| 摘要 |
An exemplary system to provide visible lighting of a selectable spectral characteristic (e.g. a selectable color combination of light) uses an optical integrating cavity or other diffuse mixing element to combine light of different colors from different color LEDs. Amplitude modulation of pulsed operation the light sources, e.g. pulse amplitude modulation added to a baseline forward bias current for each of the LEDs, controls the amount of each light color supplied to the diffuse mixing element and thus the amount included in the combined light output of the system. A color sensor may provide feedback as to a color characteristic of the combined light, for closed-loop control of one or more of the pulse amplitude modulations. Examples are also disclosed that utilize phosphor doping of one or more of the system's reflective elements, to add desired wavelengths of light to the combined output.
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