Variable light functions
Here you will find useful information and handy tips relating to AFS headlamps, which stands for Advanced Front Lighting System.
Important safety note
The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for use by suitably qualified personnel only.
The automotive lighting technology industry has been working to ensure optimal illumination of traffic areas for many years. On the one hand, the road and its surroundings should be illuminated as brightly as possible, so that the driver can safely recognise objects in the traffic area. On the other hand, other road users and the driver themselves should not be dazzled. As such, one of the focal areas for HELLA's lighting technology specialists is to figure out the best way to reconcile, or even eliminate, the conflicting objectives of ensuring excellent illumination while eliminating glare for both the driver and other road users.
The classic solution is switching between high beam and low beam. While the high beam provides a light distribution optimised for illuminating the road, the low beam is a kind of compromise solution to avoid glare. Therefore, the combination high beam/low beam does not represent the optimal state-of-the-art solution when it comes to safety during nighttime driving. A simple, obvious improvement in adverse weather conditions would be to equip the vehicle with special auxiliary headlamps, such as fog lamps, which can be turned on or off by the driver according to the situation. The next step would be to not implement these additional lighting functions as individual auxiliary headlamps, but to integrate them into the main headlamps and to make the switch between various light distributions automatic. This is the basic concept of AFS headlamp systems (Advanced Front Lighting System).
The low beam is merely a compromise solution between all partial light distribution options. Therefore, the Advanced Front Lighting System was developed as a dynamic lighting system that allows for the best possible illumination of the road according to speed and steering angle. To implement it, a VarioX® projection module with a rotating cylinder between light source and lens is required. The cylinder is characterised by the fact that it has varying contours and can also rotate around its own longitudinal axis. A stepper motor turns the cylinder to the required position within milliseconds.
* The listed speeds may differ according to the manufacturer.
AFS headlamp systems make it possible to achieve discrete predefined light distributions. The adaptation of the light distribution is dependent on the vehicle speed, the road type, and weather conditions, which represents an enormous improvement over conventional vehicle lighting technology.
As such, HELLA's engineers all agree on one thing: The ideal way to implement such a situation-dependent automatic headlamp system is to use the VarioX® module. This allows a single xenon light source to generate up to five different light distributions: Besides conventional low beam and high beam, this allows for town, highway, and adverse weather lights with the same headlamp module.