US Patent No. 9,175,816

SYSTEM AND METHOD FOR MIXING LIGHT FOR A LED-BASED LINEAR LIGHT SOURCE


Patent No. 9,175,816
Issue Date November 03, 2015
Title System And Method For Mixing Light For A Led-based Linear Light Source
Inventorship Matthew D. Weaver, Aptos, CA (US)
Assignee LUMENETIX, INC., Scotts Valley, CA (US)

Claim of US Patent No. 9,175,816

1. A linear light source comprising:
electronic circuitry to drive light emitting diodes (LEDs);
a plurality of LEDs coupled to the electronic circuitry, the LEDs with more than one color type;
a light pipe positioned to provide total internal reflection (TIR) of light rays emitted from the plurality of LEDs at light
ray angles larger than a critical angle with respect to a normal vector of a surface of the light pipe; and

a shell with a highly reflective inner surface over and along the light pipe, wherein the shell and the highly reflective
inner surface are spaced apart with an air gap from the light pipe and conform to the shape of the light pipe;

wherein the shell has an exit aperture along a pipe axis of the light pipe, wherein the exit aperture is an opening in the
shell and in the highly reflective inner surface along the pipe axis; and

wherein the light pipe has cut outs aligned across from the exit aperture, each of the cut outs having a slanted surface,
wherein the light pipe is a cylinder with an elliptical cross-section having a first focal point and a second focal point,
wherein an interface surface of at least one of the cut outs is aligned to the first focal point.