DETROIT - Not all technology is grand. Who doesn't hate the bluish-tinged, high intensity discharge (HID) headlights that have appeared on some higher-end models in North America? You know the ones that zing your eyeballs with way too much glare whether they're reflected in your mirror or if they're coming at you in traffic.
GM's luxury division, Cadillac has signed on with the German automotive supplier Hella KGaA Hueck & Co., to offer a solution - low glare Light Emitting Diode (LED) headlamps. Used previously only on concept vehicles or exotic sports cars, LED headlamps, for low- and high-beam headlamps, will be offered on its Escalade Platinum edition SUV.
"There was never a glare issue (even when the high beam lights were on)," said the designer of the Escalade Platinum's LED headlamps, Siggi Hetz of Hella. He explained that there isn't as much glare as a high-intensity discharge light or traditional halogen high beams because the light will be distributed across five lenses (or seven lenses when the high-beams are used) on the Cadillac SUV.
"The luminous flux, or energy density, is relatively low, that's why the eye doesn't perceive as that much volume or glaring," Henz said. "We performed tests with Cadillac on the Escalades with this lamp and the halogen. The funny thing is that the halogen lamp, which has the lowest amount of luminous flux, is actually the one that glares the most. That's because the energy density is so high."
When a person is standing up to 20 or 30 feet away from the SUV in a dimly lit room, the LED headlights do not seem to have the same glare as a halogen bulb - either in low-beam or high-beam mode.
If someone crouches down, near the ground - not a typical position for a driver behind the SUV or in front unless the vehicle is cresting a hill, the five LED lenses do appear very bright, but the glare was no worse than that of an ordinary headlamp.
"The LED headlamp will further enhance the visibility and further enhance how driver perceiving the road in front of him," added Martin Fischer, president of Hella Electronics Corp., which is part of Hella's North American operations is based in Plymouth, Mich.
On the Escalade Platinum the standard one bulb arrangement was replaced by a module of multiple LEDs. For normal low beam usage, five LEDs, using five different lenses to disperse light in front of the vehicle, were arranged in a vertical column. Adjacent to the column of five lenses were two circular lenses for the high beams plus a vertical white light bar and a yellow, turn signal light bar. Again, all the lighting was from LEDs, not traditional bulbs.
This new headlight array will allow Cadillac to achieve a distinctive vertical styling cue for the Escalade while providing white light, similar to sunlight, Fischer said. Traditional halogen bulbs, on the other hand, provide a warm, yellow color, but 89 percent energy is transmitted as infrared light and rain and fog severely degrade their usefulness.
Displayed in a dimly lit conference room in the MGM Grand casino, there were no opportunities to see how the vehicle would actually behave at night, but Product Manager David Schiavone of General Motors related his experiences.
"I have personally driven (the Escalade Platinum edition prototype)," Schiavone said. "My experience, the thing that pops up more than anything, the light is so white and so much like daylight is that the signs just pop. They almost glow, like the speed limit signs. You can see them before you come up to them.
"The other thing, because it is white light and more like daylight, there is less eye strain. I think people who are doing more night driving are going to find that they are not going to have nearly the same amount of eyestrain. So, those two things are what I've experienced in my limited 30 to 60 minute drives."
From a distance, the lights from an oncoming Escalade Platinum look normal - one source of light, Schiavone noted. Then, as the SUV gets closer, the light source becomes vertical.
At night, motorists can always distinguish a Cadillac on the road - from behind - because of the brand's signature vertical taillights. From the front, a Caddy's headlamps look pretty much like any other vehicle. This will change with the new headlamp configuration.
LEDs were invented in the 1920s, but didn't begin to enter the marketplace on devices in earnest until the 1960s. For the past 15 years, LEDs have been used in vehicles for a light source. Hella KGaA Hueck & Co., for example, began producing a LED headlamp for the Audi A8 W12 in 2003.
Other vehicles have used LED headlamps, but Cadillac and Hella executives stress that the Escalade is the first to use "fully functional" LEDs for low beam, high beam, daytime running lamp, parking, and turn signal functions.
The Escalade Platinum's LED headlamps also can operate in a depowered fashion to be used as daytime running lamps, plus the module uses parking lamps and vertical light bars that are powered by lower intensity LEDs.
"The Cadillac Escalade Platinum will be the first high-volume vehicle in the world to be equipped with full LED headlamps," added Steve Widdett, Hella executive vice president, Automotive Sales. "This marks a significant milestone in advanced automotive lighting."
Hella's Fischer acknowledged that because of the cost of this milestone only a limited number of customers who desire to have high technology would purchase LED headlamps, but getting the Cadillac Escalade Platinum business "is a big step" but "limited step" in showcasing how well it works.
For possible future products, Fischer said that Hella is testing glare-free high beam headlamps and something called a "marker light." Special LEDs could be used to light objects to the sides of the vehicle when they are detected by future external vehicle sensors.
The objects, whether animals, people, or construction barrels, would be illuminated by the marker lights until the vehicle passes them.
Hella expects LED headlamps usage to grow in North America, but halogen and HID headlights will retain their market share for many years.
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