JPH0511276A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which obviates the generation of display defects even if a dielectric breakdown is generated by the generation of static electricity. CONSTITUTION:The patterning of a lower metal 4 to constitute wiring electrodes 2 and nonlinear resistance elements 3 on a glass substrate 1 is executed. Plural groups of wiring parts 5 for drawing out and pad parts 6 for external connection of parallel equal pitches are formed. The oxide film of the nonlinear resistance elements 3 is formed on the front surface of the lower metal 4. The patterning of the upper metal 7 of the nonlinear resistance elements 3 is executed. After the thin film of ITO is formed over the entire surface, picture element display electrodes 8 are patterned. The ITO films 9 are made to remain on the pad parts 6 as well and pattern parts 10 of the solid films of a conductor are disposed between the adjacent pad parts 6 and 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a metal-insulator-metal non-linear resistance element provided as a switching element on a substrate.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have come from relatively small capacity devices such as watches and calculators to personal computers,
It has been used for word processors, terminal devices for office automation, and high-capacity display applications such as television image display.

In the conventional liquid crystal display device,
It is common to use a multiplex drive system for matrix display, a so-called simple matrix system. However, this simple matrix method is not suitable for large-scale matrix display because the contrast ratio between the display portion and the non-display portion deteriorates as the number of scanning lines increases.

Therefore, a so-called active matrix system has been developed in which each pixel is driven by a switching element. A thin film transistor or a non-linear resistance element is used as the switching element. Among them, the non-linear resistance element is basically two terminals and has a simple structure, which is advantageous in terms of manufacturing cost.

Various types of nonlinear resistance elements have been developed. Among them, only those having a metal-insulator-metal structure have been put into practical use at present. There is.

A conventional liquid crystal display device having a non-linear resistance element having a metal-insulator-metal structure will be described.

First, tantalum (Ta) is formed on the glass substrate 1.
After forming a thin film of the first metal layer consisting of by the sputtering method, by the first photolithography step,
As shown in FIG. 3, patterning is performed on the wiring electrode 2 and the lower metal 4 constituting the nonlinear resistance element 3 protruding from the wiring electrode 2 in the vertical direction. Simultaneously with this, as shown in FIG. 7, a plurality of groups of wirings 5 having equal pitches for drawing out and a pad portion 6 which is a wiring electrode are formed.

Next, the non-linear resistance element 3 is formed on the surface of the lower metal 4 formed of the first metal layer by using the anodic oxidation method or the like.
Forming an oxide film as an insulating film.

Further, a second metal layer to be the upper metal 7 of the non-linear resistance element 3 is formed into a thin film on the entire surface by a sputtering method, and then a second photolithography process is used, as shown in FIG. Patterning is performed on the upper metal 7 of the non-linear resistance element 3 which intersects with each other.

Finally, after forming a thin film of ITO (Indium Tin Oxide) on the entire surface, the pixel display electrode 8 is patterned by the third photolithography process as shown in FIG. At this time, as shown in FIG. 7, the liquid crystal display device is formed by leaving the ITO film 9 also on the pad portion 6.

[0011]

On the other hand, when the non-linear resistance element 3 is used as a switching element as in the present liquid crystal display device, a display defect of the pixel display electrode 8 unit becomes a so-called point defect as a characteristic defect of the element.

Various factors may be considered for the defective characteristics of the element, but metal-insulator-metal (Metal-Insulator-Me
In the non-linear resistance element 3 which is a MIM element having a (tal) structure, since the oxide film which is an insulating film is as thin as about 500 to 700 angstroms, the withstand voltage is low, and dielectric breakdown is likely to occur due to static electricity generated during the process. In addition,
During the array process of the liquid crystal display device, each wiring electrode 2 is short-circuited by a short ring (not shown) on the outside of the pad portion 6, and thus is relatively resistant to static electricity.

However, since the short ring is cut off after the cell is formed in the liquid crystal display device, each wiring electrode 2 is electrically independent after the cell is formed, and is protected from static electricity. Therefore, when static electricity is generated from the cell process to the module process, dielectric breakdown of the nonlinear resistance element 3 which is a switching element connected to the wiring electrode 2 is caused via the pad portion 6, and as a result, along the wiring electrode 2. Point defects may occur.

In particular, as in the liquid crystal display device shown in FIG.
When the pad portion 6 is divided into a plurality of groups,
Between the groups of the pad portions 6, the glass surface is exposed and static electricity is easily generated. As a result, the pad portion 6 of the divided portion, that is, the nonlinear resistance element 3 on the wiring electrode 2 connected to both ends of the group of the pad portion 6 is likely to cause dielectric breakdown. Therefore, as shown in FIG. 8, when static electricity is generated between the pad portions 6 and 6 at both ends of the group,
There is a problem in that dielectric breakdown occurs in the portion marked with X, resulting in a display defect. .

The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device in which a display defect is less likely to occur even if static electricity is generated and insulation breakdown occurs.

[0016]

A liquid crystal display device according to the present invention includes a plurality of pixel display electrodes, a metal-insulator-metal nonlinear resistance element electrically connected to the plurality of pixel display electrodes, In a liquid crystal display device in which electrode terminals connected to the non-linear resistance element by wiring electrodes for each of a plurality of groups of equal pitch are formed on a substrate, a conductor is arranged between the groups of electrode terminals. is there.

[0017]

The present invention suppresses the generation of static electricity on the substrate between the groups of electrode terminals by arranging the conductor pattern between the groups of electrode terminals, and prevents electrostatic breakdown at the ends of the groups. Prevent display defects of pixel display electrodes.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the liquid crystal display electrode of the present invention will be described below with reference to the drawings.

Similar to the conventional example, first, a thin film of a first metal layer made of tantalum (Ta) is formed on a glass substrate 1 by a sputtering method, and then a first photolithography process is performed, as shown in FIG. Then, patterning is performed on the wiring electrode 2 and the lower metal 4 constituting the non-linear resistance element 3 protruding from the wiring electrode 2 in the vertical direction. At this time, at the same time, as shown in FIG. 2, a wiring portion 5 for drawing out and a pad portion 6 which is an electrode portion for external connection are formed for a plurality of groups having an equal pitch.

Next, the non-linear resistance element 3 is formed on the surface of the lower metal 4 formed of the first metal layer by using the anodic oxidation method or the like.
Forming an oxide film as an insulating film.

Further, a second metal layer to be the upper metal 7 of the non-linear resistance element 3 is formed into a thin film on the entire surface by a sputtering method, and then a second photolithography process is used, as shown in FIG. Patterning is performed on the upper metal 7 of the non-linear resistance element 3 which intersects with each other.

Finally, after forming a thin film of ITO (Indium Tin Oxide) on the entire surface, the pixel display electrode 8 is patterned by the third photolithography process as shown in FIG. At this time, as shown in FIG. 1, the ITO film 9 is left on the pad portion 6 and the pattern portion 10 of the solid film of the conductor is arranged between the adjacent pad portions 6 and 6 to form the liquid crystal display device. In the above-described embodiment, the pattern portion 10 arranged between the pad portions 6 and 6 is made of the material I of the pixel display electrode 8.
It uses TO. This is the outer lead bonding (Outer Lead Bonding) of the TAB method at both ends of the group of pad portions 6.
Considering the case of arranging the alignment mark for Bonding), since the optical alignment is normally performed, even if the pattern part 10 is arranged between the groups of the pad parts 6, no optical interference occurs. This is because.

In the case where the above optical alignment is not performed, the pattern arranged between the groups of the pad portions 6 may be any of the conductors of the first metal layer, the second metal layer and the ITO, and the same effect can be obtained. Is obtained.

According to the above-mentioned embodiment, as shown in FIG. 6, since the generation of static electricity is suppressed on the substrate 1 between the groups of the pad portions 6 and 6, the nonlinear resistance element 3 serving as a switching element via the wiring electrode 2 is formed. Since no static electricity due to dielectric breakdown is generated, it is difficult for a display defect to occur in the pixel display electrode 8.

[0025]

According to the liquid crystal display device of the present invention, by disposing the conductor pattern between the groups of the electrode terminals, it is possible to suppress the generation of static electricity on the substrate between the groups of the electrode terminals, and to suppress the end portions of the groups. It is possible to prevent electrostatic damage in the display and prevent display defects of the pixel display electrodes.

[Brief description of drawings]

FIG. 1 is a plan view showing the next step of FIG. 2 in one embodiment of the liquid crystal display device of the present invention.

FIG. 2 is a plan view showing one process of the above.

FIG. 3 is an enlarged process diagram of the vicinity of the pixel display electrode of the same.

4 is a process drawing subsequent to FIG. 3 of the same.

FIG. 5 is a process drawing next to FIG. 4 above.

FIG. 6 is an explanatory diagram showing the same operation.

FIG. 7 is a plan view showing a conventional liquid crystal display device.

FIG. 8 is an explanatory diagram showing the same operation.

[Explanation of symbols]

 2 wiring electrode 3 non-linear resistance element 6 pad portion as wiring electrode 8 pixel display electrode 10 pattern portion as conductor

Claims (1)

Claim: What is claimed is: 1. A plurality of pixel display electrodes, a metal-insulator-metal non-linear resistance element electrically connected to the plurality of pixel display electrodes, and a plurality of equal pitches. A liquid crystal display device in which an electrode terminal connected to the non-linear resistance element by a wiring electrode for each group is formed on a substrate, wherein a conductor is arranged between the group of the electrode terminals. ..