More safety: Smart automotive lighting
How can headlights illuminate the road perfectly without blinding other traffic? For decades, the solution was to switch manually between high and low beam — until technological developments made an automatically responding matrix headlight possible. Scientists are now conducting further research in order to create a headlight that will respond even more sensitively, thanks to liquid crystal shutters from Merck KGaA, Darmstadt, Germany.
To see and be seen: When physicist Christian Schmidt, Head of Advanced Lighting Technology Development at Hella, demonstrates the headlight of the future, it seems to be a cross between a projector and a video game. In the 140-meter-long light tunnel at the lighting specialist Hella, the beam of light cuts through the initial darkness to project letters and patterns onto a screen. “The headlight of the future will provide drivers with maximum illumination while optimally ensuring that oncoming drivers, cyclists, and pedestrians are not dazzled,” says Schmidt enthusiastically about the headlight project, which will run until March 2017.
Christian Schmidt, Head of Advanced Engineering for lighting technology at Hella
© Merck KGaA, Darmstadt, Germany
The aim is to create nothing less than “smart lighting” for automobiles. The German Federal Ministry of Education and Research (BMBF) is covering almost half of the costs of a €4.4 million research project that has brought together six players from business and science in order to invent the headlight of the future. The participants include Hella, Porsche, Paderborn University, and Merck KGaA, Darmstadt, Germany. They are all contributing their skills and requirements to the project in order to develop a fully adaptive light distribution system for smart, efficient and safe automotive headlights. The system could become available in 2020.
Although this might sound complicated, it describes precisely what the project is about, since these innovative technologies will ultimately lead to the development of cutting-edge vehicle headlights that will improve traffic safety.
The history of car lights: From candles to matrix headlights
Producing cutting-edge vehicle headlights has been Hella’s aim ever since it was established to manufacture bicycle and wagon lamps in 1899. Based in Lippstadt, Germany, the leading automotive supplier has increased its workforce over the years from 30 employees to more than 32,000 today. The company owns a few examples that show how automotive lighting has developed from the petroleum lamp all the way to the HD84 matrix headlight, which contains light-emitting diodes (LEDs) and was launched on the market only recently, in spring 2016. These two devices are separated by 120 years of research that focused mainly on improving illumination and non-glare properties, as well as adapting this component to the needs of car designers.
“LCs enable us to automatically control light distribution fully electronically and with high resolution.“
“In 1924, Osram introduced the bilux headlight lamp, which could be switched between high beam and low beam. For many decades, this lamp was, in principle, the state of the art,” says Christian Schmidt. Although high beams illuminate the road well, they blind oncoming drivers. If drivers switch to low beam, they no longer dazzle other road users, but cannot see as well.
The goal: Maximizing visibility without dazzling
Might it not be possible to develop a headlight system that automatically ensures good illumination without dazzling? Developers have been addressing this question ever since the bilux lamp was introduced. “Many groundbreaking ideas for vehicle headlights were developed before it was technologically possible to create them,” says Schmidt. A good example of what he is referring to is a patent by the computer pioneer Konrad Zuse, who in 1958 invented a “dazzle-free high beam,” in which several headlights illuminated the road simultaneously. Zuse intended the system to automatically detect oncoming traffic and shut off those lamps of the headlight matrix that would dazzle other road users.
With light-based driver assistance systems, the drivers of oncoming vehicles are not dazzled by a headlamp on high beam
However, this revolutionary idea was not realized until two generations later, when white light-emitting diodes were combined with a windshield-mounted camera and an image recognition and processing system. “The HD84 headlight system that we introduced in 2016 uses three rows of LEDs and can automatically control each LED individually,” says Schmidt, describing the current state-of-the-art technology.
The research project is now further developing this approach to create the headlight of tomorrow. The idea is to drastically reduce the number of light-emitting diodes to about one third of the former amount and use a liquid crystal (LC) shutter to control the distribution of the light completely electronically. “It provides us with tens of thousands of pixels that we can use to automatically control light distribution fully electronically and with high resolution,” says Schmidt, pointing to a small box that contains the development sample which exemplifies the sector’s maxim, “lighting goes digital.”
Low temperatures present the greatest challenges
Among the system’s core elements are the LC shutter’s liquid crystals, developed by Merck KGaA, Darmstadt, Germany. In cars, the shutter has to operate flawlessly at temperatures ranging from -40 degrees Celsius to +120 degrees Celsius. “Low temperatures present us with the greatest challenges,” says Michael Wittek, manager of the headlight project at Merck KGaA, Darmstadt, Germany. To enable the shutter to withstand intense cold, the company had to create a new mixture out of approximately 20 different compounds.
Michael Wittek heads the project for liquid crystal shutters at Merck KGaA, Darmstadt, Germany
© Merck KGaA, Darmstadt, Germany
In addition to greater safety, the new headlight technology will provide car designers with more freedom. According to Schmidt, this is because “the development of car lighting systems always begins with a design model.” And what can we expect even further in the future? “We’re thinking of networking vehicle headlights with street lighting, for example,” replies Schmidt.
“One of these compounds was, in fact, used in LCs for the very first time,” adds Wittek. The automotive industry also has higher demands than the consumer goods industry, for example, when it comes to longevity. “LCs have to last for at least 15 years in automobiles, in spite of often tough and changing environmental conditions,” says Wittek.