KR20160085059A - Fast Response Liquid Crystal Display - Google Patents

Abstract

The present invention relates to a liquid crystal display device with high-speed response property. While liquid crystal molecules are temporally vertically aligned, a voltage higher than the pixel voltage of a gray level is firstly applied. And, a data voltage corresponding to the gray level is applied again. Thereby, the alignment speed of liquid crystal can be controlled. The liquid crystal display device includes a first substrate and a second substrate which face each other; an insulating layer formed on the first substrate; a first electrode and a second electrode which are overlapped with each other by interposing the insulating layer; a third electrode which is formed on the second substrate; and a liquid crystal layer which is injected between the first substrate and the second substrate and consists of liquid crystal molecules.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device having a high-

More particularly, the present invention relates to a liquid crystal display device in which liquid crystal molecules are temporarily vertically arranged, a voltage higher than a pixel voltage of a gradation level to be displayed is applied first, and a data voltage corresponding to the gradation level is applied again, To a liquid crystal display device having a high-speed response characteristic capable of controlling an arrangement speed of a liquid crystal display device.

An in-plane switching (IPS) mode and a fringe-field switching (FFS) mode, which are horizontally aligned liquid crystal displays that can realize a wide viewing angle, have been developed.

In the IPS mode, the pixel electrode and the common electrode are formed on the same plane so that the direction of the electric field has a horizontal electric field parallel to the substrate. The IPS mode rotates the liquid crystal molecules in a plane parallel to the substrate, thereby realizing a wide viewing angle.

The FFS mode is a kind of the IPS mode and is the same in terms of arranging the liquid crystal using the horizontal electric field.

However, in the FFS mode, the pixel electrode and the common electrode are formed in different layers, and the liquid crystal molecules are arranged using a horizontal electric field and a vertical electric field.

Since the FFS mode arranges the liquid crystal molecules on the pixel electrode, the FFS mode has better characteristics than the IPS mode in terms of transmittance.

In addition, most of the liquid crystal molecules are rotated in a plane parallel to the substrate in the same manner as the IPS mode in terms of the viewing angle, and thus the liquid crystal molecules are equivalent to the IPS mode.

In such a horizontal switching liquid crystal mode, since it is mainly influenced by a relatively small elastic constant K ₂₂ than other elastic constants, it is not fast enough to be used in a display device which realizes fast moving images.

Accordingly, as the performance of a liquid crystal display device develops, a demand for a faster response speed is increasing.

Korean Patent Publication No. 10-2014-0024603 Korean Patent Publication No. 10-2014-0001044 Korean Patent Publication No. 10-2010-0071185

Disclosure of Invention Technical Problem [8] The present invention provides a driving method for improving the response speed of a liquid crystal and a liquid crystal display device having the driving method for solving the problem of the conventional liquid crystal display.

The liquid crystal molecules are temporarily vertically aligned, and a voltage higher than the pixel voltage of the gradation level to be displayed is applied first, and a data voltage corresponding to the gradation level is applied to control the arrangement speed of the liquid crystal And it is an object of the present invention to provide a liquid crystal display device having a high-speed response characteristic.

The present invention provides a plasma display panel comprising a first substrate and a second substrate facing each other, and an insulating film formed on the first substrate, wherein the first electrode and the second electrode overlap each other with the insulating film interposed therebetween and are formed on the second substrate And a liquid crystal display device having a high-speed response characteristic including a third electrode and a liquid crystal layer.

The liquid crystal molecules are temporarily vertically aligned by applying a vertical voltage to the first and third electrodes, and a voltage higher than the pixel voltage of the gradation level to be displayed on the first and second electrodes is applied for a short time And a data voltage corresponding to a gradation level to be displayed again, thereby controlling the alignment speed of the liquid crystal.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a liquid crystal display device including a first substrate and a second substrate facing each other, an insulating film formed on the first substrate, And a liquid crystal layer formed between the first substrate and the second substrate, the liquid crystal layer being made of a plurality of liquid crystal molecules .

Here, the first electrode and the third electrode are plate-shaped, and the second electrode is a grid-shaped electrode extending in a predetermined direction.

And a width and an interval of the second electrode are smaller than 10 mu m.

The liquid crystal molecules have a positive dielectric anisotropy and liquid crystal molecules between the first substrate and the second substrate are arranged in parallel with the surface of the substrate when no electric field is applied to the liquid crystal layer.

And a second polarizer attached to the outside of the second substrate, wherein the first polarizer is attached to the outside of the first substrate, and the second polarizer is attached to the outside of the second substrate when the electric field is not applied to the liquid crystal layer And the long axis of one liquid crystal molecule is arranged in parallel with the polarization axis of the first polarizing plate or the second polarizing plate.

And a direction of a long axis of the liquid crystal molecules arranged in parallel with the surface of the first substrate is formed at a predetermined angle with the second electrode.

And the liquid crystal display device displays black when no electric field is applied.

A common voltage is applied to the first electrode, a data voltage is applied to the second electrode to form a horizontal electric field, and a common voltage is applied to the first and third electrodes to form a vertical electric field. do.

And the first electrode and the third predetermined period of time a pulse voltage of a predetermined size between the electrodes T ₁ is applied, and wherein the constant voltage higher than the voltage corresponding to the gradation to be displayed to the second electrode hours T ₂ (T ₂ < T ₁ ) And applies a data voltage corresponding to the gray level again.

And driving is performed through timing control of a pulse voltage having a predetermined magnitude between the first electrode and the third electrode and a voltage applied between the first electrode and the second electrode.

In order to control the timing of a pulse voltage having a constant magnitude between the first and third electrodes and a voltage applied between the first electrode and the second electrode, a plurality of thin film transistors in the pixel are connected to different data lines And a gate terminal of the thin film transistor is superimposed on the gate line between adjacent pixels.

A liquid crystal display device having a high-speed response characteristic according to the present invention for achieving another object comprises a first substrate and a second substrate facing each other, an insulating film formed on the first substrate, and a second substrate overlapping each other with the insulating film interposed therebetween A liquid crystal layer sandwiched between the first and second substrates; a liquid crystal display panel including a first electrode and a second electrode formed on the first substrate, a third electrode formed on the second substrate, and a liquid crystal layer injected between the first substrate and the second substrate; A data driver for applying a data voltage for driving the liquid crystal display panel, a gate driver for applying a gate signal for driving the liquid crystal display panel, a first or second common voltage Vcom1, A common electrode driver for generating and applying a common voltage pulse having a level of Vcom2 and a pulse voltage of a constant magnitude between the first electrode and the third electrode, It characterized in that it comprises a; timing control for the timing control of voltage to be applied between the electrode and the second electrode.

Here, the voltage generator generates a reference gradation voltage (Vref) for generating a pixel voltage and a voltage (Vh) higher than the gradation voltage and provides the gradation voltage to the data driver. The gate voltage (Von) And provides the gate driver to the gate driver.

The voltage generating unit generates a first common voltage Vcom1 applied to the first electrode formed on the first substrate and a second common voltage Vcom2 applied to the third electrode formed on the second substrate, To the user.

The data driver applies a data voltage to the first data lines D1L1 to D1Ln by using a voltage Vh higher than the gradation voltage under the control of the timing controller and uses the reference gradation voltage Vref The image data DATA is converted into an analog data voltage and applied to the second data lines D2L1 to D2Ln.

The common electrode driver is electrically connected to a third electrode formed on the second substrate, and has a first or second common voltage (Vcom1, Vcom2) level provided from the voltage generator under the control of the timing controller And a common voltage pulse is generated and provided to the third electrode.

The liquid crystal display device having the high-speed response characteristics according to the present invention has the following effects.

First, a liquid crystal display device having a high-speed response characteristic can be realized.

Secondly, the liquid crystal molecules can be controlled by arranging the liquid crystal molecules temporarily vertically, applying a voltage higher than the pixel voltage of the gradation level to be displayed first, and applying a data voltage corresponding to the gradation level again.

Third, a driving method for controlling the alignment speed of the liquid crystal applicable to a display device implementing a moving image with a fast response time is provided.

1 is a schematic diagram of a liquid crystal display device according to an embodiment of the present invention
2 is a cross-sectional view of a liquid crystal display according to an embodiment of the present invention.
3 is a block diagram showing the concept of a driving method of a liquid crystal display device according to the present invention
4 is a graph showing a waveform of a voltage applied for driving a liquid crystal display according to the present invention
5 is a graph showing turn-on and turn-off times between black and white of a conventional FFS liquid crystal cell
6 is a graph showing the turn-on and turn-off times between black and white of the liquid crystal display according to the present invention
Fig. 7 shows an example of the response time between gradations. It is a graph showing the response characteristics between gradations of 50% -100% of the maximum transmittance of the FFS liquid crystal cell of the related art
8 is a graph showing response characteristics between gradations between 50% and 100% of the maximum transmittance of the liquid crystal display according to the present invention,

Hereinafter, a preferred embodiment of a liquid crystal display device having a high-speed response characteristic according to the present invention will be described in detail.

The features and advantages of the liquid crystal display device having the high-speed response characteristics according to the present invention will be apparent from the following detailed description of each embodiment.

FIG. 1 is a configuration diagram of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

The liquid crystal molecules are temporarily vertically aligned, a voltage higher than the pixel voltage of the gradation level to be displayed is applied first, and a data voltage corresponding to the gradation level is applied to control the alignment speed of the liquid crystal The present invention can be applied to a display device that implements moving images with fast response times.

To this end, a liquid crystal display according to an embodiment of the present invention includes a first electrode arranged on a first substrate on which a plurality of gate lines and data lines intersecting each other is formed, a plurality of slit patterns arranged on the first electrode, And a liquid crystal layer interposed between the display substrate and the counter substrate. The counter substrate includes a counter substrate including a first substrate,

And a second common voltage pulse is applied to the third electrode during a first predetermined period every time the frame is started in the common electrode driver.

In the previously filed display panel and the display device having the same (Application No. 10-2008-0129815), the common electrode driver applies a second common voltage pulse to the third electrode during a first predetermined interval every time the frame starts After that, the data driver applies the data voltage to the pixel electrode at the reference gradation voltage Vref after the first period.

However, when such a driving technique is used, the response speed is faster than the previous FFS mode, but the turn-on time and the response time between gradations still need to be improved.

On the other hand, according to the driving method of the present invention, after applying the second common voltage pulse, different voltages are applied to different first and second data lines rather than applying a data voltage to one data line .

The data driver applies a voltage (Vh) higher than the reference gradation voltage (Vref) to the first data lines (D1L1 to D1Ln) during a second period which is shorter than the first period in the first period, A data voltage is applied to the second data lines D2L1 to D2Ln to the reference gradation voltage Vref.

Then, the gate driving unit sequentially applies gate signals for sequentially activating the gate lines GL1 to GLm using the third control signal supplied from the timing control unit and the gate ON and OFF voltages Von and Voff supplied from the voltage generating unit .

The gate signals are applied to the gate lines GL1 to GLm.

1, a liquid crystal display device having a high-speed response characteristic according to the present invention includes a liquid crystal display panel 200, a timing controller 400, a voltage generator 500, a data driver 600, A common electrode driving unit 800, and a light source driving circuit unit 440.

The voltage generator 500 generates driving voltages for driving the liquid crystal display panel 200.

For example, the voltage generator 500 generates a reference gradation voltage Vref for generating a pixel voltage and a voltage Vh higher than the gradation voltage and provides the generated voltage to the data driver 600. The gate voltage Von And a gate-off voltage Voff to the gate driver 700.

The voltage generator 500 generates the first common voltage Vcom1 applied to the first electrode formed on the first substrate 131 and the second common voltage Vcom1 applied to the third electrode 122 formed on the second substrate 130 2 common voltage Vcom2.

The voltage generator 500 provides the first and second common voltages Vcom1 and Vcom2 to the common electrode driver 800. [

The data driver 600 receives the second control signal 420 and the image data DATA from the timing controller 400 and receives the reference gray-scale voltage Vref and the gray- And receives a high voltage Vh.

The data driver 600 applies a voltage Vh higher than the gray scale voltage to the first data lines D1L1 to D1Ln.

The image data DATA is converted into an analog data voltage using the reference gradation voltage Vref and applied to the second data lines D2L1 to D2Ln.

The gate driver 700 may be controlled by the third control signal 430 supplied from the timing controller 400 and the gate on and off voltages Von and Voff supplied from the voltage generator 500, And generates gate signals sequentially activating the gate lines GL1 to GLm.

The gate signals are applied to the gate lines GL1 to GLm.

The common electrode driver 800 is electrically connected to a third electrode 122 formed on the second substrate 130. The common electrode driver 800 applies the first or second common voltage Vcom1 or Vcom2 supplied from the voltage generator 500 in response to the first control signal 410 provided from the timing controller 400, Level and provides it to the third electrode.

The common electrode driver 800 may block the common voltage pulse applied to the third electrode 122 such that the third electrode 122 is electrically floated while the data voltage Vref is applied.

The light source driving circuit unit 900 may include a backlight 300 in response to the fourth control signal 440 provided from the timing controller 400 while a voltage is applied to the third electrode 122. [ Can be controlled.

The liquid crystal display device according to the present invention has a first substrate 131 and a second substrate 130 facing each other, a first electrode 121 formed on the first substrate 131, An insulating layer 150 between the first electrode 121 and the second electrode 120 and a second electrode 120 formed under the second substrate 130. The second electrode 120 may be formed in a pattern shape The second electrode 120 is formed in a grid shape having a predetermined width and a predetermined interval. The first electrode 121 and the third electrode 122 have a plate shape.

The liquid crystal layer 141 includes a plurality of liquid crystal molecules 140 between the first substrate 131 and the second substrate 130.

The width and the interval of the second electrode 120 are smaller than 10 mu m.

The liquid crystal molecules 140 have positive dielectric anisotropy and the liquid crystal molecules 140 of the liquid crystal layer 141 between the first substrate 131 and the second substrate 130 are separated from the first and second substrates 130, And are arranged in parallel with the surface.

The liquid crystal display panel may further include a first polarizing plate disposed adjacent to the first substrate 131 and having a first polarization axis and a second polarizing plate disposed adjacent to the second substrate and having a second polarization axis.

Wherein the liquid crystal display panel has the same rubbing direction as the first or second polarization axes, the liquid crystal display panel displays black in an electric field not applied, and the rubbing direction is from 0 to 45 And can have angles up to degrees.

A common voltage is applied between the first electrode 121 and the third electrode 122 to display the liquid crystal molecules on the first electrode 121 and the second electrode 120 in a state where the liquid crystal molecules are temporarily vertically aligned. A voltage higher than the pixel voltage of the gradation level is applied for a short time, and the gradation data voltage of the gradation to be displayed is applied to the first electrode 121 and the second electrode 120 to display the gradation.

The liquid crystal display device having the high-speed response characteristics according to the present invention will now be described in detail with reference to FIG.

2, the liquid crystal display panel 200 includes a first substrate 131 and a second substrate 130 facing each other, and a liquid crystal layer 130 disposed between the first substrate 131 and the second substrate 130. [ (140).

The first electrode 121 has a plate shape and an insulating layer 150 is formed on the first electrode 121. A second electrode 120 is formed on the insulating layer 150. The first electrode 121 has a constant width .

A first polarizing plate 11 is positioned outside the first substrate 131 and a second polarizing plate 22 is positioned outside the second substrate 130.

The polarization axes of the first polarizing plate 11 and the second polarizing plate 22 may be orthogonal to each other.

A plurality of liquid crystal molecules adjacent to the first substrate 131 and the second substrate 130 are arranged in parallel with the first substrate 131, The liquid crystal molecules are initially oriented in a constant direction parallel to the substrate in a state where no electric field is applied to the liquid crystal molecules 140.

The liquid crystal molecules may have positive dielectric anisotropy and the direction in which the liquid crystal molecules are aligned in parallel with the initial substrate may be parallel to the polarization axis of any one of the first polarizing plate 11 and the second polarizing plate 22, 11 and the second polarizing plate 22, and displays black in a state in which no electric field is applied.

Although not shown, a color filter is formed on the first substrate 131 or the second substrate 130.

Each color filter can display one of three primary colors of red, green, and blue, or primary colors such as yellow, cyan, magenta, and the like. In addition, each pixel can display a mixed color or a white color of the basic color in addition to the basic color.

2 shows an OFF state in which no electric field is applied.

Referring to FIG. 2, liquid crystal molecules adjacent to the first substrate 131 are aligned with the second electrode 120 at a predetermined angle. The direction in which the liquid crystal molecules are initially oriented may be parallel to the polarization axis of either one of the first polarizing plate 11 and the second polarizing plate 22 and the direction of the other one of the first polarizing plate 11 and the second polarizing plate 22 And may be orthogonal to the polarization axis.

Accordingly, the light incident on the first substrate 131 is not transmitted through the first polarizing plate 11, the liquid crystal layer 141, and the second polarizing plate 22, and thus displays a black state.

A driving method of a liquid crystal display device having such a high-speed response characteristic according to the present invention will now be described.

FIG. 3 is a block diagram showing the concept of a driving method of a liquid crystal display according to the present invention, and FIG. 4 is a graph showing a waveform of a voltage applied for driving a liquid crystal display according to the present invention.

A voltage is applied between the first electrode 121 and the third electrode 122 for a short period of time before the liquid crystal display panel is turned on to form a vertical electric field.

The liquid crystal molecules are temporarily vertically aligned.

In this manner, a voltage (a voltage corresponding to the gray scale to be displayed for a short period of time) between the first electrode 121 and the second electrode 120 before being in a gray state or a white state in the vertically aligned state And a voltage Vf corresponding to the voltage to be displayed is applied to the first electrode 121 and the second electrode 120 so as to be in a gray state or white ) State.

A voltage Vp is applied between the first electrode 121 and the third electrode 122 again to switch the vertical electric field to the other gradation state Vf to be displayed, And the liquid crystal molecules are vertically aligned.

A voltage Vh higher than the voltage Vf corresponding to the gradation to be displayed is applied between the first electrode 121 and the second electrode 120 for a predetermined short time T1 and then a voltage corresponding to the gradation to be displayed (Vf) is applied to implement the gradation.

The turn-on and turn-off characteristics and the gradation response characteristics of the liquid crystal display device having the high-speed response characteristics according to the present invention will now be described.

FIG. 5 is a graph showing turn-on and turn-off times of a conventional FFS liquid crystal cell between black and white, and FIG. 6 is a graph illustrating turn-on and turn-off times of a black and white of a liquid crystal display according to the present invention.

7 shows an example of the inter-gradation response time, which is a graph showing the inter-gradation response characteristics between 50% and 100% of the maximum transmittance of the FFS liquid crystal cell of the related art. Fig. 8 shows an example of the inter- Is a graph showing a response characteristic between gradations of 50% -100% of the maximum transmittance of the liquid crystal display device according to the invention.

In the case of the conventional FFS mode in which the first electrode 121 and the second electrode 120 are formed on the first substrate 131 with the insulating film 150 interposed therebetween and the third electrode 122 is not formed The second electrode 120 overlaps the first substrate 131 with the insulating layer 150 interposed therebetween and the second substrate 130 is formed on the first substrate 131. In this case, The response time was measured. The results are shown in Tables 1 and 2.

Table 1 shows the measured response time results of the previous FFS cell.

Table 2 is a table showing the results of response time between gradations of a liquid crystal display device having a high-speed response characteristic according to the present invention.

In the case of the liquid crystal display according to the embodiment of the present invention showing the results of FIG. 6, FIG. 8, and Table 2 as compared with the conventional liquid crystal display device showing the results of FIG. 5, FIG. 7 and Table 1, And it was found.

In the case of the liquid crystal display device according to the embodiment of the present invention, it was found that a very short response time was exhibited in all gradation periods.

In the liquid crystal display device having the high-speed response characteristics according to the present invention as described above, a voltage higher than the pixel voltage of the gradation level to be displayed is first applied in a state in which the liquid crystal molecules are temporarily vertically arranged, The arrangement speed of the liquid crystal can be controlled by applying a voltage, so that the present invention can be applied to a display device implementing a moving image with a fast response time.

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

It is therefore to be understood that the specified embodiments are to be considered in an illustrative rather than a restrictive sense and that the scope of the invention is indicated by the appended claims rather than by the foregoing description and that all such differences falling within the scope of equivalents thereof are intended to be embraced therein It should be interpreted.

11, 22: polarizing plates 120, 121, 122: electrodes
130, 131: substrate 140: liquid crystal molecule
141: liquid crystal layer 150: insulating film
200: liquid crystal display panel 300: backlight
400: timing control unit 500: voltage generating unit
600: Data driver 700: Gate driver
800: common electrode driver 900: light source driver

Claims (16)

A first substrate and a second substrate facing each other;
An insulating film formed on the first substrate;
A first electrode and a second electrode overlapping each other with the insulating film interposed therebetween;
A third electrode formed on the second substrate;
And a liquid crystal layer injected between the first substrate and the second substrate and made of a plurality of liquid crystal molecules. The method of claim 1, wherein the first and third electrodes are in the form of a plate,
And the second electrode is a grid-shaped electrode extending in a predetermined direction. The liquid crystal display of claim 2, wherein a width and an interval of the second electrode are smaller than 10 mu m. The liquid crystal display device according to claim 1, wherein the liquid crystal molecules have positive dielectric anisotropy,
Wherein liquid crystal molecules between the first substrate and the second substrate are arranged in parallel with a surface of the substrate when an electric field is not applied to the liquid crystal layer. The liquid crystal display according to claim 1, further comprising: a first polarizer attached to the outside of the first substrate;
And a second polarizer attached to the outside of the second substrate,
And the long axis of the liquid crystal molecules arranged in parallel with the surface of the substrate is arranged in parallel with the polarization axis of the first polarizing plate or the second polarizing plate when no electric field is applied to the liquid crystal layer. . 6. The liquid crystal display of claim 5, wherein a direction of the long axis of the liquid crystal molecules arranged in parallel to the surface of the first substrate is a constant angle with the second electrode. The liquid crystal display device according to claim 5, wherein the liquid crystal display device displays black when no electric field is applied. The method of claim 1, further comprising: applying a common voltage to the first electrode, applying a data voltage to the second electrode to form a horizontal electric field, applying a common voltage to the first and third electrodes, Wherein the liquid crystal display device has a high-speed response characteristic. The plasma display apparatus according to claim 8, wherein a pulse voltage having a constant magnitude is applied between the first electrode and the third electrode for a predetermined time T ₁ , and a voltage higher than a voltage corresponding to the gray scale to be displayed is applied to the second electrode for a predetermined time T ₂ (T ₂ < T ₁ ) And applies a data voltage corresponding to the gray level again to the liquid crystal display device. The plasma display apparatus of claim 9, wherein driving is performed through timing control of a pulse voltage having a predetermined magnitude between the first electrode and the third electrode and a voltage applied between the first electrode and the second electrode. The liquid crystal display device comprising: The plasma display apparatus according to claim 9, wherein, for timing control of a pulse voltage having a constant magnitude between the first electrode and the third electrode and a voltage applied between the first electrode and the second electrode,
Wherein a plurality of thin film transistors in a pixel are connected to different data lines, and a gate terminal of the thin film transistor is superimposed on the gate line between adjacent pixels. A first substrate and a second substrate facing each other, an insulating film formed on the first substrate, a first electrode and a second electrode overlapping each other with the insulating film interposed therebetween, A liquid crystal display panel including three electrodes, and a liquid crystal layer injected between the first substrate and the second substrate;
A voltage generator for generating driving voltages for driving the liquid crystal display panel;
A data driver for applying a data voltage for driving the liquid crystal display panel;
A gate driver for applying a gate signal for driving the liquid crystal display panel;
A common electrode driver for generating and applying a common voltage pulse having a first or second common voltage (Vcom1, Vcom2) level;
And a timing controller for controlling the timing of a pulse voltage having a predetermined magnitude between the first electrode and the third electrode and a voltage applied between the first electrode and the second electrode. Liquid crystal display device. The display device according to claim 12, wherein the voltage generator generates and supplies a reference gradation voltage (Vref) for generating a pixel voltage and a voltage (Vh) higher than the gradation voltage to the data driver,
And a gate-on voltage Von and a gate-off voltage Voff are generated and provided to the gate driver. 13. The plasma display panel of claim 12, wherein the voltage generating unit generates a first common voltage (Vcom1) applied to a first electrode formed on a first substrate and a second common voltage (Vcom2) applied to a third electrode formed on a second substrate Wherein the common electrode driving unit supplies the common electrode driving unit with the common electrode driving unit. The data driver according to claim 12, wherein, under the control of the timing controller,
A data voltage is applied to the first data lines D1L1 to D1Ln using a voltage Vh higher than the gradation voltage,
And the image data (DATA) is converted into an analog data voltage using the reference gradation voltage (Vref) and applied to the second data lines (D2L1 to D2Ln). 13. The organic light emitting display as claimed in claim 12, wherein the common electrode driver is electrically connected to a third electrode formed on the second substrate,
And generates a common voltage pulse having a level of the first or second common voltage (Vcom1, Vcom2) provided from the voltage generating unit under the control of the timing control unit, and provides the common voltage pulse to the third electrode .

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