The impact of the thermal conductivities of the color conversion elements of phosphor converted LEDs under different current driving schemes

• Published in: Journal of luminescence 2016-01, Vol.169, p.559-568
• Main Authors: Fulmek, Paul, Nicolics, Johann, Nemitz, Wolfgang, Schweitzer, Susanne, Sommer, Christian, Hartmann, Paul, Schrank, Franz, Wenzl, Franz P.
• Format: Article
• Language: English
• Subjects: Color conversion; Optical simulation; Phosphor; Solid state lighting; Thermal simulation
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2015.04.003

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 thermal conductivities of the color conversion elements (CCE) of phosphor converted LEDs on their respective thermal load for different current driving schemes. In particular we show that, while for the thermal load of CCEs with low thermal conductivities also effects due to the non-linearity between the blue radiant flux and the current have to be considered, these effects are largely diminished in case of CCEs with higher thermal conductivities. •We discuss the thermal load of phosphor based LEDs for different current driving.•We report on the time scales for the thermal load of phosphor based LEDs.•We report on the impact of the non-linearity of the radiant flux on the thermal load.•We discuss the impact of the thermal conductivity on the thermal load.