Patent ID: 8259238

Claim:
An optical unit comprising: an illumination optics system which outputs substantially white light aligned in a predetermined polarization direction, a light separation optics system which separates the substantially white light into light of three colors R, G, and B, liquid crystal panels for R, G, and B light, respectively, which form R, G, and B optical images by optically modulating polarized R, G, and B light according to a video signal, a photosynthesis prism which optically synthesizes the optical images, and a projection lens which enlarges and projects the synthesized optical images; wherein: a common output polarizing plate for R and G light is disposed on an output side of the photosynthesis prism and only an output polarizing plate for B light is disposed between the liquid crystal panels and the photosynthesis prism, and a color selective polarization rotator which rotates polarization of light of a selected wavelength band is disposed between the photosynthesis prism and the common output polarizing plate.