KR20150075641A - Liquid crystal display device and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and an operating method thereof. The liquid crystal display device increases the response speed of a liquid crystal unit to correct the brightness of a backlight unit in an area with limited response speed of the liquid crystal unit while preventing the degradation of image quality. The liquid crystal display device includes: a liquid crystal panel which includes multiple pixel areas and displays an image; a data driver driving data lines of the liquid crystal panel; a gate driver driving gate lines of the liquid crystal panel; a timing controller which the image data of a previous frame and a current frame for multiple preset division areas and outputs a brightness correction control signal according to the image data determination results of the maximum and minimum grey levels for the division areas while generating the modulation data; and the backlight unit which controls the on and off periods of the light sources of the respective division areas and amplifies or reduces the brightness of the light emitted from the division areas according to the brightness correction control signal for each division area.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device capable of enhancing the display quality of an image by improving the response speed of the liquid crystal to prevent degradation of the image quality while compensating the backlight luminance in the area where the liquid crystal response speed can not be improved, ≪ / RTI >

Generally, a liquid crystal display displays an image by adjusting the light transmittance of liquid crystal cells according to a video signal. An active matrix type liquid crystal display device in which a switching element is formed for each liquid crystal cell is suitable for displaying moving images.

Such a liquid crystal display device is disadvantageous in that the response speed is slow due to inherent characteristics such as viscosity and elasticity of the liquid crystal. In particular, although the liquid crystal response speed of the TN mode (Twisted Nematic Mode) may vary depending on the physical properties of the liquid crystal material and the cell gap, the response speed of the liquid crystal is usually one frame period of the moving picture (National Television Standards Committee: 16.67 ms for NTSC) Is longer. Accordingly, since the voltage charged in the liquid crystal cell proceeds to the next frame before reaching a desired voltage, a motion blurring phenomenon occurs in which blurring of the screen occurs in the moving picture, and the display quality is degraded.

In order to solve the slow response speed of such a liquid crystal display device, US Pat. No. 5,495,265 and PCT International Publication No. WO 99/09967 propose a method of modulating data depending on whether data is changed or not. The proposed conventional technique compensates for the slow response speed of the liquid crystal by the modulation of the data value, thereby alleviating the motion blurring phenomenon in the moving image, thereby displaying an image with a desired color and brightness.

However, according to the proposed conventional technique, the highest and lowest gradation data of the display image can not be compensated or modulated, and the data modulation efficiency is inevitably lowered in the image display areas of the highest and lowest gradations. In addition, conventionally, problems such as a brighter tone or a darker tone appearing as a cluster are displayed with a high tone and a low tone tone.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a liquid crystal display device capable of improving the response speed of a liquid crystal to prevent degradation of image quality, And a method of driving the liquid crystal display device.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal panel having a plurality of pixel regions to display an image; A data driver for driving data lines of the liquid crystal panel; A gate driver for driving gate lines of the liquid crystal panel; The modulation data is generated by comparing the video data of the previous frame and the video data of the current frame for each of a plurality of predetermined division areas and the luminance compensation control signal is output in accordance with the video data detection result of the highest and lowest gray levels A timing controller; (ON) or off (OFF) period of the light sources for each of the divided regions of the backlight and amplifying or attenuating the light emission luminance of the corresponding divided regions according to the luminance compensation control signal for each of the divided regions, And a light unit.

Wherein the timing controller comprises: a high-speed driving circuit for comparing the video data of the previous frame with the video data of the current frame for each of a plurality of predetermined divided areas, and generating the modulated data according to the pixel- And a compensation control signal generator for detecting the highest and lowest gradation image data for each of the division areas and for outputting the luminance compensation control signal for each of the division areas according to the number of detected image data of the highest and lowest gradations .

Wherein the compensation control signal generator includes at least one counter to detect the maximum and minimum gradation image data counts for each of the division areas, and compares the detected number of each of the highest and lowest gradation image data with a preset reference number Compensating control signal for amplifying or attenuating the brightness of the backlight region corresponding to each of the divided regions according to the ratio of the detected maximum and minimum gradation image data to the number of the image data for each of the divided regions, And outputting the output signal.

Wherein the backlight unit is divided into a plurality of divided regions corresponding to the divided regions of the liquid crystal panel and a plurality of light sources for generating light for each of the divided regions are arranged; And a control unit for controlling the ON or OFF periods of the light sources for the respective driving channels of the backlight according to the duty ratio of the dimming control signal or the pulse width modulation signal supplied from the external system or the timing controller, And a backlight control unit that amplifies or attenuates the brightness of each of the divided regions and drives the backlight unit.

Wherein the backlight control unit includes a driving power source for supplying driving power to the light sources of each of the divided regions of the backlight and a driving power source for driving the light sources for the respective divided areas according to a duty ratio of the dimming control signal or the pulse width modulation signal, And a first to an n-th driving ICs for supplying driving signals and amplifying or attenuating a current amount of at least one light source driving signal among the light source driving signals supplied to the light sources for the respective divided regions according to the luminance compensation control signal, And a control unit.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display device including driving a gate and a data line of a liquid crystal panel having a plurality of pixel regions to display an image, The modulation data is generated by comparing the video data of the previous frame and the video data of the current frame for each of a plurality of predetermined division areas and the luminance compensation control signal is output in accordance with the video data detection result of the highest and lowest gray levels ; (ON) or off (OFF) periods of the light sources for each of the divided regions of the backlight, and driving or amplifying the light emission luminance of the corresponding divided regions according to the luminance compensation control signal for each of the divided regions .

Wherein the step of generating the modulation data and outputting the luminance compensation control signal comprises the steps of: comparing the image data of the previous frame and the image data of the current frame by a plurality of predetermined divided areas; Generating modulation data according to a result of the comparison, and detecting the highest and lowest gradation image data for each of the division areas, and controlling the luminance compensation control for each of the division areas according to the number of detected image data of the highest and lowest gradations, And outputting a signal.

Wherein the step of outputting the luminance compensation control signal comprises the steps of: detecting the maximum and minimum gradation image data counts for each of the divided regions using at least one counter; The brightness of the backlight region corresponding to each of the divided regions is amplified or attenuated in accordance with the comparison result of the reference number or the ratio of the detected maximum and minimum gradation image data counts to the number of image data for each of the divided regions And generating and outputting a luminance compensation control signal.

The step of amplifying or attenuating the light emission luminance of the divided regions may include arranging a plurality of light sources for generating light for each of the plurality of divided regions corresponding to the divided regions of the liquid crystal panel. Controlling a lighting period or a lighting period of light sources for each driving channel of the backlight according to a duty ratio of a dimming control signal or a pulse width modulation signal supplied from an external system or the timing controller; And amplifying or attenuating the brightness of each of the divided areas and driving the brightness of the divided areas.

The step of amplifying or attenuating the light emission luminance of the divided regions may include supplying driving power to the light sources of each of the divided regions of the backlight and driving the light sources according to the duty ratio of the dimming control signal or the pulse width modulation signal, Supplying a light source driving signal to each of the light sources according to each region, and supplying at least one of the light source driving signals supplied to the light sources according to each of the divided regions according to the luminance compensation control signal by amplifying or attenuating the amount of the light source driving signal The method comprising the steps of:

In the liquid crystal display device and the driving method thereof according to the embodiment of the present invention, the response speed of the liquid crystal is improved to prevent degradation of the image quality, and in the area where the liquid crystal response speed can not be improved, The display quality of the image can be improved.

1 is a circuit diagram showing a liquid crystal display device according to an embodiment of the present invention;
Fig. 2 is a block diagram specifically showing the timing controller shown in Fig. 1. Fig.
3 is a block diagram specifically showing the high-speed driving circuit and the compensation control signal generator shown in FIG. 2;
FIG. 4 is a table diagram for explaining a method of selecting and generating modulated data of the look-up table shown in FIG. 3; FIG.
5 is a sectional view showing an example of setting a divided area of the liquid crystal panel shown in Fig.
Fig. 6 is a block diagram specifically showing the backlight unit of Fig. 1; Fig.
FIG. 7 is a view for explaining a brightness control method of at least one divided area of the backlight shown in FIG. 6; FIG.
FIG. 8 is another diagram for explaining a brightness control method of at least one divided area of the backlight shown in FIG. 6; FIG.

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

1 is a circuit diagram showing a liquid crystal display device according to an embodiment of the present invention.

The liquid crystal display device 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 22; (MData) by comparing the video data of the previous frame and the video data of the current frame for each of a plurality of predetermined divided areas, and generates modulation data (MData) A timing controller 8 for outputting a signal BU.BD; (ON) / off (OFF) periods of the light sources for each of the divided regions of the backlight 14 and the backlight 14, and controls the light emission luminance of the corresponding divided regions according to the luminance compensation control signal BU.BD for each of the divided regions And a backlight unit 12 driven by amplification or attenuation.

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each pixel region defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, And a capacitor Clc. 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 data 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 data signal supplied to the pixel electrode and the 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. The storage capacitor Cst is connected in parallel to the liquid crystal capacitor Clc so that the voltage charged in the liquid crystal capacitor Clc is maintained until the next data signal is supplied. The storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line and the insulating film interposed therebetween. Alternatively, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating film interposed therebetween.

The data driver 4 receives a data control signal DCS from the timing controller 8, for example, a source start pulse SSP, a source shift clock SSC, a source output enable The modulation data MData aligned from the timing controller 8 is modulated into an analog voltage, that is, a video signal, using a SOE (Source Output Enable) signal or the like. Specifically, the data driver 4 latches the image data VData input in accordance with the SSC, and then, in response to the SOE signal, applies a scan pulse to each of the gate lines GL1 to GLn, To each of the data lines DL1 to DLm. 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 modulation data MData and supplies the selected gamma voltage to each of the data lines DL1 to DLm as a video signal do.

The gate driver 6 outputs a gate control signal GCS from the timing controller 8, for example, a gate start pulse GSP, a gate shift clock GSC, a gate output enable Sequentially generates scan pulses in response to a gate output enable (GOE) signal, and sequentially supplies the scan pulses to the gate lines GL1 to GLn. In other words, the gate driver 6 shifts the GSP from the timing controller 8 according to the GSC to sequentially supply a scan pulse, for example, a gate-on voltage to the gate lines GL1 to GLn. Then, the gate-off voltage is supplied during the period when the gate-on voltage is not supplied to the gate lines GL1 to GLn. Here, the gate driver 6 controls the pulse width of the scan pulse in accordance with the GOE signal.

The timing controller 8 compares the video data of the previous frame with the video data of the current frame for each of a plurality of predetermined divided areas, and generates the modulation data (MData) according to the comparison result of the video data. Then, the luminance compensation control signal BU.BD is outputted for each of the divided regions according to the image data detection results of the highest and lowest gradations of the respective divided regions. Specifically, the timing controller 8 stores image data (RGB) input from an external graphics system or the like in units of frames, and compares the image data of the previous frame with the image data of the current frame on a plurality of predetermined divided areas . Subsequently, the modulated data MData is generated so as to modulate the tone values in accordance with the pixel-by-pixel image data comparison result of each divided area, and the modulated data MData is aligned so as to be suitable for driving the liquid crystal panel 2, 4).

Further, the timing controller 8 detects the highest and lowest gradation image data for each of the divided areas, and outputs the luminance compensation control signal BU.BD for each of the divided areas according to the number of detected image data of the highest and lowest gradations .

In addition, 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, And controls the driver 26. The dimming control signal Dim and the pulse width modulation signal PWM are generated using at least one of the synchronization signals according to the brightness and luminance information of the aligned modulation data MData, 12 to control the backlight unit 12 as well. On the other hand, the dimming control signal (Dim) or the pulse width modulation signal) is generated separately from an external system such as a graphics card and supplied to the backlight unit (12). Here, the dimming control signal Dim may be a digital signal for setting a duty ratio which is a ratio of a driving current supply period (Dimming Time), or may be a pulse width modulation signal PWM having a duty ratio set.

 The backlight unit 12 is controlled in accordance with the duty ratio of the dimming control signal Dim or the pulse width modulation (PWM) signal from the external system or the timing controller 8, (ON) / off (OFF) period of the individual light sources, and drives or amplifies the light emission luminance of the corresponding divided areas according to the luminance compensation control signal BU.BD for each of the divided areas.

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

The timing controller 8 shown in FIG. 2 compares the image data of the previous frame with the image data of the current frame for each of a plurality of predetermined divided areas and outputs the modulated data MData A high-speed drive circuit portion 21 for generating a high-speed drive signal; A data arrangement unit (22) for arranging and outputting modulated data in accordance with driving of the liquid crystal panel (2); A compensation control signal generator 23 for detecting video data of the highest and lowest gradations for each of the divided regions and outputting a luminance compensation control signal BU.BD for each of the divided regions according to the number of detected video data of the highest and lowest gradations, ; A data control signal generator 24 for generating a data control signal DCS to control the driving timing of the data driver 4; And a gate control signal generator 25 for generating a gate control signal GCS and controlling the driving timing of the gate driver 6. [

The high-speed driving circuit 21 divides the image data of the previous frame and the image data of the current frame by a plurality of predetermined division areas, and compares the image data of each pixel of each division area. And sequentially supplies the modulated data MData to the data arranging unit 22 and the compensation control signal generating unit 23 according to the comparison result of the image data for each pixel. The data sorting unit 22 arranges the modulated data MData sequentially inputted according to the resolution and the driving frequency of the liquid crystal panel 2 and supplies the modulated data to the data driver 4.

The compensation control signal generating unit 23 detects the highest and lowest gradation image data for each of the divided areas, and performs luminance compensation control for each of the divided areas according to the number of detected video data of the highest and lowest gradations, And generates and outputs the signal BU.BD. Here, in the case of 8-bit image data, the image data of the highest and lowest gradations can be data of 0 gradation at the lowest and data of 255 gradations at the highest. In the case of 10-bit video data, the video data of the highest and lowest gradations can be data of the lowest 0 gradations and data of 1023 gradations maximum.

3 is a block diagram specifically illustrating the high-speed driving circuit and the compensation control signal generator shown in FIG.

The high-speed driving circuit 11 shown in FIG. 3 includes a frame memory 26 for storing image data RGB inputted from the outside in at least one frame unit and outputting stored image data RGB as previous data Fn-1 Up table 27 for comparing the previous data Fn-1 from the frame memory 11 with the currently input image data Fn and selectively outputting the modulated data MData corresponding thereto do. The high-speed driving circuit 11 configured as described above may be configured separately from the timing controller 8 and may supply the modulation data MData to the data alignment unit 12 of the timing controller 8. [ However, in the present invention, an example in which the high-speed driving circuit 11 is incorporated in the timing controller 8 will be described for the sake of convenience.

The frame memory 26 stores the input image data RGB in at least one frame unit. Then, the stored image data (RGB) is sequentially supplied to the first look-up table 27 with the previous data Fn-1.

FIG. 4 is a table diagram for explaining a method of selecting and generating modulated data in the look-up table shown in FIG.

4, the look-up table 27 sequentially compares the previous data Fn-1 sequentially supplied from the frame memory 26 with the currently input image data Fn, that is, the current data Fn do. Then, the modulated data MData corresponding to the compared result is selected and supplied to the data sorting unit 12. Here, the modulation data (MData) is data in which the gray level value of the current data (Fn) is modulated so that the liquid crystal can be driven at high speed. 4, when the 10-bit image data is displayed, the maximum and minimum gradation data (0-gradation, 0-gradation) of the image is obtained by using the look-up table 27 in which the 10-bit modulated image data (MData) 1023 gradations) can not be compensated or modulated. Thus, in the present invention, the maximum and minimum gradation data (0 gradation, 1023 gradation) compensate for brightness using the brightness of the backlight.

5 is a sectional view showing an example of setting a divided area of the liquid crystal panel shown in FIG.

The compensation control signal generator 23 includes at least one counter 23 to detect the number of video data of the highest and lowest gradations for each of the divided areas, and detects the number of video data of the highest and lowest gradations, A luminance compensation control signal for amplifying or attenuating the brightness of the backlight region corresponding to each divided region according to the comparison result of the reference number or the ratio of the number of the highest and lowest gradation image data detected relative to the number of image data per divided region BU.BD).

The minimum and maximum gradation video data detected by the compensation control signal generator 23 may be the lowest 0 gradation data and the maximum 1023 gradation data in the case of 10 bit video data. Accordingly, the compensation control signal generating unit 23 detects the minimum 0 gradation data and the maximum number of 1023 gradation data for each of the divided regions using the self-contained counter 23 or the like. When the detected number of the maximum 1023 gradation data per division area is greater than or greater than a preset reference number, a compensation control signal (BU) for amplifying the brightness of the backlight area corresponding to the divided area is generated and output do. When the lowest 0 gradation data detection count is larger or larger than the preset reference count for each of the detected divided areas, a compensation control signal BD for attenuating the brightness of the backlight area corresponding to the divided area is generated and output do.

Alternatively, if the ratio of the maximum number of detected 1023 gradation data to the total number of image data for each division area is equal to or greater than a predetermined ratio (for example, 50%), the compensation control signal generator 23 may correspond to the corresponding division area And generate and output a compensation control signal BU for amplifying the brightness of the backlight region. If the ratio of the detected lowest 0 gradation data detection number to the total number of image data for each of the divided regions is equal to or greater than a preset ratio (for example, 50%), the brightness of the backlight region corresponding to the divided region is attenuated And generate and output a compensation control signal BD for the output signal.

6 is a block diagram specifically showing the backlight unit of FIG.

The backlight unit 12 of Fig. 6 is divided into a plurality of divided regions corresponding to the divided regions of the liquid crystal panel, and a plurality of light sources (for example, LED arrays 38) Backlight 14; ON / OFF of the LED arrays for each driving channel of the backlight 14 according to the duty ratio of the dimming control signal Dim and the pulse width modulation signal PWM supplied from the external system or the timing controller 8. [ And a backlight control unit 16 for controlling the OFF period and driving the brightness by amplifying or attenuating the brightness for each of the divided regions according to the luminance compensation control signal BU.BD.

The backlight 14 includes a plurality of LED arrays 38 in which a plurality of LEDs are connected to each other in series or in parallel and emit the LED arrays according to a driving power source Vled supplied to each of the LED arrays 38 (ON) to generate light. Each LED array 38 is divided and arranged for each of the divided regions so as to correspond to the divided regions of the liquid crystal panel. Each of the LED arrays of the backlight 14 may include only white LEDs to emit white light, and red, green, and blue LEDs may be combined to emit white light.

The plurality of LED arrays generate light by the driving power source Vled and are driven by the LED driving signal Ipwmn of the LED driving current amount and the driving current supply period (Dimming Time) supplied to the driving channels of the respective output stages, , The degree of brightness is controlled. Each of the transistors Tr1 to Trm may be formed in the driving channels of the respective output stages. In this case, the brightness of each LED array 38 is controlled by the LED driving signals Ipwm1 to Ipwmn supplied to the transistors Tr1 to Trm of the respective driving channels.

The backlight control unit 16 controls the ON / OFF periods of the LED arrays for each driving channel in units of frame periods according to the duty ratio of the dimming control signal Dim and the pulse width modulation signal PWM do. In addition, the backlight control unit 16 amplifies or attenuates the brightness for each of the divided regions in response to the luminance compensation control signals BU and BD, and is driven.

The backlight control unit 16 includes a driving power source generating unit 32 for supplying a driving power source Vled to the light sources of each of the divided regions of the backlight 14 and a dimming control signal Dim or a pulse width modulation signal PWM And supplies the light source driving signals Ipwm1 to Ipwmn to the respective light sources according to the duty ratios of the respective divided regions according to the duty ratio of each of the divided regions, And first to n-th driving ICs 35 and 36 for amplifying or attenuating the amount of at least one light source driving signal among the driving signals Ipwm1 to Ipwmn.

In addition, the backlight control unit 16 generates IC driving power necessary for driving the first to the n-th driving ICs 25 and 26 and generates IC driving power for supplying the IC driving power to the first to nth driving ICs 35 and 36 (34); And at least one feedback current (Vf1 to Vfn) fed back to the first to the n-th driving ICs (35, 36) in response to the luminance compensation control signals (BU, BD) (37).

The driving power source generating unit 32 may simultaneously or sequentially generate a plurality of light sources included in the backlight 14, that is, a driving power source Vled suitable for driving the LED arrays 38, To each of them simultaneously or sequentially.

Each of the first to n-th driving ICs 25 and 26 receives the pulse width modulation signal PWM directly from the external system or the timing controller 8. When the dimming control signal Dim is input, the dimming control signal Dim The pulse width modulation signal PWM may be generated so as to correspond to the duty ratio of the pulse width modulation signal PWM. Thus, each of the first to n-th driving ICs 25 and 26 adjusts output timing of the LED driving signals Ipwm1 to Ipwmn of the LED array 38 according to the pulse width modulation signal PWM, The LED arrays are turned on (ON) / off (OFF) in the burst mode (Burst Mode).

Each of the first to n < th > driving ICs 25 and 26 is driven by at least one of the light source driving signals Ipwm1 to Ipwmn supplied to the light sources of the respective divided regions according to the luminance compensation control signals BU and BD The amount of current of the signal can be amplified or attenuated and supplied.

When each of the first to n < th > driving ICs 25 and 26 receives the luminance compensation control signal BU to amplify the brightness of one of the divided regions, the brightness of the corresponding divided region is amplified And amplifies and supplies the amount of the light source driving signal IPwm. On the other hand, when the luminance compensation control signal BD is input to attenuate the brightness of any one of the divided regions, the amount of the light source driving signal IPwm of the corresponding divided region can be reduced and supplied so that the brightness of the corresponding divided region is attenuated.

The current control section 37 amplifies or attenuates at least one feedback current among the feedback currents Vf1 to Vfn fed back to the first to nth driving ICs 35 and 36 in response to the luminance compensation control signals BU and BD . When the feedback current fed back from the light sources of any one of the divided regions is amplified or attenuated, the current amount of the light source driving signal IPwm is amplified or attenuated through the driving IC to the corresponding divided region.

Accordingly, when the luminance compensation control signal BU is inputted to amplify the brightness of one of the divided regions, the current control unit 37 outputs the feedback current Vf ) Is attenuated and supplied. When the feedback current (Vf) of the corresponding divided region is attenuated in accordance with the luminance compensation control signal (BU), the current amount of the light source driving signal (IPwm) is amplified and supplied to the corresponding divided region through the driving IC. . On the other hand, when the luminance compensation control signal BU is input to attenuate the brightness of one of the divided regions, the feedback current Vf fed back from the corresponding divided region is amplified and supplied . When the feedback current Vf of the corresponding divided region is amplified in accordance with the luminance compensation control signal BU, the amount of current of the light source driving signal IPwm is supplied to the corresponding divided region through the driving IC, Can be lowered.

FIG. 7 is a view for explaining a brightness control method of at least one divided area of the backlight shown in FIG. 6. FIG. Table 1 below sequentially shows the brightness control method of at least one divided area as shown in Fig.

[Table 1]

Referring to Table 1 and FIG. 7, each of the first to n-th driving ICs 25 and 26 and the current control portion 37 are supplied for each of the divided regions when the luminance compensation control signals BU and BD are input The amount of current of at least one light source driving signal among the light source driving signals Ipwm1 to Ipwmn may be maintained or increased or decreased in units of a predetermined frame period.

For example, when each of the first to n < th > driving ICs 25 and 26 receives the luminance compensation control signal BU to amplify the brightness of one of the divided regions, The amount of current of the light source driving signal IPwm of the divided region can be amplified and supplied for three frame periods to maintain the amplified state. Alternatively, when each of the first to n < th > driving ICs 25 and 26 receives the luminance compensation control signal BU to amplify the brightness of one of the divided regions, The amount of current of the light source driving signal IPwm of the corresponding divided region can be supplied so that it is reduced to the state before amplification for the remaining two frame periods.

Meanwhile, when the luminance control signal BU is input to amplify the brightness of one of the divided regions, the current controller 37 controls the current corresponding to the brightness of the corresponding divided region to remain amplified during the three- The feedback current Vf of the divided area can be attenuated and supplied to the driving IC. The feedback current (Vf) of the divided region can be increased after attenuation so that the brightness of the divided region is amplified for one frame period and then reduced to the state before amplification for the remaining two frame periods.

8 is another diagram for explaining the brightness control method of at least one divided area of the backlight shown in Fig. The following Table 2 sequentially shows the brightness control method of at least one divided area as shown in FIG.

[Table 2]

Referring to Table 2 and FIG. 8, each of the first to n-th driving ICs 25 and 26 and the current control unit 37 is supplied for each of the divided regions when the luminance compensation control signals BU and BD are input The amount of current of at least one light source driving signal among the light source driving signals Ipwm1 to Ipwmn may be maintained or decreased in units of a predetermined frame period.

For example, when each of the first to n < th > driving ICs 25 and 26 receives the luminance compensation control signal BU to attenuate the brightness of one of the divided regions, The amount of current of the light source driving signal IPwm of the corresponding divided area can be supplied by attenuating the current for three frame periods so as to maintain the brightness of the divided area. Alternatively, each of the first to n < th > driving ICs 25 and 26 may be configured so that the brightness of the corresponding divided area is attenuated for one frame period, (IPwm) can be supplied.

Meanwhile, when the luminance control signal BU is input so as to attenuate the brightness of one of the divided areas, the current controller 37 controls the current corresponding to the corresponding divided area to maintain the brightness of the corresponding divided area during the three- The feedback current Vf of the divided area can be amplified and supplied to the driving IC. The feedback current (Vf) of the divided region may be amplified and then lowered again so that the brightness of the corresponding divided region is attenuated for one frame period and then increased to a state before attenuation for the remaining two frame periods.

As described above, the liquid crystal display device and the driving method thereof according to the embodiment of the present invention can improve the response speed of the liquid crystal by the modulated data generation method using the high-speed driving circuit, thereby preventing the deterioration of the image quality. In addition, backlight luminance compensation is performed in a region where the liquid crystal response speed can not be improved, that is, in a divided region where a large number of image data of the lowest and highest grayscales are distributed, thereby improving the display quality of an image.

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.

2: liquid crystal panel 4: data driver
6: Gate driver 8: Timing controller
12: Backlight unit 14: Backlight
16: back light control unit 32: driving power source generating unit
34: IC power generation unit 35: first drive IC
36: n-th driving IC 38: LED array

Claims (10)

A liquid crystal panel having a plurality of pixel regions to display an image;
A data driver for driving data lines of the liquid crystal panel;
A gate driver for driving gate lines of the liquid crystal panel;
The modulation data is generated by comparing the video data of the previous frame and the video data of the current frame for each of a plurality of predetermined division areas and the luminance compensation control signal is output in accordance with the video data detection result of the highest and lowest gray levels A timing controller; And
(ON) or off (OFF) period of light sources for each of the divided regions of the backlight and amplifies or attenuates the light emission luminance of the corresponding divided regions according to the luminance compensation control signal for each of the divided regions, And a liquid crystal display unit. The method according to claim 1,
The timing controller
A high-speed driving circuit section for comparing the video data of the previous frame with the video data of the current frame for each of a plurality of predetermined divided areas, and generating the modulated data according to pixel-by-pixel data comparison results of the divided areas;
And a compensation control signal generator for detecting the highest and lowest gradation image data for each of the division areas and outputting the luminance compensation control signal for each of the division areas according to the number of detected image data of the highest and lowest gradations . 3. The method of claim 2,
The compensation control signal generator
At least one counter is provided to detect the maximum number of video data and the minimum number of video data for each of the divided areas,
And a ratio of the number of detected maximum and minimum gradation video data to the number of preset reference number or the ratio of the number of detected maximum and minimum gradation video data to the number of video data for each divided area, And generates and outputs the luminance compensation control signal for amplifying or attenuating the brightness of the corresponding backlight region. The method of claim 3,
The backlight unit
A backlight which is divided into a plurality of divided regions corresponding to the divided regions of the liquid crystal panel and in which a plurality of light sources for emitting light for each of the divided regions are arranged; And
And controlling the ON or OFF periods of the light sources for the respective driving channels of the backlight according to a duty ratio of the dimming control signal or the pulse width modulation signal supplied from the external system or the timing controller, And a backlight control unit for driving each of the divided regions by amplifying or attenuating brightness. 5. The method of claim 4,
The backlight control unit
A driving power source for supplying driving power to the light sources of each of the divided regions of the backlight and a light source driving signal for the light sources for each of the divided regions according to a duty ratio of the dimming control signal or the pulse width modulation signal, together,
And first to n-th driving ICs for amplifying or attenuating the amount of at least one light source driving signal among the light source driving signals supplied to the light sources for each of the divisional regions according to the luminance compensation control signal. Liquid crystal display device. Driving gates and data lines of a liquid crystal panel having a plurality of pixel regions to display an image;
The modulation data is generated by comparing the video data of the previous frame and the video data of the current frame for each of a plurality of predetermined division areas and the luminance compensation control signal is output in accordance with the video data detection result of the highest and lowest gray levels ; And
Controlling the ON or OFF period of the light sources for each of the divided regions of the backlight and driving or amplifying the light emission luminance of the corresponding divided regions according to the luminance compensation control signal for each of the divided regions, And a driving method of the liquid crystal display device. The method according to claim 6,
The step of generating the modulation data and outputting the luminance compensation control signal
Comparing the image data of the previous frame with the image data of the current frame for each of a plurality of predetermined divided areas and generating the modulated data according to the comparison result of the image data of each of the divided areas;
And outputting the luminance compensation control signal for each of the divided areas in accordance with the number of detected image data of the highest and lowest gradations. A method of driving a device. 8. The method of claim 7,
The luminance compensation control signal output step
Detecting each of the maximum and minimum gradation image data counts for each of the divided regions using at least one counter, and
And a ratio of the number of detected maximum and minimum gradation video data to the number of preset reference number or the ratio of the number of detected maximum and minimum gradation video data to the number of video data for each divided area, And generating and outputting the luminance compensation control signal for amplifying or attenuating the brightness of the corresponding backlight region. 9. The method of claim 8,
The step of amplifying or attenuating the emission luminance of the divided regions
Disposing a plurality of light sources for generating light for each of a plurality of divided regions corresponding to the divided regions of the liquid crystal panel;
Controlling the light sources or the light-off periods of the respective light sources of the backlight according to the duty ratio of the dimming control signal or the pulse width modulation signal supplied from the external system or the timing controller, and
And amplifying or attenuating brightness of each of the divided regions according to the luminance compensation control signal to drive the liquid crystal display device. 10. The method of claim 9,
The step of amplifying or attenuating the emission luminance of the divided regions
Supplying driving power to the light sources of each of the divided regions of the backlight,
Supplying a light source driving signal to each of the light sources for each of the divided regions according to a duty ratio of the dimming control signal or the pulse width modulation signal;
And amplifying or attenuating a current amount of at least one light source driving signal among the light source driving signals supplied to the light sources according to each of the division regions according to the luminance compensation control signal.

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