Brightness enhancement film for liquid crystal display and manufacturing method thereof

• US 7,776,411 B2
• Filed: 06/25/2009
• Issued: 08/17/2010
• 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: Hwang, Jin-Taek, Park, Jong-Dae, Choi, Jin-Sung
• Primary Examiner(s): Visconti; Geraldina
• Application Number:
  US12/491,722
• Publication Number:
  US 20090262282A1
• Time in Patent Office: 418 Days
• Field of Search: 252/299.01, 252/299.6, 428/1.1, 430/20, 430/270.1, 349/117
• 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:

melting a high molecular weight resin and organic particles having a core shell structure;

cooling the melted high molecular weight resin and the organic particles with a cooling roll to form a high molecular weight film; and

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

2. The method of claim 1, wherein the organic particles are made of methacrylate butadiene styrene.

3. The method of claim 1, wherein the high molecular weight resin comprises one of a polycarbonate, a poly ethylene terephthalate, a polyimide, 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.

4. The method of claim 2, wherein the high molecular weight resin and the organic particles have a powder type structure before the melting, and

wherein the melting of the high molecular weight resin and the organic particles is performed at a temperature between the 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 180°

Celsius.

5. The method of claim 4, wherein the glass transition temperature of the high molecular weight film ranges from between approximately 300°

Celsius to 330°

Celsius.

6. The method of claim 1, wherein the temperature of the cooling roll ranges from between approximately 100°

Celsius to 140°

Celsius.

7. The method of claim 1, wherein a concentration of the high molecular weight resin is between approximately 70 wt % and 99 wt % and a concentration of the organic particles is between approximately 1 wt % and 30 wt %.

8. The method of claim 1, wherein the drawing of the high molecular weight film is performed at a temperature between the 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.

9. The method of claim 1, wherein the high molecular weight film is extended by approximately 1.1 to 8 times through the drawing with heating.

10. A brightness enhancement film for a liquid crystal display comprises a high molecular weight film and organic particles having a core shell structure and distributed in the high molecular weight film.

11. The brightness enhancement film of claim 10, wherein the high molecular weight film is drawn in a predetermined direction.

12. The brightness enhancement film of claim 10, wherein the high molecular weight film comprises one of a polycarbonate, a poly ethylene terephthalate, a polyimide, 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. The brightness enhancement film of claim 10, wherein the organic particles are made of methacrylate butadiene styrene.

14. 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 and the back light unit, the optical film unit comprising a diffusion film, a prism film, and a brightness enhancement film,

wherein the brightness enhancement film comprises a high molecular weight film and organic particles having a core shell structure and distributed in the high molecular weight film.

15. The liquid crystal display of claim 14, wherein the brightness enhancement film is provided on the diffusion film and the prism film is provided on the brightness enhancement film.

16. The liquid crystal display of claim 14, 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.

17. 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;

providing 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;

providing a prism film on the second UV cross-linker; and

illuminating a UV ray at the first and second UV cross-linkers,

wherein the brightness enhancement film comprises a high molecular weight film and organic particles.

18. The method of claim 17, wherein the organic particles have a core shell structure and are distributed in the high molecular weight film.

19. The method of claim 18, 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 technique or a blading technique.

20. 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 and the back light unit, the optical film unit comprising a diffusion film, a prism film, and a brightness enhancement film,

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,

wherein the brightness enhancement film comprises a high molecular weight film and organic particles.

21. The liquid crystal display of claim 20, wherein the organic particles have a core shell structure and are distributed in the high molecular weight film.

22. The liquid crystal display of claim 21, wherein the brightness enhancement film is provided on the diffusion film and the prism film is provided on the brightness enhancement film.