Brightness enhancement film for liquid crystal display and manufacturing method thereof

• US 7,572,490 B2
• Filed: 04/26/2005
• Issued: 08/11/2009
• Est. Priority Date: 04/27/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Jong-Dae, Choi, Jin-Sung, Hwang, Jin-Taek
• Primary Examiner(s): Visconti; Geraldina
• Application Number:
  US11/114,214
• Publication Number:
  US 20050275334A1
• Time in Patent Office: 1,568 Days
• Field of Search: 430/20, 428/1.1, 252/299.01, 349/1, 349/2
• US Class Current: 428/1.1
• CPC Class Codes: B29D 11/00278 Lenticular sheets B29D11/00269 takes precedence
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance

Abstract

A liquid crystal display having a brightness enhancement film and a method of manufacturing the brightness enhancement film, the method including providing a solution of high molecular weight resin on a high molecular weight film, uniformly distributing the solution of high molecular weight resin on the high molecular weight film, and drying the solution of high molecular weight resin to form a high molecular weight resin layer, wherein the high molecular weight resin layer has a hexagonal lattice structure.

Claims

1. A method of manufacturing a brightness enhancement film for a liquid crystal display comprising:

providing a solution of high molecular weight resin on a high molecular weight film;

uniformly distributing the solution of high molecular weight resin on the high molecular weight film;

drying the solution of high molecular weight resin to form a high molecular weight resin layer, wherein the high molecular weight resin layer has a hexagonal lattice structure; and

drawing the high molecular weight film and the high molecular weight resin layer in a predetermined direction with heating.

2. The method of claim 1, wherein the high molecular weight film comprises a polycarbonate or a poly ethylene terephthalate material.

3. The method of claim 1, wherein the hexagonal lattice structure of the high molecular weight resin layer is approximately 10 nm to 800 nm thick.

4. The method of claim 1, wherein the solution of the high molecular weight resin is uniformly applied by a spin coating process or blading process.

5. The method of claim 1, wherein the high molecular weight resin layer comprises one of a polysulfone, a polymethylmethacrylate, a polystyrene, a polyvinylchloride, a polyvinylalcohol, a polynorbonene, a polymer formed by copolymerization of the above identified polymers, or a derivative thereof.

6. The method of claim 1, wherein the drawing of the high molecular weight film is performed at a temperature between a glass transition temperature of the high molecular weight film and a temperature that is greater than the glass transition temperature of the high molecular weight film by approximately 100°

Celsius.

7. The method of claim 1, wherein the high molecular weight film and the high molecular weight resin layer are each elongated between approximately 1.1 to 8 times through the drawing with heating.

8. A brightness enhancement film for a liquid crystal display comprising:

a high molecular weight film; and

a high molecular weight resin layer formed on the high molecular weight film, wherein the high molecular weight resin layer has a hexagonal lattice structure and wherein the hexagonal lattice structure is positioned along an elongated direction of the brightness enhancement film.

9. The brightness enhancement film display of claim 8, wherein both the high molecular weight film and the high molecular weight resin layer are drawn in a predetermined direction with heating.

10. The brightness enhancement film display of claim 8, wherein the high molecular weight film comprises a polycarbonate or a poly ethylene terephthalate material.

11. The brightness enhancement film for a liquid crystal display of claim 8, wherein the hexagonal lattice structure of the high molecular weight resin layer is approximately 10 nm to 800 nm thick.

12. The brightness enhancement film of claim 8, wherein the high molecular weight resin layer comprises one of a polysulfone, a polymethylmethacrylate, a polystyrene, a polyvinylchloride, a polyvinylalcohol, a polynorbonene, a polymer formed by copolymerization of the above identified polymers, or a derivative thereof.

13. A method of manufacturing a liquid crystal display comprising:

providing a first UV cross-linker on a diffusion film;

uniformly distributing the first UV cross-linker on the diffusion film disposing a brightness enhancement film on the first UV cross-linker;

providing a second UV cross-linker on the brightness enhancement film;

uniformly distributing the second UV cross-linker on the brightness enhancement film;

disposing a prism film on the second UV cross-linker;

illuminating a UV ray at the first and second UV cross-linkers, wherein the brightness enhancement film has a high molecular weight film and a high molecular weight resin layer formed on the high molecular weight film, the high molecular weight film having a hexagonal lattice structure; and

drawing the high molecular weiciht film and the high molecular weight resin layer in a predetermined direction with heating.

14. The method of claim 13, further comprising:

uniformly applying the first and second UV cross-linkers on the diffusion film and the brightness enhancement film, respectively, by a spin coating or blading technique.

15. A liquid crystal display comprising:

a display unit displaying images;

a back light unit providing light to the display unit; and

an optical film unit provided between the display unit, the optical film unit comprising a diffusion film, a prism film, and a brightness enhancement film, wherein the brightness enhancement film has a high molecular weight film and a high molecular weight resin layer formed on the high molecular weight film, the high molecular weight resin layer having a hexagonal lattice structure, and wherein the hexaqonal lattice structure is positioned along an elongated direction of the brightness enhancement film.

16. The liquid crystal display of claim 15, wherein the brightness enhancement film is provided on the diffusion film and the prism film is provided on the brightness enhancement film.

17. The liquid crystal display of claim 16, further comprising:

a first UV cross-linker connecting together the diffusion film and the brightness enhancement film; and

a second UV cross-linker connecting together the brightness enhancement film and the prism film.