Liquid crystal display substrate and liquid crystal display device

• US 9,097,954 B2
• Filed: 06/07/2013
• Issued: 08/04/2015
• Est. Priority Date: 12/10/2010
• Status: Expired due to Fees

• Current Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Original Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Inventors: Sakamoto, Taro, Fukuyoshi, Kenzo
• Primary Examiner(s): Glick, Edward
• Assistant Examiner(s): Liu, Shan
• Application Number:
  US13/912,958
• Publication Number:
  US 20130271707A1
• Time in Patent Office: 788 Days
• Field of Search: 349/141, 349/106, 349/139
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/133742 for homeotropic alignment
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134318 having a patterned common electrode
• CPC Class Codes: G02F 1/134381 Hybrid switching mode, i.e. for applying an electric field with components parallel and orthogonal to the substrates
• CPC Class Codes: G02F 1/13712 the liquid crystal having negative dielectric anisotropy
• CPC Class Codes: G02F 1/139 based on orientation effects in which the liquid crystal remains transparent
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio

Abstract

In a liquid crystal display substrate, the array substrate includes comb-shaped first and second electrodes. The counter substrate faces the array substrate via a liquid crystal layer and includes a comb-shaped third electrode. In a cross-section perpendicular to the first through third longitudinal directions, comb teeth of the first and second electrodes have a positional relationship in which one is shifted from the other in a first horizontal direction. Comb teeth of the first and third electrodes have a positional relationship in which one is shifted from the other in a second horizontal direction which is opposite to the first horizontal direction.

Claims

1. A liquid crystal display device comprising:

an array substrate that comprises a comb-shaped first electrode, which is a pixel electrode, an insulating layer, and a comb-shaped second electrode arranged in this order, a first longitudinal direction of comb teeth of the comb-shaped first electrode and a second longitudinal direction of comb teeth of the comb-shaped second electrode being parallel to each other, and the array substrate being partitioned into pixel units or sub-pixel units; and

a counter substrate that faces the array substrate via a liquid crystal layer and comprises a comb-shaped third electrode, the first longitudinal direction and a third longitudinal direction of comb teeth of the comb-shaped third electrode being parallel to each other, and the counter substrate being partitioned into the pixel units or the sub-pixel units,

wherein the liquid crystal layer comprises liquid crystals that have negative dielectric constant anisotropy, and are vertically aligned in an initial state,

in a cross-section perpendicular to the first through third longitudinal directions and parallel to a thickness direction of the liquid crystal layer, the first comb-shaped electrode and the third comb-shaped electrode are disposed in a state of facing one another via the liquid crystal layer, and the first through third comb-shaped electrodes are formed at respective positions symmetrical about a central axis in a cross-sectional view of the pixel or the sub-pixel,

a position of the comb teeth of the second comb-shaped electrode disposed nearest to the comb teeth of the first comb-shaped electrode is shifted from a position of the comb teeth of the first comb-shaped electrode in a first direction being parallel to surfaces of the array and counter substrates from the central axis,

a position of the comb teeth of the third comb-shaped electrode disposed nearest to the comb teeth of the first comb-shaped electrode is shifted from a position of the comb teeth of the first comb-shaped electrode in a second direction that is opposite to the first direction from the central axis, and

the comb teeth of the comb-shaped second electrode facing to the comb teeth of the first comb-shaped electrode via the insulating layer comprises a protruding width that protrudes in the first direction from the comb teeth of the first comb-shaped electrode, and the comb teeth of the first comb-shaped electrode and the comb teeth of the second comb-shaped electrode comprise overlapping widths that overlap with each other.

2. The liquid crystal display device according to claim 1, wherein the counter substrate comprises a black matrix having openings that transmit light in a direction perpendicular to the substrate plane, and a color filter formed at the openings.

3. The liquid crystal display device according to claim 1, wherein a plurality of pixels or a plurality of sub-pixels have a shape in which opposite sides are parallel to each other in a plane and the plurality of pixels or the plurality of sub-pixels formed on the array substrate and the counter substrate.

4. The liquid crystal display device according to claim 3, wherein each of the plurality of pixels or the plurality of sub-pixels is divided into four division regions in the plane, and

the comb-shaped first electrode, the comb-shaped second electrode, and the comb-shaped third electrode have longitudinal directions of the comb teeth that are parallel to any side of the division region in every division region in the plane, while the longitudinal directions of the comb teeth are different between the adjoining division regions.

5. The liquid crystal display device according to claim 3, wherein each of the plurality of pixels or the plurality of sub-pixels is divided into four division regions in the plane, and

the comb-shaped first electrode, the comb-shaped second electrode, and the comb-shaped third electrode have longitudinal directions of the comb teeth that are symmetric on two center lines in both a horizontal direction and a vertical direction which pass about a center point of the plurality pixels or the plurality of sub-pixels in the plane, provided in each of the four division regions, and have an angle of inclination with respect to each side of the division region.

6. The liquid crystal display device according to claim 1, wherein the number of the comb teeth of the comb-shaped third electrode in the pixel unit or the sub-pixel unit is larger than the number of the comb teeth of the comb-shaped first electrode.

7. The liquid crystal display device according to claim 1, wherein the comb-shaped first electrode, the comb-shaped second electrode, and the comb-shaped third electrode are each formed by a conductive film transparent to a visible light region.

8. The liquid crystal display device according to claim 1, wherein the number of the comb teeth of the comb-shaped third electrode is an even number of 2 or more in the pixel unit or the sub-pixel unit.

9. The liquid crystal display device according to claim 1, wherein the number of the comb teeth of the comb-shaped first electrode is an even number of 2 or more in the pixel unit or the sub-pixel unit, the number of the comb teeth of the comb-shaped second electrode is an even number of 2 or more in the pixel unit or the sub-pixel unit.

10. The liquid crystal display device according to claim 1 wherein the protruding width is set to 0.5 μ

m to 6 μ

m.