Optical efficiency enhancing film and liquid crystal display using the same

• US 7,623,208 B2
• Filed: 06/29/2004
• Issued: 11/24/2009
• 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
• Primary Examiner(s): Dudek; James A
• Application Number:
  US10/878,408
• Publication Number:
  US 20050140883A1
• Time in Patent Office: 1,974 Days
• Field of Search: 349/119, 349/96, 349/120, 349/117, 359315-317
• US Class Current: 349/119
• 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:

a plurality of uniaxial films made of a refractive index anisotropic material; and

a plurality of intermediate films, wherein each intermediate film is a C-plate of biaxial film or a negative C-plate aligned vertically, and each of the uniaxial films and each of the intermediate films are alternatively laminated to contact each other,

wherein each of the uniaxial films is an A-plate.

2. 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;

an optical efficiency enhancing film coated on an inner surface of the lower substrate, wherein optical efficiency enhancing film includes a plurality of uniaxial films made of a refractive index anisotropic material and a plurality of intermediate films, each intermediate film being a C-plate of biaxial film or a negative C-plate aligned vertically, and each of the uniaxial films and each of the intermediate films being alternatively laminated to contact each other;

a first polarization plate disposed on the optical efficiency enhancing film;

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

a backlight assembly disposed on outer surface of the lower substrate,

wherein the optical efficiency enhancing film has an optical transmission axis substantially identical to the first polarization plate, and has an optical transmission axis perpendicular to the second polarization plate.

3. The liquid crystal display device according to claim 2, wherein the optical efficiency enhancing film has a property of a polarizer for converting natural light into linearly polarized light.