KR20070033823A - Data conversion unit, liquid crystal display device and driving method thereof - Google Patents

Abstract

A data conversion unit, a liquid crystal display device, and a driving method thereof that can improve image quality are disclosed.

According to an exemplary embodiment of the present invention, a liquid crystal display device determines whether a moving picture is determined using boundary data of R, G, and B data, and displays data modulated by the data conversion unit and data conversion unit performing data modulation according to the determination result. It includes a liquid crystal panel.

High speed drive, R, G, B data, frame

Description

Data conversion unit, liquid crystal display device and driving method thereof {Data conversion unit, liquid crystal display device and method for driving the same}

1 is a view showing a liquid crystal display device driven by an ODC method.

2 is a view showing a liquid crystal display device according to the present invention.

3 is a view illustrating in detail the data converter of FIG. 2;

4 is a diagram illustrating a data conversion procedure of the liquid crystal display of FIG. 2.

<Brief description of the main parts of the drawing>

102: liquid crystal panel 104: gate driver

106: data driver 108: timing controller

110: data conversion section 111: data separation section

112: system 113: frame memory

115: comparator 117: data selection unit

119: boundary surface data memory 121: multi-area data memory

123: first lookup table 125: second lookup table

127: data calculation unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data conversion, and more particularly, to a data conversion unit, a liquid crystal display device, and a driving method thereof capable of high speed driving according to characteristics of an image.

In general, a liquid crystal display device (hereinafter referred to as "LCD") is a plurality of pixels arranged in a matrix form and a plurality of control switches for controlling a video signal to be supplied to each of the pixels, that is, a thin film. In the liquid crystal panel composed of transistors (TFTs), the amount of light supplied from the backlight unit is adjusted to display a desired image on the screen.

In recent years, the liquid crystal display device is used for a monitor of a television or a computer, and in addition to a reduction in volume, the brightness of the screen in the monitor changes, that is, brightness and saturation, depending on the brightness and saturation of the surrounding environment in the monitor itself. This led to the art of controlling.

The liquid crystal display is divided into a liquid crystal panel and a driving unit for driving the liquid crystal panel. The liquid crystal panel is composed of two glass substrates (not shown), and the liquid crystal is filled between the two glass substrates. In the case of the liquid crystal display device, a syringe screen (frame) of one screen is about 16.67 ms. Meanwhile, the response speed of the liquid crystal filled in the liquid crystal display is about several tens of msec.

The light transmission characteristic of the backlight passing through the liquid crystal is determined according to the response speed of the liquid crystal. Since the response speed of the liquid crystal is slow, when the moving image is displayed on the liquid crystal display, the liquid crystal response cannot follow the change of the data voltage, and thus an afterimage occurs.

Therefore, when a moving object is rapidly displayed on the liquid crystal panel due to the slow response speed of the liquid crystal, an unwanted gray scale, ie, an afterimage or the like is displayed at the boundary of the object in the direction in which the object moves, resulting in deterioration in image quality. Is generated.

In order to solve such a slow response speed of the liquid crystal display device to drive a high speed, the ODC (Over Driving Circuit) driving method, that is, a high speed driving method has been proposed.

1 illustrates a liquid crystal display device driven by an ODC method.

As shown in FIG. 1, the liquid crystal display includes a liquid crystal panel 2 in which a plurality of gate lines GL0 to GLn and data lines DL1 to DLm are arranged to display a predetermined image, and the liquid crystal panel ( A gate driver 4 for driving the gate lines GL0 to GLn of 2), a data driver 6 for driving the data lines DL1 to DLm of the liquid crystal panel 2, and the gate driver 4 And a timing controller 8 for controlling the data driver 6, a frame memory 12 for storing the R, G, and B data of the previous frame, and a lookup table 10 for modulating the data.

A detailed description of the liquid crystal display device driven by the ODC method is well known, and thus a detailed description thereof will be omitted.

The data driver 6 receives the R, G, B data modulated by the lookup table 10 and responds to the data control signal supplied from the timing controller 8 with the modulated R, G, B data. To be supplied to the data lines DL1 to DLm.

The timing controller 8 receives the modulation data selected by the lookup table 10 and supplies the modulation data to the data driver 6.

A system, not shown, supplies R, G, B data signals to the frame memory 12 and the lookup table 10 simultaneously.

The frame memory 12 stores R, G, and B data signals supplied from a system (not shown) in units of frames. The R, G, and B data signals supplied to the frame memory 12 are temporarily stored for one frame period and then supplied to the lookup table 10 in the next frame.

The lookup table 10 receives the R, G, B data signals of the current frame supplied from the system and the R, G, B data signals of the previous frame temporarily stored in the frame memory 12 and supplied. Modulation data corresponding to the R, G, B data signals of the current frame and the R, G, B data signals of the previous frame is supplied to the timing controller 8.

In the lookup table 10, modulation data corresponding to the R, G, B data signals of the current frame and the R, G, B data signals of the previous frame are mapped in a table form.

That is, the lookup table 10 includes modulation data larger than the R, G, and B data signals of the current frame when the R, G, and B data signals of the current frame are larger than the R, G, and B data signals of the previous frame. Is set. In addition, the lookup table 10 includes modulation data smaller than the R, G, and B data signals of the current frame when the R, G, and B data signals of the current frame are smaller than the R, G, and B data signals of the previous frame. Is set.

Accordingly, the lookup table 10 outputs the modulation data corresponding to the difference value between the R, G, and B data signals of the previous frame and the R, G, and B data signals of the current frame to the timing controller 8. Supply.

The liquid crystal display device driven as described above modulates the input R, G, and B data signals to apply the modulated R, G, and B data signals to the liquid crystal to obtain desired luminance.

A liquid crystal display using a high-speed driving method compensates for the late response speed of liquid crystals by modulating the data voltage value so as to reduce an afterimage such as motion blurring in a moving image, thereby displaying an image with a desired color and luminance. do.

In other words, the high-speed driving method compares the R, G, B data signals of the previous frame with the R, G, B data signals of the current frame, and compares the R, G, B data signals of the previous frame with R, G, If there is a change between the B data signals, the corresponding modulation data is selected and modulated in the lookup table 10.

On the other hand, when a moving image of a circle is displayed on the liquid crystal panel of the liquid crystal display device driven at a high speed as described above, afterimages occur in a direction in which the circle moves at the boundary of the circle. This occurs because the data voltage representing the circle is faster than the response speed of the liquid crystal.

 Therefore, when a moving video is displayed on the liquid crystal panel rapidly due to the slow response speed of the liquid crystal, an unwanted gray scale, ie, an afterimage or the like, is displayed at the boundary of the object in the direction in which the object moves so that the image quality deteriorates. Is generated.

According to the present invention, when a moving picture such as an object moving is displayed on a liquid crystal panel in consideration of a slow liquid crystal response speed, a data conversion unit and liquid crystal capable of improving image quality by overcoming an afterimage by emphasizing the contrast of the boundary of the object. It is an object of the present invention to provide a display device and a driving method thereof.

The liquid crystal display according to the present invention for achieving the above object is a data conversion unit and the data conversion unit to determine whether the video using the boundary data of the R, G, B data, and perform data modulation according to the determination result And a liquid crystal panel for displaying the data modulated from.

According to an aspect of the present invention, there is provided a method of driving a liquid crystal display device, the method comprising: separating R, G, and B data into boundary data and data of a plurality of regions; Supplying interface data, comparing interface data of a current frame with interface data of a previous frame, modulating the interface data and data of the plurality of regions according to the comparison result, and modulating the interface data. And displaying the modulated multi-region data.

A data conversion unit according to the present invention for achieving the above object is a data separation unit for separating the R, G, B data into boundary data and data of a plurality of areas, delaying the boundary data for one frame period of the previous frame A frame memory for supplying interface data, a comparator for comparing the interface data of the current frame and the interface data of the previous frame, and first and second lookup tables for modulating the interface data and the data of the plurality of regions according to the comparison result. Include.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention.

2 is a view showing a liquid crystal display device according to the present invention.

As shown in FIG. 2, the liquid crystal display device of the present invention includes a liquid crystal panel 102 in which a plurality of gate lines GL0 to GLn and data lines DL1 to DLm are arranged to display a predetermined image. A gate driver 104 and a data driver 106 for driving the liquid crystal panel 102, a timing controller 108 for controlling the gate driver 104 and a data driver 106, and R, G, and B data. A system 112 for supplying and a data converter 110 for receiving the R, G, B data from the system 112 and outputs the modulated R ', G', B 'data.

In the liquid crystal panel 102, a plurality of gate lines GL0 to GLn and data lines DL1 to DLm are arranged, and a thin film transistor TFT which is a switching element is formed at an intersection thereof. In addition, the liquid crystal panel 102 includes two glass substrates (not shown) and a liquid crystal (not shown) filled between the glass substrates.

The gate driver 104 supplies a scan signal, that is, a gate high voltage VGH, to the gate lines GL0 to GLn according to the gate control signal generated from the timing controller 108. When the gate high voltage VGH is supplied to the gate lines GL0 to GLn, the thin film transistor TFT connected to the gate lines GL0 to GLn is turned on.

The data driver 106 supplies a data voltage to the data lines DL1 to DLm according to a data control signal generated from the timing controller 108.

The timing controller 108 receives the vertical / horizontal synchronization signal (Vsync / Hsync) and the data enable (DE) signal from the system 112 to control the gate driver 104 and the data driver 106. A gate control signal and a data control signal are generated.

The system 112 supplies R, G, and B data to the data converter 110 in units of frames.

The data converter 110 receives R, G, and B data from the system 112 and converts the R, G, and B data. As illustrated in FIG. 3, the data converter 110 divides the R, G, and B data supplied from the system 112 into boundary data and data of a plurality of regions except the boundary data. 111 and a comparator 115 for comparing the frame memory 113 temporarily storing the boundary data with the current boundary data output from the data separator 111 and previous boundary data output from the frame memory 113. ) And a data selector 117 for selecting data according to the signal output from the comparator 115.

In addition, the data converter 110 may output the first and second lookup tables 123 and 125 to which the modulated data is mapped in the form of a table, and the first and second lookup tables 123 and 125. The apparatus may further include a data calculator 127 for calculating and processing the modulated data.

The data separator 111 separates R, G, and B data supplied from the system 112 into boundary data and multi-region data. In this case, the R, G, and B data are supplied to the data separator 111 in units of one frame. Interface data of one frame separated by the data separator 111 is supplied to the frame memory 113, the comparator 115, and the data selector 117.

In addition, data of a plurality of regions separated by the data separator 111 is supplied to the data selector 117.

The frame memory 113 temporarily stores the interface data and supplies the interfacial data to the comparator 115.

The comparator 115 receives the boundary data of the current frame from the data separator 111 and the boundary data of the previous frame from the frame memory 113. In addition, the comparator 115 compares the boundary data of the current frame and the boundary data of the previous frame, outputs a control signal according to the comparison result, and supplies the control signal to the data selector 117.

The output of the low signal from the comparator 115 means that the R, G, and B data of the previous frame and the current frame R, G, and B data are the same, and the still image on the liquid crystal panel 102 It is being displayed.

The output of the high signal from the comparator 115 means that the previous frame R, G, and B data and the current frame R, G, and B data are different from each other, and a video is displayed on the liquid crystal panel 102. It means that there is.

The comparator 115 generates a low signal if there is no difference between the boundary data of the current frame and the boundary data of the previous frame, and generates a high signal if the difference exists. The low or high signal generated by the comparator 115 is supplied to the data selector 117.

The data selector 117 selects interface data and multi-region data according to a signal supplied from the comparator 115. The data selector 117 includes a boundary data memory 119 in which boundary surface data of the current frame supplied from the data separator 111 is stored, and a plurality of areas except the boundary surface data of the current frame from the system 112. And a multi-region data memory 121 in which data is stored.

When a low signal is supplied from the comparator 115 to the data selector 117, the data selector 117 selects the multi-region data memory 121 in which the multi-region data is stored and the The multi-region data is supplied to the data operation unit 127. At the same time, interface data stored in the interface data memory 119 is also supplied to the data operation unit 127.

Since the low signal is supplied from the comparator 115 to display a still image, as described above, the boundary data and the multi-region data are supplied to the first and second lookup tables 123 and 125. Is supplied to the data calculating section 127 instead. The data operation unit 127 outputs R, G, and B data by adding the boundary data and the multi-region data.

The R, G, B data is identical to the original R, G, B data supplied from the system 112. R, G, and B data output from the data calculator 127 are supplied to the timing controller 108.

The timing controller 108 arranges the R, G, and B data and supplies the data to the data driver 106. The data driver 106 converts the R, G, and B data into an analog voltage to convert the R, G, and B data into an analog voltage. DL1 ~ DLm).

On the other hand, when a high signal is supplied from the comparator 115 to the data selector 117, the data selector 117 transmits the interface data stored in the interface data memory 119 to the first data. Supply to lookup table 123. At the same time, the data selector 117 supplies the multi-region data stored in the multi-region data memory 121 to the second lookup table 125.

The first lookup table 123 receives interface data of a current frame from the interface data memory 119 and outputs modulation data corresponding to the interface data.

In addition, the second lookup table 125 receives multi-region data excluding boundary data of a current frame from the multi-region data memory 119 and outputs modulation data corresponding to the multi-region data.

The modulation interface data and the multi-region data output from the first and second lookup tables 123 and 125 are supplied to the data operation unit 127.

The data operator 127 outputs the modulated R ', G', and B 'data by adding the modulated interface data and the multi-region data and supplies the modulated R', G ', and B' data to the timing controller 108. In this case, the modulated R ', G', B 'data is different from the R, G, B data supplied from the system 112. The modulated R ', G', and B 'data is data with a higher contrast than the R, G, and B data supplied from the system 112.

The modulated R ', G', B 'data is supplied to the timing controller 108, and the timing controller 108 aligns the R', G ', B' data to the data driver 106. do. The data driver 106 supplies the R ', G', and B 'data to the data lines DL1 to DLm to be displayed on the liquid crystal panel 102.

That is, the R, G, and B data supplied from the system 112 are converted into boundary data with contrasts highlighted and multi-area data excluding the boundary data through the data converter 110.

When a circle moving to the right on the liquid crystal panel 102 is represented, the right boundary of the circle is highlighted. As a result, the dark portion of the boundary of the circle is darker and the brighter portion is brighter, resulting in a visual reduction of afterimages and the like caused by the slow response of the liquid crystal.

In the conventional liquid crystal display, when a circle moving to the right is represented, an afterimage occurs in the right part of the circle. This is because the data voltage corresponding to the circle cannot be followed due to the slow response characteristic of the liquid crystal.

Accordingly, in order to visually reduce the afterimage, the liquid crystal display according to the present invention does not change the response speed of the liquid crystal, and contrast between the boundary surface of the R, G, and B data corresponding to the data voltage and the frame data except the boundary surface Emphasize contrast.

4 is a diagram illustrating a data conversion procedure of the liquid crystal display of FIG. 2.

2 and 4, when R, G, and B data are input from the system 112, the R, G, and B data are separated into boundary data and multi-region data except for the boundary data. In particular, the boundary data of the R, G, and B data is temporarily stored using a frame memory.

Subsequently, the interface data of the R, G, and B data of the current frame is compared with the interface data of the R, G, and B data of the previous frame stored in the multi-region memory. According to the comparison result, it can be divided into two cases.

The first case 1 is a case where the boundary data of the previous frame and the boundary data of the current frame are the same, and the rest case 2 is a case where the boundary data of the previous frame and the boundary data of the current frame are different.

In case 1, the R, G, and B data supplied from the system 112 are output as it is and supplied to the timing controller 108. Accordingly, the liquid crystal panel 102 displays R, G, and B data supplied from the system 112.

In case 2, the interface data among the R, G, and B data supplied from the system 112 is converted into modulation interface data stored in the first lookup table (123 in FIG. 3). The multi-region data of the R, G, and B data is converted into modulated multi-region data stored in the second lookup table (125 in FIG. 3).

As a result, the R, G, and B data supplied from the system 112 are converted into modulated R ', G', and B 'data, which is a sum of modulated interface data and modulated multi-region data, and supplied to the timing controller 108. do.

Accordingly, R, G, and B 'data modulated by the data converter 110 are displayed on the liquid crystal panel 102 instead of R, G, and B data supplied from the system 112.

As mentioned above, the liquid crystal display according to the present invention separates R, G, and B data, which are judged as moving images, into multi-area data excluding boundary data and boundary data, and contrasts the contrast between the boundary data and the multi-area data. It is possible to visually reduce an afterimage generated in a conventional liquid crystal display by converting the data into the highlighted R ', G' and B 'data signals, thereby overcoming the afterimage and improving image quality.

As described above, the liquid crystal display according to the present invention separates the R, G, and B data supplied from the system into the boundary data and the multi-region data except for the boundary data, and uses the lookup table. The data conversion unit converts the R ', G', and B 'data signals that emphasize the contrast between the boundary data and the multi-region data to visually reduce afterimages generated in a conventional liquid crystal display, thereby improving image quality. Can be.

Claims (8)

A data converter configured to determine whether a video is generated using boundary data of R, G, and B data, and perform data modulation according to the determination result; And And a liquid crystal panel for displaying data modulated by the data converter. The method of claim 1, The data converter, A data separator for separating the R, G, and B data into boundary data and data of a plurality of regions; A frame memory for delaying the boundary data for one frame period to supply boundary data of a previous frame; A comparator for comparing the boundary data of the current frame with the boundary data of the previous frame; And And first and second lookup tables configured to modulate the boundary data and the data of the plurality of regions according to the comparison result. The method of claim 2, And a still image is displayed when the boundary data of the previous frame and the boundary data of the current frame are the same. The method of claim 2, And a video is displayed when the boundary data of the previous frame and the boundary data of the current frame are different. The method of claim 2, And a modulated boundary surface data is mapped to the first lookup table in a table form. The method of claim 2, And a plurality of modulated multi-region data are mapped to the second lookup table in a table form. Separating R, G, and B data into boundary data and data of multiple regions; Supplying interface data of a previous frame by delaying the interface data for one frame period; Comparing the boundary data of the current frame with the boundary data of the previous frame; Modulating the boundary data and the data of the plurality of regions according to the comparison result; And And displaying the modulated interface data and the modulated multi-region data. A data separator for separating the R, G, and B data into boundary data and data of a plurality of regions; A frame memory for delaying the boundary data for one frame period to supply boundary data of a previous frame; A comparison unit comparing the boundary data of the current frame with the boundary data of the previous frame; And And a first and a second lookup table for modulating the boundary data and the data of the plurality of regions, respectively, according to the comparison result.

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