Optical efficiency enhancing film and liquid crystal display using the same

• US 20050140883A1
• Filed: 06/29/2004
• Published: 06/30/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Man Hoan, Lee, Ha Young
• Granted Patent: US 7,623,208 B2
• Time in Patent Office: Days
• US Class Current: 349/120
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133528 Polarisers

Abstract

The present invention relates to an optical efficiency enhancing film and an LCD using the same. The LCD of the present invention is provided with an optical efficiency enhancing film that includes uniaxial films made of a refractive index anisotropic material and isotropic films, wherein the uniaxial films and the isotropic films are alternatively laminated. Then, optical efficiency as well as polarization may be enhanced to thereby improve the brightness of the LCD.

Claims

1. An optical efficiency enhancing film for a liquid crystal display device, comprising:

uniaxial films made of a refractive index anisotropic material; and

isotropic films, wherein the uniaxial films and the isotropic films are alternatively laminated.

2. The film according to claim 1, wherein the uniaxial film is an A-plate.

3. An optical efficiency enhancing film for a liquid crystal display device, comprising:

a first film of a refractive index anisotropic material; and

a second film on the first film, wherein the first film and the second film are alternately arranged.

4. The optical efficiency enhancing film of claim 3, wherein the first film is a uniaxial film.

5. The optical efficiency enhancing film of claim 4, wherein the uniaxial film is an A-plate.

6. The optical efficiency enhancing film of claim 3, wherein the second film is selected from the group consisting of a C-plate of biaxial film and a negative C-plate aligned vertically.

7. A liquid crystal display device, comprising:

a lower substrate provided with pixel regions defined by gate lines and data lines, and thin film transistors arranged in matrix configuration;

an upper substrate corresponding to the lower substrate and provided with a color filter layer consisting of a plurality of color filter patterns to represent colors;

a liquid crystal layer interposed between the upper substrate and lower substrate;

a first polarization plate disposed on the lower substrate, capable of passing linearly polarizing natural light;

a second polarization plate disposed on the upper substrate and having an optical transmission axis perpendicular to that of the first polarization plate; and

an optical efficiency enhancing film formed on the lower substrate and having an optical transmission axis substantially identical to that of the first polarization plate.

8. The liquid crystal display device according to claim 7, wherein the optical efficiency enhancing film is made of a refractive index anisotropic material.

9. The liquid crystal display device according to claim 7, wherein the optical efficiency enhancing film has a property of a polarizer for converting natural light into linearly polarized light.

10. The liquid crystal display device according to claim 7, wherein the optical efficiency enhancing film is coated and formed on the lower substrate.

11. The liquid crystal display device according to claim 7, wherein the first polarization plate is coated and formed on the optical efficiency enhancing film.

12. The liquid crystal display device according to claim 7, wherein the optical efficiency enhancing film is formed between the liquid crystal layer and the lower substrate.

13. The liquid crystal display device according to claim 7, wherein the optical efficiency enhancing film is formed on an outer surface of the lower substrate.

14. An optical efficiency enhancing film, comprising:

a first uniaxial film including a refractive index anisotropic material;

an intermediate film on the first uniaxial film; and

a second uniaxial film including a refractive index anisotropic material.

15. The optical efficiency enhancing film according to claim 14, wherein the first uniaxial film is an A-plate.

16. The optical efficiency enhancing film according to claim 14, wherein the intermediate film is an isotropic film.

17. The optical efficiency enhancing film according to claim 14, wherein the intermediate film is selected from the group consisting of a C-plate of biaxial film and a negative C-plate aligned vertically.