Liquid crystal display device

• US 7,705,949 B2
• Filed: 12/10/2008
• Issued: 04/27/2010
• Est. Priority Date: 09/07/1999
• Status: Expired due to Fees

• Current Assignee: Japan Display Incorporated
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakayoshi, Yoshiaki, Ono, Kikuo, Yamamoto, Tsunenori, Yoneya, Makoto, Hirakata, Junichi
• Primary Examiner(s): Duong; Thoi V
• Application Number:
  US12/331,631
• Publication Number:
  US 20090135326A1
• Time in Patent Office: 503 Days
• Field of Search: 349/141, 349/139, 349/138, 349/43, 349/143, 349/38
• US Class Current: 349/143
• 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
• CPC Class Codes: H05K 999/00 dummy group
• CPC Class Codes: H05K 999/99 dummy group

Abstract

A liquid crystal display includes a pair of transparent substrates opposed to each other with liquid crystal therebetween, one of the pair of transparent substrates having a plurality of drain signal lines and a plurality of gate signal lines, and a plurality of pixel areas defined by the drain signal lines and the gate signal lines. The pixel areas includes a pixel electrode formed of a transparent electrode having a plurality of slits including a slit opened in a first direction and a slit opened in a second direction, and a counter electrode formed of a transparent electrode disposed between the transparent electrode of the pixel electrode having the plurality of slits and the one substrate.

Claims

1. A liquid crystal display comprising:

a first substrate and a second substrate opposed to each other with liquid crystal therebetween, the first substrate having a plurality of drain signal lines and a plurality of gate signal lines; and

a plurality of pixel areas defined by the drain signal lines and the gate signal lines;

the pixel areas having;

a thin film transistor;

a first electrode formed of a transparent conducting layer having a plurality of slits;

a second electrode formed of a transparent conducting layer which forms an electric field for operating a liquid crystal for cooperating with the first electrode, the second electrode having a planar shape without slits; and

the gate signal line is formed on the first substrate, a first insulating film is formed on the gate signal line, the thin film transistor is formed on the first insulating film, a second insulating film and a third insulating film are formed on the thin film transistor, the second electrode is formed on the thin film transistor; and

one of the second insulating film and the third insulating film is formed between the first electrode and the second electrode.

2. The liquid crystal display according to claim 1, wherein the first electrode is a counter electrode, the second electrode is a pixel electrode.

3. The liquid crystal display according to claim 1, wherein one of the second insulating film and the third insulating film is an organic insulating film, and another of the second insulating film and the third insulating film is an inorganic insulating film.

4. The liquid crystal display according to claim 1, wherein the second insulating film and the third insulating film are formed on the drain signal line.

5. The liquid crystal display according to claim 4, wherein the first electrode is formed on the drain signal line.

6. The liquid crystal display according to claim 5, wherein an overlap region is formed between a peripheral portion of the first electrode on the drain signal line and the second electrode.

7. The liquid crystal display according to claim 1, wherein the second electrode and the source electrode are formed in a different layer, the source electrode is connected to the second electrode through a contact hole.