KR101862610B1 - Driving circuit for liquid crystal display device and method for driving the same - Google Patents

Abstract

The present invention is applicable to a driving apparatus of a liquid crystal display apparatus capable of further increasing the local dimming efficiency of a backlight by applying an optimal backlight local dimming value corresponding to brightness characteristics of a display image by a simple calculation process And a method of driving the liquid crystal panel, the liquid crystal panel including a plurality of pixel regions to display an image; A first dimming value is set according to the grayscale average of the image data input for each block corresponding to the divided driving area of the backlight and the second dimming value is updated according to the brightness weight of the image data per block, A timing controller for outputting a plurality of dimming control signals in accordance with a third dimming value of each block by updating the second dimming value for each block to a third dimming value according to a brightness characteristic of an image; And a backlight unit for driving the divided driving areas of the backlight according to the plurality of dimming control signals to irradiate the liquid crystal panel with light for each of the divided driving areas.

Description

TECHNICAL FIELD [0001] The present invention relates to a driving apparatus for a liquid crystal display device and a driving method thereof. BACKGROUND OF THE INVENTION [0002]

The present invention is applicable to a driving apparatus of a liquid crystal display apparatus capable of further increasing the local dimming efficiency of a backlight by applying an optimal backlight local dimming value corresponding to brightness characteristics of a display image by a simple calculation process And a driving method thereof.

BACKGROUND ART Demands for video display devices have been increasing in various forms as an information society has developed. In recent years, a liquid crystal display, a field emission display, a plasma display panel, Various flat panel display devices such as a light emitting display are utilized.

The liquid crystal display device displays a desired image by controlling the amount of light transmitted from a backlight unit through a liquid crystal panel having a plurality of liquid crystal cells arranged in a matrix form.

In recent years, fluorescent lamps have been mainly used as a light source of a backlight unit. However, in recent years, a light emitting diode (LED), which is advantageous in terms of power consumption, weight, ) Is used as the backlight unit.

BACKGROUND ART [0002] In recent years, a local dimming method for dividing a backlight into a plurality of blocks by using a backlight unit using LEDs and controlling brightness characteristics for each divided block according to brightness characteristics of a display image has been proposed . However, in order to apply the local dimming method, in addition to the process of analyzing the brightness characteristics of the image corresponding to the divided blocks, it is necessary to predict and analyze the light distribution of the backlight, or to compensate the pixel data corresponding to each block The process had to be done. Particularly, a higher resolution image quality is required, and a driving frequency is also applied up to 240 Hz, so that the amount of calculation for applying the local dimming has increased. Accordingly, there is a problem that it becomes difficult to apply a backlight local dimming method, such as a more complicated circuit structure for performing complicated operations, to increase manufacturing costs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an image display apparatus and a display apparatus capable of applying an optimal backlight local dimming value corresponding to a brightness characteristic of a display image, The present invention provides a driving apparatus for a liquid crystal display device and a driving method thereof.

According to an aspect of the present invention, there is provided an apparatus for driving a liquid crystal display, including: a liquid crystal panel having a plurality of pixel regions to display an image; A first dimming value is set according to the grayscale average of the image data input for each block corresponding to the divided driving area of the backlight and the second dimming value is updated according to the brightness weight of the image data per block, A timing controller for outputting a plurality of dimming control signals in accordance with a third dimming value of each block by updating the second dimming value for each block to a third dimming value according to a brightness characteristic of an image; And a backlight unit for driving the divided driving areas of the backlight according to the plurality of dimming control signals to irradiate the liquid crystal panel with light for each of the divided driving areas.

Wherein the timing controller comprises: a data alignment unit for aligning the image data input from the outside in accordance with the driving of the liquid crystal panel; a first dimming value corresponding to the extracted average value, And a second dimming value for each block is applied to the first dimming value for each block to update the second dimming value so that the brightness weight of each block is applied to the first dimming value for each block. And a plurality of dimming control signals corresponding to the third dimming values of the respective blocks by updating the third dimming values.

Wherein the image analyzing unit comprises an APL analyzing unit for extracting a gradation average value of the image data for each block and setting and outputting a primary dimming value corresponding to the extracted average value for each block, A weight applying unit for updating and outputting each of the primary dimming values as a secondary dimming value so as to apply brightness weights of image data per block, and a weight applying unit for detecting brightness characteristics of at least one frame, And a dimming curve applying unit for varying a dimming curve to update a second dimming value for each block to a third dimming value to output a plurality of dimming control signals respectively corresponding to the third dimming values of the respective blocks .

The weight application unit histograms the gray level values of the pixels for each of the blocks, divides the gray level values of the pixels into the dark gray level and the bright gray level based on the halftone level, and applies the brightness weight using the following equation,

The pixel p in the above equation represents the number of pixels of a larger or smaller gradation level around the halftone level, so that the weight value is applied to the number of pixels of a larger or smaller gradation around the halftone level .

Wherein the dimming curve application unit histograms the pixel tone values of at least one frame unit to analyze brightness characteristics of at least one frame according to the low, medium, and high gradation distributions of the pixels arranged in the histogram, And the second dimming value for each block is updated to the third dimming value according to the selected dimming curve.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display including a liquid crystal panel having a plurality of pixel regions and displaying an image, The first dimming value is set according to the gradation average of the image data input for each block corresponding to the divided driving region of the light and updated to the second dimming value according to the brightness weight of the image data per block, Outputting a plurality of dimming control signals according to the third dimming value of each block by updating the second dimming value for each block to a third dimming value according to a brightness characteristic of the block; And driving the divided driving areas of the backlight according to the plurality of dimming control signals to irradiate the liquid crystal panel with light for each of the divided driving areas.

Wherein the plurality of dimming control signal outputting steps includes the steps of: arranging the image data input from the outside using the data arranging unit to be suitable for driving the liquid crystal panel; and outputting a gradation average value of the image data for each block using an image analyzing unit The first dimming value corresponding to the extracted average value is set for each block, the second dimming value is updated so that the brightness weight of the image data per block is applied to the first dimming value for each block, And outputting a plurality of dimming control signals corresponding to the third dimming values of the respective blocks by updating the second dimming values of the respective blocks according to the brightness characteristics of the units to the third dimming value.

The plurality of dimming control signal outputting steps may include a step of extracting a gradation average value of the image data for each block by using the APL analyzing unit provided in the image analyzing unit, setting a first dimming value corresponding to the extracted average value for each block, And a weight applying unit provided in the image analyzing unit to apply brightness weights of the image data of each block to the primary dimming values of the respective blocks to adjust the respective primary dimming values to a secondary dimming value And a dimming curve application unit provided in the image analysis unit to detect a brightness characteristic of at least one frame unit and to vary a dimming curve according to detected brightness characteristics of each frame, The plurality of dimming control signals corresponding to the third-order dimming values of the respective blocks by causing the dimming value to be updated to the third- Characterized in that the including the step of outputting.

The driving apparatus and driving method of a liquid crystal display according to an embodiment of the present invention having various technical features as described above can apply an optimal backlight local dimming value corresponding to brightness characteristics of a display image with a simple calculation process have. Accordingly, the present invention can further improve the backlight local dimming efficiency, which can improve the image display quality while reducing the power consumption of the backlight.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram showing a driving apparatus of a liquid crystal display according to an embodiment of the present invention; FIG.
Fig. 2 is a block diagram specifically showing the timing controller shown in Fig. 1. Fig.
3 is a block diagram specifically showing the image analysis unit shown in FIG.
FIG. 4 is a graph for explaining the operation of the APL analysis unit of FIG. 3;
5 is a histogram illustrating the operation of the weight application unit of FIG.
6A to 6C are graphs for explaining the operation of the dimming curve application unit of FIG. 3;
FIGS. 7A to 7C are diagrams for explaining effects of applying first to third dimming values. FIG.

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

1 is a block diagram showing a driving apparatus for a liquid crystal display according to an embodiment of the present invention.

The driving apparatus of the liquid crystal display shown in FIG. 1 includes a liquid crystal panel 2 having a plurality of pixel regions to display an image; A data driver 4 for driving the data lines DL1 to DLm of the liquid crystal panel 2; A gate driver 6 for driving the gate lines GL1 to GLn of the liquid crystal panel 2; A first dimming value is set in accordance with the grayscale average of the video data RGB for each block corresponding to the divided driving area of the backlight 14 and then the second dimming is performed according to the brightness weight of the video data RGB for each block. And updates the secondary dimming value for each block according to the brightness characteristic of at least one frame image to the tertiary dimming value so that the timing for outputting the plurality of dimming control signals Dim in accordance with the tertiary dimming value of each block A controller 8; And a backlight unit 12 for driving the divided driving areas of the backlight 14 according to the plurality of dimming control signals Dim to irradiate the liquid crystal panel 2 with light for each divided driving area. The timing controller 8 arranges the input image data RGB in accordance with the driving of the liquid crystal panel 2 and supplies the image data RGB to the data driver 4 and outputs the synchronizing signals DCLK, Hsync, Vsync, The gate and data drivers GCS and DCS are generated by supplying the gate and data control signals GCS and DCS to the gate and data drivers 6 and 4, 6, 4).

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each sub-pixel (R, G, B) region defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm ), And a liquid crystal capacitor Clc connected to the TFT. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT, and a common electrode facing the pixel electrode and the liquid crystal. The TFT supplies a video signal from each of the data lines DL1 to DLm to the pixel electrode in response to a scan pulse from each of the gate lines GL1 to GLn. The liquid crystal capacitor Clc charges the difference voltage between the video signal supplied to the pixel electrode and the reference common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage to implement the gradation . The storage capacitor Cst is connected in parallel to the liquid crystal capacitor Clc so that the video signal charged in the liquid crystal capacitor Clc is maintained until the next video signal is supplied. The storage capacitor Cst may be formed by overlapping the pixel electrode with the previous gate line with the insulating film interposed therebetween, or the pixel electrode may be formed by overlapping the storage line with the insulating film interposed therebetween.

The data driver 4 receives the image data RGB from the timing controller 8 using the source start pulse SSP and the source shift clock SSC among the data control signal DCS from the timing controller 8. [ Into an analog voltage, that is, a video signal. Specifically, the data driver 4 latches the image data RGB input according to the source shift clock SSC of the data control signal DCS, and then, in response to the source output enable (SOE) signal, And supplies a video signal for one horizontal line to each of the data lines DL1 to DLm for every one horizontal period in which scan pulses are supplied to the data lines GL1 to GLn. At this time, the data driver 4 selects a positive or negative gamma voltage having a predetermined level according to the gray level value of the input image data (RGB), and outputs the selected gamma voltage to each of the data lines DL1 to DLm as a video signal. .

The gate driver 6 sequentially generates scan pulses in response to a gate control signal GCS from the timing controller 8, for example, a gate start pulse GSP and a gate shift clock GSC, The pulse width of the scan pulses is controlled according to the GOE signal. Then, the scan pulses whose pulse widths are controlled are again supplied with the gate-on voltages sequentially to the gate lines GL1 to GLn. Specifically, the gate driver 6 sequentially shifts the gate start pulse GSP from the timing controller 8 in accordance with the gate shift clock GSC to generate a scan pulse sequentially. On the basis of the gate output enable (GOE) signal, the pulse width of the scan pulses is controlled to sequentially supply the gate-on voltages whose pulse widths are controlled to the gate lines GL1 to GLn. On the other hand, the gate-off voltage is supplied during the period when no gate-on voltage is supplied to the gate lines GL1 to GLn.

The timing controller 8 arranges the image data RGB from outside in accordance with the size and resolution of the liquid crystal panel 2 and supplies the image data RGB to the data driver 4. [ At this time, the timing controller 8 divides the sorted image data (Data) into blocks corresponding to the divided driving area of the backlight 14. Then, the gradation average value of each divided block image data RGB is extracted and a primary dimming value corresponding to the extracted average value is set for each block. Thereafter, the timing controller 8 updates the primary dimming value for each block to the secondary dimming value so that the brightness weight of the block-specific image data (RGB) is applied. The second dimming value of each block is updated to the third dimming value according to the brightness characteristic of at least one frame unit, so that a plurality of dimming control signals Dim are outputted according to the third dimming value of each block.

The timing controller 8 generates a gate control signal GCS and a data control signal DCS using synchronous signals DCLK, DE, Hsync and Vsync from the outside, GCS and the data control signal DCS to the gate driver 6 and the data driver 4, respectively. The structure and the driving method of the timing controller 8 of the present invention will be described more specifically with reference to the accompanying drawings.

The backlight unit 12 irradiates the liquid crystal panel 2 with light by driving divided driving areas of the backlight 14 according to a plurality of dimming control signals Dim set by the timing controller 8. [ The backlight unit 12 includes a backlight 14 having a plurality of light sources for generating light and an optical unit for improving the efficiency of light incident from a plurality of light sources and a dimming control signal Dim from the timing controller 8. [ And a backlight control unit 16 for controlling the amount of light supplied to the liquid crystal panel 2 by controlling the ON and OFF times of the divided driving areas of the backlight 14 according to the control signal.

The backlight 14 includes a plurality of light sources connected in series or parallel to each other and generates light by turning on / off the light sources according to at least one driving region according to the driving power supplied to the light sources. In addition, the optical unit diffuses and condenses the incident light from the light source to improve the light efficiency.

The light sources of the backlight 14 may be largely composed of a linear light source, a planar light source, a point light source, or a combination thereof. In recent years, a plurality of light emitting diodes (LEDs) are mainly used as point light sources. Accordingly, an example in which at least one LED group in which a plurality of LEDs are connected in series or in parallel is formed as a light source of the backlight 14 will be described. Each LED group of the backlight 14 may consist of only white LEDs to emit white light, and red, green, and blue LEDs may be combined to emit white light.

Each of the plurality of LED groups may be defined as each driving region and dividedly driven for each region. Depending on the arrangement structure of the LED groups, the backlight 14 may be divided into 4 × 4, 16 × 16, 580 × 640, , n x m (where n x m are mutually the same or different natural numbers), and the like. Each of the driving regions generates light by the driving power source Vled, and the amount of light, that is, the degree of brightness, is controlled by the amount of the LED driving current or the driving current supply period adjusted at the output terminal thereof.

The backlight control unit 16 sets the driving areas of the backlight 14 as divided driving areas of 4 x 4, 16 x 16, 580 x 640, The light amount supplied to the liquid crystal panel 2 is controlled for each of the divided regions by controlling the on and off times of the divided driving regions. Specifically, the backlight control unit 16 generates a pulse width modulation (PWM) signal corresponding to the duty ratio of each dimming control signal Dim input from the timing controller 8. [ Here, the PWM signal is a signal whose on / off period, for example, the high / low period of each LED group is varied according to the duty ratio information of each dimming control signal Dim. In this way, the backlight control unit 16 adjusts the LED driving current output timing outputted from each driving current output terminal of the backlight 14 according to the PWM signal, thereby driving the LEDs in a burst mode do.

2 is a block diagram specifically showing the timing controller shown in Fig.

The timing controller 8 shown in Fig. 2 includes a data arranging unit 11 for arranging image data RGB from outside in accordance with driving of the liquid crystal panel 2 and supplying the data to the data driver 4, The first dimming value corresponding to the extracted average value is set for each block, and then the brightness value of the image data (RGB) for each block is applied to the primary dimming value for each block. And the second dimming value for each block is updated to the third dimming value in accordance with the brightness characteristics of at least one frame unit, so that a plurality of dimming control signals (Dim An image analyzing unit 12 for outputting an image; A gate control signal generator 14 for generating a gate control signal GCS using at least one of synchronizing signals DCLK, DE, Hsync and Vsync from the outside and supplying it to the gate driver 6, And a data control signal generator 16 for generating a data control signal DCS using at least one of the synchronization signals DCLK, Vsync, Hsync and DE and supplying the data control signal DCS to the data driver 4 .

The data sorting unit 11 arranges the image data RGB according to driving of the liquid crystal panel 2 using at least one of the synchronizing signals DCLK, Hsync, Vsync and DE, (Data) to the data driver 4.

The image analyzing unit 12 divides the image data sorted from the data arranging unit 11 into blocks corresponding to the divided driving regions of the backlight 14 and extracts the gradation average value for each block, Is set for each block. After updating the secondary dimming value so that the brightness weight of the image data (RGB) per block is applied to the primary dimming value for each block, the secondary dimming value for each block is set to 3 So that a plurality of dimming control signals (Dim) are outputted in accordance with the third dimming value of each block.

The gate control signal generator 14 generates a gate control signal GOE using at least one of the input synchronizing signals DCLK, DE, Hsync and Vsync, for example, a data enable signal DE and a horizontal synchronizing signal Hsync, GSP and GSC including the signal are generated. Then, the generated gate control signal GCS is supplied to the gate driver 6. The gate control signal GCS is a signal for controlling the driving timing of the gate driver 6.

The data control signal generating unit 16 generates at least one of the input synchronizing signals DCLK, DE, Hsync and Vsync by using the data enable signal DE and the vertical synchronizing signal Vsync, SSC, SSP, and vertical and horizontal POL signals.

3 is a block diagram specifically illustrating the image analysis unit shown in FIG.

The image analyzing unit 26 shown in FIG. 3 extracts the gradation average value APL of the image data RGB for each block and sets a primary dimming value ADim corresponding to the extracted average value APL for each block And an APL analyzing unit 22 for outputting a first dimming value ADim for each block so that brightness values of the RGB data for each block are applied to each primary dimming value ADim for each block, (GDim), and a weight applying unit (24) for detecting brightness characteristics of at least one frame and varying the dimming curves according to the detected brightness characteristics of each frame to obtain a second dimming value (GDim) for each block, And a dimming curve applying unit (26) for updating the third dimming value to output a plurality of dimming control signals (Dim) corresponding to the third dimming values of the respective blocks.

FIG. 4 is a graph for explaining the operation of the APL analyzing unit of FIG. 3, and FIG. 5 is a histogram for explaining the operation of the weight applying unit of FIG. 6A to 6C are graphs for explaining the operation of the dimming curve application unit of FIG. 3. FIG.

Referring to FIGS. 4 to 6C, the APL analyzing unit 22 of FIG. 3 sequentially analyzes the gray level values of the image data RGB for each block and extracts the gray level average value APL of each block. At this time, the APL analyzing unit 22 may extract an average gray level value (gray) by histograms of the gray level values of the pixels for each block, add the gray level values of the pixels for each block sequentially, And the APL analyzing unit 22 may set the first dimming value ADim corresponding to the average gray level value gray thus extracted for each block and output the weighted value to the weight applying unit 24).

The weight applying unit 24 histograms the gradation values of the pixels for each block and divides the gradation values of the pixels into the dark gradation and the light gradation centered on the middle gradation level (for example, 127 gram) Applies the brightness weight.

Here, pixel p represents the number of pixels of a gradation level that is larger or smaller around an intermediate gradation level (for example, 127 grams). Accordingly, the weight applying unit 24 applies the weighting value to the number of pixels of the larger or smaller gradation around the halftone level, so that the brightness characteristic of each block can be applied as the secondary dimming value GDim as much as possible.

The dimming curve application unit 26 detects the overall brightness characteristic in at least one frame unit. At this time, the dimming curve application unit 26 can detect the brightness characteristic of at least one frame according to the histogram distribution by histogramizing the pixel tone values of at least one frame unit. That is, the brightness characteristics of at least one frame are analyzed according to the low, medium, and high gradation distributions of the respective pixels arranged in the histogram. Then, one of the dimming curves (for example, the dimming curves shown in FIGS. 6A to 6C) is selected according to the analyzed brightness characteristics, and the second dimming value GDim ) Is updated to the third dimming value. In this manner, the dimming curve applying unit 26 applies the third dimming value in consideration of the brightness characteristic of at least one frame, and a plurality of dimming control signals (Dim) corresponding to the third dimming values of the respective blocks, To be supplied to the unit (12).

7A to 7C are diagrams for explaining the effect of applying the first to third dimming values.

Specifically, FIG. 7A shows an input image before the first to third dimming values are applied, FIG. 7B shows an image displayed by applying only first and third dimming values, FIG. 7C shows a case where first to third dimming values are applied Displays the displayed image.

When the second dimming value GDim is not used, the brightness of each block is applied as the second dimming value GDim. As shown in FIG. 7B, the dark images of the blocks having the low average gradation value are displayed darker than the original image Problems can arise. However, if the secondary dimming value GDim is applied so that the weight is applied to the number of pixels of a larger or smaller gradation around the halftone level of the image, the brightness characteristic of each block is reflected as much as possible . That is, after the dimming value is set in accordance with the average gradation level for each block, the dimming value is updated so that the brightness characteristic of the image for each block is reflected as much as possible, When the final dimming value is updated by reflecting the brightness characteristic of the whole image and applied to the backlight, the brightness characteristic of each block can be fully reflected by a simple calculation process.

As described above, according to the present invention, an optimal backlight local dimming value corresponding to brightness characteristics of a display image can be applied by a simple calculation process. Accordingly, the present invention can further improve the backlight local dimming efficiency, which can improve the image display quality while reducing the power consumption of the backlight.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (10)

A liquid crystal panel having a plurality of pixel regions to display an image;
A first dimming value is set in accordance with the grayscale average of the video data input for each block corresponding to the divided driving areas of the backlight and a halftone level of the video data for each block is adjusted to be centered And updating the second dimming value for each block by a third dimming value according to a brightness characteristic of at least one frame image to update the second dimming value by applying a brightness weight to the second dimming value, A timing controller for outputting a plurality of dimming control signals in accordance with a tertiary dimming value of the block; And
And a backlight unit for driving the divided driving areas of the backlight according to the plurality of dimming control signals to irradiate the liquid crystal panel with light for each of the divided driving areas. The method according to claim 1,
The timing controller
A data arrangement unit for aligning the image data inputted from the outside in accordance with driving of the liquid crystal panel,
A first dimming value corresponding to the extracted average value is set for each block, and a brightness value of each of the blocks is set to 2 And the second dimming value for each block is updated to the third dimming value in accordance with the brightness characteristic of at least one frame, so that a plurality of dimming control signals corresponding to the third dimming values of the respective blocks are updated And outputting the image data to the liquid crystal display device. 3. The method of claim 2,
The image analysis unit
An APL analyzing unit for extracting a gradation average value of the image data for each block and setting and outputting a primary dimming value corresponding to the extracted average value for each block,
A weight applying unit for applying brightness weights of image data of each block to the primary dimming value for each block and updating and outputting each of the primary dimming values as a secondary dimming value,
The brightness characteristic of at least one frame is detected and the dimming curve is varied according to the detected brightness characteristic of each frame to update the secondary dimming value for each block to the tertiary dimming value, And a dimming curve application unit for outputting a plurality of dimming control signals corresponding to the plurality of dimming control signals. The method of claim 3,
The weight applying unit
Histograms of the tone values of the pixels for each of the blocks,
The brightness gradation is divided into dark gradation and bright gradation based on the middle gradation level, and brightness weight is applied using the following equation,

The pixel p in the above equation represents the number of pixels of a larger or smaller gradation level around the halftone level, so that the weight value is applied to the number of pixels of a larger or smaller gradation around the halftone level And the driving device of the liquid crystal display device. 5. The method of claim 4,
The dimming curve application unit
A method of analyzing brightness characteristics of at least one frame according to a low, medium, and high gradation distribution of each pixel arranged in the histogram by histogramizing pixel tone values of at least one frame,
And a second dimming value for each block is updated to the third dimming value according to the selected dimming curve by selecting one of the plurality of dimming curves according to the analyzed brightness characteristics. Device for driving a device. A driving method of a liquid crystal display device including a liquid crystal panel having a plurality of pixel regions and displaying an image,
A first dimming value is set in accordance with the grayscale average of the video data input for each block corresponding to the divided driving areas of the backlight and a halftone level of the video data for each block is adjusted to be centered And updating the second dimming value for each block by a third dimming value according to a brightness characteristic of at least one frame image to update the second dimming value by applying a brightness weight to the second dimming value, Outputting a plurality of dimming control signals in accordance with the third dimming value of the block; And
And driving the divided driving regions of the backlight according to the plurality of dimming control signals to irradiate the liquid crystal panel with light for each of the divided driving regions. The method according to claim 6,
The plurality of dimming control signal outputting steps
Aligning the image data input from the outside using the data arranging unit to be suitable for driving the liquid crystal panel, and
And a first dimming value corresponding to the extracted average value is set for each block using the image analyzing unit to extract a gray average value of the image data for each block, And a second dimming value for each block is updated to a third dimming value according to a brightness characteristic of at least one frame so that a plurality of And a step of outputting a dimming control signal for the liquid crystal display device. 8. The method of claim 7,
The plurality of dimming control signal outputting steps
A step of extracting a gradation average value of the image data of each block by using the APL analyzing unit provided in the image analyzing unit, setting and outputting a first dimming value corresponding to the extracted average value for each block,
And a weight applying unit provided in the image analyzing unit to apply brightness weights of the image data of each block to the first dimming value for each block to update and output each of the first dimming values as a second dimming value And
The brightness characteristic of at least one frame is detected using the dimming curve application unit provided in the image analysis unit and the dimming curve is varied according to the detected brightness characteristic of each frame so that the secondary dimming value for each block is set to a third dimming value And outputting a plurality of dimming control signals respectively corresponding to the third-order dimming values of the respective blocks. 9. The method of claim 8,
The step of updating each of the primary dimming values with a secondary dimming value
Histograms of the tone values of the pixels for each of the blocks,
The brightness gradation is divided into dark gradation and bright gradation based on the middle gradation level, and brightness weight is applied using the following equation,

The pixel p in the above equation represents the number of pixels of a larger or smaller gradation level around the halftone level, so that the weight value is applied to the number of pixels of a larger or smaller gradation around the halftone level And a driving method of the liquid crystal display device. 10. The method of claim 9,
The step of updating each of the secondary dimming values with a third dimming value
A method of analyzing brightness characteristics of at least one frame according to a low, medium, and high gradation distribution of each pixel arranged in the histogram by histogramizing pixel tone values of at least one frame,
And a second dimming value for each block is updated to the third dimming value according to the selected dimming curve by selecting one of the plurality of dimming curves according to the analyzed brightness characteristics. A method of driving a device.

Images