KR101174782B1 - Apparatus and Method for Driving Liquid Crystal Display Device - Google Patents

Apparatus and Method for Driving Liquid Crystal Display Device Download PDF

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KR101174782B1
KR101174782B1 KR1020050058622A KR20050058622A KR101174782B1 KR 101174782 B1 KR101174782 B1 KR 101174782B1 KR 1020050058622 A KR1020050058622 A KR 1020050058622A KR 20050058622 A KR20050058622 A KR 20050058622A KR 101174782 B1 KR101174782 B1 KR 101174782B1
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South Korea
Prior art keywords
histogram
step
average value
value
data
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KR1020050058622A
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Korean (ko)
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KR20070002920A (en
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손민호
김성균
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엘지디스플레이 주식회사
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Priority to KR1020050058622A priority Critical patent/KR101174782B1/en
Priority claimed from US11/415,747 external-priority patent/US7609244B2/en
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Abstract

The present invention relates to a driving device and a driving method of a liquid crystal display device which can change the brightness of a display image according to input data and improve contrast.
A driving device of a liquid crystal display according to the present invention includes a liquid crystal panel for displaying an image corresponding to a data signal; A data driver for supplying the data signal to the liquid crystal panel; A gate driver for supplying a scan signal to the liquid crystal panel; Obtaining a histogram by dividing the luminance components of the input first data into a plurality of stages, generating second data having an expanded contrast ratio corresponding to the luminance of the histogram for each stage using an average value of the histogram, and at least according to the average value of the histogram. An image quality improving unit generating one brightness control signal; A timing controller for rearranging the second data to supply the data driver and controlling the data driver and the gate driver; A backlight for irradiating light onto the liquid crystal panel; And an inverter for driving the backlight according to the brightness control signal.
Contrast, histogram, average value, luminance component, slope

Description

Driving apparatus and driving method of liquid crystal display device {Apparatus and Method for Driving Liquid Crystal Display Device}

1 is a block diagram schematically showing a driving device of a conventional liquid crystal display.

2 is a block diagram illustrating a driving device of a liquid crystal display according to a first embodiment of the present invention.

3 is a block diagram illustrating an image quality improvement unit illustrated in FIG. 2.

4 is a block diagram illustrating a histogram analyzer according to the first exemplary embodiment of the present invention shown in FIG. 3.

5 is a diagram illustrating a step-by-step histogram generated by the histogram generator shown in FIG. 4.

6 is a diagram illustrating a stepped histogram modulated by the histogram modulator shown in FIG. 4.

7 is a diagram illustrating modulation luminance components modulated by the histogram modulator shown in FIG. 4; FIG.

FIG. 8 is a diagram illustrating an image contrasted by a histogram analyzer according to a first embodiment of the present invention with a conventional image; FIG.

9 is a block diagram illustrating a histogram analyzer according to a second exemplary embodiment of the present invention shown in FIG. 3.

FIG. 10 is a diagram illustrating a step-by-step histogram generated by the histogram generator illustrated in FIG. 9.

FIG. 11 is a diagram illustrating a stepped histogram modulated by the histogram modulator shown in FIG. 9. FIG.

FIG. 12 is a diagram illustrating modulation luminance components modulated by the histogram modulator shown in FIG. 9; FIG.

FIG. 13 is a diagram illustrating an image contrasted by a histogram analyzer according to a second exemplary embodiment of the present invention with a conventional image. FIG.

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

FIG. 15 is a block diagram illustrating an image quality improvement unit illustrated in FIG. 14.

<Explanation of Signs of Major Parts of Drawings>

2, 22: liquid crystal panel 4, 24: data driver

6, 26: gate driver 8, 28: gamma voltage supply

10, 30: timing controller 12, 32: power supply

14, 34: DC / DC converter 16, 36, 82: inverter

18, 38, 84: backlight 20, 40: system

42, 80: image quality improvement unit 50: luminance / color separation unit

52: delay unit 54: luminance / color mixing unit

56, 90: histogram analyzer 58: histogram modulator

70: video signal modulation means 72, 92: backlight control means

150: histogram generator 152: average value generator

154: frequency generator 156: step weight setting unit

157: minimum inclination setting unit 158: step inclination setting 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 for changing the brightness of a display image according to input data and improving contrast.

The liquid crystal display displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. The liquid crystal display is implemented in an active matrix type in which switching elements are formed in each cell, and thus, the liquid crystal display is applied to display devices such as computer monitors, office equipment, and cellular phones. 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.

1 is a block diagram schematically illustrating a driving device of a liquid crystal display according to the related art.

Referring to FIG. 1, a driving apparatus of a liquid crystal display according to the related art has m × n liquid crystal cells Clc arranged in a matrix type, m data lines DL1 through DLm and n gate lines GL1 through. A liquid crystal panel 2 having GLn intersected and a TFT formed at an intersection thereof, a data driver 4 for supplying a data signal to the data lines DL1 to DLm of the liquid crystal panel 2, and gate lines. The gate driver 6 for supplying the scan signal to the GL1 to GLn, the gamma voltage supply unit 8 for supplying the gamma voltage to the data driver 4, and the synchronization signal supplied from the system 20 are used. To generate the voltages supplied to the liquid crystal panel 2 by using the timing controller 10 for controlling the data driver 4 and the gate driver 6 and the voltage supplied from the power supply 12. DC converter (hereinafter, "DC / DC converter" And an inverter 16 for driving the box) 14, a backlight (18).

The system 20 supplies the vertical / horizontal synchronization signals Vsync and Hsync, the clock signal DCLK, the data enable signal DE and the data R, G, and B to the timing controller 10.

The liquid crystal panel 2 includes a plurality of liquid crystal cells Clc disposed in a matrix at the intersections of the data lines DL1 to DLm and the gate lines GL1 to GLn. Each TFT formed in the liquid crystal cell Clc supplies a data signal supplied from the data lines DL1 to DLm to the liquid crystal cell Clc in response to a scan signal supplied from the gate line GL. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line, or is formed between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it.

The gamma voltage supply unit 8 supplies a plurality of gamma voltages to the data driver 4.

The data driver 4 converts the digital video data R, G, and B into analog gamma voltages (data signals) corresponding to the gray scale values in response to the control signal CS from the timing controller 10. The gamma voltage is supplied to the data lines DL1 to DLm.

The gate driver 6 sequentially supplies scan pulses to the gate lines GL1 to GLn in response to the control signal CS from the timing controller 10 to supply a horizontal signal to the liquid crystal panel 2. Select.

The timing controller 10 uses a control signal for controlling the gate driver 6 and the data driver 4 by using the vertical / horizontal synchronization signals Vsync and Hsync and the clock signal DCLK input from the system 20. Generate CS). The control signal CS for controlling the gate driver 6 includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable (GOE), and the like. Included. The control signal CS for controlling the data driver 4 includes a source start pulse (SSP), a source shift clock (SSC), a source output signal (SOE), and Polarity signal (POL) is included. The timing controller 10 rearranges the data R, G, and B supplied from the system 20 and supplies the data driver 4 to the data driver 4.

The DC / DC converter 14 boosts or reduces the voltage of 3.3V input from the power supply 12 to generate the voltage supplied to the liquid crystal panel 2. The DC / DC converter 14 generates a gamma reference voltage, a gate high voltage VGH, a gate low voltage VGL, a common voltage Vcom, and the like.

The inverter 16 supplies the lamp driving power to the backlight 18 for driving the backlight 18. The backlight 18 generates light corresponding to the lamp driving power supplied from the inverter 16 and supplies the light to the liquid crystal panel 2.

In order to display the vivid image in the liquid crystal panel 2 driven as described above, the contrast between the bright image and the dark image must be clearly defined. However, in the conventional liquid crystal display, since there is no way to expand the contrast in response to the data, it is difficult to display a vivid image. In addition, the backlight 18 of the conventional liquid crystal display emits light at a constant brightness regardless of data. As such, when the backlight 18 emits light at a constant brightness regardless of data, it is difficult to display a dynamic and vivid image on the liquid crystal panel 2. For example, in order to make the blasting scene more lively, the luminance of the blasted portion should be emphasized. However, in the conventional liquid crystal display device, since the backlight 18 emits light at a constant brightness regardless of data, it is difficult to express a lively image.

Accordingly, in order to solve the above problems, the present invention provides a driving device and a driving method of a liquid crystal display device to change the brightness of the display image according to the input data and to improve the contrast.

In order to achieve the above object, a driving apparatus of a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel displaying an image corresponding to a data signal; A data driver for supplying the data signal to the liquid crystal panel; A gate driver for supplying a scan signal to the liquid crystal panel; Obtaining a histogram by dividing the luminance components of the input first data into a plurality of stages, generating second data having an expanded contrast ratio corresponding to the luminance of the histogram for each stage using an average value of the histogram, and at least according to the average value of the histogram. An image quality improving unit generating one brightness control signal; A timing controller for rearranging the second data to supply the data driver and controlling the data driver and the gate driver; A backlight for irradiating light onto the liquid crystal panel; And an inverter for driving the backlight according to the brightness control signal.

The image quality improving unit may include data modulation means for generating the second data using the first data, backlight control means for generating the at least one brightness control signal under control of the data modulation means, and an external device. And a controller configured to receive a first synchronization signal from the controller, change the input first synchronization signal to be synchronized with the second data, and supply the first synchronization signal to the timing controller.

A driving method of a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel for displaying an image corresponding to a data signal, a data driver for supplying the data signal to the liquid crystal panel, and a scan signal for supplying the scan signal to the liquid crystal panel. A method of driving a liquid crystal display device having a gate driver; Generating a histogram by dividing the luminance components of the input first data into a plurality of steps, and generating second data whose contrast ratio is extended in correspondence to the luminance of the histogram in stages using an average value of the generated histogram; And rearranging the second data to supply the data driver.

The driving method of the liquid crystal display may further include generating at least one brightness control signal according to the average value of the histogram, and irradiating light to the liquid crystal panel according to the at least one brightness control signal. It is done.

The generating of the second data may include converting the first data into a luminance component and a chrominance component, determining a number of step histograms using an average value of the histogram, and setting a slope of the step histogram; Generating a modulated luminance component by extending the contrast of the luminance component using the number and slope of the stepped histogram; and generating a delayed color difference component by delaying the color difference component until the modulated luminance component is generated. And generating the second data by mixing the modulation luminance component and the delay color difference component.

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

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

Referring to FIG. 2, in the driving apparatus of the liquid crystal display according to the first exemplary embodiment, m data lines DL1 through DLm and n gate lines GL1 through GLn intersect each other. A liquid crystal panel 22 in which thin film transistors are formed; A data driver 24 for supplying a data signal to each of the data lines DL1 to DLm; A gate driver 26 for supplying a scan signal to each of the gate lines GL1 to GLn; A histogram is obtained by dividing the luminance components of the input first data Ri, Gi, and Bi into a plurality of stages, and the second data whose contrast ratio is expanded to correspond to the luminance of the histogram for each stage using the average value of the histogram. And an image quality improving unit 42 generating Ro, Go, Bo and generating brightness control signals Dim according to the average value of the histogram; A timing controller for rearranging the second data Ro, Go, and Bo to be suitable for driving the liquid crystal panel 22 to supply the data driver 24, and to control the data driver 24 and the gate driver 26. 30; A backlight 38 for irradiating light to the liquid crystal panel 22 and an inverter 36 for driving the backlight 38 according to the brightness control signal Dim are provided.

In addition, the driving device of the liquid crystal display according to the first embodiment of the present invention includes first data (Ri, Gi, Bi). A system 40 for generating the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, the first data enable signal DE1 and the driving power Vin; The timing controller 30, the gamma voltage supply unit 28, and the data driver are generated using the gamma voltage supply unit 28 that generates and supplies the gamma voltage to the data driver 24, and the driving power source Vin from the system 40. The power supply unit 32 generates driving voltages required for driving the gate driver 26 and the gate driver 26, and the voltages supplied to the liquid crystal panel 22 are generated using the voltage supplied from the power supply unit 32. It further includes a current / DC converter (hereinafter referred to as "DC / DC converter") 34.

The system 40 improves the quality of the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, the first data enable signal DE1, and the first data Ri, Gi, Bi. The power supply unit 32 supplies the drive power Vin from the outside to the power supply unit 32.

The DC / DC converter 34 generates a voltage supplied to the liquid crystal panel 22 by increasing or decreasing the voltage of 3.3V input from the power supply unit 32. The DC / DC converter 34 generates a gamma reference voltage, a gate high voltage VGH, a gate low voltage VGL, a common voltage Vcom, and the like.

The liquid crystal panel 22 includes a plurality of liquid crystal cells Clc disposed in a matrix at the intersections of the data lines DL1 to DLm and the gate lines GL1 to GLn. Each TFT formed in the liquid crystal cell Clc supplies a data signal supplied from the data lines DL1 to DLm to the liquid crystal cell Clc in response to a scan signal supplied from the gate line GL. In addition, a storage capacitor Cst is formed in each of the liquid crystal cells Clc. The storage capacitor Cst is formed between the pixel electrode of the liquid crystal cell Clc and the front gate line, or is formed between the pixel electrode of the liquid crystal cell Clc and the common electrode line to maintain a constant voltage of the liquid crystal cell Clc. Let's do it.

The gamma voltage supply unit 28 generates a plurality of different reference gamma voltages using the driving voltage from the power supply unit 32 and supplies them to the data driver 24.

The image quality improving unit 42 may generate first data according to the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, and the first data enable signal DE1 supplied from the system 40. Histograms by dividing the luminance components of the fields Ri, Gi, and Bi into a plurality of stages, and using the average value of the histograms, the second data (Ro, Go, Bo) whose contrast ratio is expanded to correspond to the luminance of the histogram of each stage. Is generated and supplied to the timing controller 30.

In addition, the image quality improving unit 42 generates a brightness control signal Dim according to the average value of the histogram and supplies it to the inverter 36.

In addition, the image quality improving unit 42 may synchronize the second vertical / horizontal synchronization signals Vsync2 and Hsync2, the second clock signal DCLK2, and the second data enable signal to synchronize the second data Ro, Go, and Bo. (DE2) is generated and supplied to the timing controller 30.

The timing controller 30 controls the gate driver 26 and the data driver 24 by using the second vertical / horizontal synchronization signals Vsync2 and Hsync2 and the second clock signal DCLK2 input from the image quality improvement unit 42. A control signal CS for control is generated.

In addition, the timing controller 30 rearranges the second data Ro, Go, and Bo supplied from the image quality improving unit 42 so as to be suitable for driving the liquid crystal panel 22 and supplies them to the data driver 24. Here, the control signal CS for controlling the gate driver 26 includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable (GOE), and the like. This includes. The control signal CS for controlling the data driver 24 includes a source start pulse (SSP), a source shift clock (SSC), a source output signal (SOE), and Polarity signal (POL) is included.

The data driver 24 includes a plurality of gammas different from each other according to gray values of the second data Ro, Go, and Bo supplied from the timing controller 30 in response to the control signal CS from the timing controller 30. One of the voltages is selected as the data signal, and the selected data signal is supplied to the data lines DL1 through DLm.

The gate driver 26 sequentially supplies scan pulses to the gate lines GL1 to GLn in response to the control signal CS from the timing controller 30 to supply a horizontal signal to the liquid crystal panel 22. Select.

The inverter 36 adjusts the lamp driving power (or AC waveform of high voltage) according to the brightness control signal Dim supplied from the image quality improving unit 42 and supplies the same to the backlight 38.

The backlight 38 generates light having a brightness corresponding to the lamp driving power supplied from the inverter 36 and irradiates the rear surface of the liquid crystal panel 22. At this time, the backlight 38 generates light by an edge type method or a direct type method and irradiates the back surface of the liquid crystal panel 22.

In the edge type backlight, the light source is disposed on a side of the light guide plate that guides the light toward the liquid crystal panel 22 and irradiates light to the liquid crystal panel 22 through the light guide plate. On the other hand, in the direct type backlight, a plurality of light sources are provided on the rear surface of the liquid crystal panel 22 to irradiate light directly to the liquid crystal panel 22.

3 is a block diagram illustrating the image quality improving unit 42 shown in FIG. 2.

Referring to FIG. 3 and FIG. 2, the image quality improving unit 42 may include the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, and the first data enable signal supplied from the system 40. The histogram is obtained by dividing the luminance components of the first data Ri, Gi, and Bi into a plurality of stages according to (DE1), and the contrast ratio is expanded to correspond to the luminance of the histogram of each stage using the average value (M) of the histogram. Data modulation means (70) for generating second data (Ro, Go, Bo) and supplying it to the timing controller (30); Backlight control means (72) for generating a brightness control signal (Dim) in accordance with the average value (M) of the histogram; A controller for generating second vertical / horizontal synchronization signals Vsync2 and Hsync2, a second clock signal DCLK2, and a second data enable signal DE2 so as to be synchronized with the second data Ro, Go, and Bo. 68).

The data modulation means 70 is a data modulation means 70, the luminance / color separation unit 50, the delay unit 52, the luminance / color mixing unit 54, histogram analysis unit 56 and histogram modulator 58 ).

The luminance / color separation unit 50 separates the first data Ri, Gi, and Bi into luminance components Y and color difference components U and V. FIG. Here, each of the luminance component Y and the color difference components U and V is obtained by the following equations (1) to (3).

Y = 0.229 × Ri + 0.587 × Gi + 0.114 × Bi

U = 0.493 × (Bi-Y)

V = 0.887 × (Ri-Y)

The luminance / color separation unit 50 supplies the luminance component Y separated from the first data Ri, Gi, and Bi to the histogram analysis unit 56 by using Equations 1 to 3, as well as the first data. The color difference components U and V separated from (Ri, Gi, Bi) are supplied to the delay unit 52.

The histogram analyzer 56 extracts the histogram by dividing the luminance component Y of each frame unit supplied from the luminance / color separation unit 50 in at least 16 steps and generates an average value, and gradients step by step based on the generated average value. Set.

4 is a block diagram illustrating a histogram analyzer 56 according to the first exemplary embodiment of the present invention.

Referring to FIG. 4 and FIG. 3, the histogram analyzer 56 may include a histogram generator 150, an average value generator 152, a frequency generator 154, a step weight setting unit 156, and a step gradient setting unit ( 158).

The histogram generating unit 150 divides the luminance component Y from the luminance / color separation unit 50 into at least 16 steps so as to correspond to each region and arranges the histogram Hist_i in the frame unit as shown in FIG. Get 1 to 16). In other words, the histogram generator 150 accumulates the luminance component Y in each step to generate histogram Hist_i for each step to grasp brightness information of the first data Ri, Gi, and Bi. For example, in FIG. 5, when the histogram Hist_i is biased toward the right side (high level), the histogram Hist_i is regarded as a bright screen, and when the histogram Hist_i is biased toward the left side (lower level), it is determined as a dark screen.

Meanwhile, the histogram generator 150 may generate the histogram Hist_i by dividing the luminance component Y from the luminance / color separator 50 into eight steps and 32 steps. For example, when the histogram Hist_i is generated by dividing the luminance component Y corresponding to the 8-bit first data Ri, Gi, and Bi in 16 levels, the histogram generator 150 may include 256 / H. 16, that is, the histogram Hist_i of the first to sixteenth steps is generated by accumulating the luminance component Y in 16 gradation units.

The average value generator 152 generates the average value M by adding up the histogram Hist_i for each step from the histogram generator 150 and dividing by 16.

The frequency generator 154 accumulates the cumulative histogram LH of the first area smaller than the mean value M and the second area larger than the mean value M according to the histogram Hist_i for each step based on the mean value M. FIG. Generate the histogram number HH and the histogram number Hisc_i for each step.

The step weight setting unit 156 may include an average value M, a cumulative histogram LH of the first region, a cumulative histogram HH of the second region, a histogram number Histc_i for each step, an adjacent histogram step Hsize, and By using the backlight weight BWL, step weights Scoe1_j and Scoe2_k of the first and second areas and brightness step Hcoe_k of the second area are set as shown in Equations 4 and 5 below. In this case, the backlight weight BWL is set to a constant of 1 to 2 from the outside in order to compensate the ratio between the minimum luminance and the maximum luminance according to the first data Ri, Gi, and Bi from the outside.

Scoe1_j = (M-1) × (Histc_i / LH)

Scoe2_k = (Hsize-M) × (Histc_i / HH)

Hcoe_k = (Hsize-BLW × M) / (Hsize-M)

In Equation 5, j represents the M stage corresponding to the average value from the first stage, k represents the i stage from the M stage.

The step slope setting unit 158 uses the minimum slope value Smin, the backlight weight BWL, the step brightness weight Hcoe_k of the second area, the first and second step weights Scoe1_j and Scoe2_k set from the outside. Set the slope (Slope_i) of the histogram for each step. At this time, the minimum slope value Smin is set to a constant between 0 and 1 in order to limit the distortion of the original image due to the extreme emphasis of contrast in smoothing the histogram.

In detail, the step slope setting unit 158 is smaller than the average value M using the minimum slope value Smin, the backlight weight BLW, and the step weight Scoe1_j of the first region as shown in Equation 6 below. The slopes Slope_1 to Slope_M of the step-by-step histogram of the first region are set.

Slope_j = BLW × (Scoe1_j × (1-Smin) + Smin)

In addition, the step slope setting unit 158 sets the slope slope_M of the step of the histogram having the average value M according to the backlight weight BWL as shown in Equation 7 below.

Slope_M = BLW

In addition, the step gradient setting unit 158 uses the minimum slope value Smin, the step weight Scoe2_k of the second area, and the step brightness weight Hcoe_k of the second area, as shown in Equation 8 below. The slopes Slope_M + 1 to Slope_i of the step-by-step histogram of the second area larger than) are set.

Slope_k = Hcoe_k × (Scoe2_j × (1-Smin) + Smin)

The step gradient setting unit 158 sets the slopes Slope_1 to Slope_16 of the histograms of the first to i th stages, that is, the first to the sixteenth stages, and supplies them to the histogram modulator 58.

On the other hand, the histogram analyzer 56 supplies the average value M generated by the average value generator 152 to the backlight control means 72.

As such, the histogram analyzer 56 extracts the histogram Hist_i for each 16 stages from the luminance component Y of one frame to generate an average value M, and the slope of each stage histogram slope Slope_1 based on the average value M. FIG. To Slope_16 are set and supplied to the histogram modulator 58.

The histogram modulator 58 uses the slope of the histogram stepwise from the histogram analyzer 56 (Slope_1 to Slope_16), the current histogram step (X_i), the previous histogram step (Xoffset), and the histogram number (Yoffset) of the previous step. According to Equation 9 below, as shown in FIG. 5, modulation of the contrast of the luminance component Y supplied from the luminance / color separation unit 50 is expanded to generate modulation luminance components YM_i for each stage as illustrated in FIG. 6. .

YM_i = Slope_i × (X_i-Xoffset) + Yoffset

Meanwhile, the histogram modulator 58 temporarily stores the histogram number Histc_i for each step supplied from the frequency generator 154 of the histogram analyzer 56 to store the current histogram step X_i and the previous histogram step Xoffset. And a register providing the histogram number Yoffset of the previous step.

Accordingly, the histogram modulator 58 subtracts the previous histogram step Xoffset from the current histogram step X_i provided from the register and multiplies the slope Slope_i corresponding to the current histogram step X_i to perform the previous step. By adding the histogram number (Yoffset), the modulation luminance component YM_i for each step is generated.

Specifically, the histogram modulator 58 may know the Y-intercept of the current histogram step by the histogram number Yoffset of the previous step, and the slope of the current histogram step X_i to the slope Slope_i and the current histogram step X_i. By setting the slope of the current histogram step, the modulation luminance component YM_i of the current histogram can be known. Therefore, the gray level of the modulation luminance component YM is distributed over the entire region as shown in FIG. 7, so that contrast between dark and bright luminance may be clearly displayed.

Meanwhile, the delay unit 52 delays the color difference components U and V while the luminance component Y is analyzed by the histogram analyzer 56 and the histogram modulator 58 to delay the color difference components UD and VD. Create The delay unit 52 supplies the delay color difference components UD and VD to the luminance / color mixing unit 54 in synchronization with the modulation luminance component YM.

The luminance / color mixing unit 54 generates the second data Ro, Go, and Bo by using the modulation luminance component YM and the delay color difference components UD and VD. In this case, the second data Ro, Go, and Bo are obtained by the following equations 10 to 12.

Ro = YM + 0.000 × UD + 1.140 × VD

Go = YM-0.396 × UD-0.581 × VD

Bo = YM + 2.029 × UM + 0.000 × VM

The operation of the data modulation means 70 will be described in detail as follows.

First, the luminance / color separation unit 50 separates the first data Ri, Gi, and Bi into luminance components Y and color difference components U and V by using Equations 1 to 3 below. Here, the luminance component Y is input to the histogram analyzer 56 and the color difference components U and V are input to the delay unit 52.

Subsequently, the histogram analyzing unit 56 classifies the histogram Hist_i by dividing the luminance component Y in a frame unit supplied from the luminance / color separation unit 50 in at least 16 steps by using Equations 4 to 8. The average value M is extracted to generate the average value M, and the first to sixteenth step slopes Slope_1 to Slope_16 are set based on the generated average value M. FIG. The histogram analyzer 56 supplies the set first to sixteenth grades slope_1 to slope_16 to the histogram modulator 58, and supplies the generated average value M to the backlight control means 72. .

Then, the histogram modulator 58 expands the luminance component Y so that the luminance component Y is distributed over the entire gray scale region according to the first to sixteenth step slopes Slope_1 to Slope_16 set using Equation 9 below. The modulation luminance component YM is generated and supplied to the luminance / color mixing unit 54.

The luminance / color mixing unit 54 generates the second data Ro, Go, and Bo according to the delay color difference components UD and VD and the modulation luminance component YM using Equations 10 to 12. In this case, since the second data Ro, Go, and Bo are generated by the modulation luminance component YM, the second data Ro, Go, and Bo have a distinct contrast.

Accordingly, in the present invention, the modulation luminance component YM may be distributed over the entire gradation region to generate second data Ro, Go, Bo having a distinct contrast, and thus a vivid image may be generated in the liquid crystal panel 22. I can display it. In other words, lighter colors appear brighter and darker parts become darker, which emphasizes contrast.

Meanwhile, the backlight control unit 72 of the present invention generates a brightness control signal Di corresponding to the average value M supplied from the histogram analyzer 56, and converts the generated brightness control signal Dim into an inverter ( 36).

To this end, the backlight control means 72 of the present invention includes a backlight controller 60 and a digital / analog converter 62.

The backlight controller 60 generates a brightness control signal Dim corresponding to the average value M supplied from the histogram analyzer 56. In this case, the backlight controller 60 generates a brightness control signal Dim so that light having a high luminance can be generated when the backlight controller 60 has a high luminance of the average value M, and has a low luminance when the average value M has a low luminance. Generates a brightness control signal (Dim) so that the light can be generated.

The digital / analog converter 62 converts the brightness control signal Dim into analog and supplies it to the inverter 36.

Accordingly, the inverter 36 supplies the lamp driving power corresponding to the brightness control signal Dim to the backlight 38. Therefore, the backlight 38 generates light of brightness corresponding to the lamp driving power supplied from the inverter 36 and irradiates the liquid crystal panel 22. That is, the backlight controller 60 of the present invention displays the bright color displayed on the liquid crystal panel 22 more brightly and displays the dark color darker according to the average value M from the histogram analyzer 56. By controlling the light 38, the contrast can be made clear while maintaining the average brightness of the image displayed on the liquid crystal panel 22.

Meanwhile, the controller 68 of the present invention receives the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, and the first data enable signal DE1 input from the system 40. . The controller 68 may synchronize the second vertical / horizontal synchronization signals Vsync2 and Hsync2, the second clock signal DCLK2, and the second data enable signal DE2 to synchronize the second data Ro, Go, and Bo. Is generated and supplied to the timing controller 30.

The driving apparatus and driving method of the liquid crystal display according to the embodiment of the present invention as described above, each step slope based on the average value (M) of the histogram extracted from the luminance component (Y) of the first data (Ri, Gi, Bi) By setting the second data (Ro, Go, Bo) to set the contrast of the overall brightness can be displayed a dynamic and lively image. In other words, according to the present invention, bright brightness is brighter, dark brightness is darker, and the brightness of the backlight 38 is adjusted according to the brightness of the screen of one frame, thereby displaying a lively and dynamic image.

In the case of applying the present invention, the sky region is displayed brighter and the mountain region is displayed darker as shown in FIG. 8, so that the contrast can be displayed more clearly while maintaining the average brightness of the image. At this time, the brightness of the light irradiated from the backlight to the liquid crystal panel in FIG. 8 is reduced by the average value due to the brightness of the brightness portion such as the sky and the brightness of the dark portion such as the mountain. Accordingly, the present invention can reduce the power consumption by adjusting the tube current of the backlight 38 according to the average value.

9 is a block diagram illustrating a histogram analyzer 56 according to a second exemplary embodiment of the present invention illustrated in FIG. 3.

9, the histogram analyzer 56 according to the second exemplary embodiment of the present invention may include a histogram generator 150, an average value generator 152, a frequency generator 154, and a step weight setting unit. 156, a minimum inclination setting unit 157, and a step inclination setting unit 158.

The histogram analysis unit 56 according to the second embodiment of the present invention is the first embodiment of the present invention shown in FIG. 4 except for the minimum slope setting unit 157 and the stepped slope setting unit 158. It has the same configuration as the histogram analyzer 56 according to. Accordingly, descriptions of other components except the minimum slope setting unit 157 and the step gradient setting unit 158 will be replaced with the description of the histogram analyzer 56 according to the first embodiment of the present invention. do.

In the histogram analyzer 56 according to the second embodiment of the present invention, the minimum slope setting unit 157 may include the minimum slope value Smin, the total number of steps Histt and the histogram Hist_i of the histogram Hist_i input from the outside. The minimum slope value (Slmin) and the median of the lower region where the mean value (M) is smaller than the mean value (Histm) using the median value (Histm) of the total number of steps (Histt) and the mean value (M) of the histogram (Hist_i). The minimum slope value Shmin of the upper region larger than the value Hictm is set and supplied to the stepped slope setting unit 158. At this time, the minimum slope value Smin input from the outside is set to a constant between 0 and 1 in order to limit the distortion of the original image due to the extreme emphasis of contrast in smoothing the histogram.

Specifically, the minimum slope setting unit 157 may determine the total number of steps Histt as shown in Equation 13 below when the median value Histm of the total number of steps Histt of the histogram Hist_i is less than or equal to the average value M. FIG. ), The minimum slope value (Slmin) of the lower region is set according to the median value (Histm), the average value (M), and the minimum slope value (Smin). That is, the minimum slope setting unit 157 sets the minimum slope value Slmin of the lower region when the average value M of the histogram Hist_i is a value between the first to n / 2 histogram steps Hist_1 to Hist_i / 2. Set it.

Slmin = (1-(Histt-Histm) / (Histm-1)) × (1-Smin)

In addition, the minimum slope setting unit 157 may determine the total number of steps (Histt) and the median as shown in Equation 14 below when the median value (Histm) of the total number of steps (Histt) of the histogram (Hist_i) is larger than the average value (M). The minimum slope value Shmin of the upper region is set according to the value Hism and the minimum slope value Smin. That is, the minimum slope setting unit 157 may determine the minimum slope value of the upper region when the average value M of the histogram Hist_i is a value between n / 2 + 1 to nth histogram steps Hist_i / 2 + 1 to Hist_i. Set (Shmin).

The minimum slope setting unit 157 may determine the minimum slope values Slmin and Shmin of the lower and upper regions according to the average value M of the histograms based on the median value Hist of the total number of stages Hist_i of the histogram Hist_i. ) To maintain the brightness of the image.

Shmin = 1-(1-Smin) × (Histm-1) / (Histt-Histm)

The step slope setting unit 158 may include the minimum slope values Slmin and Shmin of the lower and upper regions input from the minimum slope setting unit 157, the backlight weight BLW, the step brightness brightness Hk_k of the second region, The slope Slope_i of each histogram is set using the first and second weights Scoe1_j and Scoe2_k.

In detail, the step slope setting unit 158 uses the minimum slope value Slmin, the backlight weight BLW, and the step weight Scoe1_j of the first area as shown in Equation 15 below to obtain an average value M. FIG. The slopes Slope_1 to Slope_M for each step of the first area smaller than) are set.

Slope_j = BLW × (Scoe1_j × (1-Slmin) + Slmin)

In addition, the step setting unit 158 sets the slope (Slope_M) of the average value M according to the backlight weight BWL as shown in Equation 16 below.

Slope_M = BLW

The gradient setting unit 158 of the second area larger than the average value M is obtained by using the minimum slope value Shmin of the upper area and the brightness weight Hcoe_k of the second area as shown in Equation 17 below. Each step slope (Slope_M + 1 to Slope_i) is set.

Slope_k = Hcoe_k × (Scoe2_j × (1-Shmin) + Shmin)

The step gradient setting unit 158 sets the slopes Slope_1 to Slope_16 of the histograms of the first to i th stages, that is, the first to the sixteenth stages, and supplies them to the histogram modulator 58.

On the other hand, the histogram modulator 58 measures the slope of the histogram step by step histogram analyzer 56 (Slope_1 to Slope_16), the current histogram step (X_i), the previous histogram step (Xoffset) and the number of histograms (Yoffset) of the previous step. By using the above-described equation (9) to modulate so that the contrast of the luminance component (Y) supplied from the luminance / color separation unit 50 as shown in FIG. 10 is expanded to modulate each of the modulation luminance component (YM_i) as shown in FIG. Create In this case, the gray level of the modulation luminance component YM is distributed over the entire region as shown in FIG. 12, so that contrast may be clearly displayed while maintaining the average brightness of the original image.

As described above, the driving device and the driving method of the liquid crystal display according to the first embodiment of the present invention including the histogram analyzer 56 according to the second embodiment of the present invention include first data (Ri, Gi, Bi). Extract the histogram of the multiple stages from the luminance component (Y) of to obtain the average value (M) of the histogram, and based on the mean value (M) of the histograms of the multiple stages, the minimum slope of the lower and upper regions By limiting the values (Slmin and Shmin), you can set the slope of the histogram step by step to sharpen the contrast of the overall brightness to display a dynamic and vibrant image. In other words, according to the present invention, bright brightness is brighter, dark brightness is darker, and the brightness of the backlight 38 is adjusted according to the brightness of the screen of one frame, thereby displaying a lively and dynamic image.

In the case of applying the present invention, the sky region is displayed brighter and the mountain region is displayed darker as shown in FIG. 13, so that the contrast can be displayed more clearly while maintaining the average brightness of the image. In this case, in FIG. 13, the brightness of light irradiated from the backlight to the liquid crystal panel is reduced by an average value due to the brightness of the brightness portion such as the sky and the brightness of the dark portion such as the mountain. Accordingly, the present invention can reduce the power consumption by adjusting the tube current of the backlight 38 according to the average value.

FIG. 14 is a block diagram illustrating a driving apparatus of a liquid crystal display according to a second exemplary embodiment of the present invention, and FIG. 15 is a block diagram illustrating an image quality improvement unit illustrated in FIG. 14.

14 and 15, in the driving apparatus of the liquid crystal display according to the second exemplary embodiment, m data lines DL1 through DLm and n gate lines GL1 through GLn cross each other. A liquid crystal panel 22 in which thin film transistors are formed at intersections; A data driver 24 for supplying a data signal to each of the data lines DL1 to DLm; A gate driver 26 for supplying a scan signal to each of the gate lines GL1 to GLn;

The histogram is obtained by dividing the luminance components of the input first data Ri, Gi, and Bi into a plurality of stages, and the second data Ro whose contrast ratio is extended in correspondence to the luminance of the histogram for each stage using an average value of the histogram. And an image quality improving unit 80 generating Go, Bo, and generating a plurality of brightness control signals Dim1 to Dimx according to the first data Ri, Gi, and Bi; A timing controller for rearranging the second data Ro, Go, and Bo to be suitable for driving the liquid crystal panel 22 to supply the data driver 24, and to control the data driver 24 and the gate driver 26. 30; A backlight 84 for irradiating light to the liquid crystal panel 22 using the plurality of lamps 91 to 9x and an inverter for driving the backlight 84 according to the plurality of brightness control signals Dim1 to Dimx ( 82).

In addition, the driving apparatus of the liquid crystal display according to the second embodiment of the present invention may include first data (Ri, Gi, Bi). A system 40 for generating the first vertical / horizontal synchronization signals Vsync1 and Hsync1, the first clock signal DCLK1, the first data enable signal DE1 and the driving power Vin; The timing controller 30, the gamma voltage supply unit 28, and the data driver are generated using the gamma voltage supply unit 28 that generates and supplies the gamma voltage to the data driver 24, and the driving power source Vin from the system 40. 24 and the voltages supplied to the liquid crystal panel 22 using the voltage supplied from the power supply 32 to generate a driving voltage necessary for driving the gate driver 26. A DC / DC converter (hereinafter, referred to as a "DC / DC converter") 34 is further provided.

The driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention is the first embodiment of the present invention shown in FIG. 2 except for the image quality improving unit 80, the inverter 82, and the backlight 84. It has the same structure as the drive device of the liquid crystal display device according to the example. Accordingly, descriptions of other configurations except the image quality improving unit 80, the inverter 82, and the backlight 84 will be described with reference to the driving apparatus of the liquid crystal display according to the first embodiment of the present invention. Let's do it.

In the driving apparatus of the liquid crystal display according to the second exemplary embodiment of the present invention, the image quality improving unit 80 may include the first vertical / horizontal synchronization signals Vsync1 and Hsync1 supplied from the system 40 as shown in FIG. 15. A histogram is obtained by dividing the luminance components of the first data Ri, Gi, and Bi according to the first clock signal DCLK1 and the first data enable signal DE1 into a plurality of stages, and calculating an average value of the histogram. Data modulation means (70) for generating second data (Ro, Go, Bo) whose contrast ratio is expanded to correspond to the luminance of the histogram in stages, and supplying the second data (Ro, Go, Bo) to the timing controller (30); Backlight control means (92) for generating a plurality of brightness control signals (Dim1 to Dimx) according to the luminance component of the first data (Ri, Gi, Bi); A controller for generating second vertical / horizontal synchronization signals Vsync2 and Hsync2, a second clock signal DCLK2, and a second data enable signal DE2 so as to be synchronized with the second data Ro, Go, and Bo. 68).

The image quality improving unit 80 has the same configuration as that of the image quality improving unit 42 shown in FIG. 3 except for the backlight control unit 92. Accordingly, the description of the other components except for the backlight control means 92 will be replaced with the description of the driving apparatus of the liquid crystal display according to the first embodiment of the present invention.

The backlight control unit 92 generates a plurality of brightness control signals Dim1 to Dimx corresponding to the average value M from the histogram analyzers according to the first and second embodiments of the present invention. A plurality of brightness control signals Dim1 to Dimx are supplied to the inverter 82.

To this end, the backlight control means 92 of the present invention includes a backlight controller 94 and a digital / analog converter 96.

The backlight controller 94 generates a plurality of brightness control signals Dim1 to Dimx corresponding to the average value M. FIG. In this case, the backlight controller 94 generates a plurality of brightness control signals Dim1 to Dimx so that light having a high luminance may be generated when the backlight controller 94 has a high luminance of the average value M, and the average value M has a low luminance. If so, a plurality of brightness control signals Dim1 to Dimx are generated to generate light of low luminance.

The digital / analog converter 96 converts the plurality of brightness control signals Dim1 to Dimx into analog and supplies them to the inverter 82.

On the other hand, the inverter 82 supplies a plurality of lamp driving powers corresponding to the plurality of brightness control signals Dim1 to Dimx to the backlight 84.

The backlight 84 is selected in a direct fashion including a plurality of lamps 91-9x. Here, each of the plurality of lamps 91 to 9x is installed on the rear surface of the liquid crystal panel 22 to generate light corresponding to the plurality of lamp driving powers supplied from the inverter 82 and irradiate the liquid crystal panel 22. .

Meanwhile, the plurality of lamps 91 to 9x may be disposed in x zones so as to face the rear surface of the liquid crystal panel 22. Accordingly, the liquid crystal panel 22 may be divided into x zones in which light is radiated from each of the plurality of lamps 91 to 9x.

In practice, the backlight controller 94 generates a plurality of brightness control signals Dim1 to Dimx in response to data supplied to the x zones of the liquid crystal panel 22.

Accordingly, the backlight 84 drives each of the plurality of lamps 91 to 9x so as to correspond to the plurality of lamp driving powers supplied from the inverter 82 according to the average value M, so as to have x zones of the liquid crystal panel 22. Light is irradiated to each.

The driving apparatus and driving method of the liquid crystal display according to the second exemplary embodiment of the present invention are based on the average value M of the histogram extracted from the luminance component Y of the first data Ri, Gi, and Bi. Each of the plurality of lamps 91 to 9x is individually generated by generating the second data Ro, Go, Bo by setting the inclination of each step, and generating a plurality of brightness control signals Dim1 to Dimx according to the average value M. It is possible to display a dynamic and lively image by sharpening the contrast of the overall brightness by driving. In other words, in the present invention, bright brightness is brighter, dark brightness is darker, and the brightness of the backlight 84 is adjusted according to the brightness of the screen of one frame, thereby displaying a lively and dynamic image.

In addition, the driving device and the driving method of the liquid crystal display according to the second embodiment of the present invention generate a plurality of brightness control signals (Dim1 to Dimx) to display an image displayed by individually driving the plurality of lamps (91 to 9x) The luminance of can be selectively emphasized.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention It will be apparent to those skilled in the art.

The histogram is obtained by dividing the luminance component into a plurality of steps from the input data according to the embodiment of the present invention as described above, and the contrast is maintained while maintaining the average brightness of the displayed image by setting the step gradient of the histogram using the average value of the histogram. You can improve the contrast. Furthermore, the present invention can display a more lively and dynamic image by controlling the brightness of the backlight according to the average value of the histogram.

In addition, the present invention is to prevent the distortion of the brightness of the image due to the expansion of the contrast by setting the minimum slope value of the upper region and the lower region individually based on the median value of the total number of steps of the histogram according to the average value of the histogram. Can be.

Claims (29)

  1. A liquid crystal panel displaying an image corresponding to the data signal;
    A data driver for supplying the data signal to the liquid crystal panel;
    A gate driver for supplying a scan signal to the liquid crystal panel;
    Obtaining a histogram by dividing the luminance components of the input first data into a plurality of stages, generating second data having an expanded contrast ratio corresponding to the luminance of the histogram for each stage using an average value of the histogram, and at least according to the average value of the histogram. An image quality improving unit generating one brightness control signal;
    A timing controller for rearranging the second data to supply the data driver and controlling the data driver and the gate driver;
    A backlight for irradiating light onto the liquid crystal panel;
    An inverter for driving the backlight according to the brightness control signal,
    The image quality improvement unit
    Data modulation means for generating the second data using the first data;
    Backlight control means for generating the at least one brightness control signal under control of the data modulation means;
    A control unit configured to receive a first synchronization signal from an external source, change the received first synchronization signal to be synchronized with the second data, and supply the first synchronization signal to the timing controller;
    The data modulation means
    A luminance / color separation unit for converting the first data into a luminance component and a color difference component;
    A histogram analyzer for dividing the luminance components of the first data into a plurality of steps to obtain the histogram, and using the average value of the histogram to determine the number and slope of the histograms in each step;
    A histogram modulator for generating a modulated luminance component by extending the contrast of the luminance component using the number and slope of the stepped histograms;
    A delay unit generating a delayed color difference component by delaying the color difference component until the modulated luminance component is generated by the histogram analyzer;
    And a luminance / color mixing unit configured to generate the second data by mixing the modulation luminance component and the delay color difference component.
  2. delete
  3. delete
  4. The method of claim 1,
    The histogram analysis unit;
    A histogram generator for generating the histogram for each step by dividing the luminance component of the first data into a plurality of steps;
    An average value generator for accumulating the histogram and generating an average value;
    A frequency generator for generating a cumulative histogram number of the first region smaller than the average value, a cumulative histogram number of the second region larger than the average value, and a stepped histogram number using the histogram and the average value;
    Step weights for setting step weights of the first and second areas and step weight brightness of the second area by using the backlight weight from the outside, the cumulative histogram number of the first and second areas, the average value, and the step histogram number. A setting unit;
    And a step slope setting unit configured to set a slope of the step histogram using a minimum slope value from the outside, the backlight weight, the step weights of the first and second areas, and the step brightness brightness of the second area. Drive of display device.
  5. The method of claim 1,
    The histogram analysis unit;
    A histogram generator for generating the histogram for each step by dividing the luminance component of the first data into a plurality of steps;
    An average value generator for accumulating the histogram and generating an average value;
    A frequency generator for generating a cumulative histogram number of the first region smaller than the average value, a cumulative histogram number of the second region larger than the average value, and a stepped histogram number using the histogram and the average value;
    Step weights for setting step weights of the first and second areas and step weight brightness of the second area by using the backlight weight from the outside, the cumulative histogram number of the first and second areas, the average value, and the step histogram number. A setting unit;
    The minimum slope value of the upper region where the average value is greater than the median value and the lower region smaller than the median value using a minimum slope value from the outside, the average value, the total number of steps of the histogram, and the median value of the total steps of the histogram. A minimum slope setting unit for setting a minimum slope value of the unit;
    And a stepped slope setting unit configured to set a slope of the stepped histogram by using the minimum slope value of the upper and lower regions, the backlight weight, the staged weights of the first and second regions, and the staged brightness weights of the second region. A drive device for a liquid crystal display device.
  6. The method according to claim 4 or 5,
    The backlight weight is a driving device of the liquid crystal display, characterized in that the constant is set to 1-2.
  7. The method according to claim 4 or 5,
    The minimum slope value is a driving device of the liquid crystal display, characterized in that the constant is set to 0 ~ 1.
  8. The method according to claim 4 or 5,
    The step weight setting unit,
    Step weights of the first region are set by ((average value-1) × (number of histograms per step / cumulative histograms of the first region)),
    Step weights of the second area are set by ((adjacent histogram step-average value) x (number of histograms per step / cumulative histograms of the second area)),
    And setting (by adjacent histogram step-backlight weight x average value) / (adjacent histogram step-average value) the step-by-step brightness weight of the second area.
  9. The method of claim 4, wherein
    The step setting unit step,
    Set the stepped slope of the first area by (backlight weight × (weighted step by step 1 × (1-minimum slope value) + minimum slope value),
    Setting a slope of the histogram step having the average value by the backlight weight,
    And setting the slope of the step-by-step histogram of the second area by (step brightness weight of the second area x (step weight of the second area x (1-minimum slope value) + minimum slope value)). Drive.
  10. 6. The method of claim 5,
    The minimum slope setting unit,
    The minimum slope value of the subregion by (1-(total number of steps in the histogram-median) / (middle-1)) x (1-minimum slope value) when the average value is less than or equal to the median value , Set
    Setting the upper minimum slope value by (1-(1-minimum slope value) x (median value-1) / (total number of steps in the histogram-median value)) when the average value is larger than the median value. A drive device for a liquid crystal display device.
  11. 11. The method of claim 10,
    The step setting unit step,
    Set the stepped slope of the first area by (backlight weight × (stepwise weight of the first area × (1-the minimum slope value of the subarea) + the minimum slope value of the subarea),
    Setting a slope of the histogram step having the average value by the backlight weight,
    Setting the slope of the step-by-step histogram of the second area by the step-by-step brightness weight of the second area × (the step-by-step weight of the second area × (1-the minimum slope value of the upper region) + the minimum slope value of the upper region) A drive device for a liquid crystal display device.
  12. The method according to claim 4 or 5,
    And the histogram modulator generates the modulation luminance component by (slope of step histogram x (step of current histogram-step of previous histogram) + number of histograms of previous step).
  13. The method of claim 1,
    The backlight control means,
    A backlight controller for generating the at least one brightness control signal according to the average value of the histogram;
    And a digital / analog converter for converting the at least one brightness control signal generated by the backlight controller into an analog signal.
  14. The method of claim 1,
    The backlight device includes at least one lamp for dividing the liquid crystal panel into a plurality of zones to irradiate light.
  15. 15. The method of claim 14,
    The backlight control means generates and supplies the at least one brightness control signal to the inverter to generate light that is proportional to the divided luminances of the plurality of zones in the lamp. Device.
  16. A liquid crystal display device comprising: a liquid crystal panel for displaying an image corresponding to a data signal, a data driver for supplying the data signal to the liquid crystal panel, and a gate driver for supplying a scan signal to the liquid crystal panel;
    Generating a histogram by dividing the luminance components of the input first data into a plurality of steps, and generating second data whose contrast ratio is extended in correspondence to the luminance of the histogram in stages using an average value of the generated histogram;
    Reordering the second data to supply the data driver;
    Generating the second data may include
    Converting the first data into a luminance component and a chrominance component;
    Determining the number of step histograms using the average value of the histogram and setting the slope of the step histogram;
    Generating a modulated luminance component by extending the contrast of the luminance component using the number and slope of the step histogram;
    Delaying the color difference component until the modulated luminance component is generated to generate a delayed color difference component;
    And mixing the modulated luminance component and the delayed chrominance component to generate the second data.
  17. 17. The method of claim 16,
    Generating at least one brightness control signal according to the average value of the histogram;
    And irradiating light to the liquid crystal panel according to the at least one brightness control signal.
  18. delete
  19. 17. The method of claim 16,
    Setting the number and the slope of the step-by-step histogram;
    Generating the step histogram by dividing the luminance component into a plurality of steps;
    Accumulating the histogram to generate an average value;
    Generating a cumulative histogram number of the first region smaller than the average value, a cumulative histogram number of the second region larger than the average value, and a stepped histogram number using the histogram and the average value;
    Setting step weights of the first and second areas and step weight brightness of the second area by using the backlight weight from the outside, the cumulative histogram number of the first and second areas, the average value, and the number of step histograms; ;
    And setting a slope of the stepped histogram using a minimum slope value from the outside, the backlight weight, the stepped weights of the first and second regions, and the stepped brightness weights of the second region. Driving method.
  20. 17. The method of claim 16,
    Setting the number and the slope of the step-by-step histogram;
    Generating the step histogram by dividing the luminance component into a plurality of steps;
    Accumulating the histogram to generate an average value;
    Generating a cumulative histogram number of the first region smaller than the average value, a cumulative histogram number of the second region larger than the average value, and a stepped histogram number using the histogram and the average value;
    Setting step weights of the first and second areas and step weight brightness of the second area by using the backlight weight from the outside, the cumulative histogram number of the first and second areas, the average value, and the number of step histograms; ;
    The minimum slope value of the upper region where the average value is greater than the median value and the lower region smaller than the median value using a minimum slope value from the outside, the average value, the total number of steps of the histogram, and the median value of the total steps of the histogram. Setting a minimum slope value of;
    And setting a slope of the step histogram by using the minimum slope value of the upper and lower regions, the backlight weight, the stage weights of the first and second regions, and the stage brightness weights of the second region. Method of driving a liquid crystal display device.
  21. The method of claim 19 or 20,
    And the backlight weight is set to a constant 1 to 2.
  22. The method of claim 19 or 20,
    The minimum slope value is set to a constant 0 to 1, the driving method of the liquid crystal display.
  23. The method of claim 19 or 20,
    Setting the step weights of the first and second areas and the step weight weighting values of the second area may include:
    Step weights of the first region are set by ((average value-1) × (number of histograms per step / cumulative histograms of the first region)),
    Step weights of the second area are set by ((adjacent histogram step-average value) x (number of histograms per step / cumulative histograms of the second area)),
    And setting (by adjacent histogram step-backlight weight × average value) / (adjacent histogram step-average value) the step-by-step brightness weight of the second area.
  24. 20. The method of claim 19,
    Setting the slope of the step-by-step histogram,
    Set the stepped slope of the first area by (backlight weight × (weighted step by step 1 × (1-minimum slope value) + minimum slope value),
    Setting a slope of the histogram step having the average value by the backlight weight,
    (C) setting the inclination of the step histogram of the second area by (step brightness of the second area x (step weight of the second area x (1-minimum slope value) + minimum slope value)). Driving method.
  25. 21. The method of claim 20,
    Setting the upper and lower minimum slope values,
    The minimum slope value of the subregion by (1-(total number of steps in the histogram-median) / (middle-1)) x (1-minimum slope value) when the average value is less than or equal to the median value , Set
    Setting the upper minimum slope value by (1-(1-minimum slope value) x (median value-1) / (total number of steps in the histogram-median value)) when the average value is larger than the median value. A method of driving a liquid crystal display device.
  26. 26. The method of claim 25,
    Setting the slope of the step-by-step histogram,
    Set the stepped slope of the first area by (backlight weight × (stepwise weight of the first area × (1-the minimum slope value of the subarea) + the minimum slope value of the subarea),
    Setting a slope of the histogram step having the average value by the backlight weight,
    Setting the slope of the step-by-step histogram of the second area by the step-by-step brightness weight × of the second area × (weighted step-by-step x (1-minimum slope value of the upper area) + minimum slope value of the upper area)). A method of driving a liquid crystal display device.
  27. The method of claim 19 or 20,
    The generating of the modulated luminance component may include generating the modulated luminance component by (slope of step histogram × (step of current histogram minus step of previous histogram) + number of histograms of previous stage). Driving method.
  28. The method of claim 17,
    Irradiating light to the liquid crystal panel,
    Generating a lamp driving power by converting the at least one brightness control signal into an analog signal;
    And driving at least one lamp for irradiating light by dividing the liquid crystal panel into a plurality of zones by using the lamp driving power.
  29. 29. The method of claim 28,
    Generating the at least one brightness control signal
    And generating the at least one brightness control signal to generate light from the lamp, the light being proportional to the divided plurality of zone-specific luminances.
KR1020050058622A 2005-06-30 2005-06-30 Apparatus and Method for Driving Liquid Crystal Display Device KR101174782B1 (en)

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US11/415,747 US7609244B2 (en) 2005-06-30 2006-05-02 Apparatus and method of driving liquid crystal display device
JP2006176223A JP4541325B2 (en) 2005-06-30 2006-06-27 Driving device and driving method for liquid crystal display device
CNB2006100907368A CN100449603C (en) 2005-06-30 2006-06-28 Apparatus and method of driving liquid crystal display device

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