Laser light in cars – throwing light on a safer future
Dr. rer. nat. Carsten Setzer (Spokesperson)
Dipl.-Ing. Christian Amann OSRAM GmbH, Munich
BMW Group, Munich
Far more traffic accidents occur at night than during the daytime. Due to poor lighting conditions, drivers often recognize hazards too late, which considerably increases the accident risk. How can traffic safety at night be improved?
The answer was obvious to Dr. Carsten Setyer and Christian Amann: the luminance of the high beam setting must be improved to provide a level of visibility equivalent to daylight. The nominated engineers and their teams developed a system that meets this requirement and has been introduced in the first series vehicles in the meantime. The heart of the system is a laser light source that produces a bundled white laser of high intensity and efficiency. Carsten Setzer is Head of Automotive Lamps at OSRAM GmbH in Munich, Christian Amann is Head of Lighting Systems at the BMW Group in Munich.
During the development of the light source for the world’s first laser headlight, the two managers and their teams had a paradox to overcome that initially seemed insolvable: on the one hand, a laser is a virtual dot-shaped - and thus an ideal - source of light, but in principle it only produces a monochromatic light of a certain frequency. On the other hand, white light is needed for headlights. But white light is a mix of several colors – and a laser is never white. To solve this conundrum, the scientists resorted to a trick known in theory but not yet industrially implemented: they focused the light of a blue laser onto a special ceramic which converted part of it into yellow light. By mixing the yellow and blue light components, they succeeded in producing a focused dot of white light the diameter of which was not much larger than that of the original laser.
To realize this ingenious approach, the experts on Dr. Carsten Setzer’s team at OSRAM had to first realize several fundamental technical components of the laser light source. One of the components is a wafer-thin highly efficient ceramic fired at 2000°C and used for light conversion. All previously known so-called conversion materials were not able to withstand the intensive blue laser beam or became so hot that light conversion was no longer possible.
Moreover, the scientists developed and validated all processes and systems used to produce the light source pursuant to the demanding standards of the automotive industry.
The headlight designers on Christian Amann’s team integrated the bright white light source in the headlights of a BMWi8. They significantly improved driver visibility after dark in the hybrid introduced to the market in June 2014. Amann and his team also added a special safety system to the extremely bright high beams. The system ensures that the laser headlights automatically switch off in the event of an accident or technical malfunction – preventing the blue laser to which the human eye is especially sensitive.
Well over a year after launching the laser headlight in the BMW i8, BMU introduced the first large-series vehicle to use laser light in their new BMW 7 series models at the International Motor Show IAA in Frankfurt in September 2015. The range of the highly luminous laser headlight is 600 meters. It is designed to complement a conventional LED high beam that lights up the road to a distance of 300 meters. The no-dazzle high-beam assistant ensures that oncoming traffic and vehicles traveling in front of the car are shielded from the light cone and not blinded by the high beams. The technology has caused a sensation in the industry and has allowed OSRAM to safeguard numerous jobs in Germany. The company also has plans to expand production capacity significantly. The aim is to serve the up-and-coming market for white laser light in which strong growth is expected as of 2018.
The conscious decision to put a new technology on the market has paid off. OSRAM and BMW are the market leaders and with their pioneering work have opened up the market for other applications.