Introduction to UV-C lighting

Ultraviolet light is a range of wavelengths just below the visible light range. It is divided into three different bands, with UV-C starting from 200 nm and going all the way up to 280 nm. As the DNA and RNA of most bacteria and viruses are most sensitive to radiation between 260−270 nm, (germicidal effectiveness goes up to 310 nm) UV-C light is capable of killing them, acting as a contactless, chemical-free disinfectant. Although it is not always necessary to kill all pathogens, UV-C light can be used to simply prevent them from replicating. This achieves the same germicidal effectiveness at significantly lower levels of UV exposure, which is good for materials and reduces luminaire costs, etc. HEALTH WARNING: UV-C is a high energy form of radiation, exposure to which is a possible health risk to humans and can also harm some materials. High dosages of UV-C can lead to serious burns, skin cancer etc. Very short UV wavelengths also produce ozone and can be considered a health risk at higher concentrations. As UV-C light is completely invisible to the human eye, it is good practice to incorporate some visible light LEDs such as blue to indicate your light source is turned on.

Traditionally UV-C is produced by mercury lamps that need replacing up to ten times within the lifespan of UV LEDs. Because of their longer lifetime, UV-C LEDs are a viable option compared to mercury lamps and also offer an easily controllable light source. LEDs make it is easy to optimize and adjust the required exposures and also allow the use of secondary LED optics. UV LEDs are also getting cheaper, further increasing the advantage of using them.