you don’t need safety glasses as UVC does not penetrate all the way to the retina, but anything like skin gets a terrible time being sterilized
good UVC LED like Klaran 50mW costs about 20$ in quantity naybe 10$, then 20$ for the quartz glass window, likely they use a plastic aluminum coated reflector
so looking just on LED and optics we hit 200$
If they go cheap with 3-5mW LEDs there is no purpose using 18 of them if 2 Klaran can do the same output
below 300nm you need quartz glass (fused silica) borosilicate will block UVC
Ask Schott how much B2O3 it contains, it has to be a glass that has almost none in it or it would block UV
such glass composition is called quartz not borosilicate
I would like to know how light sterilizers kill the germs hidden in cracks and crevices.
Seriously.
Seems like they are marginally OK for countertops.
Food, no, clothes, no, skin, no,
mouth/nose - double no, plus harmful
plus even if there are no cracks etc, how do you know you are exposing the right amount to kill the bad germies - on every square mm?
seems like clorox would work better
plus not blind or sun burn you.