KR20130001648A - Backlight control circuit and method, lcd applyed thereof - Google Patents

Abstract

PURPOSE: A dimming control circuit and method, and a liquid crystal display device applying the same are provided to reduce power consumption by differently controlling a brightness value of each block according to an image. CONSTITUTION: A timing controller(30) generates various control signals by receiving a data signal, and various control signals from an external system(25). The timing controller supplies a gate control signal and a data control signal to a gate driver(50) and a data driver(60). The timing controller supplies an image signal to a dimming control circuit(70). A peak brightness determining part receives the modulated image signal. The peak brightness determining part generates a peak brightness signal. A block position calculator analyzes the modulated image signal. The block position calculator generates a position signal for each block. [Reference numerals] (25) External system; (30) Timing controller; (50) Gate driver; (60) Data driver; (70) Dimming control circuit; (80) Backlight driver; (90) Backlight

Description

Dimming control circuit and method, liquid crystal display device using the same {BACKLIGHT CONTROL CIRCUIT AND METHOD, LCD APPLYED THEREOF}

The present invention relates to a local dimming control circuit and a liquid crystal display device, and a liquid crystal display device to which a local dimming method for dividing a screen into a plurality of logical blocks is applied, and a dimming control circuit and method provided therewith, The present invention relates to an applied liquid crystal display device.

The liquid crystal display device is a light emitting device, unlike other flat panel display devices using other self-luminous devices, and displays an image by using external light or having a backlight as a separate light source.

The quality of an image implemented by such a liquid crystal display device depends largely on the contrast ratio, and one of the techniques proposed to improve the backlight dimming is a backlight corresponding to the image displayed on the liquid crystal panel. It is a technique to improve the contrast ratio by adaptively controlling the luminance.

The above-described backlight dimming method is divided into a global dimming method for adjusting the brightness of the entire screen and a local dimming method for locally adjusting the brightness of the screen. The global dimming method is a backlight control method that improves the dynamic contrast measured between the previous frame and the next frame by adjusting the luminance of the entire display surface, and the local dimming method locally adjusts the luminance of the display surface within one frame period. This is a backlight control method that improves static contrast, which is difficult to improve by global dimming method by controlling with.

In particular, in order to maximize the efficiency of the above-described local dimming method, by controlling the backlight of some logical blocks so that the entire backlight is turned on, that is, emits light with a higher luminance than the full-white state, A peak luminance driving technique has been proposed that achieves an effect of improving contrast ratio and improving image quality.

1A and 1B schematically illustrate luminance distribution and inter-block luminance deviation on a screen of a liquid crystal display according to a conventional local dimming method and a peak luminance driving method.

Referring to the drawings, FIG. 1A illustrates an example of a conventional local dimming driving for driving to have a luminance deviation of a backlight between blocks according to an image on one screen. In this case, as shown in FIG. 1B, the peak luminance driving is performed to have a peak luminance higher than 100% of the luminance of a full-white state with respect to a block displaying high luminance in one image. It is characterized by further improving the contrast ratio for the entire image.

That is, in the illustrated example, when comparing the luminance of the blocks corresponding to the V row, the luminance of each block does not exceed 100% in the conventional local dimming drive, but high luminance of 100% or more for a specific block in the peak luminance drive. To drive the backlight.

However, the above-described peak luminance driving method requires a larger amount of current than the conventional local dimming method of the backlight of specific blocks, thereby increasing power consumption when driving the backlight.

In addition, according to the peak luminance driving method, pixels in a block driven at the peak luminance have a problem in that gray scale phenomena, which are difficult to identify when displaying a high gray scale image, occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and reduces power consumption by driving peak luminance in a local dimming liquid crystal display device in which a screen is divided into predetermined logical blocks to control luminance values of each block differently according to an image. It is an object of the present invention to provide a backlight driving circuit and a driving method of a liquid crystal display device.

In addition, another object of the present invention is to provide a backlight driving circuit and a driving method of a liquid crystal display device in which the gray scale phenomenon occurring in the peak luminance driving block when driving the peak luminance of the backlight is improved.

In order to achieve the above object, the dimming control circuit according to a preferred embodiment of the present invention receives a video signal modulated for local dimming operation, and at least one of the logical blocks in which the screen is divided into a plurality of parts is full-white. a peak luminance determiner for generating a peak luminance signal for controlling to have a greater luminance value during full-white driving; A block position calculator for analyzing the modulated video signal to generate a position signal for calculating positions of the blocks on the screen; And a peak luminance adjusting unit configured to compensate for the peak luminance signal in response to the position signal.

The position signal is characterized in that it comprises a value for the separation distance of the block from the reference on the basis of the center of the screen.

The peak luminance adjusting unit may have a value such that a compensation degree of the peak luminance signal is smaller as the separation distance increases.

In order to achieve the above object, a liquid crystal display device to which a dimming control circuit according to a preferred embodiment of the present invention is applied is a local dimming liquid crystal display device which drives a backlight with different luminance among logical blocks in which a plurality of screens are divided. Liquid crystal panels; A gate and a data driver for driving the liquid crystal panel; A timing controller which generates a control signal of the gate and data driver and receives and aligns and converts an image signal from an external system; Generating a peak luminance signal and a dimming signal for modulating the video signal to correspond to the block, and controlling at least one of the blocks to have a greater luminance value during full-white driving; A dimming control circuit for compensating the peak luminance signal according to a position of a peak luminance driving block and applying the same to the dimming signal; A backlight driver for driving the backlight in response to the compensated dimming signal; And a backlight configured to provide light to the liquid crystal panel according to the control of the backlight driver.

The dimming control circuit may include: a peak luminance determiner which receives an image signal modulated for local dimming operation and generates the peak luminance signal; A block position calculator for analyzing the modulated video signal to generate a position signal for calculating positions of the blocks on the screen; And a peak luminance adjusting unit configured to compensate for the peak luminance signal in response to the position signal.

The position signal is characterized in that it comprises a value for the separation distance of the block from the reference on the basis of the exact center on the screen.

The peak luminance adjusting unit may have a value such that a compensation degree of the peak luminance signal is smaller as the separation distance increases.

The dimming control circuit may include: an image analyzer configured to receive and analyze the image signal to define a block, and calculate a local dimming driving luminance value for each block; A data modulator for aligning and modulating the video signal; A dimming determiner configured to generate the dimming signal by one-to-one mapping of the local dimming driving luminance value to a preset dimming curve; And a dimming controller which applies the compensated peak luminance signal to the dimming signal.

The dimming curve may be implemented in the form of a look-up table (LUT).

In order to achieve the above object, the dimming control method according to an embodiment of the present invention, the video signal modulated for the local dimming operation, the full-white at least one of the logical block is divided into a plurality of screens generating a peak luminance signal for controlling to have a greater luminance value during full-white driving; Analyzing the modulated video signal to generate a position signal that calculates the position of each block on the screen; And compensating for the peak luminance signal in response to the position signal.

According to an embodiment of the present invention, by driving the peak luminance value differently corresponding to the position of the logical block on the screen, the LCD not only reduces power consumption but also improves gradation phenomena compared to driving the peak luminance over the entire screen. There is an effect that can provide a backlight driving circuit and a driving method of the device.

1A and 1B schematically illustrate luminance distribution and inter-block luminance deviation on a screen of a liquid crystal display according to a conventional local dimming method and a peak luminance driving method.
2 is a view schematically showing the overall structure of a liquid crystal display according to an embodiment of the present invention.
3 is a diagram showing the structure of a dimming control circuit according to an embodiment of the present invention.
4A is a diagram illustrating an example in which a screen of a liquid crystal display according to an exemplary embodiment of the present invention is divided into predetermined logical blocks, and FIG. 4B illustrates a degree of compensation of peak luminance values according to positions of each block. .
FIG. 5 is a diagram schematically illustrating luminance distribution and inter-block luminance deviation on a screen of a liquid crystal display according to the dimming control method of the present invention.
6 is a diagram illustrating a dimming control method of a liquid crystal display according to an exemplary embodiment of the present invention.

Hereinafter, a backlight driving circuit and a driving method of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

2 is a view schematically showing the overall structure of a liquid crystal display according to an embodiment of the present invention.

As shown, the liquid crystal display according to the exemplary embodiment of the present invention includes a liquid crystal display panel 10, a timing controller 30, a gate driver 50, a data driver 60, a dimming control circuit 70, and a backlight driver. 80 and the backlight 90.

In detail, the liquid crystal display panel 10 includes two transparent substrates bonded to each other by a predetermined distance, and a liquid crystal layer interposed therebetween. Among the two substrates, a plurality of gate lines GL and a plurality of data lines DL vertically cross each other on the lower substrate, and a plurality of pixel regions are defined in a matrix form according to the crossing structure. Each pixel region includes a thin film transistor TFT, which is a switching element, a pixel electrode connected to one electrode of the thin film transistor, a liquid crystal cell Clc, and a storage capacitor Cst.

In addition, a color filter for displaying three primary colors, a black matrix BM and a common electrode for dividing each pixel area are formed on the upper substrate. The common electrode is formed on the upper substrate in a vertical electric field driving mode, that is, a twisted nematic (TN) mode, a vertical alignment (VA) mode, and the like on the lower substrate in the IPS (InPlane Switching) mode, which is a horizontal electric field driving mode. It is formed in parallel with one pixel electrode. In addition, the front and rear surfaces of the liquid crystal display panel 10 are attached with a polarizing plate for polarizing the light entering and exiting.

The timing controller 30 receives a digital data signal DATA and various control signals DCLK, Hsync, and Vsync from an external system 25 that provides a video source, and arranges and converts the various control signals. And a gate control signal GCS and a data control signal DCS to the gate and data drivers 50 and 60, and an image signal DATA to the dimming control circuit 70. In addition, the timing controller 30 receives the image signal DATA ′, which is aligned and converted by the dimming control circuit 70, and supplies it to the data driver 60.

The above-described timing controller 30 receives the above-described signals through an interface with the external system 25, and a low voltage differential signal (LVDS) interface and a TTL interface are used as the interfaces. Such an interface may be configured in a form of a single chip embedded in the timing controller 30.

The gate driver 50 turns on / off the thin film transistors TFTs arranged on the liquid crystal panel 10 in response to the gate control signal GCS input from the timing controller 30. To control.

To this end, the gate driver 50 is composed of a plurality of shift registers to generate a gate driving signal VG, supply the gate driving signal VG to the plurality of gate gate lines GL, and respond to the gate driving signal VG in response to the liquid crystal display panel ( The thin film transistor 10 is turned on / off to allow an image signal supplied from the data driver 60 to be applied to a pixel connected to each thin film transistor TFT.

The gate control signal GCS input to the gate driver 50 may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable (GOE). The gate driver 50 sequentially shifts the GSP according to the GSC among the input gate control signals GCS to sequentially supply the gate driving signals VG to the plurality of gate lines GL. Here, the pulse width of the gate driving signal VG is controlled in accordance with GOE.

The data driver 60 selects reference voltages of the input image signal DATA ′ corresponding to the data control signal DCS input from the timing controller 30, and supplies the selected reference voltage to the liquid crystal display panel 10. By applying it to the pixel, thereby controlling the rotation angle of the liquid crystal molecules.

The data control signal DCS includes a source start pulse SSP, a source shift clock SSC, a source output enable signal, and the like. The image signal DATA 'input from the timing controller 30 is converted into an analog voltage form. Specifically, the data driver 60 latches the image signal DATA ′ input from the timing controller 50 in response to the SSC, and then gate-drive signals to the gate lines GL in response to the SOE signal. The video signal for one horizontal line is supplied to the data line DL every one horizontal period supplied with VG.

At this time, the data driver 60 selects a positive or negative gamma voltage having a predetermined level according to the gray value of the alignment and conversion image signal DATA 'and supplies the selected gamma voltage to each data line DL. .

 The dimming control circuit 70 analyzes the image signal DATA input from the timing controller 30 to determine a backlight luminance value corresponding to each logical block to generate a dimming signal DIM. In addition, the dimming control circuit 70 calculates a degree of luminance reduction of a specific pixel by the dimming signal DIM, and converts the image signal DATA to the data driver 60 in consideration of this. The above-described conversion process of the image signal DATA is to compensate for the luminance reduction caused by the local dimming driving on the liquid crystal side rather than the backlight side, and pixels in one block may display different gradations. This is a process of comparing the amount of light driven by local dimming with the amount of light driven in non-dimming and generating a video signal DATA ′ converted according to the difference. Accordingly, the dimming control circuit 70 adaptively modulates the input image signal DATA.

In addition, the dimming control circuit 70 determines the peak luminance value for each block and applies it to the dimming signal, but the dimming signal (DIM) compensated by setting the degree of the peak luminance value differently according to the relative position of the block on the screen. Create ')

In particular, the dimming control circuit 70 analyzes the input image signal DATA after generating the dimming signal DIM to determine where each block is located on the screen, and is determined from the center of the screen to the outside. Set the peak luminance value smaller and smaller. That is, the dimming control circuit 70 of the present invention is characterized in that the peak luminance value is variable according to the position of the block, not the peak luminance value is determined according to the shape of the image.

The dimming control circuit 70 determines the position of each logical block on the screen, calculates the distance between the center area of the screen and each block, and adjusts the peak luminance value according to the distance. The adjusted peak luminance value is applied to the dimming signal DIM 'and supplied to the backlight driver 80.

This is due to the visual characteristic that the observer obtains an improved contrast ratio when the luminance of the center region of the screen is higher than the luminance of the outer region, and the color is also brighter than before.

A more detailed description of the structure of the dimming control circuit 70 will be described later.

The backlight driver 80 determines the lighting and blinking periods of the backlight according to the duty ratio in response to the corrected dimming signal DIM 'for each logical block input from the dimming control circuit 70. Width Modulation) to drive the backlight. The backlight driver 80 may be implemented as a plurality of inverters for driving each light source divided into a plurality of blocks.

The backlight 90 includes a plurality of light sources, and a plurality of light sources are grouped again to divide the surface light source irradiated to the liquid crystal display panel 10 into logical blocks. The backlight 90 may be implemented as either a direct type or an edge type. In the case of the metering type, it is not easy to divide the screen into predetermined blocks. However, one side light source is provided on each of the X and Y axes of the four sides of the liquid crystal display panel 10, and each row and column line unit is provided. Local dimming can also be implemented by increasing the luminance of the block by controlling the lighting of the light source to overlap the screen. As a light source of the backlight 90, a light emitting diode (LED), which is a point light source that is advantageous for blocking, is preferably used.

In order to increase the efficiency of light emitted from the above-described backlight 90, the optical member 95 is provided on the front surface of the backlight 90 and the rear surface of the liquid crystal display panel 10. A light guide plate and a prism sheet for guiding light emitted from the light source, and a reflecting plate or the like on the rear surface of the backlight 90.

The liquid crystal display device having such a structure can provide an observer with an improved contrast ratio by applying the peak luminance driving method variably according to the position of each block by the dimming control circuit described above. Hereinafter, a structure of a dimming control circuit according to a preferred embodiment of the present invention will be described with reference to the drawings.

3 is a diagram showing the structure of a dimming control circuit according to an embodiment of the present invention.

As illustrated, the dimming control circuit of the present invention includes an image analyzer 110, a dimming determiner 120, a data modulator 130, a peak luminance processor 150, and a dimming controller 170. It includes.

The image analyzer 110 divides a plurality of screens of the LCD panel into virtual logical block units in a matrix form through image signals input from an external system, and analyzes each block to calculate local dimming driving luminance values for each block. Calculate.

The dimming determiner 120 generates a dimming signal DIM by one-to-one mapping of the driving luminance value of each block analyzed by the image analyzer 110 to a preset dimming curve. The dimming curve may be implemented in the form of a look-up table (LUT).

The data modulator 130 may adjust the amount of light at the time of local-dimming and the amount of light at the time of non-dimming in response to the local dimming driving luminance value of each block calculated by the image analyzer 110. In comparison, the video signal DATA is modulated according to the difference to generate the video signal DATA '.

The peak luminance processor 150 generates a peak luminance signal PK for each block in response to the modulated image signal DATA ′ generated by the data modulator 130. The peak luminance signal PK described above is a signal for controlling to have a greater luminance value during full-white driving in which the entire backlight lamp is turned on for a specific block. In addition, the peak luminance processing unit 150 determines a position where each logical block is arranged on the screen in response to the modulated video signal DATA ', and calculates a distance from which each block is separated from the screen center area. The peak luminance value is compensated in proportion to, and the compensated peak luminance signal PK 'is supplied to the dimming controller 170.

To this end, the peak luminance processing unit 150 receives a modulated image signal DATA ′ for local dimming operation, and outputs a peak luminance signal PK to at least one of the plurality of logical blocks. A peak luminance determining unit 152 to generate, a block position calculating unit 154 for generating a position signal BLK for calculating a position of a block corresponding to the peak luminance signal PK on the screen, and a position signal BLK A peak luminance adjusting unit 156 for compensating for the peak luminance signal.

The dimming control unit 170 receives the dimming signal DIM generated by the dimming determination unit 120 and the compensated peak luminance signal PK 'supplied by the peak luminance processing unit PK' and receives the dimming signal DIM. ) Is applied to the compensated peak luminance signal PK 'to generate the compensated dimming signal DIM', and is supplied to the backlight driver 80 of FIG.

According to the above structure, the dimming control circuit of the present invention generates a dimming signal and a peak luminance signal through the input image signal, adjusts the peak luminance signal according to the position of the block, and then adjusts the generated dimming signal to backlight To the driver. Hereinafter, an example of a peak luminance compensation form of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

4A is a diagram illustrating an example in which a screen of a liquid crystal display according to an exemplary embodiment of the present invention is divided into predetermined logical blocks, and FIG. 4B illustrates a degree of compensation of peak luminance values according to positions of each block. .

FIG. 4A is an example of dividing a screen of a liquid crystal display into 6 X 6 blocks (BLK [x, y], x, y is a natural number), and shows a screen of a liquid crystal display divided into 36 logical blocks. have.

According to an exemplary embodiment of the present invention, the peak luminance sphere of the center area of the screen of the blocked LCD, that is, BLK [3,3], BLK [3,4], BLK [4,3], and BLK [4,4] At the same time, the initial peak luminance value is maintained at 100% and the outer area surrounding the center area, that is, BLK [1,1], BLK [2,2], etc., is at least 100% lower than ~ 70%, ~ 40%, etc. Will be driven. Here, the ratio of the peak luminance value of each block is not limited to a specific value, and at least blocks of the outer region may have a smaller peak luminance value than those of the center region.

This is based on the fact that the higher the luminance in the central region of the screen, the more the contrast ratio becomes more prominent and the color is brighter for the viewing image due to the visual characteristics of the person.

Therefore, as shown in FIG. 4B, in the liquid crystal display of the present invention, the peak luminance value of the center region 1A is set to 100%, and then the first outer region 2A is 70% to 80%, and the second is 2%. By setting the outer region 3A to 30% to 40% to compensate for the peak luminance value of each block, the contrast ratio is improved by differently applying the peak luminance value according to the position of the block on the screen.

FIG. 5 is a diagram schematically illustrating luminance distribution and inter-block luminance deviation on a screen of a liquid crystal display according to the dimming control method of the present invention.

1B, which is an example before the peak luminance compensation, the luminance of the block corresponding to the V row is the conventional peak luminance driving, but the liquid crystal display drives the backlight with a high luminance of 100% or more for a specific block. The LCD shows that the center region and the blocks adjacent to the center region are driven at the luminance of 100% or higher peak luminance (C), but the luminance is applied to the edges with lower and lower peak luminance values. Can be. As a result, the number of blocks driven at a peak brightness of 100% or more is smaller than that of the conventional peak brightness driving, thereby reducing the overall power consumption of the liquid crystal display. In addition, as all blocks driven at the peak luminance operate at different luminance, gray level aggregation is also improved.

Hereinafter, a dimming control method of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

6 is a diagram illustrating a dimming control method of a liquid crystal display according to an exemplary embodiment of the present invention. Hereinafter, for more clear description, it will be described with reference to the reference numerals of FIG.

As shown in FIG. 6, the dimming control method of the liquid crystal display according to the present invention includes a data receiving step (S600), a dimming value determination and a data modulation step (S610), a peak luminance value determining step (S620), and a block position calculating step. In operation S630, the peak luminance value adjusting step S640 and the dimming value compensating step S650 are included.

In detail, the data receiving step S600 is a step in which the image analyzer 110 of the dimming control circuit receives an image signal DATA from a timing controller.

In the dimming value determination and data modulation step (S610), the image analyzer 110 divides the screen of the liquid crystal display panel into a plurality of virtual logical block units in a matrix form corresponding to the input image signal DATA. A dimming signal is generated by analyzing each block to calculate a local dimming driving luminance value for each block.

In addition, the data modulator 130 of the dimming control circuit compares the light amount during driving with the local dimming and the light amount during normal driving with respect to the input image signal DATA, and sorts and converts the light according to the difference. DATA ') step.

In the peak luminance value determining step S620, the peak luminance determiner 152 receives the image signal DATA ′ modulated in step S610, and generates a peak luminance signal PK for at least one of the plurality of logical blocks. ) Step.

In the block position calculating step S630, the block position calculator 154 generates a position signal BLK obtained by calculating a position of a block corresponding to the peak luminance signal PK on the screen.

The peak luminance value adjusting step S640 is a step in which the peak luminance adjusting unit 156 compensates the peak luminance signal PK generated in step S620 according to the position signal BLK generated in step S630. Here, the position signal BLK includes a value for the separation distance of each block from the reference with respect to the center of the screen, and the larger the separation distance, the smaller the compensation degree of the peak luminance signal. That is, the peak luminance values of the blocks in the center region are adjusted to have a value greater than the peak luminance values of the blocks in the outer region.

In the dimming value compensating step S650, the dimming control unit 170 compensates for the dimming signal DIM ′ compensated by applying the dimming signal DIM generated in step S610 to the peak luminance signal PK ′ compensated in step S640. It is a step of generating.

According to the above-described steps, the dimming control method of the present invention generates a dimming signal and a peak luminance signal through the input image signal, and adjusts the dimming signal through the peak luminance signal according to the position of the block, thereby adjusting the image of the image. The contrast ratio is improved and power consumption is reduced.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Accordingly, the invention is not to be determined by the embodiments described, but should be determined by equivalents to the claims and the appended claims.

10: liquid crystal panel 25: external system
30: timing controller 50: gate driver
60: data driver 70: dimming control circuit
80: backlight driver 90: backlight
95: optical member

Claims (10)

Peak luminance that receives a modulated video signal for local dimming operation and controls at least one of the logical blocks that divide the screen into a plurality of screens to have a higher luminance value when full-white driving is performed. A peak luminance determiner for generating a signal;
A block position calculator for analyzing the modulated video signal to generate a position signal for calculating positions of the blocks on the screen; And,
Peak luminance adjusting unit for compensating the peak luminance signal corresponding to the position signal
Dimming control circuit comprising a. The method of claim 1,
The position signal,
Dimming control circuit comprising a value for the separation distance of the block from the criterion on the basis of the center of the screen. The method of claim 2,
The peak brightness adjustment unit,
Dimming control circuit, characterized in that the larger the separation distance has a smaller compensation degree of the peak luminance signal. A local dimming liquid crystal display device for driving a backlight with different luminance between logical blocks in which a screen is divided into a plurality of screens.
A liquid crystal panel;
A gate and a data driver for driving the liquid crystal panel;
A timing controller which generates a control signal of the gate and data driver and receives and aligns and converts an image signal from an external system;
Generating a peak luminance signal and a dimming signal for modulating the video signal to correspond to the block, and controlling at least one of the blocks to have a greater luminance value during full-white driving; A dimming control circuit for compensating the peak luminance signal according to a position of a peak luminance driving block and applying the same to the dimming signal;
A backlight driver for driving the backlight in response to the compensated dimming signal; And,
A backlight providing light to the liquid crystal panel according to the control of the backlight driver
And the liquid crystal display device. The method of claim 4, wherein
Wherein the dimming control circuit comprises:
A peak luminance determiner which receives a modulated image signal for local dimming driving and generates the peak luminance signal;
A block position calculator for analyzing the modulated video signal to generate a position signal for calculating positions of the blocks on the screen; And,
Peak luminance adjusting unit for compensating the peak luminance signal corresponding to the position signal
Dimming control circuit comprising a. The method of claim 5, wherein
The position signal,
And a value for a separation distance of the corresponding block from the reference based on the center of the screen. The method of claim 5, wherein
The peak brightness adjustment unit,
And the compensation distance of the peak luminance signal is smaller as the separation distance increases. The method of claim 5, wherein
Wherein the dimming control circuit comprises:
An image analyzing unit configured to receive and analyze the image signal to define a block, and calculate a local dimming driving luminance value for each block;
A data modulator for aligning and modulating the video signal;
A dimming determiner configured to generate the dimming signal by one-to-one mapping of the local dimming driving luminance value to a preset dimming curve; And,
Dimming control unit for applying the compensated peak luminance signal to the dimming signal
Liquid crystal display device further comprising. The method of claim 8,
The dimming curve is a liquid crystal display, characterized in that implemented in the form of a look-up table (LUT). Peak luminance that receives a video signal modulated for local dimming operation and controls at least one of the logical blocks in which the screen is divided into a plurality of pixels to have a higher luminance value than in full-white driving. Generating a signal;
Analyzing the modulated video signal to generate a position signal that calculates the position of each block on the screen; And,
Compensating for the peak luminance signal in response to the position signal;
Dimming control method comprising a.

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