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Automated Driving Systems (ADS) are now at start to initiate a change of the human mobility and usage of vehicles. The safe and non-disruptive integration of automated vehicles into “normal” traffic will ask for a new way of communication between the vehicles and their environment. Similar to the existing signal lights, dedicated ADS signals can play a major role in this communication, in a passive way e.g. as tail light (to be seen) or in an active mode beyond turn indicators or stop lights. Recent publications show high attention on the automation of vehicles - traffic density as well customer comfort is driving the development towards more autonomy and intense usage of human-machine interfaces to increase effectiveness of transportation. Vehicle lighting in this field will take a natural functionality - both to see and to be seen needs to be updated to the future needs of the application.

In 2004 environmental-friendly mercury free xenon HID lamps - D3 and D4 respectively with and without integrated igniter - were introduced in the automotive headlighting market. Driven by an increased concern for the environment from all stake holders in the car industry mercury free xenon HID has started his successful replacement of mercury containing xenon HID lamps used for automotive head lighting all over the world. Of course, the elimination of mercury was a key factor in promoting the environmental friendliness of xenon HID. Furthermore the amount of radioactive thorium compounds could be reduced to 2% of the content of the D1/D2 bulbs. Since then mercury free bulb designs without any thorium content have been studied assessing the electrical and optical compatibility with existing mercury free system designs.

In recent years environmental-friendly Mercury free Xenon HID lamp - D3 and D4 respectively with and without integrated igniter - were introduced in the automotive headlighting market. This market introduction was primarily driven by an increased concern for the environment by all stakeholders in car industry including the end-users. Furthermore, ordered by public authorities world wide, via new environmental legislation rules, Mercury free Xenon HID lamps will take over an important part of the Xenon HID market in due time. Within this perspective this paper will give an overview about technical backgrounds of Mercury free Xenon HID lamp performance. Next to light technical aspects the electrical interfaces between lamp and electronic driver are included. Furthermore, new developments in terms of satisfying carmakers requests on environmental aspects, electromagnetic compatibility and application flexibility will be discussed.

Mercury containing Xenon HID bulbs are currently on the exemption list of the European End of Life (EoL) Directive for Vehicles [1]. Their usage is generally accepted due to their superior performance and energy efficiency. These lamps also find a wider application in the US, but environmentally cautious states start to require labeling in order to ease dismounting and safe disposal at end of life. The concern for the environment is also the driving force behind the intention of Japanese carmakers to switch over to mercury free alternatives. Under these global boundary conditions the innovation of mercury free Xenon HID headlighting started mid of 2001. This paper gives an overview on the technical background of this breakthrough. From a physical point of view, key elements of environmental-friendly design of HID bulbs and its application in car headlighting will be described. We will also address the merits of a global approach to come up with this new technology.

HID as lightsource in the automotive world has been proven as the most efficient way to satisfy the main user's requirements on a headlighting bulb: Realize a broad beam pattern with superior performance on visibility, safety and comfort on the one hand, and the fulfillment of long lifetime requirements on the other hand. In the second step, the logical integration of functions and the improvement of automotive system requests such as size and EMC has to be covered. An integrated bulb with starter is the appropriate way to combine these features: Optimized fine tuning between the entire lightsource and the starter to reach optimal electrical and EMI performance on the one side on the other side combined with very compact sizes leads to an automotive source perfectly suiting to the modern trends in headlighting applications.

The recently developed technology of micro-discharge lamps allows to realize high-efficient metal halide lamps with low power consumption and high lighttechnical quality. Because of their compact construction and superior optical performance they are the base for optimized lighting systems for special lighting purposes in a number of applications. In a special study project Philips Lighting investigated the opportunities of automotive lighting with fiberoptic systems. Main aspect of the study was to adapt the light source for optimal system performance. The results showed that it is possible to realize different lighting applications as headlamps and dashboard lighting with one central light source. In an evaluation of different optical configurations the influence of the lightsource on the total system efficiency will be shown.