Abstract

The Fresnel lens is composed of micrometer-sized v-groove structures that determine the maximum illuminance and brightness uniformity of LED-driven flashlights, which are used in high-quality photography. The fabrication quality of the microstructures and the accuracy of the geometrical curvature of the Fresnel lens affect the optical characteristics of the emitted light traveling through the lens, which in turn determines the maximum illuminance and brightness uniformity. This paper presents a systematic design procedure for fabricating the Fresnel lens and investigates the influence of geometrical design and fabrication process on optical performance. The optical analysis was performed using the commercial software TracePro. The results revealed that a small tip radius of the v-groove microstructure facilitates brightness uniformity. Furthermore, both the simulation and the experimental results revealed that Fresnel lenses fabricated through injection molding or injection compression molding have either errors of microstructure height more than 3%–6% or curvature errors higher than 6%, which would affect the optical performance, especially the brightness uniformity.

© 2016 Optical Society of America

All-reflective RGB LED flashlight design for effective color mixing

Hsiang-Chen Wang, Yao-Ting Chiang, Chung-Yi Lin, Ming-Yen Lu, Min Kai Lee, Shih-Wei Feng, and Chie-Tong Kuo
Opt. Express 24(5) 4411-4420 (2016)

Design methodology accounting for fabrication errors in manufactured modified Fresnel lenses for controlled LED illumination

Jongmyeong Shim, Joongeok Kim, Jinhyung Lee, Changsu Park, Eikhyun Cho, and Shinill Kang
Opt. Express 23(15) 19743-19751 (2015)

Elimination of flux loss by optimizing the groove angle in modified Fresnel lens to increase illuminance uniformity, color uniformity and flux efficiency in LED illumination

Byungwook Kim, Minseok Choi, Hokwan Kim, Jiseok Lim, and Shinill Kang
Opt. Express 17(20) 17916-17927 (2009)

Hierarchical-genetic-algorithm-based design of a large scale Fresnel lens for a reading light system with multiple LED sources

Wen-Gong Chen and Chii-Maw Uang
Appl. Opt. 45(30) 7832-7840 (2006)

Optical design and optimization of planar curved LED end-lit light bar

Jyh-Cheng Yu, Zhi-Yao Chen, and Bang-De Kao
Appl. Opt. 53(29) H67-H75 (2014)