Koninklijke Philips Corporation N.v.

Frank J P Schuurmans

Michael D Pashley

Thomas M Marshall

According to this invention, a side-emitting illumination device for uniformly distributing light is composed of an LED light source, a light-transmitting rod which permits total internal reflection, and outcoupling material affixed to an outer surface of the rod. Light enters the rod at one end and travels along the rod by total internal reflection. Light that hits the outcoupling material is angularly distributed based on the width of the outcoupling material.

Side-emitting rod for use with an LED-based light engine

White light emitting LED luminaire incorporates an array of red, green and blue emitting LEDs and a feedback arrangement to maintain a desired color balance. The feedback arrangement includes photodiodes positioned and enabled to separately measure the light output of each RGB color component. In one embodiment, a single photodiode or array of photodiodes is positioned to intercept reflected light from a partially reflecting element placed in the path of the combined output of the LED array. Individual colors are measured sequentially by pulsing the LEDs and photodiodes or by the use of color filters. In an alternate embodiment, each LED has an associated photodiode, either incorporated into the LED package or in a separate package.

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Valkenswaard, Netherlands

Frank J P Schuurmans