New design tools for LED headlamps

The automotive lighting technology is in considerable progress due to new components, e.g., High-Power-LEDs and light guides, and new sophisticated production techniques. Furthermore, great importance is being attached to the appearance of front and tail lamps. White High-Power-LEDs have reached a development stage that affords its reasonable application to low beam headlamps. This challenging illumination function requires sophisticated design techniques in order to preserve the advantages associated with this source type. Thus, high efficiency and stylish appearance have to be reconciled, e.g., with the use of freeform surfaces. Beside the demands from manufacturers and customers, car lamps have to meet several regulations (ECE, SAE, etc.). This contribution describes the illumination design of a LED-based low beam headlamp using advanced mathematical methods, e.g., 3D-Tailoring, automatic optimization, and Virtually Reflecting/Refracting Surfaces (VRS). We propose this new surface type with non conventional reflection/refraction properties as an advantageous design tool for the first layout and for automatic optimization, as well. For efficiency reasons, special attention will be paid to the creation of the cut-off line without using additional stops.