In this letter, we present a new design for a light-emitting diode-based bike headlamp. The optical design contains two horizontal reflectors and a light pipe with two horizontal parallel mirrors. The designed illumination pattern in our simulations performs a contrast of 250 in the K-mark regulation, and it was measured to be 21 in the experiment with a not well-finished prototype, which was operated at 1 W. The contrast is higher than 5 as requested in the regulation. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3615278]
