Open AccessUltra-compact LED lens with double freeform surfaces for uniform illumination
Author(s) -
Shixiong Hu,
Kang Du,
Ting Mei,
Lei Wan,
Ning Zhu
Publication year - 2015
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.23.020350
Subject(s) - optics , nonimaging optics , ray tracing (physics) , lens (geology) , geometrical optics , physics , distributed ray tracing , stray light , gradient index optics , materials science , refractive index
An ultra-compact rotational symmetric lens with double freeform surfaces based on the edge-ray principle is designed in this paper. The lens redistributes light emitting from a Lambertian LED light source to achieve uniform illumination within the target area. The initial design is optimized for optics compactness under structural constraints and illumination requirement using the genetic algorithm. A design for the double-freeform-surface lens with a height of the optics system h = 12.56 mm for a circular LED source with a diameter D = 10 mm is demonstrated for uniform illumination within 45° and thus achieves optics compactness h/D = 1.256, which is half of that achieved by the single-freeform-surface lens. The Monte-Carlo ray-tracing result shows an illumination circular area with a clear cut-off at R = 1000 mm at the target plane in a distance H = 1000 mm. The uniformity within the target illumination area is greater than 0.9 and the light output efficiency is as high as 0.9865.