Abstract:
We have measured five major mechanisms that govern light-emitting diode (LED) degradation, calculated respective percentages, and identified the most influential mechanis...View moreMetadata
Abstract:
We have measured five major mechanisms that govern light-emitting diode (LED) degradation, calculated respective percentages, and identified the most influential mechanism during the time evolution of aging. After 480 h, due to the reduction of phosphor-conversion efficiency, the increase of non-radiative centers, the deterioration of thermal properties, the darkening of silicone resin lenses, and the degradation of Ag reflective layers, approximately 42% of the average optical power has decayed. Within this 42%, Ag degradation contributes approximately 28% (with the remaining 14% contributed by the degradation of silicone resin lenses), primarily because other chemical elements have deposited on the surface of Ag reflective layers, thus lowering the reflectivity of these layers. The present work can help draw the community's attention to lowering LED junction temperatures, and to the optimization of packaging designs.
Published in: IEEE Transactions on Reliability ( Volume: 65, Issue: 1, March 2016)