| 摘要 |
An illumination sourceÄ70Ü for use in projectors and the like. The illumination sourceÄ70Ü includes a light sourceÄ71,81Ü that generates a two-dimensional emission pattern having a light intensity that varies as a function of position in the emission pattern. A collectorÄ72,82Ü collects the light from the light sourceÄ71,81Ü and illuminates an exit apertureÄ76Ü therewith. The illuminated exit apertureÄ76Ü has a two-dimensional emission pattern with a light intensity that varies as a function of position in a manner that is more uniform as a function of position than the emission pattern of the light sourceÄ71,81Ü. An imaging optical elementÄ73Ü images the exit apertureÄ76Ü onto a surfaceÄ74Ü. The collectorÄ72,82Ü is preferably a compound parabolic concentrator or a compound elliptical concentrator. In one embodiment of the invention, a partially reflecting filmÄ83Ü is placed between the exit apertureÄ76Ü and the imaging optical elementÄ73Ü. The partially reflecting filmÄ83Ü reflects light of a first polarization state back into the collectorÄ72,82Ü and transmits light of the orthogonal polarization state. In another embodiment of the invention, a quarter wave plateÄ84Ü is introduced between the exit apertureÄ76Ü and the partially reflecting filmÄ83Ü to further increase the radiance of the source. <IMAGE> |
