Patent ID: 8272772
Filing Date: 2012-09-25
Classification: G02B,G02F

Abstract:
1. A surface illuminating light source device comprising: a group of light sources including a single point-light source or a combination of a plurality of point-light sources that emit light; an optically transmissive light guide body propagating light from the light source and having a radiation surface at a prescribed position in the radiation direction; a casing closing surfaces of the light guide body except the radiation surface and having an inner reflection unit formed of a bottom surface and a side reflection section that reflect light, in which the light source is arranged substantially at a center of the bottom surface; and a radiation side reflection unit arranged on the radiation surface, wherein the radiation side reflection unit is formed of a member that reflects or passes light propagating inside the light guide body at a prescribed rate, and an opening section is formed on a periphery of the radiation side reflection unit while a central portion of the radiation side reflection unit is a non-opening section so that an amount of light passing through the radiation side reflection unit increases as it gets farther from a center of the radiation surface facing the light source, wherein when proportion of total area of the opening section against a prescribed standard area is opening rate A, b and c are invariables, and distance from a center of the radiation surface facing the light source is x, the opening section satisfies the following formula: