Liquid crystal display device with control capacitors for gray scale

• US 5,321,535 A
• Filed: 05/27/1993
• Issued: 06/14/1994
• Est. Priority Date: 07/23/1990
• Status: Expired due to Term

• Current Assignee: TPO Hong Kong Holding Limited (InnoLux Corporation)
• Original Assignee: Hosiden Corporation
• Inventors: Inada, Toshiya, Ukai, Yasuhiro, Sunata, Tomihisa
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/067,975
• Time in Patent Office: 383 Days
• Field of Search: 359/54, 359/55, 359/57, 359/59, 359/79, 359/87, 345/87, 345/89, 345/92, 345/152
• US Class Current: 349/85
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/134354 the sub-pixels being capacitively coupled
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 2203/30 Gray scale

Abstract

Each pixel electrode of a liquid crystal display device is divided into a plurality of subpixel electrodes, which are separated by a gap from each other, and a control capacitor electrode is provided opposite at least one of the subpixel electrodes through a first insulating film. The control capacitor electrode has a region extending the entire length of the gap so that a drive voltage can be applied to liquid crystal in the gap. The control capacitor electrode forms a control capacitor connected in series with a liquid crystal capacitor formed by the at least one subpixel electrode between it and a common electrode corresponding thereto. An additional capacitor electrode, which is opposite the at least one subpixel electrode through a second insulating film, is formed, by which is formed an additional capacitor equivalently in parallel to the liquid crystal capacitor.

Claims

1. A liquid crystal display device comprising at least one subpixel electrode occupying a part of a region defined by a pixel, said subpixel electrode being disposed on an insulating film on a first base plate in opposing relation to a common electrode on a second base plate across liquid crystal, a control capacitor electrode partly opposite said at least one subpixel electrode being provided through said insulating film to form a control capacitor connected in series with a liquid crystal capacitor formed between said at least one subpixel electrode and said common electrode, means for applying a drive voltage across said control capacitor electrode and said common electrode, and an additional capacitor electrode formed in the same plane as said control capacitor electrode in opposing relation to said at least one subpixel electrode through said insulating film to form an additional capacitor equivalently in parallel to said liquid crystal capacitor.