Liquid crystal display device

• US 7,256,854 B2
• Filed: 12/06/2004
• Issued: 08/14/2007
• 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:
  US11/003,459
• Publication Number:
  US 20050083470A1
• Time in Patent Office: 981 Days
• Field of Search: 349/139, 349/141, 349/143, 349/144, 349/146, 349/147, 349/123
• 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 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, a counter electrode and a pixel electrode enabling formation of an electric field, and an orientation film being formed on the first substrate. The pixel electrode has a plurality of slits overlaps the counter electrode with an insulating layer therebetween. A pair of edges of the counter electrode and pixel electrode extend in parallel to the gate signal line and another pair of edges of the counter electrode and the pixel electrode extend in parallel to the drain line.

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;

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

an orientation film formed on the first substrate;

wherein the counter electrode and the pixel electrode are of planar and rectangular shape, the pixel electrode having a plurality of slits and overlapped with the counter electrode with an insulating layer being provided therebetween;

a pair of edges of the counter electrode extending in parallel to the gate signal line and another pair of edges of the counter electrode extending in parallel to the drain line;

a pair of edges of the pixel electrode of rectangular shape extending in parallel to the gate signal line and another pair of edges of the pixel electrode of rectangular shape extending in parallel to the drain line;

one of the counter voltage signal lines extends along a center of the pixel region;

the pixel electrode having a plurality of first slits and second slits, the second slits being elongated in different direction with respect to an elongation direction of the first slits, said pair of edges of the pixel electrode, and said another pair of edges of the pixel electrode; and

an initial orientation direction of the orientation film extending in parallel with one of said pair of edges and said another pair of edges of the pixel electrode.

2. The liquid crystal display device according to claim 1, wherein the initial orientation direction of the orientation film extends perpendicular to one of said pair of edges and said another pair of edges of the pixel electrode.

3. The liquid crystal display device according to claim 2, wherein the counter electrode is larger than the pixel electrode.

4. A liquid crystal display device according to claim 2, wherein the edges of the pixel electrode are arranged inside of the pixel region with respect to the edges of the counter electrode.

5. A liquid crystal display device according to claim 4, wherein the edges of the counter electrode are arranged so as to be spaced from the gate signal line and the drain signal line.

6. 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;

a counter electrode and a pixel electrode formed on the first substrate in each pixel region;

an orientation film formed on the first substrate;

the counter electrode is of planar shape, the pixel electrode is overlapped with the counter electrode with an insulating layer being provided therebetween;

wherein a first bar and a second bar of the pixel electrode are elongated so as to extend in a direction parallel to the drain signal line, the first bar being arranged near to one of the neighboring drain signal lines in the pixel region and the second bar being arranged near to another of the neighboring drain signal lines in the pixel region; and

wherein a plurality of branches of the pixel electrode extend from the first bar toward the second bar without being connected to the second bar and another plurality of branches of the pixel electrode extend from the second bar toward the first bar without being connected to the first bar, the plurality and another plurality of branches enable forming of an electric field between the pixel electrode and the counter electrode so as to enable display of an image, and at least one branch connects both the first bar and the second bar.

7. A liquid crystal display device according to claim 6, wherein an initial orientation direction of the orientation film extends perpendicular to the drain signal line, the first bar and the second bar.

8. A liquid crystal display device according to claim 7, wherein the plurality and another plurality of branches are slanted to the initial orientation direction.

9. A liquid crystal display device according claim 6, wherein the extension direction of branches from the first bar and the extension direction of branches from the second bar are different.

10. A liquid crystal display device according to claim 6, wherein the counter electrode has a rectangular shape.

11. A liquid crystal display device according to claim 10, wherein only one branch connects both the first bar and the second bar, at least two others of the plurality of branches of the pixel electrode extend from the first bar without connecting to the second bar, and at least two others of the another plurality of branches of the pixel electrode extend from the second bar without connecting to the first bar.

12. A liquid crystal display device according to claim 6, wherein the first bar of the pixel electrode is a single elongated bar at one side of the pixel region and the second bar of the pixel electrode is a single elongated bar at another side of the pixel region, and in addition to the at least one branch which connects both the first bar and the second bar, others of the plurality of branches of the pixel electrode extend from the first bar without connecting to the second bar and others of the another plurality of branches of the pixel electrode extend from the second bar without connecting to the first bar.

13. A liquid crystal display device according to claim 6, wherein the first bar and the second bar are elongated so as to extend over a length from about a middle portion of an entire length of the pixel electrode, the first bar extending from a region of the middle portion of the length of the pixel electrode to one of the upper and lower ends of the pixel electrode, and the second bar extending from a region of the middle portion of the length of the pixel electrode to an other one of the upper and lower ends of the pixel electrode.

14. 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;

a counter electrode and a pixel electrode formed on the first substrate in each pixel region;

an orientation film formed on the first substrate;

the counter electrode and the pixel electrode are of planar and rectangular shape shape, the pixel electrode overlaps with the counter electrode with an insulating layer being provided therebetween;

wherein a first bar and a second bar of the pixel electrode of rectangular shape are elongated so as to extend in parallel to the drain signal line, the first bar being arranged near to one of the neighboring drain signal lines in the pixel region and the second bar being arranged near to another of neighboring drain signal lines in the pixel region, a third bar of the pixel electrode of rectangular shape being arranged near to one of the neighboring gate signal lines in the pixel region and a fourth bar of the pixel electrode of rectangular shape being arranged near to another of the neighboring gate signal lines in the pixel region, a plurality of branches of the pixel electrode being connected between the first bar and the second bar, one of the counter voltage signal lines extends along a center of the pixel region, and the plurality of branches of the pixel electrode having a bent portion facing the one of the counter voltage signal lines.

15. A liquid crystal display device comprising:

first and second substrates with liquid crystal layer therebetween;

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

a plurality of counter voltage signal line;

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

a counter electrode and a pixel electrode formed on the first substrate in each pixel region;

an orientation film formed on the first substrate;

the counter electrode and the pixel electrode are of planar and rectangular shape, the pixel electrode overlaps with the counter electrode with an insulating layer being provided therebetween;

wherein a first bar and a second bar of the pixel electrode of rectangular shape are elongated so as to extend in parallel to the drain signal line, the first bar being arranged near to one end neighboring drain signal lines in the pixel region;

wherein a third bar of the pixel electrode of rectangular shape being arranged near to one of the neighboring gate signal lines in the pixel region and a fourth bar of the pixel electrode of rectangular shape being arranged near to another of the neighboring gate signal lines in the pixel region;

wherein a plurality of first slits and a plurality of second slits are arranged in the pixel electrode;

wherein one of the counter voltage signal lines extends along a center of the pixel region; and

wherein the first slits and the second slits are symmetrically arranged with respect to the one of the counter voltage signal lines.