New Reflection-Type Xenon Headlamps Using HID Technology

Since the very first series introduction of a HID Litronic headlamp in 1991 by Bosch, almost all vehicles have been equipped with the projector headlamp technology, utilizing the D1 and later-on the D2S discharge bulbs. These bulbs need some additional measure to provide for good contrast and thus for good control of the glare values. With a projector headlamp this measure is accomplished via the system-inherent shield, yielding an excellent control of the cut-off line both for ECE and SAE beam patterns.

In this paper, newly developed headlamps of the projection- and reflection-type from Bosch and Mercedes-Benz will be presented. Due to the ongoing development of the discharge bulbs the D2R bulb is now available. This bulb which has been specifically designed for reflection type headlamps incorporates accurately adjusted shielding stripes on the outer glass jacket of the bulb. These shielding stripes provide for a cut-off line as well defined as with the projector headlamp technology, even with different headlamp designs for ECE and SAE beam patterns. The HID technology allows for a superior qualify in light output and light distribution with projection as well as with new reflection type headlamps. This will be demonstrated in comparison to high performance headlamps with halogen bulbs.