KR101415062B1 - Liquid crystal display device and drivign method thereof - Google Patents

Abstract

According to the present invention, in order to simultaneously improve motion blur and brightness in a moving image in a panel capable of high-speed driving relative to an input frame frequency, luminance analysis of R, G, and B data is performed on a frame or pixel basis, And a BDI (or a MEDI and a scanning backlight method) to implement an image. The liquid crystal display according to the first exemplary embodiment of the present invention includes R, G, and B data The histogram is analyzed in units of frame or pixel and the intermediate data generated by selecting either BDI or MEDI according to the luminance characteristic is inserted into the original data to output the image data And a luminance improving unit; A timing controller for generating correction data by rearranging the R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the corrected data information from the timing controller; A gate driver for generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel receiving the pixel data from the data driver and implementing an image.

Motion Blur, MEDI, BDI, Brightness Improvement

Description

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

The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device and a driving method thereof, A liquid crystal display device which implements an image by selecting one of the methods of the brightness-enhanced image insertion (MEDI) and the black data insertion (BDI) (or the MEDI and the scanning backlight) according to the brightness characteristic thereof, And relates to a driving method thereof.

 In the 21st century information society, various flat panel display devices which can reduce weight and volume, which is a disadvantage of cathode ray tube (CRT) tube, have appeared. Currently, flat panel display devices include a liquid crystal display, a field emission display, a plasma display panel, and a light emitting display.

Among them, the liquid crystal display device can be downsized as compared with the cathode ray tube, and the use range of the liquid crystal display device is extended to desktop computers, notebook computers, office automation devices such as copying machines, and mobile phones.

However, such a liquid crystal display device exhibits a motion blur phenomenon in which an image is displayed blurred due to the signal voltage holding characteristic of a liquid crystal.

In this regard, the data characteristics of a CRT (Cathode Ray Tube) and a liquid crystal display device will be described with reference to FIGS. 1 to 7.

As shown in FIG. 1, the CRT emits phosphors only for a very short initial period of one field period to display data, and an impulse type in which almost all of a field period remains in a pause interval, . Accordingly, as shown in FIG. 2, the perceived image of the moving picture perceived by the spectator in the CRT is clearly displayed.

In contrast, as shown in FIG. 3, during the scanning period in which the scan high voltage (Vgh) is supplied, the liquid crystal display supplies data to the liquid crystal and data supplied to the liquid crystal in the non-scanning period, do. Accordingly, in the liquid crystal display device as shown in Fig. 4, the display image appears blurred due to the motion blurring phenomenon.

The difference of these perceptual images is caused by the integration effect of the images which are temporally continuous in the eye following the motion. Therefore, even if the response speed of the liquid crystal display device is high, the viewer will see a blurry image due to a discrepancy between the motion of the eyes and the static image of each frame.

In order to alleviate motion blurring of such a conventional liquid crystal display device, a method of reducing holding time and inserting black data during a frame period has been proposed.

As shown in FIG. 6, the black data insertion method differs from the general method in which one frame data is supplied during one frame (1 frame) period as shown in FIG. 5, and the holding time (D1 to D5) And the black data B1 to B5 are inserted to drive the liquid crystal display device in a similar impulse type to alleviate the motion blurring phenomenon.

However, although the motion blurring problem can be solved to some extent by such a black data insertion method, the data holding time of each frame is reduced and the black data is inserted. As a result, as shown in FIG. 7, There is a problem that the temperature is significantly lowered by 30% or more.

Meanwhile, a method of generating new frame data as intermediate data by using a motion vector has been proposed in order to solve the problem of luminance degradation.

In other words, such a MEDI scheme extracts motion vectors of incoming images successively, predicts the intermediate image through it, generates a virtual image (or intermediate data), inserts it between the existing frame data and frame data, and outputs do.

However, since MEDI can not be fully implemented for all images, artifacts arise due to errors in the algorithm when generating intermediate data.

SUMMARY OF THE INVENTION The present invention is conceived to solve the problems as described above, and its object is to provide a black data generating unit (or a scanning backlight unit for scanning and driving a backlight) for generating and inserting black data, (Or scanning backlight driving) and intermediate data generation by motion vectors according to the brightness characteristics of the image data, and to implement the image A liquid crystal display device and a driving method thereof.

According to an aspect of the present invention, there is provided a liquid crystal display (LCD) device for receiving R, G, and B data from outside and analyzing a histogram in units of a frame or a pixel, An image quality and brightness enhancement unit for outputting data by inserting intermediate data generated by selecting one of BDI and MEDI according to luminance characteristics into original data; A timing controller for generating correction data by rearranging the R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the corrected data information from the timing controller; A gate driver for generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel in which pixel data is received from the data driver and an image is implemented.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display, comprising: analyzing a histogram by receiving R, G, and B data of a frame or pixel unit from the outside; Calculating a representative value of a tone value obtained by analyzing the histogram; Comparing the calculated representative value with a reference value of the maximum gradation luminance; Outputting black data to the original data when the representative value is equal to or less than the reference value and outputting the black data by doubling the luminance of the original data; And generating intermediate data based on the motion vectors of the original data and the previous data when the representative value is equal to or greater than the reference value as a result of the comparison, inserting the intermediate data into the original data and outputting the generated intermediate data.

The liquid crystal display according to the second embodiment of the present invention receives the R, G, and B data from the outside and analyzes the histogram in units of frames or pixels, and determines whether any one of the scanning backlight or MEDI The image quality and brightness enhancement unit for driving the backlight by scanning or generating intermediate data, inserting the intermediate data into the original data, and outputting the inserted data; A timing controller for generating correction data by rearranging the R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the corrected data information from the timing controller; A gate driver for generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel receiving the pixel data from the data driver and implementing an image.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display, including the steps of: analyzing a histogram by receiving R, G, and B data of a frame or pixel unit from the outside; Calculating a representative value of a tone value obtained by analyzing the histogram; Comparing the calculated representative value with a reference value smaller than a maximum gradation luminance; Scanning the backlight when the representative value is equal to or less than a reference value; And generating intermediate data based on the motion vectors of the original data and the previous data when the representative value is equal to or greater than the reference value as a result of the comparison, inserting the intermediate data into the original data and outputting the generated intermediate data.

As a result of the above configuration, the liquid crystal display according to the present invention analyzes histograms of R, G, and B data input from the outside in units of frames or pixels, and then, based on the comparison between the analyzed values and an initial reference value, Or scanning backlight) and the MEDI method, thereby enabling the image processing to be performed at a high speed relative to the input frame frequency, thereby improving luminance and motion blur at the time of implementing a moving image, thereby improving the image quality.

Hereinafter, the configuration and the driving method will be described in more detail with reference to the drawings.

8 is a block diagram illustrating an entire driving unit of the liquid crystal display according to the first embodiment of the present invention.

8, the liquid crystal display according to the first exemplary embodiment of the present invention receives R, G, and B data from outside and analyzes histograms in units of frames or pixels, and according to the luminance characteristics, An image quality and brightness enhancement unit for inserting intermediate data generated by selecting one of the methods of MEDI and MEDI into original data and outputting the data; A timing controller for generating correction data by rearranging the R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the corrected data information from the timing controller; A gate driver for generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel receiving the pixel data from the data driver and implementing an image.

First, the liquid crystal panel 120 is provided with a plurality of data lines DL1 to DLm which are insulated from each other by a plurality of gate lines GL1 to GLn and their gate lines GL1 to GLn, GL1 to GLn and the data lines DL1 to DLm are defined in a matrix. At this time, each liquid crystal cell has a thin film transistor connected to any one of n gate lines GL1 to GLn and to m data lines DL1 to DLm.

On the other hand, the backlight 135 is composed of a plurality of lamps such as CCFL (Cold Cathode Fluorescent Lamp) or EEFL (External Electrode Fluorescent Lamp) which are turned on by AC high voltage, And then sent to the liquid crystal panel 120 positioned.

The lamp driver 133 receives a DC voltage of approximately 24 V from the power supply voltage generator 130, converts the DC voltage into a DC AC waveform, converts the AC waveform to a high AC AC voltage, and applies the AC voltage to the backlight 135.

The power supply voltage generation unit 130 includes an AC-DC rectification unit that receives a commercial voltage from an external source and generates a DC voltage of about 12 V, a DC-DC converter (DC-DC converter) that generates various kinds of DC voltages using the DC voltage, DC converter. Here, the DC-DC converter is formed by being integrated in a PWM IC (Pulse Width Modulation Integrated Circuit) and coupled to peripheral circuits surrounding the PWM IC to supply the common voltage Vcom, the power supply voltage Vdd, Off voltage (Vgl, Vgh), and the like.

The reference voltage generating unit 131 divides the power supply voltage Vdd provided from the power supply voltage generating unit 130 to generate gamma reference voltages Vref at various levels and supplies the gamma reference voltages Vref to the data driver 116 to the gamma gradation voltage circuit (not shown). At this time, a plurality of gamma reference voltages Vref having various levels are generated through a plurality of resistors connected in series.

The MEDI / BDI judging unit 210 includes a MEDI / BDI judging unit 210 and an intermediate data generating unit 220. The MEDI / BDI judging unit 210 judges whether the R, G, B data is first analyzed by a histogram in units of frames (or pixels) to calculate a representative value, and the representative value is compared with an initially set reference value of the liquid crystal display device to determine (or select) an image implementation method of either MEDI or BDI The intermediate data generating unit 220 outputs data generated by inserting black data as intermediate data into original data through the BDI unit according to the selected result, or outputs the generated current data to the original data through the MEDI unit And the previous frame data, and inserts the intermediate data for each frame (or pixel) through the motion vector to output the generated data.

The timing controller 111 includes a data rearrangement unit for supplying the data driver 120 with the correction data Do DATA rearranging the R, G, and B data frequency-demultiplexed from the image quality and luminance improvement unit 200, Horizontal and vertical synchronizing signals Vsync and Hsync from an interface 100 interfacing with an external system (or device) and receiving R, G, B And a control signal generator for generating a gate control signal for controlling the gate driver 115 and a data control signal for the data driver 116 so as to be synchronized with the data. At this time, the timing controller 111 rearranges the R, G, and B data so as to correspond to the gradation information by using the logic voltage Vlog generated from the power supply voltage generation unit 130.

The timing controller 111 first controls a gate shift clock GSC, a gate output enable GOE and a gate start pulse as gate control signals for controlling the gate driver 115, GSC is a signal for determining the time when the gate of the thin film transistor is on / off (On / Off), GOE is a signal for controlling the output of the gate driver 115, and GSP is a vertical It is a signal that informs the first driving line of the screen among the synchronizing signals.

The timing controller 111 also controls the data driver 116 as a data control signal that controls a source sampling clock (SSC), a source output enable (SOE), a source start pulse SSP), liquid crystal polarity reverse (POL), data polarity selection (REV), odd / even pixel data (Odd / Even data)

Here, the SSC is used as a sampling clock for latching data in the data driver 116, and determines the driving frequency of the data drive IC. The SOE allows the data latched by the SSC to be transmitted to the liquid crystal panel 120. The SSP is a signal for notifying the start of data latching or sampling during one horizontal synchronization period. POL is a polarity signal to drive the liquid crystal in positive and negative polarity for driving the liquid crystal inversion. REV is a signal for selecting the polarity of data to be transmitted, and the odd / even pixel data is the odd data of the odd pixel and the even data of the even pixel.

The gate driver 115 receives the gate voltages Vgl and Vgh generated by the power supply voltage generation unit 130 and sequentially outputs the gate voltages Vgl and Vgh to the gate lines GL1 to GLn in accordance with the control signal of the timing controller 111. [ , Vgh) to drive thin film transistors connected to the gate lines GL1 to GLn.

The data driver 116 converts the R, G, and B data output from the timing controller 111 into pixel voltages as analog signals and supplies the pixel voltages to the gate lines GL1 through GLn during one horizontal period And supplies the pixel voltages of one horizontal line to the data lines DL1 to DLm. At this time, the data driver 116 converts R, G, and B data into pixel voltages using a gamma voltage supplied from a gamma voltmeter (not shown) and outputs the converted pixel voltages.

More specifically, the data driver 116 includes a data register in which data (RGB) output from the timing controller 111 is input, a shift register for generating a sampling clock, a shift register for shifting the shift register and m data lines A first latch and a second latch connected between the first and second latches DL1 to DLm and a gamma gradation voltage circuit for dividing the gamma reference voltages Vref and supplying the divided voltages to a digital to analog converter DAC, Analog converter and an output section.

Here, the data register temporarily stores the data (RGB) from the timing controller 111 and then supplies the stored data (RGB) to the first latch.

The shift register shifts the source start pulse SSP from the timing controller 111 according to the source sampling clock SSC to generate a sampling signal. In addition, the shift register shifts the source start pulse SSP and transfers the carry signal CAR to the next-stage shift register.

The first latch samples the digital video data RGB from the data register in response to the sampling signal sequentially input from the shift register, and latches the digital video data RGB one line at a time.

The second latch latches the digital data RGB input from the first latch and then outputs the latched digital video data RGB in response to the SOE signal from the timing controller 130 so that data can be simultaneously output.

The gamma gradation voltage circuit divides gamma reference voltages Vref generated at the various levels generated by the reference voltage generator 131 to generate gamma gradation voltages corresponding to the respective gradations such as 256 gradations (or 64 gradations).

The DAC causes the gradation voltage of the corresponding level supplied from the gamma gradation voltage circuit to be selected and output corresponding to the video data (RGB) from the second latch. Of course, the gradation voltage here is selected and output as either a positive polarity (+) or a negative polarity (-) according to the polarity control signal POL from the timing controller 111.

The output circuit temporarily stores the R, G, and B pixel voltages of the analog form selected and output from the DAC in an internal buffer, and outputs the R, G, and B pixel voltages to the liquid crystal panel 120.

Through the above process, the thin film transistor on the liquid crystal panel 120 outputs the pixel voltage (or gradation voltage) from the data lines DL1 to DLm in response to the gate voltages Vgl and Vgh from the gate lines GL1 to GLn And the liquid crystal cell controls the transmittance of the light provided from the backlight 135 by driving the liquid crystal located between the common electrode and the pixel electrode in response to the pixel voltage. The image is realized by the transmittance of transmitted light.

9 is a sub-block diagram illustrating the image quality and brightness enhancement unit of FIG.

9, the image quality and brightness improver 200 according to the present invention receives the R, G, and B data from the outside as described above, analyzes the histogram, compares the representative value of the histogram with the set reference value A MEDI / BDI determination unit 210 for determining an intermediate data generation method according to the comparison result, and an MEDI / BDI determination unit 210 according to a result of the MEDI / BDI determination unit 210, And an intermediate data generating unit 220 for outputting the data inserted into the data.

Here, the MEDI / BDI determination unit 210 includes a histogram analysis unit 211 that generates a histogram by arranging luminance components corresponding to gradations through luminance analysis on a frame-by-frame basis, and a representative value of the histogram, A representative value calculating unit 213 for calculating any one value corresponding to the intermediate value, the mode value, the maximum value, the minimum value, and the like; Mode, when 255 gradations of 256 gradations correspond to full-white, the reference gradation is compared with a reference value corresponding to 1/2, 1/3, etc. of the maximum gradation luminance corresponding to the full white, And a selection unit 217 for designating one path in accordance with the control signal output from the comparison unit 215. [

When the representative value from the MEDI / BDI determination unit 210 becomes equal to or less than the initial reference value, the intermediate data generation unit 220 determines that the frame is black, inserts black data into the original data and outputs the same, A BDI unit 223 for doubling the luminance of the data and outputting the data when the representative value from the MEDI / BDI determination unit 210 is equal to or larger than the reference value that is initially set, And a MEDI unit 221 for generating intermediate data by the motion vector, inserting it into the original data, and outputting the original data while maintaining the luminance of the original data.

FIG. 10 is a diagram showing a data processing state when the BDI section is selected in the MEDI / BDI determination section and the intermediate data generation section in FIG. 9, and FIG. 11 is a diagram illustrating a data processing state in the MEDI / BDI determination section and the intermediate data generation section, And shows the data processing state when it is selected.

First, referring to FIG. 10 with reference to FIG. 9, it is assumed that the BDI unit 223 is selected in the intermediate data generation unit 220.

For example, as shown in FIG. 10 (a), data corresponding to 60 frames (60 Hz) per second will be input from the outside to the MEDI / BDI determination unit 210.

At this time, the histogram analyzer 211 analyzes the luminance components of the data for each unit frame input for 1/60 second [sec] and then examines the distribution of the tone values corresponding to the luminance components.

As a result, when the gray level value of the frame data corresponds to the 255 level among the 256 gray levels in the normally black mode as shown in FIG. 10 (b), it is mostly distributed in the low gray level when the gray level is full white.

Then, the representative value calculating unit 213 calculates a representative value of the histogram analyzed by the histogram analyzing unit 211. In other words, the representative value calculating unit 213 generates a representative histogram in the plurality of histograms analyzed by the histogram analyzing unit 211. [

Then, the comparator 215 compares the representative value with a preset reference value, which is smaller than the maximum gradation luminance as mentioned above, and then when the representative value becomes equal to or greater than the reference value X (Or the representative value becomes larger than the reference value X), it is determined that the unit frame is almost white and the corresponding control signal is provided to the selection unit 217. For example, the comparison unit 215 may generate and send a control signal of "00" to drive the BDI unit 223.

Then, the selection unit 217 opens a channel for selecting the BDI 223 according to the above control signal. Of course, such a selector 217 may be constituted by a switching circuit or a multiplexer which is turned on / off according to a control signal.

10 (c), the BDI unit 223 performs the R, G, and B correction data supplied from the timing controller through the selection unit 217 in the order of 1/120 second [sec] The correction data of R, G, and B of the unit, that is, the original data is output, and black data is output as intermediate data for 1/120 second [sec].

At this time, since the luminance of the original data is reduced to 1/2 due to the influence of the black data, the gray level value for the original data is reset (or gamma corrected) to compensate for the luminance by doubling the luminance.

As a result, according to the present invention, since the histogram is analyzed for each unit frame and the black data is partially inserted as the intermediate data only when it is selected by the luminance characteristic, black data is inserted for all the frames, It is possible to improve the luminance.

Now, referring to FIG. 11 with reference to FIG. 9, consider the case where the MEDI unit 221 is selected in the intermediate data generation unit 220. FIG.

For example, data corresponding to 60 frames (60 Hz) per second is input from the outside to the MEDI / BDI determination unit 210 as shown in FIG. 11 (a).

At this time, the histogram analyzer 211 analyzes the luminance components of the data for each unit frame for 1/60 second [sec], and then examines the distribution of the tone values corresponding to the luminance components.

As a result, when the gray level of the frame data corresponds to the 255 level among the 256 gray levels in the normally black mode as shown in FIG. 11B, most of the gray level values are distributed in the high gray level.

Then, the representative value calculating unit 213 calculates the representative value of the histogram analyzed by the histogram analyzing unit 211. [ In other words, the representative value calculation unit 213 generates a representative histogram in the plurality of histograms analyzed by the histogram analysis unit 211. [

The comparator 215 compares the representative value with a preset reference value X and a reference value X smaller than the maximum gradation luminance as mentioned above. (Or the representative value becomes larger than the reference value X), it is determined that the unit frame is almost white and a control signal is provided to the selection unit 217. [ For example, the comparison unit 215 may generate and provide a control signal of "11" to drive the MEDI unit 221. [

Then, the selection unit 217 opens the path for selecting the MEDI 221 according to the above control signal. The selector 217 may be a switching circuit or a multiplexer that is turned on / off according to a control signal.

11 (c), the MEDI unit 221 uses the correction data of R, G, and B supplied from the timing controller through the selection unit 217 as correction data, And outputs the correction data of R, G and B, that is, the original data. Then, the motion vector is extracted as the intermediate data for 1/120 second through the previous data stored in the frame memory separate from the current original data. The intermediate data is generated using the motion vector, inserted into the original data, and the intermediate data is output. As a matter of course, a method of generating and inserting the same data as the original data in the original data by data doubling as the intermediate data, and outputting it may be possible.

In both cases, the original data is not influenced by the luminance due to the intermediate data, so the data is outputted while maintaining the luminance of the original data.

As a result, since the present invention generates intermediate data by the MEDI method only when it is partially selected by the luminance characteristic of each unit frame, it is possible to implement all the frame data only in the MEDI method, It is possible to reduce the number of errors occurring during the operation.

However, if the brightness characteristic is analyzed for each unit frame as described above and the image is implemented by selecting one of the MEDI and the BDI according to the result, the image processing may take some time, The contrast ratio for a specific object of the time image may be somewhat reduced.

In the present invention, a histogram is analyzed for each pixel unit of R, G, and B, not shown in a separate drawing, and a representative value is calculated from the grayscale value of a pixel distributed in the histogram, Depending on the outcome, the method of selecting one of the MEDI or BDI methods can not be ruled out.

In such a case, compared with the above-mentioned frame-by-frame processing method, it is not significantly different from the system, but the image processing speed is likely to be increased. However, even in such a pixel-based image processing method, the motion blur improvement effect on a specific object of an image may be somewhat reduced when a moving image is implemented.

Except for this point, the data processing method of the pixel unit is not much different from the processing method of each frame, so other detailed contents are superseded.

FIG. 12 is a block diagram of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 13 is a sub-block diagram illustrating the image quality and brightness improver of FIG.

12 and 13, the liquid crystal display according to the second embodiment of the present invention receives the R, G, and B data from the outside and analyzes the histogram in frames or pixel units, An image quality and brightness enhancement unit that selects either the scanning backlight or the MEDI to scan or drive the backlight or inserts intermediate data into the original data and outputs the result; A timing controller for generating correction data by rearranging the R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the corrected data information from the timing controller; A gate driver for generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel receiving the pixel data from the data driver and implementing an image.

First, the liquid crystal panel 320 includes a plurality of data lines DL1 to DLm that are insulated from each other by a plurality of gate lines GL1 to GLn and their gate lines GL1 to GLn, GL1 to GLn and the data lines DL1 to DLm are defined in a matrix. At this time, each liquid crystal cell has a thin film transistor connected to any one of n gate lines GL1 to GLn and to m data lines DL1 to DLm.

On the other hand, the backlight 335 is composed of a plurality of lamps such as a CCFL or an EEFL which are turned on by an AC high voltage, and the plurality of lamps are divided into at least two groups or regions to be driven. At this time, the lamps are partially driven to provide light by being synchronized with the time when the image is implemented on the liquid crystal panel 320 located on the front side.

The lamp driving unit 333 receives a DC voltage of about 24V from the power supply voltage generating unit 330, converts the DC voltage into a DC AC waveform, converts the AC waveform into a high AC AC voltage and applies it to the backlight 335, The control signal is received from the timing controller 311, and the backlight is dividedly driven.

The power supply voltage generating unit 330 includes an AC-DC rectifying unit for receiving a commercial voltage from the outside to generate a voltage of about 12V DC, and a DC-DC converter for generating various kinds of DC voltages using the DC voltage . Here, the DC-DC converter is formed by being integrated in the PWM IC, and the common voltage Vcom, the power supply voltage Vdd, and the gate on / off voltages Vgl and Vgh through the coupling with the peripheral circuits surrounding the PWM IC, And so on.

The reference voltage generator 331 divides the power supply voltage Vdd supplied from the power supply voltage generator 330 to generate gamma reference voltages Vref at various levels and supplies the gamma reference voltages Vref to the data driver To the gamma gradation voltage circuit (not shown). At this time, a plurality of gamma reference voltages Vref having various levels are generated through a plurality of resistors connected in series.

The image quality and brightness enhancement unit 400 is divided into a scanning backlight / MEDI determination unit 410 and a scanning backlight / intermediate data processing unit 420. In the scanning backlight / MEDI determination unit 410, , G and B data are first analyzed by a histogram in units of frames (or pixels), a representative value is calculated, and the representative value is compared with an initially set reference value of the liquid crystal display device to determine a method of implementing one of scanning backlight driving and MEDI And the scanning backlight / intermediate data processing unit 420 controls the lamp driving unit 333 through the scanning backlight unit according to the selected result so that the backlight is dividedly driven. Alternatively, the backlight is dividedly driven through the MEDI unit, Extracts a motion vector between data and inserts intermediate data for each frame (or pixel) through the motion vector to generate a motion vector Data is output.

The timing controller 311 includes a data rearrangement unit for rearranging the R, G, and B data frequency-demultiplexed from the image quality and brightness enhancement unit 400 and supplying the data to the data driver 316 again, Horizontal synchronizing signals Vsync and Hsync from the interface 300 which is coupled to the gate driver (not shown) to be synchronized with the R, G, and B data frequency-demultiplexed from the image quality and brightness improving unit 400 315, and a control signal generator for generating a data control signal for the data driver 316, and the like. At this time, the timing controller 311 rearranges the R, G, and B data so as to correspond to the gradation information using the logic voltage Vlog generated and supplied from the power supply voltage generating unit 330.

The timing controller 311 first generates a gate shift clock GSC, a gate output enable GOE and a gate start pulse GSP as gate control signals for controlling the gate driver 315, GOE is a signal for controlling the output of the gate driver 315, and GSP is a signal for notifying the first drive line of the screen from one vertical synchronization signal.

The timing controller 311 also supplies a source control signal SSC, a source output enable SOE, a source start pulse SSP, a liquid crystal polarity reversal POL, a data polarity Selection (REV), odd / even pixel data signals, and the like.

The gate driver 315 receives the gate voltages Vgl and Vgh generated by the power supply voltage generator 330 and sequentially outputs the gate voltages Vgl and Vgh to the gate lines GL1 to GLn in accordance with the control signal of the timing controller 311. [ , Vgh) to drive thin film transistors connected to the gate lines GL1 to GLn.

The data driver 316 converts the corrected R, G, and B data (DoDAT) output from the timing controller 311 into pixel voltages that are analog signals and supplies a gate voltage to each of the gate lines GL1 to GLn And supplies the pixel lines of one horizontal line to the data lines DL1 to DLm during one horizontal period to be supplied. At this time, the data driver 316 converts R, G, and B data into pixel voltages using a gamma voltage supplied from a gamma voltmeter (not shown) and outputs the converted pixel voltages.

Through the above process, the thin film transistors on the liquid crystal panel 320 emit pixel voltages (or gradation voltages) from the data lines DL1 to DLm in response to the gate voltages Vgl and Vgh from the gate lines GL1 to GLn And the liquid crystal cell controls the transmittance of light provided from the backlight 335 by driving the liquid crystal positioned between the common electrode and the pixel electrode in response to the pixel voltage. The image is realized by the transmittance of transmitted light.

13 is a sub-block diagram illustrating the image quality and brightness enhancement unit of FIG.

As shown in FIG. 13, the image quality and brightness improver 400 according to the present invention receives R, G, and B data from outside and analyzes the histogram. Then, the representative value from the histogram is compared with the set reference value, A scanning backlight / MEDI determination unit 410 for controlling the lamp driving unit to drive the backlight according to a result of the scanning to drive the backlight or determining the generation of intermediate data according to a motion vector, and a scanning backlight / MEDI determination unit 410. The scanning backlight / And a scanning backlight / intermediate data processing unit 420 for generating intermediate data by selecting one of the scanning backlighting methods or for driving the backlight scanning operation.

Here, the scanning backlight / MEDI determination unit 410 includes a histogram analysis unit 411 for generating a histogram by arranging luminance components corresponding to gradations through luminance analysis on a frame-by-frame basis, and a representative value of the histogram, A representative value calculating unit 413 for calculating any one value corresponding to a deviation, an intermediate value, a mode value, a maximum value, a minimum value, and the like, and a reference value smaller than the maximum gradation luminance, If the gradation of the 255 level in the gradation corresponds to full-white, the comparator compares the reference value with the reference value corresponding to 1/2, 1/3, etc. of the gradation luminance corresponding to the full white and outputs a control signal in accordance with the comparison result And a selection unit 417 for designating one path according to the control signal output from the comparison unit 415.

The scanning backlight / intermediate data processing unit 420 includes a scanning backlight unit 423 for controlling the lamp driving unit to scan and drive the backlight when the representative value from the scanning backlight / MEDI determination unit 410 is equal to or lower than an initially set reference value, When the representative value from the backlight / MEDI determination unit 410 is equal to or larger than the initially set reference value, the frame data is determined to be white and the motion vector is extracted from the previous frame data (or previous frame data) stored in another memory. And an MEDI unit 421 for generating intermediate data by a vector, inserting the intermediate data into the original data, and outputting the original data while maintaining the luminance of the original data.

Of course, the scanning backlight technology here employs a method of implementing the impulse driving by dividing the backlight installed on the back surface of the liquid crystal panel into a plurality of regions and driving them, and by turning on / off the lamps in the respective regions in accordance with control signals from the outside .

However, according to the present invention, as a scanning backlight technique, black data is inserted between existing frame data and frame data, for example, as in the BDI method, and the lamps of the respective regions, which are divided and driven at the back of the liquid crystal panel, And the like. For example, when black data is implemented, the lamp is temporarily turned off to drive the backlight.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

2 is a view showing a perception image with a cathode ray felt by a spectator;

3 is a view showing the luminescence characteristics of the liquid crystal display device

4 is a view showing a perception image of a liquid crystal display device felt by a spectator

5 is a diagram showing a data alignment state in the normal state

6 is a diagram showing a data alignment state in which black data is inserted in all gray scale regions

FIG. 7 is a graph showing a comparison between the luminance in the normal state and the luminance in the black data insertion

8 is a block diagram of a liquid crystal display device according to the first embodiment of the present invention

9 is a sub-block diagram showing the picture quality and brightness enhancement unit of FIG.

FIG. 10 is a diagram showing a data processing state when the BDI section is selected in the MEDI / BDI determination section and the intermediate data generation section in FIG. 9; FIG.

11 is a diagram showing a data processing state when the MEDI section is selected in the MEDI / BDI determination section and the intermediate data generation section in Fig. 9

12 is a block diagram of a liquid crystal display device according to a second embodiment of the present invention

13 is a sub-block diagram showing the picture quality and brightness enhancement unit of Fig.

Claims (12)

The histogram is analyzed on a frame or pixel basis by receiving R, G, and B data from the outside, and intermediate data generated by selecting one of BDI and MEDI according to the luminance characteristic is converted into original data And outputs the data; A timing controller for generating correction data by rearranging R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the correction data from the timing controller; A gate driver for generating and outputting a gate on / off voltage in accordance with the control signal from the timing controller; And a liquid crystal panel that receives image data from the data driver and implements an image. The apparatus of claim 1, wherein the image quality and brightness enhancement unit receives the R, G, and B data from the outside, analyzes the histogram, compares the R, G, and B data with a reference value, and determines a method of generating intermediate data according to the comparison result. And an intermediate data generation unit for generating intermediate data by either the MEDI or BDI method according to the result of the MEDI / BDI determination unit. 3. The apparatus of claim 2, wherein the MEDI / BDI determination unit comprises: a histogram analyzing unit for analyzing the histogram by using the R, G, and B data applied from the outside as a frame or a pixel unit; and a histogram analyzing unit for analyzing the histogram analyzed by the histogram analyzing unit A comparison unit for comparing the calculated representative value with the set reference value, and a selection unit for selecting one image implementation method according to a result from the comparison unit And the liquid crystal display device. 4. The apparatus of claim 3, wherein the intermediate data generation unit receives the R, G, and B data by selection from the selection unit, extracts a motion vector between the current frame data (or original data) And a BDI unit for receiving the R, G and B data according to the selection from the selection unit and inserting the black data into the original data and outputting the inserted data. And the liquid crystal display device. A histogram is analyzed on a frame or pixel basis by receiving R, G, and B data from the outside, and the backlight is scanned and driven by selecting one of scanning backlight and MEDI according to the luminance characteristic, An image quality and brightness improving unit for inserting the image data into original data and outputting the same; A timing controller for generating correction data by rearranging R, G, and B data from the image quality and brightness improving unit, generating a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronizing signal from the outside, ; A data driver for selecting and outputting the gradation voltage according to the correction data from the timing controller; A gate driver for generating and outputting a gate on / off voltage in accordance with the control signal from the timing controller; And a liquid crystal panel that receives image data from the data driver and implements an image. The apparatus of claim 5, wherein the image quality and brightness enhancement unit receives the R, G, and B data from an external source, analyzes the histogram, compares a representative value from the analyzed histogram with a preset reference value, A scanning backlight / MEDI determination unit for determining whether to generate intermediate data according to a driving or motion vector, and a MEDI or a scanning backlight scheme according to a result of the scanning backlight / MEDI determination unit to select intermediate data to generate original data And a scanning backlight / intermediate data processing unit for outputting the image data by inserting or outputting the image data or for scanning the backlight. 7. The apparatus of claim 6, wherein the scanning backlight / MEDI determination unit comprises: a histogram analyzer for generating the histogram by arranging luminance components corresponding to gray levels through luminance analysis on a frame-by-frame basis; and a representative value calculation unit A comparator for comparing the representative value with the set reference value and outputting a control signal according to a result of the comparison, and a selector for specifying one path according to the control signal output from the comparator . 7. The apparatus according to claim 6, wherein the scanning backlight / intermediate data processing unit comprises: a scanning backlight unit for scanning the backlight when the representative value from the scanning backlight / MEDI determination unit is less than a reference value smaller than the gray level luminance corresponding to the maximum gray level; When the representative value from the backlight / MEDI determination unit is equal to or greater than the set reference value, the motion data of the frame data is extracted from the preceding frame data (or previous frame data), and the intermediate data by the motion vector is generated, And a MEDI unit for retaining and outputting the luminance of the original data. Analyzing a histogram by receiving R, G, and B data of a frame or pixel unit from the outside; Calculating a representative value of a tone value obtained by analyzing the histogram; Comparing the representative value with a reference value of the maximum gradation luminance; Inserting black data into the original data and outputting the original data when the representative value is less than or equal to the reference value; And Generating intermediate data based on the motion vector of the original data and the previous data, and inserting the intermediate data into the original data and outputting the generated intermediate data when the representative value is equal to or greater than the reference value. The method as claimed in claim 9, wherein the step of comparing the representative value with the reference value further comprises the step of generating a control signal according to a result of the comparison to select either the MEDI or the BDI method. A method of driving a device. Analyzing a histogram by receiving R, G, and B data of a frame or pixel unit from the outside; Calculating a representative value of a tone value obtained by analyzing the histogram; Comparing the representative value with a reference value smaller than a maximum gradation luminance; Scanning the backlight when the representative value is less than or equal to the reference value; And And generating intermediate data based on the motion vector of the original data and the previous data when the representative value is equal to or greater than the reference value and inserting the intermediate data into the original data and outputting the generated intermediate data. 12. The method of claim 11, wherein the step of comparing the representative value with a reference value further comprises the step of generating a control signal according to the comparison result and selecting one of a MEDI or a scanning backlight driving method A method of driving a liquid crystal display device.

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