KR20050069106A - Esd preventing sructure for liquid crystal display device - Google Patents

Abstract

The present invention relates to an antistatic circuit between a common line for applying a common voltage and a gate line for storage charge up in a pixel, and includes: a display area in which gate lines and data lines are arranged in a direction perpendicular to each other; A common line and a floating line formed around the display area to apply a common voltage, first and second dummy lines parallel to the common line, between each gate line and the first dummy line, And an antistatic element formed between a data line and the floating line, and between the second dummy line and a common voltage terminal, and an antistatic element or lightning rod formed between the first dummy line and the second dummy line. It is composed.

Description

ESD prevention sructure for liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to an antistatic circuit between a common line formed on a lower plate for applying a common voltage to an upper plate and a gate line for storage charge up to a pixel.

Liquid crystal display, one of the flat panel display elements, is an element that changes the optical anisotropy by applying an electric field to a liquid crystal that combines the liquidity and the optical properties of the crystal, and has a low power consumption and a large volume as compared to a conventional cathode ray tube. It is small and is widely used because it can be enlarged and fixed.

Such a liquid crystal display is largely divided into a liquid crystal panel displaying an image and a driving circuit unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal panel has a predetermined space and is bonded to the first and second substrates, 1 and a liquid crystal layer injected between the second substrates.

Such a liquid crystal display device has a variety of modes depending on the nature of the liquid crystal and the structure of the pattern.

That is, TN mode (Twisted Nematic Mode) for arranging the liquid crystal directors to be twisted by 90 ° and then applying voltage to control the liquid crystal directors, and dividing one pixel into several domains to realize the wide viewing angle by changing the main viewing angle direction of each domain. Multi-Domain Mode, OCB Mode (Optically Compensated Birefringence Mode), which compensates the phase change of light according to the direction of light by attaching a compensation film to the outer peripheral surface of the substrate, and two electrodes on one substrate. In-plane switching mode in which the directors of the liquid crystal are twisted in parallel planes of the alignment layer, and VA mode in which the long axis of the liquid crystal molecules is vertically aligned with the alignment layer plane using a negative liquid crystal and a vertical alignment layer. Vertical Alignment).

The most representative TN mode liquid crystal display and transverse electric field type liquid crystal display are described as follows.

1 is a plan view of a general TN mode liquid crystal display device, and FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1.

That is, the plurality of gate lines 12 arranged in one direction at regular intervals on the first substrate 11 and the plurality of gate lines 12 arranged at regular intervals in a direction perpendicular to the gate lines 12 to define pixel regions. A plurality of data lines 15, a plurality of pixel electrodes 17 formed in a matrix form in each pixel region, and a portion where the gate lines 12 and the data lines 15 cross each other to form the gate And a plurality of thin film transistors (TFTs) which are switched by the signals of the lines 12 and transfer the signals of the data lines 15 to the pixel electrodes 17.

The thin film transistor TFT may include a gate electrode 12a protruding from the gate line 12, and a gate insulating layer 13 formed on an entire surface of the first substrate including the gate electrode 12a and the gate line 12. ), A semiconductor layer 14 formed on the upper gate insulating layer 13 of the gate electrode 12a, a source electrode 15a protruding from the data line 15 to the semiconductor layer 14, and A drain electrode 15b formed on the other side of the semiconductor layer 14 opposite to the source electrode 15a is provided.

The pixel electrode 17 overlaps the neighboring gate line 12 to form a storage capacitor Cst.

The passivation layer 16 may have a contact hole on the drain electrode 15b on the upper surface of the thin film transistor, and a passivation layer 16 may be formed on the entire surface of the substrate, and may be connected to the drain electrode 15b through the contact hole. A pixel electrode 17 is formed in each pixel region on 16, and a first alignment layer (not shown) is formed on the entire surface of the substrate including the pixel electrode 17 and subjected to rubbing.

 The second substrate 20 includes a black matrix layer 21 for blocking light in portions other than the pixel region, and R, G, and B color filter layers 22 for expressing color in each pixel region. ) And a common electrode 24 and a second alignment layer (not shown) are formed on the entire surface of the substrate including the color filter layer 22.

Such first and second substrates 11 and 20 maintain a constant cell gap by a spacer (not shown) and are sealed to a sealant (not shown). The liquid crystal layer 19 is formed between the two substrates 11 and 20 by bonding.

The outermost gate line Vgl of the liquid crystal display of the TN mode is not for driving the thin film transistor but for overlapping the adjacent pixel electrode 17 to form the storage capacitor Cst.

3 is an equivalent circuit diagram for explaining an antistatic structure of a conventional TN mode liquid crystal display, and FIG. 4 is an equivalent circuit diagram of a conventional antistatic element.

That is, the gate lines and the data lines are all formed independently and exposed to the outside until the tape carrier package (TCP) is attached in the module process, so that in case of electrostatic discharge (ESD), a short circuit of each signal line and Damage to the device inside the thin film transistor array may occur.

In order to prevent such static electricity, a separate antistatic structure is required for the thin film transistor array.

That is, as described above, the gate line 12 and the data line 15 are arranged in a direction perpendicular to each other in the display area AR of the lower substrate. In addition, a gate pad portion and a data pad portion for applying a driving signal are respectively formed on one side of the gate line and one side of the data line of the non-display area around the display area, and non-display of the opposite sides of the gate pad portion and the data pad portion. In the region, a common line 28 and a floating line 29 are formed to apply a common voltage to the common electrode (24 of FIG. 2) formed on the upper substrate, and are parallel to the common line 28. The dummy line 27 is formed. Here, the outermost gate line Vgl is not intended to drive the thin film transistor, but overlaps the adjacent pixel electrode 17 to form a storage capacitor Cst.

In addition, the other end of each gate line 12 and the dummy line 27 is connected by an antistatic element 30a, and the other end of the data line 15 and the floating line 29 are also antistatic The common line 28 and the floating line 29 are also connected by an antistatic element 30c, and the dummy line 27 and the common line 28 are also connected by an element 30b. Is connected by an antistatic element (30d). The outermost gate line Vgl is directly connected to the dummy line 27.

Here, the antistatic elements 30a, 30b, 30c, and 30d are formed in the same structure, and the configuration thereof is as shown in FIG.

That is, FIG. 4 illustrates an antistatic device 30c formed between the floating line 29 and the common line 28, and includes a first transistor Q1 having a gate terminal and a source terminal connected to the common line 28. And a second transistor Q2 having a gate terminal and a drain terminal connected to the floating line 29, and a source terminal connected to the drain terminal of the first transistor Q1, and following the common line 28. A source transistor and a drain terminal are respectively connected to the line 29, and a third transistor Q3 is connected to the source terminal of the second transistor Q2. The antistatic elements 30a, 30b, 30c, and 30d thus constructed each have a high resistance characteristic.

However, in the antistatic structure of the conventional liquid crystal display device, there are the following problems.

That is, since the outermost gate line Vgl for forming the storage capacitor Cst is directly connected to the dummy line, and the dummy line and the common line are connected by one antistatic element, a liquid crystal panel is manufactured. When external static electricity flows into the internal liquid crystal panel, the outermost gate line Vgl is easily damaged by the introduced static electricity, which causes short circuits between the common line and the gate line Vgl. This will cause poor driving.

In order to solve the above problems, the present invention provides an antistatic structure of a liquid crystal display device that can protect a liquid crystal panel from static electricity by forming a double antistatic structure on the outermost gate line for forming a storage capacitor or by applying a lightning rod structure. The purpose is to provide.

The antistatic structure of the liquid crystal display according to the present invention for achieving the above object is a display region in which gate lines and data lines are arranged in a direction perpendicular to each other, and formed around the display region to apply a common voltage. A common line and a floating line, a first and a second dummy line formed parallel to the common line, between each gate line and the first dummy line, between the data line and the floating line, and the first dummy line. And antistatic elements formed between the second dummy line and the second dummy line and between the second dummy line and the common voltage terminal.

In addition, the antistatic structure of the liquid crystal display according to the present invention for achieving the above object, the display area in which the gate line and the data line is arranged in a direction perpendicular to each other, and formed around the display area to provide a common voltage A common line and a floating line for application, first and second dummy lines formed parallel to the common line, between each gate line and the first dummy line, between the data line and the floating line, and the first Another feature is that it includes antistatic elements formed between the second dummy line and the common voltage terminal, and a lightning rod formed between the first dummy line and the second dummy line.

The antistatic structure of the liquid crystal display according to the present invention having the above characteristics will be described in more detail with reference to the accompanying drawings.

5 is an equivalent circuit diagram of a liquid crystal display for explaining an antistatic structure according to the first embodiment of the present invention.

As described above, the gate line 112 and the data line 115 are arranged in a direction perpendicular to each other in the display area AR.

In addition, a gate pad portion and a data pad portion for applying a driving signal are formed on one side of the gate line 112 and one side of the data line 115 in the non-display area around the display area, respectively. A common line 128 and a floating line 129 for applying a common voltage are formed in the non-display area opposite to the data pad part, and the first dummy line 127a and the first dummy line 127a are parallel to the common line 128. The second dummy line 127b is further formed.

In addition, the other end of each gate line 112 and the first dummy line 127a are connected by an antistatic element 130a, and the other end of the data line 115 and the floating line 129 are also The common line 128 and the floating line 129 are also connected by the antistatic element 130c, and the first dummy line 127a and the second dummy are connected by the antistatic element 130b. Line 127b is also connected to at least one (two) antistatic element 130d, and the second dummy line 127b and the common voltage terminal 131 are also at least one (two) antistatic It is connected by the element 130e.

Here, the outermost gate line Vgl is directly connected to the first dummy line 127a, and the antistatic devices 130a, 130b, 130c, 130d, and 130e are illustrated in FIG. 4.

In this way, the dummy line is further configured, at least one antistatic element is formed between the first dummy line 127a and the second dummy line 127b, and the second dummy line 127b and the common voltage terminal ( At least one antistatic element is formed between the 131 to form a double antistatic structure between the common voltage terminal and the outermost gate line (Vgl), thereby preventing short circuit of the common voltage terminal and the outermost gate line even when static electricity is generated. can do.

6 shows an equivalent circuit of the antistatic structure of the liquid crystal display according to the second embodiment of the present invention.

In the second embodiment of the present invention, in the first embodiment of the present invention, at least one (two) lightning arresters 132a and 132b instead of the antistatic element between the first dummy line 127a and the second dummy line 127b. ) Is formed.

That is, as described above, the gate line 112 and the data line 115 are arranged in a direction perpendicular to each other in the display area AR.

In addition, a gate pad portion and a data pad portion for applying a driving signal are formed on one side of the gate line 112 and one side of the data line 115 in the non-display area around the display area, respectively. A common line 128 and a floating line 129 for applying a common voltage are formed in the non-display area opposite to the data pad part, and the first dummy line 127a and the first dummy line 127a are parallel to the common line 128. The second dummy line 127b is further formed.

In addition, the other end of each gate line 112 and the first dummy line 127a are connected by an antistatic element 130a, and the other end of the data line 115 and the floating line 129 are also The common line 128 and the floating line 129 are also connected by the antistatic element 130c, and the second dummy line 127b and the common voltage are connected by the antistatic element 130b. The terminal 131 is also connected by at least one (two) antistatic elements 130e.

At least one (two) lightning arresters 132a and 132b are formed between the first dummy line 127a and the second dummy line 127b.

Here, the outermost gate line Vgl is directly connected to the first dummy line 127a, and the antistatic devices 130a, 130b, 130c, and 130e are illustrated in FIG. 4.

As the lightning arresters 132a and 132b are formed between the first dummy line 127a and the second dummy line 127b as described above, the short circuit of the common voltage terminal and the outermost gate line due to static electricity can be prevented and the internal element Can protect.

The antistatic structure of the liquid crystal display device according to the present invention as described above has the following effects.

In other words, the dummy line is additionally configured to double the antistatic structure or form a lightning rod between the outermost gate line for implementing the common voltage terminal and the storage capacitor, thereby preventing a short between the common voltage terminal and the outermost gate line from static electricity. In addition, the internal device can be protected.

1 is a plan view of a typical TN mode liquid crystal display device

FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1.

3 is an equivalent circuit diagram illustrating an antistatic structure of a conventional TN mode liquid crystal display device.

4 is an equivalent circuit diagram of a conventional antistatic device

5 is an equivalent circuit diagram of a liquid crystal display for explaining an antistatic structure according to the first embodiment of the present invention.

6 is an equivalent circuit diagram of a liquid crystal display for explaining an antistatic structure according to a second embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

112: gate line 115: data line

127a, 127b: dummy line 128: common line

129: floating line 130a-130e: antistatic element

131: common voltage terminal 132a, 132b: lightning rod

Claims (10)

 A display area in which gate lines and data lines are arranged in a direction perpendicular to each other; A common line and a floating line formed around the display area to apply a common voltage; First and second dummy lines formed in parallel to the common line, An antistatic device is formed between the gate line and the first dummy line, between the data line and the floating line, between the first dummy line and the second dummy line, and between the second dummy line and the common voltage terminal. Antistatic structure of the liquid crystal display device comprising a. The method of claim 1, And at least one antistatic element is formed between the first dummy line and the second dummy line. The method of claim 1, And at least one antistatic element is formed between the second dummy line and the common voltage terminal. The method of claim 1, And an antistatic element is formed between the floating line and the common line. The method of claim 1, The outermost gate line for forming the storage capacitor of the gate line is directly connected to the first dummy line, the antistatic structure of the liquid crystal display device.  A display area in which gate lines and data lines are arranged in a direction perpendicular to each other; A common line and a floating line formed around the display area to apply a common voltage; First and second dummy lines formed in parallel to the common line, Antistatic elements formed between the gate line and the first dummy line, between the data line and the floating line, and between the second dummy line and the common voltage terminal; And a lightning arrester formed between the first dummy line and the second dummy line. The method of claim 6, At least one lightning rod is formed between the first dummy line and the second dummy line, the antistatic structure of the liquid crystal display device. The method of claim 6, And at least one antistatic element is formed between the second dummy line and the common voltage terminal. The method of claim 6, And an antistatic element is formed between the floating line and the common line. The method of claim 6, The outermost gate line for forming the storage capacitor of the gate line is directly connected to the first dummy line, the antistatic structure of the liquid crystal display device.