Patent ID: 7216986

Claim:
A color separating and mixing element comprising, in its transparent cube, a first optical function surface and a second optical function surface which are unparallel to each other, first and second faces of the cube being respectively taken as light incidence surfaces, third, fourth and fifth faces of the cube being respectively taken as light incidence/output surfaces, and a sixth face of the cube being taken as a light output surface, said first optical function surface having the functions of transmitting first color light in the primary color which is predetermined polarized light and reflecting said first color light in the primary color which differs from said predetermined polarized light by 90° in the direction of polarization, said second optical function surface having the functions of transmitting second color light in the primary color which is predetermined polarized light and reflecting said second color light in the primary color which differs from said predetermined polarized light by 90° in the direction of polarization, and the functions of reflecting third color light in the primary color which is predetermined polarized light-and reflecting said third color light in the primary color which differs from said predetermined polarized light by 90° in the direction of polarization, said first color light in the primary color which is predetermined polarized light incident on the first face of said cube passing through the first optical function surface and being emitted from the third face of the cube, said first color light in the primary color returned after the direction of polarization thereof is rotated by 90° being received in the third face of the cube, and the first color light in the primary color being reflected by the first optical function surface and being emitted from said light output surface, said second color light in the primary color which is predetermined light incident on the second face of said cube passing through the second optical function surface and being emitted from the fourth face of the cube, said second color light in the primary color returned after the direction of polarization thereof is rotated by 90° being received in the fourth face of the cube, and the second color light in the primary color being reflected by the second optical function surface and being emitted from said light output surface, and said third color light in the primary color which is predetermined light incident on the second face of said cube being reflected by the second optical function surface and being emitted from the fifth face of the cube, said third color light in the primary color returned after the direction of polarization thereof is rotated by 90° being received in the fifth face of the cube, and the third color light in the primary color passing through the second optical function surface and being emitted from said light output surface.