HolographIC tail light
Holography – when this word is used, many people perhaps immediately think of "Star Wars" and Princess Lea. Little R2-D2 beamed her as a hologram into an intergalactic meeting of the Jedi Knights. Science fiction, for sure. But holography itself is by no means fiction. On the contrary. In the not too distant future, the use of holograms in the tail lights of automobiles is conceivable. A so-called volume hologram is used for this. The hologram is visible from different angles, so that a three-dimensional impression is created. Soon it could provide a completely new design and functional spectrum of tail lights. Volkswagen is therefore now presenting the first prototype of this new generation of lighting functions: the holographic tail light.
Holograms in the tail light cluster become visible using LEDs
This is how the hologram is made: an object is irradiated with a laser and then stored on an exposed photopolymer – a transparent holographic film as the carrier of the hologram. Before the object is irradiated, the laser beam is split into a reference beam and an object beam. Both parts of the laser beam reflect onto the photo plate and expose it. Here the hologram is "written" into the photopolymer. If the transparent photo plate is now illuminated with the angle of the reference beam, the three-dimensional object is created virtually. Depending on the viewing angle and light source, the viewer can even walk around the object and view it from different perspectives. With the holographic tail light cluster, LEDs illuminate the photo plate exactly at the angle of the reference beam. As a result, a virtual three-dimensional light function appears in the tail light cluster. When switched off, the area of the light function is almost transparent. Only when it is illuminated as shown does the lighting function emerge in front of, above or behind the tail light cluster.
Light is created where there is no physical space available
The holographic tail light offers a wide range of new possibilities. You can create light where there is no physical space. You can create new lighting effects. Light can be optically extracted from the tail light to create a plastic effect. It is possible to make the representation or visibility of the lighting function dependent on the viewing angle. The light sources themselves are "hidden" – no longer visible. Classic lighting functions such as the turn signal can also be displayed. A turn signal with a different colour could be placed behind a tail light hologram, which also seems to float freely in the tail light. In addition to the classic lighting functions, graphics such as the GTI logo could also be integrated in a free-floating manner to ensure that the statutory lighting functions are not impaired. For example, the GTI logo would only be visible to the observer standing next to the car.