Recent advancements in lamp technology have led to a competitive and more environmentally friendly market. The more traditional light sources of incandescent and fluorescent lamps have come under pressure due to recent technological developments.

Incandescent lamps are inefficient, giving efficiencies of typically only 20 lumens per watt while their fluorescent counterparts, despite giving good efficiency, have always posed a health risk because of their mercury content.

Mercury is a poisonous metal that is not dangerous whilst surrounded by glass and operating in a lamp, has been known to affect the nervous system adversely after prolonged exposure to a significant amount. Lamps use only minute amounts of mercury which cannot escape into the environment unless the glass is damaged. But this does lead to issues with safe disposal.

It is this health risk that has led to changes in European law in recent years requesting a reduction in the levels of Mercury being used in these lamps and encouraging manufacturers and research laboratories to continue to look at even more alternative sources of lighting. The LED lamp revolution has seen a reduction in the use of both of these traditional lighting sources.

LED lamps are mercury free and very efficient, giving anywhere between 50-100 Lumens per watt while their lamp life also gives them an advantage over their predecessors.

In addition to LED lamps there is now a new safe, efficient and exciting mercury free alternative ready to hit the market, one that could revive the fluorescent lamp industry.

In October 2013 in Hannover, Germany, the Karlsruhe Institute of Technology unveiled the latest market lighting solution, a mercury-free fluorescent lamp; a lamp which works with the aid of microwave technology.

The team at the Karlsruhe Institute of Technology, led by Professor Rainer Kling have been working for the last two years to create a mercury free lamp. In autumn they presented their prototype to much acclaim at the Hannover Fair and the lamps are now set to go into production in late 2014/2015.

Willie Duggan Lighting caught up with Celal Mohan Ögün from the ECG- and Plasma Technologies department in Karlsruhe Institute of Technology to learn more about mercury-free fluorescent lamps and what impact they can make on a competitive market.

How did you go about developing a mercury free lamp? We, the Light Technology Institute of the Karlsruhe Institute of Technology, have been developing novel and efficient light sources and their electronic control gears for years. In the last two decades, our research was focused on electrode less and mercury free UV-light sources, like excimer lamps, which are only filled with noble gases. A couple of years ago, the European Union declared a so called “Restriction of Hazardous Substances Directive” and restricted the amount of mercury inside the lamps. Also the Federal Institute for Occupational Safety and Health of Germany has restricted the allowed concentration of mercury with the directive TRGS 900. With both directives at hand, we began to investigate possible mercury substitutes for general lighting applications.

What is the difference between LED bulbs and your mercury free bulbs? LED bulbs show very good efficiency at low wattages, but at higher light than 15 W, the cooling of the LED gets harder and the cooling problem effects also the efficiency and the light quality of the LED. In addition to that, all general lighting LEDs emit blue light and this blue radiation is shifted to other visible wavelengths with a standard phosphor coating. The colour temperature can only be changed with the coating thickness and the colour rendering index (CRI) is also not that high. With our mercury free lamp, a higher CRI can be achieved.

How has the new product been received so far? Well, we are only a research institute and not a commercial lamp manufacturer. Therefore, we don’t call the mercury free lamp a product but only a new technology we developed. Back to the question: We also showcased our technology in the international Light & Building Fair 2012 in Frankfurt, as well as at the Hannover in October 2013. Both times, the interest in our technology was great. We could sell a lot of lamps, if we had more than some prototypes. But as I said, we are only a research institute.

How can you achieve increased wattage in the bulbs? Our lamp is electrode less. That means, the applied power is not limited because of current and voltage characteristic of the electrodes, instead, we use high frequency electromagnetic waves to apply power into the lamp. A novel high frequency coupler and plasma launcher were developed by our project partner, the University of Applied Sciences Aachen with an integrated electronic control gear for the generation of HF-power. We don’t have any limitation for the lamp geometry (diameter or length of the lamp bulb) or applied power. Of course, there is always an optimal operation point for every geometry, which you have to consider for an efficient operation, but by variation of the lamp parameters, it is also possible to move the optimal operation point to higher powers.

What’s the efficiency of the lamps? This technology was developed to substitute compact fluorescent lamps with mercury. Our lamp has about the same efficiency with the CFL ~ 55 lm/W. The efficiency of the transistors in the electronic control gear limits the general efficiency but thanks to the mobile phone industry for financing the research for high frequency transistors very strongly, the general efficiency of the lamp increases every day and the costs are sinking.

This is certainly an exciting development in lamp technology, one we think could ensure the survival of the florescent lamp in what is a competitive market place. While the technology is currently at the development stage, Dr. Franz-Josef Bierbrauer, general manager of 3PP Bulb, who will manufacturer the mercury free bulb, has revealed that they are currently in talks with industrial partners with a view to getting this exciting new product on the market by 2015.

Here at Willie Duggan Lighting, we welcome the innovation and changes that the lamp industry is going through and we can’t wait to have another light source to help us in our creation of original designs!!!