October 16, 2002

Head-up displays

Recently, I drove two very different vehicles, both equipped with Head-Up Display systems. The two cars? A Corvette, and a Buick LeSabre. Head-up displays are found on few passenger vehicles, and the ones that do have it all seem to be General Motors products. Perhaps this is because HUD systems have primarily been used on military aircraft, and GM's purchase of Hughes Electronics, a military electronics supplier several years ago, gave them a head start. I predict we will see these systems on everything from economy cars to Semi trucks in the future. Let's take a look at how they work and the advantages they offer.

The concept of Head-Up Displays is simple. Move the important information a driver needs to see up into their line of sight, so they don't have to take their eyes of the road. To do this, Head-Up Display (HUD) projects the image so it appears to float in mid air, just past the front end of the vehicle. Now the driver's eyes don't have to refocus to see gauges and indicators, and then refocus again to see the road ahead. Studies made at the University of Berkeley, California, have found the timing between looking at dash mounted instruments and looking back on the traffic is about two seconds, whereas a head-up display in this configuration takes only 0.5 seconds. In the time it takes your eyes to refocus at highway speed, your vehicle travels several car lengths further down the road. Wildlife, another vehicle, or a pedestrian could suddenly pop out in front of your vehicle, and keeping your eyes on the road allows us to react sooner. In situations like this, every fraction of a second counts.

The HUD system used on General Motors' cars is a separate electronic module added to the vehicle. It sits behind the instrument cluster and includes a microprocessor and projector. Information to be displayed is sent from other modules or switches on the vehicle to the microprocessor. The microprocessor then controls the projector to shine the information upward onto the windshield glass in front of the driver.

Although the information is only projected onto the windshield, to the driver it appears to be floating in mid air in front of the vehicle. Dash mounted switches signal the HUD to dim or brighten the display or to move it up or down to adjust for different driver positions.

Not all information is shown on the projected display. Usually vehicle speed, turn signal and high beam indicators, and sometimes audio selection are all that are displayed. Warning indicators will also light up if a vehicle problem develops. By keeping only commonly used and important information displayed, the driver's attention stays on the road.

BMW Williams has just introduced a prototype HUD for Formula 1 racing next year. Instead of projecting the information onto the windshield, the complete HUD system is small enough to be integrated into the driver's helmet. Five organisations worked together to develop the system. DesignworksUSA was responsible for the mechanical design. Kopin Corporation is known for their dime-size ultra-high-resolution, ultra-bright, and ultra-light active matrix liquid crystal displays. Schuberth is the helmet manufacturer, with about 80 years in the helmet business. BMW Williams F1 team set the requirements and did the testing, and the last was the BMW Technology Office.

BMW Technology uses the research and development of the Formula 1 HUD system to significantly reduce the amount of time it takes to make this type of technology feasible for the passenger vehicle market. It is unlikely we will have to wear a helmet, such as Ralf Schumacher does on race day, but the same advantages exist.

The BMW Williams HUD system uses an imaging module located in the peripheral vision area of the driver. Instead of the typical Formula 1 steering wheel display, the HUD is full colour, much larger (about a 6 inch diagonal display), and doesn't constantly move during turns. The image appears about arms length and can be programmed to warn the driver of dangers on the track, such as oil or debris, pit information, or vehicle information.

HUD is primarily a safety system, keeping the driver's attention on the road as much as possible. As the cost and size of components continues to shrink, perhaps soon we will all be able to take advantage of these systems.

Jim Kerr is a master automotive mechanic and teaches automotive technology. He has been writing automotive articles for fifteen years for newspapers and magazines in Canada and the United States, and is a member of the Automotive Journalist's Association of Canada (AJAC).

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