Patent ID: 8057044
Filing Date: 2011-11-15
Classification: G03B

Abstract:
1. A projection display device for enlarging and projecting an image on an imager onto a projection plane, comprising: a light guiding optical system for guiding illumination light to the imager; a projecting optical system for enlarging and projecting modulated light modulated by the imager; and a first polarization converting portion, arranged between the imager and the projecting optical system, for converting a polarization direction of the modulated light into a direction radially extending from a center of an optical axis of the projecting optical system, wherein the imager is arranged at such a position that the center of an effective display area thereof is displaced from the center of the optical axis of the projecting optical system, wherein the projecting optical system includes a refracting optical system, and a reflecting optical system for reflecting the modulated light transmitted through the refracting optical system, and the projection display device further includes a second polarization converting portion, arranged between the refracting optical system and the reflecting optical system, for converting the polarization direction of the modulated light in such a manner that the polarization direction of the modulated light is coaxially aligned with a center of an optical axis of the refracting optical system, and wherein the second polarization converting portion includes a second optical element having a plurality of areas formed in a circumferential direction of the second optical element, directions of anisotropic axes in the areas being different from each other among the areas.