Patent ID: 9510416
Filing Date: 2016-11-29
CPC Classification: H05B

Claim Text:
1. A method for controlling an illumination device comprising a plurality of emission light emitting diodes (LEDs) and a photodetector, wherein the method comprises: applying respective drive currents to the plurality of emission LEDs to drive the plurality of emission LEDs substantially continuously to produce illumination; periodically turning the plurality of emission LEDs off for short durations of time to produce periodic intervals; measuring a forward voltage presently developed across each emission LED, one LED at a time, during a first portion of the periodic intervals; and determining, for each emission LED, an expected wavelength value and an expected intensity value corresponding to the forward voltage measured across the emission LED and the drive current currently applied to the emission LED by applying one or more interpolation techniques to a table of stored calibration values correlating wavelength and intensity to drive current at a plurality of different temperatures.