Today's most common approach for solid state lighting relies on the conversion of a portion of the blue light emitted from the LED die by an inorganic phosphor material. Although this concept, at a first glance, seems to be rather simple, the appropriate shape of the color conversion element (CCE) in white LED light sources turns out to have essential significance for the quality of the white light (especially in terms of angular homogeneity). In this contribution we discuss recent developments and novel coating concepts for LEDs that excel in terms of spatial homogeneity of the emission and variability of the color temperature, which on the one hand can be attributed to the application of Silicate based phosphors, a beneficial class of luminescent materials for LED application, and on the other hand on optimized CCE geometries, which were obtained by numerical calculations with the help of state-of-the-art simulation tools.

Date Published: 18 November 2008
PDF: 6 pages
Proc. SPIE 7138, Photonics, Devices, and Systems IV, 71382C (18 November 2008); doi: 10.1117/12.818083

Published in SPIE Proceedings Vol. 7138:
Photonics, Devices, and Systems IV
Pavel Tománek; Dagmar Senderáková; Miroslav Hrabovský, Editor(s)