LIQUID CRYSTAL DISPLAY DEVICE

• US 20100201933A1
• Filed: 02/05/2010
• Published: 08/12/2010
• Est. Priority Date: 02/09/2009
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Matsui, Chikae, Kunimatsu, Noboru, SONODA, Hidehiro
• Granted Patent: US 8,958,042 B2
• Time in Patent Office: Days
• US Class Current: 349/141
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• 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 1/13398 Spacer materials; Spacer properties
• 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 1/136286 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

Abstract

A liquid crystal display device of the invention can, when a liquid crystal panel receives a pressing force from the outside, prevent the displacement of columnar spacers which are formed over a counter substrate for defining a distance between the counter substrate and a TFT substrate in the direction parallel to the substrate. In a case where the TFT substrate or the counter substrate receives a pressing force from the outside, when the columnar spacers which define the distance between the TFT substrate and the counter substrate are displaced in one or more directions, the alignment disorder of liquid crystal molecules occurs or an alignment film is shaved so that leaking of light occurs due to shaved chips of the alignment film and hence, contrast of an image is lowered. Projections are formed on a TFT substrate side by making use of bus electrodes provided for preventing lowering of a voltage of counter electrodes. When the TFT substrate or the counter substrate receives a pressing force from the outside, the projections bite into a distal end of the columnar spacer so that the displacement of the columnar spacer in one or more directions can be prevented.

Claims

1. A liquid crystal display device comprising:

a TFT substrate on which a pixel is formed in each of regions surrounded by scanning lines which extend in the first direction and are arranged parallel to each other in the second direction and video signal lines which extend in the second direction and are arranged parallel to each other in the first direction;

a counter substrate which is arranged to face the TFT substrate in an opposed manner; and

a liquid crystal layer which is sandwiched between the TFT substrate and the counter substrate, wherein

a pixel electrode formed in a planar shape and a counter electrode formed in a comb-teeth shape on the pixel electrode by way of an insulation film are arranged in the pixel,

columnar spacers which define a distance between the TFT substrate and the counter substrate are formed over the counter substrate,

a bus electrode made of metal which extends in the first direction and is connected with the counter electrode is formed over the scanning line formed over the TFT substrate, and

a distal end of the columnar spacer faces the bus electrode in an opposed manner, and a width of the bus electrode is 3 μ

m or less.

2. A liquid crystal display device according to claim 1, wherein the bus electrode extends in the second direction and has a cruciform shape at an intersection of the scanning line and the video signal line, and a distal end of the columnar spacer faces the bus electrode having the cruciform shape in an opposed manner.

3. A liquid crystal display device according to claim 1, wherein island-shape projections which are formed using the same material as the bus electrode are formed in the vicinity of intersections of the scanning lines and the video signal lines while sandwiching the bus electrode between two neighboring projections,

a width of the island-shape projection is 3 μ

m or less, and

the columnar spacer faces either one of the bus electrode and the island-shape projection in an opposed manner.

4. A liquid crystal display device comprising:

a TFT substrate on which a pixel is formed in each of regions surrounded by scanning lines which extend in the first direction and are arranged parallel to each other in the second direction and video signal lines which extend in the second direction and are arranged parallel to each other in the first direction;

a counter substrate which is arranged to face the TFT substrate in an opposed manner; and

a liquid crystal layer which is sandwiched between the TFT substrate and the counter substrate, wherein

a counter electrode formed in a planar shape and a pixel electrode formed in a comb-teeth shape on the counter electrode by way of an insulation film are arranged in the pixel,

columnar spacers which define a distance between the TFT substrate and the counter substrate are formed over the counter substrate,

projections which are formed using the same material as the pixel electrodes are formed over the scanning line formed over the TFT substrate, and

a distal end of the columnar spacer faces the projection in an opposed manner, and a width of the projection is 3 μ

m or less.

5. A liquid crystal display device according to claim 4, wherein the projection extends in the first direction and the second direction thus forming a cruciform shape at an intersection of the scanning line and the video signal line, and a distal end of the columnar spacer faces the projection having a cruciform shape in an opposed manner.

6. A liquid crystal display device according to claim 4, wherein a plurality of projections are formed in an inland shape at an intersection of the scanning line and the video signal line.

7. A liquid crystal display device comprising:

a TFT substrate on which a pixel electrode is formed in each of regions surrounded by scanning lines which extend in the first direction and are arranged parallel to each other in the second direction and video signal lines which extend in the second direction and are arranged parallel to each other in the first direction;

a counter substrate which is arranged to face the TFT substrate in an opposed manner; and

a liquid crystal layer which is sandwiched between the TFT substrate and the counter substrate, wherein

a counter electrode is formed over the counter substrate in a state where the counter electrode faces the pixel electrodes formed on the TFT substrate in an opposed manner,

columnar spacers which define a distance between the TFT substrate and the counter substrate are formed over the counter substrate,

projections which are formed using the same material as the pixel electrodes are formed over the scanning lines of the TFT substrate, and

a distal end of the columnar spacer faces the projection in an opposed manner, and a width of the projection is 3 μ

m or less.

8. A liquid crystal display device according to claim 7, wherein the projection extends in the first direction and the second direction thus forming a cruciform shape at an intersection of the scanning line and the video signal line, and the distal end of the columnar spacer faces the projection having the cruciform shape in an opposed manner.

9. A liquid crystal display device according to claim 7, wherein a plurality of island-shaped projections are formed at an intersection of the scanning line and the video signal line.