Patent ID: 7273279

Claim:
A projection display apparatus comprising: a light source which emits an indefinitely polarized light; first to third reflection type spatial light modulation elements that light-modulate three primary color lights obtained by subjecting the indefinitely polarized light to color separation; first wavelength selective polarization converting means for separating the indefinitely polarized light emitted from the light source into a first color component light having a first polarized wave surface and second and third color component lights having a second polarized wave surface as another polarized wave surface different from the first polarized wave surface by 90 degrees, and emitting the separated color component lights; a first polarization split element that receives a light beam transmitted through the first wavelength selective polarization converting means and divides the light beam into the first color component light and the second and third color component lights; second wavelength selective polarization converting means for receiving the second and third color component lights from the first polarization split element and emitting the second color component light and the third color component light in a state where the polarized wave surface of the second color component light and the polarized wave surface of the third color component light are orthogonal to each other; a second polarization split element that has a polarization split surface that receives the second and third color component lights from the second wavelength selective polarization converting means, the polarization split surface transmitting the second color component light therethrough so that the second color component light enters the second reflection type spatial light modulation element set with a first distance from the polarization split surface, and reflecting the third color component light so that the third color component light enters the third reflection type spatial light modulation element set with a second distance from the polarization split surface, the second distance being different from the first distance; a polarization combining element that receives modulated lights modulated by the first to third reflection type spatial light modulation elements, combines the modulated lights and emits the combined lights; and a projection lens that has an axial chromatic aberration corresponding to a difference between the first distance and the second distance, wherein an axial chromatic aberration ΔL of the projection lens is constituted to have a relationship of 20 μm <ΔL=|fb 1 -fb 2 |≦70 μm, in which fb 1 is a back focal distance of the projection lens with respect to a central wavelength λ 1 of the second color component light that enters the second reflection type spatial light modulation element, and fb 2 is a back focal distance of the projection lens with respect to a central wavelength λ 2 of the third color component light that enters the third reflection type spatial light modulation element.