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Design of fiber optic headlamp systems incorporates coupling between a source and the beam-forming optics. In many situations, the coupling includes a bent section of fiber to minimize the package size of the headlamp system. The bend can introduce changes in the light distribution which impact the headlamp performance. The bent fiber is investigated using state of the art illumination design software. The intensity (angular) distribution, the illuminance (spatial) distribution, and the total flux at the output of the bent fiber are the main performance parameters investigated. In addition, modeling results showing that the illuminance distribution varies as a function of view angle are included. A model that incorporates an attenuation coefficient into the fiber clad is shown to provide excellent agreement with measurements. In addition, a novel method for minimizing the changes in the fiber output with a tight bend is shown.

The development of efficient, multi-output High Intensity Discharge (HID) light sources is important for driving fiber systems in automotive applications, in particular for headlamps. Such systems must collect a large fraction of the light from the HID source while efficiently coupling the light into large core light pipes. An earlier paper [1] showed how multifocus optical systems can efficiently split the light evenly between separate output ports. Multifocus systems were shown to be more efficient than a mixing rod approach, especially for the case of two ports. In the case of dual output systems, many more cases need to be considered. To facilitate the investigation, a state-of-the-art optical analysis/design program was employed to demonstrate the tradeoffs between six different dual focus geometries. A novel dual ellipse approach is presented.

The advent of high brightness instant start metal halide light sources and new low loss, low cost tight pipes makes high efficiency distributed lighting systems for automotive applications possible. In principle one or two such sources in combination with the appropriate light guides and beam forming optics can provide all of a vehicle's lighting functions. A fundamental problem has been uniformly feeding just a few small sized light guides from a single source in a low loss and reproducible manner. This paper describes collection optics that provide the required uniform light delivery while maintaining the high lumen density needed for technologically demanding systems such as head lamps.