KR20090060051A - Liquid crystal display device and drivign method thereof - Google Patents

Abstract

A liquid crystal display device and a driving method thereof are provided to improved image quality by processing an image at high speed through a histogram. An image and brightness improvement unit(200) receives R, G, and B data from the outside and analyzes the histogram by a frame or a pixel unit, and it selects one of BDI or MEDI according to brightness property. The image and brightness improvement unit inserts intermediate data into an original data by a selection method. A timing controller(111) re-arranges R, G, B data from the image and brightness improvement unit and generates a collection data, and it receives a vertical/horizontal synchronous signal from the outside and generates a new control signal which is synchronized with the correction data.

Description

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

The present invention relates to a liquid crystal display and a driving method thereof, and more particularly to R, G, B data in units of frames or pixels in order to simultaneously improve motion blur and luminance when a video is implemented in a panel capable of high-speed driving with respect to an input frame frequency. After the luminance analysis of the liquid crystal display device to implement the image by selecting any one of the motion estimation data insertion (MEDI) and black data insertion (BDI) (or MEDI and scanning backlight method) according to the brightness characteristics and It relates to the driving method.

 Entering the 21st century information society, various flat panel display devices that can reduce the weight and volume, which are disadvantages of cathode ray tubes, have emerged. Currently, flat panel displays include liquid crystal displays, field emission displays, plasma display panels, and light emitting displays.

Among them, the liquid crystal display device can be miniaturized compared to the cathode ray tube, and thus the use range of the liquid crystal display device is extended to desktop computers, notebook computers, office automation equipment such as copy machines, mobile phones, and the like.

However, such a liquid crystal display has a motion blur phenomenon in which an image is blurred when a moving image is implemented due to the signal voltage holding characteristic of the liquid crystal.

In this regard, the data characteristics of a cathode ray tube (CRT) and a liquid crystal display will be described with reference to FIGS. 1 to 7.

As shown in FIG. 1, the CRT emits a phosphor only during an initial very short time of one field period to display data, and an impulse type in which almost all of one field period remains at a pause interval. Display device. As a result, as shown in FIG. 2, a perceived image of a video perceived by a viewer in the CRT is clearly displayed.

In contrast, as shown in FIG. 3, in the liquid crystal display device, data is supplied to the liquid crystal during the scanning period in which the scan high voltage Vgh is supplied, and data supplied to the liquid crystal is maintained in the non-scanning period, which is most of one field period. do. Accordingly, as shown in FIG. 4, in the liquid crystal display, the display image is blurred due to the motion blur phenomenon.

This difference in perceptual image is due to the integral effect of the image which is temporarily persisted in the eye following the movement. Therefore, even if the response speed of the liquid crystal display is fast, the viewer sees a blurred screen due to a mismatch between eye movement and a static image of each frame.

In order to alleviate the motion blur of the conventional LCD, a method of reducing the holding time and inserting black data during a frame period has been proposed.

Unlike the general method in which one frame data is supplied for one frame period as shown in FIG. 5, the black data insertion method adjusts the holding time D1 to D5 of the frame data in each frame as shown in FIG. 6. By reducing and inserting the black data B1 to B5, the liquid crystal display is driven by a similar impulse type to alleviate the motion blur phenomenon.

However, the motion blur problem can be solved to some extent by the black data insertion method. However, since the data holding time of each frame is reduced and the black data is inserted, the luminance is higher in the black data insertion method than in the general method as shown in FIG. There is a problem of significantly lowering more than 30%.

On the other hand, in order to improve such a problem of brightness reduction, a method of generating new frame data as intermediate data using a motion vector has also been proposed.

In other words, the MEDI method sequentially extracts motion vectors of incoming images, predicts intermediate images, generates virtual images (or intermediate data), and inserts and outputs them between existing frame data and frame data. do.

However, MEDI is not able to implement all the images perfectly, and artifacts are generated due to an algorithm error when generating intermediate data.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is compatible with a black data generation unit (or a scanning backlight unit for scanning and driving a backlight) for generating and inserting black data, and the black data generation unit. The MEDI generation unit is configured, and the luminance data is analyzed in units of frames or pixels, and the black data is inserted (or the scanning backlight driving) and the intermediate data is generated by the motion vector according to the luminance characteristics to implement the image. A liquid crystal display and a driving method thereof are provided.

In order to achieve the above object, the liquid crystal display according to the first exemplary embodiment of the present invention receives R, G, and B data from the outside and analyzes the histogram on a frame or pixel basis, and analyzes the histogram. An image quality and luminance improving unit for outputting data by inserting intermediate data generated by selecting any one of BDI and MEDI according to luminance characteristics into original data; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving an external vertical / horizontal synchronization signal; ; A data driver which selects and outputs a corresponding gray 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 configured to receive pixel data from the data driver to implement an image.

In addition, the driving method of the liquid crystal display according to the first embodiment of the present invention comprises the steps of analyzing the histogram by receiving R, G, B data in units of frames or pixels from the outside; Calculating a representative value with respect to a gray value obtained by analyzing the histogram; Comparing the calculated representative value with any one reference value of the maximum gradation luminance; When the representative value is less than or equal to the reference value, inserting the black data into the original data and outputting the same, but increasing the luminance of the original data by 2 times; And when the representative value is greater than or equal to the reference value, generating intermediate data by the motion vector of the original data and the previous data, inserting the intermediate data into the original data, and outputting the intermediate data.

In addition, the liquid crystal display according to the second exemplary embodiment of the present invention receives the R, G, and B data from the outside and analyzes the histogram on a frame or pixel basis, and either the scanning backlight or the MEDI according to the luminance characteristics. An image quality and luminance improvement unit for selecting a method of driving the backlight or generating intermediate data and inserting the intermediate data into the original data and outputting the original data; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving an external vertical / horizontal synchronization signal; ; A data driver which selects and outputs a corresponding gray 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 configured to receive pixel data from the data driver to implement an image.

In addition, the driving method of the liquid crystal display according to the second embodiment of the present invention comprises the steps of analyzing the histogram by receiving R, G, B data in units of frames or pixels from the outside; Calculating a representative value with respect to a gray value obtained by analyzing the histogram; Comparing the calculated representative value with one reference value smaller than the maximum gray scale luminance; Driving the backlight when the representative value is less than or equal to the reference value as a result of the comparison; And when the representative value is greater than or equal to the reference value, generating intermediate data by the motion vector of the original data and the previous data, inserting the intermediate data into the original data, and outputting the intermediate data.

As a result of the above configuration, the LCD according to the present invention analyzes the histogram using R, G, and B data input from the outside in frame or pixel unit, and then compares the BDI (BDI) according to the comparison between the analysis value and the initial reference value. Or scanning backlight) and MEDI method to select one of the methods to process the image at high speed with respect to the input frame frequency, thereby improving the brightness and motion blur when the video is implemented, thereby improving the image quality.

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

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

As illustrated in FIG. 8, the liquid crystal display according to the first exemplary embodiment of the present invention receives R, G, and B data from the outside, analyzes the histogram in units of frames or pixels, and analyzes the histogram according to its luminance characteristics. Or an image quality and luminance improvement unit for outputting data by inserting intermediate data generated by selecting one of MEDI methods into original data; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving an external vertical / horizontal synchronization signal; ; A data driver which selects and outputs a corresponding gray 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 configured to receive pixel data from the data driver to implement an image.

First, the liquid crystal panel 120 is provided with a plurality of gate lines GL1 through GLn and a plurality of data lines DL1 through DLm that are insulated from each other and intersect with the gate lines GL1 through GLn. Liquid crystal cells are arranged in a matrix form for each unit pixel defined by the intersection of GL1 to GLn and the data lines DL1 to DLm. Each liquid crystal cell includes a thin film transistor connected to any one of the n gate lines GL1 to GLn and one of the m data lines DL1 to DLm.

On the other hand, the backlight 135 is composed of a plurality of lamps, such as Cold Cathode Fluorescent Lamp (CCFL) or External Electrode Fluorescent Lamp (EEFL), which are lit by AC high voltage, and the light provided from the lamps on the front side. It is sent to the liquid crystal panel 120 is located.

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

The power supply voltage generator 130 receives an AC voltage from the outside and generates a DC voltage of about 12V, and a DC-DC converter that generates various types of DC voltages using the DC voltage. DC convertor). Here, the DC-DC converter is formed by being integrated in a pulse width modulation integrated circuit (PWM IC), and is coupled to the peripheral circuit surrounding the PWM IC to form a common voltage (Vcom), a power supply voltage (Vdd), and a gate on / off. Off voltages Vgl and Vgh are generated.

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

In addition, the image quality and luminance improvement unit 200 is largely divided into the MEDI / BDI determination unit 210 and the intermediate data generation unit 220. In the MEDI / BDI determination unit 210, R, G, The B data is first analyzed by histogram on a frame (or pixel) basis to calculate a representative value, and the representative value is compared with the initial reference value of the LCD to determine (or select) an image realization method of either MEDI or BDI. The intermediate data generating unit 220 outputs data generated by inserting black data as intermediate data into the original data through the BDI unit according to the selected result, or outputs the current frame data to the original data through the MEDI unit. A motion vector is extracted between the previous frame data and the previous frame data, and the generated data is output by inserting intermediate data for each frame (or pixel) through the motion vector.

The timing controller 111 may include a data rearranging unit which supplies back to the data driver 120 correction data (Do DATA) in which the R, G, and B data rearranged from the image quality and luminance improvement unit 200 are rearranged. R, G, and B inputted by receiving the vertical / horizontal synchronization signals (Vsync, Hsync) from the interface 100 coupled to an external system (or device) and frequency-modulated from the image quality and luminance improvement unit 200. And a control signal generator for generating the data control signal of the data driver 116 and the gate control signal for controlling the gate driver 115 to synchronize with data. At this time, the timing controller 111 rearranges the data of R, G, and B to correspond to the gray scale information by using the logic voltage Vlog generated and sent from the power supply voltage generation unit 130.

The timing controller 111 is a gate control signal for controlling the gate driver 115 as a gate shift clock (GSC), a gate output enable (GOE), and a gate start pulse (Gate Start Pulse). GSC) is a signal for determining the time when the gate of the thin film transistor is turned on / off, GOE is a signal for controlling the output of the gate driver 115, GSP is one vertical This signal informs the first driving line of the screen among the synchronization signals.

In addition, the timing controller 111 is a data control signal for controlling the data driver 116, a source sampling clock (SSC), a source output enable (SOE), a source start pulse (Source Start Pulse: SSP), polarity reverse (POL), data polarity selection (REV), odd / even pixel data (Odd / Even Data) signals, and the like.

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

The gate driver 115 receives the gate voltages Vgl and Vgh generated by the power supply voltage generator 130 and sequentially applies the gate voltages Vgl to the gate lines GL1 to GLn according to control signals of the timing controller 111. , Vgh is supplied to drive the thin film transistors connected to the corresponding gate lines GL1 to GLn.

In addition, the data driver 116 converts the R, G, and B data output from the timing controller 111 into pixel voltages, which are analog signals, during one horizontal period in which the gate voltages are supplied to the respective gate lines GL1 to GLn. The pixel voltage of one horizontal line is supplied to the data lines DL1 through DLm. In this case, the data driver 116 converts the R, G, and B data into pixel voltages using the gamma voltage supplied from the gamma voltage gray scale circuit (not shown).

More specifically, the data driver 116 includes a data register into which data RGB output from the timing controller 111 is input, a shift register for generating a sampling clock, the shift register, and m data lines. Gamma gradation voltage circuit for dividing the first and second latches and the gamma reference voltages Vref connected to the digital to analog converters (DACs), digital / It includes an analog converter and an output.

Here, the data register temporarily stores the data RGB from the timing controller 111 and 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 to transfer the carry signal CAR to the next shift register.

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

After latching the digital data RGB input from the first latch, the second latch enables the data to be simultaneously output in response to the latched digital video data RGB in response to the SOE signal from the timing controller 130.

The gamma gradation voltage circuit divides the gamma reference voltages Vref of various levels generated by the reference voltage generation unit 131 to generate gamma gradation voltages corresponding to each gradation 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 in response to the video data RGB from the second latch. Of course, the gradation voltage here is selected and output as either one of positive polarity (+) and negative polarity (−) in accordance with the polarity control signal POL from the timing controller 111.

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

Through this process, the thin film transistor on the liquid crystal panel 120 receives 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. The liquid crystal cell controls the transmittance of the light provided from the backlight 135 by driving the liquid crystal positioned between the common electrode and the pixel electrode in response to the pixel voltage. Image realization is achieved by the transmittance of transmitted light.

FIG. 9 is a sub-block diagram illustrating the image quality and luminance improvement unit of FIG. 8.

As shown in FIG. 9, the image quality and luminance improving unit 200 according to the present invention analyzes the histogram by receiving R, G, and B data from the outside as described above, and compares the representative value of the histogram with the set reference value. The MEDI / BDI determination unit 210 determines the intermediate data generation method according to the comparison result, and generates the intermediate data by either MEDI or BDI method according to the result of the MEDI / BDI determination unit 210. It is divided into the intermediate data generation unit 220 to insert the data into the output.

Here, the MEDI / BDI determination unit 210 arranges the luminance components corresponding to gray levels by luminance analysis, for example, for each frame, to generate a histogram, and representative values of the histograms, for example, average and deviation. And a representative value calculator 213 for calculating any one of the values corresponding to the median value, the mode value, the maximum value, the minimum value, and the like, and any reference value smaller than the maximum gradation luminance, for example, normally black. In the mode, when 255 levels of grayscale correspond to full-white, the comparison result is compared with reference values corresponding to 1/2, 1/3, etc. of the maximum grayscale luminance corresponding to the full white. A comparator 215 for outputting a control signal and a selector 217 for designating one path according to the control signal output from the comparator 215 are provided.

In addition, when the representative value from the MEDI / BDI determination unit 210 is less than or equal to the initial reference value, the intermediate data generator 220 judges the frame as black, inserts black data into the original data, and outputs the original data. When the representative value from the BDI unit 223 and the MEDI / BDI determination unit 210 are greater than or equal to the initially set reference value, the frame data is determined to be white and the previous frame data (or the previous frame) is increased. And the MEDI unit 221 which extracts the motion vector from the data), generates intermediate data based on the motion vector, inserts the interpolated data into the original data, and outputs the same while maintaining the luminance of the original data.

FIG. 10 is a diagram illustrating a data processing state when a BDI unit is selected in the MEDI / BDI determination unit and the intermediate data generation unit of FIG. 9, and FIG. 11 is a MEDI unit in the MEDI / BDI determination unit and the intermediate data generation unit of FIG. 9. It is a figure which shows the data processing state when it is selected.

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

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

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

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

Then, the representative value calculator 213 calculates a representative value of the histogram analyzed by the histogram analyzer 211. In other words, the representative value calculator 213 generates one representative histogram from the plurality of histograms analyzed by the histogram analyzer 211.

In addition, the comparison unit 215 compares the representative value with a predetermined reference value, as described above, and any reference value X smaller than the maximum gradation luminance, and then when the representative value becomes equal to or greater than the reference value X. If the representative value is larger than the reference value X, the corresponding unit frame is determined to be almost white, and the corresponding control signal is provided to the selector 217. For example, the comparison unit 215 may generate and send a control signal of "00" to drive the BDI unit 223.

Then, the selector 217 opens a channel for selecting the BDI 223 according to the above control signal. Of course, the selector 217 may be configured as a switching circuit or a multiplexer that is turned on / off according to a control signal.

Then, the BDI unit 223 uses the correction data of R, G, and B realigned from the timing controller through the selection unit 217 as shown in FIG. 10 (c) for 1/120 second [sec]. Correction data of R, G, and B units, that is, original data, are output, followed by black data as intermediate data for 1/120 second [sec].

In this case, since the luminance decreases to 1/2 due to the influence of the black data, the luminance is doubled by resetting (or gamma correction) the grayscale value for the original data to compensate for this.

As a result, the present invention analyzes the histogram for each unit frame and inserts black data as intermediate data only when it is selected by its luminance characteristic. It is possible to improve the luminance.

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

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

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

As a result, when the gray value of the frame data is full white as the gray level corresponding to 255 levels of 256 gray levels in the normally black mode as shown in FIG.

Then, the representative value calculator 213 calculates the representative value of the histogram analyzed by the histogram analyzer 211. In other words, the representative value calculator 213 generates one representative histogram from the plurality of histograms analyzed by the histogram analyzer 211.

Then, the comparison unit 215 compares the representative value with a predetermined reference value X and any reference value X smaller than the maximum gradation luminance as mentioned above, and then the representative value is the reference value X. If abnormal (or the representative value is larger than the reference value X), the corresponding unit frame is determined to be almost white, and the 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 selector 217 opens the path for selecting the MEDI 221 according to the above control signal. As described above, the selector 217 may be configured as a switching circuit or a multiplexer that is turned on / off according to a control signal.

As shown in FIG. 11C, the MEDI unit 221 uses frame correction units of R, G, and B provided by rearranging from the timing controller through the selection unit 217 in frame units for 1/120 seconds. The correction data of R, G, and B, that is, the original data, are output, followed by extracting the motion vector through the previous data stored in the frame memory separate from the current original data as intermediate data for 1/120 sec. Intermediate data is generated using motion vectors and inserted into the original data to output intermediate data. At this time, as the intermediate data, a method of generating, inserting and outputting the same data as the original data into the original data by data doubling may be possible.

In both cases, since the original data is not affected by the luminance due to the intermediate data, the data is output while maintaining the luminance of the original data.

As a result, since the present invention generates the intermediate data only by the MEDI method only when it is partially selected by the luminance characteristic of each unit frame, the intermediate data is generated more than when generating the intermediate data by implementing all the frame data only by the MEDI method. This can reduce the errors that occur at the time.

However, when analyzing the luminance characteristics for each unit frame as described above and selecting one of MEDI and BDI according to the result, the image may not only take a long time in the image processing, but also the image may be implemented. The contrast ratio for a particular object in the visual image may be somewhat reduced.

Considering this point, in the present invention, although not shown in a separate drawing, the histogram is analyzed for each pixel unit of R, G, and B, and the representative value is calculated from the gray value of the pixels distributed in the histogram and compared with the reference value. Depending on the result, the method of selecting either MEDI or BDI cannot be excluded.

In this case, the system processing speed will not be significantly different as compared with the frame-by-frame processing method described above. However, even in such a pixel-based image processing method, an improvement effect of motion blur on a specific object of an image may be slightly reduced when a video is implemented.

Except for this point, the pixel-based data processing method is not very different from the frame-based processing method, so other details will be replaced with the above-mentioned contents.

FIG. 12 is a block diagram of a liquid crystal display according to a second embodiment of the present invention, and FIG. 13 is a sub-block diagram showing the image quality and luminance improvement of FIG.

12 and 13, the liquid crystal display according to the second exemplary embodiment of the present invention receives histograms from the outside and analyzes histograms in units of frames or pixels, and luminance characteristics thereof. An image quality and luminance improvement unit configured to select one of the scanning backlight and the MEDI to drive the backlight or to generate intermediate data and insert the intermediate data into the original data; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving an external vertical / horizontal synchronization signal; ; A data driver which selects and outputs a corresponding gray 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 configured to receive pixel data from the data driver to implement an image.

First, the liquid crystal panel 320 is provided with a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm that are insulated from each other and intersect with the gate lines GL1 to GLn. Liquid crystal cells are arranged in a matrix form for each unit pixel defined by the intersection of GL1 to GLn and the data lines DL1 to DLm. Each liquid crystal cell includes a thin film transistor connected to any one of the n gate lines GL1 to GLn and one of the m data lines DL1 to DLm.

On the other hand, the backlight 335 is composed of a plurality of lamps, such as CCFL or EEFL is turned on by the high AC voltage, the plurality of lamps are divided into at least two groups or areas to drive. In this case, the lamps are partially driven to provide light by synchronizing with the time point at which the image is implemented on the liquid crystal panel 320 positioned on the front surface.

The lamp driver 333 receives a DC voltage of about 24V from the power supply voltage generator 330, converts the DC voltage into a DC AC waveform, and converts the AC waveform into an AC AC voltage having a high voltage, and applies it to the backlight 335. The backlight is driven by receiving the control signal from the timing controller 311.

The power supply voltage generator 330 includes an AC-DC rectifier for generating a DC voltage of about 12V by receiving a commercial voltage from the outside, and a DC-DC converter for generating various types of DC voltages using the DC voltage. It is composed. 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 voltage (Vgl, Vgh) are combined with the peripheral circuit surrounding the PWM IC. And so on.

The reference voltage generation unit 331 divides the power supply voltage Vdd provided from the power supply voltage generation unit 330 to generate gamma reference voltages Vref of various levels, and converts the gamma reference voltage Vref back to a data driver ( 316 to a gamma voltage voltage circuit (not shown). In this case, a plurality of gamma reference voltages Vref having various levels are generated through a plurality of resistors connected in series.

In addition, the image quality and luminance improvement unit 400 is largely divided into the scanning backlight / MEDI determination unit 410 and the scanning backlight / intermediate data processing unit 420. In the scanning backlight / MEDI determination unit 410, R from the outside is used. First, the G and B data are analyzed by histogram on a frame (or pixel) basis to calculate a representative value, and the representative value is compared with an initial reference value of the liquid crystal display device to determine a method of driving an image of scanning backlight or MEDI. According to the selected result, the scanning backlight / intermediate data processor 420 controls the lamp driver 333 through the scanning backlight unit according to the selected result so that the backlight is dividedly driven or the current frame data and the previous frame to the original data through the MEDI unit. Created by extracting a motion vector between data and inserting intermediate data for each frame (or pixel) through the motion vector. Will output the data.

The timing controller 311 is a data rearranging unit which rearranges the inputted R, G, and B data and supplies it back to the data driver 316 by frequency-sequencing from the image quality and luminance improvement unit 400 and an external system (or device). The gate driver to receive vertical / horizontal synchronization signals (Vsync, Hsync) from the interface 300 coupled to each other and to synchronize the inputted R, G, and B data by frequency-multiplying from the image quality and luminance improvement unit 400. And a control signal generator for generating the data control signal of the data driver 316 and the gate control signal for controlling 315. At this time, the timing controller 311 rearranges the data of R, G, and B so as to correspond to the gray scale information by using the logic voltage Vlog generated and sent from the power supply voltage generator 330.

The timing controller 311 first generates a gate shift clock (GSC), a gate output enable (GOE), a gate start pulse (GSP), etc. as a gate control signal for controlling the gate driver 315. The GSC is a thin film transistor. The signal determines the time when the gate is turned on / off, the GOE is a signal for controlling the output of the gate driver 315, and the GSP is a signal indicating the first driving line of the screen among one vertical synchronization signal.

In addition, the timing controller 311 is a data control signal for controlling the data driver 316 as a source sampling clock (SSC), a source output enable (SOE), a source start pulse (SSP), a liquid crystal polarity inversion (POL), and a data polarity. Select (REV), odd / even pixel data signals, etc. are generated.

The gate driver 315 receives the gate voltages Vgl and Vgh generated by the power supply voltage generator 330 and sequentially applies the gate voltages Vgl to the gate lines GL1 to GLn according to the control signal of the timing controller 311. , Vgh is supplied to drive the thin film transistors connected to the corresponding gate lines GL1 to GLn.

In addition, the data driver 316 converts the corrected R, G, and B data (Do DATA) output from the timing controller 311 into a pixel voltage, which is an analog signal, so that a gate voltage is applied to each gate line GL1 to GLn. The pixel voltage for one horizontal line is supplied to the data lines DL1 to DLm during one horizontal period. In this case, the data driver 316 converts the R, G, and B data into pixel voltages by using the gamma voltage supplied from the gamma voltage gray scale circuit (not shown).

Through this process, the thin film transistor on the liquid crystal panel 320 receives 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. 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. Image realization is achieved by the transmittance of transmitted light.

FIG. 13 is a sub-block diagram illustrating the image quality and luminance improvement unit of FIG. 12.

As shown in FIG. 13, the image quality and luminance improvement unit 400 according to the present invention receives R, G, and B data from the outside, analyzes the histogram, and compares the representative value from the histogram with the set reference value. According to the result, the lamp driving unit is controlled to drive the backlight, or the scanning backlight / MEDI determining unit 410 and the scanning backlight / MEDI determining unit 410 determine the generation of intermediate data according to the motion vector. Alternatively, it is divided into a scanning backlight / intermediate data processor 420 which selects one of the scanning backlight methods to generate intermediate data or to drive the backlight.

Here, the scanning backlight / MEDI determiner 410 arranges the luminance component corresponding to the gray level through luminance analysis, for example, for each frame, and generates a histogram, and a representative value of the histogram such as an average, A representative value calculator 413 that calculates any one of the deviation, the median, the mode, the maximum value, the minimum value, and the like, and any reference value smaller than the maximum gray level luminance, such as 256 in normal black mode. When the gray level of 255 levels among the gray scales corresponds to full-white, a comparison unit for comparing the reference values corresponding to 1/2, 1/3, etc. of the gray scale luminance corresponding to the full white, and outputting a control signal according to the comparison result ( 415 and a selector 417 in which one path is designated according to the control signal output from the comparator 415.

In addition, the scanning backlight / intermediate data processor 420 controls the lamp driver to scan the backlight when the representative value from the scanning backlight / MEDI determination unit 410 is equal to or less than the initial reference value, and the scanning backlight unit 423 to scan the backlight. When the representative value from the backlight / MEDI determination unit 410 is equal to or larger than the initial reference value, the frame data is judged to be white and the motion vector is extracted from the previous frame data (or previous frame data) stored in a separate memory. The MEDI unit 421 generates intermediate data by vector, inserts it into original data, and outputs the same, while maintaining the brightness of the original data as it is.

Of course, the scanning backlight technology of the present invention divides the backlight installed on the back of the liquid crystal panel into a plurality of regions, and implements impulse driving by turning on / off lamps in each region according to a control signal from the outside. Indicates.

However, the present invention further provides a scanning backlight technology, for example, by inserting black data between the existing frame data and the frame data in the same way as the BDI method described above, and simultaneously turning on / off the lamps of the respective regions which are divided and driven on the back of the liquid crystal panel. It may also include a way of controlling. For example, when black data is implemented, the lamp is temporarily turned off to drive the backlight.

1 is a diagram illustrating the light emission characteristics of a CRT.

2 is a diagram illustrating a perceptual image with a cathode ray felt by a viewer;

3 is a view showing light emission characteristics of a liquid crystal display device;

4 is a diagram illustrating a perceptual image of a liquid crystal display device felt by a viewer;

5 is a diagram illustrating a data alignment state in a normal state;

FIG. 6 is a diagram showing a data arrangement in which black data is inserted into the entire gradation area; FIG.

7 is a diagram comparing the luminance in the normal state with the luminance in the black data insertion;

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

9 is a sub-block diagram illustrating the image quality and luminance improvement unit of FIG. 8.

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

FIG. 11 is a diagram illustrating a data processing state when the MEDI unit is selected in the MEDI / BDI determination unit and the intermediate data generation unit of FIG. 9; FIG.

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

FIG. 13 is a sub-block diagram illustrating the image quality and luminance improvement unit of FIG. 12.

Claims (12)

Analyze histogram in frame or pixel unit by receiving R, G, and B data from the outside, and select intermediate method generated by selecting either BDI or MEDI according to its luminance characteristics. An image quality and luminance improvement unit for inserting original data into outputting data; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronization signal from the outside; A data driver which selects and outputs a corresponding gray voltage according to the corrected data information from the timing controller; A gate driver generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel configured to receive pixel data from the data driver to implement an image. The MEDI / BDI determination method of claim 1, wherein the image quality and luminance improvement unit receives R, G, and B data from an external source, analyzes a histogram, and compares the result with a set reference value to determine a method of generating intermediate data according to the comparison result. And an intermediate data generation unit for generating intermediate data using any one of MEDI and BDI methods according to a result of the MEDI / BDI determination unit. The apparatus of claim 2, wherein the MEDI / BDI determination unit analyzes a histogram using R, G, and B data applied from the outside in a frame or pixel unit, and a representative of the gray values analyzed by the histogram analyzer. A representative value calculating unit calculating a value, a comparing unit comparing the calculated representative value with an initially set reference value, and a selecting unit selecting one image realization method according to the result from the comparing unit. A liquid crystal display device. 3. The method of claim 2, wherein the intermediate data generation unit receives the R, G, B data by selection from the selection unit and extracts a motion vector between the current frame data (or original data) and the previous frame data, and then the motion vector. MEDI unit for generating intermediate data by inserting into the original data and outputting it, and BDI unit for inserting and outputting black data into the original data by receiving R, G, and B data according to the selection from the selection unit. Liquid crystal display device characterized in that. Analyze the histogram on a frame or pixel basis by receiving external R, G, and B data, and select one of the scanning backlight or MEDI according to the luminance characteristics to drive the backlight or to perform intermediate data. Improved image quality and luminance to generate and insert into the original data to output; A timing controller for rearranging the R, G, and B data from the image quality and luminance improvement unit to generate correction data, and generating and outputting a new control signal synchronized with the correction data by receiving a vertical / horizontal synchronization signal from the outside; A data driver which selects and outputs a corresponding gray voltage according to the corrected data information from the timing controller; A gate driver generating and outputting a gate on / off voltage according to a control signal from the timing controller; And a liquid crystal panel configured to receive pixel data from the data driver to implement an image. The method of claim 5, wherein the image quality and luminance improvement unit receives an R, G, and B data from an external device, analyzes the histogram, and compares the representative value from the histogram with the set reference value. The scanning backlight / MEDI judging unit which determines the generation of the intermediate data according to the vector, and either the MEDI or the scanning backlight method is selected according to the result of the scanning backlight / MEDI judging unit to generate the intermediate data and insert the intermediate data into the original data. Or a scanning backlight / intermediate data processing unit for driving a backlight for driving the backlight. The apparatus of claim 6, wherein the scanning backlight / MEDI determiner comprises: a histogram analyzer configured to generate a histogram by arranging luminance components corresponding to gray levels through luminance analysis for each frame; a representative value calculator configured to calculate a representative value of the histogram; And a comparison unit configured to compare the representative value with a preset reference value and output a control signal according to the comparison result, and a selection unit to which one path is designated according to the control signal output from the comparison unit. Liquid crystal display device. The scanning backlight unit of claim 6, wherein the scanning backlight / intermediate data processor is configured to drive the backlight when the representative value from the scanning backlight / MEDI determination unit is less than or equal to a reference value smaller than the gradation luminance corresponding to the maximum gradation; If the representative value from the backlight / MEDI determination unit is equal to or greater than the initial reference value, the frame data is extracted from the motion vector with the previous frame data (or previous frame data), and then intermediate data based on the motion vector is generated and inserted into the original data. However, the liquid crystal display device comprising a MEDI unit for outputting while maintaining the luminance of the original data as it is. Analyzing a histogram by receiving R, G, and B data in units of frames or pixels from the outside; Calculating a representative value with respect to a gray value obtained by analyzing the histogram; Comparing the calculated representative value with any one reference value of the maximum gradation luminance; When the representative value is less than or equal to the reference value, inserting the black data into the original data and outputting the same, but increasing the luminance of the original data by 2 times; And And generating intermediate data based on motion vectors of the original data and the previous data, inserting the intermediate data into the original data when the representative value is greater than or equal to the reference value, and outputting the intermediate data. The liquid crystal display of claim 9, wherein the comparing of the representative value and the reference value further comprises generating a control signal and selecting one of MEDI and BDI methods according to the comparison result. Driving method. Analyzing a histogram by receiving R, G, and B data in units of frames or pixels from the outside; Calculating a representative value with respect to a gray value obtained by analyzing the histogram; Comparing the calculated representative value with one reference value smaller than the maximum gray scale luminance; Driving the backlight when the representative value is less than or equal to the reference value as a result of the comparison; And And generating intermediate data based on motion vectors of the original data and the previous data, inserting the intermediate data into the original data when the representative value is greater than or equal to the reference value, and outputting the intermediate data. The liquid crystal display of claim 11, wherein the comparing of the representative value and the reference value further comprises generating a control signal according to a result of the comparison and selecting one of a MEDI and a scanning backlight driving method. Method of driving display device.

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