Headlights have come some way since the oil lamps used in the 1880s. Adaptive headlights, along with emerging systems that light up potential hazards and follow the driver's eye give some indication as to what lies ahead. Now researchers have developed a system that allows even more precise control through the ability to switch on and off any of 1,000 individual LED pixels.
Existing adaptive headlight designs rely on up to 100 separate LEDs to provide individual sources of light, each with their own precisely aligned optics. Now, researchers at Germany's Fraunhofer institute have worked out a way to up this resolution to more than 1,000 LEDs, while still maintaining control over each individual pixel.
They were able to achieve this by connecting 256 pixels across four separate LED chips to a driver chip. Working with pixels 125 microns in size, they team discovered two ways to do this while ensuring a solid connection and sufficient cooling of the chip. The first technique involves a gold-tin alloy fitted to the chip in a fine grid structure with intermediate distances as small as 15 microns. The second approach instead relies on a gold, porous nano-sponge that can compress just like a regular sponge, allowing it to absorb any unevenness in the chip.
"This nanoporous gold structure has the advantage that it compresses like a real sponge and can be precisely adapted to the topography of the component," says Fraunhofer's Dr Hermann Oppermann.
The resulting adaptive headlight allows a permanent high beam, results in less blinding glare for other road users and also enables finer control over light distribution. It also holds the promise higher energy efficiency compared to others that use mechanical masks for adaptive lighting, as only the pixels that are needed are switched on, something the researchers claim is typically around 30 percent of the total available output.
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