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Increased Efficiency LEDIn 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.
Document ID
19960033283
Acquisition Source
Langley Research Center
Document Type
Other - Patent Application
Authors
Egalon, Claudio Oliviera
(Analytical Services and Materials, Inc. Hampton, VA United States)
Rogowski, Robert S.
(NASA Langley Research Center Hampton, VA United States)
Date Acquired
August 17, 2013
Publication Date
April 23, 1996
Subject Category
Electronics And Electrical Engineering
Report/Patent Number
NAS 1.71:LAR-15184-1-SB
Patent Number: NASA-Case-LAR-15184-1-SB
Report Number: NAS 1.71:LAR-15184-1-SB
Patent Application Number: US-Patent-Appl-SN-644654
Accession Number
96N30083
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
NASA-Case-LAR-15184-1-SB
Patent Application
US-Patent-Appl-SN-644654
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