Liquid-crystal display device employing a common electrode consisting of interconnected common electrode sections

• US 4,869,576 A
• Filed: 07/29/1988
• Issued: 09/26/1989
• Est. Priority Date: 10/04/1985
• Status: Expired due to Term

• Current Assignee: TPO Hong Kong Holding Limited (InnoLux Corporation)
• Original Assignee: Hosiden Electronics Co. Ltd. (Hosiden Corporation)
• Inventors: Matsushita, Yasuhiro, Ukai, Yasuhiro, Aoki, Shigeo
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US07/227,033
• Time in Patent Office: 424 Days
• Field of Search: 350/339 R, 350/339 F, 350/334, 350/336, 350/333, 340/784, 357/23.7, 357/4, 357/45
• US Class Current: 349/143
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body

Abstract

A liquid-crystal cell is formed with first and second transparent substrates opposing each other and a liquid crystal sealed therebetween. A plurality of display electrodes are formed in a matrix arrangement with rows and columns on the inner surface of said first transparent substrate. Gate bus lines are formed on the first transparent substrate along the respective rows of display electrodes. Source bus lines are formed on the first transparent substrate along the respective columns of display electrodes. Thin-film transistors are formed on the first transparent substrate at the intersections of a gate and source bus lines. The thin-film transistors each have a gate electrode connected to the associated gate bus line, a source electrode connected to the associated source bus line and the drain electrode connected to the corresponding display electrode. A common electrode is formed on the second transparent substrate such that it faces the display electrodes. The opposed sides of the source and drain electrodes of each thin-film transistor are constituted by tapered surfaces with the distance therebetween progressively decreased as they approach the first transparent substrate. Ohmic contact layers are formed on these tapered surfaces. A semiconductor of each thin-film transistor is formed over the source and drain electrodes via the ohmic contact layers.

Claims

1. A liquid-crystal display device comprising:

a liquid-crystal cell including first and second transparent substrates opposing each other and a liquid crystal sealed therebetween;

a plurality of transparent display electrodes formed in a matrix arrangement with rows and columns on the inner surface of said first transparent substrate;

a plurality of gate bus lines formed on said first transparent substrate along the respective rows of said display electrodes;

a plurality of source bus lines formed on said first transparent substrate along the respective columns of said display electrodes;

a plurality of thin-film transistors provided at intersections of said source and gate bus lines and each having a drain electrode connected to the corresponding display electrode, a source electrode connected to the associated source bus line and a gate electrode connected to the associated gate bus line; and

a common electrode consisting of common electrode sections having substantially the same size and shape as said respective display electrodes and facing therewith, each of said common electrode sections having four sides, adjacent ones of said common electrode sections being connected together by a connecting section on each of said four sides of each said common electrode section whereby said common electrode sections are connected to one another in both row and column directions, said common electrode sections and said connecting sections being formed on said second transparent substrate.

2. The liquid-crystal display device according to claim 1, which further comprises color filters formed on said second transparent substrate such as to face said respective display electrodes, said color filters consisting of three different color filters distributed substantially uniformly.

3. The liquid-crystal display device according to claim 2, which further comprises a black filter formed to fill the gap between adjacent ones of said color filters.