KR100603853B1 - Liquid crystal display device with antistatic circuit - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having antistatic means for preventing a short circuit when breakdown of an insulating layer by static electricity occurs in an active panel. According to the present invention, a gate wiring and a data wiring perpendicular to each other with an insulating film interposed therebetween, antistatic means connected to the gate wiring and the data wiring, gate short circuit wiring and data short circuit wiring connected to the antistatic means, A liquid crystal display device includes at least one auxiliary antistatic means provided in each of the gate short circuit and the data short circuit. According to the present invention, even if the electrostatic short circuit is damaged by external impact in the completed liquid crystal display device, the probability of occurrence of a short circuit between each wiring and the short circuit is minimized.

Description

Liquid crystal display device with antistatic circuit

The present invention relates to an active panel structure that prevents shock from static electricity in an active matrix liquid crystal display (AMLCD) in which an active switching element is installed. In particular, the present invention relates to a liquid crystal display device having an antistatic means for preventing a short circuit when breakdown of an insulating film by static electricity occurs in an active panel.

Among the display devices that display image information on the screen, the CRT (or Cathode Ray Tube (CRT)) has been the most used so far, which is inconvenient to use because it is bulky and heavy compared to the display area. Therefore, even if the display area is large, the thin film type flat panel display device which has a small thickness and can be easily used in any place has been developed, and is gradually replacing the CRT display device. In particular, the liquid crystal display (or liquid crystal display) has the highest resolution than other flat panel displays, and the quality of the moving picture is faster than that of CRT. to be.

The driving principle of the liquid crystal display device is to use the optical anisotropy and polarization property of the liquid crystal. Since the structure is thin and long, the direction of the molecular arrangement can be controlled by artificially applying an electromagnetic field to liquid crystal molecules having directionality and polarization in the molecular arrangement. Accordingly, when the alignment direction is arbitrarily adjusted, light may be transmitted or blocked in accordance with the arrangement direction of the liquid crystal molecules by optical anisotropy of the liquid crystal, thereby applying the screen display device. Nowadays, active matrix liquid crystal displays, in which thin film transistors (or TFTs) and pixel electrodes connected thereto are arranged in a matrix manner, are attracting attention because of their excellent image quality and natural color. The structure of the liquid crystal panel, which is a basic component of a general liquid crystal display, will be described in detail as follows. For convenience of explanation, a cross-sectional view taken along cut line II-II of FIG. 1 and FIG. 1 showing a perspective view of the liquid crystal display will be described with reference to FIG.

In the liquid crystal panel, two panels 3 and 5 provided with various elements are attached to each other, and the liquid crystal 10 layer is sandwiched therebetween. One panel of the liquid crystal display includes elements that implement color. This is often called "color filter panel 3". In the color filter panel 3, red, green, and blue color filters 7 are sequentially arranged according to the positions of pixels designed in a matrix arrangement on the first transparent substrate 1a. have. Between these color filters 7, a very fine black matrix 9 is formed. This prevents the appearance of mixed colors between each color. And the common electrode 8 which covers the color filter 7 is formed. The common electrode 8 serves as one electrode for forming an electric field applied to the liquid crystal.

The other panel of the liquid crystal panel is provided with switching elements and wirings for generating an electric field for driving the liquid crystal. This is often referred to as "active panel 5". In the active panel 5, the pixel electrodes 47 are formed on the second transparent substrate 1b according to positions of pixels designed in a matrix manner. The pixel electrode 47 faces the common electrode 8 formed on the color filter panel 3 and serves as the other electrode forming an electric field applied to the liquid crystal 10. The signal wires 13 are formed along the horizontal array direction of the pixel electrodes 47, and the data wires 23 are formed along the vertical array direction. In the active matrix liquid crystal display device, a thin film transistor which is a switching element for applying an electric field signal to the pixel electrode 47 is formed in one corner of the pixel electrode 47. In the case of an active matrix liquid crystal display device, the gate electrode 11 of the thin film transistor is connected to the signal wiring 13 (hence the signal wiring is also referred to as "gate wiring"), and the source electrode 21 is It is connected to the data line 23 (hence the data line is also called "source line"). The drain electrode 31 of the thin film transistor is connected to the pixel electrode 47. In the thin film transistor, a semiconductor layer 33 is formed between the source electrode 21 and the drain electrode 31, and the source electrode 21 and the semiconductor layer 33, and the drain electrode 31 and the semiconductor layer 33 are formed. Are each in ohmic contact. At the ends of the gate wiring 13 and the source wiring 23, gate pads 15 and source pads 25, which are terminal terminals (or terminals) for receiving signals applied from the outside, are formed, respectively.

When an external electrical signal applied to the gate pad 15 is applied to the gate electrode 11 along the gate wiring 13, the semiconductor layer 33 is activated and the image information applied to the source pad 25 is applied to the source wiring ( It is conducted from the source electrode 21 to the drain electrode 31 along the 23. On the other hand, when no signal is applied to the gate wiring 23, the source electrode 21 and the drain electrode 31 are disconnected. Therefore, whether the data signal is applied to the drain electrode 31 can be determined by adjusting the signal of the gate electrode 11. Therefore, the data signal can be artificially transferred to the pixel electrode 47 connected to the drain electrode 31. That is, the thin film transistor serves as a switch for driving the pixel electrode 47. A gate insulating film 17 is formed between the layer on which the gate wiring 13 and the like are formed and the layer on which the source wiring 23 and the like are formed, and a protective film for protecting the device even on the layer on which the source wiring 23 and the like are formed. (37) is formed.

The two panels (the color filter panel 3 and the active panel 5) thus made are attached to each other at a predetermined interval (referred to as "cell gap"), and the liquid crystal 10 is interposed therebetween. ) The material is filled. In order to keep the cell gap between the two panels constant and to prevent the liquid crystal material from leaking out, the edge portions of the two substrates are sealed with a seal 81 such as epoxy. Thus, the liquid crystal panel which is the main part of the liquid crystal display device is completed. In general, the color filter panel 3 and the active panel 5 are bonded to the seal 81 material, and after the liquid crystal 10 is injected, a pad (for attaching an external input terminal to the pad portion of the active panel 5) is used. 15, 25) The part of the color filter panel 3 covering the part is cut off to open the pad part (Figs. 1 and 2).

In manufacturing such a liquid crystal display device, there is a possibility that high-pressure static electricity is generated in the manufacturing environment. Since various wirings, TFTs, and the like formed on the active panel can be destroyed by such high-pressure static electricity, a prevention means is necessary. In the related art, an antistatic circuit is provided on each of the scan line and the signal line, and the antistatic circuit is connected to a common short circuit line. In addition, the conventional antistatic circuit is improved, and the antistatic circuit formed on the scan line and the antistatic circuit formed on the signal line are stabilized and connected to separate short circuit lines in order to improve detection power in the inspection process of the substrate. The present applicant has filed a liquid crystal display device with the Korean Patent Office under the application number 97-00459. Looking at the structure of the active panel having a conventional antistatic circuit in detail as shown in FIG.

The gate wiring 13 and the data wiring 23 are orthogonally formed on the transparent insulating substrate 1 with an insulating film (not shown) interposed therebetween. The thin film transistor 19 and the pixel electrode 47 are formed in the intersection part. The gate short circuit 93 is connected to the gate wiring 13 through the antistatic circuit 91, and the data short circuit 83 is connected through the data wiring 23 and the antistatic circuit 91. It is connected. The antistatic circuit 91 may use, for example, a structure such as the equivalent circuit illustrated in FIG. 4.

A gate voltage for driving the thin film transistor 19 is applied to the gate electrode 11 branched from the gate line 13 through the gate pad 15. At this time, a low level voltage, V _gl , of the scan voltages applied to the gate wiring 13 is applied to the gate shorting wiring 93 through the gate shorting wiring pad 95 so that the gate wiring ( The antistatic circuit 91 connected between the 13 and the gate short circuit 93 is stabilized. In addition, the data short-circuit 83 is applied with a voltage Vcom applied to the common electrode 8 through the data short-circuit pad 85 to prevent static electricity connected between the data line 23 and the data short-circuit 83. The prevention circuit 91 is stabilized.

In the liquid crystal display device having the conventional antistatic circuit, there is no method to prepare for the destruction when the antistatic circuit is caused by an external electric or physical shock. That is, when the electrostatic circuit is damaged by an external shock, the gate short circuit or the data short circuit and the electrostatic circuit may be shorted or open. If a disconnection occurs, no particular problem occurs and thus does not affect the liquid crystal display. However, when a short circuit occurs, a problem arises in quality when the liquid crystal display is driven. Specifically, if a short circuit occurs when the electrostatic circuit between the gate wiring and the gate short circuit is broken, the voltage applied to the gate short circuit, that is, the voltage V _gl is always applied to the gate wiring, so that the gate wiring is disconnected in the middle. The same screen failure occurs. In addition, if a short circuit occurs while the electrostatic circuit between the data wiring and the data short circuit is broken, a voltage applied to the data short circuit, that is, a Vcom voltage, is always applied to the data wiring, causing a defect in driving the liquid crystal.

SUMMARY OF THE INVENTION An object of the present invention is to provide an antistatic circuit which reduces the probability of a short circuit occurring between two wires connected via an antistatic circuit when an antistatic circuit is destroyed by an external impact. Another object of the present invention is to provide an antistatic circuit that prevents a short circuit between two wires even if the antistatic circuit is destroyed by an external impact.

In order to solve the problems of the conventional liquid crystal display and to achieve the above object, the liquid crystal display according to the present invention comprises a gate wiring and a data wiring perpendicular to each other with an insulating film interposed therebetween on the substrate, and the gate wiring and the data. And antistatic means connected to the wirings, gate short circuit and data short circuits connected to the antistatic means, and at least one auxiliary antistatic means provided in each of the gate short circuit and the data short circuits. do.

Therefore, in the present invention, even if the antistatic means connected between the gate wiring and the gate short circuit or the antistatic means connected between the data wiring and the data short circuit are destroyed by an external shock, the gate wiring and the gate short circuit are prevented by the auxiliary antistatic means. There is no short circuit or data wiring and data short wiring. It will be described in detail with reference to the embodiment shown in Figure 5 showing a plan view of a liquid crystal display device having an antistatic circuit according to the present invention.

The gate wiring 113 and the data wiring 123 are orthogonally formed on the transparent insulating substrate 101 with an insulating film (not shown) interposed therebetween. The thin film transistor 119 and the pixel electrode 147 are formed at the intersection thereof. The gate short circuit 193 is connected to the gate line 113 through the antistatic circuit 191, and the data short circuit 183 is connected through the data line 123 and the antistatic circuit 191. have. The gate short circuit 193 or the data short circuit 183 itself includes at least one auxiliary antistatic circuit 199. In this case, the auxiliary antistatic circuit 199 may include the respective short circuit pads 195 and 185 and the respective short circuits 193 and 183 for receiving a voltage applied to the gate short circuit 193 or the data short circuit 183. Preferably between the beginning of the In addition, an auxiliary antistatic circuit 199 may be further included at an intermediate position of the gate short circuit 193 and the data short circuit 183. As an example of the antistatic circuit 191 and the auxiliary antistatic circuit 199, a structure such as the equivalent circuit shown in FIG. 4 may be used as in the conventional antistatic circuit.

A gate voltage is applied to the gate electrode 111 connected to the gate wiring 113 through the gate pad 115 to drive the thin film transistor 119. In this case, a low level voltage, ie, V _gl , of the gate voltages applied to the gate wiring 113 is applied to the gate short circuit wiring 193 through the gate short circuit wiring pad 195 to allow the gate to be applied. The antistatic circuit 191 connected between the wiring 113 and the gate short circuit 193 is stabilized. The data short-circuit 183 is applied with a voltage Vcom applied to the common electrode 108 through the data short-circuit pad 185 to prevent static electricity connected between the data line 123 and the data short-circuit 183. Stabilization circuit 191 is stabilized. In the present invention, even if the antistatic circuit 191 is damaged by an external electrical or physical shock, no defect occurs in the gate wiring 113 or the data wiring 123 unless the auxiliary antistatic circuit 199 is damaged. .

For example, even if an antistatic circuit connected between any one of the gate wirings and the gate shorting circuit is broken, the voltage of the gate shorting wiring to the gate wiring is caused by the auxiliary antistatic circuit connected between the gate shorting pad and the gate shorting wiring. V _gl is not applied. In addition, even if one of the antistatic circuits connected between any one data line and the data short circuit is broken, the auxiliary antistatic circuit connected between the data short circuit pad and the data short circuit causes the voltage Vcom, which is the voltage of the data short circuit, to appear in the data lines. It is not authorized.

The present invention relates to an antistatic circuit in a liquid crystal display device. In the liquid crystal display device having an antistatic circuit formed between the short circuit and the wiring to prevent the wiring and the switching elements from being damaged by static electricity, the present invention further comprises at least one auxiliary protection circuit in the short circuit itself; When the antistatic circuit is broken, it reduces the probability of short circuit and wiring shorting to each other. Therefore, even if the completed liquid crystal display device is damaged due to an external impact, the electrostatic short circuit can be expected to have an effect of not directly affecting the quality of the liquid crystal display device. Moreover, when manufacturing a liquid crystal display device, the effect which manufacture yield improves can be acquired.

1 is a perspective view showing a general structure of a liquid crystal display device.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 to show a general structure of a liquid crystal display.

3 is a plan view schematically showing a conventional liquid crystal display device in which a gate wiring, a data wiring, a gate short circuit, a data short circuit, and an antistatic circuit are formed on a substrate.

4 is a view showing an equivalent circuit of the antistatic circuit used in the conventional liquid crystal display device.

5 is a plan view schematically illustrating a liquid crystal display device in which a gate wiring, a data wiring, a gate short circuit, a data short circuit, and an antistatic circuit are formed on a substrate according to the present invention.

<Description of the reference numerals for the main parts of the drawings>

1, 101: substrate 1a: first substrate

1b: second substrate 3: color filter panel

5: active panel 7: color filter

8: common electrode 9: black matrix

10 liquid crystal 11, 111 gate electrode

13, 113: gate wiring 15, 115: gate pad

17: gate insulating film 19, 119: thin film transistor

21, 121: source electrode 23, 123: source wiring

25, 125: source pads 31, 131: drain electrodes

33: semiconductor layer 37: protective film

47, 147: pixel electrode 57: gate pad terminal

67: source pad terminal 81: seal

83, 183: data short circuit wiring 85, 185: data short circuit wiring pad

91, 191: antistatic circuit 93, 193: gate short circuit

95, 195: gate short circuit pad 199: auxiliary antistatic circuit

Claims (15)

First and second substrates facing each other with a liquid crystal layer interposed therebetween, A plurality of gate lines and data lines intersecting at the inner surface of the first substrate to define pixels; A plurality of first antistatic means connected to the gate wiring; A gate short wiring connected to the gate wiring through the first antistatic means and to which a first voltage is applied; First and second antistatic means interposed between the gate short circuit and at least two gate short circuits; A plurality of second antistatic means connected to the data line; A data short wiring connected to the data wiring through the second antistatic means and to which a second voltage is applied; At least one second anti-static means interposed between the data short circuit and at least two data short circuits; Liquid crystal display comprising a. The method of claim 1, A thin film transistor formed at an intersection point of the gate line and the data line: Pixels connected to the thin film transistors one-to-one and mounted on the respective pixels. An electrode; A common electrode formed on an inner surface of the second substrate and to which a common voltage is applied Liquid crystal display further comprising. The method of claim 2, The first voltage is an off voltage of the thin film transistor; And the second voltage is the common voltage. The method of claim 1, And the first and second antistatic means each include one or more nonlinear elements. The method of claim 1, The first and second antistatic means may include at least one thin film transistor having a gate electrode, a source electrode, and a drain electrode, respectively. The method of claim 5, The first antistatic means includes: a first thin film transistor having a first drain electrode, a first gate electrode connected to the gate short circuit, and a first source electrode; A second thin film transistor having a second source electrode connected to the first drain electrode, a second gate electrode connected to the gate wiring, and a second drain electrode; A third thin film transistor having a third gate electrode connected to a contact between the first drain electrode and a second source electrode, a third source electrode connected to the gate short interconnection, and a third drain electrode connected to the gate interconnection Liquid crystal display comprising a. The method of claim 5, The second antistatic means includes: a first thin film transistor having a first drain electrode, a first gate electrode connected to the data short circuit, and a first source electrode; A second thin film transistor having a second source electrode connected to the first drain electrode, a second gate electrode connected to the data wiring, and a second drain electrode; A third thin film transistor having a third gate electrode connected to a contact between the first drain electrode and a second source electrode, a third source electrode connected to the data short circuit, and a third drain electrode connected to the data wiring Liquid crystal display comprising a. The method of claim 1, And the first and second auxiliary antistatic means each including one or more nonlinear elements. The method of claim 1, And the first and second auxiliary antistatic means respectively include a thin film transistor having a gate electrode, a source electrode, and a drain electrode. The method of claim 9, The first auxiliary antistatic means may include: a first thin film transistor having a first drain electrode, a first gate electrode connected to a separated side of the gate short circuit, and a first source electrode; A second thin film transistor having a second source electrode connected to the first drain electrode, a second gate electrode connected to the other side of the gate short circuit, and a second drain electrode; A third gate electrode connected to a contact between the first drain electrode and a second source electrode, a third source electrode connected to one side of the gate short interconnection, and a third drain connected to the other side of the gate short interconnection Third Thin Film Transistor with Electrode The method of claim 9, The second auxiliary antistatic means includes: a first thin film transistor having a first drain electrode, a first gate electrode connected to a separated side of the data short circuit, and a first source electrode; A second thin film transistor having a second source electrode connected to the first drain electrode, a second gate electrode connected to the other side of the data short circuit, and a second drain electrode; A third gate electrode connected to a contact between the first drain electrode and a second source electrode, a third source electrode connected to one side of the data short circuit, and a third drain connected to the other side of the data short line; Third Thin Film Transistor with Electrode Liquid crystal display comprising a. The method of claim 1, And the first voltage is applied at both ends of the gate short line. The method of claim 12, The gate wiring is connected to the gate short wiring one by one by means of first antistatic means in the order of Gl, G2 ... Gm, and in the order of Al, A2 ... Am, respectively. Each of the first auxiliary antistatic means includes one contact before the contact point connected to the Al th first antistatic means, a contact point connected to the Al th first antistatic means, and a contact point connected to the Am th antistatic means. And at least one terminal between the first and second terminals after the contact point connected with the first Am protection means. The method of claim 1, And the second voltage is applied at both ends of the data short circuit. The method of claim 14, The data line is connected one-to-one to the data short line by second anti-static means in order of Dl, D2 .... Dn, and in the order of B1, B2 ... Bn, respectively. Each of the second auxiliary antistatic means includes a contact point connected to the Bl th second antistatic means, a contact point connected to the Bl th second antistatic means, and a contact point connected to the Bn th second antistatic means, respectively. And at least one between and one end after the contact point connected to the Bn-th second antistatic means.