- Products & Services
 Frost & Sullivan
In bi-xenon headlamps, the low beam and high beam lights are generated with just one projection module, which is mechanically switched between low and high beams via a shutter in the headlamp. Since the light retains its color and intensity, the human eye perceives the illumination as unchanged. Compared to a halogen low beam, a xenon low beam is characterized by a brighter and more widely illuminated road. The range of the high beam is much greater, and the edges of the road are illuminated more clearly.
With xenon headlamps, the automatic or dynamic headlamp leveling systems always ensure correct beam settings depending on the load, the braking process and/or vehicle acceleration. The vehicle load status is measured by inductive or magnetoresistive axle sensors, and head-lamps are repositioned using servomotors. With dynamic headlamp leveling, the vehicle speed is processed via the speedometer signal. This means that the lamps can quickly compensate for braking and acceleration processes.
The complete xenon system also includes a power wash system that keeps the headlamp cover lens clean so that the xenon light is directed onto the road and drivers of oncoming vehicles do not have to contend with added glare.
Dynamic bend lighting was introduced in 2003 to provide drivers with an improved, larger visibility range. In this system, light modules rotate according to the steering angle. The next stage in development of advanced headlamp systems came in 2005, with the introduction of the Adaptive Frontlighting System (AFS). Based on the VarioX module, headlamp light distribution is adapted to the specific situation according to the vehicle’s speed and steering angle. Then, in 2009, a new breakthrough was achieved: For the first time ever, a headlamp system was combined with a camera as a sensor, allowing the combined unit to rely on data collected from the vehicle’s surroundings alongside data from the vehicle itself. When the adaptive cut-off line (aCOL) is generated in this way, the light cone of the vehicle’s headlamps is controlled so that it ends in front of the other vehicles. Today’s state-of-the-art glare-free high beam systems go one step further, automatically masking areas of the road where lighting could annoy other drivers.
Reasons for this development are the potentials which the LED has. As it delivers not only environmental benefits, it also enhances the driving comfort with its light colour similar to daylight. Furthermore, the light source also offers a great deal of styling potential, and can help manufacturers create a distinctive image for their brands.
Responsible for the light generation in a LED is a semiconductor crystal that emits light when it is electrically stimulated. As in the conventional light sources, the light distribution can also be generated by using reflection or projection systems. The challenge for both systems includes achieving a good thermal management. The LED chip has to be highly effective in dissipating the power lost by the LEDs and discharging it to the system’s surroundings.
Meanwhile, LED headlamps are not only available for premium vehicles. They increasingly enter mid-size models as well. Whereas, the main lighting functions low beam and high beam are realized with LED in the mid-size models, in the upper class models adaptive systems are increasingly come up. Thus far, LED based systems are available with AFS functionality as well as camera based functions, like the glare-free high beam.
One advanced development based on dynamic bend lighting is the Adaptive Frontlight System (AFS). This system uses both the steering angle and the vehicle speed as parameters for illuminating the road. Based on this internal information, a cylinder in the VarioX module is used to create various types of light distribution, including town light, country light, adverse weather and motorway light.
The development of the adaptive cut-off line (aCOL) goes one step further. This feature also utilizes data gathered from the vehicle’s surroundings to generate the light distribution. A camera detects oncoming traffic and cars ahead, and a stepper motor turns the cylinder of the VarioX module to the required position within milliseconds. This means that the light cone always ends directly in front of oncoming traffic, or just behind the car ahead of you.
The glare-free high beam function means that drivers can drive with the high beam on at all times. If the camera detects other traffic on the road, the distribution of light from the high beams is adjusted to mask the specific area.
Now used to illuminate broader areas than ever before, LEDs will also perform the opposite function in the future. Targeted spotlighting functions will allow specific illumination of certain types of objects, such as children playing at the edge of the road. This draws the driver’s attention to these potential risks ahead of time, enabling faster responses.
The first step in this direction is the adaptive cut-off line (aCOL):
A camera on the front windshield detects oncoming vehicles and vehicles traveling ahead, and the system adjusts the headlamps so that the light cone ends before it reaches the other vehicles. This allows the range of the low beam lights to be increased from about 65 to up to 200 meters (3-lux line). If there is no traffic ahead, the system switches to high beam, giving the driver optimum visibility at all times. The system also uses vertical angle information to make deductions about road topography, improving illumination in hilly terrain. The possible range of the headlamps is based on a feature that checks the level of glare from other road users. This helps prevent annoying glare and provides maximum low beam light distribution.
Glare-free high beams permit drivers to keep their high beams on at all times, but minimize glare that might annoy other drivers.
This type of system features a front camera, high-performance software and intelligent lighting technology, and automatically masks high beam distribution to areas of the road where it might annoy other drivers. This significantly increases high beam use at night.
If the camera detects road users who are at risk of glare, the area around the road user detected by the camera is automatically masked. This masked sector can even follow that road user dynamically. The area directly in front of the vehicle is illuminated at all times with a standard light distribution pattern comparable to today’s low beam light levels. The brightness of the variable zone above the cut-off line can be adjusted locally. One possible way to provide glare-free high beam functionality is by installing a special sheath on the rotating cylinder in the VarioX® projection module. Based on image processing functions and intelligent settings in the VarioX module, critical areas of oncoming traffic that might face glare are simply removed from the high beam distribution, but the rest of the high beam field remains intact for the driver’s convenience, yielding a considerably greater range of visibility as compared with standard systems.
Such a function is technically possible thanks to the splitting up of the high beam into five reflectors, each one having a chip containing 5 LEDs. For the first time ever, the lighting expert, HELLA, has now succeeded in operating every LED on the 5-segment chip separately, whereby a total of 25 LEDs per headlight can be operated on full power or lowered as and when required.