Patent ID: 7576313

Claim:
A light source device, comprising: first and second light emitting parts that emit first light and second light, respectively; a polarization separating part that separates each of the first and second lights into first polarized light in a first vibrating direction and second polarized light in a second vibrating direction, respectively, by transmitting the first polarized light and reflecting the second polarized light, the second vibrating direction being substantially orthogonal to the first vibrating direction; a mirror reflecting the second polarized light of the first light and the first polarized light of the second light toward each of the first and second light emitting parts that emitted the reflected the first and second polarized lights; a phase plate provided between at least one of the first and second light emitting parts and the polarization separating part, the phase plate shifting a phase of incident light by ¼, the first or second polarized lights that is reflected by the mirror and is transmitted in or reflected by the polarization separating part being incident on the phase plate, and an optical element that is arranged between at least one of the first and second light emitting parts and the polarization separating part that directs the first or second lights from the first or second light emitting parts to the polarization separating part, the first and second light emitting parts including a reflection part that reflects the first or second polarized lights through the phase plate so as to be re-incident on the phase plate, in the direction of the polarization separating part, the first and second light emitting parts being a solid light emitting element, the polarization separating part synthesizing the first polarized light that passes through the polarization separating part, and the second polarized light that is reflected on the polarization separating part to cause the synthesized light to travel in a predetermined direction, and the optical element being a collective lens which collects the first or second lights from the first or second light emitting parts.