Patent ID: 7255444
Filing Date: 2007-08-14
Classification: G03B

Abstract:
1. A projection type image display apparatus comprising: a polarization split device arranged to receive incoming light, the polarization split device producing polarized light; a light valve to produce modulated light, the light valve having an incident surface upon which the polarized light from the polarization split device is incident; a projection lens disposed along an optical path of the light valve to enlarge and project light emanating from the light valve; and a drive circuit to drive the light valve according to a video signal, the polarization split device comprising a first medium to receive the incoming light, an emitting surface from which emitted light emanates, and a diffractive grating having a first surface on which the emitted light is incident and from which light is reflected to produce the polarized light, the first surface being exposed to a second medium that is different from the first medium, wherein the first medium is a transmissive liquid, the polarization split device further comprising a pair of spaced apart transmissive plates disposed in the transmissive liquid, the space between the transmissive plates being absent of the transmissive liquid, wherein the diffractive grating is disposed on one of the transmissive plates.