Granted Patent B2

US 7,978,301 · App. 11/774,763 · Granted Jul 12, 2011

Abstract

Claims (30)

1. A liquid crystal display device comprising

a first substrate and a second substrate;

polarizing plates provided on the first substrate and the second substrate, respectively;

a liquid crystal layer located between the first substrate and the second substrate; and

pixel electrodes and common electrodes provided on the first substrate,

wherein:

the liquid crystal layer has such a property that optical anisotropy is induced therein by a change of an optically isotropic state caused by application of a voltage;

the pixel electrodes or the common electrodes are formed in an interdigital form;

a surface layer is formed directly on interdigitally formed pixel electrodes, each interdigitally formed pixel electrode having side walls tapered from a top to a bottom with a taper angle θ in the range of 0°<θ<45°;

an electric field is applied to the liquid crystal layer by a potential difference applied between the pixel electrodes and the common electrodes, and

the surface layer is located in contact with a surface of the liquid crystal layer and the surface layer has a periodic structure of 400 nm or less in size, and

the surface layer is formed on the first substrate only and is not formed on the second substrate.

2. A liquid crystal display device according to claim 1 , wherein the first substrate includes a plurality of pixels located thereon in the form of a matrix, and each of the plurality of pixels comprises a pixel electrode, a common electrode and a thin-film transistor.

3. A liquid crystal display device according to claim 2 , wherein:

the pixel electrodes are formed in the form of an interdigital pattern;

the common electrodes are formed in the form of a flat plate; and

the pixel electrodes are arranged in at least two interdigital patterns, which are different in direction by not more than 92° and not less than 88°, in each of the plurality of said pixels.

4. A liquid crystal display device according to claim 1 , wherein the first substrate includes a passivation layer located between the interdigitally formed pixel electrodes and common electrodes located on the first substrate.

5. A liquid crystal display device according to claim 1 , wherein said liquid crystal layer is obtained by thermal polymerization.

6. A liquid crystal display device according to claim 1 , wherein the surface layer is formed by rubbing.

7. A liquid crystal display device according to claim 1 , wherein a periodic structure in the surface layer is formed by light irradiation.

8. A liquid crystal display device according to claim 1 , wherein:

the liquid crystal display device further comprises an image signal line, and

a periodic structure is formed at only a side at which the pixel electrodes exist from the image signal line.

9. A liquid crystal display device according to claim 8 , wherein the periodic structure is formed in only a region adjacent the pixel electrodes.

10. A liquid crystal display device according to claim 1 , wherein:

the surface layer includes a portion having a first film thickness and a portion having a second film thickness which is thinner than the first film thickness,

the pixel electrodes are formed in only the portion having a first film thickness, and

the periodic structure is formed in only the portion having a first film thickness.

11. A liquid crystal display device according to claim 1 , wherein the periodic structure is in the form of pillar.

Assignments (8)