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Headlamp performance is typically discussed as a characteristic of the individual headlamp. Parameters like homogeneity, light volume, range and spread of the light pattern are measured and evaluated. However, to assess the headlamp performance relevant for the driving situation, the complete headlamp system as it is mounted, aimed and driven in the car must be the subject of the evaluation. The foundations for the headlamp performance are laid out during the development process of the headlamp. Here the characteristics important for the performance have to be weighed against other aspects, mainly styling and costs. In this paper the system components and other parameter are discussed regarding their impact on the performance of the headlamp.

One of the most important features of a headlamp with adaptive light distribution is the improved side illumination for driving situations in towns, at intersections and in small radius curves. Pending legal requirements will allow use of bending light realized by side illumination from either a part of the low beam or a separate cornering lamp. The first part of this paper compares the legal requirements of both SAE and ECE regulations for bend lighting and cornering lamps. The second part discusses the performance of different lamps developed on the basis of these regulations. They are compared with respect to technical and performance aspects.

The percentage of cars using a projection type headlamp is growing quickly. Lens diameters of 40mm, 60mm, and 70mm are being used in combination with halogen bulbs and gas discharge lamps. The signal image of such projection systems can be improved by increasing the light emitting area with additional optics around the lens. This results in a more comfortable appearance of the headlamps from the viewpoint of oncoming cars. Different optical elements, e.g. Fresnel lenses, prisms, segmented reflectors, are used. A large set of existing projection systems with additional optics around the projection lens is examined and rated by test persons regarding glare, size of the signal image and homogeneity. Also luminance measurements are presented. The correlation between these results are discussed and recommendations for the deign of signal enhancements are given.

For headlamps whose low beam function is equipped with High Intensity Discharge (HID) technology, a high beam counterpart of equal lighting performance is presented which fits in the constructional space available in modern cars. The new Bifunction HID system allows the use of HID technology for both low and high beam in the same reflector, utilizing the same bulb and electronic control unit. Bifunction HID technology on the basis of reflection as well as projection type systems will be presented in this paper. An overview of the regulation guidelines for world wide application of this new technology is given. The main aspects of the switching mechanisms and their effects on the light distributions are discussed and compared.

For the automotive industry, the styling of a car is an important feature. Since the appearance of a car is strongly characterized by the headlamp, stylistic aspects have an increasing influence on the development of headlamps. At the same time, the trend goes toward reducing the constructional volume available to the headlamp and also integrating other functions such as foglamps. To fulfill all these requirements, new reflector shapes had to be created. In this paper, different reflector concepts for low beam, high beam and foglamps are presented. They will be discussed under consideration of stylistic aspects (e.g. space for the required bulb shield, semi-clear outer lens) and technical aspects (e.g. thermal stress of plastic lenses).