Liquid crystal display cell

• US 4,297,004 A
• Filed: 09/17/1979
• Issued: 10/27/1981
• Est. Priority Date: 09/20/1978
• Status: Expired due to Term

• Current Assignee: Technical Research of Citizen Watch Company Limited
• Original Assignee: Technical Research of Citizen Watch Company Limited
• Inventors: Nishimura, Katsuo, Nanya, Takanori
• Primary Examiner(s): Bauer, Edward S.
• Application Number:
  US06/076,189
• Time in Patent Office: 771 Days
• Field of Search: 350/334, 350/336, 350/343, 350/339 R, 350/338
• US Class Current: 349/138
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals

Abstract

In the lead electrodes which connect to the display electrodes of a liquid crystal display device having lead electrodes which are of extremely narrow width and are spaced very closely together, the resistance of each lead electrode is reduced by means of a multi-layer structure of relatively low resistance, and leakage current is prevented from flowing between adjacent lead electrodes by providing a transparent insulating layer over and between the lead electrodes, thereby eliminating the deleterious effects upon display appearance of a high lead electrode resistance and leakage currents between lead electrodes.

Claims

1. In a liquid crystal display cell composed of two transparent supporting substrates arranged parallel to one another, sealed together peripherally to form an enclosed chamber containing a liquid crystal material, and having a transparent display electrode formed on an inner face of at least one of said transparent supporting substrates composed of a thin film of an electrically conductive substance and a lead electrode provided on said inner substrate face for providing electrical connection between said transparent display electrode and external drive means, the improvement comprising a multi-layer construction for said lead electrode for thereby reducing the electrical resistance thereof, said multi-layer lead electrode construction comprising a metallic electrode layer of a metallic substance formed on said inner substrate face and a lead electrode layer formed over said metallic electrode layer, said lead electrode layer being formed integrally with said display electrode and having a width which is substantially equal to the width of said metallic electrode layer, measured in a direction parallel to the substrate plane.

2. The improvement according to claim 1, in which said metallic electrode layer is composed of a first layer of chromium deposited directly on said inner substrate face and a second layer of gold formed over said layer of chromium.

3. The improvement according to claim 2, in which said layer of chromium is formed substantially over the entirety of said inner substrate face.

4. The improvement according to claim 1, in which said lead electrode has a width of less than 30 microns.

5. The improvement according to claim 1, in which a plurality of said lead electrodes are provided on said inner substrate face and situated closely adjacent to one another, and further comprising a transparent insulating layer formed over and between said plurality of lead electrodes.

6. The improvement according to claim 5, in which said transparent insulating layer is formed from a substance selected from a group including Al₂ O₃, SiO₂, and Si₃ N₄.

7. The improvement according to claim 5, and further comprising a transparent coating layer formed between said transparent insulating layer and said plurality of lead electrodes.

8. The improvement according the claim 7, in which said transparent coating layer is composed of SiO₂.

9. The improvement according to claim 6, in which said transparent insulating layer has a thickness which is in the range of 0.1 to 3 microns.

10. The improvement according to claim 8, in which said transparent coating layer has a thickness which is in the range of 200 to 800 Angstroms.