Many people associate ultraviolet (UV) light with an unpleasant sunburn. But this short-wave radiation has the capacity to solve important problems of the future.
Ultraviolet radiation – we cannot see it and we cannot smell it. Yet it is all around us, always active. The germicidal effect of this “blue light” was discovered by doctors back at the beginning of the 20th century. Today it is used for purifying water, disinfecting air conditioning systems and for curing plastics. But classic UV light sources contain mercury and have a limited lifespan. Time therefore for a new solution.
This is where modern LED technology comes to the rescue – and is more than just a replacement for existing UV light sources. LEDs are robust and emit radiation only in a very narrow energy band. This can be tailored specifically for chemical and biological processes, opening up entirely new areas of application.
“In one or two years’ time UV LEDs will be genuine commercial alternatives. Now is therefore the time to develop the market for integrated LED solutions,” says Nico Morgenbrod, Business Development Manager at OSRAM. From his base at the Berlin Spandau plant he is currently visiting potential customers to gain a better understanding of their needs and applications. And to build up partner networks.
On the home straight
On the other side of the capital, in the eastern district of Treptow-Köpenick, is the Ferdinand Braun Institute, Leibniz Institute for High-Frequency Technology, where Professor Günther Tränkle is pressing on with the development of high-power UV LEDs. As the director of the research institute, he is convinced of the potential of UV LED technology: “LEDs are compact, cold light sources. They have long lifetimes even under high loads and mobile use.”
In terms of efficiency and competitiveness, however, the end is not quite yet in sight. Development work is technically very challenging. The shorter the wavelength of the light, the more difficult it is to produce LEDs. It needs plenty of experience and highly specialized know-how. OSRAM Opto Semiconductors brings both to the “UV power” project of the national “Advanced UV for Life” (AUVL) consortium which is being coordinated by the Ferdinand Braun Institute.
Light instead of chemicals
At the OSRAM site in Regensburg, Hans-Jürgen Lugauer directs the development of the high-power chip for the 270 to 290 nanometer wavelength range: “UV LEDs with this spectrum are used for disinfecting water, air and surfaces without the need for chemicals. We are focusing on developing these very high-power and extremely durable components for mass production.”
Initial industrial pilot applications with UV LEDs, such as for curing plastics, are already in use. The members of the AUVL consortium are also exploring applications in medicine, such as effective disinfection strategies to combat multi-resistant bacteria and phototherapy treatments for skin disorders. Other areas of research include the targeted control of plant metabolism to enrich specific substances, and industrial curing processes. “Small LEDs offer great leverage,” is how Tränkle summarizes the wide-ranging potential. Of particular interest is the integration of UV LEDs precisely where they are needed – for example directly in a water tap or water dispenser.
Clean water throughout the world
Providing clean water has enormous potential for the future. Clean water and clean air are becoming more and more valuable by the day. And not only in private households – in industrial enterprises there is an urgent need for sustainable solutions for clean, processed water. Water purification is already possible with conventional technologies but not with the necessary durability, not for high loads and not in application-specific wavelengths.
From supplying light to understanding customers
“It is crucial to have a precise understanding of the customer’s application,” explains Morgenbrod. “Up to now, OSRAM has been involved in visible light. We have provided plenty of that in plenty of places. Today, customers are asking us how many germs per cubic meter of water can our UV LED solution render harmless,” adds Morgenbrod, highlighting the transition of OSRAM from a lighting provider to a photonics specialist and from a hardware supplier to a solution provider. Potential customers are mainly plant manufacturers and system providers in the fields of water, hygiene and food technology.
For water treatment they need the right radiation at the right place in the right amount. UV LEDs not only make this possible for large volumes but also save energy. The basic work has been completed. Morgenbrod is convinced that “for many applications the days of the mercury lamp are numbered. Now we are working on commercialization. And on what our customers need most of all, namely individual plug-and-play solutions for industrial water treatment.”