KR100403768B1 - Apparatus for removing static electricity of liquid crystal display panel - Google Patents

Abstract

PURPOSE: An apparatus for removing static electricity of a liquid crystal display panel is provided to prevent insulation destruction caused by static electricity. CONSTITUTION: A plurality of shift registers(110), a gate driving circuit(120) and a display cell array having a plurality of thin film transistors are formed on a glass panel(100). The first and second power supply voltages(VDD,VSS) supplied to the gate driving circuit are connected to a shorting line(170) connected to a data line(160). The gate driving circuit includes gate driving switching elements, and an N channel switching element, and a P channel switching element which are serially connected to the gate driving switching elements. The input ports and output ports of the N channel and P channel switching elements are connected to a gate line(150). The drain electrode of the N channel switching element is connected to the first power supply voltage at a high level, and the drain electrode of the P channel switching element is connected to the second power supply voltage at a low level. The potential of the gate line is lower than or identical to the first power supply voltage and higher than or identical to the second power supply voltage in normal state.

Description

Static eliminator of liquid crystal panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel, and in particular, to prevent the switching device from being destroyed due to static electricity generated due to the potential difference between the switching device for switching the data line and the display cell array during the manufacturing process of the liquid crystal panel. It relates to a static electricity removing device of the liquid crystal panel for.

In general, an active matrix (AM) liquid crystal display device using a polysilicon thin film transistor (poly Si TFT) uses a high charge mobility characteristic of a polysilicon thin film transistor, as shown in FIG. (10), a gate driver circuit 12 for driving an image signal, a data driver circuit 20, and a plurality of thin film transistors 14 are fabricated on the transparent glass substrate 1 together.

Here, in order to electrically separate the gate line 16 and the data line 18, a gate insulating film such as SiNx is formed on the entire surface of the glass substrate 1 using a chemical vapor deposition (PECVD) method.

At this time, the static electricity generated in the process of manufacturing the display cell array 14 made of the polysilicon thin film transistor and the liquid crystal injection process on the insulating substrate generates a fatal gate insulation breakdown according to the surrounding environment or the substrate moving state.

That is, when the electrostatic discharge is generated at the relatively incomplete or thin insulating region between the gate line 16 and the data line 18, a short circuit occurs between the two lines 16 and 18, which is a fatal defect in the liquid crystal display. .

In order to solve such a defect, a short circuit 25 is formed in the data line 16 and the gate line 18 as shown in FIG. 2A.

As a result, even when static electricity is generated during the process of the display cell array 14, the potential between the gate line 16 and the data line 18 is the same, thereby preventing the breakdown between the electrodes during the process.

When there is no short circuit line 25, when static electricity is generated at the gate electrode 16, as shown in FIG. 3, there is no current path through which the electrostatic charge can be released, resulting in insulation breakdown of the gate line.

Meanwhile, when the manufacturing process of the display cell array 14 is completed, the glass substrate 1 is completed by etching the short-circuit line 25 between the gate lines 16 by a photolithography process as shown in FIG. 2B.

Then, after bonding the glass substrate 1 and the counter substrate for liquid crystal injection, when the liquid crystal process is completed, as shown in FIG. 2B, the short line 25 of the data line 18 is cut by the glass substrate cutting process. You will complete the panel.

However, such a manufacturing process of the liquid crystal display device is a good solution to the static electricity during the manufacturing process of the display cell array 14, but the process performed after removing the short circuit (25), that is, the cell array glass for liquid crystal injection The static electricity generated in the bonding process of the substrate and the opposing substrate and other processes caused an incompatible problem.

Accordingly, an object of the present invention is to interconnect the power supply voltage applied to the gate driving circuit and the short circuit line of the data line in order to prevent the gate line and the data line from being shorted and then connect the power supply voltage with the switching element for discharging the gate line. The present invention provides a static electricity removing device of a liquid crystal panel capable of preventing an insulation breakdown caused by static electricity by discharging static electricity generated from a gate line to a power supply voltage or a short circuit through a switching element.

The technical means of the present invention for achieving the above object is a liquid crystal panel in which a gate and a data line for driving a display element and a driving circuit thereof are formed on an insulating substrate and used: a first power supply voltage and a second power supply voltage. First and second switching devices are connected in series between the first and second switching devices, and the first and second power supply voltages are connected in parallel with a short circuit line for electrostatic discharge, thereby preventing static electricity generated at a gate line connected to a common contact of the switching devices. It is characterized in that it is configured to discharge in a short line through the current path of the first or second switching element.

1 is a view showing a general liquid crystal panel and its driving circuit,

2A and 2B are conventional views showing an electrostatic removing device generated during the manufacture of a liquid crystal panel,

3 is an example of the gate driving circuit of FIG. 2;

4 is a view for explaining a static elimination method of the liquid crystal panel applied to the present invention,

5 is a view showing a static elimination circuit according to an embodiment of the present invention,

6 is a view showing a static elimination circuit according to another embodiment of the present invention,

7 is a view showing a static elimination circuit according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: glass substrate 110: shift register

120: gate driving circuit 130: display cell array

150: gate line 160: data line

170: short circuit

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

4 is a view illustrating a static electricity removing device of a liquid crystal panel according to the present invention, and a display including a plurality of shift registers 110, a gate driver circuit 120 for driving an image signal, and a plurality of thin film transistors as in the related art. The cell array 130 is manufactured on the glass substrate 100.

Here, a gate insulating film such as SiNx is formed on the front surface of the glass substrate 100 by chemical vapor deposition (PECVD) to electrically separate the gate line 150 and the data line 160.

In addition, the first and second power supply voltages VDD and VSS applied to the gate driving circuit 120 are connected to the short line 170 connected to the data line 160.

Here, as shown in FIG. 5, the switching element in the gate driving circuit 120 includes an N channel between the gate driving switching elements P1 and N1 and between the first power supply voltage VDD and the second power supply voltage VSS. The switching element TN1 and the switching element TP1 of the P-channel are connected in series, and the gate electrode and the source electrode which are the input terminal and the output terminal of the switching elements TN1 and TP1 are connected to the gate line 150.

That is, the drain electrode of the N-channel switching element TN1 is connected to the high power supply voltage VDD, and the drain electrode of the P-channel switching element TP1 is connected to the low power supply voltage VSS. The source and the gate electrode are connected to the gate line 150.

The potential of the gate line 150 is lower than or equal to the first power supply voltage VDD and higher than or equal to the second power supply voltage VSS in a normal state.

If static electricity is generated in the gate line 150 during the manufacturing process of the display cell array 130 or during the liquid crystal process, the potential of the gate line 150 is changed.

Accordingly, when the potential of the gate line 150 is high, the N-channel switching element TN1 operates, and when the potential of the gate line 150 is low, the P-channel switching element TP1 operates to operate the gate line 150. The charge is discharged through the short line 170 of the data line 160 after flowing to the first power supply voltage (VDD) or the second power supply voltage (VSS) to completely remove the static electricity.

FIG. 6 illustrates a second embodiment of the present invention, in which the N-channel switching device TN2 and the P-channel switching device TP2 are changed from those of FIG. 5, and the gate electrode of the P-channel switching device TP2 is formed in the second embodiment. It is connected to the first power supply voltage VDD, and the gate electrode of the N-channel switching element TN2 is connected to the second power supply voltage VSS.

Accordingly, when the potential of the gate line 150 is high, the P-channel switching element TP2 operates, and when the potential of the gate line 150 is low, the N-channel switching element TN2 operates to operate the gate line 150. The charge is discharged through the short line 170 of the data line 160 after flowing to the first power supply voltage (VDD) or the second power supply voltage (VSS) to completely remove the static electricity.

FIG. 7 illustrates an embodiment of the present invention using switching elements of the same channel (N channel). The gate electrode of the first switching element TN3 is connected to the gate line 150, and the second switching element TN4 The gate electrode is connected to the second power supply voltage VSS.

Accordingly, in the normal state, the voltage of the gate line 150 always has a value between the first power supply voltage VDD and the second power supply voltage VSS, but when the potential of the gate line 150 becomes high, the first When the switching device TN3 operates and the potential of the gate line 150 is low, the second switching device TN4 operates to charge the gate line 150 with the first power supply voltage VDD or the second power supply voltage VSS. After the flow to the discharge line through the short circuit line 170 of the data line 160 is completely removed static electricity.

Therefore, the short line 170 in the present invention is removed by the glass plate cutting method and dry etching after the LCD process is completed.

Therefore, in the present invention, the static electricity of the gate line generated during the thin film transistor process and the liquid crystal process can be discharged by connecting the discharge short-circuit with the power supply voltage of the gate driving circuit, thereby preventing the breakdown of the component due to the static electricity. It can be effective.

Claims (2)

In a liquid crystal display device comprising a gate driving circuit and a plurality of thin film transistors, The gate driving circuit includes an electrostatic discharge element provided between the gate bus line and the power electrode, The power electrode is connected to a short line Liquid crystal display device characterized in that. The method of claim 1, The electrostatic discharge device is composed of an n-channel and p-channel thin film transistor connected to a source and a gate, The drain electrode of the n-channel thin film transistor is connected to VDD of the power supply electrode, the drain electrode of the p-channel thin film transistor is connected to the VSS of the power supply electrode, and each source / gate electrode is connected to the gate bus line. Liquid crystal display device characterized in that.