Patent ID: 8998468
Filing Date: 2015-04-07
Classification: A61B,F21V,G02B

Abstract:
1. An illumination system, comprising: a plurality of LED light sources, wherein each of the plurality of LED light sources emits output light of a different color than each other of the plurality of LED light sources; an LED control circuit which controls the electrical power provided to the plurality of LED light sources such that intensity of light emitted by each of the plurality of LED light sources can be varied over a range; associated optics, wherein the associated optics combine the output light of different colors emitted by the first plurality of LED light sources into a combined output light having a combined spectral power distribution; a first optical attenuator interposed between a first LED light source of the plurality of light sources and the associated optics such that output light of said first LED light source is attenuated prior to combination by the associated optics; and a second optical attenuator interposed between a second LED light source of the plurality of light sources and the associated optics such that output light of said second LED light source is attenuated prior to combination by the associated optics; whereby the combined output light has an intensity which can be varied over a desired range without substantially varying the combined spectral power distribution of the combined output light.