Patent ID: 7631972

Claim:
A wavelength-selective polarization conversion element which converts non-polarized light containing light in a first wavelength region, light in a second wavelength region, and light in a third wavelength region into polarized light, comprising: a polarization beam splitting film which has a function of splitting light through transmission and reflection and has a characteristic in which each of the transmittance for light with a first polarization direction and the transmittance for light with a second polarization direction orthogonal to the first polarization direction is changed between a value higher than 50% and a value lower than 50% depending on the wavelength region; and a phase plate which changes the polarization direction of light transmitted or reflected by the polarization beam splitting film between the first polarization direction and the second polarization direction, wherein the polarization conversion element causes light in two of the first, second and third wavelength regions to emerge as polarized light with one of the first and second polarization directions and causes light component in the other one of the first, second and third wavelength regions to emerge as polarized light with the other of the first and second polarization directions.