JPH04107533A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device which has a small spot defect and excellent display quality by connecting a lower metal electrode to a data line at plural connection places. CONSTITUTION:The lower metal electrode 12 of a nonlinear resistance element 16 is connected to the data line 11 at plural connection places 11a and 11b, which are provided at a specific-distance interval to reduce the possibility that the presence of a metal residue and particulates breaking part of the data line 11 extends to the breakage of the nonlinear resistance element 16. Further, there are plural lead-out lines from the data line 11 to the lower metal electrode 12, so even if one lead-out line is destroyed by the metal residue or particulates, the other lead-out line is usable and there is no trouble as to the supply of a driving voltage to the nonlinear resistance element 16. Consequently, the spot defect is small and the display quality is improved.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) This invention uses MIM (Meta
The present invention relates to a liquid crystal display device having an l-Insulator-Metal) element.

(Prior Art) In recent years, display devices using liquid crystal displays have been used in various applications ranging from relatively simple devices such as watches, calculators, and measuring instruments to personal computers, word processors, terminal devices for office automation, and TV image displays. It has been used for displaying large amounts of information. In such large-capacity liquid crystal display devices, a matrix display multiplex driving method is generally adopted. However, with this method, due to the essential characteristics of the liquid crystal itself, there is a difference between the display area (on pixels) and the non-display area (
In terms of the contrast ratio of off-pixels, it is insufficient even when there are more than 200 scanning lines;
When performing large-scale matrix driving of approximately 00 or more lines, deterioration of contrast is fatal.

Developments to solve the drawbacks of this liquid crystal display device are actively being carried out in various places. One direction is to directly switch drive each pixel, and the switching element is, for example, a thin film transistor (hereinafter referred to as TP).
(referred to as T), MIM elements, etc. Of these, MI
The M element basically has two terminals, has a simpler structure, and is easier to manufacture than the three terminals of TPT.

FIG. 3 is a plan view showing an example of an array substrate having MIM elements. To explain this according to the manufacturing process, first, a data line 2 and an M integrated therein are placed on a glass substrate 1.
A lower metal electrode 3 of the IM element is formed. Next, the data line 2 and the lower metal electrode 3 are chemically formed by anodic oxidation using a citric acid aqueous solution or the like to form an oxide film that constitutes the insulator of the MIM element. Subsequently, the MIM element 5 is completed by forming the upper metal electrode 4 of the MIM element.

Furthermore, after this, a transparent electrode 6 for image display may be formed so as to be connected to the upper metal electrode 4.

(Problems to be Solved by the Invention) In this type of liquid crystal display device, as the display area becomes larger, fine processing becomes necessary to form MIM elements and the like. Here, when forming an MIM element, metal residue generated during etching of the upper and lower metal electrodes or various fine particles generated in a clean room may cause MIM
The probability of element destruction is increasing. When metal residue or particulates are present on the array substrate, MIM
Point defects occur not only when it adheres to the element, but also when it adheres to the lead-out part connected from the wiring electrode to the lower metal electrode of the MIM element, so the structure does not have any redundancy structure. In this case, the rate of occurrence of point defects increases.

This invention was made in view of the above-mentioned conventional circumstances.

[Structure of the Invention] (Means for Solving the Problems) The present invention arranges nonlinear resistance elements having a configuration of lower metal electrode-insulator-upper metal electrode (MIM) in an array on a substrate, a matrix array substrate in which pixel electrodes are arranged in series on nonlinear resistance elements and connected in each row or each column direction by data lines; a counter substrate in which a counter electrode is formed on the substrate; and a matrix array substrate and the counter substrate. The present invention relates to a liquid crystal display device including a liquid crystal sandwiched between a substrate and a liquid crystal. The lower metal electrode is connected to the data line at a plurality of connection points.

(Function) In this invention, since the lower metal electrode of the MIM element portion is connected to the data line at multiple points, for example, a part of the connecting portion between the lower metal electrode and the data line may be disconnected due to metal residue, fine particles, etc. In this case, no pixel point defect occurs.

As a result, the incidence of defects caused by metal residues, fine particles, etc. during the manufacturing process can be reduced compared to the conventional method.

(Example) The details of this invention will be explained below with reference to the drawings.

FIG. 1 is a diagram for explaining one embodiment of the present invention, FIG. 1(a) is a plan view showing a matrix array substrate in this embodiment, and FIG. ) of A-
A sectional view corresponding to the A-section is shown.

This embodiment will be explained according to the manufacturing process using FIG. 1. First, a first metal layer made of Ta or the like is formed on a substrate 10 made of glass by a sputtering method or the like, and then by a method such as dry etching. The data line 11 and the lower metal electrode 12 of the MIM element section are patterned.

Next, the surfaces of the data line 1 and the lower metal electrode 12 are anodized to form an anodic oxide film, thereby obtaining the insulator 13 of the MrM element portion. Subsequently, a second metal layer made of Cr, Ti, Ta, etc. is formed by sputtering or the like, and then patterned onto the upper metal electrode 14 of the MIM element portion by dry etching or the like. Next, a transparent conductive film made of ITO or the like is formed by a sputtering method, and then patterned into the pixel electrode 15 by a method such as dry etching. In this way, the nonlinear resistance elements 16 having the configuration of lower metal electrode 12 - insulator 13 - upper metal electrode 14 (MIM) are arranged in an array on the substrate 10, and the pixel electrodes 15 are arranged in series with the nonlinear resistance elements 16. A matrix array substrate 17 is obtained in which the data lines 11 connect each row or each column.

Then, an alignment film made of polyimide resin is further coated and baked on the surface of the matrix array substrate 17 on which the nonlinear resistance elements 16 are formed, and then rubbed, thereby regulating the alignment direction of the liquid crystal molecules. Separately, a striped counter electrode 19 made of ITO is formed on a substrate 18 made of glass, for example, so as to overlap the pixel electrode 15 through the liquid crystal 20 in a direction perpendicular to the data line 11, and is made of polyimide resin. A counter substrate 21 is prepared in which the orientation direction of liquid crystal molecules is regulated by an alignment film and rubbing. And LCD 2
The liquid crystal 20 is injected into the matrix array substrate 17 and the counter substrate 21 with a gap of 5 to 20 μm maintained so that the long axis direction of the 0 molecules is twisted by about 90° between the matrix array substrate 17 and the counter substrate 21.

In this embodiment, the lower metal electrode 1 of the nonlinear resistance element 16 is
2, the data line 11 and a plurality of connection points 11a, llb
Since these connection points 11a and llb are spaced apart from each other by a predetermined distance, the presence of metal residues and fine particles that could destroy a part of the data line 11 can be prevented from forming on the nonlinear resistance element 16. This reduces the possibility of damage.

In addition, since there are multiple lead wires from the data line 11 to the lower metal electrode 12, even if one of the lead wires is destroyed by metal residue and fine particles, the other lead wire can be used, resulting in non-linear There is no problem in supplying the drive voltage to the resistance element 16.

FIG. 2 is a plan view showing a matrix array substrate in another embodiment of the invention, and parts corresponding to those in FIG. 1 are given the same reference numerals. In FIG. 2, the pixel electrode 15 is divided into two parts having a trapezoidal shape (FIG. 2(a)) or a rectangular shape (FIG. 2(b)). Pixel electrode 1 with divided extraction part
It has a structure that surrounds one side of 5. These embodiments not only have the same effect as the embodiment shown in FIG. 1, but also have the same effect as the embodiment shown in FIG. This is superior to the other embodiments.

[Effects of the Invention] In the present invention, since the lower metal electrode of the MIM element portion is connected to the data line at a plurality of locations, a liquid crystal display device with few point defects and good display quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view and a sectional view showing an embodiment of the present invention;
FIG. 2 is a plan view showing a matrix array substrate according to another embodiment of the present invention, and FIG. 3 is a plan view showing an example of a pixel portion of a conventional matrix array substrate. 10.18...Substrate. 11... Data lines 11a, llb... Connection point 12... Lower metal electrode, 13... Insulator 14.
...Top metal electrode, 15...Pixel electrode 16...
Nonlinear resistance element 17... Matrix array substrate 19... Counter electrode, 20... Liquid crystal 21...
・Counter substrate 17 Matrix 7 7'1111 (a) Figure 1 (a) Figure Figure

Claims (1)

[Claims] Lower metal electrode-insulator-upper metal electrode (MI
A matrix array substrate in which nonlinear resistance elements having the configuration M) are arranged in an array, pixel electrodes are arranged in series with the nonlinear resistance elements, and each row or column direction is connected by a data line; A liquid crystal display device comprising a counter substrate formed with a counter electrode, and a liquid crystal sandwiched between the matrix array substrate and the counter substrate,
A liquid crystal display device, wherein the lower metal electrode is connected to the data line at a plurality of connection points.