KR100707021B1 - Liquid Cristal Display Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a plurality of thin film transistors arranged in a matrix form at a cross region of a plurality of gate lines, a plurality of data lines, a plurality of gate lines and a plurality of data lines, A lower substrate having a plurality of pixel electrodes electrically coupled to the thin film transistor; An upper substrate receiving a common voltage and having a counter electrode disposed to face the pixel electrode, wherein the upper substrate is bonded to the lower substrate; A plurality of gate driver integrated circuits outputting scan signals to the plurality of gate lines; A plurality of data driver integrated circuits for outputting data signals to the plurality of data lines; And a single transfer disposed in an area where the rear end of the gate line and the upper end of the data line cross each other and are electrically coupled to the counter electrode to apply a common voltage to the counter electrode.

Description

Liquid Crystal Display Device

1 is a cross-sectional view showing a panel structure of a liquid crystal display device according to the prior art.

2 is a perspective view illustrating a panel structure of a liquid crystal display according to the related art.

3A and 3B are diagrams for explaining a transfer configuration of a liquid crystal display device according to the prior art.

4 is a timing diagram showing the voltage waveform of the gate line in the liquid crystal display according to the prior art.

5 is a timing diagram showing voltage waveforms of data lines in the liquid crystal display according to the related art.

6 is a cross-sectional view illustrating a panel structure of a liquid crystal display according to an exemplary embodiment of the present invention.

7 is a view for explaining a liquid crystal display device according to an embodiment of the present invention;

8 is a view for explaining a test method of a liquid crystal display according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of efficiently applying a common voltage to a counter electrode in a liquid crystal table market value of a dot inversion driving method.

In general, the liquid crystal display adopting the line inversion driving method uses an alternating voltage as a common voltage, and cross-talk or wave occurs on the display due to distortion and interference due to various influences, resulting in a deterioration of screen quality. Problem occurs. In order to prevent such a problem, a liquid crystal display device having a line inversion driving method and a dot inversion driving method uses a plurality of transfers to stably supply a common voltage to a counter electrode of an upper substrate.

FIG. 1 is a cross-sectional view illustrating a panel structure of a dot inversion driving type liquid crystal display device according to the related art, and as shown in FIG. 1, is spaced apart from each other by a predetermined interval through a liquid crystal 1 to face a sealing material 2. And a lower substrate 4 and an upper substrate 6 bonded together.

A plurality of pixel electrodes 8 and an alignment layer 10 are formed on the lower substrate 4, and a polarizing plate 12 is formed below the lower substrate 4. The plurality of pixel electrodes 8 are formed of a transparent and conductive indium thin oxide (ITO) material. A plurality of color filters 14, a black matrix (not shown), a counter electrode 16, and an alignment layer 18 are formed below the upper substrate 6, and above the upper substrate 6. The polarizing plate 20 is formed. The counter electrode 16 is formed of an indium thin oxide (ITO) material that is transparent and conductive. A plurality of spacers 22 are distributed between the alignment layers 10 and 18 to maintain a constant gap. Transfers 24 and 24 electrically connecting the common voltage line formed on the lower substrate 4 and the counter electrode 16 formed on the upper substrate 6 to the inside of the encapsulant 2. ') Is formed.

The conventional liquid crystal display configured as described above is driven according to an electric field generated by a voltage difference between the common voltage applied to the counter electrode 16 and the positive and negative data voltages applied to the data line (not shown). .

FIG. 2 is a perspective view showing a panel structure of a dot inversion driving type liquid crystal display device according to the related art, in which the same reference numerals are used for the same parts as those of FIG. In the figure, reference numeral 26 denotes a printed circuit board (PCB), 28 denotes a driver integrated circuit (Drive IC), and 30 denotes a common voltage line.

In the liquid crystal display according to the related art, as shown in FIG. 2, the common voltage generated from the common voltage generating circuit of the printed circuit board 26 is applied to the plurality of common voltage lines 30 through the driver integrated circuit. The common voltage applied to the common voltage line 30 is configured to be applied to the counter electrode of the upper substrate 6 through the plurality of transfers 24 and 24 '.

The plurality of common voltage lines 30 are electrically connected to the plurality of transfers 24 and 24 'provided on the lower substrate 4 to form a plurality of common voltage application paths.

3A and 3B are diagrams for describing a transfer configuration of a dot inversion driving type liquid crystal display device according to the related art. Reference numeral 100 denotes a liquid crystal panel, 102 denotes a gate driver printed circuit board, 104 denotes a gate driver integrated circuit, 106 denotes a data driver printed circuit board, 108 denotes a data driver integrated circuit, and 110 denotes a flexible printed circuit board. Flexible Printed Circuit (hereinafter referred to as FPC) and 112 and 114 represent transfers, respectively.

Referring to FIG. 3A, the plurality of transfers 112 are provided to face the left and right edges in the central region of the liquid crystal panel 100.

Referring to FIG. 3B, the plurality of transfers 114 are provided to face upper and lower edges in the central region of the liquid crystal panel 100.

FIG. 4 is a timing diagram illustrating a voltage waveform at the front end of a gate line and a voltage waveform at the rear end of a gate line in the liquid crystal display according to the related art. FIG. 5 is a voltage diagram of the data line front end in the liquid crystal display according to the prior art. A timing diagram showing a waveform and a voltage waveform at the rear end of a data line. Here, reference numeral Vgate denotes a voltage applied to the gate line, Vd + denotes a positive data voltage, Vd− denotes a negative data voltage, Vp + denotes a positive pixel charge voltage, and Vp− denotes a negative pixel charge voltage, Vcom_l represents a left common voltage to minimize flicker, Vcom_r represents a right common voltage to minimize flicker, Vcom_u represents an upper common voltage to minimize flicker, and Vcom_d represents a lower common voltage to minimize flicker.

In the LCD according to the related art, as shown in FIGS. 4 and 5, the voltage drop is proportional to the length of the line from the front end to the rear end of the data line and the gate line by the gate line voltage delay and the data line voltage delay. Is generated, and as a result, the timing diagrams of Figs. 4 and 5 are obtained.

The liquid crystal display according to the related art, which is configured as described above, has a method of applying a common voltage using a plurality of transfers.

First, the printed circuit board pattern design becomes complicated.

Second, when designing a liquid crystal panel, it is difficult to arrange a large number of transfers for low resistance and to design a thick pattern.

Third, the manufacturing cost increases due to an increase in the manufacturing process of the liquid crystal panel and an increase in tact time.

Fourth, the recently developed module of the liquid crystal display device has no gate printed circuit board, and the common voltage applied to the existing FPC and gate printed circuit board is applied to the lower substrate along with the signals necessary for driving the gate driver integrated circuit. Because the formed pattern must be used, many spatial constraints are generated in the design of the liquid crystal panel.

Fifth, flicker occurs due to the delay of the gate and the data line due to the voltage drop.

Accordingly, an object of the present invention is to provide a liquid crystal display capable of reducing flicker by applying a common voltage to a counter electrode through a single common voltage application path in a liquid crystal display device employing a dot inversion driving method to solve the above problems. To provide a device.

A liquid crystal display according to the present invention for achieving the above object is a plurality of thin film transistors arranged in a matrix form at the intersection of the plurality of gate lines, the plurality of data lines, the plurality of gate lines and the plurality of data lines. A lower substrate having a plurality of pixel electrodes electrically coupled to the plurality of thin film transistors; An upper substrate receiving a common voltage and having a counter electrode disposed to face the pixel electrode, wherein the upper substrate is bonded to the lower substrate; A plurality of gate driver integrated circuits outputting scan signals to the plurality of gate lines; A plurality of data driver integrated circuits for outputting data signals to the plurality of data lines; And a single transfer disposed in an area where a rear end of the gate line and an upper end of the data line cross each other and are electrically coupled to the counter electrode to apply the common voltage to the counter electrode.

(Example)

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

FIG. 6 is a cross-sectional view illustrating a panel structure of a liquid crystal display according to an exemplary embodiment of the present invention. As shown in FIG. 6, a panel structure of the liquid crystal display according to an embodiment of the present invention is spaced apart from each other by a predetermined interval through the liquid crystal 200. And a lower substrate 204 and an upper substrate 206 that are joined by each other.

A plurality of pixel electrodes 208 and an alignment layer 210 are formed on the lower substrate 204, and a polarizer 210 is formed below the lower substrate 204. The plurality of pixel electrodes 208 are formed of a transparent and conductive indium thin oxide (ITO) material.

A plurality of color filters 14, a black matrix (not shown), a counter electrode 216, and an alignment layer 218 are formed below the upper substrate 206, and above the upper substrate 206. The polarizer 220 is formed. The counter electrode 216 is formed of a transparent and conductive indium thin oxide (ITO) material. A plurality of spacers 222 are distributed between the alignment layers 210 and 218 to maintain a constant gap. A single transfer is formed inside the encapsulation material 2 to electrically connect the pixel electrode 8 formed on the lower substrate 4 and the counter electrode 16 formed on the upper substrate 6. 224 is formed.

The liquid crystal display according to the present invention configured as described above is driven in accordance with an electric field generated by a voltage difference between a common voltage applied to the counter electrode 216 and a positive and negative data voltage applied to a data line (not shown). do.

FIG. 7 is a view for explaining a liquid crystal display device according to an exemplary embodiment of the present invention. As illustrated, the liquid crystal panel 300, the gate driver printed circuit board 310, and the data driver printed circuit board 320 are illustrated. ), A plurality of gate driver integrated circuits 330, a plurality of data driver integrated circuits 340, and a flexible printed circuit board (FPC) 350.

The lower substrate of the liquid crystal panel 300 has a plurality of gate lines GL, a plurality of data lines DL, and a plurality of gate lines DL and a plurality of data lines DL arranged in a matrix. The plurality of thin film transistors ST and the plurality of pixel electrodes PE electrically connected to the plurality of thin film transistors ST are formed.

In addition, a single transfer 360 is installed on a lower substrate of the liquid crystal panel 300 in an area where the rear ends of the plurality of gate lines GL and the upper ends of the data lines DL intersect. The single transfer 360 is electrically coupled to the counter electrode and configured to transfer a common voltage generated by a common voltage generator (not shown) and applied to the common voltage line to the counter electrode.

Between the gate driver printed circuit board 310 and the lower substrate of the liquid crystal panel 300, a plurality of gate driver integrated circuits 340 for outputting scan signals to the plurality of gate lines may include a tape carrier package (TCP: Tape Carrier Pakage, (Not shown). Between the data driver printed circuit board 320 and the lower substrate of the liquid crystal panel 300, a plurality of data driver integrated circuits 330 for outputting data signals to the plurality of data lines may include a tape carrier package (TCP). (Not shown).

When the single transfer 360 is installed in the liquid crystal panel 300 according to the preferred embodiment of the present invention, as shown in FIG. 7, an equivalent circuit 370 is formed.

8 is a view for explaining a test method of a liquid crystal display according to an exemplary embodiment of the present invention. In the figure, reference numeral 400 denotes a liquid crystal panel, 410 a gate printed circuit board, 420 a data driver printed circuit board, 430 a plurality of gate driver integrated circuits, 440 a plurality of data driver integrated circuits, and 450 A flexible printed circuit (FPC) and 460 and 470 represent a plurality of transfers, respectively.

Referring to FIG. 8, a common voltage test method according to an exemplary embodiment of the present invention is provided with a plurality of transfers 460 and 470 capable of laser cutting along upper and lower edges in a central area of the liquid crystal panel 400. The laser lines are sequentially cut from the front end of the gate line, i.e., the gate printed circuit board, to the rear end of the gate line, and the common voltage is applied through the gate driver integrated circuit at the front end of the plurality of gate driver integrated circuits. Measure incidence.

9 is a diagram illustrating a common voltage test result of a liquid crystal display according to an exemplary embodiment of the present invention. In the same figure, reference numeral a denotes that the laser cutting is not performed at all, b denotes the laser cut of the transfer of the portion A, c denotes the laser cut of the transfer to the portion B, and d denotes the laser cut of the transfer to the portion C. It is a graph showing the result of measuring flicker incidence in the case.

According to an embodiment of the present invention, when the laser cut is performed to the portion C, an improvement of 1 dB or more can be obtained in terms of flicker compared to the case where the laser cutting is not performed at all.

According to another embodiment of the present invention, when there is no gate printed circuit board when a signal is applied to the gate driver integrated circuit, it is preferable not to form a common voltage line on the lower substrate.

While specific embodiments of the present invention have been described and illustrated above, it will be apparent that the present invention may be modified and practiced by those skilled in the art. Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, but should fall within the claims appended to the present invention.

 As described above, the present invention eliminates a plurality of transfer and common voltage lines in the liquid crystal display device employing the dot inversion driving method and applies flicker generation to the counter electrode through a single common voltage application path. In addition to reducing, the design of the liquid crystal panel can be simplified and facilitated.

In addition, the present invention has another effect that the design of the printed circuit board is easy due to the reduction of the common voltage line.

In addition, since the present invention can remove the common voltage connection line of the gate printed circuit board, there is another effect that the connector selection and FPC design is facilitated due to the reduction of the connector pin and the FPC line.

In addition, when the present invention is applied to a liquid crystal display device without a gate printed circuit board, the liquid crystal panel can be easily designed when the signal wiring applied to the gate driver integrated circuit is designed on the panel.

Claims (3)

A plurality of thin film transistors arranged in a matrix form in a plurality of gate lines, a plurality of data lines, an intersection of the plurality of gate lines and the plurality of data lines, and a plurality of electrically coupled to the plurality of thin film transistors. A lower substrate having a pixel electrode; An upper substrate receiving a common voltage and having a counter electrode disposed to face the pixel electrode, wherein the upper substrate is bonded to the lower substrate; A plurality of gate driver integrated circuits outputting scan signals to the plurality of gate lines; A plurality of data driver integrated circuits for outputting data signals to the plurality of data lines; And And a single transfer device disposed in an area of the lower substrate where a rear end of the gate line and an upper end of the data line intersect and are electrically coupled to the counter electrode to apply the common voltage to the counter electrode. A liquid crystal display device. The method of claim 1, And wherein the common voltage is applied to the transfer through a gate driver integrated circuit at a leading end of the plurality of gate driver integrated circuits. The method of claim 1, And a common voltage line is not formed on the lower substrate when there is no gate printed circuit board when the signal is applied to the gate driver integrated circuit.

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