Active matrix liquid crystal display device having capacitive electrodes opposite the source buses

• US 4,787,712 A
• Filed: 01/04/1988
• Issued: 11/29/1988
• Est. Priority Date: 01/16/1987
• Status: Expired due to Term

• Current Assignee: TPO Hong Kong Holding Limited (InnoLux Corporation)
• Original Assignee: Hosiden Electronics Co. Ltd. (Hosiden Corporation)
• Inventors: Ukai, Yasuhiro, Yukawa, Teizo, Sunata, Tomihisa
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Gallivan, Richard
• Application Number:
  US07/140,681
• Time in Patent Office: 330 Days
• Field of Search: 350/333, 350/336, 350/339 R
• US Class Current: 349/38
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence

Abstract

Liquid crystal is sealed in between a pair of opposed first and second transparent substrates, picture element electrodes, gate buses, and source buses are formed on the first transparent substrate, and thin film transistors are each disposed at one of the intersections of the source and gate buses, thereby constituting an active matrix liquid crystal display element. On the first transparent substrate there are provided capacitive electrodes respectively opposite the source buses, with an insulating layer interposed therebetween, and the capacitive electrodes are connected to a common potential point.

Claims

1. An active matrix liquid crystal display device in which liquid crystal is sealed in between a pair of opposed first and second transparent substrates, picture element electrodes are arranged in a matrix form on the inner surface of the first transparent substrate, gate buses are each disposed along one of the row arrangements of the picture element electrodes, source buses are each disposed along one of the column arrangements of the picture element electrodes, a thin film transistor is provided at each intersection of the gate and source buses, and the gate, source and drain of the thin film transistor are connected to the gate bus, the source bus and the picture element electrode corresponding to the thin film transistor, whereby a liquid crystal display element is constituted;

wherein a plurality of outputs of a source driver are connected to the source buses, respectively;

capacitive electrodes are provided on the first transparent substrate in opposing relation to the source buses, respectively, with an insulating layer sandwiched therebetween; and

the capacitive electrodes are connected to a common potential point to form a desired electrostatic capacitance between each of the capacitive electrode and the corresponding source bus.

2. The device of claim 1, wherein a common potential point connection line is provided along the direction of arrangement of the capacitive electrodes, for connecting them to the common potential point.

3. The device of claim 1, wherein the capacitive electrodes are disposed closer to the first transparent substrate than the source buses.

4. The device of claim 3, wherein a light shielding layer of metal is disposed opposite the thin film transistors, the light shielding layer and the capacitive electrodes are formed simultaneously, and an insulating layer between the light shielding layer and the thin film transistors and the insulating layer are formed simultaneously.

5. The device of claim 1, wherein the capacitive electrodes are disposed on the side opposite from the first transparent substrate relative to the source buses.

6. The device of claim 5, wherein the insulating layer is formed simultaneously with gate insulating films of the thin film transistors and the capacitive electrodes are formed simultaneously with gate electrodes of the thin film transistors.