Innovative technologies

Flexible screen technologies

The original challenges for car windscreens were clear vision and protection against the weather . Today, they do much more than that. For example, Anti-Theft Glass has been developed to protect against crime. And the Head-Up Display provides the option of projecting important information as a virtual image in front of the windscreen and thus in the field of vision of the driver. Technologies which not only improve driver comfort, but also driver safety.

Every car driver is confronted with a wide variety of stimuli which can distract his attention from the traffic while he is driving: whether he is switching radio station, chatting with the passenger or just looking at the dashboard. For example, the average driver needs one second to check his speed, at 30 mph he is covering 50 ft in this second.

So the automotive industry is constantly working on minimising this distraction by designing the controls of the vehicle accordingly. The Head-Up Display (HUD) is a promising development. This involves projecting information onto the windscreen, direct in the driver’s field of vision, so he doesn’t need to move his head down or avert his eyes from the road. Initially, BMW fitted the HUD into prototype vehicles and a variant was tested in Formula1, where a miniature display was integrated into the helmet so the image could be projected against the visor. However, the roots of this technology are in aviation. In aircraft, Head-Up Displays of these kinds have been helping fighter pilots for decades and were used in display technology in civil aviation for a good 15 years now.

When it came to the development of an application for production use in cars, BMW cooperated with the automotive supplier Siemens VDO and the technology is already available as a special option for the 5 and 6 Series. The HUD works on the following principle: The vehicle’s dashboard includes a projection unit consisting of a TFT screen, a light source and several mirrors. Light is passed through the screen, deflected by the mirror and projected against the windscreen. At a size of around 18 x 9 cm, the virtual image is optically perceived at the optimum ergonomic distance, hovering at about 2 m above the bonnet. So the driver neither has to divert his eyes from the road to get important information nor adjust his eyes when switching between close and distant objects and vice versa. Compared to conventional display systems, the HUD reduces the time take to absorb the information by nearly a half: “We can display various values and information, such as the speed,” Gunnar Franz from the BMW Group describes the display. “Depending on the configuration, it is also possible to display navigation instructions or other vehicle information, such as active cruise control or check control warning messages. It makes no difference what the weather conditions are. Whether you’re driving through rain, fog, darkness or direct sunshine, a light-sensitive sensor adjusts the brightness of the image to the environment. This automatic brightness adjustment by the HUD means it is no longer necessary for the eyes to adjust to the difference in brightness between the road and the interior of the vehicle. And this by no means exhausts the potential of the Head-Up Display.