KR100705619B1 - Method of driving for liquid crystal display and circuit thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a liquid crystal display device and a device thereof, and to increase the contrast ratio (CR) in the next frame by averaging R / G / B data input to the LCD module for one to several frames. By adjusting the gamma voltage in the direction to make the video, it is possible to minimize the blurring when the video is implemented.

The driving method of the liquid crystal display device of the present invention for this purpose is to obtain a sum of red (R) / green (G) / blue (B) data corresponding to one frame; Dividing the sum of the red (R) / green (G) / blue (B) data by the number of pixels of the red (R) / green (G) / blue (B) data corresponding to one frame to obtain an average value; Comparing the calculated average value with an average value of all frames and outputting a difference value; And changing the gamma of the red (R) / green (G) / blue (B) data for each frame based on the calculated difference value.

Description

Method of driving a liquid crystal display device and a circuit thereof {METHOD OF DRIVING FOR LIQUID CRYSTAL DISPLAY AND CIRCUIT THEREOF}

1 is a waveform diagram showing a change in luminance according to data of a general liquid crystal display

2 is a waveform diagram showing a change in luminance according to data modulation of a conventional liquid crystal display device.

3 is a view for explaining a method of driving a conventional liquid crystal display device.

4 is a block diagram showing a driving circuit of a conventional liquid crystal display device.

5 is a graph showing conventional modulation data

6 is a block diagram showing a driving circuit of the liquid crystal display according to the present invention.

7 is a block diagram showing a driving circuit of another liquid crystal display according to the present invention.

8 is a graph illustrating an example of a gamma curve of the gamma lookup table illustrated in FIGS. 6 and 7.

9 is an operation timing diagram of the control signal illustrated in FIGS. 6 and 7.

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

102, 104, and 106: first to third adders

112, 114, and 116: first to third trimmers

122, 124, 126: first to third comparators

132, 134, 136: first to third multipliers

140: fourth adder 150: fourth trimmer

160: fourth comparator 170: gamma lookup table

180: gamma IC 210: adder

220: winning machine 230: comparator

240: gamma lookup table 250: gamma IC

The present invention relates to a method for driving a liquid crystal display device and a device thereof, and in particular, a clear video screen similar to a CRT screen by minimizing a blurring inevitably occurring in a hold type when a video is implemented. The present invention relates to a driving method of a liquid crystal display device and a device thereof.

In general, a liquid crystal display (LCD) displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. An active matrix liquid crystal display device in which switching elements are formed for each liquid crystal cell is suitable for displaying moving images. As a switching element used in an active matrix type liquid crystal display device, a thin film transistor (hereinafter, referred to as TFT) is mainly used.

As can be seen in Equations 1 and 2, the liquid crystal display has a disadvantage in that the response speed is slow due to the inherent viscosity and elasticity of the liquid crystal.

(gamma)는 액정분자의 회전점도(rotational viscosity)를 각각 의미한다. Where τ _r is the rising time when voltage is applied to the liquid crystal, Va is the applied voltage, and V _F is the Freederick Transition Voltage at which the liquid crystal molecules begin their inclined motion, d Is the cell gap of the liquid crystal cell,

(gamma) means rotational viscosity of liquid crystal molecules, respectively.

Here, τ _f denotes a falling time during which the liquid crystal is restored to its original position by the elastic restoring force after the voltage applied to the liquid crystal is turned off, and K denotes the elastic modulus inherent to the liquid crystal.

The liquid crystal response speed of the TN mode may vary depending on the physical properties of the liquid crystal material, the cell gap, and the like, but usually has a rising time of 20-80 ms and a polling time of 20-30 ms. Since the response speed of the liquid crystal is longer than one frame period (NTSC: 16.67 ms) of the video, the screen is blurred in the video because the voltage charged in the liquid crystal cell proceeds to the next frame as shown in FIG. 1. Motion blurring phenomenon appears.

Referring to FIG. 1, a conventional liquid crystal display device does not reach a desired display luminance BL when the data VD changes from one level to another due to a slow response speed when a video is implemented. It will not be able to express color and brightness. As a result, the motion blurring phenomenon occurs in the liquid crystal display, and the display quality is degraded due to the decrease in the contrast ratio.

In order to solve the slow response speed of the liquid crystal display device, U.S. Patent No. 5,495,265 and PCT International Publication No. WO 99/09967 use a lookup table to modulate the data according to the change of data (hereinafter, 'high speed driving Has been proposed. This high speed driving method modulates data in the same principle as in FIG. 2.

을 크게 함으로써 액정의 응답속도를 빠르게 한다. 따라서, 고속 구동방법을 이용하는 액정표시장치는 액정의 늦은 응답속도를 데이터값의 변조로 보상하여 동화상에서 모션 블러링(Motion Burring) 현상을 완화시킴으로써 원하는 색과 휘도로 화상을 표시할 수 있게 된다. Referring to FIG. 2, the conventional high speed driving method modulates the input data VD and applies the modulation data MVD to the liquid crystal cell to obtain a desired luminance MBL. This high-speed driving method uses Equation 1 based on whether or not the data changes so as to obtain a desired luminance corresponding to the luminance value of the input data within one frame period.

Increase the response speed of the liquid crystal by increasing. Accordingly, the liquid crystal display device using the high speed driving method compensates the late response speed of the liquid crystal by modulating the data value, thereby alleviating the motion blurring phenomenon in the moving image, thereby displaying an image with a desired color and luminance.

In other words, the fast driving method compares the upper bit MSB of each of the previous frame Fn-1 and the current frame Fn, and if there is a change in the upper bit MSB, the modulation data corresponding to the lookup table ( Mdata) is selected and modulated as shown in FIG. 3. This high-speed driving method modulates only the upper few bits to reduce the capacity burden of the memory in hardware implementation. The high speed drive device implemented as described above is illustrated in FIG. 4.

Referring to FIG. 4, the conventional high speed drive device is commonly connected to the frame memory 43 connected to the upper bit bus line 42 and the output terminals of the upper bit bus line 42 and the frame memory 43. The lookup table 44 is provided.

The frame memory 43 stores the upper bit MSB for one frame period and supplies the stored data to the lookup table 44. Here, the upper bit MSB is set to the upper four bits among the eight bits of the source data RGB.

The lookup table 44 selects an upper bit MSB of the current frame Fn input from the upper bit bus line 42 and an upper bit MSB of the previous frame Fn-1 input from the frame memory 43. The modulation data (Mdata) is selected by comparing with Table 1 or Table 2 below. The modulated data Mdata is added to the lower bit LSB from the lower bit bus line 41 and supplied to the liquid crystal display.

division 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 0 2 3 4 5 6 7 9 10 12 13 14 15 15 15 15 One 0 One 3 4 5 6 7 8 10 12 13 14 15 15 15 15 2 0 0 2 4 5 6 7 8 10 12 13 14 15 15 15 15 3 0 0 One 3 5 6 7 8 10 11 13 14 15 15 15 15 4 0 0 One 2 4 6 7 8 9 11 12 13 14 15 15 15 5 0 0 One 2 3 5 7 8 9 11 12 13 14 15 15 15 6 0 0 One 2 3 4 6 8 9 10 12 13 14 15 15 15 7 0 0 One 2 3 4 5 7 9 10 11 13 14 15 15 15 8 0 0 One 2 3 4 5 6 8 10 11 12 13 15 15 15 9 0 0 One 2 3 4 5 6 7 9 11 12 13 14 15 15 10 0 0 One 2 3 4 5 6 7 8 10 12 13 14 15 15 11 0 0 One 2 3 4 5 6 7 8 9 11 12 14 15 15 12 0 0 One 2 3 4 5 6 7 8 9 10 12 14 15 15 13 0 0 One 2 3 3 4 5 6 7 8 10 11 13 15 15 14 0 0 One 2 3 3 4 5 6 7 8 9 11 12 14 15 15 0 0 0 One 2 3 3 4 5 6 7 8 9 11 13 15

division 0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 0 0 32 48 64 80 96 112 144 160 192 208 224 240 240 240 240 16 0 16 48 64 80 96 112 128 160 192 208 224 240 240 240 240 32 0 0 32 64 80 96 112 128 160 192 208 224 240 240 240 240 48 0 0 16 48 80 96 112 128 160 176 208 224 240 240 240 240 64 0 0 16 48 64 96 112 128 144 176 192 208 224 240 240 240 80 0 0 16 32 48 80 112 128 144 176 192 208 224 240 240 240 96 0 0 16 32 48 64 96 128 144 160 192 208 224 240 240 240 112 0 0 16 32 48 64 80 112 144 160 176 208 224 240 240 240 128 0 0 16 32 48 64 80 96 128 160 176 192 224 240 240 240 144 0 0 16 32 48 64 80 96 112 144 176 192 208 224 240 240 160 0 0 16 32 48 64 80 96 112 128 160 192 208 224 240 240 176 0 0 16 32 48 64 80 96 112 128 144 176 208 224 240 240 192 0 0 16 32 48 64 80 96 112 128 144 160 192 224 240 240 208 0 0 16 32 48 48 64 80 96 112 128 160 176 208 240 240 224 0 0 16 32 48 48 64 80 96 112 128 144 176 192 224 240 240 0 0 0 16 32 48 48 64 80 96 112 128 144 176 208 240

In Tables 1 and 2, the left column is the data voltage VDn-1 of the previous frame Fn-1, and the uppermost row is the data voltage VDn of the current frame Fn. Table 1 shows lookup table information in which the most significant four bits (2 ⁰ , 2 ¹ , 2 ² , 2 ³ ) are expressed in decimal. Table 2 shows lookup table information when the weights of the most significant 4 bits (2 ⁴ , 2 ⁵ , 2 ⁶ , 2 ⁷ ) are applied among 8 bits of data.

However, the conventional fast driving method finds modulation data (Mdata) listed in the lookup table using a lookup table comparing only upper bits, so that the continuity of the modulation data (Mdata) is lost or adjacent modulation data compared to the actual gray level of the video data. Data overshoot occurs between (Mdata). As a result, as shown in FIG. 5, the value of the modulation data leaps between the gray level of the actually input data and the gray level of the modulated data, thereby causing a large change in luminance.

To solve this problem, it is necessary to increase the memory size of the frame memory and the lookup table, compare the source data with full bits (8 bits), and derive the selected full bit modulation data according to the result.

However, the full bit comparison has another problem in that the memory size of the frame memory and the lookup table is increased, thereby increasing the cost required for the circuit configuration. For example, the memory size of a lookup table that compares 8-bit source data and selects 8-bit modulation data Mdata is 65536 × 8 = 524 kbits.

In addition, the liquid crystal display according to the related art stores red (R), green (G), and blue (B) data corresponding to one frame in a frame memory to store the data currently input. Comparison was made in units of 1 pixel. However, this method has a problem of increasing cost and increasing the size of a printed circuit board (PCB) because the frame memory must be used separately. In addition, many implementation problems arise from accessing RAM.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to average the R / G / B data input to the LCD module for one frame to several frames, and then, in the next frame, The present invention provides a method and a device for driving a liquid crystal display device which minimizes blurring when a moving picture is realized by adjusting a gamma voltage in a direction of increasing a contrast ratio.

In addition, another object of the present invention is to provide a method and a device for driving a liquid crystal display device which reduces manufacturing costs and reduces the size of a printed circuit board (PCB) by using a basic memory built in a scalar instead of a frame memory. It is.

The driving circuit of the liquid crystal display device according to the present invention for achieving the above object,

An adder for receiving red (R) / green (G) / blue (B) data corresponding to one frame and obtaining a sum thereof;

The average value is divided by dividing the sum of red (R) / green (G) / blue (B) data received from the adder by the number of pixels of red (R) / green (G) / blue (B) data corresponding to one frame. To obtain a lift;

A comparator for comparing the average value received from the multiplier with the average value of all frames and outputting the difference value; And

And a gamma lookup table configured to change the gamma of the red (R) / green (G) / blue (B) data for each frame according to the difference value received from the comparator.

The adder and the multiplier may be configured to operate in opposite directions by the control signal H_DE.

The adder operates in an enable period of the control signal, and the multiplier operates in a disable period of the control signal.

The control signal is enabled when the first data enable signal DE of one frame is enabled and is configured to be disabled when the last data enable signal DE is disabled.

A driving circuit of another liquid crystal display device of the present invention for achieving the above object,

First to third adders for receiving red (R) / green (G) / blue (B) data corresponding to one line and obtaining their sums;

Pixels of red (R) / green (G) / blue (B) data corresponding to one line by adding the sum of red (R) / green (G) / blue (B) data received from the first to third adders First to third trimmers for dividing by the number to obtain an average value;

First to third comparators for comparing the average value received from the first to third multipliers with an average value of line data of the previous frame and outputting a difference value;

First to third multipliers for multiplying red (R) / green (G) / blue (B) data received from the first to third comparators by different constant values;

A fourth adder that sums values received from the first to third multipliers;

A fourth multiplier for dividing the value received from the fourth adder by 3 to determine a final gamma value corresponding to the line;

A fourth comparator comparing the final gamma value received from the fourth multiplier with a final gamma value corresponding to a line of a previous frame and outputting a difference value; And

And a gamma lookup table for changing the gamma of the red (R) / green (G) / blue (B) data for each line based on the difference value received from the fourth comparator.

The first to third adders and the first to third multipliers may be configured to operate in opposite directions by the control signal H_DE.

The first to third adders operate in an enable period of the control signal, and the first to third multipliers operate in a disable period of the control signal.

The control signal is enabled when the first data enable signal DE of one line is enabled and is configured to be disabled when the last data enable signal DE is disabled.

The driving method of the liquid crystal display device of the present invention for achieving the above object,

Obtaining a sum of red (R) / green (G) / blue (B) data corresponding to one frame;

Dividing the sum of the red (R) / green (G) / blue (B) data by the number of pixels of the red (R) / green (G) / blue (B) data corresponding to one frame to obtain an average value;

Comparing the calculated average value with an average value of all frames and outputting a difference value; And

And changing the gamma of the red (R) / green (G) / blue (B) data for each frame based on the calculated difference value.

Another method of driving the liquid crystal display device of the present invention for achieving the above object,

Obtaining a sum of red (R), green (G), and blue (B) data corresponding to one line;

Dividing the calculated sum of red (R) / green (G) / blue (B) data by the number of pixels of red (R) / green (G) / blue (B) data corresponding to one line to obtain an average value ;

Comparing the average value of the calculated average value with the line data of the previous frame and outputting the difference value;

Multiplying the calculated difference values of the red (R) / green (G) / blue (B) data by different constant values;

Summing the calculated values;

Dividing the calculated value by 3 to determine a final gamma value corresponding to the line;

Comparing the final gamma value with a final gamma value corresponding to a line of a previous frame and outputting a difference value; And

And changing the gamma of the red (R) / green (G) / blue (B) data for each line based on the calculated difference value.

Another driving method of the liquid crystal display device of the present invention for achieving the above object,

By using the above driving method, by directly controlling the gamma table of the scalar used in the LCD monitor, red (R) / green (G) / blue (B) data can be generated for each line without changing the gamma reference voltage. It is characterized by changing.

Another driving method of the liquid crystal display device of the present invention for achieving the above object,

By using the driving method, the offset and gain of analog red (R) / green (G) / blue (B) data are controlled, and the red (R) / green (G) / blue (B) line by line is controlled. The gamma of the data is changed.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

FIG. 6 is a block diagram illustrating a driving circuit of a liquid crystal display according to an exemplary embodiment of the present invention, and is configured to change gamma of red (R) / green (G) / blue (B) data for each line. It is also.

As shown in FIG. 6, the driving circuit of the liquid crystal display receives first red (R) / green (G) / blue (B) data corresponding to one line and calculates a sum of the first and second sums. Of the red (R) / green (G) / blue (B) data received from the third to third adders (102) (104) (106) and the first to third adders (102) (104) (106). The first to third multipliers 112, 114, 116 that divide the sum by the number of pixels of red (R), green (G), and blue (B) data corresponding to one line to obtain an average value. The first to third comparators 122 and 124 for comparing the average value received from the first to third multipliers 112, 114 and 116 with the average value of the line data of the previous frame and outputting the difference value. ) 126 and the first to third multiplied by different constant values to the red (R) / green (G) / blue (B) data received from the first to third comparators (122) (124, 126). Third multipliers 132, 134, 136 and the first to third multipliers 132, 134, 136 A fourth adder 140 that sums the summed values, a fourth multiplier 150 that determines a final gamma value corresponding to the line by dividing the value received from the fourth adder 140 by 3, and the fourth agent. A fourth comparator 160 comparing the final gamma value received from the multiplier 150 with a final gamma value corresponding to the line of the previous frame and outputting the difference value, and the difference value received from the fourth comparator 160. A gamma lookup table 170 for changing the gamma of red (R), green (G), and blue (B) data for each line and a gamma IC 180 are included.

The driving circuit of the liquid crystal display device installs 6-bit first to third adders (102) (104) (106) at an input portion of each channel to input an LCD for displaying an LCD. Sum operation is performed for one (R), green (G), and blue (B) data. The first to third adders 102, 104, and 106 perform an add function as a clock for each red (R) / green (G) / blue (B) data. Done. At this time, the red (R) / green (G) / blue (B) data received by the first to third adders (102, 104, 106) performs an addition function for one line. .

Here, the valid data interval for one line is determined by the data enable signal H_DE, as shown in FIG. The first to third adders 102, 104 and 106 operate in a section in which the data enable signal H_DE is 'high', and is 'low'. In the section, the first to third lifters 112, 114, and 116 operate. In this case, the first to third adders 102, 104, and 106 do not operate in the section where the data enable signal H_DE is 'low'.

The data enable signal H_DE becomes 'high' in a section where the data enable DE of one line is 'high', and 'low' becomes the falling edge of the last data enable DE. do. An operation timing of the data enable signal H_DE is illustrated in FIG. 9.

The sum of the red (R) / green (G) / blue (B) data output from the first to third adders (102, 104, 106) is the first to third multipliers (112). (R), green (G), and blue (B) data, which are inputted to (114) and 116, are divided by the number of pixels of the red (R), green (G), and blue (B) data corresponding to one line.

The data averaged by the first to third multipliers 112, 114 and 116 have a value corresponding to 1 to 64 (decimal) in the case of 6 bits. The operations of the first to third multipliers 112, 114, and 116 are performed in a blanking data section in which the data enable signal H_DE is 'low'.

The data averaged in the first to third multipliers 112, 114 and 116 is then input into the first to third comparators 122, 124 and 126, which are the next blocks, It is stored in a 6-bit latch. At this time, the data stored in the 6-bit latch unit is used to compare with the average value of the data corresponding to the line of the next frame.

The average values (a) (b) (c) of the data received by the first to third comparators 122, 124 and 126 are compared with the reference values a '(b') (c '). The reference values (a '), (b') and (c ') used herein select one value from 1 to 64 values for 6 bits and 1 to 256 values for 8 bits.

The reference values a ', b', and c 'are average values corresponding to previous lines of red (R) / green (G) / blue (B) data before the current frame.

The first to third comparators 122, 124, and 126 are the average values (a) (b) (c) and reference values () received from the first to third multipliers 112, 114, and 116. a ') (b') (c ') is compared and the difference value is output. In this case, the first to third comparators 122, 124, and 126 have average gray values of respective red (R) / green (G) / blue (B) data as reference values (a ') (b') ( c ') and search for the difference between them to create a criterion for selecting the output gamma.

Data passing through the first to third comparators 122, 124 and 126 in each channel is input to the first to third multipliers 132, 134 and 136 to determine a predetermined constant A. Multiply the gains of B, C by This gain value is different depending on the LCD panel's visual characteristics for red (R), green (G), and blue (B) data.

Values output from the first to third comparators 122, 124 and 126 are input to the fourth adder 140 to modulate the red (R) / green (G) / blue (B) data. After adding, it is printed. Then, the value output from the fourth adder 140 is input to the fourth multiplier 150 and divided into 3 (red (R) / green (G) / blue (B) data) corresponding to the line. The final average gamma value d is determined.

The final average gamma value d output from the fourth multiplier 140 is input to the fourth comparator 160 and compared with the final gamma value corresponding to the line of all frames to output the difference value.

The gamma lookup table 170 changes the gamma of the red (R) / green (G) / blue (B) data for each line based on the difference value received from the fourth comparator 160.

The above operation compares the average value of each gamma of red (R) / green (G) / blue (B) data corresponding to one line of the previous frame with the average value corresponding to the line of the current frame to change the gamma. It is.

FIG. 7 is a block diagram illustrating a driving circuit of another liquid crystal display according to an exemplary embodiment of the present invention, for changing gamma of red (R) / green (G) / blue (B) data for each frame. FIG. It is a block diagram.

As shown in FIG. 7, the driving circuit of the liquid crystal display device adds 210 (R) / green (G) / blue (B) data corresponding to one frame and obtains a sum thereof. ) And the sum of the red (R) / green (G) / blue (B) data received from the adder (210) of the red (R) / green (G) / blue (B) data corresponding to one frame. A multiplier 220 that obtains an average value by dividing the number of pixels, a comparator 230 that compares the average value received from the multiplier 220 with an average value of all frames, and outputs a difference value from the comparator 230 And a gamma lookup table 240 and a gamma IC 250 for changing the gamma of the red (R), green (G), and blue (B) data according to the received difference value.

FIG. 8 is a graph illustrating an example of a gamma curve of the gamma lookup table illustrated in FIGS. 6 and 7.

Assuming that the average gamma value for one line of the previous frame is ⓐ, and the gamma corresponding to that line of the previous frame is ⓑ, the difference between ⓐ and ⓑ is shown in FIG. 6. The gamma curve corresponding to the line is detected by the driving circuit and the gamma reference voltage is output by changing the gamma A to gamma B.

By repeating the above operation, blurring is reduced by increasing the contrast ratio when the video is implemented.

In the present invention, the red (R) / green (G) / blue (B) data can be changed without changing the gamma reference voltage by directly controlling the gamma table of the scaler used in the LCD monitor.

It also controls the offset and gain of analog red (R), green (G), and blue (B) data to change the gamma of red (R), green (G), and blue (B) data per line. It may be.

The present invention is not limited to the above-described embodiments, but can be variously modified and changed by those skilled in the art, which should be regarded as included in the spirit and scope of the present invention as defined in the appended claims. something to do.

As described above, according to the driving method and the device of the present invention, the R / G / B data input to the LCD module is averaged for one to several frames, the contrast ratio (Contrast) in the next frame By adjusting the gamma voltage in the direction of increasing the ratio, it is possible to minimize the blurring that occurs when the video is implemented. In addition, the viewing angle due to the contrast ratio (CR) can be increased, the cost can be reduced by not using the frame memory, and the size of the printed circuit board (PCB) can be reduced. have.

Claims (13)

In the driving circuit of the liquid crystal display device, An adder for receiving red (R) / green (G) / blue (B) data corresponding to one frame and obtaining a sum thereof; The average value is divided by dividing the sum of red (R) / green (G) / blue (B) data received from the adder by the number of pixels of red (R) / green (G) / blue (B) data corresponding to one frame. To obtain a lift; A comparator for comparing the average value received from the multiplier with the average value of all frames and outputting the difference value; And And a gamma lookup table for changing gamma of red (R), green (G), and blue (B) data for each frame according to the difference value received from the comparator. The method of claim 1, And the adder and the multiplier are configured to operate oppositely by a control signal (H_DE). The method of claim 1, And the adder operates in the enable period of the control signal and the divider operates in the disable period of the control signal. The method of claim 3, wherein The control signal is enabled when the first data enable signal DE of one frame is enabled, and is configured to be disabled when the last data enable signal DE is disabled. Circuit. In the driving circuit of the liquid crystal display device, First to third adders for receiving red (R) / green (G) / blue (B) data corresponding to one line and obtaining their sums; Pixels of red (R) / green (G) / blue (B) data corresponding to one line by adding the sum of red (R) / green (G) / blue (B) data received from the first to third adders First to third trimmers for dividing by the number to obtain an average value; First to third comparators for comparing the average value received from the first to third multipliers with an average value of line data of the previous frame and outputting a difference value; First to third multipliers for multiplying red (R) / green (G) / blue (B) data received from the first to third comparators by different constant values; A fourth adder that sums values received from the first to third multipliers; A fourth multiplier for dividing a value received from the fourth adder by 3 to determine a final gamma value corresponding to the line; A fourth comparator comparing the final gamma value received from the fourth multiplier with a final gamma value corresponding to a line of a previous frame and outputting a difference value; And And a gamma lookup table configured to change gamma of red (R), green (G), and blue (B) data for each line according to the difference value received from the fourth comparator. Circuit. The method of claim 5, And the first to third adders and the first to third multipliers are configured to operate in opposite directions by a control signal (H_DE), respectively. The method of claim 5, And the first to third adders operate in the enable period of the control signal, and the first to third multipliers operate in the disable period of the control signal. The method of claim 7, wherein The control signal is enabled when the first data enable signal DE of one line is enabled, and is configured to be disabled when the last data enable signal DE is disabled. Driving circuit. The method of claim 7, wherein And storing the average value received from the first to third multipliers and comparing the average value with the average value of data corresponding to the line of the next frame. In the driving method of a liquid crystal display device, Obtaining a sum of red (R) / green (G) / blue (B) data corresponding to one frame; Dividing the sum of the red (R) / green (G) / blue (B) data by the number of pixels of the red (R) / green (G) / blue (B) data corresponding to one frame to obtain an average value; Comparing the calculated average value with an average value of all frames and outputting a difference value; And And changing the gamma of the red (R), green (G), and blue (B) data for each frame based on the calculated difference value. In the driving method of a liquid crystal display device, Obtaining a sum of red (R), green (G), and blue (B) data corresponding to one line; Dividing the calculated sum of red (R) / green (G) / blue (B) data by the number of pixels of red (R) / green (G) / blue (B) data corresponding to one line to obtain an average value ; Comparing the average value of the calculated average value with the line data of the previous frame and outputting the difference value; Multiplying the calculated difference values of the red (R) / green (G) / blue (B) data by different constant values; Summing the calculated values; Dividing the calculated value by 3 to determine a final gamma value corresponding to the line; Comparing the final gamma value with a final gamma value corresponding to a line of a previous frame and outputting a difference value; And And changing the gamma of the red (R), green (G), and blue (B) data for each line based on the calculated difference value. By directly controlling the gamma table of the scalar used in the LCD monitor using the driving method of claim 11, the red (R) / green (G) / blue (B) line by line without changing the gamma reference voltage A method of driving a liquid crystal display device comprising changing data. By using the driving method of claim 11, the offset and gain of analog red (R) / green (G) / blue (B) data are controlled so that the red (R) / green (G) / blue ( B) A method of driving a liquid crystal display device, characterized by changing the gamma of data.

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