Patent ID: 6239917
Filing Date: 2001-05-29
Classification: G02B,G03B

Abstract:
A projection lens apparatus, comprising:a front lens unit;a back lens unit optically coupled to the front lens unit;a linear reflecting polarizer optically coupled to the front lens unit and the back lens unit that receives illumination light and directs the illumination light to the back lens unit; andan imager optically coupled to the back lens unit that receives the illumination light, imparts an image onto the illumination light, and directs the image light back to the lens unit, linear reflecting polarizer and front lens unit, wherein the front lens unit and the back lens unit comprise a collective lens system that comprises:a plurality of substantially spherical lens elements; andat least one aspheric lens element aligned along an optical path with the plurality of substantially spherical lens elements, wherein an optical power of the lens system predominantly resides in the plurality of substantially spherical lens elements thereby reducing possible detrimental thermal effects in the projection lens apparatus.