CONTROLLED LED LIGHT OUTPUT BY SELECTIVE AREA ROUGHENING

摘要

The surface of a light emitting device is roughened to enhance the light extraction efficiency of the surface, but the amount of roughened area is selected to achieve a desired level of light extraction efficiency. Photo-lithographic techniques may be used to create a mask that limits the roughening to select areas of the light emitting surface. Because the amount of roughened area can be precisely controlled, the light extraction efficiency can be precisely controlled, substantially independent of the particular process used to roughen the surface. Additionally, the selective roughening of the surface may be used to achieve a desired light emission output pattern.