It’s 8 p.m. on a late winter evening, and we’re in southern France, sitting in a BMW sedan parked on a rural road. Its LED headlights illuminate the pavement up ahead as well as the tree trunks alongside it. It’s bright, much more so than halogen could achieve, and crisper than even Xenons.
As the driver puts the car in gear and we begin moving forward, the LEDs are augmented by BMW’s new Laser Light high beams, taking nighttime illumination into another dimension. It’s as if we’ve driven into daylight. Not only is the road ahead visible for an astonishing 600 meters (1,968 feet), around twice as far as the LEDs can illuminate, the amount of information being provided is staggering. We see not just the pavement and the tree trunks but the branches overhead, and enough of the surrounding area that we can tell not just where we’re going but where we are. What’s more, the light itself is the same color as daylight, making it feel natural and easy on the eyes.
The only time it’s a problem is when we come upon a reflective road sign; in France, they use black letters against a reflective white background, and the lasers put out so much light that the background is all we see. As the lasers constitute high beams, it’s easy to switch them off momentarily, and BMW’s engineers say they’re working on a solution. Most probably, they’ll end up dialing down the output, which they’ll have to do anyway to meet U.S. lighting requirements. Lasers will arrive in this country in late 2014 as standard equipment on the i8, and Federal standards limit output to 120 lux while the EU permits as much as 344. (Lux is a measure of light that takes into account the area of light as well as the amount, measured by itself in lumens.) Even dimmed down a bit, lasers will outperform LEDs by a significant margin, providing not just more but better light, and using about 30% less power to do so.
Along with the problem of too much light on reflective surfaces, BMW’s lighting engineers also had to address the effect of laser lights on those outside the car, specifically oncoming traffic and vehicles up ahead. BMW had already developed an auto-dimming function for its LED and Xenon high beams, and that technology is used here, as well. Laser high beams, however, can be left on while following another car in the same direction, because the system redirects the beams to either side of that car rather than straight ahead into its mirrors.
Other safety features ensure that the laser light itself never leaves the box, so to speak. Lasers can be used like scalpels when aimed directly at an object, so BMW sends the beam through a phosphorous plate that converts the blue laser into light in the proper spectrum while secondary optics redirect it down the road. In case of an accident, the laser remains safely contained within the headlight, and it should turn itself off before it can burn or blind anyone.
Intelligent lightweight design: Carbon fiber everywhere!
Laser lights may have been the most dazzling technology on display at BMW’s Innovation Day 2014, but they weren’t the only one, nor were they the only new technology to trickle down from the i cars.