Even if formally released by Nichia to announce the effectiveness of 405nm for sterilization purpose as well as to be human friendly as a general lighting source, most people still believe that only UVC is the way out, and don't believe this technology, which has actually been within GE Lighting's product porfolio more than 10 years.
Bacteria are killed when exposed to the sunlight for a long time. This is called sunlight disinfection. This phenomenon is caused by the reaction of the organic compound called porphyrins in bacteria and sunlight. Porphyrins absorb light around the wavelength of 405 nm and produce reactive oxygen species (ROS). When ROS is accumulated in bacteria, they oxidize and destroy cell membrane. 405nm is environment friendly and safe because it works in the same way as sunlight disinfection.
The pioneers in sterilization lighting area have actually developed and lauched a series of commercial or industrial grade 405nm disinfection fixtures as well UVC germicidal lighting products.
Upon the rich R&D projects experience with GE upon 405nm technology, Ken's team has successfully promoted their 405nm disinfection downlight to the Japanese market to be installed in the McDonald shops, and what's more, formally broadcast by the local TV program.