FLINGING the curtains open to find sunlight flooding in is often enough to put a spring in your step. Soon you will be able catch some sun even when it鈥檚 pouring with rain, thanks to a lighting panel that uses nanoparticles to recreate something close to natural daylight. Even the dank, windowless interiors of shopping malls and underground stations could get a welcome dose of blue skies.
聯Even the windowless interior of a shopping mall could soon get a welcome dose of blue skies聰
The setup, developed by at the University of Insubria in Como, Italy, and his colleagues, uses white LEDs as its source. The LEDs shine through that scatter light in the same way as Earth鈥檚 atmosphere does with sunlight. Different panels can simulate various outdoor light conditions 鈥� from a bright sunny day to a gorgeous sunset or even the brooding skies of a storm.
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The idea, says di Trapani, is to help 鈥渢he rapidly increasing fraction of the population who spend more and more of their time deprived of natural lighting鈥�.
By , the team managed to mimic the physics of Rayleigh scattering, the process by which air molecules scatter the sun鈥檚 radiation. Two different sizes of nanoparticles, clustered in different sections of the plastic, separate white light into diffuse 鈥渟ky light鈥�, in which blue wavelengths are dominant, and a bright spot of warm, yellowish light just like direct sunlight.
The prototype panel, which is 1.8 metres long and 85 centimetres wide, was unveiled last month at a lighting exhibition in Frankfurt, Germany. The team plans to market the panels through a University of Insubria spin-off called .
鈥淲e hope it will be a game changer, whether it鈥檚 in road tunnels, malls, hotels or hospitals,鈥� says di Trapani.
The rise of cheap and efficient LEDs has prompted others to explore novel ambient lighting as well. Last month, Philips of the Netherlands launched , a luminous textile-based LED panel that can cover whole ceilings or walls with soft, homogeneous white light.
鈥淏ecause the panel has no apparent central light source it feels like you are outdoors, lit by the sky,鈥� says Antoon Martens of the Philips project. 鈥淚t feels serene, clean and cool, as if you are outside.鈥�
This article appeared in print under the headline 鈥淚 got sunshine on a cloudy day鈥︹��
