Therefore, UV-C LED lighting has become popular, and companies are investing resources in designing UV-C LED luminaires for use in hotels, trains, and hospitals. Other companies are working to add UV-C LED light to existing products to disinfect frequently touched surfaces, such as ATMs. This technical document discusses LED lighting, UV-C sterilization LED light, and MEAN WELL LED drivers suitable for UV-C LED lighting.
Figure 2: Scattered wavelengths of the lighting LED
UV-C Sterilization LED Light:
UV-C sterilization LED light has two important parameters for disinfecting a surface: distance and time. A single UV-C LED of approximately 2.5W can emit 99.9% irradiance on a 6cm surface, as illustrated in Figure 3. Irradiance is the amount of energy flux or brightness on a surface. In other words, it can sterilize 99.9% of germs on a 6cm surface. However, when the surface is slightly farther away, such as 10cm, the sterilization rate drops to 25%. To increase the sterilization rate, more time is required.
Figures 3 and 4: UV-C LED irradiance versus distance
The curve in Figure 2 shows the distance versus time required to sterilize a surface by approximately 99.9%, with approximately 5 minutes needed for 45 cm and approximately 18 minutes for 100 cm. Therefore, time and distance are critical parameters for UV-C LED sterilization. Furthermore, these lights are often designed with programmed on/off controls to sterilize a surface in cycles, such as 15 or 30 minutes per cycle. Distance, time, and on/off control are directly related to selecting an appropriate LED driver for the UV-C LEDs. Table 1 shows the required LED driver output power for a UV-C LED sterilization light to sterilize a surface area of 45–60 cm and 180–420 cm. For example, a 20W LED driver can be used to power an 18W UV-C LED array to sterilize 99.9% of germs on a 45-60cm surface in approximately 5 minutes. The LED driver with dimming capability allows you to program the light to turn on/off for the sterilization cycle. Similar to a lighting LED, it can be driven by a constant current or a constant voltage LED driver, where the former directly drives the UV-C LED and the latter indirectly via a built-in DC/DC step-down LED driver.
In summary, UV-C sterilization LEDs have a wavelength of approximately 275nm and can be driven by either constant current or constant voltage LED drivers. They sterilize surfaces in cycles, utilizing a dimming function to turn the LED driver off. To shorten the sterilization time for a given distance, a higher-power LED driver is required. Table 1 lists MEAN WELL LED driver models with a dimming function that are suitable for UV-C sterilization LEDs for surfaces at distances of 45-60cm and 180-420cm. Additionally, higher power ratings in the XLG-100/150/200/240 series are also available for 360-degree UV-C sterilization LEDs.
