KR101507152B1 - Liquid crystal display and driving method there - Google Patents

Abstract

Provided is a liquid crystal display device and a method of driving the same that compensate a data voltage according to a common voltage varying according to a position of a liquid crystal panel to improve an image quality. In such a liquid crystal display device, pixel regions are defined in a region where a plurality of data lines and gate lines cross each other, a liquid crystal panel in which pixel electrodes and common electrodes for applying an electric field to liquid crystal cells, A data driver for supplying a data voltage to the pixel electrode, and a common voltage supplied from the voltage generator and a common voltage for each position of the liquid crystal panel previously stored are compared with each other And a data modulation unit for calculating the difference voltage, compensating the data voltage by the difference voltage, and supplying the compensated data voltage to the data driver.

Liquid crystal display, data voltage, compensation, common voltage

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device and a driving method thereof.

2. Description of the Related Art A liquid crystal display (LCD) is a display device that displays a desired image by adjusting the light transmittance of a liquid crystal using an electric field.

Such a liquid crystal display device mainly comprises a liquid crystal panel in which liquid crystal cells are arranged in a matrix form, and a driving circuit for driving the liquid crystal panel. In the liquid crystal panel, an upper substrate and a lower substrate, on which electric field generating electrodes are respectively formed, are arranged so as to face each other, and a liquid crystal layer for adjusting light transmittance is provided between the two substrates.

Fig. 1 is a circuit diagram showing unit pixels of an ordinary liquid crystal display device equivalently.

Referring to FIG. 1, in a typical liquid crystal display device, a plurality of gate lines GL and a plurality of data lines DL are intersected on a substrate, and regions defined by intersections are defined as a plurality of pixel regions. In each pixel region, a thin film transistor (TFT) for driving the liquid crystal cell Clc and a storage capacitor Cst for holding the voltage of the liquid crystal cell Clc are formed.

In the liquid crystal cell Clc, the arrangement of the liquid crystal molecules is changed by the electric field applied to the liquid crystal layer, thereby adjusting the light amount of the transmitted light or blocking the light. At this time, the electric field applied to the liquid crystal layer is generated by the data voltage applied to the pixel electrode 11 and the common voltage Vcom applied to the common electrode 12. [

Fig. 2 is a waveform diagram showing a kickback voltage, and shows a charge amount of a data pulse to be applied to a scan pulse SCP supplied to a gate line (GL in Fig. 1) and a liquid crystal cell (Clc in Fig. 1).

2, the scan pulse SCP includes a gate high voltage VGH for turning on the thin film transistor TFT, a turn-off signal for turning on the thin film transistor TFT, And the gate-low voltage (VGL) for causing the gate to be turned on.

During the scanning period in which the scan pulse SCP maintains the gate high voltage VGH, the liquid crystal cell charges the data voltage Vdata supplied with the gamma voltage, and the storage capacitor Cst charges the gate high voltage VGH The data voltage (Vdata) applied to the liquid crystal cell is maintained for a predetermined time until the voltage is applied again.

At this time, the charged amount Vp of the data voltage charged in the liquid crystal cell may be different for each pixel due to the parasitic capacitance (Cgd in FIG. 1) existing between the electrode terminal of the thin film transistor TFT and the liquid crystal cell electrode in each pixel , And thus, the kickback voltage (? Vp) is also different, which is a main factor for hindering the image quality.

The reason why the charged amount (Vp) and the kickback voltage (? Vp) of the data voltage charged in the liquid crystal cell are different may be as follows.

First, the characteristics of the common voltage vary depending on the position of the liquid crystal panel.

Since the liquid crystal and the display image are deteriorated when a voltage of the same polarity is continuously applied to the liquid crystal cell, the liquid crystal cell is charged with an alternate data voltage (Vdata) whose polarity is periodically inverted.

This data voltage Vdata is inverted by setting the common voltage Vcom applied to the common electrode 12 to the central electric potential and the common voltage Vcom is applied to all the pixels at the same level .

However, in the liquid crystal display according to the related art, since the common voltage Vcom is applied through the driving circuit provided only on one side, the characteristic of the common voltage differs from the driving circuit.

Further, a capacitor coupling effect is caused by the parasitic capacitance (Cgd in FIG. 1) existing between the electrode terminal of the thin film transistor (TFT) in each pixel and the liquid crystal cell electrode, so that the common voltage Vcom becomes variable .

As a result, the level of the data voltage (Vdata) inverted around the common voltage is applied asymmetrically as the common voltage is varied, so that the charging voltage Vp of the data voltage charged in the liquid crystal cell and the kickback voltage (? Vp) is different.

Second, it is the delay of the gate signal.

A pixel located at a portion adjacent to the gate driver in the entire region of the liquid crystal panel has almost no delay in signal, and the amount of the liquid crystal cell Clc is relatively large. On the other hand, since the delay difference of the signal increases as the distance from the gate driver is increased, the charge amount of the liquid crystal cell Clc becomes smaller as the pixel located on the opposite side of the gate driver.

Therefore, the kickback voltage Vp is varied due to the difference in the amount of charge for each pixel, and thus the luminance of the portion relatively away from the luminance of the portion adjacent to the gate driver on the liquid crystal panel is different from each other.

As described above, since the kickback voltage (? Vp) is different according to each position of the liquid crystal panel, the image quality is not uniform overall and the data voltage (Vdata) applied to the pixel electrode of the liquid crystal cell substantially fluctuates, ) Is generated.

In addition, there is a problem that the DC component exists due to the asymmetry of the positive and negative polarities based on the common voltage, which causes image sticking.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a liquid crystal display device and a method of driving the same that compensate a data voltage according to a common voltage varying according to a position of a liquid crystal panel, thereby improving image quality.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

According to an aspect of the present invention, there is provided a liquid crystal display device including pixel regions formed at intersections of a plurality of data lines and gate lines, and a liquid crystal cell and an electric field applied to the liquid crystal cell A liquid crystal panel in which a pixel electrode and a common electrode are formed; A voltage generator for supplying the common voltage to the common electrode; A data driver for supplying a data voltage to the pixel electrode; And a control unit for calculating a difference voltage by comparing an actual common voltage supplied from the voltage generating unit with a common voltage for each position of the liquid crystal panel stored in advance and compensating the data voltage by the difference voltage, And a modulation section.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display, the method comprising: generating a data control signal necessary for driving a liquid crystal panel according to a synchronization signal input from the outside; Storing a common voltage for each position of the liquid crystal panel in advance; Supplying an actual common voltage to the liquid crystal panel; Calculating a difference voltage by comparing the actual common voltage and a common voltage for each position of the liquid crystal panel; Compensating a data voltage based on the difference voltage; And supplying the compensated data voltage to the liquid crystal panel according to the data control signal.

The details of other embodiments are included in the detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the specification.

The liquid crystal display device according to the present invention as described above has flicker levels uniformly distributed over the entire liquid crystal panel, thereby eliminating flicker partially generated according to the position of the liquid crystal panel, It is possible to suppress the asymmetry of the level of the data voltage and to suppress the afterimage.

Hereinafter, a liquid crystal display device and a driving method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a block diagram schematically showing a configuration of a liquid crystal display device according to an embodiment of the present invention, and FIG. 4 is a conceptual diagram for explaining a data modulation part of a liquid crystal display device according to an embodiment of the present invention.

3, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel 110, a data driver 210, a gate driver 220, a timing controller 230, a voltage generator 240, And a data modulation unit 250. [

The liquid crystal panel 110 includes the gate lines GL1 to GLn in the horizontal direction and the data lines DL1 to DLm in the vertical direction arranged in a matrix form and the intersecting gate lines GL1 to GLn, (DL1 to DLm).

Each pixel is filled with a liquid crystal material equivalent to a liquid crystal cell Clc, a thin film transistor (TFT) for driving the liquid crystal cell Clc is disposed, and a voltage charged in the liquid crystal cell Clc is supplied for a predetermined time A storage capacitor Cst is formed.

The liquid crystal panel 110 thus configured displays an image on each pixel according to a scan signal supplied through the gate lines GL1 to GLn and a data voltage supplied through the data lines DL1 to DLm.

In detail, when the gate high voltage VGH is supplied from the gate lines GL1 to GLn, the thin film transistor TFT is turned on and applied from the data lines DL1 to DLm And supplies the data voltage to the liquid crystal cell Clc. Then, the liquid crystal cell Clc is charged with the difference voltage between the data voltage and the common voltage Vcom to display a desired image.

Thereafter, when the gate line voltage VGL is supplied from the gate lines GL1 to GLn, the thin film transistor TFT is turned off, and the data voltage charged in the liquid crystal cell Clc is applied to the storage capacitor Cst And is maintained for one frame period. Thus, the displayed image is held until the next gate high voltage VGH is applied.

The timing controller 230 rearranges the red, green, and blue digital pixel data R, G, and B data input from the outside and supplies them to the data driver 210. A gate control signal GCS for controlling the driving timing of the gate driving unit 220 by using the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync and the clock CLK, the driving of the data driving unit 230 And generates a data control signal DCS for controlling the timing.

The gate driver 220 supplies a scan signal sequentially shifted to the gate lines GL1 to GLn according to a gate control signal GCS supplied from the timing controller 230. [ Here, the scan signal is a pulse signal in which the gate high voltage VGH supplied during one horizontal period and the gate low voltage VGL supplied during the remaining period are alternated.

The data driver 210 supplies red, green, and blue digital pixel data (R, G, and B DATA) input from the timing controller 230 in response to a data control signal DCS supplied from the timing controller 230, Voltage, and supplies it to the data lines DL1 to DLm.

At this time, the data voltage is supplied at a preset gamma voltage in accordance with the driving voltage characteristic of the liquid crystal cell Clc.

5, the data driver 210 includes a plurality of driver integrated circuits (D-ICs) (SIC-1 to SIC-8), and a plurality of driver ICs (SIC-1 to SIC-8) are mounted on a tape carrier package (TCP) or a chip-on film (COF).

The gate driver 220 may also include a plurality of driver integrated circuits (not shown) as in the data driver 210.

3, the voltage generating unit 240 generates gate voltages VGH and VGL necessary for driving the liquid crystal panel 110 and a common voltage Vcom to be provided to the common electrode of the liquid crystal panel 110, And so on.

The gate voltages VGH and VGL are control signals for turning on and off the thin film transistors TFT of the liquid crystal panel 110. When the gate high voltages VGH are applied to the thin film transistors TFT, And when the gate low voltage VGL is applied, the thin film transistor TFT is turned off.

The common voltage Vcom is a voltage that becomes the central electric potential of the pixel drive, and a voltage of the same level is applied to all the pixels irrespective of the position of the liquid crystal panel 110.

For example, the common voltage Vcom may be applied to one side of the upper side or the upper side near the data driver 210 of the liquid crystal panel 110, and conversely to the lower side or both sides as the starting point, As shown in FIG.

The data modulator 250 compensates the data voltage as the common voltage Vcom supplied from the voltage generator 240 varies according to the position of the liquid crystal panel to have the same effect as that of the compensated common voltage .

4, the data modulating unit 250 modulates the data (data) by using the horizontal and vertical coordinates (x, y) of the liquid crystal panel, the data voltage data, and the polarity The voltage is compensated.

In general, the common voltage supplied to the liquid crystal panel 110 varies depending on the internal environment of the liquid crystal panel 110 (such as the parasitic capacitance or the signal delay of the gate) They have different common voltages.

Here, the common voltage (optimal Vcom) by position means a common voltage when the liquid crystal panel has a uniform filcker level irrespective of the position of the liquid crystal panel.

Therefore, when the common voltage applied to the liquid crystal panel 110 as a whole does not become the central electric potential of the pixel driving during the driving, and the common voltage for the internal positions becomes the central electric potential of the pixel driving, The level of the data voltage to be applied to the liquid crystal cell is applied asymmetrically. When the charged amount of the data voltage is changed, the kickback voltage is changed, and the data voltage applied to the liquid crystal cell may be substantially changed.

Therefore, in the present embodiment, the data modulator 250 attempts to compensate the data voltage based on the common voltage for each position that varies depending on each position of the liquid crystal panel.

The data modulator 250 for this purpose is driven according to the control of the timing controller 230 together with a control signal for controlling the driving timing of the data driver 210. The timing controller 230 and the timing controller 230, Or may be incorporated in the timing controller 230. [

5 is a detailed block diagram illustrating a data modulation unit of a liquid crystal display device according to an embodiment of the present invention.

5, the data modulator 250 basically includes a lookup table 251, a comparator 253, and a compensator 255. The lookup table 251 includes a lookup table 251,

The lookup table 251 stores the common voltage and the polarity (POL) of the difference voltage according to the position of the liquid crystal panel 110, respectively.

At this time, the optimal common voltage is tabulated and stored according to the horizontal and vertical coordinates (x, y) of the liquid crystal panel 110.

As described above, the common voltage by position means a common voltage when the liquid crystal panel has a uniform filcker level regardless of the position of the liquid crystal at a specific position of the liquid crystal panel, and the flicker level is related to the charged amount of the data voltage .

When the position control signal m (x, y) for the specific position of the liquid crystal panel 110 is inputted from the outside, the comparator 253 compares the position control signal m (x, y) Up table 251 and compares the actual common voltage (actual Vcom) supplied from the voltage generator 240 with the common voltage per position read from the look-up table 251 with each other.

Here, the position control signal m (x, y) is a signal for controlling the position based on the horizontal and vertical coordinates (x, y) of the liquid crystal panel 110.

As a result of comparison, the difference voltage between the actual common voltage (actual Vcom) supplied through the voltage generator 240 and the common voltage (optimal Vcom) by position is calculated and the polarity of the difference voltage is stored in the lookup table 251 .

The compensating unit 255 compensates the data voltage based on the difference voltage calculated by the comparator 253. At this time, the compensation of the data voltage is performed by a method of subtraction or addition according to the polarity of the difference voltage stored in the look-up table 251. [

After the compensation, the compensated data voltage Vdata 'is supplied to the data driver ICs SIC-1 to SIC-8 of the data driver 210, respectively.

Hereinafter, the operation principle of compensating the data voltage Vdata through the comparator 253 and the data voltage compensator 255 will be described in detail.

FIG. 6 is a liquid crystal panel showing an example in which a liquid crystal display according to an embodiment of the present invention is divided according to positions, FIG. 7 is a waveform diagram showing a relationship between a common voltage and an actual common voltage for each position before data voltage compensation And FIG. 8 is a waveform diagram showing the relationship between the common voltage and the actual common voltage for each position after data voltage compensation.

FIGS. 7 and 8 show the actual common voltage and the common voltage and the data voltage for each position with respect to the positions a, b, and c in FIG. 6, respectively.

The a position, the b position, and the c position shown in FIG. 6 represent an area including one or more pixels, and have information on the horizontal and vertical coordinates (x, y).

Referring to the graph of FIG. 7, the amount of charge of the pixel is relatively large at the position a, and the kickback voltage (ΔVpa) is relatively small. In the positions b and c, It can be seen that the voltages (? Vpb,? Vpc) are relatively large.

This is because the pixel located near the gate driver has a small amount of signal delay and has a large charge amount, and the charge amount can be reduced as the distance from the gate driver is increased.

The common voltage Vcom1 supplied through the voltage generator 240 and the common voltage Vcom2_a according to the position are the same at the position a before compensating the data voltage, Becomes zero. At the positions b and c, it can be seen that the levels of the actual common voltage Vcom1 and the common voltages Vcom2_b and Vcom2_c according to positions are different, and positive and negative differential voltages? Vb and? Vc are generated, respectively.

At this time, if the actual common voltage Vcom1 is the central electric potential of the pixel drive, the pre-compensation data voltage Vdata1 is different from the common voltage Vcom2_b and Vcom2_c at the position b and at the position c, , And? Vc are generated, flickers are present.

That is, when the actual common voltage Vcom1 and the position common voltage Vcom2_a coincide with each other as in the position a, the charging amount of the data voltage Vdata1 applied with the actual common voltage Vcom1 as the central electric potential (The hatched display area) of the data voltage Vdata1 inverted to the center potential by the common voltage Vcom2_a for each position coincides with the charging amount (hatched display area).

However, at the b-position and the c-position, the charge amount (dot display area) of the data voltage Vdata1 applied with the actual common voltage Vcom1 as the central electric potential and the common voltages Vcom2_b and Vcom2_c (Hatched display areas) of the data voltage Vdata1 are not equal to each other.

In other words, when the common voltages Vcom2_b and Vcom2_c at different positions from the level of the actual common voltage Vcom1 are the central potentials of the pixel driving, the common voltages Vcom2_b and Vcom2_c at the respective positions are set to the data voltages The polarity level is applied asymmetrically, and a residual image appears.

Therefore, the data voltages at the b-position and the c-position where the charged amount of the data voltage Vdata1 is not equal are compensated as shown in Fig.

At the time of compensation, the difference voltage (? Vb,? Vc) between the optimum common voltages Vcom2_b and Vcom2_c and the actual common voltage Vcom1 is calculated and the calculated difference voltage is subtracted or added according to the polarity of the data voltage to compensate the data voltage do.

Here, the difference voltages? Vb and? Vc are positive or negative depending on the reference value.

For example, when the level of the position common voltage Vcom2_b is higher than the level of the actual common voltage Vcom1 with reference to the position common voltages Vcom2_b and Vcom2_c, these differential voltages? Vb become positive, When the level of the position common voltage Vcom2_c is lower than the level of the actual common voltage Vcom1, these difference voltages? Vc become negative.

When the difference voltage DELTA Vb is a positive number, it is compensated by subtracting the difference voltage Vbata from the pre-compensation data voltage Vdata1 as shown in the following equation (1).

When the difference voltage? Vc is negative, it is compensated by adding the difference voltage? Vc to the pre-compensation data voltage Vdata1 as shown in the following equation (1).

Here, Vdata2 is the compensated data voltage, Vdata1 is the pre-compensation data voltage, and? V is the difference voltage? Vb and? Vc.

According to this, the compensated data voltages Vdata2_b and Vdata2_c at the b-position and the c-position compensate the data voltage charge amount (dot display area) when the actual common voltage Vcom1 is at the center potential and the common voltages Vcom2_b and Vcom2_c (The hatched display region) is the same as the data voltage charged amount

Therefore, the b position and the c position after compensation have the flicker according to the position like the flicker at the position a.

Thereby, regardless of the position of the liquid crystal panel, the liquid crystal panel has the uniformly uniform flicker, so that the same effect as that of inputting the common voltage Vcom2 for each position can be obtained without varying the actual common voltage Vcom1 according to the position of the liquid crystal panel .

Hereinafter, a driving method of a liquid crystal display device according to an embodiment of the present invention will be described.

9 is a flowchart illustrating a method of driving a liquid crystal display according to an embodiment of the present invention.

Referring to FIG. 9, a method of driving a liquid crystal display according to an exemplary embodiment of the present invention includes a first step of receiving a video data signal to be displayed from the outside and a data control (S10).

Next, a common voltage (optimum Vcom) for each position of the liquid crystal panel is stored in advance (S20).

The common voltage (optimal Vcom) by position means a common voltage when the liquid crystal panel has a uniform filcker level irrespective of the position of the liquid crystal panel, and has a different voltage level depending on each position of the liquid crystal panel.

The common voltage (optimal Vcom) for each position can be detected through a simulation, a separate measuring instrument, or the like, and can be tabulated and stored according to the horizontal and vertical coordinates (x, y) of the liquid crystal panel.

Then, an actual common voltage (actual Vcom) is supplied to the liquid crystal panel (S30).

The actual common voltage is supplied through the driving circuit portion of the liquid crystal panel and a voltage of the same level is applied to all the pixels irrespective of the position of the liquid crystal panel.

Then, the common voltage for each position of the liquid crystal panel is compared with the actual common voltage (S40).

The comparison step includes the steps of receiving a position control signal m (x, y) according to each position of the liquid crystal panel in detail, And comparing the actual common voltage with the common voltage for each position.

As a result of the comparison, the difference voltage between the common voltage and the actual common voltage is calculated (S50).

Thereafter, the data voltage is compensated based on the calculated difference voltage (S60).

The compensation method is performed by subtracting or adding the difference voltage to the data voltage, and the subtraction or addition is selectively determined according to the polarity of the difference voltage.

For example, when calculating the difference voltage based on the common voltage by position, if the common voltage per position is larger than the actual common voltage, the difference voltage becomes positive. The compensation method accordingly compensates by subtracting the data voltage before compensation by the difference voltage.

On the other hand, when the common voltage per position is smaller than the actual common voltage and the difference voltage is negative, its compensation method follows a method of adding the data voltage before compensation to the difference voltage.

After compensation, the compensated data voltage is supplied to the liquid crystal panel (S70).

Accordingly, it is possible to provide a liquid crystal display device in which the image quality is further improved and the afterimage is eliminated by providing the liquid crystal panel having a uniform flicker level as a whole regardless of its position.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

1 is a circuit diagram showing equivalent unit pixels of a general liquid crystal display device.

2 is a waveform diagram showing a data voltage charged in a unit pixel of a general liquid crystal display device.

3 is a block diagram schematically showing a configuration of a liquid crystal display device according to an embodiment of the present invention.

4 is a conceptual diagram illustrating a data modulation unit of a liquid crystal display device according to an embodiment of the present invention

5 is a detailed block diagram illustrating a data modulation unit of a liquid crystal display device according to an embodiment of the present invention.

6 is a view illustrating an example of a liquid crystal display according to an exemplary embodiment of the present invention.

7 is a waveform diagram showing a relationship between a common voltage and an actual common voltage for each position before data voltage compensation.

8 is a waveform diagram showing a relationship between a common voltage and an actual common voltage for each position after data voltage compensation.

9 is a flowchart illustrating a method of driving a liquid crystal display according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

110: liquid crystal panel 210: data driver

220: Gate driver 230: Timing controller

240: voltage generator 250: data modulator

251: Lookup table

253: comparison unit 255: compensation unit

SIC-1 to SIC-8: An integrated circuit for a data driver

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Claims (12)

A liquid crystal panel in which pixel regions are defined in a region where a plurality of data lines and gate lines cross each other, and pixel electrodes and common electrodes for applying an electric field to the liquid crystal cells are formed in the pixel regions; A voltage generator for supplying the common voltage to the common electrode; A data driver for supplying a data voltage to the pixel electrode; And A data modulation unit for calculating a difference voltage by comparing an actual common voltage supplied from the voltage generating unit with a common voltage for each position of the liquid crystal panel stored in advance and compensating the data voltage by the difference voltage, part And the liquid crystal display device. The method according to claim 1, Generates various control signals including a vertical synchronizing signal (Vsync), a horizontal synchronizing signal (Hsync) and a clock (CLK) necessary for driving the liquid crystal panel, and generates a data control signal to control the driving timing of the data driving unit Wherein the timing controller further comprises: 3. The method of claim 2, Wherein the data modulator is built in the timing controller. The method according to claim 1, Wherein the common voltage for each position is a common voltage in a state having a uniform filcker level irrespective of a specific position of the liquid crystal panel. 5. The method of claim 4, Regardless of the specific position of the liquid crystal panel, a uniform flicker level is characterized in that the charge amount of the data voltage when the actual common voltage has the central potential and the charge voltage of the data voltage when the common voltage per position is the central potential are equal . The method according to claim 1, Wherein the data modulator comprises: A lookup table storing a common voltage for each position according to each position of the liquid crystal panel; A comparator that reads a common voltage for each position of the liquid crystal panel stored in the lookup table and compares a common voltage for each position with an actual common voltage supplied through the voltage generator and calculates a difference voltage; And A compensation unit for subtracting or adding the data voltage by the difference voltage, And the liquid crystal display device. The method according to claim 6, Wherein the comparison unit receives a position control signal corresponding to a position of the liquid crystal panel. The method according to claim 6, And the difference voltage is positive or negative. 9. The method of claim 8, Wherein the compensation unit subtracts the data voltage by the difference voltage when the difference voltage is positive and adds the data voltage by the difference voltage when the difference voltage is negative. Generating a data control signal necessary for driving the liquid crystal panel in accordance with a synchronization signal input from the outside; Storing a common voltage for each position of the liquid crystal panel in advance; Supplying an actual common voltage to the liquid crystal panel; Calculating a difference voltage by comparing the actual common voltage and a common voltage for each position of the liquid crystal panel; Compensating a data voltage based on the difference voltage; And Supplying the compensated data voltage to the liquid crystal panel according to the data control signal And a driving method of the liquid crystal display device. 11. The method of claim 10, Wherein the step of comparing the actual common voltage with a common voltage according to a position of the liquid crystal panel comprises: Receiving a position control signal corresponding to a position of the liquid crystal panel; Loading the common voltage for each position according to the input position control signal; And Comparing the position common voltage with the actual common voltage And a driving method of the liquid crystal display device. 11. The method of claim 10, Wherein compensating the data voltage comprises: Subtracts the difference voltage from the data voltage when the difference voltage is a positive number, and adds the difference voltage to the data voltage when the difference voltage is negative.

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