Dresden 2017 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 14: Various Topics II
DF 14.5: Vortrag
Mittwoch, 22. März 2017, 16:40–17:00, GER 37
Luminescent glasses for LED lighting — •Juliane Schuppich1, Peter W. Nolte2, Franziska Steudel2, and Stefan Schweizer1,2 — 1South Westphalia University of Applied Sciences, Luebecker Ring 2, 59494 Soest — 2Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Luebecker Ring 2, 59494 Soest
Light emitting diodes (LEDs) are currently revolutionizing the lighting market. White LEDs are commonly realized by a blue emitting LED chip combined with a yellow emitting phosphor powder embedded in an organic polymer on top of the chip. However, the polymers are prone to aging due to high temperatures and high light intensities. This work describes an approach to replace the powder/polymer composite by a luminescent glass which offers a significantly higher thermal and chemical stability. Luminescent glasses have attracted much attention in the last decades, in particular for applications such as lasers, optical fibres, and optical amplifiers. Glass is very versatile and a good host for luminescent lanthanide ions; it provides high optical transparency, good lanthanide ion solubility, and it can be cast in almost any shape or size. Here, investigations performed on a blue LED covered with luminescent borate glass are presented. The glasses are analyzed for their optical parameters such as transmittance, reflectance, and quantum efficiency to provide a basis for subsequent optical simulations. The simulations are compared to photometric far-field measurements of the luminous intensity distributions and discussed in detail.