Lumen degradation and chromaticity shift in glass and silicone based high-power phosphor-converted white-emitting diodes under thermal tests

Wood-Hi Cheng; Chun-Chin Tsai; Jimmy Wang

doi:10.1117/12.892546

22 September 2011 Lumen degradation and chromaticity shift in glass and silicone based high-power phosphor-converted white-emitting diodes under thermal tests

Wood-Hi Cheng, Chun-Chin Tsai, Jimmy Wang

Author Affiliations +

Proceedings Volume 8123, Eleventh International Conference on Solid State Lighting; 81230F (2011) https://doi.org/10.1117/12.892546
Event: SPIE Optical Engineering + Applications, 2011, San Diego, California, United States

Abstract

The lumen degradation and chromaticity shift in glass and silicone based high-power phosphor-converted white-emitting diodes (PC-WLEDs) under accelerated thermal tests at 150°C, 200°C, and 250°C are presented and compared. The glass based PC-WLEDs exhibited better thermal stability than the silicone by 4.8 time reductions in lumen loss 6.8 time reductions in chromaticity shift at 250°C, respectively. The mean-time-to-failure (MTTF) evaluation of glass and silicone based high-power PC-WLEDs in accelerated thermal tests is also presented and compared. The results showed that the glass based PC-WLEDs exhibited higher MTTF than the silicone by 7.53 times in lumen loss and 14.4 times in chromaticity shift at 250°C, respectively. The thermal performance of lumen, chromaticity, and MTTF investigations demonstrated that the thermal stability of the glass based PC-WLEDs were better than the silicone. A better thermal stability phosphor layer of glass as encapsulation material may be beneficial to the many applications where the LED modules with high power and high reliability are demanded.

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Wood-Hi Cheng, Chun-Chin Tsai, and Jimmy Wang "Lumen degradation and chromaticity shift in glass and silicone based high-power phosphor-converted white-emitting diodes under thermal tests", Proc. SPIE 8123, Eleventh International Conference on Solid State Lighting, 81230F (22 September 2011); https://doi.org/10.1117/12.892546

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