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Proceedings Paper

Prediction of light extraction efficiency of LEDs by ray trace simulation
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Paper Abstract

The advantage of enhancing the light extraction of LED dies is twofold: it increases the overall efficiency of the device, reducing internal absorption and subsequently the temperature of the device. We have developed the solid model of a commercially available blue LED in a ray tracing simulation software according to the physical structure of the GaN die grown on SiC substrate. Optical parameters of the various device layers were adjusted within a plausible range to achieve the best match between the measured and the simulated spatial luminous intensity profile. Two approaches for improving the light extraction efficiency were examined using the model: change of refractive index of the encapsulating medium and chip shaping. Simulation results were verified by a series of luminous intensity and total flux measurements in a mini-goniophotometer. We found that the physical experiment confirmed the predicted results.

Paper Details

Date Published: 26 January 2004
PDF: 8 pages
Proc. SPIE 5187, Third International Conference on Solid State Lighting, (26 January 2004); doi: 10.1117/12.504935
Show Author Affiliations
Akos Borbely, Lawrence Berkeley National Lab. (United States)
Steve G. Johnson, Lawrence Berkeley National Lab. (United States)

Published in SPIE Proceedings Vol. 5187:
Third International Conference on Solid State Lighting
Ian T. Ferguson; Nadarajah Narendran; Steven P. DenBaars; John C. Carrano, Editor(s)

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