Goldeneye patent enhances brightness of LED systems

Goldeneye Inc. has been granted a patent on a technique that will enable the use of LEDs in large area projection displays.

Apr 18th, 2005
Goldeneye, Inc. has announced the issuance of US patent no. 6,869,206 entitled "Illumination systems utilizing highly reflective LEDs and light recycling to enhance brightness". The patent describes a method of fabricating high intensity LED-based light sources, enabling the creation of devices that match the brightness of expensive ultra-high-pressure arc lamps using low-cost, current-generation LEDs.

In Goldeneye's technology, multiple LEDs are combined in a recycling cavity where their individual brightness outputs are enhanced. Normally, the concept of etendue (also known as optical extent or throughput) states that multiple light sources cannot be combined to create output that is brighter than any one individual source.

However, unlike blackbody radiators, LEDs can be fabricated with highly reflective surfaces such that they absorb very little of the light they emit. Using Goldeneye's recycling optical approach these "white body" sources can be additively combined. The result is significant radiance improvement in the output of the source.

The patent describes an LED array placed within a highly reflective cavity. The LED source has a reflecting emitting surface, and the optical system is designed to recycle a portion of the emitted light back to the source and then transmit the remainder of the light to the output aperture. Under certain conditions, the effective luminance of the source as well as the output luminance of the optical system can be higher than the intrinsic luminance of the source in the absence of recycling, a result that is not predicted by the standard etendue equations.

"Implementation of the technology behind this and other patents the company currently has pending will have a major impact on the projection display market," says Bill Livesay, president of Goldeneye. "Besides significantly reducing manufacturing and ownership costs, using LEDs provides for much better color purity than current arc-lamp-based displays."

A big advantage of using LEDs is a 50 fold increase in service life: 500-2000 hours for arc lamps versus as much as 50,000 to 60,000 hours for LEDs. And unlike die-based approaches such as resonant cavity LEDs and laser diodes, Goldeneye's technology is scalable. It also has the added benefits of spectral averaging and redundancy.

Products that leverage this proprietary technology can be used in a wide variety of consumer applications, including front and rear projection TVs, automotive headlights, and general lighting. Presently, Goldeneye is developing sources capable of generating sufficient brightness to potentially replace conventional arc lamps found in current commercial projectors.

Goldeneye describes itself as "a technology foundry" that creates innovations in optics and the solid-state lighting market. The company's principals have generated over 50 issued patents in the fields of micro-optics, displays, semiconductor processing, and electronic packaging. Founded in 2004, Goldeneye, Inc. has already accumulated a large and comprehensive IP portfolio, including ten filings related to solid-state lighting. The company is headquartered in Carlsbad, California.

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