Optical design of rectangular illumination with freeform lenses for the application of LED road lighting

• Published in: Frontiers of Optoelectronics (Online) Vol. 10; no. 4; pp. 353 - 362
• Main Authors: XU, Chunyun, CHENG, Haobo, FENG, Yunpeng
• Format: Journal Article
• Language: English
• Published: Beijing Higher Education Press 01.12.2017; Springer Nature B.V
• Subjects: Biomedical Engineering and Bioengineering; Computer simulation; Design standards; Electrical Engineering; Engineering; freeform lens design; Illuminance; Illumination; Lenses; Light emitting diodes; light-emitting diodes (LED); Lighting; Luminous intensity; nonimaging optics; Optical design; Organic light emitting diodes; Physics; rectangular illumination; Research Article; nonimaging optics; rectangular illumination; light-emitting diodes (LED); freeform lens design
• ISSN: 2095-2759; 2095-2767
• DOI: 10.1007/s12200-017-0707-7

We present a freeform lens for application to light-emitting diodes （LED） road lighting. We propose a simple source-target luminous intensity mapping method based on Snell＇s law and geometric-optics analysis. We calculated different contours of cross-sections to construct a freeform lens with a smooth surface. The computer simulation results show that the lighting performance of a single freeform lens is not sufficient for road lighting. For the road lamp simulation, we adopted an oval arrangement of freeform lenses on a printed circuit board. In addition, we performed tolerance analysis to determine the tolerance limits of manufacturing and installation errors. A road lamp at a height of 12 m can create rectangular illumination with an area of 40 m ~ 12 m, 69.7% uniformity, and average illuminance of 24.6 lux. This lighting performance can fully comply with the urban road lighting design standard.