Goldeneye sets brightness benchmark for green LEDs

May 15, 2008
Light recycling has enabled Goldeneye to build high performance green LEDs and projection light sources.
Green LEDs have typically been a limiting factor in making high-brightness LED-powered projectors. However, Carlsbad, CA-based Goldeneye says that it has demonstrated LED projection light sources that deliver 300 lumen/mm2 in the green wavelength at a drive current of only 1 amp per mm2.

Goldeneye’s complete three-module RGB units use the company’s patented light recycling technology to produce over 1720 lumens from a 4 mm2 emitting area. The combined RGB “white” output is over 430 lumens per mm2, which Goldeneye claims is an industry record.

“This is nearly double the brightness of any competing LED source,” said Goldeneye CEO Bill Livesay. “This technology now enables projectors with outputs of 1000 on-screen lumens.”

The light sources, which the company is now sampling to select customers, are more collimated than a lambertian emitter, enabling them to couple more efficiently into projector light engines.

In conventional flat light sources, 30-50% of the light is thrown away when coupling into a light train. Integrated optical elements in the Goldeneye source can provide over 1200 green lumens in an étendue of less than 12 steradian.mm2 with more than 94% of the output contained within a ±45 degree angle.

Goldeneye’s “light recycling” cavities, which form the core of the sources, take advantage of the inherent reflectivity of the LEDs to increase the output while maintaining a smaller emitting area and lower drive currents compared to conventional “flat” light sources.

“With the higher reflectivity of LEDs that are currently available,” says Livesay, “Goldeneye’s advantage over conventional LED flat light sources has doubled.”

Goldeneye says that its light source, when coupled with the company’s patented polarization recycling technology, can be utilized to make ultra-bright LCOS projectors. In addition, the low current requirements of Goldeneye’s light sources, compared to other over-driven LEDs, facilitate smaller packaged LED drivers and more efficient cooling.