysilicon on the substrate of the display device, in addition to the same effect as the source driver using crystalline silicon, the source driver is built in the substrate of the display device. Therefore, the cost can be reduced. Further, the voltage generator may be separated into an external circuit instead of being formed of low temperature polysilicon.
By doing so, it is possible to reduce the cost and narrow the frame.

(Embodiments of the Third, Fourth, Seventh, and Eighth Inventions of the Present Application) A third invention of the present application realizes a liquid crystal display device by using the source driver according to the first invention of the present application. Is. An overall view is shown in FIG. In FIG. 12, reference numeral 1501 denotes a controller for controlling the source driver, the gate driver, and the back light (backlight), 1
502 is a source driver, 1503 is a gate driver,
Reference numeral 1504 is a liquid crystal display panel, and 1505 is a backlight.

The controller 1501 has a frame memory capable of storing one screen of video signal in order to process the video signal input from the outside into a state suitable for the color sequential display system. The video signal is temporarily stored in the frame memory. Then, it is divided into red, green, and blue video signals and transmitted in order to the source driver with the color order fixed. At the same time, control signals such as a clock signal, a latch pulse, and a start pulse are sent to the source driver. It also sends a control signal required for scanning to the gate driver. This state is shown in FIG. Figure 1
In FIG. 3, 1601 is a red backlight control signal, 1
602 is a green backlight control signal, 1603 is a blue backlight control signal, and 1604, 1605, and 1606 respectively illuminate the backlight during a period in which a voltage is written in the liquid crystal and a period in which the liquid crystal responds to the written voltage. Then, it is a period for displaying the image. Here, as an example, the operation when writing a red video signal will be described. First, in the writing period 1604, a red video signal is written in the liquid crystal panel.
Then, after a period 1605 until the liquid crystal responds to the written voltage, the red backlight is emitted at the timing of the backlight irradiation period 1606. Similarly,
It also processes green and blue video signals. In this way, color display is performed by sequentially displaying each color. In the present invention, by using a source driver capable of writing at high speed, the writing period 1604 can be shortened and the surplus time can be allocated to the backlight irradiation period 1606.
The brightness can be increased.

Next, the control signal of the source driver will be described with reference to FIG. In FIG. 14, 1701 is a video signal for one horizontal scanning period, 1702 is a start pulse for instructing the timing of fetching the video signal into the first latch circuit of the source driver, 1703 is the source from the first latch circuit of the source driver. It is a latch pulse for instructing the timing of delivering the video signal to the second latch circuit of the driver. Further, in FIG. 14, n is the number of scanning lines (gate lines) of the liquid crystal display device. In this way, when the start pulse is input from the controller, the source driver starts to take in the video signal. When a latch pulse is input, the captured video signal is delivered to the second latch circuit, and a voltage corresponding to the video signal delivered to the second latch circuit is output to the source line. this is,
The control is the same as the control of the conventional source driver.

Although the case where the source driver is connected to the outside of the substrate has been described so far, the source driver may be formed on the substrate by low temperature polysilicon. Also,
The voltage generator may not be formed of low-temperature polysilicon but may be separated into an external circuit.

By forming the source driver on the substrate with low-temperature polysilicon, in addition to the same effect as the source driver using crystalline silicon, the source driver can be built in the substrate, which reduces the cost. Is possible.

As described above, according to the third aspect of the present invention, the controller of the conventional color-sequential liquid crystal display device can be used as it is and the source line can be charged faster than the conventional source driver. By using the driver, a long light emission time of the backlight can be secured, so that a liquid crystal display device capable of high-quality and high-luminance display can be obtained.

According to the fourth invention of the present application, the third invention of the present application
In addition to the effect of the invention, it is possible to display more gradations than the source driver can output.
It is possible to obtain a liquid crystal display device capable of high-quality display at low cost.

According to the seventh invention of the present application, the third invention of the present application
In addition to the effects of the invention described above, by forming the source driver on the substrate of the display device with low-temperature polysilicon, a liquid crystal display device with lower cost, a narrower frame, and higher quality display can be obtained. .

According to the eighth invention of the present application, the fourth invention of the present application
In addition to the effects of the invention described above, by forming the source driver on the substrate of the display device with low-temperature polysilicon, a liquid crystal display device with lower cost, a narrower frame, and higher quality display can be obtained. .

(Embodiments of the ninth and tenth inventions of the present application) The color sequential display method is a method of displaying red, green and blue images in order and performing color display. Since the luminescent colors of are dispersed over time, a so-called color breakage phenomenon occurs, in which when a moving image is displayed, the color shifts when followed by the eyes, which is a factor that deteriorates the display quality.

The shorter the light emission interval of each color is, the smaller the spatial color shift visually perceived and the less noticeable the color splitting phenomenon becomes. Therefore, for example, as shown in FIG. 15, images of each color of red, green, blue, red, green, and blue may be displayed twice in one frame period.

A circuit configuration for realizing this is shown in FIG. Reference numeral 1801 is a video signal input terminal, 1802 is a frame memory which is a storage means capable of storing at least one screen of video signal, and 1803 is a signal in a state optimal for a color sequential display method or a frame frequency conversion of the video signal Computation means for processing, 1804 is a source driver for driving a source line, 1805 is a liquid crystal display device, 18
Reference numeral 06 is an oscillator for generating a clock signal, 1807 is a signal line for setting a clock cycle for the oscillator 1806, and 1808 is a signal line for a clock signal generated by the oscillator 1806.

The video signal input from 1801 is input to the arithmetic means 1803, and the arithmetic means 1803 sends the video signal to the frame memory 1802 and temporarily stores it.

When the video signals for one screen are stored,
The calculation means 1803 reads the video signal from the frame memory 1802. For example, in the case where red, green, blue, red, green, and blue are read six times within one frame period as the color breakup reduction processing, the calculation unit 1803 uses the oscillator 1806.
To 6 is sent.

Then, the oscillator 1806 generates a clock signal having a frequency six times as high as the input video signal, and the arithmetic means 1
A clock signal is sent to 803 through a signal line 1807. The calculation means 1803 sequentially reads the red, green, and blue video signals from the frame memory 1802 based on the clock signal sent, and the source driver 1
Send to 804. The source driver 1804 drives the source line of the liquid crystal display device 1805 based on the received video signal.

In order to display the video signal six times, the source line must be charged so fast. Therefore, in the present invention, the source driver according to the first invention of the present application is used as the source driver. As a result, the time for writing red, green, and blue images on the liquid crystal in one frame period can be shortened.

Up to now, one frame includes red, green, blue,
The case of displaying red, green, and blue has been described as an example, but in the present invention, 1/3 of one frame period of the input signal is set as one subframe, and four or more subframes are displayed in one frame period to display each color. The display method is not limited to any of the above, since it is characterized by narrowing the light emission interval of (1) and using the source driver of the first invention of the present application to realize it. For example, a method of displaying red, green, and blue in the first half of the frame and displaying black in the second half of the frame, or a method of displaying red, green, blue, green, and red may be used.

Further, when the fifth invention or the sixth invention of the present application, that is, the source driver formed on the substrate by low-temperature polysilicon is used as the source driver, color breakage can be reduced and the source driver can be used as a display device. Can be formed on the substrate, and the frame can be narrowed and the cost can be reduced.

[0052]

As described above, according to the first aspect of the present invention, a voltage input terminal for inputting a plurality of reference voltages,
By having a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal, the switch selects and outputs one from the plurality of voltage input terminals according to the video signal. In addition, the source line can be charged at high speed, the heat generation of the source driver can be suppressed, and an optimum driving device for a color sequential liquid crystal display device can be realized.

Further, according to the second invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and After the multi-gradation processing unit performs multi-gradation processing on the video signal, the switch has a gradation processing unit,
By selecting and outputting one from the plurality of voltage input terminals according to the multi-gradation processed video signal, the source line can be charged at high speed and heat generation of the source driver can be suppressed. In addition, the number of gradations that can be displayed is greater than the number of gradations that can be output by the driving device of the liquid crystal display device, and the optimum driving device for the liquid crystal display device of the color sequential display system can be realized. There is.

According to the third invention of the present application, it has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal. By using a drive device in which the switch selects and outputs one from the plurality of voltage input terminals according to the video signal, it becomes possible to charge the source line to a desired voltage in a short time, There is an effect that it is possible to realize a high-quality display color sequential display type liquid crystal display device with good color reproducibility.

According to the fourth invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and a multi-gradation. The multi-gradation processing unit performs multi-gradation processing on the video signal, and the switch operates from the plurality of voltage input terminals according to the multi-gradation processed video signal. A high-quality color sequential display type liquid crystal display device with good color reproducibility that can display more gray scales than the source driver can output by using a driving device that selects and outputs two gray scales. The effect is that it can be realized at low cost.

According to the fifth aspect of the present invention, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, and a switch made of low temperature polysilicon. A source output line, wherein the switch has a voltage output terminal, and the switch selects one from the plurality of voltage input terminals according to the video signal and outputs the selected voltage input terminal. It is possible to suppress the heat generation of the liquid crystal display device, and it is possible to realize an optimal driving device for a liquid crystal display device of a color sequential display system.

According to the sixth aspect of the present invention, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, and a switch made of low-temperature polysilicon. And a voltage output terminal and a multi-gradation processing unit, wherein the multi-gradation processing unit performs multi-gradation processing on the video signal, and then the switch switches to the multi-gradation processed video signal. Accordingly, by selecting and outputting one from the plurality of voltage input terminals, the source line can be charged at high speed, heat generation of the source driver can be suppressed, and the liquid crystal display device It is possible to display a larger number of gradations than the number of gradations that can be output by the driving device, and it is possible to realize an optimum driving device for a liquid crystal display device of a color sequential display system.

According to the seventh invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, and a switch made of low-temperature polysilicon. And a voltage output terminal, wherein the switch selects one of the plurality of voltage input terminals according to the video signal and outputs the selected voltage, so that the source line can have a desired voltage in a short time. Therefore, there is an effect that it is possible to realize high-quality color sequential display type liquid crystal display device with good color reproducibility.

According to the eighth invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, and a switch formed of low-temperature polysilicon. And a voltage output terminal and a multi-gradation processing unit, and the multi-gradation processing unit performs multi-gradation processing on the video signal, and then the switch responds to the multi-gradation processed video signal. By using a driving device that selects and outputs one from the plurality of voltage input terminals, it is possible to display more gradations than the source driver can output. The liquid crystal display device of the sequential display system can be realized at low cost.

According to the ninth invention of the present application, it has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal. Source line driving means for the switch to select and output one of the plurality of voltage input terminals according to the video signal, and processing for converting the input video signal to a frequency higher than the original frame frequency By converting the video signal input by the processing means to a frequency higher than the original frame frequency, and driving the source line according to the converted video signal by the source line driving means, In a color sequential display type liquid crystal display device, color breakup can be reduced.

According to the tenth invention of the present application, a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, and a switch formed of low-temperature polysilicon. A source line driving means having a voltage output terminal, wherein the switch selects and outputs one from the plurality of voltage input terminals according to the video signal,
It has a processing means for converting the input video signal into a frequency higher than the original frame frequency, and by the processing means,
In the liquid crystal display device of the color sequential display system, by converting the input video signal into a frequency higher than the original frame frequency and driving the source line according to the converted video signal by the source line driving means. In addition to reducing color breakage, the source line driving means can be formed on the substrate, so that the frame and the cost can be reduced.

If the first to tenth aspects of the present invention are used, unnecessary bias current is not consumed, so that power consumption can be reduced and the global environment,
It will be friendly to the space environment.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a source driver according to the first invention, the second invention, the fifth invention, or the sixth invention.

FIG. 2 is a diagram showing one analog switch in the basic configuration of the source driver according to the first invention, the second invention, the fifth invention, or the sixth invention.

FIG. 3 is a diagram showing source line charging characteristics of a source driver according to the present invention.

FIG. 4 is a diagram showing the principle of the first invention, the second invention, the fifth invention, or the sixth invention.

FIG. 5 is a diagram showing the principle of the first invention, the second invention, the fifth invention, or the sixth invention.

FIG. 6 is a diagram showing a block diagram of a source driver according to the first invention or the fifth invention.

FIG. 7 is a diagram showing a correspondence relationship between input signals and switches.

FIG. 8 is a block diagram of a switch unit.

FIG. 9 is a block diagram of a source driver according to the second or sixth invention of the present application.

FIG. 10 is an explanatory diagram of interframe modulation.

FIG. 11 is an explanatory diagram of interframe modulation.

FIG. 12 is a block diagram of a liquid crystal display device according to a third invention, a fourth invention, a seventh invention, or an eighth invention.

FIG. 13 is a diagram showing the operations of the controller and the backlight of the liquid crystal display device according to the third or fourth invention of the present application or the seventh or eighth invention of the present application.

FIG. 14 is a diagram showing the operations of the controller and the source driver of the liquid crystal display device according to the third, fourth, or seventh or eighth invention of the present application.

FIG. 15 is a diagram showing a driving method for reducing color breakup.

FIG. 16 is a diagram showing a circuit configuration for realizing the driving method of the liquid crystal display device according to the ninth or tenth invention of the present application.

FIG. 17 is a diagram showing a basic configuration of a conventional operational amplifier type source driver.

FIG. 18 is a diagram showing source line charging characteristics of an operational amplifier type source driver.

[Explanation of symbols]

101, 113, 114 Buffer circuits 102, 109, 110 Transistor control signal input terminal 103 Liquid crystal panel source lines 104, 111, 112 Analog switches 105, 106 Reference voltage input terminal 107 Voltage dividing resistor 108 Inverter 115 Bypass capacitor

Front page continuation (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) G09G 3/20 623 G09G 3/20 623B 641 641E 641H 3/34 3/34 JF term (reference) 2H093 NA54 NA55 NA64 ND06 ND39 5C006 AA12 AA14 AA22 AF44 BB16 BC06 BC11 BC16 FA47 FA56 5C080 AA10 BB05 CC03 DD22 DD26 DD27 FF11 JJ02 JJ03 JJ05

Claims (58)

[Claims] 1. A video signal input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal, wherein the switch is provided for the video signal. A driving device for a liquid crystal display device of a color sequential display system, wherein one of the plurality of voltage input terminals is selected and output according to the selected voltage input terminal. 2. A buffer circuit configured to output the same signal as an externally input signal between the voltage input terminal and the switch.
A driving device for the liquid crystal display device according to item 1. 3. The drive device for a liquid crystal display device according to claim 2, wherein a bypass capacitor is connected to the output of the buffer circuit. 4. The switch is a CMOS of Pch and Nch.
The driving device for the liquid crystal display device according to claim 1, wherein the driving device is constituted by an FET. 5. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and a multi-gradation processing section, After the multi-gradation processing unit performs multi-gradation processing on the video signal, the switch selects and outputs one from the plurality of voltage input terminals according to the multi-gradation processed video signal. A drive device for a liquid crystal display device of a color sequential display system characterized by the above. 6. A buffer circuit configured to output the same signal as an externally input signal between the voltage input terminal and the switch.
A driving device for the liquid crystal display device according to item 1. 7. The drive device for a liquid crystal display device according to claim 6, wherein a bypass capacitor is connected to the output of the buffer circuit. 8. The switch is a CMOS of Pch and Nch.
The driving device of the liquid crystal display device according to claim 5, wherein the driving device is formed of a FET. 9. Multi-gradation processing is performed by interframe modulation (FR).
The liquid crystal display device according to claim 5, which is C). 10. The liquid crystal display device according to claim 5, wherein the multi-gradation processing is dither processing. 11. The liquid crystal display device according to claim 5, wherein the multi-gradation processing is error diffusion processing. 12. Multi-gradation processing is performed by interframe modulation (FR).
6. The liquid crystal display device according to claim 5, which is a combination of at least two of C) or dither processing or error diffusion processing. 13. A video signal input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal, wherein the switch is provided for the video signal. A liquid crystal display device of a color sequential display system characterized by using a driving device which selects and outputs one from the plurality of voltage input terminals in response. 14. The liquid crystal display device according to claim 13, further comprising a buffer circuit between the voltage input terminal and the switch, the buffer circuit configured to output the same signal as an externally input signal. . 15. The bypass capacitor is connected to the output of the buffer circuit.
The liquid crystal display device according to item 1. 16. The switch is a CMO of Pch and Nch.
14. The semiconductor device according to claim 13, which is composed of an S FET.
The liquid crystal display device according to item 1. 17. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, a voltage output terminal, and a multi-gradation processing section, After the multi-gradation processing unit performs multi-gradation processing on the video signal, the switch selects and outputs one from the plurality of voltage input terminals according to the multi-gradation processed video signal. A color-sequential display type liquid crystal display device characterized by using a driving device. 18. The liquid crystal display device according to claim 17, further comprising a buffer circuit arranged between the voltage input terminal and the switch so as to output the same signal as the signal input from the outside. . 19. A bypass capacitor is connected to the output of the buffer circuit.
The liquid crystal display device according to item 1. 20. The switch is a CMO of Pch and Nch.
18. The semiconductor device according to claim 17, which is composed of an S FET.
The liquid crystal display device according to item 1. 21. Multi-gradation processing is performed by inter-frame modulation (FR).
The liquid crystal display device according to claim 17, which is C). 22. The liquid crystal display device according to claim 17, wherein the multi-gradation processing is dither processing. 23. The liquid crystal display device according to claim 17, wherein the multi-gradation processing is error diffusion processing. 24. Inter-frame modulation (FR)
18. The liquid crystal display device according to claim 17, wherein at least two or more of C) or dither processing or error diffusion processing are combined. 25. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low temperature polysilicon, and a voltage output terminal, The driving device of a color sequential display type liquid crystal display device, wherein the switch selects and outputs one of the plurality of voltage input terminals according to the video signal. 26. The liquid crystal display device according to claim 25, further comprising a buffer circuit configured to output the same signal as an externally input signal between the voltage input terminal and the switch. Drive. 27. A bypass capacitor is connected to the output of the buffer circuit.
A driving device for the liquid crystal display device according to item 1. 28. The switch is a CMO of Pch and Nch.
26. It is comprised by SFET.
A driving device for the liquid crystal display device according to item 1. 29. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low-temperature polysilicon, a voltage output terminal, and a multi-story. A tone processing unit, wherein the multi-gradation processing unit performs multi-tone processing on the video signal, and then the switch is operated from the plurality of voltage input terminals in accordance with the multi-tone processed video signal. A driving device for a liquid crystal display device of a color sequential display system, which selects and outputs one. 30. The liquid crystal display device according to claim 29, further comprising a buffer circuit between the voltage input terminal and the switch, the buffer circuit configured to output the same signal as an externally input signal. Drive. 31. A bypass capacitor is connected to the output of the buffer circuit.
A driving device for the liquid crystal display device according to item 1. 32. The switch is a CMO of Pch and Nch.
30. An S-FET is used for the configuration.
A driving device for the liquid crystal display device according to item 1. 33. Multi-gradation processing is performed by interframe modulation (FR).
30. The liquid crystal display device according to claim 29, which is C). 34. The liquid crystal display device according to claim 29, wherein the multi-gradation processing is dither processing. 35. The liquid crystal display device according to claim 29, wherein the multi-gradation processing is error diffusion processing. 36. Inter-frame modulation (FR)
30. The liquid crystal display device according to claim 29, which is a combination of C) or at least two dithering processes or error diffusion processes. 37. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low temperature polysilicon, and a voltage output terminal, A color-sequential display type liquid crystal display device, wherein the switch uses a driving device that selects and outputs one from the plurality of voltage input terminals according to the video signal. 38. The liquid crystal display device according to claim 37, further comprising a buffer circuit between the voltage input terminal and the switch, the buffer circuit configured to output the same signal as an externally input signal. . 39. The bypass capacitor is connected to the output of the buffer circuit.
The liquid crystal display device according to item 1. 40. The switch is a CMO of Pch and Nch.
38. The structure according to claim 37, comprising an S FET.
The liquid crystal display device according to item 1. 41. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low temperature polysilicon, a voltage output terminal, and a multi-story. A tone processing unit, wherein the multi-gradation processing unit performs multi-tone processing on the video signal, and then the switch is operated from the plurality of voltage input terminals in accordance with the multi-tone processed video signal. A color-sequential display type liquid crystal display device characterized by using a driving device for selecting and outputting one. 42. The liquid crystal display device according to claim 41, further comprising a buffer circuit between the voltage input terminal and the switch, the buffer circuit configured to output the same signal as an externally input signal. . 43. A bypass capacitor is connected to the output of the buffer circuit.
The liquid crystal display device according to item 1. 44. The switch is a CMO of Pch and Nch.
42. An S FET is formed.
The liquid crystal display device according to item 1. 45. Inter-frame modulation (FR)
The liquid crystal display device according to claim 41, which is C). 46. The liquid crystal display device according to claim 41, wherein the multi-gradation processing is dither processing. 47. The liquid crystal display device according to claim 41, wherein the multi-gradation processing is error diffusion processing. 48. Inter-frame modulation (FR)
42. The liquid crystal display device according to claim 41, which is a combination of at least two of C) or dither processing or error diffusion processing. 49. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal, wherein the switch is provided for the video signal. A source line driving means for selecting and outputting one from the plurality of voltage input terminals, and a processing means for converting the input video signal into a frequency higher than the original frame frequency. A liquid crystal display of a color sequential display system, characterized in that an input video signal is converted to a frequency higher than the original frame frequency and the source line is driven by the source line driving means in accordance with the converted video signal. Device driving method. 50. The source line driving means has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal. The driving method of a color sequential display type liquid crystal display device according to claim 49. 51. The color sequential display according to claim 50, further comprising a buffer circuit arranged between the voltage input terminal and the switch so as to output the same signal as the signal input from the outside. Method for driving liquid crystal display device. 52. A bypass capacitor is connected to the output of the buffer circuit.
7. A method for driving a liquid crystal display device of the color sequential display method described in. 53. The switch is a CMO of Pch and Nch.
50. The S-FET is formed.
7. A method for driving a liquid crystal display device of the color sequential display method described in. 54. A voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch formed of low temperature polysilicon, and a voltage output terminal, A source line driving means for the switch to select and output one from the plurality of voltage input terminals according to the video signal, and a processing means for converting the input video signal to a frequency higher than the original frame frequency. And converting the video signal input by the processing unit to a frequency higher than the original frame frequency, and driving the source line according to the converted video signal by the source line driving unit. Driving method of liquid crystal display device of color sequential display method. 55. The source line driving means has a voltage input terminal for inputting a plurality of reference voltages, a video signal input terminal for inputting a video signal, a switch, and a voltage output terminal. The method for driving a liquid crystal display device of a color sequential display system according to claim 54. 56. The color sequential display according to claim 55, further comprising a buffer circuit configured to output the same signal as an externally input signal between the voltage input terminal and the switch. Method for driving liquid crystal display device. 57. A bypass capacitor is connected to the output of the buffer circuit.
7. A method for driving a liquid crystal display device of the color sequential display method described in. 58. The switch is a CMO of Pch and Nch.
55. The S-FET is formed.
7. A method for driving a liquid crystal display device of the color sequential display method described in.