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Gold Nanosponges and a Thousand LEDs Make Efficient, Adaptive Headlights

Fraunhofer's headlights use an array of individually addressable LEDs to efficiently illuminate only the parts of the road you care about

2 min read
Gold Nanosponges and a Thousand LEDs Make Efficient, Adaptive Headlights
The µAFS team shows off its advanced headlamp system's ability to direct beams with a high degree of specificity.
Photo: Osram

Conventional headlights are extraordinarily wasteful. In order to light up your side of the road, they end up illuminating a bunch of other side of the road (including the eyeballs of other drivers), as well as a significant chunk of the sky—and trees and houses and garden gnomes and lawn flamingos—for no good reason. Won't somebody please think of all of those poor photons, zipping uselessly off into random directions?

Fortunately, the Fraunhofer Institute is very concerned about the fate of photons. They've designed a new type of headlight that illuminates the road ahead better than ever before, using a thousand LEDs—70 percent of which are usually kept in photon-saving mode. That is, turned off.

The ideal headlight would brightly illuminate what you care about, and leave everything else in darkness. We've seen headlights that use lasers or DLP systems to dynamically target and adjust light output, but even those are less efficient than they could be, because they operate by selective occlusion. In other words, the headlights are producing light that they then immediately block, effectively wasting it and leaving the jilted photons feeling useless and depressed. Another option has been to use an array of larger LEDs (typically about 80 of them), with each one hooked up to some expensive and finicky optics.

Fraunhofer's solution is to use a 1024-LED array, with each “pixel” sized at 125 micrometers. The LEDs (which emit 3 lumens each) can be individually controlled, which allows the headlight to selectively distribute the light that it projects at an unprecedented resolution. For example, one headlight is capable of illuminating the road ahead, curves, parked cars, upcoming street signs, and whatever else you want, all at high beam brightness while intelligently avoiding searing the eyeballs of oncoming drivers. Fraunhofer says that on average, only 30 percent of the pixel array needs to be active at once, resulting in a significant efficiency improvement over other LED headlights.

imgNanoporous gold sponge creates reliable contacts.Image: Fraunhofer

This new headlight is the result of a collaborative project called µAFS (for micro Adaptive Front-Lighting Systems), which also involves Infineon, Osram, Hella and Daimler. One particularly tricky part of making this thing work was finding a way to reliably make the 15-µm connections needed to control each one of those LED pixels. The solution to this (and, indeed, to most other problems) was a sponge. This particular sponge is a nanoporous structure made of gold that can be compressed so that it adapts itself to the topography of whatever component you're squishing it against—quickly and easily compensating for any unevenness which might otherwise cause problems. 

Beyond mentioning that “the LED chips are currently installed in headlights,” Fraunhofer hasn't said much about when we might expect to see some sort of commercial product. What we can expect is that whenever such a commercial product does become available, it's going to show up first in a Mercedes, meaning that those of us who work for nonprofits will be able to take advantage of them closer to later than sooner.

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We Need More Than Just Electric Vehicles

To decarbonize road transport we need to complement EVs with bikes, rail, city planning, and alternative energy

11 min read
A worker works on the frame of a car on an assembly line.

China has more EVs than any other country—but it also gets most of its electricity from coal.

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Green

EVs have finally come of age. The total cost of purchasing and driving one—the cost of ownership—has fallen nearly to parity with a typical gasoline-fueled car. Scientists and engineers have extended the range of EVs by cramming ever more energy into their batteries, and vehicle-charging networks have expanded in many countries. In the United States, for example, there are more than 49,000 public charging stations, and it is now possible to drive an EV from New York to California using public charging networks.

With all this, consumers and policymakers alike are hopeful that society will soon greatly reduce its carbon emissions by replacing today’s cars with electric vehicles. Indeed, adopting electric vehicles will go a long way in helping to improve environmental outcomes. But EVs come with important weaknesses, and so people shouldn’t count on them alone to do the job, even for the transportation sector.

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