Bright ideas: let there be light

You can never be too rich, too thin, or have too much light.

That's an apt philosophy of automotive lighting-system producers who, after years of offering incremental, evolutionary changes to conventional incandescent bulb technologies, now are flooding the marketplace with myriad new lighting concepts. Headlights, taillights and interior lighting systems all are being attacked with a variety of new systems that produce more and higher quality light. Among them: * High-intensity discharge (HID) headlamps. They produce three times as much light as conventional halogen lamps using only two-thirds the power, and provide nearly twice the spread of light on the roadway. HID headlamps also last two or three times longer than typical halogen lights because there's no filament to bum out. Despite their greater light output, the beams also are more controlled and focused, so they pose no hazard to oncoming drivers. However, Japan, Europe and the U.S. differ on what the ideal beam pattern is and have different requirements, so headlight beams must be customized for each region. Lighting specifications are gradually becoming more standardized worldwide, but still have a long way to go.

* Neon taillights. Because they light up faster than conventional taillights, proponents say they give vehicles traveling behind more stopping distance and an added margin of safety.

Neon also provides styling benefits and longer life advantages. LEDS (light emitting diode) also are being used in these applications for the same reasons and promise a technology horse race with neon.

* "Subminiature" fluorescent lights. Slim and long-lasting, they are touted as being ideal for interior applications where space is limited, such as behind-the-dash instrument panel lighting.

* Distributed or centralized lighting. These systems use fiber-optic cables to illuminate numerous areas of the vehicle from one central light source. Benefits include major packaging improvements, weight and power savings, improved serviceability and better light consistency; they can replace dozens of individual lights and bulky copper wires with thin fiber optics.

* Variable light-pattern headlights. An experimental concept from Robert Bosch Corp., the headlights are composed of eight smaller lights connected to sensors that monitor steering and driving conditions and adjust beam patterns to optimize driver vision.

Automakers such as General Motors Corp. and Volvo AG also are equipping their vehicles with daytime running lights (DRLs) in the U.S. -- headlights that essentially stay on whenever the car is running -- although at reduced power -- to improve visibility and safety. DRL's are required in some countries, but are gaining popularity even where they're not.

Why the sudden gush of new technology? Suppliers offer a variety of reasons -- from aging U.S. drivers to over-stressed electrical systems -- but the primary impetus seems to be related to styling, marketing and safety issues.

"Our emphasis now is to reduce size, make them better and more efficient and reduce cost. In order to do all this you can't keep using the same bulbs and materials that you've used in the past; you have to move to something different," says David Moore, engineering manager-forward lighting at General Motors Corp.'s Delphi Interior Lighting Systems Div.

And unlike many new vehicle features such as air bags and antilock brakes, the benefits and value of improved lighting can be enjoyed on a daily -- or nightly -- basis.

For instance, Fritz Wilke, director of automotive sales at Robert Bosch Corp., says HID headlamps are a popular option on the BMW 75Oil even though they cost about $1,000 extra in the U. S. The increase in night vision is so dramatic that many 750 owners without the special headlamps are asking dealers to retrofit their vehicles. "There definitely is a public demand for better visibility and improved illumination," he says.

If buyers of a $90,000 car are willing to pay $1,000 for HID headlamps, then those shelling out $20,000 or $30,000 should be willing to spend at least a few extra bucks for the technology, most proponents argue. As volume picks up, they expect prices to drop dramatically.

HID systems produce light by exciting an inert gas with electrical energy instead of using a conventional filament, which is delicate and very susceptible to shock and vibration. As electricity jumps between two electrodes the gas -- instead of a filament -- glows.

The design is very efficient, durable and compact, but it requires a complex electronic system to make it work and that's where cost comes in. Even so, suppliers are confident the cost of this electronic "ballast" will drop.

"If you look at every electronic device that comes along, it starts out at some price level and then comes down," says Delphi's Mr. Moore. Electronic calculators once cost $200 to $300, and they now cost $4 or $5, he points out.

Even so, no one is predicting that HID headlamps will catch on overnight. Instead, a relatively slow phase-in is expected, moving gradually from high-line luxury vehicles to less-expensive, higher-volume vehicles. Tom Stanton, manager of global automotive new products at the GE Lighting unit of General Electric Corp., says it may be 15 years before HID dominates automotive front-end lighting.

Besides the BMW application, HID systems currently are used on a Porsche AG turbo model and the Audi A8. At least four more platforms are expected to use HID systems in the 1996 model year.

Ford Motor Co. is the first U.S. automaker to offer the feature -- on a limited-production 1995 model Lincoln Mark VIII.

Ford touts HID's brightness, efficiency and durability, and also emphasizes that the system's bluish light "contains traces of ultraviolet, which accentuate fluorescent material in road markers, adding a further element of safety to the driver."

"This system has it all -- style and substance," says Jeff Erion, project manager-Ford Lighting Technology Group. "Not only does it provide more light on the road, exactly where the driver needs it, but it also offers designers new freedom to shrink and shape lamps for unique designs."

Flexibility is a key selling point for HID. Thanks to the intrinsic efficiency of HID systems, they can be packaged much smaller than conventional halogen lights yet still produce the same amount of light. That gives designers much broader latitude to shape lower, more sloping hood lines.

Ford also is the first automaker to use neon rear lights on a production vehicle. It replaced halogen with neon on the rear high-mount stoplamp of the '95 Explorer sport utility. Ford cites safety as the main reason for the switch. The neon light flashes on in three milliseconds compared with milliseconds in a typical halogen light. That means drivers travelling behind the vehicle will get an earlier warning and gain as much as 19 extra feet of stopping distance at 60 miles per hour, Ford says.

Neon lighting offers other consumer benefits, including energy efficiency and longevity. It cuts energy usage by 40% compared with halogen and lasts about three times longer. Like HID systems, neon systems last longer because they operate without a filament, explains J. Thomas Smith, director of engineering for Osram Sylvania Inc. Conventional taillight filaments are affected by shocks and vibration such as trunk slams and often fail prematurely because of this. Most suppliers say neon lights should improve warranty costs in this area.

The quality benefits of neon include a more uniform distribution of light across the lens face because of the physical shape of the light source. Neon tubes also can be bent into a variety of shapes to conform to the body contour of a vehicle. "This will permit the automobile stylist or designer more freedom," says Mr. Smith.

However, neon systems are meeting with intense competition from producers of LED systems such as Hewlett-Packard Co. that offer many of the same benefits and already have established a presence with applications such as the high-mounted stoplight/strip on the Cadillac Seville. There is a good deal of debate over which system is most cost-effective.

Another lighting innovation, this for interior applications, are so-called "Subminiature" fluorescent lights. Ford adopted this system on the 1995 Lincoln Continental, Supplied by Osram Sylvania, it provides an even, white backlight similar to that seen on a high-line Lexus model, but Osram's Mr. Smith says its benefits go far beyond mere aesthetics. Subminiature fluorescent lighting offers up to 10 times the life of incandescent bulbs, and also provides a more even distribution of light, eliminating hot spots. Fluorescent tubing also provides many packaging and styling benefits as well, he maintains.

Distributed or centralized lighting systems are much further off on the horizon. Suppliers say it's unlikely they will be seen during this decade, yet every major lighting supplier has demonstrated prototype systems and is eagerly refining the concept.

GE Lighting's Mr. Stanton says the Society of Automotive Engineers has created a task force to study and recommend standards for distributed lighting, including the use of backup systems in case the main light source fails. Although many hurdles remain, he says the space- and energy-saving benefits are compelling. The same apparently is true of Bosch's variable-light-pattern experimental development. Bosch's Mr. Wilke says intelligent light systems so far have been well received, but working with the SAE and various government agencies to determine appropriate lighting patterns remains among the many challenges he faces.

When it comes to U.S. government regulations, it seems, even lighting engineers are afraid of being left in the dark.