LIGHT EMITTING DIODE HAVING IMPROVED LIGHT EXTRACTION EFFECT

摘要

PROBLEM TO BE SOLVED: To provide a light emitting device having improved light extraction efficiency.

SOLUTION: A light emitting device has a stack of layers including a semiconductor layer with an active region 12. The stack is coupled with an optical element 2 having a refractive index larger than about 1.5, preferably about 1.8 for light radiated by the active region 12. A method for coupling a transparent optical element (for example, a lens or an optical concentrator) with a light emitting device includes a step of increasing a temperature of the optical element and the stack, and a step for applying a pressure for pressing the optical element and the light emitting device together. After a block of an optical element material is coupled with the light emitting device, it can be formed as an optical element. The optical element with a high refractive index can be coupled with the light emitting device, and light extraction efficiency of the light emitting device can be improved by reducing a loss due to total internal reflection.

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