ANNULAR LIGHT GUIDE

• US 20060291183A1
• Filed: 06/15/2006
• Published: 12/28/2006
• Est. Priority Date: 06/23/2005
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Kobayashi, Ayumu, Nishiyama, Yoshinori
• Granted Patent: US 7,500,774 B2
• Time in Patent Office: Days
• US Class Current: 362/26
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G05G 1/105 comprising arrangements for illumination

Abstract

An annular light guide is provided. The annular light guide is made of optically transparent material, and is provided with an annular body that is an integrated combination of a light inlet and a light outlet. A light source is disposed in a cavity formed in the light inlet. Illumination light is emitted from the front surface 16c of the light outlet.

Claims

1. An annular light guide that is a molded product made of optically transparent material, comprising:

a light inlet that includes a cavity in which a light source is to be disposed; and

a toric light outlet

wherein the annular light guide is constructed such that the front surface of the light outlet faces the back of illumination area, and light traveling from the light source to the other side of the light inlet is reflected at said other side of the light inlet.

2. The annular light guide according to claim 1, wherein the cavity is a through-hole passing through the light inlet in the through-thickness direction.

3. The annular light guide according to claim 1, wherein collective lenses that have a convex lens shape and refract light from the light source to guide the light to the light outlet are formed in part of the inner wall surface of the light inlet in which the inner wall demarcates the cavity.

4. The annular light guide according to claim 1, wherein outward projected fringes are formed on an external wall surface of said other side of the light inlet so as to extend in the through-thickness direction.

5. The annular light guide according to claim 4, wherein the outward projected fringes have one part of the surface closer to a symmetry line passing through the center of the light inlet and the light outlet is broader than the other part of surface farther from the symmetry line.

6. The annular light guide according to claim 1, wherein inward projected fringes are in a region facing said other side on the inner wall surface of the light inlet that extends in the through-thickness direction

7. The annular light guide according to claim 1;

where in the toric light outlet is continuous to one side of the light inlet.

8. The annular light guide according to claim 6 wherein light from the light source is refracted by the inward projected fringes to travel in predetermined directions to said other side.