Patent ID: 8038298

Claim:
A projector device comprising: a casing having disposed therein a light source; and an optical system for receiving light from the light source to generate image light, the optical system having disposed on an optical axis thereof: a polarization beam splitter for extracting only a first component wave out of first and second component waves of light vibrating in orthogonal directions, the polarization beam splitter comprising: a polarizing plate, and a half-wavelength plate joined to a light emergence surface thereof, the polarizing plate comprising: a plurality of first interfaces for passing the second component wave therethrough and reflecting the first component wave, and a plurality of second interfaces for reflecting the first component wave reflected by the first interfaces toward a light emergence direction, which are formed alternately in a direction intersecting the optical axis, the polarizing plate having a latter stage slit plate arranged in contact with or close to a light incidence surface thereof, the latter stage slit plate being provided with a plurality of slits at a plurality of locations corresponding to the first interfaces of the polarizing plate, the optical system being provided with a former stage slit plate in a position spaced apart along the optical axis from the latter stage slit plate toward the light source, the former stage slit plate being provided with a plurality of slits at a plurality of locations identically overlapping in width in the optical axis direction with the respective slits of the latter stage slit plate, wherein the former stage slit plate and the latter stage slit plate are fixedly arranged in a setting groove formed on an optical system holding case and comprise a metal material having a coefficient of thermal conductivity higher than that of a material constituting the polarization beam splitter.