Degradation Mechanism Decoupling of Mid-Power White-Light LEDs by SPD Simulation

Journal article (2016)

Authors

J. Huang Beijing Delft Institute of Intelligent Science and Technology
Dušan S. Golubović Lumileds Commercial (Shanghai) Co., Ltd
S.W. Koh Huawei Technologies Company Ltd.
Daoguo Yang Guilin University of Electronic Technology
Xiupeng Li Philips Lighting
Xuejun Fan Lamar University, State Key Laboratory of Solid State Lighting
Kouchi Zhang Electronic Components, Technology and Materials - EEMCS , Chinese Academy of Sciences
Research Group
Beijing Delft Institute of Intelligent Science and Technology
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Published Date

2016

Language

English

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Research Group

Beijing Delft Institute of Intelligent Science and Technology

Abstract

A degradation mechanism analysis methodology is proposed for the mid-power white-light LED packages in this paper. Based on the degradation data obtained from a series of aging tests that are performed on the individual packaging material, the degradation kinetics of lumen output and spectral power distribution of the LED packages are investigated using optical simulation. As a result, although the reflectivity of the packaging materials decreased severely for the blue lights (i.e., 450 nm), the simulation showed that lights at this wavelength were little absorbed in the LED package. More specifically, it is found that: 1) the degradation of the blue lights is mainly due to blue chip deterioration, while rarely affected by the degradation of the silicone encapsulant and other packaging materials; 2) the degradation of the down-converted lights is significantly attributed to the degradation of the blue chips, the phosphors, the lead frames, and the package housing; and 3) the degradation of the silicone encapsulant contributes about 1.35% to the total lumen degradation within 168 h, while has no more contribution to the lumen degradation with further aging duration. The simulation results have been validated by experiments and successfully applied to the degradation mechanism analysis of LED packages in LM-80-08 tests.