New LED structures that provide increased light extraction efficiency while retaining a planar structure.
As semiconductor materials have improved, the efficiency of semiconductor devices has also improved and new wavelength ranges have been used. Gallium nitride (GaN) based light emitters are probably the most promising for a variety of applications. GaN provides efficient illumination in the ultraviolet (UV) to amber spectrum, when alloyed with varying concentrates of indium (In), for example. Unfortunately, most of the light emitted within a semiconductor LED material is lost due to total internal reflection at the semiconductor-air interface. Typical semiconductor materials have a high index of refraction, and thus, according to Snell's law, most of the light will remain trapped in the materials, thereby degrading efficiency. By choosing a suitable geometry for the LED, a higher extraction efficiency can be achieved.
Researchers at the University of California, Santa Barbara have developed new LED structures that provide increased light extraction efficiency while retaining a planar structure. The planar structure makes the new LED structures easy to manufacture and at low cost.
This technology is available for licensing.
|United States Of America||Issued Patent||8,390,011||03/05/2013||2005-145|
|United States Of America||Issued Patent||7,755,096||07/13/2010||2005-145|
LED, photonic crystal, indssl, indled, indphoto, cenIEE, indfeat