Patent ID: 6885403

Claim:
A color separation beam splitter for projectors comprising a plurality of prisms connected with each other and three optical interference filters having different wavelength ranges respectively formed on side surfaces of the plurality of prisms, wherein the color separation beam splitter is characterized in that the three optical interference filters include a yellow color reflective dichroic mirror which reflects pure yellow light and passes red light, blue light and green light; a red color reflective dichroic mirror which reflects pure red light and passes green light and blue light; and a blue color reflective dichroic mirror which reflects pure blue light and passes pure green light, so that when a white light is incident to the color separation beam splitter, a yellow light is first reflected by the yellow color reflective dichroic mirror, a red light is then reflected by the red color reflective dichroic mirror, and then a blue light and a green light are split by the blue color reflective dichroic mirror.