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Proceedings Paper

Foil based optical elements for beam shaping and color homogenization of phosphor converted white LED sources
Author(s): Franz P. Wenzl; Wolfgang Nemitz; Ladislav Kuna; Christian Sommer; Paul Fulmek; Johann Nicolics; Peter Pachler; Hans Hoschopf; Franz Schrank; Gregor Langer; Paul Hartmann
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Paper Abstract

Typically, light emission from light-emitting diodes (LEDs) occurs under a broad range of angles. On the other hand, for a lot of applications a more directed light emission is desired. This can be realized with the use of additional optical elements, like lenses. Still, this may provide some complications in case of light sources consisting of a plurality of individual LEDs, e.g., a panel light, which is expected to illuminate a target area homogenously. Instead of a homogeneous illumination, the use of lenses is prone to give reason for an inhomogeneous light distribution in which the emission from the individual LEDs is easily distinguishable. Therefore, there is a strong request for alternative strategies of beam shaping of LED light in LED-luminaires targeting both on a directed as well as homogeneous illumination of an area. In this contribution we discuss an alternative approach in this regard: Firstly, a collimator is designed, which strongly directs the light emitted from a single LED light source. Subsequently, a foil with an optical structure, that can be fabricated in a cost-effective way by soft-lithography and which diffuses the collimated light again, is applied on the collimator. The optical structure and the respective amount of light diffusion are designed in a way that the desired radiation patterns both from a single as well as a plurality of LED sources can be realized. In addition, we show that the realization of a desired radiation profile is not the only advantage of such an approach. A key benefit of this concept is the possibility to reduce the angle dependent inhomogeneity

Paper Details

Date Published: 25 September 2014
PDF: 7 pages
Proc. SPIE 9190, Thirteenth International Conference on Solid State Lighting, 91900A (25 September 2014); doi: 10.1117/12.2061944
Show Author Affiliations
Franz P. Wenzl, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Wolfgang Nemitz, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Ladislav Kuna, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Christian Sommer, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Paul Fulmek, Technische Univ. Wien (Austria)
Johann Nicolics, Technische Univ. Wien (Austria)
Peter Pachler, Tridonic Jennersdorf GmbH (Austria)
Hans Hoschopf, Tridonic Jennersdorf GmbH (Austria)
Franz Schrank, Tridonic Jennersdorf GmbH (Austria)
Gregor Langer, Austria Technologie & Systemtechnik Aktiengesellschaft (Austria)
Paul Hartmann, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)

Published in SPIE Proceedings Vol. 9190:
Thirteenth International Conference on Solid State Lighting
Matthew H. Kane; Jianzhong Jiao; Nikolaus Dietz; Jian-Jang Huang, Editor(s)

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