Enhanced light extraction in LEDs through the use of internal and external optical elements

摘要

A light emitting diode, LED, with enhanced light extraction, comprises a p-type layer (14); an n-typc layer (15); and an active layer (13) between the p-typc and n-typc layers. Either one of the p-type or n-type layer is a top layer and the other layer is a bottom layer. A first spreader layer (16) is adjacent to the bottom layer and a second spreader layer (20) is on the top layer. Electrical contacts (18,22) are on at least one of the spreader layers so that a bias applied across the contacts causes the active layer to emit light. A substrate (24) is adjacent to one of the spreader layers. Light extraction structures (26) are integral with the layers and provide surfaces to allow light trapped within the LED to disperse, reflect and/or refract out of the LED.