What do the Japanese learn from the Czechs? Would you believe that developing lighting fixtures can be an adrenaline sport? Has Europe fallen behind with LEDs? How do winter doldrums help in the development of dental luminaires? Read the interview with Ing. Antonín Fuksa, lead developer of DentaSun luminaires at NASLI and lead designer of the full-spectrum lighting studio.

How did you get into full-spectrum lighting?

I was solving a problem with the lighting of colour slides. The yellows, purples and deep reds looked completely different in fluorescent light than in daylight. I tried different fluorescents with excellent color rendition, but it still wasn't right. Eventually, I obtained some samples of the then new NASLI brand of fluorescents, which proved to be extremely suitable for my purpose and the colours were a joy. The NASLI boss and I hit it off right away. He approached the same problem from the opposite side, when he couldn't get fluorescents that would last long into the night in the office without burning his eyes, he had them made.

I then worked for NASLI externally for a few years and I enjoyed the light more and more. Eventually I left my previous job to pursue light full time. Gradually, we built a facility for developing and modifying luminaires and a laboratory for measuring the properties of light sources, and started a lighting studio for full-spectrum lighting design.

What about the dental lights?

The DentaSun product line with NASLI fluorescent lamps was established in 2009. A year later we started to improve the luminaires, they gained more power, a new slimmer shape, lost some weight and added the possibility of dimming and remote control. However, the compact layout brought new challenges in terms of suppression, so I had to use all the existing knowledge in the development and still learn something new to make the result to our liking.

How does such a development of luminaires actually take place?

The key is to listen. Find out what the customer needs and what requirements the lighting must meet. Everything is then handled by our team in terms of design, construction and production. The result is a prototype luminaire that has all the required parameters (light characteristics, dimensions, number of lamps, optical systems, controls) and meets the electrical safety requirements. We then order the rental of an electromagnetic compatibility laboratory in an accredited testing facility. This has the advantage that I am present during the measurements and can promptly suggest and make adjustments to the luminaire if the interference exceeds our company limits or even legal limits. Dimmable luminaires with control electronics are the most difficult. We are sticklers for interference and our requirements often go beyond the standards. There is also time for experimentation, which I sometimes use to cover my curiosity. After all, lab services are quite expensive. I usually test more complex luminaires in multiple rounds, leaving the test lab with a bug in my head about how to reduce interference. The feeling that I don't know HOW at the moment, but it's clear to me that I WILL solve it, is one of the best things about this job. We then order the sample, thus modified and "filtered", for full tests to verify everything. In the meantime, the technical preparations for production are already underway.

Where do you manufacture the luminaires?

NASLI ceiling and wall lights are manufactured in the Czech Republic. Thanks to this, we have supervision over the design and quality already during production. We are always inventing something new, so development and production must be perfectly linked to make everything work as it should. We keep this a bit under wraps...

Do you also cooperate with foreign companies?

They manufacture table lamps for us in China and Japan. As far as LEDs are concerned, in Europe a lot of companies are still waiting, and in China they have gained years of experience so far. I was surprised at how nice and high-quality they can make things. For traditional lamp manufacturers, the electronics around LEDs bring a potential source of electromagnetic interference that they have not encountered before. This was evident not only in the nice Chinese lamps, but also in the designer lamps from a traditional Japanese manufacturer. For both companies we designed and tested a suppression system that meets the standard requirements by a wide margin. It makes me feel good that not only do we learn from them, but they learn from us. Especially with the Japanese, I really appreciate the mutual respect. During my visit, I was offered a job in a development laboratory with state-of-the-art equipment by several large Chinese companies. That makes you happy, even if you don't accept the offer. But I suspect one or two companies were just trying to distract me.

You are dealing with the non-visual effects of light. How does it work?

In 2007, light-sensitive ganglion cells were confirmed in the human retina, which respond to a certain amount of light. Their signal does not go to the visual cortex in the brain, but to the central clock. Light thus controls our daily rhythm and sets the beginning of our physical and indeed social daily cycles. Chronobiologists still emphasize the benefit of the regularity of these rhythms. But how can we achieve this regularity when, around Christmas, the sun rises at 8 a.m. and sets at 4 p.m.? Many people suffer from seasonal mood disorders in autumn and winter or become more depressed. Properly timed lighting of the right intensity can help a lot with this. According to one study, light therapy can be fully compared to the effects of depression medication. Cool light works best early in the morning, perhaps before sunrise, when one gets a kind of biological boost, a kick-start to the day. During the day, such light helps maintain alertness and focus. But don't shine it in the evening, or you won't sleep.

Do you make any products based on this principle?

Yes, all NASLI light sources have a high content of this activating ingredient. Compared to incandescent light of the same intensity, they contain three times more of it. Such light is cooler, but in combination with the high quality of colour rendering, especially the deep reds, it looks very natural. People work and communicate well in such natural light. The best light is, of course, sunlight and we try to get just a little bit closer to it.

We take care with our luminaires to maintain these qualities of light. Last year, we did a pilot project for the psychiatric clinic of the VFN, intensive adjustable lighting in a room and lounge. Not only the patients, but also the staff liked these rooms very much and go there to "recharge". This year we won the tender for the luminaires above the bed. This already has elements of biodynamic lighting, it can vary not only the intensity but also the tone of the light over a wide range, and so it is again a little closer to what is happening in the sky, from the first rays at sunrise to the intense midday "fire". The lighting is controlled according to a timetable that can be programmed at will. For example, you can set a light cycle like May Day and use it throughout the winter. Different therapeutic programmes can also be set. According to studies, this is very helpful for long-term patients. There's still a lot to explore. With every new product we come up with something new to improve on existing fixtures. With the development of the solar simulator against winter depression, for example, we have improved the design of luminaires for dental surgeries.

What kind of education do you have?

I studied measurement and instrumentation technology at the Faculty of Electrical Engineering, Czech Technical University in Prague. Knowledge about measurement of all possible quantities, construction of instruments, electromagnetic compatibility or programming is a good basis, but I had to study a lot of information, most of it on the job. I spend a lot of time studying research articles, not only technical but also medical, on the effects of light on humans. Lighting design is an art in addition to a technical discipline, where I have to choose one solution out of many that fits the feeling. Often it is not a solution that looks nice on paper. I guess this is hard to get other than through experience. I have the round stamp of a CKAIT authorized engineer for the field of building environment technology, specializing in electrical equipment, of which I work almost exclusively with lighting. I have published several articles on non-visual effects and light quality in the professional journal Light and a free series on light in dental offices in your magazine.

How do you see the future of lighting?

LEDs will definitely play a major role in it. Manufacturers today are competing mainly in efficiency. I expect that once the "physical barrier" of efficiency is reached, the quality of colour rendering will come to the fore. After all, even today LEDs with nice colour rendering are more affordable than a few years ago. But one has to choose well and ask for parameters so that the light meets all requirements. I think that some traditional light sources will die out completely, whether at the hands of the market or legislators, but fluorescent lamps will keep their place in the world. I suspect there will be increasing pressure to save energy, whatever the cost. On the other hand, it will help lighting control applications, which have aesthetic and ergonomic benefits in addition to savings. Variable lighting can not only improve people's work performance but also their mood and bring a dynamic visual element to a space. Standardisation in the LED field, where manufacturers so far consider the unmistakability of their modules to be an advantage, will probably also help a lot. Wireless lighting control is also likely to penetrate not only the workplace but also the home. So we still have a lot to invent and we like to push the boundaries not only in less explored areas of lighting technology.

Author: PR, DentaSun
Published in StomaTeam magazine