Mercury-free automotive discharge lamps

Mercury-free HID lamps are currently under investigation for front lighting application in the automotive industry. Besides European legislation aiming at a total removal of hazardous components - such as mercury - in cars, environmentally friendly products are requested by the market. The work presented here is based upon a collaboration between industrial and university partners aiming at a characterisation of properties of mercury-free metal halide lamps in quartz envelopes. The physical and chemical aspects of such lamps, i.e. light technical and electrical lamp data, are studied. The results show that a replacement of mercury in automotive headlight lamps is possible using standard reflectors without significant changes in beam patterns. The main difference to mercury containing lamps observed up to now is a lower lamp voltage in the order of 40-50 V instead of 80-90 V. Light technical data of standard Na/Sc lamps are realised in mercury-free discharges. The project is supported by the German government (BMBF) under contract no. 13N8072 and 13N8264.