Patent ID: 7220038

Claim:
A light source device comprising primary light sources, a light guide having two light incident surfaces opposed to each other and adapted to receive light emitted from said primary light sources, and a light outgoing surface for guiding and emitting the received light, and a light deflection element disposed adjacent to said light guide on a light outgoing surface side thereof, wherein said light deflection element has a light receiving surface for receiving the light and a light emitting surface located on a side opposite to said light receiving surface for emitting the received light, said light receiving surface has a plurality of elongated prisms arrayed substantially parallel to each other and each composed of two prism faces, and each of said prism faces is formed by at least two faces having different inclination angles wherein one of said faces located closer to said light emitting surface has a larger inclination angle and a difference between an inclination angle of one of said faces closest to said light emitting surface and an inclination angle of the other one of said faces farthest from said light emitting surface is 15 degrees or less.