MULTI-SCALE SURFACING ROUGHENING OF OPTOELECTRONIC DEVICES FOR LIGHT EXTRACTION ENHANCEMENT

摘要

A combination of two or more roughening processes, at substantially different scales, is used to roughen an interface surface of a light emitting device. A non-ordered roughening is applied at a relatively large scale, and another roughening, either ordered or non-ordered, is applied at a relatively small scale. The large scale roughening improves light extraction efficiency by providing an increased number of escape cones, at varying angles. The small scale roughening improves light extraction efficiency by scattering the light that strikes the smaller features. The large scale non-ordered roughening improves the light output distribution and may reduce the occurrence of multiple total internal reflections, while preserving a Lambertian-like radiation pattern.