Patent ID: 8669571
Filing Date: 2014-03-11
Classification: G02B,G09F,H01L

Abstract:
1. A light distribution controller, comprising: a first optical member configured to cover a light source; and a second optical member configured to cover the first optical member, wherein the first optical member has a shape of a circular truncated cone or of a prismoid which tapers from the light source, and has a first concave portion which is formed from an upper surface of the circular truncated cone or prismoid in a downward direction along a central axis of the circular truncated cone or prismoid, the first concave portion has an opening whose area increases in an upward direction along the central axis, light emitted from the light source has a Lambertian light distribution characteristic, and has a maximum light intensity in a direction along the central axis, when outputting the light emitted from the light source toward the second optical member, the first optical member converts the light into light having a light distribution characteristic which has an annular peak of light intensity centered around the central axis, the second optical member has a second concave portion formed along the central axis, the second concave portion having an opening whose area increases in an upward direction along the central axis, and of the light having the light distribution characteristic incident from the first optical member upon the second optical member, light incident upon a surface forming the second concave portion is totally reflected at the surface.