Planar light source unit

• US 20060181903A1
• Filed: 01/24/2006
• Published: 08/17/2006
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Okuwaki, Daisaku
• Granted Patent: US 7,517,130 B2
• Time in Patent Office: Days
• US Class Current: 362/619
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

A planar light source unit including a light guiding plate (1) having an anisotropic diffusing surface (1h) which emits anisotropic diffusion light, and a light emitting source (2) for supplying light to the light guiding plate, the anisotropic diffusing surface being formed into a shape configured to give a gradation of the anisotropic diffusion light intensity.

Claims

1. A planar light source unit, comprising:

a light guiding plate including an anisotropic diffusing surface which emits anisotropic diffusion light; and

a light emitting source comprising at least one light emitting diode for supplying light to the light guiding plate,

wherein the anisotropic diffusing surface is formed into a shape configured to give a gradation of the anisotropic diffusion light intensity.

2. The planar light source unit according to claim 1,

wherein the gradation of the anisotropic diffusion light intensity is set to vary stepwise.

3. The planar light source unit according to claim 1,

wherein the gradation of the anisotropic diffusion light intensity is set to vary non-stepwise.

4. The planar light source unit according to claim 1,

wherein the anisotropic diffusing surface comprises a hologram diffusing surface.

5. The planar light source unit according to claim 1,

wherein the anisotropic diffusing surface comprises a hairline diffusing surface.

6. The planar light source unit according to claim 1,

wherein the anisotropic diffusing surface has a plurality of diffusing surface areas.

7. The planar light source unit according to claim 6,

wherein the plurality of diffusing surface areas are arranged from a position close to the light emitting source to a position remote from the light emitting source.

8. The planar light source unit according to claim 6,

wherein the plurality of diffusing surface areas are set so that diffusion light emitted from the diffusing surface areas is different in exit angular width, anisotropic diffusion light intensity, brightness or conversion efficiency.