Coming to a car window near you (Image: Image Source/Getty Images)

DRIVERS are already bombarded with advertising on billboards and vehicles. Now even car windows could become part of the advertisers’ canvas.

Wallen Mphepö of the Beijing Normal University in China has come up with a way to turn car windows into billboards that could be used to display dynamic adverts and public safety messages.

Mphepö has developed a polymer film that can be attached to a window to act as a kind of screen, picking up images projected from inside the vehicle and transmitting them to viewers outside through a series of microscopic mirror-like structures. Thin vertical strips of clear film in between these structures allow the driver to see through the window as normal, Mphepö says.


Advertisers could use GPS to tailor the ads to the area where the car happens to be, or the time of day. “There’s no point in displaying ads for a great breakfast place at a time when people are effectively looking to go to dinner,” Mphepö says.

He will present a prototype device that gives a 2D image at the Society for Information Display conference in Los Angeles later this month. He believes he can produce a 3D image without the need for glasses by using the mirrored strips to display alternating images on either side of each transparent strip, angled so as to be viewed by the left or right eye. Mphepö ultimately hopes to design 3D cinema screens using the same micro-mirror approach.

The idea is interesting but could divert drivers’ attention away from the road, says Paul Green at the University of Michigan’s Transportation Research Institute in Ann Arbor. Even though drivers are used to seeing adverts, “a dynamic display would cause you to look longer at these vehicles and that might be more of a problem,” he says.

He also worries that people will be unable to see into a vehicle with the display. This could hamper drivers communicating with gestures at road junctions, for example, which is why some states in the US have banned tinted car windows. But Mphepö’s display could enhance safety if used to display public information messages, such as changes in the speed limit or warnings of approaching hazards, Green says.

Mphepö adds that a 3D display might be the perfect way to get drivers to take in urgent alerts. “It is more realistic and brings the point home for drivers who might otherwise be speeding,” he says. Last year the authorities in Canada experimented with a 3D image on a road surface, showing a child chasing a ball, to see if it could make drivers slow down.