title: Freeform lens design for LED collimating illumination.
abstract: We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.
authors.affiliation: Department of Electrical Engineering, National Changhua University of Education, Changhua, Taiwan. jjchen@cc.ncue.edu.tw
authors.forename: Jin-Jia
authors.initials: JJ
authors.lastname: Chen
authors.forename: Te-Yuan
authors.initials: TY
authors.lastname: Wang
authors.forename: Kuang-Lung
authors.initials: KL
authors.lastname: Huang
authors.forename: Te-Shu
authors.initials: TS
authors.lastname: Liu
authors.forename: Ming-Da
authors.initials: MD
authors.lastname: Tsai
authors.forename: Chin-Tang
authors.initials: CT
authors.lastname: Lin
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D007909:Lenses; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D008962:Models, Theoretical; D055095:Optics and Photonics / Q000379:methods*; D013499:Surface Properties