Some customers' specifications as well as international regulations for headlamps require a low value for stray light in a wide angular region so that is possible to avoid glaring conditions for drivers on other vehicles that came from the opposite direction and for the driver of the vehicle himself. This aspects became more important if we are considering headlamps that utilize as light source High Intensity Discharge lamps or that mount AFS systems. In fact, with a Xenon Bulb the higher luminous flux available in comparison to the Halogen Bulb, means that even stray light will be higher. In AFS system not only there is more light but the glare changes in function of different AFS configurations. Stray light is on one side strictly related to fundamental geometrical characteristics of the headlamps such us reflector, walls, bezel and lens geometries and, on the opposite side, due to optical characteristics in terms of reflectance of materials that build the headlamps and of adopted surface treatments (i.e. aluminizing or lacquering) or mould surface treatments (i.e. sand-blasting). It could happen, if stray light values have to be taken into account, that particular stylistic solutions should be preferred to others. These aspects must be clarified early with customers, usually a long time before having molded pieces to analyze in a laboratory. So it is necessary to be able to simulate these characteristics and to have a good data base of different bezel materials utilized in production as well as to individuate the best optical models to realize optical simulations for these parts. In this paper an experimental method for characterizing bezel materials and the application of these data in optical simulations are presented. The roughness data base for bezel materials could help in predicting headlamp performances from the beginning of the project when just optical simulations are available. This has been shown for particular headlamps with HID lamps.


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    Title :

    Importance of optical surfaces roughness characterisation to increase predictive value for headlamps optical simulations


    Additional title:

    Bedeutung der Charakterisierung der Rauigkeit optischer Oberflächen für die Erhöhung des prädiktiven Aussagewertes optischer Simulationen


    Contributors:


    Publication date :

    2003


    Size :

    14 Seiten, 14 Bilder, 3 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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