The design of critical automotive lamp reflectors, e.g. headlamps and fog lamps, is dominated by trial-and-error methods and rules-of-thumb, supported by optical ray-tracing tools like ASAP etc. In many cases these reflectors are designed by aiming small sections to construct the required illumination distribution, which is a time-consuming task and in which case it is very difficult to maintain a continuous reflector surface. The design method presented here is a more structured approach in which the total available front surface is divided in a few relatively large sections, each section designated to produce a certain part of the required light distribution. An optimizing algorithm is used to optimize the separate
polynomial reflector sections in combination with a specific burner. In the final step, the separate sections are put together to form a more-or-less continuous reflector surface. Some iteration afterwards is still required because the intersection lines of the polynomial surfaces will generally change the original section boundaries.
The design of a front fog reflector lamp is used as a carrier to demonstrate the approach. Three reflector sections are used to design a high-efficiency fog lamp. The light distribution has an excellent horizontal cut-off that basically meets the SAE requirements.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.