Patent ID: 7511889
Filing Date: 2009-03-31
Classification: G02B,H04N

Abstract:
1. A color separation/combination prism comprising four prism members, wherein the color separation/combination prism includes at least five optical surfaces as outer surfaces thereof, wherein each of the prism members has at least three optical surfaces including two optical surfaces which intersect orthogonally with each other at a first side thereof, wherein the four prism members are joined together such that the first sides of the prism members are adjacent to or contact each other, wherein joining portions of the four prism members are provided with wavelength-selective polarizing films, wherein the positional relationship between the five optical surfaces coincides with the positional relationship between five of eight surfaces of an octahedron that is defined as a three-dimensional shape with an outer surface consisting of eight isosceles triangles having an identical shape, wherein the color separation/combination prism includes an entrance surface for entrance of light from an illumination system, an emergence surface for emergence of light toward a projection system, and three transmission surfaces which serve as surfaces for image-forming elements, and wherein the entrance surface and the emergence surface are arranged on two surfaces of the octahedron, the two surfaces being located on one of two sides of a square surface which includes bases of the eight isosceles triangles of the octahedron, and the three transmission surfaces are arranged on three surfaces of the octahedron, the three surfaces being located on the other side of the square surface.