Patent ID: 7726828

Claim:
A planer illumination light source device comprising: a highly directional point-light source; a casing having a bottom plane and a side plane of prescribed sizes, and formed with an opening, the casing having, at an inner wall surface thereof, an inside reflection part and a side reflection part that reflect or irregularly reflect light; and radiation side reflection means that covers the opening and transmits, reflects or irregularly reflects light, wherein the casing is provided with the point-light source arranged at the center of the bottom plane thereof, the radiation side reflection means has a central reflection part in a prescribed area at a spot immediately above the point-light source and an outward reflection part arranged at an outer periphery of the central reflection part, the outward reflection part is formed of a reflection member having a prescribed reflectance that transmits, reflects, or irregularly reflects a part of light, and the central reflection part is formed of a light transmissive reflection member having a higher reflectance than that of the outward reflection part.