Patent ID: 7777955
Filing Date: 2010-08-17
Classification: G02B

Abstract:
1. An illumination system comprising: a plurality of different light emitting diodes; and a mixer comprising a light pipe having input and output ends and a central region therebetween, an optical path extending in a longitudinal direction from said input end through said central region to said output end, said plurality of light emitting diodes disposed in proximity to said input end wherein at least one of said light emitting diodes is offset from the center of the input end, wherein said central region of said light pipe comprises one or more rippled sidewalls having a plurality of elongate ridges and valleys and sloping surfaces therebetween, at least one ridge or valley of said ridges and valleys at least partially formed by a faceted surface comprising three or more substantially nonorthogonal surface portions or by a rounded surface, wherein light from said plurality of light emitting diodes propagating along said optical path reflects from said sloping surfaces and is redirected at a different azimuthal direction toward said output end thereby mixing and increasing uniformity of said light at said output end.