DocumentCode :
58074
Title :
Ultra-High Thermal-Stable Glass Phosphor Layer for Phosphor-Converted White Light-Emitting Diodes
Author :
Chun-Chin Tsai ; Wei-Chih Cheng ; Jin-Kai Chang ; Li-Yin Chen ; Ji-Hung Chen ; Yi-Cheng Hsu ; Wood-Hi Cheng
Author_Institution :
Dept. of Optoelectron. Eng., Far East Univ., Tainan, Taiwan
Volume :
9
Issue :
6
fYear :
2013
fDate :
Jun-13
Firstpage :
427
Lastpage :
432
Abstract :
A glass phosphor layer with ultra-high thermal stability appropriate for phosphor-converted white light-emitting diodes (PC-WLEDs) is demonstrated. The results showed PC-WLEDs utilizing the high thermal stable glass phosphor maintained good thermal stability in lumen, chromaticity, and transmittance characteristics under the thermal aging condition up to 350°C. This is a considerable high operating temperature for a phosphor layer in the PC-WLEDs. The lumen degradation, chromaticity shift, and transmittance loss in the glass-based PC-WLEDs under thermal aging at 150°C , 250°C , 350°C , and 450°C are also presented and compared with those of silicone-based PC-WLEDs under thermal aging at 150°C and 250°C . The result clearly demonstrated that the glass-based PC-WLEDs exhibited better thermal stability in lumen degradation, chromaticity shift, and transmittance loss than the silicone-based PC-WLEDs. The advantages of glass encapsulation in high-temperature operation of the PC-WLEDs could be explained that the glass transition temperature of the glass phosphor (567°C) was much higher than it of silicone (150°C). The newly developed ultra-high thermal-stable glass is essentially critical to the application of LED modules in the area where the high-power, high-temperature and absolute reliability are required for use in the next-generation solid-state lighting.
Keywords :
ageing; glass transition; light emitting diodes; optical glass; phosphors; silicones; thermal stability; thermo-optical effects; PC-WLED; chromaticity shift; glass encapsulation; glass phosphor layer; glass transition temperature; lumen degradation; next-generation solid-state lighting; phosphor-converted white light-emitting diodes; reliability; silicone; temperature 150 degC; temperature 250 degC; temperature 350 degC; temperature 450 degC; temperature 567 degC; thermal aging; transmittance loss; ultrahigh thermal stability; Aging; Educational institutions; Glass; Light emitting diodes; Phosphors; Propagation losses; Thermal stability; Chromaticity shift; glass phosphor; lumen degradation; transmittance loss;
fLanguage :
English
Journal_Title :
Display Technology, Journal of
Publisher :
ieee
ISSN :
1551-319X
Type :
jour
DOI :
10.1109/JDT.2012.2229258
Filename :
6461974
Link To Document :
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