KR101408254B1 - Response time improvement apparatus and method for liquid crystal display device - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a technique for obtaining a fast response characteristic without causing a blur phenomenon or a drag phenomenon of an image in a liquid crystal display device. According to the present invention, an edge area in which motion of an input image is generated is detected, and the overdrived data of the area is divided into excellent and odd numbers and added to each other. And allocates black data and overflow data to the pixels of the edge areas of the remaining frames; And a data driver for outputting the pixel signals corresponding to the data processed in the timing controller to the respective data lines of the liquid crystal panel.

Response time, blur, dragging

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a response time improving device and a liquid crystal display device,

The present invention relates to a technique for improving image quality in a liquid crystal display device, and more particularly, to a device and method for improving response time of a liquid crystal display device capable of obtaining a quick response characteristic without causing a blur phenomenon or a drag phenomenon .

In recent years, as information technology (IT) has evolved, display has become more important as a visual information delivery medium. In order to prevail in the future, it is necessary to meet requirements such as low power consumption, thinning, light weight, and high image quality.

2. Description of the Related Art A liquid crystal display (LCD), which is a typical display device of a flat panel display, is an apparatus for displaying an image using optical anisotropy of a liquid crystal. Because of its advantages such as thinness, small size, low power consumption and high picture quality, Ray Tube (CRT)).

2. Description of the Related Art In general, a liquid crystal display device is a display device that supplies image information individually to pixels arranged in a matrix form, and can display a desired image by adjusting light transmittance of the pixels. Therefore, the liquid crystal display device includes a liquid crystal panel in which pixels, which are minimum units for realizing an image, are arranged in an active matrix form, and a driving unit for driving the liquid crystal panel. In addition, since the liquid crystal display device can not emit light by itself, a backlight unit for supplying light to the liquid crystal display device is provided.

Currently, various technologies are being studied in order to improve the draw-in phenomenon in the LCD product, and a typical example is an over driving circuit (ODC).

The overdriving technique is a method for improving the response speed of a liquid crystal by charging a voltage charged in a pixel faster than the conventional method. The overdriving technique compares pixel data of a current frame with pixel data of a previous frame to check the degree of data change, Accordingly, a voltage higher or lower than the original voltage is applied for one field (frame).

FIG. 1 is a block diagram of an overdriving apparatus for a conventional liquid crystal display device. As shown in FIG. 1, the field memory 11 stores data of a previous field. A lookup table (12) storing data for performing overdriving according to a difference between data of a current field and data of a previous field stored in the field memory (11); And a data selector 13 for selecting and outputting currently input data or selecting and outputting output data of the lookup table 12. The operation of the data selector 13 will be described below.

The data of the previous field stored in the field memory 11 is compared with the data of the current field and the degree of change of the data is compared with the data of the current field stored in the field memory 11. [ And reads and outputs data for overdrive from the look-up table 12 according to the confirmation result.

The data selector 13 selects and outputs data of a currently input field, and when data for performing overdrive is output from the lookup table 12, the data selector 13 selects and outputs the data.

At this time, the data driver (not shown in the figure) outputs the data voltage corresponding to the over-driven gray level value outputted from the data selector 13 to the data line of the liquid crystal panel.

2A shows a principle of driving data in a liquid crystal display device in general. For example, when data (luminance) inputted to a series of pixels is 200, 200, 15, 15, 15, 200, .

FIG. 2B illustrates the principle of overdriving data for a liquid crystal display device. For example, when the data input to a series of pixels is 200, 200, 15, 15, 15, and 200 as described above, The data of the third pixel is shifted from 15 to 0, and the data of the last pixel is shifted from 200 to 255 to be output.

However, when the overdriving technique of the conventional liquid crystal display device is used, a blur and a dragging phenomenon are generated in a moving image, which makes it difficult to obtain a quick response characteristic, thereby deteriorating the image quality.

Accordingly, an object of the present invention is to provide a liquid crystal display device capable of modulating the data of an edge portion of a motion image appropriately to obtain a quick response characteristic without causing blurring or dragging.

According to an aspect of the present invention, there is provided a method of detecting an edge region in which motion of an input image is generated, separating the overdrived data of the region into an excellent and a radix, adding the results to each other, A timing controller for assigning black data and overflow data to pixels of an edge region of one frame and pixels of an edge region of the other frame; And a data driver for outputting pixel signals corresponding to the data processed in the timing controller to the respective data lines of the liquid crystal panel.

According to another aspect of the present invention, there is provided a method of driving a display device, the method comprising: converting input image data to overdriving data; Detecting an edge region in which motion is generated in an input image; The overdrived data of the edge area in which the motion is detected is divided into excellent and odd numbers and added to each other, and the result is assigned to a corresponding pixel in one of the odd or odd frames, and black data or over And a step of allocating the flow data.

The present invention detects an edge area in which motion of an input image is generated, separates the data of the edge area in which the motion has been generated from the overdrived data into excellent and odd numbers, adds the results to each other, Is assigned to the corresponding pixel of the frame and the black data or the overflow data is assigned to the corresponding pixel of the remaining frame so that blurring of the image can be achieved without causing a drag phenomenon and a quick response characteristic can be obtained .

In addition, there is an effect of preventing the blurring phenomenon of the image from being dragged while improving the response speed without causing any extra cost.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a block diagram showing an embodiment of an apparatus for improving the response characteristic of a liquid crystal display according to the present invention. As shown in FIG. 3, a gate control signal GDC and a data control signal DDC for controlling are output An edge region in which the motion of the input image is generated is detected and the overdrived data of the region is divided into an excellent and an odd number and added to each other and the result is assigned to a corresponding pixel in one of the frames of the odd or odd frame, A timing controller 31 for allocating and outputting black data or overflow data to corresponding pixels of the remaining frames; A gate driver 32 for outputting a gate signal to each gate line GL1 to GLn of the liquid crystal panel 34 in response to a gate signal control signal supplied from the timing controller 31; In supplying data voltages to the data lines DL1 to DLm of the liquid crystal panel 34 in response to the data signal control signal supplied from the timing controller 31, A data driver 33 for outputting a corresponding pixel signal; And a liquid crystal panel 34 for displaying an image by providing liquid crystal cells driven by the gate signal and the pixel signal in a matrix form.

The timing controller 31 includes an overdrive unit 31A for comparing the current field with the data of the previous field to check the degree of change of the data, reading out the overdrive data from the lookup table, and outputting the overdrive data; A field memory 31B in which data of a field inputted immediately before is stored; The data stored in the field memory 31B and the data of the currently input field are received and the motion speed and the pattern of the adjacent front and rear interframe images are detected, A motion and edge detection unit 31C for outputting the motion and edge detection signals to the motion detection unit 31D; The data of the edge area in which the motion has been generated is divided into superior and odd numbers and added to each other, and the result is assigned to a corresponding pixel in one of the odd or odd frames, And a data modulation unit 31D for allocating data or overflow data.

The operation of the present invention thus constructed will be described in detail with reference to FIGS. 3 to 4.

The timing controller 31 receives the gate control signal GDC for controlling the gate driver 32 and the data driver 33 using the vertical and horizontal synchronizing signals Hsync and Vsync supplied from the system and the clock signal CLK, And outputs a data control signal DDC for controlling the data control signal DDC. In addition, the timing controller 31 samples digital pixel data (RGB) input from the system, rearranges the digital pixel data, and supplies the same to the data driver 33.

The gate control signal GDC includes a gate start pulse GSP, a gate shift clock GSC and a gate-out enable signal GOE. The data control signal DDC includes a source start pulse SSP, (SSC), a source-out enable (SOE), and a polarity signal (POL).

The gate driver 32 sequentially supplies the gate signal to the gate lines GL1 to GLn in response to the gate control signal GDC input from the timing controller 31, ) Are turned on. Accordingly, the pixel signals supplied through the data lines DL1 to DLm are stored in the respective storage capacitors C _ST through the thin film transistors TFT.

The data driver 33 converts the pixel data RGB into an analog pixel signal (data signal or data voltage) corresponding to the gray level value in response to the data control signal DDC input from the timing controller 31 And supplies the converted pixel signals to the data lines DL1 to DLm on the liquid crystal panel 34. [

In more detail, the data driver 33 shifts the source-strobe pulse SSP according to the source shift clock to generate a sampling signal. The data driver 33 sequentially receives and latches the pixel data RGB in units of a predetermined unit in response to the sampling signal. The data driver 33 converts the latched pixel data RGB into analog pixel signals and supplies them to the data lines DL1 to DLm.

The liquid crystal panel 34 is formed in each crossing portion of the plurality of liquid crystal cells (C _LC) arranged in a matrix, a data line (DL1~DLm) and gate line (GL1~GLn) each of the liquid crystal cell (C _LC (TFT) connected to each of the TFTs. The thin film transistor TFT is turned on when a gate signal is supplied from the gate line GL and supplies a pixel signal supplied through the data line DL to the liquid crystal cell C _LC . The thin film transistor TFT is turned off when a gate off signal is supplied through the gate line GL, so that the pixel signal charged in the liquid crystal cell C _LC is maintained. The liquid crystal cell C _LC includes a common electrode and a pixel electrode connected to the thin film transistor TFT via a liquid crystal. The liquid crystal cell C _LC further includes a storage capacitor C _ST to maintain the charged pixel signal stably until the next pixel signal is charged. The storage capacitor C _ST is formed between the pixel electrode and the previous gate line. In the liquid crystal cell C _LC , the alignment state of the liquid crystal having dielectric anisotropy is varied according to the pixel signal charged through the thin film transistor (TFT), and thus the light transmittance is adjusted to realize the gradation.

A process for eliminating the blurring or dragging phenomenon of the moving picture during over-driving according to the present invention in the timing controller 31 will be described in detail as follows.

In the timing controller 31, the overdrive unit 31A performs overdriving for the input data according to the normal overdriving technique as shown in FIG. That is, the data of the previous field stored in the field memory is compared with the data of the currently inputted field to check the degree of change of the data, and the data for overdrive is read out from the lookup table according to the result of the check.

FIG. 4 exemplarily shows a moving picture screen in which the Arabic numeral '1' is displayed in order to explain the present invention. FIG. 5 (a) shows a moving picture processed by the overdriving unit 31A Overdriving results. That is, when the series of pixel data is 200, 200, 15, 15, 15, and 200, the data of the second pixel is 200 → 255, the data of the third pixel is 15 → 0, 255 is over-driven.

The motion and edge detecting unit 31C separates data (DATA IN) of the currently input field and data (luminance data) stored in the field memory 31B into m × n blocks based on the screen area as shown in FIG. The motion speed and the pattern are recognized by comparing the data of the corresponding block between the adjacent front and rear frames. When separating the screen area as described above, the area of 2 horizontally and vertically 2 horizontally is selected to include the overlap between the areas. At the same time, the motion and edge detecting unit 31C detects the edge of the image.

At this time, the motion and edge detecting unit 31C appropriately changes the size (area) of the edge portion of the image according to the motion speed of the image. For example, if the moving speed of the screen is V, the edge size of the image is S, and the proportional constant is α: 0 to 1, S 'is represented by the following equation (1).

 S =? * V (mm / sec)

Then, the motion and edge detecting unit 31C outputs the motion speed, pattern, and edge information of the moving image detected as described above to the data modulating unit 31D.

Accordingly, the data modulating unit 31D modulates and outputs data on the basis of motion speed, pattern and edge information detected by the motion and edge detecting unit 31C with respect to moving pictures as shown in FIG. 4 as follows do.

That is, the data modulating section 31D separates the pixel data of the edge region in which motion has been detected from the overdrived frame data by the overdrive section 31A into excellent and odd numbers, adds the results to each other, The motion of one frame out of the odd frame is assigned to the pixel of the generated edge region. At this time, if an overflow occurs in the result of addition, black data 0 is allocated to the remaining frames or overflow data is allocated.

For example, when a series of data over-driven by the over-driving unit 31A is as shown in FIG. 5A, the data modulating unit 31D outputs data 0 of the corresponding pixel in which motion and edge are detected, 15 is added, the result 15 is assigned to the corresponding pixel of the odd frame, and black data 0 is assigned to the corresponding pixel of the odd frame (see Fig. 5 (b)).

Similarly, the data modulating unit 31D adds the data 15 and 255 of the corresponding pixel in which the motion and the edge are detected, assigns the data 255 of the highest level among the result 270 to pixels of the odd frame, The flow data 15 is allocated (refer to FIG. 5 (b)).

For reference, the reason why the pixel data of the edge region in which motion is detected is divided into excellent and odd numbers as described above, considering that the LCD device is not a pulse type display device but a Hold type display device This is to insert black to visually refresh the luminance information quickly.

In the above description, the pixel data of the edge region in which motion has been detected is divided into excellent and odd numbers, added to each other, and the result is selected as either an odd or odd frame, The present invention is not limited thereto.

For example, pixel data of an edge region in which motion has been detected is divided into excellent and odd numbers, added to each other, and the result is selected as either an odd or odd frame, and the pixel of the edge region And then selects a frame that has not been selected immediately before, and allocates the selected odd-numbered frame to the pixels of the edge region where the motion has been generated in the selected frame, so that the resultant value can be assigned.

As a result, by assigning the luminance data dispersed in the edge portion of the halftone motion image intensively to either the odd or odd number of pixels, it is possible to obtain a quick response characteristic without causing blurring or dragging of the moving picture in overdriving .

1 is an over-driving block diagram of a liquid crystal display device according to the related art.

FIG. 2A is an exemplary view showing a principle of generally driving data in a liquid crystal display; FIG.

2B is an exemplary view showing a principle of overdriving data in a liquid crystal display device.

3 is a block diagram of an apparatus for improving response time of a liquid crystal display according to the present invention.

4 is an exemplary view of a moving picture screen;

FIG. 5A is an exemplary view showing an overdriving result in the present invention. FIG.

FIG. 5B is an exemplary view of a data processing result of an edge portion in which motion is detected in the present invention; FIG.

FIG. 6 is a diagram illustrating an example in which a screen area is divided into m × n in order to detect a motion speed and a pattern in the present invention; FIG.

DESCRIPTION OF THE REFERENCE SYMBOLS

31: Timing controller 31A: Overdriving part

31B: field memory 31C: motion and edge detector

31D: data modulation unit 32: gate driver

33: data driver 34: liquid crystal panel

Claims (6)

An edge area in which motion of the input image is generated is detected and overdrived data of the area is separated into odd frame data and odd frame data to be added to each other and the result is added to either one of the odd frame data or odd frame data A timing controller for allocating black data and overflow data to pixels of an edge area of the remaining frame data; A gate driver for outputting a gate signal to each gate line of the liquid crystal panel in response to a gate signal control signal supplied from the timing controller; And a data driver for outputting pixel signals corresponding to the data processed in the timing controller to respective data lines of the liquid crystal panel. 2. The liquid crystal display according to claim 1, wherein the timing controller is configured to alternately select one of the odd frame data or the odd frame data and to assign the resultant value to the pixels of the edge area. Device. The apparatus of claim 1, wherein the timing controller An overdriving unit for overdriving the input data using a lookup table to improve the response speed; A field memory for storing data of a previous field; A motion and edge detecting unit for detecting a motion speed and a pattern of adjacent inter-frame inter-frame images based on the data stored in the field memory and the data of the currently input field, and detecting the edge portion and outputting the detected edge portion to the data modulating unit; ; Driving frame data and odd-numbered frame data, wherein the overdriving unit separates the data of the edge area in which the motion has been generated into the odd frame data and the odd frame data, adds the results to each other, And a data modulation section for assigning the data to the corresponding pixel. The data modulator according to claim 3, wherein the data modulator is configured to allocate black data or overflow data to corresponding pixels of one frame data out of the above-mentioned excellent frame data or odd frame data, And the response time of the liquid crystal display device is improved. 4. The apparatus according to claim 3, wherein the motion and edge detecting unit sets the size of an edge portion of the image according to a motion speed of the image by the following equation.  S =? * V (mm / sec) Where V is the moving speed of the screen, S is the size of the edge of the image, and α is the proportional constant Converting data of an input image into data for overdriving; Detecting an edge region in which motion is generated in an input image; The overdrived data of the edge area in which the motion is detected is divided into the even frame data and the odd frame data and added to each other, and the result is assigned to the corresponding pixel of the frame data of the odd frame data or the odd frame data, And allocating black data or overflow data to the corresponding pixel of the frame data.

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