e-journal

Thermal-Stability Comparison of Glass- and Silicone-Based High-Power Phosphor-Converted White-Light-Emitting Diodes Under Thermal Aging

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The lumen degradation, chromaticity shift, transmittance loss, and mean-time-to-failure (MTTF) evaluation in
glass- and silicone-based high-power phosphor-converted whitelight- emitting diodes (LEDs) (PC-WLEDs) under accelerated thermal aging at 150 ◦C, 200 ◦C, and 250 ◦C are presented and compared. The silicone-based PC-WLEDs exhibited less thermal stability than the glass-based PC-WLEDs by 1.86, 2.79, and 4.76 times higher lumen losses, 3.05, 3.26, and 6.84 times larger chromaticity shifts, and 1.82, 2.62, and 6.67 times greater transmittance losses at 150 ◦C, 200 ◦C, and 250 ◦C, respectively. The results also showed that the glass-based PC-WLEDs exhibited higher MTTF than the silicone-based PC-WLEDs by 20 times at room temperature. The peaks of the emission and excitation spectra for both silicone and glass phosphors were not significantly
changed after thermal aging, evidenced by fluorescence spectrophotometer analyses. This indicated that the fluorescent ability of Ce:YAG-doped phosphor materials did not change after thermal aging and the transmittance loss was corresponding to the lumen loss and chromaticity shift. The results of the lumen loss,
chromaticity shift, transmittance loss, and MTTF investigations clearly demonstrated that the thermal-stability performance of the glass-based PC-WLEDs was better than that of the silicone-based PC-WLEDs. The advantage of employing doped glass encapsulation in high-power PC-WLEDs could be explained: The material
property of glass transition temperature of 750 ◦C was higher than that of silicone transition temperature of 150 ◦C. A better thermal stability phosphor layer of glass as encapsulation material may be beneficial to many applications where the LED modules with high power and high reliability are demanded for use in next-generation solid-state lighting.

Index Terms—Aging test, high-power light-emitting diodes (LED) modules, phosphor layer.

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Ketersediaan

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Informasi Detail

Judul Seri

IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY

No. Panggil

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Penerbit

New York : IEEE., 2014

Deskripsi Fisik

IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY, VOL. 14, NO. 1, MARCH 2014

Bahasa

English

ISBN/ISSN

DOI: 10.1109/TDMR.20

Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

VOL. 14, NO. 1, MARCH 2014

Subjek

ELEKTRONIK

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

Versi lain/terkait

Lampiran Berkas

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