Patent ID: 6123424
Filing Date: 2000-09-26
Classification: G02B,H04N

Abstract:
A projector optical system comprising:an illumination optical system for emitting polarized light as illumination light;a dichroic surface that separates the illumination light into light components of different colors and then directs those light components individually to a plurality of reflection-type display panels each having a polarizing plate on a front surface thereof and that integrates together the light components of different colors reflected from the reflection-type display panels and then emits those light components thus integrated together as projection light; anda projection lens system for displaying an image by projecting the projection light,wherein the dichroic surface is inclined with respect to an illumination principal ray traveling from a beam center of the illumination light emitted from the illumination optical system to centers of the reflection-type display panels, and also with respect to a projection principal ray traveling from the centers of the reflection-type display panels to a center of an aperture stop of the projection lens system,wherein one of the following conditions (1) to (4) is fulfilled:(1/2).multidot.(.theta.si-.theta.sp)<(.theta.-.theta.sp)<(3/2).multidot.(.t heta.si-.theta.sp) (1)(1/2).multidot.(.theta.si-.theta.sp)>(.theta.-.theta.sp)>(3/2).multidot.(.t heta.si-.theta.sp) (2)(1/2).multidot.(.theta.si-.theta.sp)<(.theta.-.theta.sp+90)<(3/2).multidot. (.theta.si-.theta.sp) (3)(1/2).multidot.(.theta.si-.theta.sp)>(.theta.-.theta.sp+90)>(3/2).multidot. (.theta.si-.theta.sp) (4)where.theta. represents an angle (.degree.) that the polarization plane of the illumination light makes with a predetermined reference axis on the dichroic surface;.theta.si represents an angle (.degree.) that an S-polarization plane of the illumination principal ray makes with the predetermined reference axis on the dichroic surface; and.theta.sp represents an angle (.degree.) that an S-polarization plane of the projection principal ray makes with the predetermined reference axis on the dichroic surface.