Patent ID: 7230222

Claim:
A light source comprising: a substrate; a plurality of dies mounted on said substrate said dies being encapsulated in a transparent cap comprising a layer of material that extends around all of said dies, each die comprising an LED emitting light having a different spectrum from said other LEDs, each LED generating light of an avenge intensity that is determined by a drive signal connected to that LED; a sensor that generates a plurality of signals, each signal being characterized by a sensor value that is indicative of the intensity of light emitted by a corresponding one of said LEDs and independent of the intensity of light emitted by any other LED in said light source, said sensor comprising at least one photodetector that is encapsulated in said layer of material; and a controller that generates said drive signals and stores a current target value for each LED, wherein said light source operates in a calibration phase and an operation phase, wherein during said operation phase said controller generates said drive signals for each of said LEDs such that said sensor value for that LED matches said stored current target value for that LED, and wherein during said calibration phase, said controller stores said current target values.