The light fixtures that mimic natural light

CoeLux is one of the World Economic Forum’s 2015 class of Technology Pioneers. The company uses nanotechnology to produce ceiling LED fixtures that people cannot tell apart from an aperture onto a sunny sky. Professor Paolo di Trapani, founder and CEO, explains how it could transform architecture and the human experience of indoor spaces.

How does the CoeLux skylight differ from other light fixtures that try to mimic natural light?

Essentially, by also creating the feeling of space. When people look at CoeLux skylight, they have the feeling they are looking upwards through tens of kilometres of space.

When we first demonstrated the product at an exhibition, we noticed that people who entered our booth were often looking around wondering what product we were demonstrating. When we pointed up to the skylight, they simply assumed it was an opening to the outside. We had to work hard to convince them that it was not, in fact, the actual sky, by reminding them that we were deep inside a windowless exhibition centre.

How do you create this feeling of looking into space?

The natural light that we experience outdoors is the result of the directional sun’s waves passing through the earth’s atmosphere. As it does so, it interacts with air molecules, water droplets or other various particles in the atmosphere, diffusing the light that reaches us and changing its quality in many different ways. If you were to experience the sun from the moon, without earth’s atmosphere, it would look quite different.

What we have done is understand the processes that sunlight undergoes as it passes through the atmosphere, and recreate the same physics on a smaller scale using nanoparticles. CoeLux skylights involve an LED light projector that mimics the sun, a layer of materials using nanotechnology to do the same things to this light as the atmosphere does to sunlight, and an optical system to further enhance the perception of depth. In effect, we are recreating 10 kilometres of earth’s atmosphere in a layer of less than a metre.

Where did the inspiration come from?

About 15 years ago I was asked to give a talk to a primary school about light, and in preparation I bought a wonderful book called Light and Color in the Outdoors by an astronomer named Marcel Minnaert. In it he describes the physics behind outdoor lighting phenomena, ranging from the well-known such as rainbows, to the obscure such as a thin, bright line that can appear when the shadows of two tree branches overlap. He describes how light interacts with fog, with various types of clouds; the book contains more than 200 such observations.

I became fascinated with trying to capture these phenomena in my own photographs, and frustrated when I often couldn’t succeed. As a professor of optics, how was I not able to see these things? So I set about recreating them in my lab. And then a day came that changed my life. Having seen these effects in the lab, suddenly I started seeing them in the outdoors, and couldn’t understand how I’d been blind to them before. And it was not just nature I viewed differently: I started to see things in Renaissance art that I had previously not appreciated. I can only compare it to having been viewing the world in black and white, and suddenly seeing colour.

We developed an exhibition to demonstrate these effects, and thousands of visitors reported that they experienced the same sensation as I had – a feeling of having relearned the language of light, of reconnecting with the sky. At this point, in 2007, I started to think: what if we could take the techniques that went into this exhibition, and use them to create a product?

How did you fund the development of the technology?

Along with some of my students at Insubria University, in Como, Italy, we span off a company that enabled us to access European Union funds. In all, we received around €10 million from the EU, which enabled us to finance the development of the product to the point where private investors started coming on board.

Where do you see the skylight being used?

Interestingly, when we made a business plan, we researched the share of the lighting market across different areas – residential, office, hospitality, healthcare, transportation, and so on; and when we started showcasing the product and receiving enquiries, we found that the enquiries were coming pretty much exactly in direct proportion to the division of the market. This showed us that there is a desire for the product in every context where people need light.

The first market we are prioritizing is healthcare. In hospitals, some equipment needs to be in basements, perhaps because it is very heavy or produces radiation that needs to be shielded by protective walls. And for patients who are already unwell and feeling stressed about undergoing treatment, having to descend into a basement can add to the oppressive feeling. This is perhaps the situation where a sensation of natural light can be most beneficial.

There are many other contexts where it can be architecturally difficult to bring in natural light: office buildings, malls, airports, aeroplanes, underground trains, elevators, the spas and meeting rooms you find in the basements of hotels, and, of course, the basements of houses. As you would expect given the early stage of the product, it is still rather costly to produce, but we are committed to developing it in such a way that it becomes accessible for everyone, not only for the very rich.

Can it be retrofitted to existing properties, or is it more suited to being designed into new structures?

The first system we produced was rather big, requiring a metre of depth. But already we have managed to get our second system down to 65 centimetres, and we are working on a third system which will be around 50 centimetres, without compromising the quality of the effect. Then it becomes feasible to retrofit in any normal building with around 3 metres of vertical space to work with. What you lose in actual physical volume, you gain in perceived volume; if you are in a room with a CoeLux and a normal artificial light, switching to the artificial light makes the space feel much smaller.

And when you think about what architects could do when designing new buildings with this technology in mind, it opens up many new possibilities.

In terms of building deeper underground, for example?

It’s more profound than that. I believe architecture works when it gives us the sensation of being connected to the outside, because that is what makes us feel at home in the universe.

Think of how we humans evolved. We have a sense of comfort and confidence as we move through the world in daylight: we naturally perceive depth and distance in our surroundings, and we feel able to navigate our environment. In contrast, our evolutionary experience of artificial light – fire – came in contexts of huddling together for protection against threats that were lurking, unseen, in the darkness. In evolutionary contexts, too, being trapped in an enclosed space would have been a threatening experience as it would leave us vulnerable to predators.

So you would expect that the experience of being in an enclosed space lit by artificial light would be stressful, while the experience of feeling connected to the outside would be soothing.

Have any studies demonstrated this effect?

We performed a study with 200 people where we asked some to sit in a room with normal artificial light, and some in an identical room with a CoeLux skylight, and after an hour we tested for a range of psychological, physiological and biological parameters. The differences were unequivocal. People in the artificially-lit room had significantly raised levels of anxiety, for example, whereas those in the CoeLux room were completely normal.

I believe it is fundamental to our sense of connectedness to the universe that light entering our eyes feels like it comes from the sun. The fact that CoeLux is a ceiling fitting adds to the effect: we spend so much of our lives looking down, at our computer screens or whatever, while it is looking up that makes us feel connected to the universe. And it is wonderful to find that technology can give us that sensation in places where we would otherwise lack it – to find that an artificial sky can push the same soothing buttons in our brains as a view of the real sky.

That is what I hope CoeLux skylights will bring to the world: to help everybody remember that we are made for the infinite, for the sky.

Full details on all of the Technology Pioneers 2015 can be found here. 

Author: Professor Paolo di Trapani, founder and CEO, CoeLux

Image: A man walks past the ice encrusted woods in Earl Bales Park following an ice storm in Toronto, December 24, 2013. REUTERS/Gary Hershorn