KR20090080357A - Device for controlling black luminance using voltage booster and display using the same - Google Patents

Abstract

A device for controlling black luminance using a voltage booster and a display using the same are provided to improve the picture quality by reducing the black brightness. A device for controlling black luminance using a voltage booster comprises a booster voltage storage and a sub pixel. The booster voltage storage is positioned at the input terminal of the data line(DL) and stores the predetermined booster voltage. The sub pixel is positioned at the cross point of the gate line(GL) and the data line. The sub pixel generates the light according to the sum value of data voltage and booster voltage. The data voltage and the booster voltage are supplied to the data line. A display device(400) is performed to improve the picture quality using the booster voltage storage and the sub pixel.

Description

DEVICE FOR CONTROLLING BLACK LUMINANCE USING VOLTAGE BOOSTER AND DISPLAY USING THE SAME}

The present invention relates to a display device, and more particularly, to an apparatus for improving black brightness in a display device.

Recently, various flat panel display devices have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such a flat panel display device may be a liquid crystal display device (hereinafter referred to as "LCD"), a field emission display device (hereinafter referred to as "FED"), a plasma display panel (below, And the electro-luminescence (hereinafter referred to as "EL") display element.

Among them, PDP is attracting attention as the most advantageous display device for light and small size and large screen because of its simple structure and manufacturing process, but it has the disadvantages of low luminous efficiency, low luminance and high power consumption. In contrast, an active matrix LCD having a thin film transistor (hereinafter, referred to as “TFT”) as a switching element has a disadvantage in that large screens are difficult to use due to the semiconductor process and power consumption is large due to the backlight unit. In addition, the LCD has a large optical loss and a narrow viewing angle due to optical elements such as a polarizing filter, a prism sheet, and a diffusion plate.

On the other hand, the EL display device is classified into an inorganic EL display device and an organic EL display device according to the material of the light emitting layer. The EL display device is a self-light emitting device that emits light by itself, and thus has an advantage of fast response speed and high luminous efficiency, luminance, and viewing angle. In comparison with the organic EL display device, the inorganic EL display device has higher power consumption and cannot obtain high luminance, and cannot emit various colors of R (Red), G (Green), and B (Blue). On the other hand, the organic EL display device is driven at a low DC voltage of several tens of volts, has a fast response speed, high luminance, and has the advantage of emitting various colors of R, G, and B.

1 is a diagram illustrating a light emission principle of a conventional organic light emitting display device.

As illustrated in FIG. 1, when a voltage is applied between the first electrode 100 and the second electrode 110, the electrons generated from the second electrode 110 may be formed of an electron injection layer. 120a) and the electron transport layer 120b are moved toward the light emitting layer 120c. Further, holes generated from the first electrode 100 are transferred to the light emitting layer 120c through the hole injection layer 120d and the hole transport layer 120d. To the side. Accordingly, in the light emitting layer 120c, light is generated by collision and recombination of electrons and holes supplied from the electron transport layer 120b and the hole transport layer 120d, and the light is emitted to the outside through the first electrode 100. The image is displayed.

FIG. 2 is an equivalent circuit diagram of a subpixel of a conventional P-type organic light emitting display device. 3 is a driving waveform diagram of a general type organic light emitting display device.

As illustrated in FIG. 2, the organic light emitting display device includes subpixels 200 arranged in regions defined by intersections of the gate line GL and the data line DL. The sub-pixel 200 receives the data voltage DATA from the data line DL when the scan voltage SCAN is supplied to the gate line GL, and emits light with light corresponding to the data voltage DATA. Is displayed.

To this end, the sub-pixel 200 is a cell driver 210 connected to a gate line GL, a data line DL, a supply voltage source VDD, and connected to an anode electrode of an EL cell OEL, and the cell driver An EL cell OEL is connected between the 210 and the ground voltage source GND. The cell driver 210 includes a switching TFT T1, a driving TFT T2, and a capacitor C.

In particular, a P-type organic light emitting display device uses an N-type substrate, and the switching TFT T1 and the driving TFT T2 are P-type metals having a hole in a carrier. It is formed of an oxide semiconductor (Metal Oxide Semiconducter Field Effect Transistor).

The switching TFT T1 is turned on when the scan low voltage SCAN low is supplied to the gate line GL, thereby switching the data low voltage DATA low supplied to the data line DL to the node N. FIG. Supplies). The data low voltage DATA low supplied to the node N is charged to the capacitor C and supplied to the gate terminal of the driving TFT T2. The driving TFT T2 controls the amount of light emission of the EL cell OEL by controlling the amount of current I supplied from the supply voltage source VDD to the EL cell OEL in response to the data low voltage DATA low supplied to the gate terminal. Will be adjusted.

In addition, since the data low voltage DATA low charged in the capacitor C is discharged even when the switching TFT T1 is turned off, the driving TFT T1 is the data f low voltage DATA low of the next frame. Current I from the supply voltage source VDD is supplied to the EL cell OEL until () is supplied so that the EL cell OEL maintains light emission.

In this case, the data voltage DATA has different multi-level values within a predetermined range in order to express gray scales. For example, when a voltage having a magnitude of 0 to 5 [V] can be output from a data driver supplying the data voltage DATA, in order to express an 8-bit gray scale (that is, 256 gray scale), The data voltage DATA may be divided at intervals of 20 [mV] (= 5 V / 256).

Referring to FIG. 3, when the data high voltage DATA high is 0 [V], one gray scale, that is, black, may be displayed, and the data high voltage DATA high and the data low voltage DATA low may be displayed. Depending on the difference, you can display 2 to 256 gradations.

However, even when the driving TFT T2 is turned off by applying the data high voltage DATA high due to its characteristic, the driving TFT T2 has a constant off current for the EL cell OEL. Will flow.

In this manner, even when the driving TFT T2 is turned off, the EL cell OEL emits light at a constant level due to the off current flowing through the EL cell OEL. Therefore, pure black cannot be displayed. do. In addition, since the EL cell OEL displays black having a constant level even when the driving TFT T2 is turned off in this manner, the brightness contrast of white to the brightness of black (hereinafter referred to as 'black brightness') As the contrast ratio is considerably lowered, the image appears to be discolored, resulting in a decrease in the overall image quality of the display device.

In order to solve this problem, it is important to reduce the black luminance to zero as much as possible, and minimize the current (off current) flowing through the driving TFT T2 when the driving TFT T2 is turned off. However, when the size of the data voltage DATA is increased in order to minimize the off current of the driving TFT T2, the output voltage of the data driver supplying the data voltage DATA and the size of internal devices must also be increased. Therefore, there is a problem in that the manufacturing cost of the data driver increases.

An object of the present invention for solving the above problems is to provide an apparatus capable of reducing the black luminance without changing the magnitude of the data voltage output from the data driver.

In order to achieve the above object, a black luminance control device using a voltage booster according to the present invention includes a booster voltage storage unit formed at an input terminal of a data line and storing a predetermined booster voltage, and orthogonal to the data line and the data line. And a sub-pixel connected to a gate line to form light corresponding to a predetermined gray level according to the sum of the data voltage applied to the data line and the booster voltage.

Further, the subpixel includes photoforming means for forming the light, and a driving TFT for driving the photoforming means, wherein the booster voltage shifts the data voltage in a direction in which the driving TFT is turned off. It is preferable.

In addition, a scan signal in which a first scan voltage for selecting the gate line and a second scan voltage having a logic value opposite to the first scan voltage are sequentially applied to the gate line is applied to the gate line. A data signal in which a first data voltage synchronized with one scan voltage and a second data voltage having a logic value opposite to the first data voltage are sequentially applied is applied, and the booster voltage and the first data voltage are added together. Is preferably equal to or greater than a turn-on voltage for turning on the driving TFT.

In addition, the predetermined booster voltage may be stored in the booster voltage storage unit at the beginning of a scan period to which the first scan voltage is applied.

In addition, the booster voltage storage unit may be formed of a capacitor.

The apparatus may further include a first switch unit connected to one end of the booster voltage storage unit to switch to supply a first voltage, and a second switch unit connected to the other end of the booster voltage storage unit to switch to supply a second voltage. Preferably, the predetermined booster voltage corresponds to a difference between the first voltage and the second voltage.

In addition, the first switch unit and the second switch unit may be formed of a MOSFET.

The luminance adjusting device may further include a first input terminal connected to the data line, a second input terminal connected to the gate line, and an output terminal connected to the gate terminal of each of the first switch unit and the second switch unit. It may further include a connected exclusive-NOR logic gate.

In addition, the display device according to the present invention for achieving the above object, the scan signal in which the first scan voltage for selecting the gate line and the second scan voltage having a logic value opposite to the first scan voltage is sequentially arranged A data signal formed to be orthogonal to the gate line to be applied and having a first data voltage synchronized with the first scan voltage and a second data voltage having a logic value opposite to that of the first data voltage; A booster voltage storage unit formed at an input terminal of the data line and a predetermined booster voltage is stored, and connected to the data line and the gate line, respectively, according to the data voltage and the booster voltage. And sub-pixels forming light corresponding to the gray level.

According to the present invention, when the driving TFT for driving one pixel is turned off in the display device, the image quality can be improved by reducing the black luminance by adjusting the magnitude of the voltage applied to the pixel.

In addition, according to the present invention, there is an advantage in that the black luminance can be efficiently reduced by connecting a voltage booster to the data line formed in the panel without increasing the range of the data voltage output from the data driver.

4 is a block diagram of a display apparatus according to a first embodiment of the present invention. 5 is a driving waveform diagram of the display device according to the first embodiment of the present invention.

As shown in FIG. 4, the display apparatus 400 according to the first exemplary embodiment of the present invention includes a gate line GL and a data line DL formed on a panel, and the gate line GL and a data line. A subpixel 410 arranged in a region defined by the intersection of the DL, a voltage booster unit 420 for providing a predetermined booster voltage to the subpixel 410, and the subpixel 410. ) Includes a gate driver 430 providing a scan voltage SCAN, and a data driver 440 providing a data voltage to the subpixel 410 in synchronization with the scan voltage.

When the scan voltage SCAN is supplied to the gate line GL, the sub pixel 410 receives the data voltage DATA from the data line DL and emits light with light corresponding to the data voltage DATA. Is displayed.

To this end, the subpixel 410 is a cell driver 411 connected to a gate line GL, a data line DL, a supply voltage source VDD, and connected to an anode electrode of an EL cell OEL, and the cell driver. An EL cell OEL is connected between the 411 and the ground voltage source GND. The cell driver 411 includes a switching TFT T1, a driving TFT T2, and a storage capacitor Cst.

The voltage booster unit 420 is connected between the data driver 440 and the sub pixel 410, and generates a predetermined booster voltage, and the generated booster voltage is output from the data driver 440. It is controlled to be applied to the sub pixel 410 together.

In detail, the voltage booster 420 includes a booster capacitor 421 connected to an input terminal of the data line DL, a first switch unit 422 for applying a predetermined booster voltage to the booster capacitor 421, and A second switch unit 423 is included.

The booster capacitor 410 is connected to an input terminal of the data line DL formed on the panel and may store a predetermined booster voltage. That is, the booster capacitor 410 is located in an area adjacent to the output terminal of the data driver 440 that supplies the data voltage DATA to the data line DL, and is electrically connected in series with the data line DL. It is formed to be.

The first switch unit 422 is connected to one end of the booster capacitor 421 to apply a first voltage V1 to one end of the booster capacitor 421 under control of the first switching control signal S1. do. The first switch unit 422 may be formed of a thin film transistor (TFT). When the first switching control signal S1 is applied to a gate terminal of the TFT, the first switch 422 transfers the first voltage V1 to the booster capacitor 421. It can be applied at one end of.

The second switch unit 423 is connected to the other end of the booster capacitor 421, and applies a second voltage V2 to the other end of the booster capacitor 421 by controlling the second switching control signal S2. do. The second switch unit 423 may also be formed of a thin film transistor (TFT). When the second switching control signal S2 is applied to a gate terminal of the TFT, the second switch 423 converts the second voltage V2 into the booster capacitor 421. Can be applied to the other end of

In FIG. 4, an example in which the display device 400 according to the present invention is implemented as a P-type organic electroluminescent display is described. In particular, an N-type substrate is used and the switching TFT is used. The T1 and the driving TFT T2 are formed of a P-type metal oxide semiconductor (MOSFET) in which carriers are holes.

However, the display apparatus 400 uses a P-type substrate, and the switching TFT T1 and the driving TFT T2 are formed of an N-type metal oxide semiconductor (MOSFET) whose carrier is electrons. Can be.

In addition, in FIG. 4, the display device 400 uses the EL cell OEL that emits light in accordance with the data voltage DATA as a means for forming light in the sub-pixel 410.

However, the display device 400 forms light according to the driving TFT T2 for driving the subpixel 410 and the data voltage DATA by the data voltage DATA applied to the data line DL. It may include any type of display device including the light forming means. Therefore, the EL cell OEL is merely an example of a light forming means, and the light forming means emits itself by the data voltage DATA applied to the data line DL or by a backlight. By transmitting or reflecting the irradiated light, it can include any type of element that forms light corresponding to a predetermined gray scale.

Hereinafter, an operation of the display apparatus 400 according to the first embodiment of the present invention will be described with reference to FIGS. 4 and 5.

First, the gate driver 430 supplies a scan voltage SCAN to the sub pixel 410 through a gate line GL to emit light of the sub pixel 410 formed in the display device 400. In the scan voltage SCAN, a scan low voltage SCAN low for selecting a gate line GL to be scanned and a scan high voltage SCAN high having a logic value opposite to the scan low voltage are sequentially arranged. In FIG. 5, the scan high voltage SCAN high is greater than the scan low voltage SCAN low so as to drive a P-type organic light emitting display.

Of the scan voltages SCAN having such a shape, when the scan low voltage SCAN low is first supplied to the gate line GL, the switching TFT T1 in the subpixel 410 is turned on. .

In particular, the voltage booster unit 420 according to the present invention includes a booster capacitor 420 at an initial stage of a scan period in which the scan low voltage SCAN low is supplied to the gate line GL, that is, a gate turn-on time. Stores a predetermined booster voltage. Here, a period during which a predetermined booster voltage is applied to the booster capacitor 420 during the scan period is defined as a booster voltage application period.

To this end, the first switching control signal S1 is applied to the first switch unit 422 during the initial booster voltage application period during the scan period, thereby applying the first voltage V1 to one end of the booster capacitor 420. do.

In addition, the second switching control signal S2 is applied to the second switch unit 423 in the same period as the first voltage is applied, so that the second voltage V2 is applied to the other end of the booster capacitor 420. do.

Accordingly, at the beginning of the scan period, the booster capacitor 420 stores the booster voltages V1-V2 corresponding to the difference between the first voltage V1 and the second voltage V1.

In particular, as shown in FIG. 4, when the display device 400 is a P-type organic electroluminescent display, different gray levels of black or more are displayed according to the magnitude of the data low voltage, and the data high voltage ( DATA high) displays black. Therefore, in the P-type organic light emitting display device, the booster voltages V1-V2 are driven in the direction in which the driving TFT T2 is turned off, that is, the data high voltage DATA. It is preferable to set such that it has a value shifted from the high to the data low direction. For example, the first voltage V1 may be set to be greater than the second voltage V2 (that is, V1-V2> 0). Accordingly, the sum of the data high voltage DATA high and the booster voltages V1-V2 may display a lower black color. On the other hand, when the display device 400 is formed of an N type organic electroluminescent display, the first voltage V1 is set to be smaller than the second voltage V2 (that is, V1-V2 <0). ), The black luminance may be reduced by using the sum of the data voltage and the booster voltages V1-V2.

As described above, when the booster voltages V1 to V2 are stored in the booster capacitor 420, the data driver 440 may subsequently store the subpixels through the data line DL in the period after the booster voltage application period. The data low voltage DATA low for displaying a specific gray level of black or more is supplied to 410. Here, a period during which the data voltage DATA low is applied to the sub pixel 410 during the scan period is defined as a data voltage application period.

Then, when the scan low voltage SCAN low is supplied to the gate line GL, the switching TFT T1 in the sub pixel 410 is in a turn-on state, and thus the booster voltage V1 is applied. The sum of -V2) and the data low voltage DATA low is supplied to the node N. That is, the data voltage DATA which is increased by the booster voltages V1-V2 is supplied to the node N.

Then, the sum of the booster voltages V1-V2 and the data low voltage DATA low supplied to the node N is charged to the storage capacitor Cst and supplied to the gate terminal of the driving TFT T2. The driving TFT T2 is the amount of current I supplied from the supply voltage source VDD to the EL cell OEL in response to the sum of the booster voltages V1-V2 and the data low voltage DATA low supplied to the gate terminal. ), The amount of light emitted by the EL cell OEL is adjusted.

In addition, even when the switching TFT T1 is turned off, the booster voltages V1-V2 and the data low voltage DATA low charged in the storage capacitor Cst are discharged, and thus the driving TFT T1 is moved to the next frame. The current I from the supply voltage source VDD is supplied to the EL cell OEL until the data signal DATA is supplied so that the EL cell OEL maintains light emission.

As described above, in the present invention, the booster voltages V1-V2 are supplied to the subpixels 410, thereby driving the data low voltage DATA low corresponding to the turn-on voltage of the driving TFT T2 and the driving. The data high voltage DATA high corresponding to the turn-off voltage of the TFT T2 is increased by the booster voltages V1-V2.

As a result, according to the present invention, when the driving TFT T2 is turned on and turned off, the magnitude of the data voltage DATA supplied to the subpixel 410 is increased by the magnitude of the booster voltages V1-V2. As the size of the data voltage DATA decreases, the amount of the current I flowing in the EL cell OEL is also reduced, thereby reducing the luminance of light emitted by the sub-pixel 410. . As described above, as the luminance of light emitted by the subpixel 410 decreases, the black luminance displayed by the subpixel 410 may also decrease. However, according to the present invention, since the gray level of the light emitted by the sub pixel 410 is reduced regardless of the gray level to be displayed by the sub pixel 410, the white brightness corresponding to the white brightness is reduced. It will also decrease. However, in general, the brightness of white in the display device is easier to adjust than the black brightness, and the effect on the image quality of the entire image is also lower than that of the black brightness.

Accordingly, in the present invention, the black luminance of the image can be reduced by simply supplying a booster voltage to the data line DL without modifying the data driver 440, thereby reducing the overall image quality of the image including the contrast ratio. There is an advantage that can be improved.

6 is a block diagram of a display apparatus according to a second embodiment of the present invention.

Referring to FIG. 6, the display device 600 according to the second exemplary embodiment of the present invention includes a sub pixel 410 arranged in an area defined by the intersection of a gate line GL and a data line DL, and the sub pixel 410. A voltage booster unit 420 for providing a predetermined boost voltage to the pixel 410, a gate driver 430 for providing a scan voltage SCAN to the subpixel 410, and The data driver 440 provides a data voltage to the subpixel 410 in synchronization with a scan voltage.

In particular, the voltage booster 420 uses the data voltage DATA applied to the data line DL and the scan voltage SCAN applied to the gate line GL. The logic gate 424 is further formed to generate two switching control signals S1.

Herein, the configuration and operation of the subpixel 410, the gate driver 430, and the data driver 440, and the driving waveform applied to the display device 600 are the same as those described in the first embodiment of the present invention. Since it is the same, overlapping description is omitted. Therefore, the configuration and operation of the display apparatus 600 according to the second embodiment of the present invention will be described below with reference to the voltage booster unit 420.

When the data voltage DATA and the scan voltage SCAN have different logic values, the logic gate 424 may turn on the first switch unit 422 and the second switch unit 423 at the same time. low) Output a logic value. In contrast, the logic gate 424 may simultaneously turn off the first switch unit 422 and the second switch unit 423 when the data voltage DATA and the scan voltage SCAN have the same logic value. Outputs a high logic value so that

To this end, when the first switch unit 422 and the second switch unit 423 are each formed of a P-type MOSFET, the logic gate 424 is formed of an exclusive-NOR logic gate. One input terminal 424-1 of the two input terminals is connected to the data line DL, and the other input terminal 424-2 is connected to the gate line GL. The output terminal 424-3 of the logic gate 424 is connected to the gate terminal of the first switch unit 422 and the gate terminal of the second switch unit 423.

Accordingly, a high logic data high voltage DATA high is input from the data line DL to the logic gate 424 during a booster voltage application period during the scan period, and a low logic from the gate line GL. The scan low voltage (SCAN low) is input. Accordingly, the logic gate 424 may output a low logic value during the booster voltage application period, thereby turning on the first switch unit 422 and the second switch unit 423, thereby boosting the capacitor 421. The booster voltages V1-V2 may be applied to the boosters.

On the other hand, during the data voltage application period during the scan period, a low logic data low voltage DATA low is input from the data line DL to the logic gate 424, and also low logic from the gate line GL. Scan low voltage (SCAN low) is input. Accordingly, the logic gate 424 may output a high logic value during the data voltage application period, thereby turning off the first switch unit 422 and the second switch unit 423, thereby boosting the capacitor 421. ), The booster voltages V1-V2 are no longer applied.

The voltage booster unit according to the present invention can be applied to not only an organic light emitting display device but also various types of display devices for adjusting the brightness of a subpixel using a data voltage. In addition, although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above embodiment is for the purpose of description and not for the limitation thereof. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a diagram illustrating a light emission principle of a conventional organic light emitting display device.

FIG. 2 is an equivalent circuit diagram of subpixels of a general P-type organic electroluminescent display. FIG.

3 is a driving waveform diagram of a general type organic light emitting display device;

4 is a configuration diagram of a display device according to a first embodiment of the present invention.

5 is a driving waveform diagram of a display device according to a first embodiment of the present invention;

6 is a configuration diagram of a display device according to a second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

400: display device 410: subpixel

411: cell driver 420: voltage booster

421: booster capacitor 422: first switch unit

423: second switch unit 424: logic gate

424-1, 424-2: input terminal 424-3: output terminal

430: gate driver 440: data driver

600: display device

Claims (16)

A booster voltage storage unit formed at an input terminal of the data line to store a predetermined booster voltage; And And a sub pixel connected to the data line and the gate line orthogonal to the data line, and configured to form light corresponding to a predetermined gray scale according to a sum of the data voltage and the booster voltage applied to the data line. Black luminance control device using a voltage booster. The method of claim 1, The sub-pixel includes light forming means for forming the light, and a driving TFT for driving the light forming means, And the booster voltage shifts the data voltage in a direction in which the driving TFT is turned off. The method of claim 1, A scan signal in which a first scan voltage for selecting the gate line and a second scan voltage having a logic opposite to the first scan voltage are sequentially applied to the gate line is applied to the gate line, The data line is supplied with a data signal in which a first data voltage synchronized with the first scan voltage and a second data voltage having a logic value opposite to the first data voltage are sequentially arranged. And a sum value of the booster voltage and the first data voltage is equal to or greater than a turn-on voltage for turning on the driving TFT. The method of claim 1, And the predetermined booster voltage is stored in the booster voltage storage unit at an initial stage of a scan period to which the first scan voltage is applied. The method of claim 1, And the booster voltage storage part is formed of a capacitor. The method of claim 1, A first switch unit connected to one end of the booster voltage storage unit to switch to supply a first voltage; And A second switch unit connected to the other end of the booster voltage storage unit to switch to supply a second voltage; And the predetermined booster voltage corresponds to a difference between the first voltage and the second voltage. The method of claim 6, The black brightness control device using a voltage booster, characterized in that the first switch unit and the second switch unit is formed of a MOSFET. The method of claim 7, wherein Exclusive-NOR logic gate connected to a first input terminal connected to the data line, a second input terminal connected to the gate line, and an output terminal connected to a gate terminal of each of the first switch unit and the second switch unit. Black luminance control device using a voltage booster, characterized in that it further comprises. A gate line to which a scan signal in which a first scan voltage for selecting a gate line and a second scan voltage having a logic value opposite to the first scan voltage are sequentially arranged is applied; A data line formed to be orthogonal to the gate line and to which a data signal sequentially arranged with a first data voltage synchronized with the first scan voltage and a second data voltage having a logic value opposite to the first data voltage is applied; A booster voltage storage unit formed at an input terminal of the data line to store a predetermined booster voltage; And And a subpixel connected to the data line and the gate line, respectively, to form light corresponding to a predetermined gray level according to the data voltage and the booster voltage. The method of claim 9, The sub-pixel includes light forming means for forming the light, and a driving TFT for driving the light forming means, And the booster voltage shifts the data voltage in a direction in which the driving TFT is turned off. The method of claim 9, And a sum value of the booster voltage and the first data voltage is equal to or greater than a turn-on voltage for turning on the driving TFT. The method of claim 9, And the predetermined booster voltage is stored in the booster voltage storage unit at the beginning of a scan period to which the first scan voltage is applied. The method of claim 9, And the booster voltage storage part is formed of a capacitor. The method of claim 9, A first switch unit connected to one end of the booster voltage storage unit to switch to supply a first voltage; And A second switch unit connected to the other end of the booster voltage storage unit to switch to supply a second voltage; And the predetermined booster voltage corresponds to a difference between the first voltage and the second voltage. The method of claim 14, And the first switch unit and the second switch unit are formed of MOSFETs. The method of claim 15, Exclusive-NOR logic gate connected to a first input terminal connected to the data line, a second input terminal connected to the gate line, and an output terminal connected to a gate terminal of each of the first switch unit and the second switch unit. Display device further comprises.

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