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Proceedings Paper

YAG glass-ceramic phosphor for white LED (I): background and development
Author(s): Shunsuke Fujita; Satoru Yoshihara; Akihiko Sakamoto; Shigeru Yamamoto; Setsuhisa Tanabe
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Paper Abstract

We have developed a Ce:YAG (Y3Al5O12) glass-ceramic phosphor for the white LED. The glass-ceramic phosphor was obtained by a heat treatment of a Ce-doped SiO2-Al2O3-Y2O3 mother glass between 1200°C and 1500°C for the prescribed time of period. We confirmed that, by XRD measurements, only YAG crystal precipitated in the mother glass after the heat treatment. It was shown from SEM observation that the YAG crystals with a grain size of approximately 20μm were uniformly dispersed in the glass matrix. The yellow emission, around 540nm in wavelength, was observed from the glass-ceramic phosphor, when it was excited by a blue LED (465nm). The white light due to the mix of yellow and blue light was observed from the glass-ceramic plate with a thickness of 0.5mm. The YAG glass-ceramic phosphor showed a high-temperature resistance and a good performance in a damp heat test. Moreover, a higher thermal conductivity of 2.18 Wm-1K-1 and bending strength of 125MPa were observed compared with a conventional soda-lime glass or an epoxy resin. In addition, since the YAG glass-ceramic phosphor can be formed in a plate-like shape, there is no need to be sealed in resins for the fabrication of the LED devices. Therefore, it is expected that this newly developed glass-ceramic phosphor is a promising candidate for the realization of resin-free, high-temperature and high-humidity resistant, long-life white LED devices.

Paper Details

Date Published: 14 September 2005
PDF: 7 pages
Proc. SPIE 5941, Fifth International Conference on Solid State Lighting, 594111 (14 September 2005); doi: 10.1117/12.614668
Show Author Affiliations
Shunsuke Fujita, Nippon Electric Glass (Japan)
Satoru Yoshihara, Nippon Electric Glass (Japan)
Akihiko Sakamoto, Nippon Electric Glass (Japan)
Shigeru Yamamoto, Nippon Electric Glass (Japan)
Setsuhisa Tanabe, Kyoto Univ. (Japan)

Published in SPIE Proceedings Vol. 5941:
Fifth International Conference on Solid State Lighting
Ian T. Ferguson; John C. Carrano; Tsunemasa Taguchi; Ian E. Ashdown, Editor(s)

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