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Proceedings Paper

Design of compact freeform LED flashlight capable of two different light distributions
Author(s): Annie Shalom Isaac; Cornelius Neumann
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Paper Abstract

Free-form optical surfaces are designed for desired intensity requirements for applications ranging from general to automotive lighting. But a single compact free-form optics which satisfies two different intensity distributions is not presented so far. In this work, a compact LED flashlight fulfilling two different intensity requirements that could be used in potentially explosive atmospheres is designed and validated. The first target is selected after a study on visibility analysis in fog, dust, and smoke environments. Studies showed that a ring-like distribution (5°- 10°) have better visual recognition for short distances in smoky environments. The second target is selected to have a maximum intensity at the peak to provide visibility for longer distances. We realized these two different intensity requirements by moving the LED with respect to the optics along the optical axis. To fulfill the above- required intensity distributions, hybrid TIR optics was designed as free-form curves calculated by combining several geometric optic methods. We validated the free-form TIR hybrid optics using Monte Carlo ray trace simulation. The overall diameter of the optics is 29 mm and 10 mm in thickness. The simulated results showed an optical efficiency of about 84% to realize both target light distributions in a single optics. Then we designed a whole flashlight consisting of LED, PMMA hybrid optics, PC glass casing and a housing including the critical thermal management for explosive environments. To validate the results, a prototype for the designed optics was made. The measured results showed an overall agreement with the simulated results.

Paper Details

Date Published: 27 April 2016
PDF: 7 pages
Proc. SPIE 9889, Optical Modelling and Design IV, 98890X (27 April 2016); doi: 10.1117/12.2227517
Show Author Affiliations
Annie Shalom Isaac, Karlsruher Institut für Technologie (Germany)
Cornelius Neumann, Karlsruher Institut für Technologie (Germany)


Published in SPIE Proceedings Vol. 9889:
Optical Modelling and Design IV
Frank Wyrowski; John T. Sheridan; Youri Meuret, Editor(s)

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