Lighting technology is a field in which Audi is well ahead of the competition. The brand already offers LED headlights in many model series, and groundbreaking Matrix LED technology is now available in the new Audi A8. Audi's next steps will be laser headlights for the high beam and innovative interior lighting.
Lighting technologies of today
Design and technology – the headlights of every Audi car are a visible expression of Vorsprung durch Technik. They define the appearance of the cars, and because they illuminate the road so well, they also make a major contribution to active safety. With its numerous innovations, Audi has raised the profile of lighting technology in the international automotive industry.
In 1994, xenon headlights in the Audi A8 replaced the halogen lamps typically used. The sedan added adaptive light and LED daytime running lights in 2003 and 2004, respectively. Audi established another milestone in 2008 with the introduction of all-LED headlights in the R8 supercar. Today this technology is available in numerous models, including the A3 family. In 2010, the adaptive light was networked with navigation data for the first time in the Audi A8.
With adaptive light, which is available in a variety of configurations, a control module controls the swiveling xenon plus modules so that they always deliver the ideal illumination for city, highway and freeway driving. The driver can configure the swivel characteristics via the Audi drive select vehicle dynamics system. The all-weather light in the main headlights replaces the fog lights and provides for a longer range, a wider lateral illumination pattern and reduced glare.
A particularly attractive component of the adaptive light is the variable headlight range control. A video camera recognizes preceding and approaching vehicles by their lights. The control module then adapts the car’s lighting to the distance to the other vehicles – via a soft transition that always maximizes the amount of illumination.
Networking with the MMI navigation plus system makes the adaptive light even more capable. The navigation system reads the route data in advance and relays them to the light computer so as to activate the highway lighting while still in the approach lane, for example. The system automatically switches on the cornering lights before entering an intersection, and in countries like the United Kingdom, it automatically switches the headlights from driving on the right to driving on the left.
LED daytime running lights and LED rear lights
Daytime running lights comprising white light emitting diodes are available in different designs for each model The Audi A1, for example, uses two LEDs per headlight. They emit their light into a transparent polymer tube, the light guide, which generates a uniform contour. In the Audi A7 Sportback, the daytime running lights of the optional LED headlights also appears to be linear, but are generated by 18 individual LEDs behind a polymer body.
Audi also offers rear lights using LED technology either standard or as an option for all models. They produce a distinctive light pattern that in many cases also produces three-dimensional effects. The light-emitting diodes reach their full light intensity almost instantaneously – if a driver has to brake suddenly, drivers following the Audi gain valuable fractions of a second.
Dynamic turn signals
Audi offers dynamic turn signals in the R8 and the A8. In the sedan, a strip of 18 light-emitting diodes divided into seven blocks is located at the bottom and outer edge of each headlight. In each of the rear lights, there are 24 LEDs in eight segments.
When blinking to signal a turn, the blocks are sequentially activated at 20 millisecond intervals, from the inside outwards. After 150 milliseconds, all segments are bright; For another 250 milliseconds they illuminate with full intensity. The turn signals then go dark before repeating the lighting sequence. Because the new Audi turn signals also visualize the turning direction, they send an intuitive signal that can be quickly recognized even at a great distance.
LED headlights from Audi produce a light that, with a color temperature of around 5,500 Kelvin, resembles daylight and is thus easier on the eyes. The LEDs are maintenance-free and designed to last the life of the car. The low beams consume only around 40 watts per unit, somewhat less than the already highly efficient xenon plus headlights. The LED headlights have special features for the city, intersections and interurban roads as well as for freeway driving, left-hand traffic and poor weather.
Audi showcases the technology's beauty with the design of the LED headlights. In the A3 series, eight high-performance LEDs in the matte aluminum trim provide the high beams; nine high-performance LED chips in two free-form reflectors generate the low beams. The static turning and all-weather lights are housed in a separate module, and the daytime running lights, parking lights and turn signals are generated by a light guide that runs as a narrow strip along the upper and inner edge of the headlights.
LEDs do not get particularly hot. Red light-emitting diodes reach about 120 and white ones 150 degrees Celsius – much less than halogen headlights, which generate temperatures of up to 400 degrees Celsius. Fans ensure that the heat of the LEDs is transmitted to the headlight glass to keep it as free as possible of snow and condensation in Winter.
In the Audi A8, the LED headlights interact with the optional night vision assistant to provide an additional function which helps to ensure even greater safety. When the night vision assistant detects a person in the critical area in front of the car, individual LEDs blink three times in quick succession. This highlights the person against the background, warning both them and the driver.
Audi Matrix LED headlights
The Audi Matrix LED headlights in the new A8 made their debut at the International Motor Show (IAA) in Frankfurt and represent the cutting edge of production technology. Their light, which has a specific shine, always delivers excellent illumination without blinding other road users. The high beam is broken up into 25 small light-emitting diodes per headlight. Groups of five shine through a common reflector.
When the light switch in the Audi A8 is set to Automatic and the high beams are on, the system is switched on outside of urban areas at speeds of 60 km/h (18.64 mph) and above. As soon as the camera used by the high beam detects another vehicle, the new headlights switch off or dim individual LEDs in the blink of an eye. Oncoming and preceding vehicles or road users are excluded from the light pattern and are not blinded, while all other areas between and adjacent to them continue to be fully illuminated. As soon as the oncoming traffic has passed, the high beam once gain illuminates the previously excluded sectors with full power.
The LEDs in the Matrix LED headlights also assume the function of cornering lights, selectively brightening or dimming to shift the focal point of the light along the curve. They do this shortly before the wheel is turned based on predictive route data provided by the MMI navigation plus. The light guides the driver into the curve.
Lighting technologies – outlook
Audi is already developing the lighting technologies of tomorrow. Three central themes are emerging. The Audi lighting of the future will react even more intensively to environmental conditions, it will communicate in various ways with its surroundings and thereby help to further increase active safety. With the Matrix LED headlights, Audi has already indicated that the lighting of the future will feature full-electronic control, making new dynamic features even more versatile.
Laser high beams
The laser light, which Audi is unveiling at the 2014 CES as the next step in headlight technology, has the potential to complement the LED high beam. It will make its debut in Audi's new Le Mans race car in June 2014, continuing the brand's tradition of testing its new technologies on the race track, the world's toughest proving grounds.
Laser diodes emit a monochromatic and coherent light with a wavelength of 450 nanometers. In its natural form it has a bluish shimmer. A phosphor-coated film in front of the diode converts it into a white light suitable for automotive applications. Just a few micrometers in diameter, the laser diodes are even smaller than LED diodes and come very close to the theoretical ideal of a high-output, point light source for use in cars.
In the Audi Sport quattro laserlight concept show car, which Audi is displaying at the CES, the high beam produced by the laser diodes is three times as bright as the LED high beam. With a range of nearly 500 meters (1,640.42 ft), it reaches nearly twice as far – a major safety plus for the driver. Because the light beam is tightly bundled, laser diodes are not currently suitable for wide, low-beam light.
Interior lighting scenarios
There are many aspects to interior lighting. First, it provides functional value by making it possible to read and work at night and to find objects in storage compartments. But interior lighting is more than just functional; it contributes to a sense of well-being in the cabin and stirs emotions. The ambient lighting in the Audi A8 is a particularly successful example of this. In the near future, interior lighting developers will be able to add additional aspects: interaction with the surroundings and communication with the driver. The light will become part of the HMI (human-machine interface), the car's interface with the person.
Audi's LED and OLED technology is ideally suited to this purpose. Small diodes could illuminate the steering wheel rim, for instance. A green light could indicate to the driver that piloted driving is active, and red light could be a call for increased attentiveness at an intersection, for example. A red light in the door liner could warn against opening the door because a cyclist is about to pass. The wrap-around, the long arc below the windshield in many Audi models, could assume similar functions.
In the medium term, Audi plans to link intelligent interior lighting to innovative exterior lighting. In this scenario, lights on the driver's door and its door handle would switch on as the driver approaches the car. When the driver gets in, the light follows them into the cabin, tracing important contours such as the steering wheel and the instrument cluster.
The Solunar study
With the Solunar study, Audi demonstrates the custom use of light in the cabin. It provides insight into the subject of light in an urban context and presents ideas and technologies for the customization of light in the automobile. Solunar uses light throughout the entire cabin and even in the floor of the car. It adapts to the driver's style. The cabin becomes brighter while driving slowly in urban traffic and is more darkly illuminated during fast freeway driving. The light also takes on interface functions vis-à-vis the driver. One possibility is a turn arrow on the carpet as navigational information. One unique feature is the linking of interior lighting with innovative exterior lighting. For example, the marker light in the cabin passes into the engine hood to become exterior lighting.
The equipment and data specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.