Development of Mercury-Free Far-UVC Light Source Using Luminous Array Film Technology and Its Germicidal Effects

Far-UVC has emerged as a promising alternative for ultraviolet germicidal irradiation (UVGI). We developed a novel far-UVC light source using Luminous Array Film (LAFi), which excites phosphors by plasma discharge in a neon–xenon gas mixture within a glass tube. An optimal phosphor composition was determined, comprising aluminum phosphate, lutetium phosphate, and scandium. The plasma light module (PLM228) emits far-UVC radiation with a peak wavelength of 228 nm. Improvements in emission intensity and ozone generation suppression were achieved by modifying the glass materials. Escherichia coli, methicillin-resistant and methicillin-sensitive Staphylococcus aureus, and influenza A virus were inactivated by approximately 99.9% (−3 log<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub>) upon exposure to 3 mJ/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> irradiation using PLM228. The bactericidal and virucidal effects of PLM228 surpassed those of other UV and far-UVC devices. PLM228 demonstrates significant potential as a mercury-free alternative UV germicidal light source.