LED illumination system having an intensity monitoring system

摘要

A light source and method for controlling the same is disclosed. The light source includes a first component light source that includes N LEDs, a photo-detector, and a light redirector, where N>1. Each LED has a light emitting chip in a package. The light emitting chip emits light in a forward direction and light in a side direction. The light generated in the forward direction is determined by a drive signal coupled to that LED. A portion of the light in the side direction leaves the package. The light redirector is positioned such that a portion of the light in the side direction that leaves the package of each of the LEDs is scattered onto the photo-detector. The photo-detector generates N intensity signals, each intensity signal having an amplitude related to the intensity of the light emitted in the side direction by a corresponding one of the LEDs.