Efficiency Leap for UV-C LEDs "We focus on a Wavelength of 265 Nanometers"

Related Vendors

FAULHABER Drive Systems

Taiwan Machine Tool & Accessory Builders' Association (TMBA)

The EU exemption for mercury-containing UV-C lamps is shaky. This makes a technology switch to LEDs unavoidable. In this interview, Alexander Wilm from AMS Osram explains how the balancing act between maximum disinfection effect and high LED efficiency can be achieved.

UV-C radiation is a proven means of disinfecting water, air and surfaces. Until now, classic low-pressure discharge lamps have dominated here. Their big problem: they contain toxic mercury. The current EU exemption (RoHS) for these lamps expires on February 24, 2027. Whether and to what extent it will be extended is currently the subject of heated industry discussions.

The industry is desperately looking for sustainable, mercury-free alternatives. Until now, the widespread use of UV-C LEDs has often failed due to their relatively low efficiency, particularly at the wavelengths that are ideal for disinfection, as well as their service life. However, AMS Osram has reported a technological breakthrough that is set to significantly reduce the gap between UV-C LEDs and conventional tubes. In this interview, Alexander Wilm, Senior Principal Engineer and Key Expert Light & Life at AMS Osram, explains where the technology currently stands.

Mr. Wilm, which UV-C wavelengths does AMS Osram use for UV-C and why? What is the compromise between disinfection effect and LED efficiency?

We focus our UV-C LED portfolio specifically on the wavelengths 265 and 275 nm, with a clear emphasis on 265 nm and thus on the maximum germicidal (germicidal, editor's note) efficacy. This wavelength is close to the maximum absorption of DNA and RNA and therefore enables the highest inactivation rate of microorganisms.

At the same time, 265 nm places the highest demands on LED technology due to the shorter wavelength. We are therefore continuously working on key technological components such as epitaxy, chip and package design in order to further increase efficiency in this particularly demanding spectral range. The aim is to reconcile maximum disinfection effect with ever greater efficiency without compromising on reliability and service life. In this way, we want to close the gap to classic lamp technology while at the same time significantly increasing system flexibility.

How high is the current efficiency of the UV-C LEDs you offer, and where is the limit compared to classic UV-C low-pressure lamps?

Last year, we succeeded in achieving a technological breakthrough. The achievable efficiency of our new UV-C LEDs is over 10 percent with an output of 200 mW, a wavelength of 265 nm and a service life of more than 20,000 hours. This is a significant improvement on previous generations, whose efficiency of 5.3 percent was only around half as high.

Classic UV-C low-pressure lamps with typical efficiencies of 30 to 40 percent are of course still superior at the moment. However, LED technology offers additional systemic advantages such as compactness, switchability and freedom from mercury, meaning that it is becoming increasingly important in many applications despite its lower efficiency. Our combination of increased efficiency and a proven service life of more than 20,000 hours represents an important technological milestone.

Is that enough to cushion the impact of the impending mercury ban?

With these specifications, LEDs already have the potential to replace conventional discharge lamps containing mercury in selected applications. Mercury is always a risk during production, operation and disposal and poses risks to health and the environment. The need for more sustainable alternatives such as UV-C LEDs is becoming ever greater in light of the EU exemption that expires in 2027. Our teams are working flat out to develop and refine the new UV-C LEDs. They are due to be launched on the market at the beginning of next year.

However, one physical property remains: UV-C LEDs generate a lot of waste heat, which can affect their service life. What requirements do you place on the thermal design in the application?

At application level, we recommend a holistic thermal concept that takes into account the PCB layout, the heat sink and, depending on the application, active cooling measures. Efficient heat dissipation means that the high efficiency can be utilized permanently and the proven service life of more than 20,000 hours in real operation can be ensured. (heh)

Secure Access Management

A Unified Approach to Physical Access