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NCUEIR > College of Engineering > Department and Graduate Institute of Electronic Engineering > Periodical Articles > Item 987654321/10850

Please use this identifier to cite or link to this item: http://ir.ncue.edu.tw/ir/handle/987654321/10850

Title:	Freeform Surface Design for a Light-Emitting-Diode-Based Collimating Lens
Authors:	Chen, Jin-Jia;Lin, Chin-Tang
Contributors:	電機工程學系
Keywords:	Collimating lens;Freeform surface;Light-emitting diode;Total internal reflection surface
Date:	2010-09
Issue Date:	2012-06-04T08:35:32Z
Publisher:	SPIE
Abstract:	A freeform collimating lens is designed to project light rays emitted from an LED light source to a far target plane. Generally, the projection distance is assumed to be more than 100 m, and the light beam to have negligible divergence. The lens consists of a total internal reflection TIR side surface, a spherical surface in the rear, a vertical plane surface in the outer part of the front, and a freeform refractive surface in the central part of the front. Light rays emitted from the LED source with large spread angles hit the TIR surface and are redirected parallel to the light axis, and those having small spread angles will be collimated by the freeform refractive surface, which is designed with a simple approximation method, and then travel parallel to the light axis. Computer simulation results show that an optical efficiency of 81.5% is achieved under a view angle of �5 deg and for a 1 mm 1 mm LED source.
Relation:	Optical Engineering, 49(9): 093001
Appears in Collections:	[Department and Graduate Institute of Electronic Engineering] Periodical Articles

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