Vertical Designs for RID Solutions: Challenges for Legal Requirements and Consumer Ratings

For many years headlamp designs were guided by the size and shape of main light reflectors. With the change to modern projection module systems, this dynamic shifts more and more. Now main light are also subordinate to the general design of headlamps and cars. With this change, new challenges arise. Low width and height requirements of the projector lens a-surface lead to reduced efficiencies or reduced output per lens area. At the same time, increased focus on customer ratings increases performance requirement. Therefore, headlamp setups are built using multiple projector modules to generate one main light function. These modules must be aligned to each other — especially for lowbeam aiming. Headlamps with two modules with horizontal offset that contribute to a low beam function usually don't pose a big challenge, due to combinations of foreground and kink modules and generally larger tolerance windows in horizontal aiming. But the more modules are involved in the light function, contributing to gradient and kink generation, the more complicated design of the setup and aiming gets. And especially modules with vertical offset pose challenges, not just for consumer ratings, but even legal definitions, due to possibilities of generating multiple cut-offs and differences in measurement distances. To discuss these challenges, specific examples will be shown and explained how they are handled with vertically stacked modules. The impact of aligning cut-offs at different distances and decisions on legal definitions will be the main focus for best performance, with special focus on interaction between FMVSS legal requirements and IIHS rating evaluations.