the omni-directional mirror has been seen before, in several variations, here is one from Epistar Corporation, Hsinchu, Taiwan.
http://www.compoundsemiconductor.net/articles/magazine/9/12/4/1
What makes his different, is his 99% reflection. There are several folks already employing the technique, but not up at the 99% level.
Oriol is an example, who utilized several layers of reflecting metal in their Gigabright line. Not sure if they got their patent yet or not.
Someone even did a Bragg reflector based design:
The design, fabrication, and performance characteristics of a back-surface distributed Bragg reflector (DBR) enhanced InGaN/GaN light-emitting diode (LED) are described. A wide reflectance bandwidth in the blue and green wavelength regions is obtained using a double quarter-wave stack design composed of TiO2 and SiO2 layers. More than 65% enhancement in extracted light intensity is demonstrated for a blue LED measured at the chip level. Similar improvement in green LED performance is discussed and achieved through simulation. Possible applications of back-surface DBR-enhanced LEDs include surface-mount packages with significantly reduced vertical profiles, resonant cavity LEDs, and superluminescent diodes.
—Department of Electrical and Computer Engineering, University of California, Irvine, CA 92697.
—AXT Optoelectronics, Monterey Park, CA 91754.
Dec 8, 2002
A more compact, low profile solution that promises even higher extraction efficiency is to use a mirror deposited directly on the back surface of the chip. Additionally, this Dielectric multilayer mirrors can be designed to provide >99% reflectance over a relatively broad wavelength range, have negligible adsorption in the blue-green wavelength region, and exhibit good adhesion to sapphire.