Increased Efficiency LED

Abstract

In a semiconductor light emitting diode (LED) a large proportion of the light produced will be internally reflected when it strikes the end face of the LED at a semiconductor-air interface. This is due to the high index of refraction of most LED semiconductor materials. This problem may be partially overcome by modification of the shape of the LED by a reverse taper of the sides of the LED. Light is redirected by the taper to strike the interface at an angle closer to normal. This allows light to exit the LED that would be totally internally reflected in an untapered LED. The novelty of the present invention lies in the tapering of the sides of the LED for increased through transmission of light. Prior art devices have made use surface modifications such as roughening, addition of guiding layers, use of index matching materials and hemispherical shaping of the emitting end of the LED. Current technology LEDs have a transmission efficiency of only a few percent. An increase in this efficiency would be of great value to any technology that makes use of LEDs for light generation. The present invention is related to LAR 1 5050-SB, Collection of Light from Optical Fibers of NA greater than 1.