Car with welcome light
You’ve just enjoyed dinner and now it’s dark outside. Unfortunately, the restaurant parking lot is rather poorly lit, but the driver knows what to do. With just a press of the key fob, a striped carpet of light appears on the ground illuminating the path to the car.
This design element available on the new BMW 7-series is based on special microoptics developed by the Fraunhofer IOF in Jena. Thanks to these specially designed microoptics it’s possible to project light beams from the underbody to the ground in a striped pattern covering around four square meters at the vehicle doors on both sides.
These guide lights are not a completely new feature, and other premium carmakers are also working on similar systems for their vehicles. To date, though, these lighting systems have been installed in either the exterior mirror or the door. This is problematic: When integrated into the mirrors, the light moves away from the path it is supposed to illuminate when the door is opened; placed at the bottom of the door, the light cannot reach the ground below until the door is opened.
The BMW Welcome Light Carpet is different.
With this system, the lighting module is installed on the body sill to the vehicle underbody under the driver’s door. The microoptics feature microlenses that aim the light directly at the desired surface. Initially, the IOF scientists’ goal was to create tiny yet powerful digital projectors such as those used in smartphones.
The researchers make the projectors extremely small, but they put many of them together in a honeycomb array. They can alter the intensity of the light by altering the number of microprojectors used. Regardless of whether 150 projectors are used, as with the BMW Welcome Light Carpet, or 3,000 of them, the thickness of the array still remains within a range that is measurable in millimeters.
Projection lenses can be arranged individually.
One positive side effect of this type of array lighting proved quite significant during the development of the Welcome Light Carpet. The projection lenses that catch the light and reflect it onto another surface can be individually positioned relative to the light source. As a result, the images reflected by the individual lenses in different locations can be made to precisely overlap one another.
This means a high-quality and high-intensity image can be projected even if the angles of illumination are extremely low. In its first consumer application as the BMW Welcome Light Carpet, this technology gives the BMW 7 Series a new nighttime look.
The BMW Welcome Light Carpet is now standard equipment on the new BMW 7 Series. There is an extremely wide range of possible uses for this type of array lighting, extending from safety technologies and medical applications to mechanical engineering and traditional signal lighting.