Liquid crystal display device

• US 7,251,006 B2
• Filed: 12/06/2004
• 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:
  US11/003,335
• Publication Number:
  US 20050078262A1
• Time in Patent Office: 967 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
• CPC Class Codes: H05K 999/00 dummy group
• CPC Class Codes: H05K 999/99 dummy group

Abstract

A liquid crystal display device having a first transparent insulating substrate, a second transparent insulating substrate, a liquid crystal layer having liquid crystal molecules interposed between the first and second substrates, a plurality of gate bus lines and a plurality of data bus lines formed on the first substrate, wherein an area formed by two gate bus lines intersecting two data bus lines substantially defines a unit pixel. A pixel electrode made from a transparent conductor material is arranged in each unit pixel and has a plurality of upper slits parallelly arranged at a first tilt angle and a plurality of lower slits parallelly arranged at a second tilt angle and the upper slits and the lower slits are arranged in the unit pixel as an mirror image of each other and upper slits not connected to any of the lower slits.

Claims

1. A liquid crystal display device comprising:

a first transparent insulating substrate;

a second transparent insulating substrate arranged opposite to the first substrate at a distance;

a liquid crystal layer having liquid crystal molecules interposed between the first and second substrates;

a plurality of gate bus lines and a plurality of data bus lines formed on the first substrate, wherein an area formed by two gate bus lines intersecting two data bus lines substantially defines a unit pixel;

a thin film transistor formed at a selected intersection of the gate bus line and the data bus line;

a counter electrode made from a transparent conductor material disposed in each unit pixel; and

a pixel electrode also made from a transparent conductor material arranged in each unit pixel and insulated from the counter electrode of the same unit pixel to generate an electric field in the liquid crystal layer in cooperation with the counter electrode;

wherein the pixel electrode is a rectangular electrode and has a plurality of first slits parallelly arranged at a first tilt angle in the rectangular electrode and a plurality of second slits parallelly arranged at a second tilt angle in the rectangular electrode;

wherein the first slits and the second slits are arranged in the unit pixel as a mirror image of each other such that the first and second tilt angles are measured with respect to an axis that divides the first and second slits into mirror images;

wherein the first slits are connected to the second slits; and

wherein a common electrode line for providing a common signal to the counter electrode includes a portion which is formed under a connected portion of the first slits and the second slits.

2. The liquid crystal display device according to claim 1, wherein the slits of the pixel electrode in one unit pixel and the slits of the pixel electrode in an adjacent unit pixel are arranged as mirror images of each other.

3. The liquid crystal display device according to claim 1, further comprising:

a first alignment layer arranged between the first substrate and the liquid crystal layer;

a second alignment layer arranged between the liquid crystal layer and the second substrate;

a first polarizing plate arranged on the outer side of the first substrate; and

a second polarizing plate arranged on the outer side of the second substrate.

4. The liquid crystal display device according to claim 3, wherein the first and the second alignment layer are rubbed in parallel to the gate bus line.

5. The liquid crystal display device according to claim 1, wherein the common electrode line is arranged on the edge of the unit pixel adjacent the gate bus line, parallel to the gate bus line.

6. The liquid crystal display device according to claim 1, wherein the common electrode line is arranged on a line along the center of the unit pixel, parallel to the gate bus line.

7. A liquid crystal display device comprising:

a first transparent insulating substrate;

a second transparent insulating substrate arranged opposite to the first substrate at a distance;

a liquid crystal layer having liquid crystal molecules interposed between the first and second substrates;

a plurality of gate bus lines and a plurality of data bus lines formed on the first substrate, wherein an area formed by two gate bus lines intersecting two data bus lines substantially defines a unit pixel;

a thin film transistor formed at a selected intersection of the gate bus line and the data bus line;

a counter electrode made from a transparent conductor material disposed in each unit pixel; and

a pixel electrode also made from a transparent conductor material arranged in each unit pixel and insulated from the counter electrode to generate an electric field in the liquid crystal layer;

wherein the pixel electrode is a rectangular electrode and has a plurality of first slits parallelly arranged at a first tilt angle in the rectangular electrode and a plurality of second slits parallelly arranged at a second tilt angle in the rectangular electrode;

wherein the first slits and the second slits are arranged in the unit pixel as a mirror image of each other such that the tilt angle is measured with respect to the axis that divides the first and second slits into mirror images;

wherein the first slits are connected to the second slits;

wherein a common electrode line for providing common signal to the counter electrode includes a portion which is formed under a connected portion of the first slit and the second slits;

wherein a first alignment layer is arranged between the first substrate and the liquid crystal layer;

wherein a second alignment layer is arranged between the liquid crystal layer and the second substrate;

wherein a first polarizing plate is arranged on the outer side of the first substrate; and

wherein a second polarizing plate is arranged on the outer side of the second substrate.