KR102126541B1 - Liquid crystal display device and driving method thereof - Google Patents

Abstract

The present invention improves the response speed of a liquid crystal to prevent deterioration of image quality, but compensates for backlight luminance in areas where the response speed of the liquid crystal cannot be improved. A method comprising: a liquid crystal panel having a plurality of pixel areas to display an image; A data driver driving data lines of the liquid crystal panel; A gate driver driving gate lines of the liquid crystal panel; Compares the image data of the previous frame with the image data of the current frame for each of a plurality of preset division areas, and generates modulation data, and outputs a luminance compensation control signal according to the detection result of the highest and lowest gradation image data for each division area. Timing controller; And controlling the lighting (ON) or off (OFF) period of the light sources for each divided region of the backlight, and driving the bag by amplifying or attenuating the luminance of the corresponding divided regions according to the luminance compensation control signal for each divided region. It is characterized by having a light unit.

Description

Liquid crystal display device and its driving method{LIQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD THEREOF}

The present invention improves the response speed of a liquid crystal to prevent deterioration of image quality, but compensates for backlight luminance in areas where the response speed of the liquid crystal cannot be improved. It's about how.

Typically, a liquid crystal display (LCD) displays an image by adjusting 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 a moving picture.

Such a liquid crystal display device has a disadvantage that a response speed is slow due to characteristics such as inherent viscosity and elasticity of the liquid crystal. Particularly, the response speed of the liquid crystal in the TN mode (Twisted Nematic Mode) may vary depending on the physical properties of the liquid crystal material and the cell gap, but in general, the response speed of the liquid crystal is one frame period of the video (National Television Standards Committee: 16.67 ms for NTSC) Longer than Accordingly, since the voltage charged in the liquid crystal cell proceeds to the next frame before reaching the desired voltage, a motion blurring phenomenon in which a screen is blurred in a video appears and the display quality deteriorates.

In order to solve the slow response speed of such a liquid crystal display, US Patent No. 5,495,265 and PCT International Publication No. WO 99/09967 have proposed a method for modulating data according to whether data is changed. The proposed prior art compensates for the slow response speed of the liquid crystal by modulating the data value, thereby reducing motion blur in a moving image and displaying an image with a desired color and luminance.

However, the proposed prior art cannot compensate or modulate the highest and lowest grayscale data of the display image, and thus the data modulation efficiency inevitably decreases in the image display area of the highest and lowest grayscale. In addition, in the related art, problems such as grayscales appearing brighter or darker as a result of high- and low-gradation images being displayed.

The present invention is to solve the above problems, to improve the response speed of the liquid crystal to prevent the image quality degradation, while improving the response speed of the liquid crystal in the region that can not improve the brightness of the image by making the compensation of the display image quality An object of the present invention is to provide a liquid crystal display device and a driving method thereof.

A liquid crystal display device according to an embodiment of the present invention for achieving the above object has a plurality of pixel areas to display an image; A data driver driving data lines of the liquid crystal panel; A gate driver driving gate lines of the liquid crystal panel; Compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, and generates modulation data, and outputs a luminance compensation control signal according to the detection result of the highest and lowest gradation image data for each division area. Timing controller; And controlling the lighting (ON) or off (OFF) period of the light sources for each divided region of the backlight, and driving the bag by amplifying or attenuating the luminance of the corresponding divided regions according to the luminance compensation control signal for each divided region. It is characterized by having a light unit.

The timing controller compares the image data of the previous frame with the image data of the current frame for each of a plurality of preset division areas, and generates a modulation data according to a result of comparing the image data for each pixel of each division area. And a compensation control signal generator for detecting image data of the highest and lowest grayscales for each divided area and outputting the luminance compensation control signal for each of the divided areas according to the number of image data detected for the highest and lowest grayscale. It is characterized by.

The compensation control signal generation unit includes at least one counter to detect the number of image data of the highest and lowest grayscale for each divided area, and compares the number of detection of each of the highest and lowest grayscale image data with a preset reference number. The luminance compensation control signal for amplifying or attenuating the brightness of the backlight region corresponding to each divided region according to a result, or a ratio of the number of the highest and lowest grayscale image data detected to the number of image data for each divided region Characterized in that to generate and output.

The backlight unit is divided into a plurality of divided regions corresponding to a divided region of the liquid crystal panel, and a backlight in which a plurality of light sources generating light for each divided region are arranged; And controlling a lighting or extinguishing 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 according to the luminance compensation control signal. It characterized in that it comprises a backlight control unit for driving by amplifying or attenuating the brightness for each of the divided regions.

The backlight control unit is a driving power generation unit that supplies driving power to light sources for each divided area of the backlight, and light sources for the light sources for each divided area according to a duty ratio of the dimming control signal or a pulse width modulation signal. First to nth driving ICs that supply a driving signal and amplify or attenuate a current amount of at least one light source driving signal among the light source driving signals supplied to the light sources for each divided region according to the luminance compensation control signal. Characterized in that provided.

In addition, a method of driving a liquid crystal display according to an exemplary embodiment of the present invention for achieving the above object includes driving gates and data lines of a liquid crystal panel having a plurality of pixel regions to display an image; Compares the image data of the previous frame with the image data of the current frame for each of a plurality of preset division areas, and generates modulation data, and outputs a luminance compensation control signal according to the detection result of the highest and lowest gradation image data for each division area. To do; And controlling the lighting (ON) or off (OFF) period of the light sources for each divided region of the backlight, and amplifying or attenuating the luminance of the corresponding divided regions according to the luminance compensation control signal for each divided region and driving the driving. It is characterized by including.

In addition to generating the modulation data and outputting the luminance compensation control signal, image data of the previous frame and image data of the current frame are compared for each of a plurality of preset divided regions, and image data for each pixel of each divided region Generating the modulation data according to a comparison result, and detecting image data of the highest and lowest grayscales for each of the divided regions, and controlling the luminance compensation for each of the divided regions according to the number of image data detections of the highest and lowest grayscales And outputting a signal.

In the outputting of the luminance compensation control signal, detecting the number of the highest and lowest grayscale image data for each of the divided areas using at least one counter, and setting the preset number and the respective number of the highest and lowest grayscale image data The above-described method for amplifying or attenuating the brightness of a backlight area corresponding to each divided area according to a comparison result of a reference number or a ratio of the number of the highest and lowest grayscale image data detected to the number of image data for each divided area. And generating and outputting a luminance compensation control signal.

The driving of amplifying or attenuating the emission luminance of the divided regions may include disposing a plurality of light sources generating light for each of the divided regions corresponding to the divided regions of the liquid crystal panel; Controlling lighting or extinguishing periods 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 according to the luminance compensation control signal And a step of driving by amplifying or attenuating the brightness for each divided area.

The step of driving by amplifying or attenuating the emission luminance of the divided regions includes supplying driving power to light sources for each divided region of the backlight, and each division according to a duty ratio of the dimming control signal or a pulse width modulation signal. Supplying a light source driving signal to the light sources for each region, 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 each divided region according to the luminance compensation control signal to supply It is characterized by including the steps.

A liquid crystal display device and a driving method according to an embodiment of the present invention having the above characteristics improve the response speed of the liquid crystal to prevent deterioration of the image quality while compensating for backlight luminance in areas where the response speed of the liquid crystal cannot be improved. By doing so, the display quality of the image can be improved.

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

Hereinafter, a liquid crystal display device and a driving method 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 illustrating a liquid crystal display device according to an exemplary embodiment of the present invention.

The liquid crystal display device illustrated in FIG. 1 includes a liquid crystal panel 2 having a plurality of pixel areas to display an image; A data driver 4 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; Compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, generates modulation data (MData), and controls luminance compensation according to the detection results of the highest and lowest gradation image data for each division. A timing controller 8 for outputting the signal BU.BD; And controlling the lighting (ON)/off (OFF) period of the light sources for each divided region of the backlight 14, as well as controlling the emission luminance of the corresponding divided regions according to the luminance compensation control signal BU.BD for each divided region. And a backlight unit 12 driven by amplification or attenuation.

The liquid crystal panel 2 is 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 liquid crystal connected to a TFT. A capacitor Clc is provided. The liquid crystal capacitor Clc is composed of a pixel electrode connected to a 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 the scan pulses from each of the gate lines GL1 to GLn. The liquid crystal capacitor Clc implements gradation by charging the difference voltage between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusting the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage. The storage capacitor Cst is connected to the liquid crystal capacitor Clc in parallel 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 interposed between the insulating layer. Alternatively, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line interposed between the insulating layer.

The data driver 4 includes a data control signal (DCS) from the timing controller 8, for example, a source start pulse (SSP), a source shift clock (SSC), and a source output enable ( Modulated data (MData) aligned from the timing controller 8 is modulated with an analog voltage, that is, a video signal using a source output enable (SOE) signal. Specifically, the data driver 4 latches the image data VData input according to the SSC, and then, in response to the SOE signal, one horizontal line for each horizontal cycle in which a scan pulse is supplied to each gate line GL1 to GLn. The minute video signal is supplied to each data line DL1 to DLm. At this time, the data driver 4 selects a gamma voltage of a positive or negative polarity having a predetermined level according to the gradation value of the modulated data MData and supplies the selected gamma voltage to each data line DL1 to DLm as an image signal. do.

The gate driver 6 is a gate control signal (GCS) from the timing controller 8, for example, a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable ( The scan pulses are sequentially generated in response to the GOE (Gate Output Enable) signal, and are sequentially supplied 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. The gate-off voltage is supplied during a period in which 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 according to the GOE signal.

The timing controller 8 compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, and generates modulation data (MData) according to the comparison result of the image data. Then, the luminance compensation control signal BU.BD is output for each divided region according to the result of detecting the image data of the highest and lowest gradations for each divided region. Specifically, the timing controller 8 stores image data (RGB) input from an external graphic system, etc., in units of every frame, and compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset partition regions. . Then, after generating the modulation data (MData) so that the gradation value is modulated according to the comparison result of the image data for each pixel of each divided region, the data driver is arranged by arranging the modulation data (MData) to suit the driving of the liquid crystal panel 2. 4).

In addition, the timing controller 8 detects image data of the highest and lowest grayscales for each divided region and outputs a luminance compensation control signal BU.BD for each divided region according to the number of the image data detected for the highest and lowest grayscale. .

In addition, the timing controller 8 generates a gate control signal GCS and a data control signal DCS using external synchronization signals DCLK, DE, Hsync, and Vsync to generate a data driver 24 and a gate. The driver 26 is controlled. Then, a dimming control signal (Dim) or a pulse width modulation signal (PWM) is generated using at least one of the synchronization signals according to the brightness or luminance information of the aligned modulation data (MData), and the backlight unit ( The backlight unit 12 is also controlled by supplying it to 12). On the other hand, the dimming control signal (Dim) or pulse width modulated signal is generated separately from an external system such as a graphics card and is supplied to the backlight unit 12. Here, the dimming control signal Dim may be a digital signal for setting a duty ratio that is a driving current supply period (Dimming Time) ratio, or may be a pulse width modulation signal (PWM) with a duty ratio set.

The backlight unit 12 is divided into each of the divided areas of the backlight 14 according to a duty ratio of a dimming control signal (Dim) or a pulse width modulation signal (PWM) from an external system or timing controller 8 In addition to controlling the ON/OFF period of each light source, the luminance of the corresponding divided regions is amplified or attenuated according to the luminance compensation control signal BU.BD for each divided region and driven.

FIG. 2 is a block diagram of the timing controller illustrated in FIG. 1 in detail.

The timing controller 8 shown in FIG. 2 compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, and modulates the data (MData) according to the comparison result of image data for each pixel of each division area. ) High-speed driving circuit portion 21 for generating; A data alignment unit 22 for arranging and outputting the modulated data suitable for driving of the liquid crystal panel 2; Compensation control signal generator 23 that detects the highest and lowest grayscale image data for each divided area and outputs a luminance compensation control signal BU.BD for each divided area according to the number of the highest and lowest grayscale image data detected. ; 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 that generates a gate control signal GCS to control the driving timing of the gate driver 6.

The high-speed driving circuit unit 21 divides the image data of the previous frame and the image data of the current frame for each of a plurality of preset divided regions and compares the image data for each pixel of each divided region. In addition, modulation data (MData) are sequentially supplied to the data alignment unit 22 and the compensation control signal generation unit 23 according to the comparison result of the image data for each pixel. Accordingly, the data alignment unit 22 arranges the modulated data MData sequentially input according to the resolution and driving frequency of the liquid crystal panel 2 and supplies the data to the data driver 4.

The compensation control signal generating unit 23 detects image data of the highest and lowest grayscale for each divided region, and controls luminance compensation for each divided region according to the number or detection ratio of the image data of the highest and lowest grayscale for each divided region. The signal BU.BD is generated and output. Here, in the case of 8-bit image data, the image data of the highest and lowest gradations may be the lowest 0 gradation data and the highest 255 gradation data. In addition, in the case of 10-bit image data, the image data of the highest and lowest gradations may be the lowest 0 gradation data and the highest 1023 gradation data.

3 is a block diagram showing the high-speed driving circuit and the compensation control signal generator shown in FIG. 2 in detail.

The high-speed driving circuit 21 shown in FIG. 3 stores the image data RGB input from the outside in at least one frame unit and outputs the stored image data RGB as the previous data Fn-1 26 ), and a look-up table 27 that compares previous data Fn-1 from the frame memory 26 with the currently input image data Fn and selectively outputs the modulated data MData corresponding thereto. do. The high-speed driving circuit 21 configured as described above may be configured separately from the timing controller 8 to supply modulated data MData to the data alignment unit 22 of the timing controller 8. However, in the present invention, for convenience, an example in which the high-speed driving circuit 21 is built in the timing controller 8 will be described.

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

FIG. 4 is a table diagram illustrating a method of selecting and generating modulation data of the look-up table shown in FIG. 3.

Referring to FIG. 4, the look-up table 27 sequentially compares previous data Fn-1 sequentially supplied from the frame memory 26 with image data Fn, that is, current data Fn. do. Then, the modulation data (MData) corresponding to the compared result is selected and supplied to the data alignment unit 22. Here, the modulation data (MData) is data in which the gradation value of the current data (Fn) is modulated so that the liquid crystal can be driven at high speed. As shown in FIG. 4, when displaying 10-bit image data, using the look-up table 27 in which 10-bit modulated image data (MData) is stored, the highest and lowest gradation data of the image (0 gradations, 1023 gradations) cannot be compensated or tampered with. Accordingly, in the present invention, the highest and lowest gradation data (0 gradation, 1023 gradation) compensates for luminance using the brightness of the backlight.

5 is a diagram illustrating a division of a divided region showing an example of setting a divided region of the liquid crystal panel illustrated in FIG. 1.

The compensation control signal generation unit 23 includes at least one counter 28 to detect the number of image data of the highest and lowest grayscale for each divided area, and the number of detection of each of the image data of the highest and lowest grayscale and preset 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 grayscale image data compared to the number of image data for each divided region ( BU.BD).

The lowest and highest gradation image data detected by the compensation control signal generator 23 may be the lowest 0 gradation data and the highest 1023 gradation data in the case of 10-bit image data. Accordingly, the compensation control signal generation unit 23 detects the number of the lowest 0 gradation data and the highest 1023 gradation data for each divided area using the counter 28 provided therein. Then, when the maximum number of detected 1023 gradation data for each divided area is greater or more 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. In addition, when the number of detections of the lowest zero gradation data for each divided area is greater or more than a preset reference number, a compensation control signal BD for generating and outputting a brightness of the backlight area corresponding to the divided area is generated and output. do.

On the other hand, the compensation control signal generation unit 23 corresponds to the divided region when the ratio of the maximum number of detected 1023 gradation data to the total number of image data for each divided region is greater than or equal to a preset ratio (for example, 50%). A compensation control signal BU for amplifying the brightness of the backlight region may be generated and output. In addition, if the ratio of the number of detected minimum grayscale data to the total number of image data for each divided area is greater than or equal to a preset ratio (for example, 50%), the brightness of the backlight area corresponding to the divided area is attenuated. It is also possible to generate and output a compensation control signal (BD) for.

FIG. 6 is a block diagram showing the backlight unit of FIG. 1 in detail.

The backlight unit 12 of FIG. 6 is divided into a plurality of divided regions corresponding to a divided region of the liquid crystal panel, and a plurality of light sources (for example, LED arrays 38) generating light for each divided region are arranged. Back light 14; And LED arrays for each driving channel of the backlight 14 according to the duty ratio of the dimming control signal Dim or the pulse width modulation signal PWM supplied from the external system or the timing controller 8. In addition to controlling the OFF period, a backlight control unit 16 is provided to amplify or attenuate 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 lights each LED array according to a driving power supply Vled supplied to each of the LED arrays 38. (ON) to generate light. Each LED array 38 is divided and arranged for each divided area to correspond to the divided area of the liquid crystal panel. Each LED array of the backlight 14 is composed of only white LEDs to generate white light, and red, green, and blue LEDs are combined to generate white light.

The plurality of LED arrays generate light by the driving power supply (Vled), but the amount of light emission, such as the amount of LED driving current supplied to the driving channels of each output terminal and the LED driving signal (Ipwmn) of the driving current supply period (Dimming Time), that is, , The brightness level is controlled. Transistors Tr1 to Trm may be configured in driving channels of each output terminal. 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 each driving channel.

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

The backlight control unit 16 includes a driving power generation unit 32 that supplies driving power (Vled) to light sources for each divided area of the backlight 14, and a dimming control signal (Dim) or a pulse width modulation signal (PWM). Light source driving signals (Ipwm1 to Ipwmn) are supplied to the light sources for each divided area according to the duty ratio of ), and light sources supplied to the light sources for each divided area according to the luminance compensation control signals BU and BD And first to nth driving ICs 35 and 36 for amplifying or attenuating the current 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 power required to drive the first to n-th driving ICs 35 and 36 and generates IC power to supply the first to n-th driving ICs 35 and 36. Part 34; And a current control unit that amplifies or attenuates and supplies at least one feedback current among 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. (37) is further provided.

The driving power generating unit 32 generates a plurality of light sources provided in the backlight 14, that is, a driving power supply Vled suitable for driving the LED arrays 38, simultaneously or sequentially, thereby generating a plurality of LED arrays 38. Each is fed simultaneously or sequentially.

Each of the first to nth driving ICs 35 and 36 receives the pulse width modulation signal PWM directly from the external system or the timing controller 8, and when the dimming control signal Dim is input, the dimming control signal Dim ) To generate a pulse width modulated signal (PWM) to correspond to the duty ratio of. Accordingly, each of the first to nth driving ICs 35 and 36 adjusts the output timing of the LED driving signals Ipwm1 to Ipwmn of each LED array 38 according to the pulse width modulation signal PWM, and thus for each driving channel. The LED arrays are driven in a burst mode that turns on/off.

Further, each of the first to nth driving ICs 35 and 36 drives at least one of the light source driving signals Ipwm1 to Ipwmn supplied to the light sources for each divided region according to the luminance compensation control signals BU and BD It can be supplied by amplifying or attenuating the current amount of the signal.

Each of the first to nth driving ICs 35 and 36 is configured to adjust the brightness of the divided area so that the brightness of the divided area is amplified when the luminance compensation control signal BU is input to amplify the brightness of one of the divided areas. The amount of current of the light source driving signal IPwm is amplified and supplied. On the other hand, when the luminance compensation control signal BD is input to attenuate the brightness of one of the divided regions, the amount of light source driving signal IPwm of the corresponding divided region may be lowered and supplied so that the brightness of the divided region is attenuated.

The current controller 37 amplifies or attenuates feedback currents of at least one of 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. Order. As described above, when the feedback current fed back from the light sources of 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 and supplied to the divided region.

Accordingly, when the luminance compensation control signal BU is input to amplify the brightness of one of the divided regions, the current controller 37 feedbacks the feedback current Vf from the divided region so that the brightness of the divided region is amplified. ) Attenuated to supply. As described above, when the feedback current Vf of the corresponding divided region is attenuated according to 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, thereby increasing the brightness of the divided region. Can be increased. On the other hand, when a 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 divided region is amplified and supplied so that the brightness of the divided region is attenuated. . As described above, when amplifying the feedback current Vf of the corresponding divided region according to the luminance compensation control signal BU, the current amount of the light source driving signal IPwm is attenuated and supplied through the driving IC to the divided region, thereby increasing the brightness of the divided region. Can be lowered.

FIG. 7 is a diagram for explaining a method of controlling brightness of at least one divided region of the backlight shown in FIG. 6. And, Table 1 below sequentially shows the brightness control method of at least one divided region as shown in FIG. 7.

[Table 1]

Referring to Tables 1 and 7 above, each of the first to nth driving ICs 35 and 36 and the current controller 37 is supplied for each of the divided areas when the luminance compensation control signals BU and BD are input. The current amount of at least one light source driving signal among the light source driving signals Ipwm1 to Ipwmn may be supplied to be maintained or increased or decreased in units of a plurality of preset frame periods.

For example, when the luminance compensation control signal BU is input to amplify the brightness of any one of the divided areas, each of the first to nth driving ICs 35 and 36, the corresponding divided area for a period of 3 frames The current amount of the light source driving signal IPwm of the corresponding divided region can be amplified and supplied for a period of 3 frames so as to maintain the amplified state of. In contrast, when the luminance compensation control signal BU is input to amplify the brightness of one of the divided areas, each of the first to nth driving ICs 35 and 36 has one frame of brightness. The current amount of the light source driving signal IPwm of the corresponding divided region may be supplied so that it is amplified for a period and then reduced to a state before amplification over the remaining two frame periods.

Meanwhile, when the luminance compensation control signal BU is input to amplify the brightness of one of the divided regions, the current control unit 37 also corresponds to maintain the amplified state of the divided region for 3 frame periods. The feedback current Vf of the divided region can be attenuated and supplied to the driving IC. In addition, the feedback current Vf of the divided region may be attenuated and increased so that the brightness of the divided region is amplified for one frame period and then reduced to a state before being amplified over the remaining two frame periods.

FIG. 8 is another diagram for describing a method of controlling brightness of at least one divided region of the backlight illustrated in FIG. 6. And, Table 2 below sequentially shows the brightness control method of at least one divided region as shown in FIG. 8.

[Table 2]

Referring to Tables 2 and 8 above, each of the first to nth driving ICs 35 and 36 and the current controller 37 is supplied for each of the divided regions when the luminance compensation control signals BU and BD are input. The current amount of at least one light source driving signal among the light source driving signals Ipwm1 to Ipwmn may be supplied to be maintained or reduced in units of a plurality of preset frame periods.

For example, when the luminance compensation control signal BU is input to attenuate the brightness of any one of the divided regions, each of the first to nth driving ICs 35 and 36, the corresponding divided region for a period of 3 frames The current amount of the light source driving signal IPwm of the corresponding divided region may be attenuated for a period of 3 frames to maintain the attenuated state. In contrast, each of the first to nth driving ICs 35 and 36 is a light source driving signal of the corresponding divided region such that the brightness of the divided region is attenuated for one frame period and then increased to a state before being attenuated over the remaining two frame periods. (IPwm) can supply the amount of current.

Meanwhile, when the luminance compensation control signal BU is input to attenuate the brightness of one of the divided regions, the current controller 37 also applies to maintain the attenuated state of the divided region for 3 frame periods. The feedback current Vf of the divided region can be amplified and supplied to the driving IC. Then, the feedback current Vf of the divided region may be amplified and lowered again so that the brightness of the divided region is attenuated for one frame period and then increased to a state before being attenuated over the remaining two frame periods.

As described above, the liquid crystal display according to the exemplary embodiment of the present invention and a driving method thereof can improve a response speed of a liquid crystal by using a high-speed driving circuit to generate a modulated data to prevent image deterioration. In addition, it is possible to improve the display quality of an image by performing backlight luminance compensation in a region in which the response speed of the liquid crystal cannot be improved, that is, in a divided region in which image data having the lowest and highest gradations are distributed.

Through the above description, those skilled in the art will appreciate that various changes and modifications are possible without departing from the technical idea of the present 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 determined by the scope of the claims.

2: LCD panel 4: Data driver
6: Gate driver 8: Timing controller
12: back light unit 14: back light
16: Back light control unit 32: Driving power generation unit
34: IC power generating unit 35: first driving 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 driving data lines of the liquid crystal panel;
A gate driver driving gate lines of the liquid crystal panel;
Compares the image data of the previous frame with the image data of the current frame for each of a plurality of preset division areas, and generates modulation data, and outputs a luminance compensation control signal according to the detection result of the highest and lowest gradation image data for each division area. Timing controller; And
In addition to controlling the on (ON) or off (OFF) period of the light sources for each divided region of the backlight, the backlight is driven by amplifying or attenuating the luminance of the corresponding divided regions according to the luminance compensation control signal for each divided region Equipped with a unit,
The timing controller
A high-speed driving circuit unit that compares the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, and generates the modulation data according to a result of comparing the image data for each pixel of each division area, and
And a compensation control signal generator for detecting image data of the highest and lowest grayscales for each of the divided regions and outputting the luminance compensation control signal for each of the divided regions according to the number of image data of the highest and lowest grayscales. Liquid crystal display device. delete According to claim 1,
The compensation control signal generator
It is provided with at least one counter to detect the number of image data of the highest and lowest grayscale for each of the divided areas,
According to the comparison result of the number of detections of each of the highest and lowest grayscale image data and a preset reference number, or the ratio of the number of the highest and lowest grayscale image data to the number of the image data for each divided region, the respective divided regions And generating and outputting the luminance compensation control signal for amplifying or attenuating the brightness of a corresponding backlight region. The method of claim 3,
The backlight unit
A backlight divided into a plurality of divided regions corresponding to the divided regions of the liquid crystal panel and having a plurality of light sources for generating light for each divided region; And
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, the lighting or turning-off period of the light sources for each driving channel of the backlight is controlled, and the luminance compensation control signal A liquid crystal display device comprising a backlight control unit for driving by amplifying or attenuating brightness for each divided area. The method of claim 4,
The backlight control unit
A driving power generation unit supplying driving power to the light sources for each divided area of the backlight, and supplying a light source driving signal to the light sources for each divided area according to the duty ratio of the dimming control signal or the pulse width modulation signal, together,
And first to nth driving ICs that amplify or attenuate a current amount of at least one light source driving signal among the light source driving signals supplied to the light sources for each divided region according to the luminance compensation control signal. Liquid crystal display. Driving gates and data lines of a liquid crystal panel having a plurality of pixel regions to display an image;
Compares the image data of the previous frame with the image data of the current frame for each of a plurality of preset division areas, and generates modulation data, and outputs a luminance compensation control signal according to the detection result of the highest and lowest gradation image data for each division area. To do; And
In addition to controlling the lighting (ON) or off (OFF) period of the light source for each divided region of the backlight, a step of driving by amplifying or attenuating the luminance of the corresponding divided regions according to the luminance compensation control signal for each divided region Including,
In addition to generating the modulation data and outputting the luminance compensation control signal is
Comparing the image data of the previous frame and the image data of the current frame for each of a plurality of preset division areas, and generating the modulation data according to a result of comparing the image data for each pixel of each division area; and
And detecting image data of the highest and lowest grayscales for each of the divided regions, and outputting the luminance compensation control signal for each of the divided regions according to the number of image data detections of the highest and lowest grayscales. How the device is driven. delete The method of claim 6,
The luminance compensation control signal output step is
Detecting the number of the highest and lowest grayscale image data for each of the divided areas using at least one counter, and
According to the comparison result of the number of detections of each of the highest and lowest grayscale image data and a preset reference number, or the ratio of the number of the highest and lowest grayscale image data to the number of the image data for each divided region, the respective divided regions And generating and outputting the luminance compensation control signal for amplifying or attenuating the brightness of a corresponding backlight region. The method of claim 8,
Driving by amplifying or attenuating the luminance of the divided regions
Disposing a plurality of light sources for generating light for each of the divided regions corresponding to the divided regions of the liquid crystal panel;
Controlling a lighting or extinguishing 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 a timing controller, and
And amplifying or attenuating brightness for each of the divided regions according to the luminance compensation control signal, and driving the liquid crystal display device. The method of claim 9,
Driving by amplifying or attenuating the luminance of the divided regions
Supplying driving power to light sources for each of the divided regions of the backlight;
Supplying a light source driving signal to the light sources for each of the divided regions according to the duty ratio of the dimming control signal or the pulse width modulation signal, and
And amplifying or attenuating and supplying a current amount of at least one light source driving signal among the light source driving signals supplied to the light sources for each divided region according to the luminance compensation control signal.

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