Developed by companies such as Hughes Electronics (El Segundo, CA) for use in military jets, head-up displays (HUDs) are making their way in various forms to the automotive world. General Motors (Detroit, MI)—which now owns Hughes Electronics—has introduced a simple windshield-located HUD as an option in some of its luxury cars; the device projects information such as vehicle speed at a point perceived to be beyond the windshield. The fact that the information resides at a fixed point in space matters little to the average driver, who in the span of a moment might peruse a radio dial, a roadside sign, and a fellow passenger's smile while reaching for a coffee cup. In the world of automobile racing, however, the less often a driver must turn away from vital data, the better.
Engineers at Kopin's Visual Products Group (Scotts Valley, CA), BMW's Technology Office (Palo Alto, CA), and Schuberth Helmet (Brunswick, Germany) have developed a helmet-mounted HUD specifically for racecar drivers. The device contains a quarter-VGA (320 × 240-pixel) active-matrix display backlit by light-emitting diodes and is contained within the helmet's chin bar (left). It feeds images at video rates to the driver's right eye via a so-called free-form prism that makes up the entire optical system—a narrow-angled prism that directs the image via total internal reflection. "We earlier had more complicated optics," says Mike Prefz, Kopin's vice-resident of microdisplay business. "But we went to the prism for safety. It is a monolithic injection-molded plastic optical system that won't separate in a crash." The system sits just below the driver's line of sight and has exit pupil larger in the horizontal than the vertical direction, helping to accommodate the normal variation in eye-to-eye spacings.
Readable in bright sunlight, the HUD will convey a range of data to the driver. Track and vehicle safety information such as the oil spill indicated in a driver's-eye view (right) will be of paramount importance. Strategic data—for example, the car's position relative to other cars on the track—will be another area of great opportunity. The increasingly close communication between driver and pit crew could result in the development of entirely new racing tactics.