Visible light has certain properties depending on the wavelength at which it is emitted. There is enough literature and research available on this. Some of the relatively recent scientific research, studies and clinical trials (spanning more than a decade) have established that visible light of a specific narrow band wavelength can also be used for disinfection. This is with the additional benefit that it can be used for lighting as well, in presence of people without any harmful effects. Ref. research paper was published in Glasgow, US on Sep 30,2010 wide pub. No US 2010/0246169 A1.