Liquid crystal display

• US 6,005,650 A
• Filed: 06/30/1998
• Issued: 12/21/1999
• Est. Priority Date: 06/30/1997
• Status: Expired due to Term

• Current Assignee: BOE HYDIS Technology Company Limited (SK Hynix Inc.)
• Original Assignee: Hyundai Electronics Industries Co. Ltd. (SK Hynix Inc.)
• Inventors: Lee, Seung Hee, Kim, Hyang Yul, Park, Jang Sick
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US09/107,797
• Time in Patent Office: 539 Days
• Field of Search: 349/130, 349/117, 349/118, 349/120, 349/143, 349/141, 349/123
• US Class Current: 349/130
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133753 with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Abstract

A liquid crystal display. The display has a first substrate and a second substrate. One of the substrates is disposed opposite the other a first distance apart. Each of the substrates has an inner surface and an outer surface that is opposite the inner surface. A liquid crystal layer is sandwiched between the inner surfaces of the substrates. At least a pair of a first electrode and a second electrode are arranged along a first direction on the inner surface of the first substrate. The first electrode is disposed parallel to the second electrode a second distance apart. A first homeotropic alignment film is disposed on the first substrate including the first and second electrodes. At least a pair of a third electrode and a fourth electrode are arranged along a second direction on the second substrate. The third electrode is disposed parallel to the fourth electrode a third distance apart, wherein the first direction is perpendicular to the second direction. A second homeotropic alignment film is (disposed on the second substrate including the third and fourth electrodes. A first polarizer is disposed on the outer surface of the first substrate; and a second polarizer is disposed on the outer surface of the second substrate.

Claims

1. A liquid crystal display comprising:

a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrate having an inner surface and an outer surface, wherein said inner surfaces are opposite each other;

a liquid crystal layer sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart. said first and said second electrodes adapted to generate a first electric field therebetween;

a first homeotropic alignment film disposed on the first substrate including the first and the second electrodes;

a third electrode and a fourth electrode arranged along a second direction on the inner surface of said second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, said third and said fourth electrode adapted to generate a second electric field therebetween, wherein the first direction is perpendicular to the second direction;

a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

a first polarizer disposed on the outer surface of the first substrate; and

a second polarizer disposed on the outer surface of the second substrate.

2. The liquid crystal display in claim 1, wherein said liquid crystal molecules have a positive dielectric anisotropy.

3. The liquid crystal display in claim 1, wherein the first polarizer has a first polarizing axis and the second polarizer has a second polarizing axis, said first polarizing axis is perpendicular to the second polarizing axis.

4. The liquid crystal display in claim 3, wherein said first polarizing axis deviates by approximate 45 degrees from a first electric field direction produced between said first and second electrodes in the counterclockwise direction.

5. The liquid crystal display in claim 3, wherein said second polarizing axis deviates by approximate 45 degrees from a second electric field direction produced between said third and fourth electrodes in the counterclockwise direction.

6. The liquid crystal display as in claim 1, wherein said first distance is at least about 105 percent as long as said second distance.

7. The liquid crystal display as in claim 1, wherein said first distance is at least about 105 percent as long as said third distance.

8. A liquid crystal display comprising:

a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrate having an inner surface and an outer surface, wherein said inner surfaces are opposite each other;

a liquid crystal layer sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

at least a pair of a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart, said first and said second electrodes adapted to generate a first electric field therebetween;

a first homeotropic alignment film disposed on the first substrate including the first and second electrodes;

at least a pair of a third electrode and a fourth electrode arranged along a second direction on the second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, said third and said fourth electrode adapted to generate a second electric field therebetween, wherein the first direction is perpendicular to the second direction;

a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

a first polarizer disposed on the outer surface of the first substrate;

a second polarizer disposed on the outer surface of the second substrate; and

an optical compensating film disposed between said first polarizer and the outer surface of said first substrate.

9. The liquid crystal display in claim 8, wherein the optical compensating film is made of a liquid crystal film including a plurality of molecules of negative birefringent index.

10. The liquid crystal display in claim 8, wherein said liquid crystal molecules have a property of positive dielectric anisotropy.

11. The liquid crystal display in claim 8, wherein said optical compensating film has a bi-directionally stretched structure.

12. A liquid crystal display comprising:

a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrate having an inner surface and an outer surface that is opposite the inner surface;

a liquid crystal layer sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

at least a pair of a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart;

a first homeotropic alignment film disposed on the first substrate including the first and second electrodes;

at least a pair of a third electrode and a fourth electrode arranged along a second direction on the second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, wherein the first direction is perpendicular to the second direction;

a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

a first polarizer disposed on the outer surface of the first substrate;

a second polarizer disposed on the outer surface of the second substrate; and

an optical compensating film disposed between said first polarizer and the outer surface of said first substrate;

wherein said optical compensating film comprises a plurality of cured liquid crystal molecules with disk structure, each molecule having radius greater than height thereof.

13. The liquid crystal display in claim 12, wherein said optical compensating film has a retardation, said retardation is equal to a product of anisotropic refractive index of said liquid crystal molecules and said first distance.

14. A liquid crystal display comprising:

a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrates having an inner surface and an outer surface, wherein said inner surfaces are opposite each other;

P1 a liquid crystal layer sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

at least a pair of a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart, said first and said second electrodes adapted to generate a first electric field therebetween;

a first homeotropic alignment film disposed on the first substrate including the first and second electrodes;

at least a pair of a third electrode and a fourth electrode arranged along a second direction on the second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, said third and said fourth electrode adapted to generate a second electric field therebetween, wherein the first direction is perpendicular to the second direction;

a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

a first polarizer disposed on the outer surface of the first substrate;

a second polarizer disposed on the outer surface of the second substrate; and

an optical compensating film disposed between said first polarizer and the outer surface of said first substrate,

wherein said first distance is greater than the second distance and the third distance.

15. The liquid crystal display in claim 14, wherein the optical compensating film is made of a liquid crystal film including a plurality of molecules of negative birefringent index.

16. The liquid crystal display in claim 14, wherein liquid crystal molecules have a property of positive dielectric anisotropy.

17. The liquid crystal display in claim 14, wherein said optical compensating film has a bi-directionally stretched structure.

18. A liquid crystal display comprising:

a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrates having an inner surface and an outer surface that is opposite the inner surface;

a liquid crystal laver sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

at least a pair of a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart;

a first homeotropic alignment film disposed on the first substrate including the first and second electrodes;

at least a pair of a third electrode and a fourth electrode arranged along a second direction on the second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, wherein the first direction is perpendicular to the second direction;

a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

a first polarizer disposed on the outer surface of the first substrate;

a second polarizer disposed on the outer surface of the second substrate; and

an optical compensating film disposed between said first polarizer and the outer surface of said first substrate,

wherein said first distance is greater than the second distance and the third distance;

wherein said optical compensating film comprises a plurality of cured liquid crystal molecules with disk structure, each molecule having radius greater than height thereof.

19. The liquid crystal display in claim 18, wherein said optical compensating film has a retardation, said retardation is equal to a product of anisotropic refractive index of said liquid crystal molecules and said first distance.

20. A method for forming a liquid crystal display, said method comprising:

providing a first substrate and a second substrate, said first substrate being disposed opposite said second substrate and being disposed a first distance apart, each of said substrate having an inner surface and an outer surface, wherein said inner surfaces are opposite each other;

forming a liquid crystal layer sandwiched between the inner surfaces of the substrates, said liquid crystal layer comprising a plurality of liquid crystal molecules;

forming a first electrode and a second electrode arranged along a first direction on said inner surface of said first substrate, the first electrode being disposed parallel to the second electrode a second distance apart, said first and said second electrodes adapted to generate a first electric field therebetween;

forming a first homeotropic alignment film on the first substrate including the first and second electrodes;

forming a third electrode and a fourth electrode arranged along a second direction on the second substrate, the third electrode being disposed parallel to the fourth electrode a third distance apart, said third and said fourth electrode adapted to generate a second electric field therebetween, wherein the first direction is perpendicular to the second direction;

forming a second homeotropic alignment film disposed on the second substrate including the third and fourth electrodes;

forming a first polarizer disposed on the outer surface of the first substrate; and

forming a second polarizer disposed on the outer surface of the second substrate.

21. The method of claim 20, wherein said liquid crystal molecules have a positive dielectric anisotropy.

22. The method of claim 20, wherein the first polarizer has a first polarizing axis and the second polarizer has a second polarizing axis, said first polarizing axis is perpendicular to the second polarizing axis.

23. The method of claim 22, wherein said first polarizing axis deviates by approximate 45 degrees from a first electric field direction produced between said first and second electrodes in the counterclockwise direction.

24. The method of claim 22, wherein said second polarizing axis deviates by approximate 45 degrees from a second electric field direction produced between said third and fourth electrodes in the counterclockwise direction.