Patent ID: 8640368

Claim:
A light source device comprising: a highly directional point light source; a light source installation part with a prescribed area on which the point light source is installed; and a side reflection part that is vertically arranged to a prescribed height from the periphery of the light source installation part, an inner wall surface surrounded by the light source installation part and the side reflection part being formed of a reflection surface; wherein the side reflection part is formed of a light-transmitting reflector plate at least partially provided with a reflection/transmission pattern with a plurality of reflection/transmission parts reflecting and transmitting a part of light from the point light source, with a plurality of virtual radiation lines being drawn at prescribed angles from the point light source on a surface of the light-transmitting reflector plate, the reflection/transmission pattern is set so that relationship of Re1>Re2 and Tr1<Tr2 is satisfied where Re1 denotes a reflection rate of and Tr1 denotes a transmission rate of the reflection/transmission parts that have equal distance from the point light source and are on the radiation lines whose directivity angle is small, and Re2 denotes a reflection rate of and Tr2 denotes a transmission rate of the reflection/transmission parts that are on the radiation lines whose directivity angle is large, wherein the reflection/transmission parts of the reflection/transmission pattern are structured by forming the light-transmitting reflector plate with a reflective material and providing the reflective material with a through hole having an opening of a prescribed size, and wherein the light-transmitting reflector plate is provided with a non-through hole or made thin at an area near the point light source, instead of the through hole.