Volkswagen Magazine

Innovation

Better, brighter, broader.

From a turn signal that projects onto the road to individual lights for everyone: LED technology opens up new possibilities for engineers and designers. It’s already available today in many Volkswagen models.

Text Marc Lüttgemann
Infographic C3 Visual Lab

The headlight looks almost baroque, as if from a classic car: oval shape, very wide, very low. And yet modern, not least because it has no bulbs, but instead small rectangular dots that are the source of light in the interior. What is it that Dr Gunnar Koether, Head of Lighting and Vision at Volkswagen, is holding in his hands? “This,” he says, “is the first LED headlight from Volkswagen, built in 2005.”

An artefact, then, both historic and futuristic. Historic because it comes to us from the early years of working with this light technology. Even back then, it was clear to engineers like Koether that LEDs – the acronym stands for “light-emitting diodes” – held great appeal for use in cars. LED technology is more energy-efficient than halogen and xenon, and for less energy consumption you get a more variable and more designable light. Unlike with its predecessor technologies, the illumination does not emit from a single source that is directed and distributed by reflectors and lenses.

Instead, a headlight is comprised of many individual LEDs, opening up a range of new design possibilities – such as the characteristic strip lights – for front and rear lights. The transition is highly evident on our roads – cars with individual, LED-based light design are easy to spot. The first Volkswagen with LEDs was the XL1, followed by the e-Golf. Today many models from Volkswagen are available with LED technology, from the Touran, Multivan and Tiguan to the Passat. LED technology is even available for the Polo. “And it’s no secret,” says Koether, somewhat inaccurately, “that we will soon be offering LED technology in additional variants of the Golf. That’s one of our strengths at Volkswagen – that we make state-of-the-art technologies available to the wider mass market.”

It started with the XL1, now even the Polo has LEDs.

Comparison: the light
from the Passat in 1988 and 2015

Views from the driver perspective show that the halogen dipped beam in the Passat B3, built from 1988 to 1993, emits a more flat and narrow light than the LED dipped beam in the current Passat B8.

LED headlights
in detail

LED light is an example of that, and the current high point in a very dynamic development in the field of lighting over the past few decades. While for a long time “not much happened” following the adoption of halogen lights in the 1960s, as Koether explains, the pace of innovation has accelerated strikingly since the 1990s. Xenon technology was the first step forward. In xenon lights, a xenon arc between two tungsten electrodes burns and thus produces illumination. After that, more and more assistance systems such as dynamic cornering lights improved the capabilities of headlights and increased driving safety. Volkswagen developed the masked Dynamic Light Assist technology that made its début in the Touareg in 2010, and was the only such technology on the market for two years.

The technology ensures that the road is always optimally illuminated without the driver needing to manually adjust the lights. The function relies on a camera installed behind the windscreen. If it detects oncoming traffic and thus the potential for dazzling other drivers, it switches to low beams in that range. But the road remains well illuminated for the driver.

As the masked Dynamic Light Assist technology demonstrates, a light today is much more than just a headlight. Lighting in cars is networked; it has to communicate with other areas in the vehicle – for example when it comes to recognition of traffic signs, where on the one hand light is necessary to recognise the sign, but on the other will in future automatically dim in such situations to avoid the strong reflections produced by high-performance LED systems.

Light technicians today work more closely not only with planners and programmers, but also with designers. Koether explains, “Previously, we had a known and defined light source, and the headlight was designed around that. Today this takes place in a dialogue because there are so many more possibilities.”

Comparison: light from
the Passat in 1988 and in 2015

The bird’s-eye view of the light cone shows that areas adjacent to the road in particular are much better illuminated with LED technology.

The click-clack light from the Passat: The horizontal LED arrangement during normal driving (left) switches to a vertical arrangement when the driver brakes (right).

» The are so many more possibilities in light development.«

Dr Gunnar Koether

One development that demonstrates what is possible at the interface between aesthetic design and smart technology is the click-clack rear light on the Passat. Here the lighting during normal driving is a horizontal row of LEDs. If the driver brakes, the shape changes, and the horizontal line converts into a vertical one. That has a greater attention-grabbing impact for the driver behind and thus improves traffic safety. “It’s possible because with LED technology we can control individual light points. That is the great leap that’s been made from halogen and xenon to LED,” explains Koether.

That the future belongs to LED is widely accepted among experts. “LED technology will keep us busy for some years yet. There’s still a lot of untapped potential there,” explains Professor Cornelius Neumann, head of the Light Technology Institute at the Karlsruhe Institute of Technology. When Koether talks about the possibilities of LED technology, he likes to present concrete examples: a LED, for example, that projects a turn arrow for the driver onto the road when the navigation system indicates that a turn is forthcoming.

Or one that clearly marks the lane with a light corridor. Or highly individualised light, such as multiple dipped-beam variants, because every driver perceives light differently and has different preferences. “But of course you have to test things very precisely to find out whether technologies such as the turn arrows or illuminated lanes would disturb other road users,” Koether cautions.

LEDs are the technology of the hour, yet light technicians and researchers like Koether and Neumann are already working on what will one day replace or enhance LED technology. Neumann suggests lasers and points out some advantages. “Thanks to its high intensity and minimal expansion, laser light presents designers with new opportunities.” This would be an option for sports cars in particular. Koether, meanwhile, is thinking about OLEDs – organic LEDs. Here, too, Volkswagen has already been developing prototypes, including with curved OLEDs in an interior light. The pace of innovation in lighting will remain rapid for some time to come.