Sam Davis
Power Electronics
In the coming years, a vehicle’s lights will serve to improve safety as well as offer a means of communication and interaction
“We’re working hard to improve safety in night driving situations,” remarks Mathias Thamm, head of Volkswagen’s Technologies and Innovations sub-department. He says that it’s important because about 30% of all accidents involving personal injury occur at night, and accident severity is much higher than during the day. Moreover, as the number of daylight hours shrink at the end of the year, these incidents become even worse.
Headlights are a major factor in providing a safe environment for night driving. Early generations of Volkswagen’s Golf had halogen headlamps that became brighter and brighter. These were followed by first xenon headlamps, then LED tail lamps, LED daytime running lights, and now LED headlamps.
Volkswagen partnered with German-based auto parts producer Hella to develop the IQ.LIGHT LED headlamps. Volkswagen is always available to offer novel lighting systems. The new luxury class Touareg SUV uses the IQ.LIGHT – LED Matrix Headlamps.
These adaptive matrix headlamps (Fig. 1) employ a targeted control of up to 128 LEDs to provide precise and optimal light distribution and luminous intensity. Volkswagen contends that compared to conventional lighting systems, the LED Matrix Headlamps will enhance safety and comfort because they will allow drivers to recognize road details and possible obstacles at night earlier, giving them more time to respond.
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| Figure 1. | These IQ.LIGHT LED matrix headlights are interactive, camera-based dipped, and have main beam headlight control. |
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The headlamps have individually controlled LEDs that blend into a matrix of light areas in both the high and low beam modules. The low beam employs a matrix of 48 LEDs positioned on a shared circuit board. The high beam circuit board uses 27 LEDs. Combined, these 75 LEDs form the adaptive matrix light.
Another 53 additional LEDs ensure that lighting functions can be shown, including the illumination in front of the vehicle, as well as the daytime running lights, the cornering lights, the position lights, and the direction indicators. In total, the front lamps of the new Volkswagen Touareg will use 256 LEDs.
Assisting the headlamps is a front digital camera that analyzes road conditions, spots oncoming vehicles, etc. That data combined with GPS data, along with speed, and steering angles will go into selecting the LEDs in the matrix to provide the ideal headlamp illumination for the road and the surrounding area up ahead in less than a second.
The camera-based system reacts to signs by temporarily dimming the LEDs to avoid causing glare for drivers themselves. The camera can’t detect the wet road. The driver has to manually activate the bad-weather light function.
In the Touareg, the LED Matrix Headlamp system performs the LED selection and illumination within the headlamp matrix automatically using “Dynamic Light Assist.” It turns the LEDs on and off independently and adjust the lights to the current environment, topography, and traffic situation.
This aggregate of data allows the car to recognize the driving location on a city or a country road, on the highway, or off-road, and will anticipate where other road users might currently be located. The system supports the driver with the best possible lighting without bothering other road users.
The IQ.Light LED matrix headlamps offer the following capabilities:
- City light: Particularly wide light beam focused on the sides; active up to 50 km/h.
- Country road light: Low beam with broad light distribution toward the roadside.
- Masked Dynamic Light Assist: Dynamic Light Assist on country roads without dazzling other road users.
- Highway low beam: Narrower beam, focused on long range at higher speeds.
- Highway high beam: Narrower beam focused on long range at high speeds as soon as no other road users are dazzled.
- Overtaking light: Precise high beam for overtaking without dazzling. The system detects that the vehicle is veering sideways; this side area is now more strongly illuminated.
- Passing light: Right-hand accentuation of the roadway when driving with masked Dynamic Light Assist and oncoming traffic is approaching. The view is thereby directed more to the driver’s own lane.
- High beam: Manually activated high beam to deliberately use all of the headlamp’s 75 LEDs for maximum illumination. This light beam is wider than for the highway high beam.
- Bad-weather light: Reduces the amount of glare at night from the vehicle and from other vehicles on wet roads. The distracting reflections of the headlamp light on the wet reflective road surface directly in front of the vehicle are reduced by the “IQ.LIGHT” that reduces illumination intensity in this area. In addition, the roadway is illuminated more broadly. The driver can activate or deactivate this function.
- Sign glare control: Precise dimming of the high beam on signs so that the reflected light from the headlamps doesn’t dazzle the driver.
- Off-road light: Particularly powerful static low beam headlamp, fanned out to a 90-degree angle so that obstacles in the area can be better recognized.
- Marking light (for “Nightvision”): Focused illumination of the people detected by "Nightvision” (infrared camera) without dazzling, making it easier for the driver to recognize them.
- Sequential cornering light: Enables an optimum light distribution width to be generated in many of the above-mentioned light distributions through selective switching on, switching off, and various dimming levels. In addition, when a turn is made, the light is quickly “fanned out” and slowly “fanned in” again.
Light Tunnel
To prepare for present developments and future challenges, Volkswagen opened its own lighting competence center at its Wolfsburg (Germany) plant in 2014. There, a 100-meter-long, 15-meter-wide, 5-meter-high light tunnel has been in operation in the middle of the R&D department (Fig. 2). In this tunnel, the lighting systems of today and tomorrow are tested on a real road simulation. The tests can be repeated and reproduced with total precision. Systems can be compared and evaluated in a light tunnel better than ever before.
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| Figure 2. | The light tunnel at the factory in Wolfsburg. | |
The competence center is also an ideal place to investigate the light perception of drivers and passers-by. In addition, interior systems such as ambient lighting, head-up displays, and infotainment systems can be tested here under reproducible conditions. The light tunnel also shortened the development time for new headlamp, tail lamp, and interior lighting systems, as the number of time-consuming night drives could be reduced. This allows advances in lighting development to be implemented even more quickly into series production technologies.
