Light source device

A light source device comprising, at least, a primary light source, a light guide that guides light emitted from said primary light source and has a light incident surface on which the light emitted from said primary light source is incident, and a light outgoing surface from which the guided light exits, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface,

• wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and a full width half maximum of a luminance distribution of outgoing light from the light exit surface of said light deflector is 19 to 26 degrees, and said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 1 to 8 degrees when parallel light is incident thereon.

A light source device comprising, at least, two primary light sources, a light guide that guides lights emitted from said primary light sources and has two light incident surfaces on which the lights emitted from said two primary light sources are respectively incident and which are disposed on opposite sides to each other, and a light outgoing surface from which the guided lights exit, said light guide having a developed length greater than 8 cm and equal to or less than 28 cm, a light deflector having a light entrance surface disposed adjacent to the light outgoing surface of said light guide and located so as to face said light outgoing surface, and a light exit surface on an opposite side relative to said light entrance surface, and a light diffuser having an incident surface disposed adjacent to the light exit surface of said light deflector and located so as to face the light exit surface of said light deflector, and an outgoing surface on an opposite side relative to said incident surface,

• wherein a plurality of elongated prisms arrayed side by side are formed at the light entrance surface of said light deflector, each of said elongated prisms has two prism surfaces and, at least one of said prism surfaces is formed into a convex curved surface shape, and the two prism surfaces intersect at a point facing the light guide, and said light diffuser is configured in such a manner that a full width half maximum of an outgoing light luminous intensity distribution is 0.7 to 13 degrees when parallel light is incident thereon.