U.S. Patent No. 7,915,624, issued on March 29, 2011 to Lightwave Photonics, Inc. of Encinitas, CA, discloses an epitaxially-grown LED having its active region in proximity to an antinode between two mirrors.
According to the ’624 patent, standard Group III-nitride (e.g., GaN) semiconductor LEDs suffer from low light extraction efficiencies due to the reflections at the semiconductor/air interface. The LED structure disclosed by the ’624 patent has its active region at an antinode (e.g., maximum) of the standing optical wave in the resonant cavity between an epitaxially-grown metal mirror and another mirror. This structure is advantageously “less process intensive and more easily commercialized” than conventional LED structures, and can avoid various problems, such as defects and cracks.
According to its website, Lightwave Photonics is “an early stage Light Emitting Diode (LED) Chip company” developing “proprietary and patent pending technology for low cost ultra high brightness green, blue and white LEDs.” The company has received funds from the California Energy Commission to develop its technology, including $95,000 received in 2010 to study increasing the light extraction efficiency for LEDs while reducing manufacturing costs and $200,000 received in 2009 as part of the American Recovery and Reinvestment Act. The company owns two U.S. patents, including the ’624 patent, according to the USPTO database.