Comparison of Dual Focus Collector Schemes for Fiber Systems

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.