KR101108296B1 - Iquid crystal display device and driving method using the same - Google Patents

Abstract

The present invention relates to a liquid crystal display and a driving method thereof.

According to an exemplary embodiment of the present invention, a liquid crystal display includes a first liquid crystal panel having a first gate line and a first data line, and a second data line in which some of the second gate line and the first data line of the first liquid crystal panel are shared. The second liquid crystal panel has a second liquid crystal panel, a conductive film electrically connecting the first and second data lines, and a size of a signal supplied to the shared data line and a signal supplied to the other data line. A data driver is provided.

Description

Liquid crystal display and its driving method {IQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD USING THE SAME}

1 is a view showing a conventional liquid crystal display device.

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

3 is a view showing in detail the liquid crystal panel of FIG.

4 is a view illustrating in detail the driving circuit of FIG. 2.

5 is a diagram illustrating each region of a liquid crystal panel according to a first embodiment of the present invention.

6A and 6B illustrate slopes of signals supplied to respective regions of FIG. 5.

7 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention.

FIG. 8 is a diagram illustrating a change in slope of a signal supplied to region “B” of FIG. 7.

9 is a diagram illustrating a liquid crystal display according to a third exemplary embodiment of the present invention.

               <Description of Symbols for Main Parts of Drawings>

2, 102, 202, 302: first liquid crystal panel

12, 112, 212, and 312: second liquid crystal panel

20, 130, 230, 330: system 21, 22, 120: drive circuit

106, 206, 306: data driver 132, 232, 332: timing controller

134, 234, 334: power supply 140: conductive film

142: gate connection signal line

208a, 208b, 208c, 308a, 308b: buffer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device and a driving method thereof capable of reducing the number of parts and improving image quality uniformity.

In general, a liquid crystal display (hereinafter referred to as "LCD") is a typical flat panel display that displays an image by adjusting an amount of light beam transmission to correspond to an image signal. In particular, LCDs are in a trend of widening their application range due to features such as light weight, thinness, and low power consumption. According to this trend, LCDs are being applied as display devices for office automation devices and notebook computers. In addition, in order to meet the demands of users, LCDs are progressing toward larger screens, higher resolutions, and lower power consumption, so that cathode ray tubes are rapidly replaced in many applications. In particular, an active matrix type liquid crystal display device that drives a liquid crystal cell using a thin film transistor (hereinafter referred to as "TFT") has the advantages of excellent image quality and low power consumption, and secures the latest mass production technology. As a result of research and development, it is rapidly developing into larger size and higher resolution.

In recent years, such liquid crystal display devices are getting more attention as display devices for portable terminals and notebook computers. In particular, by providing a stable image quality, it is out of print as a display device for dual monitor of a portable terminal.

1 is a view showing a conventional liquid crystal display device for a dual monitor.

Referring to FIG. 1, a liquid crystal display device for a dual monitor according to the related art includes a main panel 1 implementing a main image, a sub panel 11 implementing a sub image, a main panel 1, and a sub panel 11. A first driving circuit 21 and a second driving circuit 22 for generating and supplying an image data signal and a control signal for controlling the image data signal so as to implement an image in each of them; A system 20 for supplying signals to the 21 and 22 is provided. The main panel 1 implements a main image. The main panel 1 generally has a higher resolution than the sub panel 11.

A conventional liquid crystal display having a dual monitor having such a structure includes first and second driving circuits 21 and 22 to drive the first and second liquid crystal panels 2 and 12, respectively. Accordingly, the conventional liquid crystal display device having a dual monitor has limitations of thinness and simplicity of the liquid crystal display device by providing two driving circuits for two liquid crystal panels, and increases the number of parts by providing two driving circuits. There is a problem that the unit price of goods rises.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a driving method thereof which can reduce the number of parts and improve the image quality uniformity.

In order to achieve the above object, the liquid crystal display according to the present invention includes a first liquid crystal panel having a first gate line and a first data line, and a portion of the second gate line and the first data line of the first liquid crystal panel. A second liquid crystal panel having a second shared data line, a conductive film electrically connecting the first and second data lines, a magnitude of a signal supplied to the shared data line, and other data lines A data driver is provided for supplying signals of different sizes.

The data driver is characterized in that the supply of the signal supplied to the shared data line is larger than the signal supplied to the other data line.

The data driver may be configured to supply the signal supplied to the shared data line and the signal supplied to the other data line to have the same size.

The data driver includes a first data driver connected to the shared data line and a second data driver connected to other data lines, and a bias current of a buffer included in the first data driver is determined by the second data driver. The bias current of the buffer included in the data driver is set to be larger.

The data driver generates and supplies a first data driver connected to the shared data line, a second data driver connected to other data lines, and a control signal supplied to the first and second data drivers. The control unit may further include a control signal supplied to the first data driver and a control signal supplied to the second data driver.

At least one of the first and second gate lines may be a LOG type.

And a first gate driver for driving the first gate line, and a second gate driver for driving the second gate line, wherein the conductive film is configured to provide a signal supplied to the first gate driver to the second gate driver. And a gate connection signal line to supply the gate driver.

A driving method of a liquid crystal display device according to an exemplary embodiment of the present invention is a driving method of driving first and second liquid crystal panels that share a part of a data line, and includes a signal supplied to the shared data line and other data lines. Characterized in that the different size of the supplied signal.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

2 is a diagram illustrating a liquid crystal display according to a first embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display according to the first exemplary embodiment of the present invention includes a first liquid crystal panel 102 for implementing a main image, a second liquid crystal panel 112 for implementing a sub image, and a first liquid crystal. A conductive film 140 connecting the panel 102 and the second liquid crystal panel 112, a driving circuit 120 driving the first liquid crystal panel 102 and the second liquid crystal panel 112, and a driving circuit ( A system 130 for generating and supplying a signal to the signal 120.

As shown in FIG. 3, the first liquid crystal panel 102 includes a color filter array substrate 81 and a thin film transistor array substrate 91 bonded together with the liquid crystal 86 interposed therebetween.

The liquid crystal 86 is rotated in response to an electric field applied to the liquid crystal 86 to adjust the amount of light transmitted through the thin film transistor array substrate 91.

The color filter array substrate 81 includes a black matrix 96, a color filter 82, and a common electrode 84 formed on the rear surface of the upper substrate 80a. The black matrix 96 is formed of an opaque material and absorbs light incident from adjacent cells, thereby preventing a decrease in contrast. In the color filter 82, the color filter layers of red (R), green (G), and blue (B) colors are arranged in a stripe form to transmit light of a specific wavelength band, thereby enabling color display.

The thin film transistor array substrate 91 is formed such that the first data line 98 and the first gate line 94 cross each other on the front surface of the lower substrate 80b, and the TFT 90 is formed at the intersection thereof. The TFT 90 includes a gate electrode connected to the gate line 94, a source electrode connected to the first data line 98, and a drain electrode facing the source electrode with a channel interposed therebetween. The TFT 90 is connected to the pixel electrode 92 through a contact hole penetrating through the drain electrode. The TFT 90 selectively supplies the data signal from the first data line 98 to the pixel electrode 92 in response to the gate signal from the first gate line 94.

The pixel electrode 92 is positioned in a cell region divided by the first data line 98 and the first gate line 94 and is made of a transparent conductive material having high light transmittance. The pixel electrode 92 generates a potential difference from the common electrode 84 formed on the upper substrate 80a by the data signal supplied via the drain electrode. Due to this potential difference, the liquid crystal 86 located between the lower substrate 80b and the upper substrate 80a is rotated by dielectric anisotropy. Accordingly, the light supplied from the light source via the pixel electrode 92 is transmitted toward the upper substrate 80a.

The second liquid crystal panel 112 has the same configuration as that of the first liquid crystal panel 102, and the resolution of the first liquid crystal panel 102 has a resolution greater than or equal to that of the second liquid crystal panel 112. Here, the resolution of the first liquid crystal panel 102 and the resolution of the second liquid crystal panel 112 may be the same.

The driving circuit 120 for driving the first liquid crystal panel 102 and the second liquid crystal panel 102, 112 is configured to drive the first gate lines 94 of the first liquid crystal panel 102 as shown in FIG. 4. The second gate driver 114 for driving the first gate driver 104 and the second gate line 194 of the second liquid crystal panel 112, the first data line 98 and the second data line 194. Is provided with a data driver 106 for driving.

The system 130 includes a timing controller 132 for supplying control signals for controlling the first and second gate drivers 104 and 114 and the data driver 106 and a liquid crystal display according to the control of the timing controller 132. And a power supply 134 for supplying various drive voltages used in the apparatus.

The timing controller 132 controls driving timings of the first and second gate drivers 104 and 114 and the data driver 106, and supplies a pixel data signal to the data driver 106.

The power supply unit 164 generates driving voltages such as a common voltage VCOM, a gate high voltage VGH, and a gate low voltage VGL required by the liquid crystal display using the input power.

The first and second gate drivers 104 and 114 sequentially supply gate signals to the first and second gate lines 94 and 194, respectively, to form liquid crystal cells on the first and second liquid crystal panels 102 and 112. Drive them one line at a time.

The data driver 106 supplies a pixel voltage signal to each of the first and second data lines 94 and 194 whenever the gate signal is supplied to any one of the first and second gate lines 94 and 194. do. Accordingly, the liquid crystal display displays an image by adjusting light transmittance by an electric field applied between the pixel electrode and the common electrode according to the pixel voltage signal for each liquid crystal cell.

Among them, the data driver 106 directly connected to the first liquid crystal panel 102 and the first and second gate drivers 104 and 114 directly connected to the first liquid crystal panel 102 and the second liquid crystal panel 112, respectively. ) Is integrated into a plurality of integrated circuits (ICs). Each of the integrated data drive IC and the gate drive IC is mounted on a tape carrier package (TCP) and connected to a liquid crystal panel by a tape automated bonding (TAB) method or mounted on each liquid crystal panel by a chip on glass (COG) method. .

Here, the drive ICs connected to the liquid crystal panel in a TAB manner through TCP are interconnected with the control signals and DC voltages input from the outside through signal lines mounted on a printed circuit board (PCB) connected to the TCP. . In detail, the data drive ICs are connected in series through signal lines mounted on the data PCB, and also commonly receive control signals from the timing controller 132, pixel data signals, and driving voltages from the power supply unit 134. do. The gate drive ICs are connected in series through signal lines mounted on the gate PCB, and are commonly supplied with control signals from the timing controller 132 and driving voltages from the power supply unit 134.

The drive ICs mounted on the liquid crystal panel in the COG method are line on glass (hereinafter referred to as "LOG") in which signal lines are mounted on the first and second liquid crystal panels 102 and 112, that is, the lower glass. In addition, the control signals and the driving voltages from the timing controller 132 and the power supply unit 134 are supplied.

In the liquid crystal display according to the first exemplary embodiment of the present invention, even when the drive ICs are connected to the liquid crystal panel by the TAB method, the LCD may be further thinned by removing the PCB by using the LOG method. In particular, the gate PCB can be removed by forming the signal lines connected to the gate drive ICs requiring relatively few signal lines on the liquid crystal panel in a LOG method. In other words, the TAB type gate drive ICs are connected in series through signal lines mounted on the lower glass of the liquid crystal panel, and are commonly supplied with control signals and driving voltage signals.

The conductive film 140 electrically connects a portion of the first data line 98 of the first liquid crystal panel 102 and the second data line 198 of the second liquid crystal panel 112. Accordingly, some of the data signals supplied to the first data line 98 of the first liquid crystal panel 102 are equally supplied to the second data line 198 of the second liquid crystal panel 112. That is, the data signal is supplied to the second data line 198 connected to the first data line 98. In addition, the gate signals supplied to the first gate driver 104 may be equally supplied to the second gate driver 114 using the gate connection signal line 142 formed on the conductive film 140. Here, the FPC (Flexible Printed Circuit) is used for the conductive film 140.

A driving method of the liquid crystal display device according to the first embodiment of the present invention having such a structure will be described.

First, a data signal and a control signal generated from the system 130 are supplied to the data driver 106 and the first gate driver 104.

Thereafter, the data driver 106 converts the signal and supplies the signal to the first data line 98 and the second data line 198 connected to the conductive film 140. At the same time, the first gate driver 104 sequentially supplies the gate signal to the first gate line 94. Here, the first gate driver 104 transfers the gate signal to the second gate driver 114 using the gate connection signal line 142 formed on the conductive film 140. The second gate driver 114 receiving the gate signal supplies the gate signal to the second gate line 194. Here, the second gate line 194 supplied with the gate signal and the second data line 198 supplied with the data signal respectively implement images in response to the supplied signal.

In the liquid crystal display according to the first exemplary embodiment of the present invention, the first data line 98 is connected to the second data line 198 of the second liquid crystal panel 112 as shown in FIG. 5. Connected and driven. That is, as the data lines of the "B" region are driven with longer lengths than the data lines of the "A" region and the "C" region, the image lines implemented in the "A" region and the "C" region and the "B" region are The image to be implemented will represent different picture quality. Specifically, since the data line of the "B" region is formed longer than the data lines of the "A" region and the "C" region, the voltage drop of the signal supplied to the data line of the "B" region by line resistance or the like is " It becomes larger than the voltage drop of the signal supplied to the data lines in the areas A "and" B ". In addition, the signal supplied from the data driver 106 to the data lines of the "A" region and the "C" region reaches the design value from the time of supplying the signal, and is supplied with a threshold rate as shown in FIG. 6A. On the other hand, since the data line of the "B" region is formed longer than the data lines of the "A" region and the "C" region, the signal supplied from the data driver 106 to the data line of the "B" region is designed from the point of supply. It will be fed with a slope as shown in Fig. 6b to reach the value. Therefore, when the level of the signal supplied from the data driver 106 is equally supplied to the "A", "B", and "C" areas, the image of the "B" area is the "A" area and the "C" area. The problem that appears darker than the image of the will occur. In particular, when the data driver 106 is driven by applying a three multiplexing driving method of supplying signals to three data lines using one buffer, the supply time of the signals supplied to each data line is transferred. As a result, the signal supplied to the region "B" of the first liquid crystal panel 102 sharing the data line with the second liquid crystal panel 112 has a problem of reaching the design value. As a result, the data output of the target data voltage, that is, the delay time of the design value increases, resulting in an image quality unevenness. Accordingly, the liquid crystal display device according to the second embodiment of the present invention will propose a liquid crystal display device that can prevent such a problem.

7 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention.

Herein, the liquid crystal display according to the second exemplary embodiment of the present invention has the same configuration as that of the liquid crystal display according to the first exemplary embodiment of the present invention except for the data driver 206. The description of the excluded configuration will be omitted.

Referring to FIG. 7, the liquid crystal display according to the second exemplary embodiment of the present invention provides a data driver (eg, a data driver) to supply a signal generated from the system 230 to the first liquid crystal panel 202 and the second liquid crystal panel 212. 206 and first and second gate drivers 204 and 214.

The data driver 206 supplies a first data driver 206a for supplying a signal to the "A" area, a second data driver 206b for supplying a signal to the "B" area, and a signal to the "C" area. And a third data driver 206c, each driver may be integrated.

In the data driver 206 according to the second embodiment of the present invention, the second data driver 206b for supplying a signal to the data line in the "B" area provides a signal to the data lines in the "A" area and the "C" area. It drives by changing the output characteristics of a signal larger than the 1st and 3rd data drivers 206a and 206c supplied. In detail, when the uniform luminance of the first liquid crystal panel 202 is 100, and the intensity of the signal supplied by the first and third data drivers 206a and 206c is 100, the second data driver ( By setting the intensity of the signal supplied by 206b to 100 or more, the luminance displayed in the area "B" of the first liquid crystal panel 202 is displayed as 100. Here, the luminance of the "B" region can be experimentally adjusted to the output characteristics of the data driver 206b of the "B" region to have the same luminance as the "A" region and the "C" region. The output characteristics of the data driver 206b in the “B” region may be variously set according to the size of the second liquid crystal panel 212 and the characteristics of the conductive film 240.

Here, the signal output characteristic supplied to the "B" region may be adjusted by adjusting the characteristic of the buffer 208b included in the second data driver 206b. Specifically, the bias current of the "B" region buffer 208b is set to be larger than the bias current of the "A" region and the "C" region. Accordingly, as shown in FIG. 8, the time to reach the design value after the signal is supplied is reduced to 2t-> t to improve the output characteristics of the signal supplied to the data line in the "B" region. The signal output characteristic supplied to the area “B” may be adjusted by the timing controller 232 included in the system 230. That is, the signal output characteristic supplied to the data line of the "B" region can be changed by adjusting the size of the power supplied from the power supply 234 to the data driver of the "B" region under the control of the timing controller 232. .

On the other hand, the liquid crystal display according to the second embodiment of the present invention divides the area of the first liquid crystal panel 202 into three areas "A", "B", "C", and the data line of the "B" area. Although the second liquid crystal panel 212 is set to be shared, the liquid crystal display according to the third exemplary embodiment of the present invention is the first liquid crystal shared with the data line of the second liquid crystal panel 312 as shown in FIG. 9. An area of the panel 302 may be divided into an "A" area, and other areas may be divided into an "B" area. Accordingly, the data driver 306 of the liquid crystal display device according to the third embodiment of the present invention has the characteristics of the buffer 308a of the first data driver 306a which supplies a signal to the data line 398a in the "A" region. That is, by changing the bias current, the output characteristic of the signal supplied to the data line 398a in the "A" region can be adjusted. In addition, by controlling the power from the power supply unit 334 by using the timing controller 332, the output characteristic of the signal supplied to the data line in the "A" region can be adjusted.

The driving apparatus of the liquid crystal display device according to the third embodiment of the present invention outputs signals supplied to the "A" and "B" areas by adjusting the output characteristics of the signals supplied to the data lines 398b of the "B" area. The characteristics can be formed identically. That is, by setting the output characteristic of the signal supplied to the data line 398b in the "B" region low, it can be formed in the same manner as the output characteristic of the signal supplied to the data line 398a in the "A" region.

As described above, the liquid crystal display device and the driving method thereof according to the present invention reduce the number of parts by reducing the number of data drivers in a liquid crystal panel using a dual monitor, and supply to a specific region of the liquid crystal panel sharing data lines. By varying and supplying the characteristic of the signal to be supplied, the image quality can be made uniform by uniformizing the signal supplied to the liquid crystal panel as a whole.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (8)

A first liquid crystal panel having a first gate line and a first data line; A second liquid crystal panel having a second data line in which a second gate line and a part of the first data lines of the first liquid crystal panel are shared; A conductive film electrically connecting the first and second data lines; And a data driver for supplying the signal supplied to the shared data line differently from the signal supplied to the shared data line. The method of claim 1, The data driver And supplying the signal to the shared data line larger than the signal to the other data line. The method of claim 1, Since the shared data line and the other data line have different resistance values, signals having different magnitudes are supplied to the shared data line and the other data lines, thereby providing uniform signals to the entire first and second liquid crystal panels. Liquid crystal display characterized in that the supply. The method of claim 1, The data driver A first data driver connected with the shared data line, And a second data driver connected to another data line, And the bias current of the buffer included in the first data driver is set to be greater than the bias current of the buffer included in the second data driver. The method of claim 1, The data driver A first data driver connected with the shared data line, A second data driver connected to the other data line; And a timing controller configured to generate and supply control signals supplied to the first and second data drivers. And a control signal supplied to the first data driver and a control signal supplied to the second data driver are different from each other. The method of claim 1, And at least one of the first and second gate lines is of a LOG type. The method of claim 1, A first gate driver for driving the first gate line; And a second gate driver for driving the second gate line. The conductive film And a gate connection signal line to supply a signal supplied to the first gate driver to the second gate driver. In the driving method for driving the first and second liquid crystal panel that shares a part of the data line, And supplying different magnitudes of the signal supplied to the shared data line and the signal supplied to the other data line.

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