Liquid crystal display device comprising two counter voltage signal lines having two branches in each pixel region

• US 7,251,005 B2
• Filed: 12/03/2004
• Issued: 07/31/2007
• Est. Priority Date: 09/07/1999
• Status: Expired due to Term

• Current Assignee: Japan Display Incorporated
• Original Assignee: Hitachi, Ltd.
• Inventors: Ono, Kikuo, Yamamoto, Tsunenori, Yoneya, Makoto, Nakayoshi, Yoshiaki, Hirakata, Junichi
• Primary Examiner(s): Duong; Thoi V.
• Application Number:
  US11/002,896
• Publication Number:
  US 20050078261A1
• Time in Patent Office: 970 Days
• Field of Search: 349/141, 349/143, 349/139, 349/147
• US Class Current: 349/141
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio

Abstract

A liquid crystal display device having first and second substrates with a liquid crystal layer therebetween, a plurality of gate signal lines and a plurality of drain signal lines, a plurality of counter voltage signal lines, a plurality of pixel regions defined by neighboring gate signal lines and drain signal lines. and a counter electrode and a pixel electrode formed on the first substrate in each pixel region so as to enable an electric field to be formed therebetween. The counter electrode is of planar shape and made of a transparent conductor. The counter voltage signal line is made of metal and has a branch in each pixel region with the counter electrode being directly connected to the branch.

Claims

1. A liquid crystal display device comprising:

first and second substrates with a liquid crystal layer therebetween;

a plurality of gate signal lines and a plurality of drain signal lines;

a plurality of counter voltage signal lines;

a plurality of pixel regions defined by neighboring gate signal lines and drain signal lines; and

a counter electrode and a pixel electrode formed on the first substrate in each pixel region so as to enable an electric field to be formed therebetween;

wherein the counter electrode is of planar shape and made of a transparent conductor; and

wherein one of the pixel regions includes two of the counter voltage signal lines, each of the counter voltage signal lines being made of metal and having two branches in each pixel region, the counter electrode being directly connected to the counter voltage signal lines and the branches.

2. A liquid crystal display device according to claim 1, wherein each of the branches is provided in a layer which is above a layer of the counter electrode.

3. A liquid crystal display device according to claim 2, wherein a width of each of the branches is larger than a thickness of the counter electrode.

4. A liquid crystal display device according to claim 1, wherein each of the branches extends in parallel to the drain signal line.

5. A liquid crystal display device according to claim 1, wherein a thickness of a portion of each of the branches is larger than a thickness of the counter electrode.

6. A liquid crystal display device according to claim 5, wherein a thickness of each of the branches in a portion in nonoverlapping relation with the counter electrode is larger than a thickness of the counter electrode.

7. A liquid crystal display device according to claim 1, wherein edges of the counter electrode are covered by the counter voltage signal lines and the branches.