Patent ID: 7472995

Claim:
A wavelength-selective polarization conversion element which converts non-polarized light including light of a first wavelength region, light of a second wavelength region and light of a third wavelength region into polarized light, the element comprising: a beam splitting film which splits light by transmission and reflection and has a characteristic in which at least its transmittance for light with a first polarization direction changes between a transmittance higher than 50% and a transmittance lower than 50% depending on wavelength regions; and a phase plate which converts, when transmitting once therethrough the light of the first wavelength region, the light of the second wavelength region and the light of the third wavelength region, a second polarization direction orthogonal to the first polarization direction and the second polarization direction thereof into the first polarization direction, wherein the polarization conversion element converts light of two of the first, second and third wavelength regions into light with one of the first and second polarization directions and converts light of the remaining one wavelength region into light with the other polarization direction, and wherein the beam splitting film and the phase plate are formed integrally with each other.