KR101308450B1 - Apparatus and method for driving liquid crystal display device - Google Patents

Abstract

The present invention relates to a driving device and a driving method of a liquid crystal display device to achieve a uniform luminance and to achieve a peak brightness between RGBW pixels.

A driving device of a liquid crystal display according to the present invention includes: a liquid crystal panel including a plurality of unit pixels including red, green, blue, and white subpixels; A data driver for supplying an image signal to each subpixel; A gate driver supplying a gate on voltage to the subpixels; A histogram is generated by using the gradation difference of the three-color input data supplied to the red, green, blue, and white subpixels, and using the color correction coefficients of the red, green, and blue colors, and the gain value extracted from the histogram. A data converter configured to convert the three-color input data into four-color data supplied to each of the red, green, blue, and white subpixels, and output the four-color data; And a timing controller for supplying the four-color data from the data converter to the data driver and controlling the gate driver and the data driver.

RGBW, gain value, histogram, gradation loss, color difference

Description

TECHNICAL FIELD [0001] The present invention relates to a driving apparatus and a driving method for a liquid crystal display device,

1 is a block diagram illustrating a driving device of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a block diagram illustrating a data converter shown in FIG. 1. FIG.

3 is a block diagram schematically showing a histogram generator shown in FIG.

4 is a block diagram schematically illustrating an RGBW generator according to a first embodiment of the present invention shown in FIG. 2.

5 is a view showing an image displayed by the driving device and driving method of the liquid crystal display according to the embodiment of the present invention.

6 is a view showing another image displayed by the driving apparatus and driving method of the liquid crystal display according to the embodiment of the present invention.

FIG. 7 is a block diagram schematically illustrating an RGBW generator according to a second embodiment of the present invention shown in FIG. 2.

FIG. 8 is a graph for setting color correction coefficients of red, green, and blue in the color correction coefficient setting unit shown in FIG.

9 is a view showing an image displayed by the driving device and driving method of the liquid crystal display according to another embodiment of the present invention.

10 is a view showing another image displayed by the driving device and driving method of the liquid crystal display according to another embodiment of the present invention.

Description of the Related Art [0002]

102: liquid crystal panel 104: data driver

106: gate driver 108: timing controller

110: data conversion unit 200: first gamma correction unit

210: gray level detection unit 220: histogram generation unit

230: gain value extraction unit 240: RGBW generation unit

250: second gamma correction unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a driving device and a driving method of a liquid crystal display device which can realize a peak brightness while achieving a uniform color difference between RGBW pixels.

Recently, various flat panel display devices that can reduce weight and volume, which are disadvantages of cathode ray tubes, have emerged. Such flat panel displays include a liquid crystal display, a field emission display, a plasma display panel, a light emitting display, and the like.

Among flat panel displays, a liquid crystal display includes a plurality of liquid crystal cells disposed in a region defined by a plurality of data lines and a plurality of gate lines, and a thin film transistor (TFT) as a switch element in each liquid crystal cell. And a color filter substrate on which a color filter is formed are maintained at regular intervals and includes a liquid crystal layer formed therebetween.

Such a liquid crystal display obtains a desired image by forming an electric field in the liquid crystal layer in accordance with the data signal to adjust the transmittance of light passing through the liquid crystal layer. In this case, the polarity of the data signal is reversed on a frame, row, or dot basis in order to prevent deterioration caused by an electric field applied to the liquid crystal layer for a long time.

Such a liquid crystal display device realizes one color image by mixing red light, green light, and blue light from three color dots of red (R), green (G), and blue (B). However, there is a disadvantage in that light efficiency is lowered in a general liquid crystal display device that displays one subpixel with three color dots of red (R), green (G), and blue (B). Specifically, the color filter disposed in each of the red, green, and blue subpixels transmits only about one third of the applied light, thereby reducing the overall light efficiency.

Accordingly, RGBW including white subpixels (W) in addition to the red (R), green (G), and blue (B) subpixels as a method for improving luminance and light efficiency while maintaining color reproducibility of the liquid crystal display device. A type liquid crystal display device has been proposed.

The RGBW type liquid crystal display multiplies each of the three-color input data by a gain value to generate three-color amplified data, and then extracts data having the minimum gray scale among the three-color amplified data as white data, and then extracts the three-color amplified data from the three-color amplified data. Four color data is generated by subtracting the extracted white data.

However, in the conventional method of converting three-color data to four-color data, when a part of an image of one frame is pure color of high saturation / brightness, the luminance of other regions is also darkened to express peak luminance, which is an advantage of the RGBW type liquid crystal display. There is a disadvantage that can not be.

In the conventional RGBW type liquid crystal display, when a full white image is displayed, a full white image displayed through three color subpixels and a full white image displayed through white subpixels W are different. That is, even if the white balance of each of the three color subpixels is matched, there is a problem that a color difference occurs between the image by the three color subpixels and the image by the white subpixel W due to the material characteristics of the color filter.

Accordingly, in order to solve the above problems, the present invention is to provide a driving apparatus and a driving method of the liquid crystal display device to achieve a uniform luminance and to achieve a peak brightness between the RGBW pixels.

According to an aspect of the present invention, there is provided a driving apparatus of a liquid crystal display device including: a liquid crystal panel including a plurality of unit pixels including red, green, blue, and white subpixels; A data driver for supplying an image signal to each subpixel; A gate driver supplying a gate on voltage to the subpixels; A histogram is generated by using the gradation difference of the three-color input data supplied to the red, green, blue, and white subpixels, and using the color correction coefficients of the red, green, and blue colors, and the gain value extracted from the histogram. A data converter configured to convert the three-color input data into four-color data supplied to each of the red, green, blue, and white subpixels, and output the four-color data; And a timing controller for supplying the four-color data from the data converter to the data driver and controlling the gate driver and the data driver.

A driving method of a liquid crystal display according to an exemplary embodiment of the present invention is a driving method of a liquid crystal display including a plurality of unit pixels including red, green, blue, and white subpixels, and the gray level difference of input three-color input data is different. A first step of generating a histogram and extracting a gain value from the histogram, and a second step of converting the three-color input data into four-color data using the red, green, and blue color correction coefficients and the gain value. And a third step of converting each of the four color data into the image signal and supplying each of the red, green, blue, and white subpixels.

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

1 is a view schematically illustrating a driving device of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a driving apparatus of a liquid crystal display according to an exemplary embodiment of the present invention may include every four subpixel regions defined by n gate lines GL1 through GLn and m data lines DL1 through DLm. A liquid crystal panel 102 including a formed liquid crystal cell; A data driver 104 for supplying an image signal to the data lines DL1 to DLm; A gate driver 106 for supplying a gate-on voltage to the gate lines GL1 through GLn; A histogram is generated using the gradation difference of the input tri-color input data (RGB), and the tri-color input data (RGB) is converted into four-color data (RGBW) using the color correction coefficient and the gain extracted from the histogram. The data converter 110 converts and outputs the data, and the four-color data RGBW from the data converter 110 is aligned and supplied to the data driver 104 to generate a data control signal DCS. The timing controller 108 controls the gate driver 106 by controlling the gate 104 and generating a gate control signal GCS.

The liquid crystal panel 102 includes a thin film transistor TFT formed in a region defined by n gate lines GL1 through GLn and m data lines DL1 through DLm, and liquid crystal cells connected to the thin film transistor TFT. Equipped. The thin film transistor TFT supplies a data signal from the data lines DL1 to DLm to the liquid crystal cell in response to the gate-on voltages from the gate lines GL1 to GLn. The liquid crystal cell is composed of a common electrode facing each other with a liquid crystal interposed therebetween, and a subpixel electrode connected to the thin film transistor TFT. The liquid crystal cell includes a storage capacitor Cst to maintain the data signal charged in the liquid crystal capacitor Clc until the next data signal is charged.

Meanwhile, in the liquid crystal panel 102, red (R), green (G), blue (B), and white (W) subpixels are repeatedly formed in the row direction of the subpixels. Each of the red (R), green (G), and blue (B) subpixels is disposed with a color filter corresponding to each color, whereas a separate color filter is not disposed with the white (W) subpixel. In addition, the red (R), green (G), blue (B), and white (W) subpixels form a stripe structure having the same area ratio or different area ratios. In this case, the red (R), green (G), blue (B), and white (W) subpixels may be arranged in a vertical, horizontal, left, right, 2 × 2 matrix form.

The data converter 110 uses the gray level difference of the three-color input data RGB supplied to each of the unit pixels consisting of subpixels of red (R), green (G), and blue (B) input from the outside. Extract the histogram for each gradation difference, convert the three-color input data (RGB) into four-color data (RGBW) and supply it to the timing controller 108 by using the gain value and color correction coefficient extracted from the extracted gradation histogram. do.

The timing controller 108 arranges the four-color data RGBW supplied from the data converter 110 to be suitable for driving the liquid crystal panel 102 and supplies the four color data RGBW to the data driver 104. In addition, the timing controller 108 uses the main clock MCLK, the data enable signal DE, and the horizontal and vertical synchronization signals Hsync and Vsync, which are input from the outside, to control the data control signal DCS and the gate control signal ( GCS) is generated to control driving timing of each of the data driver 104 and the gate driver 106.

The gate driver 106 sequentially generates a gate-on voltage, that is, a gate high pulse, in response to the gate start pulse GSP and the gate shift clock GSC of the gate control signal GCS from the timing controller 108. Contains shift registers. The thin film transistor TFT is turned on in response to the gate-on voltage.

The data driver 104 converts the four-color data Data arranged from the timing controller 108 into an image signal, which is an analog signal, in accordance with the data control signal DCS supplied from the timing controller 108, to gate lines GL1. To GLn) is supplied with one horizontal line of image signals to the data lines DL1 to DLm every one horizontal period to which the gate-on voltage is supplied. That is, the data driver 104 selects a gamma voltage having a predetermined level according to the gray value of the four-color data Data, and supplies the selected gamma voltage to the data lines DL1 to DLm.

2 is a block diagram illustrating a data converter 110 according to an exemplary embodiment of the present invention shown in FIG. 1.

Referring to FIG. 2, the data converter 110 may include a first gamma correction unit 200, a gray scale detector 210, a histogram generator 220, a gain value extractor 230, and an RGBW generator ( 240 and a second gamma correction unit 250.

The first gamma correction unit 200 is linearized by using the following Equation 1 since the three-color input data RGB of each unit pixel of the input image is gamma corrected in consideration of the output characteristics of the cathode ray tube. Correction is performed using the difference three-color data (RI, GI, BI).

The gray scale detection unit 210 compares the primary three-color data (RI, GI, BI) of each unit pixel supplied from the first gamma correction unit 200 to each other and the maximum gray value (MAX _RGB ) and the minimum gray scale for each unit pixel. Detect the value (MIN _RGB ). The gray level detector 210 supplies the detected maximum gray value MAX _RGB and the minimum gray value MIN _RGB to the histogram generator 220.

As shown in FIG. 3, the histogram generator 220 includes a first subtractor 222, a histogram calculator 224, and a histogram accumulator 226.

The first subtraction unit 222 subtracts the minimum gray value MIN _RGB from the maximum gray value MAX _RGB for each unit pixel supplied from the gray level detector 210, thereby adjusting the gray level difference per unit pixel (MAX _{RGB to} MIN _RGB ). Obtain Here, the gray level difference (MAX _RGB- MIN _RGB ) for each unit pixel is an element that determines the saturation saturation of the pixel when the three-color input data _{RGB is} converted into the four-color data RGBW.

The histogram calculator 224 calculates a histogram Hist_s for each gray level difference by counting the number of pixels for each gray level difference (MAX _{RGB to} MIN _RGB ) for each unit pixel supplied from the first subtractor 222.

The histogram accumulator 226 accumulates the histogram Hist_s for each gray level difference from the histogram calculator 224 for each gray level difference, and calculates a cumulative histogram Hist_c for each gray level difference. It is supplied to the gain value extraction unit 230.

As such, the histogram generator 220 has been proposed by Korean Patent Application No. 10-2005-0126274 filed by the present applicant.

In FIG. 2, the gain value extracting unit 230 accumulates the gray level difference at the time when the gray level histogram Hist_c, which is supplied from the histogram accumulator 226, exceeds the gray level setting value M input from the user. A gain value k is extracted according to Equation 2 below using the histogram-level gradation loss limit value N. At this time, the gain value k has a range of 1 to 2.

The gain value extractor 220 supplies the extracted gain value k to the RGBW generator 240.

In Equation 2, MAX _gray represents a maximum gray value corresponding to the number of bits of the input data RGB, and becomes '255' when the input data RGB is 8 bits. In order to prevent the denominator from being zero in Equation 2, one gray scale is added to the gray scale loss limit value N.

The saturation saturation setting value M set by the user is a variable for setting the number of saturation allowable pixels of the pixels displayed on the liquid crystal panel 102. The saturation saturation setting value M may be set to '0', '3000', '6000', '10000', etc. according to the user's preference according to the resolution of the liquid crystal panel 102. The saturation saturation setting value M refers to the number of pixels which do not affect visual quality visually even when saturation occurs when generating the four-color data RGBW. For example, the gain value extracting unit 230 has a saturation setting value M of '10000', and a cumulative value of the histogram Hist_s of each gradation difference in the cumulative histogram Hist_c for each gradation difference exceeds 10000. When the maximum and minimum gradation difference (MAX _RGB -MIN _RGB ) is' 135 ', set' 135 'to the gradation loss limit value (N), and add' 1 'to the gradation loss limit value (N) to' Divide 255 'and' 136 'to generate a gain value (k) with' 1.875 '.

As shown in FIG. 4, the RGBW generator 240 according to the first embodiment of the present invention includes a multiplier 310, a color corrector 320, a white data extractor 330, and a second subtractor 340. It is configured to include).

The multiplier 310 uses the first three-color data (RI, GI, BI) supplied from the first gamma corrector 200 and the gain value k supplied from the gain value extractor 230 to determine the following. As shown in Equation 3, secondary tricolor data Ra, Ga, and Ba are generated. That is, the multiplication unit 310 multiplies the gain value k by each of the primary tricolor data RI, GI, and BI to generate the secondary tricolor data Ra, Ga, and Ba.

Ra = RI × k

Ga = GI × k

Ba = BI × k

Color The correction unit 320  According to the color correction coefficients (αr, αg, αb) of each of red (R), green (G) and blue (B) supplied from the outside From multiplication unit 310  Secondary tricolor data supplied ( Ra, Ga, Ba) Calibrated  Tertiary tricolor data ( Rb , Gb , Bb).

Here, the color correction coefficients αr, αg, and αb of each of red (R), green (G), and blue (B) are white. Of subpixel (W)  It is set according to a characteristic and is white Subpixel (W)  The spectral density of the white light that passes through each of the red (R), green (G), and blue (B) On the subpixel  Is set equal to the spectral density of the white light. That is, white (W) Subpixel  When the luminance increases by '1', the red (R), green (G) and blue (B) Subpixel  Each color should be reduced by '1' to make 3 colors (R, G, B) On the subpixel  Color and white (W) On the subpixel  Color becomes the same. In this case, each of the red (R), green (G), and blue (B) colors may have different values of the color correction coefficients αr, αg, and αb.

Therefore, color The correction unit 320  bracket Of subpixels (R, G, B, W)  Red (R) and Green (G) depending on the characteristics Subpixel  When each of the color correction coefficients αr and αg is '0.95' and the subpixel color correction coefficient αb of blue (B) is set to 1.1, the secondary red (R) and green (G) data (Ra) , Ga) and the second blue (B) data ( Ba ) By "1.1" to reduce the third color data ( Rb , Gb , Bb).

The white data extractor 330 extracts data having a minimum gray level among the third tertiary color data Rb, Gb, and Bb supplied from the color corrector 320 as the white data Wb.

The second subtracting unit 340 may receive the white data supplied from the white data extracting unit 330 in each of the secondary tricolor data Ra, Ga, and Ba supplied from the multiplier 310 as shown in Equation 4 below. Subtract Wb) to generate quaternary tricolor data (Rc, Gc, Bc), and quaternary tricolor data (Rc, Gc, Bc) and white data (Wb) are converted into four-color conversion data (Rc, Gc, Bc). , Wc) to be supplied to the second gamma correction unit 250.

Rc = Rb-Wb

Gc = Gb-Wb

Bc = Bb-Wb

Wc = Wb

In FIG. 3, the second gamma correction unit 250 gamma-corrects the four-color conversion data Rc, Gc, Bc, and Wc supplied from the RGBW generation unit 240 as shown in Equation 5 below to display four-color data ( RGBW). In this case, the second gamma correction unit 250 uses the look up table (not shown) to convert the four-color conversion data Rc, Gc, Bc, and Wc into four colors suitable for the driving circuit of the liquid crystal panel 102. Gamma correction is performed on the data RGBW and supplied to the timing controller 108.

The driving apparatus and driving method of the liquid crystal display according to the exemplary embodiment of the present invention include three-color sub by performing color correction on the three-color data RI, GI, and BI according to the three-color color correction coefficients αr, αg, and αb. The color of the pixel and the white subpixel can be the same.

In addition, in the driving apparatus and driving method of the liquid crystal display according to the exemplary embodiment of the present invention, it is possible to know how many pixels in the image are to be saturated by the saturation saturation setting value M set by the user. Therefore, the luminance of the liquid crystal panel 102 having the subpixels of RGBW can be kept bright while generating grayscale saturation below a level that can be perceived visually by a person.

That is, even if gray scale saturation occurs in a small area of the displayed image on the liquid crystal panel 102, it is difficult to visually recognize. Therefore, setting a high gain value k even in consideration of some partial gray scale loss may improve brightness and image quality. More advantageous. For example, when the saturation setting value M is set to 10000, 10000 pixels correspond to an area of 0.95% on the liquid crystal panel 102 having a resolution of 1366 × 768 and thus do not affect image quality deterioration visually. .

As described above, in the driving apparatus and driving method of the liquid crystal display according to the exemplary embodiment of the present invention, even in an image having a small gain value k for an image of one frame as compared to the original image, there is a slight loss. It provides a higher image quality but provides higher luminance than the original image, and at the same time, implements peak luminance in the high brightness / achromatic portion.

In addition, the driving apparatus and driving method of the liquid crystal display according to the embodiment of the present invention provide the same image quality and luminance as the original image even in an image having a large gain value k for an image of one frame as shown in FIG. 6. Done.

7 is a block diagram schematically illustrating an RGBW generator according to a second embodiment of the present invention.

Referring to FIG. 7, the RGBW generator 240 according to the second embodiment of the present invention includes a multiplier 310, a color correction coefficient setting unit 410, a color correction unit 420, and a white data extraction unit 330. ) And a second subtraction unit 340.

The multiplication unit 310 multiplies the gain value k by each of the primary three-color data RI, GI, and BI as shown in Equation 3 to generate the secondary three-color data Ra, Ga, Ba. do.

The color correction coefficient setting unit 410 maintains the set ratio of the three color reference color correction coefficients Ref_αr, Ref_αg, and Ref_αb, and adjusts the red, green, and blue colors according to the gain value k. Color correction coefficients alpha r, alpha g, and alpha b are set in units of frames.

Specifically, the color correction coefficient setting unit 410 maintains the ratio of the reference color correction coefficients Ref_αr, Ref_αg, and Ref_αb of red (R), green (G), and blue (B) set as shown in FIG. 8. While setting the upper and lower color correction coefficients (αr_max, αg_max, αb_max) and the lower color correction coefficients (αr_min, αg_min, αb_min) of red (R), green (G) and blue (B), the following equations 6 to 8 Gain values using a linear equation between the upper limit color correction coefficients (αr_max, αg_max, αb_max) and the lower limit color correction coefficients (αr_min, αg_min, αb_min) of red (R), green (G) and blue (B) Color correction factors αr, αg, and αb of red (R), green (G), and blue (B) corresponding to (k) are generated. At this time, the color correction coefficient setting unit 410 sets the lower limit color correction coefficients αr_min, αg_min, and αb_min of red (R), green (G), and blue (B) to red (R), green (G), and blue ( The upper limit color correction coefficients (αr_max, αg_max, αb_max) of B) can be set in the range of 60% to 90%. In addition, the color correction coefficient setting unit 410 has a lower color correction coefficient αr_min of red (R), green (G), and blue (B) when the gain value k has a minimum value k_min of '1'. , αg_min, αb_min) are set to red (R), green (G), and blue (B) color correction coefficients (αr, αg, αb), and '2' whose gain value (k) is the maximum value (k_max). When the upper limit color correction coefficients (αr_max, αg_max, αb_max) of red (R), green (G) and blue (B), the color correction coefficient (αr of red (R), green (G) and blue (B) , αg, αb).

For example, when the reference color correction coefficients (Ref_αr, Ref_αg) of red (R) and green (G) are '0.95', and the reference color correction coefficient (Ref_αb) of blue (B) is set to '1.1' The coefficient setting unit 410 stores the reference color correction coefficients Ref_αr, Ref_αg, and Ref_αb of red (R), green (G), and blue (B), respectively, of red (R), green (G), and blue (B). The upper limit color correction coefficients (αr_max, αg_max, αb_max) are set, and the ratio of each of the reference color correction coefficients (Ref_αr, Ref_αg, Ref_αb) of red (R), green (G) and blue (B) is reduced to remain as it is. The lower color correction coefficients αr_min and αg_min of red (R) and green (G) are set to '0.65', and the lower color correction coefficients (αb_min) of blue (B) are set to '0.749'.

When the gain value (k) is between the minimum value (k_min) and the maximum value (k_max), the color correction coefficients (αr, αg, αb) of red (R), green (G), and blue (B) are red (R). , The upper limit color correction coefficients? R_max,? G_max,? B_max, and the lower limit color correction coefficients? R_min,? G_min,? B_min of green (G) and blue (B). For example, when the gain value k is 1.5, the color correction coefficient setting unit 410 determines the color correction coefficients αr and αg of red (R) and green (G) according to equations (6) and (7). In addition, the color correction coefficient? B of the blue color B is set to '0.9245' by Equation (8). As another example, when the gain value k is 1.9, the color correction coefficient setting unit 410 determines the color correction coefficients αr and αg of red (R) and green (G) by using Equations 6 and 7. In addition, the color correction coefficient αb of the blue color B is set to 1.0649 by Equation 8.

In FIG. 7, the color correcting unit 420 multiplies the color correcting coefficients αr, αg, and αb of red (R), green (G), and blue (B) supplied from the color correction coefficient setting unit 410. Secondary tricolor data (Ra, Ga, Ba) supplied from the unit 310 is corrected to generate tertiary tricolor data (Rb, Gb, Bb). Since the color corrector 420 is the same as the color corrector 320 of FIG. 4, the detailed description will be replaced with the above description.

The white data extracting unit 330 extracts data having the minimum gray scale among the third tri-color data Rb, Gb, and Bb supplied from the color correcting unit 320 as white data Wb, as described in FIG. 4. do.

The second subtractor 340 generates four color conversion data Rc, Gc, Bc, and Wc according to Equation 4, and supplies it to the second gamma corrector 250.

The RGBW generator 240 according to the second exemplary embodiment of the present invention uses the color correction coefficients αr, αg, and αb of red (R), green (G), and blue (B) as gain values (k) in units of frames. Adjust according to). That is, when the gain value (k) is low, the value is decreased while maintaining the ratio of the color correction coefficients (αr, αg, αb) of red (R), green (G), and blue (B) to maintain color. When the gain value (k) is high, the value is measured in the original measured red (R), green while maintaining the ratio of the color correction coefficients (αr, αg, αb) of red (R), green (G), and blue (B). The reference color correction coefficients (Ref_? R, Ref_? G, and Ref_? B) of (G) and blue (B) are increased to be closer to each other.

Accordingly, the RGBW generator 240 according to the second embodiment of the present invention may have a slightly lost image quality compared to the original image even when the gain value k for the image of one frame is small as shown in FIG. 9. However, it provides higher luminance than the original image and at the same time achieves peak luminance in the high brightness / achromatic portion.

In addition, the RGBW generator 240 according to the second embodiment of the present invention has a high luminance due to the large gain value k even in an image having a large gain value k for an image of one frame as shown in FIG. 10. In addition to providing the same image quality as the original image.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

The driving apparatus and driving method of the liquid crystal display according to the exemplary embodiment of the present invention as described above use the histogram analyzed based on the difference between the maximum and minimum gray levels of the input data, and the gray level below the gray level setting value set by the user. The gain value is extracted to generate a loss, and the tri-color data is converted into 4-color data by using the extracted gain value and color correction coefficient. Accordingly, the present invention can realize the peak luminance while making the color difference between the red, green, blue, and white subpixels uniform. In addition, the present invention may brighten the luminance of the achromatic region even if the gain value of the frame is low.

Claims (36)

A liquid crystal panel including a plurality of unit pixels including red, green, blue, and white subpixels; A data driver for supplying an image signal to each subpixel; A gate driver supplying a gate on voltage to the subpixels; A histogram is generated by using the gradation difference of the three-color input data supplied to the red, green, blue, and white subpixels, and using the color correction coefficients of the red, green, and blue colors, and the gain value extracted from the histogram. A data converter configured to convert the three-color input data into four-color data supplied to each of the red, green, blue, and white subpixels, and output the four-color data; A timing controller for supplying the four-color data from the data converter to the data driver and controlling the gate driver and the data driver; The data converter generates the gain value on a frame-by-frame basis using the histogram and a gray scale setting value set by a user; The gray saturation setting value is a driving device of the liquid crystal display device, characterized in that the number of pixels saturation occurs among a plurality of unit pixels. delete delete The method of claim 1, Wherein the data conversion unit comprises: A first gamma correction unit configured to gamma correct the three-color input data to generate linearized primary three-color data; A gray scale detector for detecting a maximum and minimum gray scale value for each unit pixel of the primary tricolor data; A histogram generator for generating the histogram by using a gray level difference between the maximum and minimum gray values; A gain value extracting unit extracting the gain value using the histogram and the gray scale saturation setting value; An RGBW generation unit for converting the primary three-color data into four-color converted data using the gain value and the color correction coefficients of the red, green, and blue colors; And a second gamma correction unit configured to gamma correct the four color conversion data to generate the four color data. 5. The method of claim 4, The gain value is set in the range of 1 to 2 drive device of the liquid crystal display device. 6. The method of claim 5, The histogram generator, A first subtractor configured to subtract the minimum gray value from the maximum gray value to generate a gray level difference between the maximum and minimum gray values; A histogram calculator for calculating a histogram for each gray level difference by counting the number of unit pixels corresponding to the gray level difference between the maximum and minimum gray values from the first subtractor; And a histogram accumulator configured to accumulate the histograms for each gray level difference and generate a cumulative histogram for each gray level difference. The method of claim 6, And the histogram accumulator accumulates from the histogram for each gray level difference with the largest gray level toward the histogram for each gray level with the smallest gray level difference. The method of claim 6, The gain value extracting unit generates the gain value by using a gradation loss limit value which is a time point exceeding the gradation saturation setting value in the cumulative histogram for each gradation difference and a total gradation number corresponding to the number of bits of the input data. A drive device for a liquid crystal display device. 9. The method of claim 8, And the gain value extracting unit divides the total number of gradations by adding 1 to the gradation loss limit value. 6. The method of claim 5, The RGBW generation unit, A multiplier for multiplying the primary tricolor data and the gain value to generate secondary tricolor data; A color correcting unit configured to correct the second tricolor data according to the red, green, and blue color correction coefficients to generate third tricolor data; A white data extracting unit extracting data having a minimum gray level among the third three-color data as white data; Generating fourth fourth color data by subtracting the white data from each of the second third color data, and supplying the fourth color conversion data having the fourth third color data and the white data to the second gamma correction unit. A drive device for a liquid crystal display device comprising two subtracting parts. 6. The method of claim 5, The RGBW generation unit, A multiplier for multiplying the primary tricolor data and the gain value to generate secondary tricolor data; A color correction coefficient setting unit for setting the color correction coefficients of the red, green, and blue colors according to the gain value in units of frames; A color correcting unit configured to correct the second tricolor data according to the red, green, and blue color correction coefficients set by the color correction coefficient setting unit to generate tertiary tricolor data; A white data extracting unit extracting data having a minimum gray level among the third three-color data as white data; Generating fourth fourth color data by subtracting the white data from each of the second third color data, and supplying the fourth color conversion data having the fourth third color data and the white data to the second gamma correction unit. A drive device for a liquid crystal display device comprising two subtracting parts. The method of claim 11, The color correction coefficient setting unit sets the upper and lower color correction coefficients of the red, green, and blue colors using the red, green, and blue reference color correction coefficients having fixed values, respectively, and the red, green, and blue colors. And the red, green, and blue color correction coefficients corresponding to the gain values are set using a linear equation between the blue upper limit color correction coefficient and the lower limit color correction coefficient. 13. The method of claim 12, Each of the upper and lower color correction coefficients of the red, green, and blue colors is set as the reference color correction coefficients of the red, green, and blue colors. And the lower limit color correction coefficients of the red, green, and blue colors are set in a range of 60% to 90% of the upper limit color correction coefficients of the red, green, and blue colors. 14. The method of claim 13, And the upper and lower color correction coefficients of the red, green, and blue colors maintain the ratios of the reference color correction coefficients of the red, green, and blue colors, respectively. 14. The method of claim 13, The color correction coefficient setting unit, When the gain value is a minimum value, each of the lower limit color correction coefficients of the red, green, and blue colors is set as the color correction coefficients of the red, green, and blue colors, When the gain value is the maximum value, each of the upper and lower color correction coefficients of the red, green, and blue colors is set as the color correction coefficients of the red, green, and blue colors, And the linear value corresponding to the gain value is set to the red, green, and blue color correction coefficients when the gain value is between the minimum value and the maximum value. The method according to claim 10 or 11, And the color correction coefficients of the red, green, and blue colors reduce the data supplied to each of the red, green, and blue subpixels at a predetermined ratio. 17. The method of claim 16, And the color correction coefficients of the red, green, and blue colors are set to have different values. 18. The method of claim 17, And the color correction coefficients of the red and the green are set to the same value. A driving method of a liquid crystal display device comprising a plurality of unit pixels consisting of red, green, blue, and white subpixels, A first step of generating a histogram using the gray level difference of the input three-color input data and extracting a gain value from the histogram; A second step of converting the three-color input data into four-color data using red, green, and blue color correction coefficients and the gain value; Converting each of the four color data into an image signal and supplying each of the red, green, blue, and white subpixels; The extracting of the gain value may include generating the gain value in units of frames by using the histogram and a gray scale setting value set by a user; And the gray level setting value is a number of pixels in which gray level saturation occurs among a plurality of unit pixels. delete delete 20. The method of claim 19, In the first step, Gamma correcting the tricolor input data to generate linearized primary tricolor data; Detecting a maximum and minimum gray level value for each unit pixel of the primary tricolor data; Generating the histogram using gray level differences between the maximum and minimum gray values; And extracting the gain value using the histogram and the saturation saturation setting value. 23. The method of claim 22, The gain value is set in the range of 1 to 2, the driving method of the liquid crystal display device. 24. The method of claim 23, Generating the histogram, Subtracting the minimum gray value from the maximum gray value to generate a gray level difference between the maximum and minimum gray values; Calculating a histogram for each gradation difference by counting the number of unit pixels corresponding to the gradation difference between the maximum and minimum gradation values; And accumulating the histograms for each gray level difference to generate a cumulative histogram for each gray level difference. 25. The method of claim 24, The generating of the cumulative histogram may include accumulating from the histogram for each gray level difference with the largest gray level toward the histogram for the gray level difference with the smallest gray level difference. 25. The method of claim 24, The extracting of the gain value may include generating the gain value by using a gradation loss limit value that is a time point exceeding the gradation saturation setting value in the cumulative histogram for each gradation difference and a total gradation number corresponding to the number of bits of the input data. A method of driving a liquid crystal display device, characterized in that. 27. The method of claim 26, And the gain value is a result of a division operation of dividing the total gray number by adding 1 to the gray scale loss limit value. 24. The method of claim 23, The second step, Generating a second tricolor data by multiplying the first tricolor data and the gain value; Generating third tertiary color data by correcting the second tertiary color data according to the red, green, and blue color correction coefficients; Extracting data having a minimum gray scale among the third tricolor data as white data; Generating fourth fourth color data by subtracting the white data from each of the second third color data; And gamma correcting the quaternary tricolor data and the white data to generate the four-color data. 24. The method of claim 23, The second step, Generating a second tricolor data by multiplying the first tricolor data and the gain value; A color correction coefficient setting unit for setting the color correction coefficients of the red, green, and blue colors according to the gain value in units of frames; Generating third tertiary color data by correcting the secondary tricolor data according to the red, green, and blue color correction coefficients set by the color correction coefficient setting unit; Extracting data having a minimum gray scale among the third tricolor data as white data; Generating fourth fourth color data by subtracting the white data from each of the second third color data; And gamma correcting the quaternary tricolor data and the white data to generate the four-color data. 20. The method of claim 19, The setting of the red, green, and blue color correction coefficients may include setting upper and lower color correction coefficients of red, green, and blue colors using reference color correction coefficients of red, green, and blue having fixed values. And setting the color correction coefficients of the red, green, and blue colors corresponding to the gain values using a linear equation between the upper and lower color correction coefficients of the red, green, and blue colors. Method of driving display device. 31. The method of claim 30, Each of the upper and lower color correction coefficients of the red, green, and blue colors is set as the reference color correction coefficients of the red, green, and blue colors. And the lower limit color correction coefficients of the red, green, and blue colors are set in a range of 60% to 90% of the upper limit color correction coefficients of the red, green, and blue colors. 32. The method of claim 31, And the upper and lower color correction coefficients of the red, green, and blue colors maintain the ratios of the reference color correction coefficients of the red, green, and blue colors, respectively. 32. The method of claim 31, The setting of the red, green, and blue color correction coefficients may include: When the gain value is a minimum value, each of the lower limit color correction coefficients of the red, green, and blue colors is set as the color correction coefficients of the red, green, and blue colors, When the gain value is the maximum value, each of the upper and lower color correction coefficients of the red, green, and blue colors is set as the color correction coefficients of the red, green, and blue colors, And when the gain value is between the minimum value and the maximum value, setting the linear value corresponding to the gain value to the color correction coefficients of the red, green, and blue colors. 30. The method of claim 28 or 29, And the color correction coefficients of the red, green, and blue colors reduce data supplied to each of the red, green, and blue subpixels at a predetermined ratio. 35. The method of claim 34, And the color correction coefficients of the red, green, and blue colors are set to have different values. 36. The method of claim 35, The red and green color correction coefficients are set to the same value.

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