BMW develops laser-based headlight technology
BMW said its engineers are already working on the introduction of laser light for series production within a few years. Laser light could facilitate entirely new light functions for more safety and comfort and at the same time contribute significantly through its higher degree of efficiency towards a saving in energy and fuel respectively.
Laser light produces virtually parallel light beams. Thus it is different from sunlight, and also from the various types of artificial lighting in common use today. Because laser light is monochromatic and coherent, laser lighting can produce a near-parallel beam with an intensity a thousand times greater than that of conventional LEDs. In vehicle headlights, these characteristics can be used to implement new functions. Also, the high inherent efficiency of laser lighting means that laser headlights have less than half the energy consumption of LED headlights.
BMW said for safety reasons the light is not emitted directly, but is first converted into a form that is suitable for use in road traffic The originally bluish laser light beam is converted by means of a fluorescent phosphor material inside the headlight into a pure white. Thus, the intensity of the laser light poses no possible risks to humans, animals or wildlife when used in car lighting, the company explained. The resulting bright white light is described it as "very pleasant to the eye" and generated with very low energetic effort.
Laser lighting technology is already in use in a variety of consumer products, though in many cases this is a product feature that goes unnoticed by the customer. That won’t be the case when this technology is used in cars, however, as planned by BMW. Here the whole point is that the advantages should be noticeable and visible.
An important feature of laser technology is the size of the individual diodes. With a length of just ten microns (µm), laser diodes are one hundred times smaller even than the small, square-shaped cells used in conventional LED lighting, which have a side length of one millimeter. This opens up new possibilities when integrating the light source into the vehicle. The BMW engineers have no plans to radically reduce the size of the headlights however, although that would be theoretically possible. Instead, the thinking is that the headlights would retain their conventional surface area dimensions and so continue to play an important role in the styling of the car, while the size advantages could be used to reduce the depth of the headlight unit, and so open up new possibilities for headlight positioning and body styling.
A further advantage of laser lighting technology, and one which the BMW engineers intend to use to full effect, is its high inherent efficiency. A single statistic will make this clear: whereas LED lighting generates only around 100 lumens (a photometric unit of light output) per watt, laser lighting generates approximately 170 lumens. Its first airing will the laser lighting system get in BMW’s new i sub-brand, a brand the company created to test new concepts for a more sustainable mobility.
The company hinted that there are considerations to use laser light in the future to implement all familiar lighting functions such as Adaptive Headlights or the company’s Dynamic Light Spot spotlighting system. It will also be possible to use laser lighting to implement completely new functions, which will have only minimal power consumption. The company however declined to elaborate on the kind of these new functions.