Patent ID: 7852885

Claim:
A light source device, comprising: a light emitting unit that has one or more light emitting element emitting fundamental laser beams in a direction vertical to a light emitting surface; a first optical element that deflects a propagation direction of the fundamental laser beams emitted from the light emitting unit toward a direction substantially parallel to a disposition surface of the light emitting unit; a wavelength converting element that is disposed on an optical path of the fundamental laser beams having passed the first optical element so as to convert at least a portion of the fundamental laser beams into harmonic laser beams; an external resonator that selects the fundamental laser beams among those having passed the wavelength converting element so that the fundamental laser beams selected are reflected toward the first optical element and guided back to the light emitting unit, thereby functioning as a resonator mirror for the light emitting unit, while allowing the harmonic laser beams to pass therethrough; a second optical element that separates those laser beams having passed the wavelength converting element after being reflected from the external resonator into the harmonic laser beams that are converted by the wavelength converting element and the fundamental laser beams; and a third optical element that deflects the propagation direction of the harmonic laser beams that are separated by the second optical element toward a direction substantially parallel to the disposition surface of the light emitting unit, the second optical element being a wavelength separating film, the wavelength separating film having a polarization selecting function for making a ratio of output beams to input beams of the fundamental laser beams different from each other in two polarization components having different polarization directions, and the polarization direction associated with a higher ratio in the polarization selecting function of the wavelength separating film being substantially identical to a polarization direction of the wavelength converting element, the wavelength separating film having a polarization selecting function in which a difference between two polarization components of a fundamental wavelength is greater than a difference between two polarization components of a converted wavelength.