Abstract

We propose a train headlamp system using dual half-circular parabolic aluminized reflectors. Each half-circular reflector contains five high-efficiency and small-package light-emitting diode (LED) chips, and the halves are 180° rotationally symmetric. For traffic safety, the headlamp satisfies the Code of Federal Regulations. To predict the pattern of illumination, an analytical derivation is developed for the optical path of a ray that is perpendicular to and emitted from the center of an LED chip. This ray represents the main ray emitted from the LED chip and is located at the maximum illuminance of the spot projected by the LED source onto a screen. We then analyze the design systematically to determine the locations of the LED chips in the reflector that minimize electricity consumption while satisfying reliability constraints associated with traffic safety. Compared to a typical train headlamp system with an incandescent or halogen lamp needing several hundred watts, the proposed system only uses 20.18 W to achieve the luminous intensity requirements.

© 2018 Optical Society of America

Optical design of an LED motorcycle headlamp with compound reflectors and a toric lens

Wen-Shing Sun, Chuen-Lin Tien, Wei-Chen Lo, and Pu-Yi Chu
Appl. Opt. 54(28) E102-E108 (2015)

Modular design of the LED vehicle projector headlamp system

Chi-Chang Hsieh, Yan-Huei Li, and Chih-Ching Hung
Appl. Opt. 52(21) 5221-5229 (2013)

High-energy-efficiency optical system for an LED-based headlamp architecture

Aiming Ge, Wei Wang, Zhengqing Du, Peng Qiu, Junwei Wang, and Jinlin Cai
Appl. Opt. 52(34) 8318-8323 (2013)

Design of a high-efficiency LED low-beam headlamp using Oliker’s compound ellipsoidal reflector

Shu-Chun Chu, Po-Yo Chen, Cing-Yi Huang, and Kuo-Chih Chang
Appl. Opt. 59(16) 4872-4879 (2020)

Stacking illumination of a confocal reflector light emitting diode automobile headlamp with an asymmetric triangular prism

Hsi-Chao Chen, Jia-Hao Zhou, and Yang Zhou
Appl. Opt. 56(4) 1087-1093 (2017)