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Optics Express, Vol. 21, Issue S3, pp. A439-A449 (2013).
Franz P. Wenzl, Christian Sommer, Paul Hartmann, Peter Pachler, Hans Hoschopf, Gregor Langer, Paul Fulmek, and Johann Nicolics.
Institute of Surface Technologies and Photonics, Joanneum Research Forschungsges.mbH, Franz-Pichler-Straße 30, A-8160 Weiz, Austria and
Tridonic Jennersdorf GmbH, Technologiepark 10, A-8380 Jennersdorf, Austria and
Austria Technologie & Systemtechnik AG, Fabriksgasse 13, A-8700 Leoben, Austria and
Institute of Sensor & Actuator Systems, Vienna University of Technology, Gusshausstraße 27-29, A-1040 Vienna, Austria.
Abstract
For a systematic approach to improve the reliability and the white light quality of phosphor converted light-emitting diodes (LEDs) it is imperative to gain a better understanding of the individual parameters that affect color temperature constancy and maintenance. By means of a combined optical and thermal simulation procedure, in this contribution we give a comprehensive discussion on the impact of different current driving schemes on the thermal load of the color conversion elements (CCEs) of phosphor converted LEDs. We show that on the one hand a decreasing duty cycle under pulse width modulation driving conditions may cause a notable temperature variation and on the other hand also effects due to the non-linearity between the blue radiant flux and the current have to be considered for the thermal load of the CCEs.
© 2013 OSA
