JPS6125125A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To easily align edges of electrodes and to improve a display image by laminating a metallic electrode and a transparent electrode on a substrate in three-layer structure, and forming those transparent electrode and metallic electrode of this three-layer structure with a pattern at a time. CONSTITUTION:Transparent electrodes 2 forming picture elements are arrayed on the transparent substrate 1 and connected by metallic electrodes 3 in three- layer structure at a time by employing pattern formation. Thus, the metallic electrodes 3 and transparent electrodes 2 are formed in sandwich structure with the pattern at a time to easily align their edges, thereby improving the display image. The restrictions of the material of the metallic electrodes depending upon the reaction between the liquid crystal and the metallic electrodes 3 and the adhesive strength of the metallic electrodes 3 to the substrate are eliminated and almost all kinds of metal having good conductivity are usable. Further, metallic wiring resistance is small, which is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a liquid crystal display element used in liquid crystal televisions and the like.

<Prior Art> FIGS. 5 and 6 show electrode patterns using metal wiring for achieving a low resistance film in a liquid crystal display element.

Transparent electrodes 2 forming pixels are arranged on a glass substrate 1, and metal electrodes 3 connecting the respective transparent electrodes 2 are formed. The metal electrode 3 is formed on the end portion 2a of the transparent electrode 2 with a width of 20 to 50 μm. Metal electrode 3
The width is selected so as not to impair the display image of the liquid crystal display element and to reduce the electrical resistance of the metal wiring.

A method for forming the above-mentioned electrode pattern will be explained.

First, metal is formed on the entire surface of the glass substrate 1, and a pattern of the metal electrode 3 is formed by photoetching, or a photoresist film is first patterned by a lift-off method, and then metal is formed on it. By removing the photoresist film, a pattern of the metal electrode 3 is formed. Thereafter, a transparent electrode 2 is formed on the entire surface by a sputtering method or an electron beam heating type electron impact method, and a pattern of the transparent electrode 2 is formed by photoetching.

However, in the above method, since the pattern of the metal electrode 3 and the pattern of the transparent electrode 2 are formed separately, it is difficult to match the edges of the metal electrode 3 and the transparent electrode 2. A pattern shift as shown occurs. 7th
In Figures (a) and 8(a), the metal electrode 3 is located inside the edge of the transparent electrode 2, so the pixel area is divided, which has the disadvantage of reducing the size of the pixel. .

Figures 7 (b) and 8 (b) are appropriate cases.

In Figures 7 (c) and 8 (c), the metal electrode 3 protrudes outward from the edge of the transparent electrode 2, and there is a deformation of the pixel size, but since it is not divided, it is not visible in the display. Although there is no effect, there is a problem that depending on the material of the metal, a reaction may occur with the liquid crystal. Therefore, it is necessary to match the edges of the metal electrode and the transparent electrode, but this conventionally required a complicated process.

In addition, in the method described above, since the metal electrode 3 is formed directly on the glass substrate 1, if the material of the metal electrode 3 is a metal that has poor adhesion to glass, the metal electrode will gradually be formed during long-term use. It peels off and the pull-out resistance value changes. Therefore, it was necessary to form a metal with good adhesion to glass on the side of the metal electrode 3 in contact with the galley substrate 1, or to form the entire metal electrode 3 from a metal with good adhesion to glass. . Generally, the lower layer of the metal electrode 3 is Cr2, which has good adhesion to glass, and the upper layer is ALI, or the entire metal electrode 3 is formed of a Ni--Cr alloy. However, when stacking Cr and Au, there is no problem with adhesion and electrical conductivity, but the cost increases, and when the whole is made of Ni-Cr alloy, the electrical conductivity is poor and the drawing resistance is low. There was a problem that the value was large.

Table 1 shows the adhesion of various metals to glass.

Table 1 ◎: Very strong, ○: Strong, △: Inferior. ×: Weak As mentioned above, in the past, the patterns of the metal electrode and transparent electrode were formed separately, resulting in irregularities in the pattern edges, and due to the adhesion and electrical conductivity of the metal electrode to the glass substrate. There was a problem with material limitations.

<Object of the invention> The present invention was made in view of the above circumstances, and its object is to create a structure in which a metal electrode is sandwiched between transparent electrodes, so that pattern formation of three layers of electrodes can be performed at one time. An object of the present invention is to provide a liquid crystal display element.

<Structure of the Invention> In the present invention, in a liquid crystal display element formed by arranging a plurality of transparent electrodes forming pixels on a transparent substrate and connecting each transparent electrode with a metal electrode, on the substrate, The transparent electrode has a three-layer structure in which metal electrodes are sandwiched between upper and lower sides, and the transparent electrode and metal electrode of this three-layer structure are characterized in that they are patterned at the same time.

<Example> An embodiment of the present invention will be described below.

1 and 2 show the structure of a liquid crystal display element.

A plurality of transparent electrodes 2 forming pixels are arranged on a transparent substrate 1 made of glass or the like, and metal electrodes 3 connecting the respective transparent electrodes 2 are formed. The metal electrode 3 is
At the end 2a of the transparent electrode 2, the top N2b of the transparent electrode 2
and the lower layer 2C are sandwiched between the upper and lower layers. That is, transparent electrode 2b, metal electrode 3. The transparent electrode 2C is formed in a three-layer structure, and therefore the metal electrode 3 is formed on the substrate 1 via the transparent electrode 2C.

Figures 3 and 4 show the state of the manufacturing process of a liquid crystal display element.

As shown in FIG. 3(a) and FIG. 4(a), first, a transparent electrode 2c/ is formed on the entire surface of the substrate l, and then a metal electrode 3' is formed on this transparent electrode 20'. form a pattern. The metal electrode 3' is patterned by photo-etching or lift-off. In this case, with respect to the pattern of the completed transparent electrode 2 shown by the broken line, the metal electrode 3' overlaps the end 2a of the transparent electrode 2 and partially overlaps the gap A between the adjacent transparent electrodes 2, 2. , a pattern of metal electrode 3' is formed. Generally, the gap A between the transparent electrodes 2, 2 has a width of 40 to 50 μm, and the width of the portion of the metal electrode 3' that overlaps with the transparent electrode 2 can be considered only from the electrical resistance. It is not necessary to perform positioning with high precision.

Next, a transparent electrode 2b' is formed on the entire surface of the transparent electrode 20' and metal electrode 3'. After that, the transparent electrode 2b'
, 2c' and metal electrode 3' are patterned at once,
As shown in FIGS. 3(b) and 4(b), transparent electrodes 2 and metal electrodes 3 forming pixels are formed on the substrate 1. As a method for forming this pattern, a wet photoetching method is preferable. Since the metal electrode is sandwiched between the transparent electrodes, when the transparent electrode is chemically etched, etching progresses from above and below the metal electrode, and unnecessary portions of the metal electrode are removed to form a pattern. In this case, since the transparent electrodes 2b, 2c and the metal electrode 3 are patterned by etching at the same time,
At the edge portion e of the pixel, the edges of the transparent electrodes 2b, 2c and the metal electrode 3 coincide with each other.

Next, an example of the manufacturing method will be shown.

■ Glass base i: #7740 Fusion Vilex 1.1 transparent electrode: In2Oa +SnO2 (5wt%) 30
0-500 people Metal electrode: 41300 people Photoresist: ^e-OFPn-77EIn 20
3-OFPR-77E Etching solution: A# at 25°C (Fe2C1a: HCA! = 1: 1 mo
l%In203am 30°C Positioning accuracy of metal electrode to pixel: ±20μ Glass substrate: #7740 Fusion Pyrex 1
．． 1 as transparent electrode: In2O3+Sn02, (5HL%)
300-500 people Metal electrode: Ni 300 people Photoresist: Ni-0FPR-77EIn 2
0 a-OFPR-77E Etching solution: In20 using the inversion etching method using the Ni-lift-off method Positioning accuracy of the metal electrode with respect to the pixel: ±20μ <Effects of the Invention> As explained above, in the present invention, the substrate The transparent electrode has a three-layer structure in which the metal electrode is sandwiched between the upper Y,
Since the transparent electrode and metal electrode of this three-layer structure are patterned at the same time, the edges of the metal electrode and the transparent electrode can be easily matched, which not only improves the display image but also improves the liquid crystal display. There are no restrictions on the material of the metal electrode due to the reaction with the metal electrode and the adhesion of the metal electrode to the substrate, and almost any metal can be used as long as it has good conductivity. Furthermore, the metal wiring resistance is smaller than that of the conventional two-layer structure of a transparent electrode and a metal electrode.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of a liquid crystal display element according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a front view showing the state of the manufacturing process of the liquid crystal display element according to the present invention. Figure 4 is the third
5 is a front view showing a conventional example of a liquid crystal display element; FIG. 6 is a plan view of FIG. 5; FIG. 7 is a front view showing another conventional example of a liquid crystal display element; The figure is a plan view of FIG. 7. 1 - Substrate 2 - Transparent electrode 3 - Metal electrode

Claims (1)

[Claims] In a liquid crystal display element formed by arranging a plurality of transparent electrodes forming pixels on a transparent substrate and connecting each transparent electrode with a metal electrode, the transparent electrodes sandwich the metal electrodes above and below on the substrate. It has a three-layer structure, and these three
A liquid crystal display element characterized by patterning a layered transparent electrode and a metal electrode at the same time.