Optical Design of Direct Projection Bicycle Light

Optical lighting systems usually demand specific illuminance distributions to comply with regulatory requirements for various applications. This study demonstrates an optical design of bicycle light integrated with a special Fresnel lens and a reflector. To enhance the light intensity, the proposed bicycle light adopts direct projection rather than reflection. The Fresnel lens is used to concentrate light and achieve the specific distribution of illuminance. The reflector provides a parabola reflective surface and reduces the divergence of light to greatly cast out parallel light, which improves the illuminance. For optimum case, the simulation is based on the total LED power of 180 lm, and the optical power is analyzed as 85 lm with a distance of 10 m away from the bicycle light. The illuminance distribution of bicycle light and cut-off line can meet the requirements of German StVZO regulations.