Design of a high-efficiency train headlamp with low power consumption using dual half-parabolic aluminized reflectors
Journal
Applied Optics
Journal Volume
57
Journal Issue
6
Pages
1305-1314
Date Issued
2018
Author(s)
Liang, W.-L.
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.
Other Subjects
Accident prevention; Efficiency; Electric power utilization; Energy efficiency; Light emitting diodes; Reflection; Safety engineering; Circular reflectors; Code of Federal Regulations; Electricity-consumption; High-efficiency; Light emitting diode (LED); Low-power consumption; Luminous intensity; Reliability constraints; Headlights
Type
journal article