Patent ID: 9392663
Filing Date: 2016-07-12
CPC Classification: G01R,H05B,Y10S

Claim Text:
1. A method for controlling an illumination device comprising a plurality of emission light emitting diodes (LEDs), 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; measuring a forward voltage presently developed across each emission LED by applying a non-operative drive current to each emission LED, one LED at a time, during the short durations of time the plurality of emission LEDs are periodically turned off; and determining chromaticity values that are expected for each emission LED using the forward voltage measured across each emission LED, the respective drive current supplied to each emission LED, a table of stored calibration values correlating forward voltage and drive current to chromaticity at a plurality of different temperatures, and one or more interpolation techniques.