Liquid crystal display device

• US 7,733,455 B2
• Filed: 12/10/2008
• Issued: 06/08/2010
• Est. Priority Date: 09/07/1999
• Status: Expired due to Fees

• 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:
  US12/331,614
• Publication Number:
  US 20090128764A1
• Time in Patent Office: 545 Days
• Field of Search: 349/141, 349/143, 349/139, 349/138, 349/43, 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 first electrode formed of a transparent conducting layer having a plurality of slits;

a second electrode formed of a transparent conducting layer between the first electrode and the first substrate, the second electrode being formed in a planar shape without slits in the pixel areas; and

two different kinds of insulating layers including a first inorganic insulating layer and a second organic insulating layer being formed between a layer of the drain signal lines and the layer of the first electrode.

2. The liquid crystal display according to claim 1, wherein

the first electrode is a counter electrode and the second electrode is a pixel electrode;

and

the pixel areas each have a thin-film transistor connected to the drain signal line and the gate signal line and have a counter voltage signal line that feeds an electric signal to the counter electrode.

3. The liquid crystal display according to claim 2, wherein, among the drain signal line, the gate signal line, and the counter voltage signal line, the line in contact with the transparent conducting layer is made of a material containing aluminum, and the surface in contact with the transparent conducting layer has a high-melting metal layer, and the high-melting metal layer is made of any of titanium, chromium, molybdenum, tantalum, and tungsten.

4. The liquid crystal display according to claim 1, wherein part of the conducting layer of the first electrode is formed in the area superposed on the drain signal lines.

5. The liquid crystal display according to claim 1, wherein part of the conducting layer of the first electrode is formed in the area superposed on the gate signal lines.

6. The liquid crystal display according to claim 1, wherein the first inorganic insulating layer is formed between the first electrode and the second electrode, and the first inorganic insulating layer is made of silicon nitride.

7. The liquid crystal display according to claim 1, wherein the first inorqanic insulating layer and the second organic insulating layer are formed on the drain signal lines and the gate signal lines, and only the organic insulating layer is formed between the first electrode and the second electrode.

8. The liquid crystal display according to claim 1, wherein the second organic insulating layer has a dielectric constant of from 3 to 4.

9. The liquid crystal display according to claim 1, wherein the second organic insulating layer has a thickness of from 1,000 nm to 3,000 nm.

10. The liquid crystal display according to claim 1, wherein the first inorganic insulating layer and the second organic insulating layer are formed between a layer of the gate signal lines and the layer of the first electrode.

11. The liquid crystal display according to claim 1, wherein the second electrode without slits is arranged in overlapping relation with the slits of the first electrode.