Light pipe and polarized-light source

• US 20060232861A1
• Filed: 04/28/2006
• Published: 10/19/2006
• Est. Priority Date: 05/12/1999
• Status: Abandoned Application

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Miyatake, Minoru, Sakuramoto, Takafumi
• Application Number:
  US11/412,907
• Publication Number:
  US 20060232861A1
• Time in Patent Office: Days
• US Class Current: 359/494
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0257 creating an anisotropic diffusion characteristic, i.e. distributing output differently in two perpendicular axes
• CPC Class Codes: G02B 5/0263 with positional variation of the diffusing properties, e.g. gradient or patterned diffuser
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/3008 comprising dielectric particles, e.g. birefringent crystals embedded in a matrix
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Abstract

A light pipe is obtained by laminating on one or both surfaces of a light-transmitting resin plate a polarized-light scattering plate having fine birefringent domains dispersed therein and hence showing anisotropy in scattering. The polarized-light scattering plate comprises a transparent film having fine domains dispersed therein comprising a liquid crystal polymer which exhibits nematic at temperatures lower than the glass transition temperature of the polymer constituting matrix of the transparent film and has a glass transition temperature of 50° C. or higher. The light pipe as a laminate may further comprise a specular reflection layer, a polarization-retaining lens and a light diffusion layer laminated thereon. The light pipe may further comprise a light source mounted at least on one side face thereof to provide a planar polarized-light source.

Claims

1. A light pipe comprising:

a light-transmitting resin plate;

a polarized-light scattering plate laminated on at least one surface of said light-transmitting resin plate, said polarized-light scattering plate having fine birefringent domains dispersed therein to exhibit anisotropy in scattering depending on a polarization direction; and

a light path interposed between said light-transmitting resin plate and said polarized-light scattering plate to thereby partially bond said said light-transmitting resin plate and said polarized-light scattering plate in close contact.

2. A light pipe according to claim 1, wherein said light path comprises a convex portion in a roughened structure provided on one of the light-transmitting resin plate and the polarized-light scattering plate, and said roughened structure has a rectangular section comprising a flat surface on concave and convex portions thereof.

3. A light pipe according to claim 1, wherein there is a variation of distribution density of light path.

4. A light pipe according to claim 1, wherein length of said light path is from 0.5 to 1,000 gm.

5. A light pipe according to claim 1, wherein the light-transmitting resin plate side of the light path has a section having a continuous primary differential curve free of acute corner.

6. A light pipe according to claim 1, wherein said light path is made of an adhesive material.

7. A light pipe according to claim 1, further comprising a polarization-retaining reflection layer on one of both surfaces of said light pipe.

8. A light pipe according to claim 1, further comprising a polarization-retaining light diffusion layer on one of both surfaces of said light pipe.

9. A light pipe according to claim 1, further comprising a polarization-retaining lens sheet on one of both surfaces of said light pipe.

10. A polarized-light source comprising:

light pipe according to any one of claim 1;

and a light source provided at least on one side face of said light pipe.