The technology of high-power light-emitting diodes (LEDs) is mature. In this study, the LEDs were aged through high temperature to understand the packaging failure mechanisms under lasting lighting. The Tracepro optics simulation software is also applied to analyze the radiation pattern decay caused by curvature variation and material aging.
In the experiment procedure, the LEDs of three manufactures were placed in aging ovens in three different temperatures set at 95¢J, 85¢J, and 65¢J. The experiment results showed that the LED failures were the lens and silicon gel yellowing, silicon gel carbonization, lens slightly chapping, silicon cracks, bubbles generated between lens and silicon gel, and chip damage induced reverse current increase during the aging experiment. We observed the failure mechanism in reduction of optical power at 90%, 80%, 70%, 60%, 50% original power. Furthermore, the failure mechanisms of different from the manufactures is also compared in this work. The LED packages have long lifetime without silicon gel carbonization.
In simulation study, a gap of lens deformation showed a reduction at -60¢X~-40¢X and 40¢X~60¢X of the radiation pattern. The LED modules also showed that the silicon gel and PC absorption coefficient increased. Material absorption coefficient increased more in the short wavelength showed 149mcd at ¡Ó60¢X of the radiation pattern.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0715108-170323 |
| Date | 15 July 2008 |
| Creators | Lo, Yuan-Tsun |
| Contributors | Yan-Kuin Su, Yi-Cheng Hsu, Jao-Hwa Kuang, Wood-Hi Cheng, Mei-Ying Chang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0715108-170323 |
| Rights | not_available, Copyright information available at source archive |
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