Laser headlight technology: Audi and BMW push the envelope

  • Audi racers at Le Mans
  • 1. Laser diodes create three separate beams of blue laser light. 2. The beams are directed through a prism, merging into a single beam. 3. The concentrated beam passes through a phosphorous lens that yields a diffuse white light, which is safer for human eyes. 4. The white beam bounces off a reflector and past a clear lens onto the road.
Date:23 July 2014 Tags:, , , , ,

Two premium-car manufacturers, Audi and BMW, are up and running with laser headlight technology. It offers several advantages, they say. Not everyone is in step with them, though. The USA, for one: this huge potential market is hamstrung by archaic light legislation that effectively prohibits these new-wave lights.

Never mind that BMW’s i8 hybrid supercar uses them. Or that Audi has used them to good effect as it once again dominated this year’s Le Mans 24-hour podium with cars using laser lights. Audi’s updated R8 supercar features laser lights, too.

Audi: race proven
Audi says it optimised its e-tron quattro hybrid drive and ultra technology for this year’s 82nd Le Mans 24-hour so the cars could run as fast as before – using as much as 30 per cent less energy. The tech certainly didn’t hurt the cars’ performance: Audi finished first and second, the brand’s 13th win in 16 starts.

The R18 e-tron Quattro racer combines matrix LED and laser light. “Audi is the trendsetter in lighting technology,” says Professor Dr Ulrich Hackenberg, Member of the Board of Management for Technical Development of AUDI AG. The latest version of the company’s flagship A8 sedan uses matrix LED headlights and these are going to be offered in other models, he says. But Audi has gone further by being the first manufacturer to introduce laser light in production cars.

Lighting up the track. At the International CES 2014 in Las Vegas in January, Audi showcased the Audi Sport quattro laserlight concept car and a front section of the new Audi R18 e-tron quattro including the headlights.

Integrating the eight-unit matrix LED headlights of the Audi R18 e-tron quattro with laser light provided a more homogenous and precise spread in front of the car, says Chris Reinke. “For us, this technology marks a milestone – it’s a reflection of the pioneering spirit of Audi Sport that, yet again, we’re assuming a pioneering role and, together with our colleagues in production development, deploying this new technology at such an early stage in racing.” Integrating the lights from the outset has made it possible to further optimise the car’s “smart” cornering light. Depending on the position of the car on the race track, it illuminates a corner even before the driver turns in.

According to Audi, after having tested the set-up, two-time Le Mans winner and former World Endurance Champion Marcel Fässler declared: “I’ve never had such good light on a race car as on the new R18.

“It’s clearly even better than last year. I wouldn’t call this just one step forward, but three. The laser light is brighter, more concentrated and more precise. For example, you can see the apex of a corner much better with it. At night, this could be a crucial advantage for us.”

Into production. The limited-edition Audi R8 LMX is the world’s first production car with laser high beams. When it goes on sale later this year, the R8 LMX is expected to cost the equivalent of about R3 million in Germany. Only 99 will be built.

The R8 LMX’s 419 kW V10 engine slingshots it from 0 to 100 km/h in 3,4 seconds. Top speed is 320 km/h. With that kind of performance, lighting will play an important role.

How it works. One laser module (each comprising four high-power laser diodes) per headlight generates a cone of light with twice the range of the all-LED headlight. The lasers have a diameter of just 300 millionths of a metre and generate a blue laser beam with a wavelength of 450 nanometres. As that blue light isn’t exactly ideal for road use, it has to be converted to white light. That’s done by a phosphor converter, which creates eye-friendly light with a colour temperature of 5 500 Kelvin.

The laser spotlight supplements the LED’s high beam. It operates at speeds of 60 km/h and above. An intelligent camera-based sensor system detects other road users and actively adjusts the light pattern to exclude them.

BMW: not in the USA
Our US colleagues are incandescent about laser lighting, if you’ll pardon the mixed metaphor. They’re urging their readers to rush to their computer and e-mail their local congressman right now. Here is what Basem Wasef had to say.

“Thanks to archaic headlight-brightness regulations, possibly the most groundbreaking feature on BMW’s highly innovative i8 plug-in hybrid isn’t legal in the United States. That’s right – no laser headlights for us. And get this: BMW says its lights are 30 per cent more energy-efficient than LEDs and illuminate up to double the distance, about (600 metres).

“They aren’t as precise as LEDs, though, so the i8 still uses that technology for low beams. Along with increased brightness and photon density, laser lights also allow for more compact packaging.”

He goes on to say that BMW beat its rival to market by being the first to make sure the whole set-up could withstand the harsh vibrations and extreme temperatures a car encounters during its lifetime.

His lament: “Too bad we won’t get to test them out anytime soon. Have you sent that e-mail yet? “

How it works (see image 4). Laser diodes create three separate beams of blue laser light. The beams are directed through a prism, merging into a single beam. The concentrated beam passes through a phosphorous lens that yields a diffuse white light, which is safer for human eyes. The white beam bounces off a reflector and past a clear lens onto the road.