Patent ID: 8016427

Claim:
A light source device comprising: at least two coherent light sources; and a diffraction part for diffracting lights emitted from the coherent light sources, such that the lights propagate through the same optical path, wherein the lights have different incident angles upon contacting the diffraction part, and the diffraction part is for receiving the lights having different incident angles and outputting a coaxial beam comprising said lights, wherein said diffraction part comprises: a first diffraction element for receiving at least two lights, and diffracting at least one of the received lights so that the received at least two lights propagate through the same optical path; and a second diffraction element for diffracting the light emitted from at least one coherent light source among the at least two coherent light sources so that the center axes of the optical propagation paths of the lights emitted from the respective coherent light sources intersect at one point on the first diffraction element, and wherein said second diffraction element is further provided with a lens function, and said second diffraction element condenses the respective lights emitted from the at least two coherent light sources so that the respective lights diffracted by the second diffraction element irradiate the same region of the first diffraction element.