Open AccessThe impact of the non-linearity of the radiant flux on the thermal load of the color conversion elements in phosphor converted LEDs under different current driving schemes
Author(s) -
Franz P. Wenzl,
Christian Sommer,
Paul Hartmann,
Peter Pachler,
Hans Hoschopf,
Gregor Langer,
Paul Fulmek,
J. Nicolics
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.00a439
Subject(s) - radiant flux , light emitting diode , phosphor , duty cycle , optics , materials science , diode , linearity , luminous flux , thermal , optoelectronics , color temperature , current (fluid) , voltage , physics , electronic engineering , electrical engineering , engineering , light source , meteorology
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.