Open AccessReliability of point source approximations in compact LED lens designs
Author(s) -
Thøger Kari,
Jesper Gadegaard,
Thomas Søndergaard,
Thomas Garm Pedersen,
Kjeld Pedersen
Publication year - 2011
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.19.0a1190
Subject(s) - lens (geology) , optics , footprint , collimated light , computer science , point (geometry) , reliability (semiconductor) , point source , concentrator , physics , power (physics) , mathematics , laser , paleontology , geometry , quantum mechanics , biology
In many applications, compact concentrator lenses are used for collimating light from LEDs into high output beams. When optimizing lens designs, the LED is often approximated as a point source. At small lens-to-LED size ratios this is known to be inaccurate, but the performance compared to optimizations with more realistic models is rarely addressed. This paper examines the reliability of a point source model in compact lens design by comparing with optimisations that use a factory measured LED ray-file. The point source is shown to cause significant, unnecessary efficiency loss even at large lens sizes, while the use of a ray-file allows for a >55% reduction in the footprint area of the lens. The use of point source approximations in compact lens designs is therefore generally discouraged.