Night vision devices with IR illumination

 

— the built-in IR illuminator provides illumination of the observed scene with IR radiation, which is invisible to the naked eye, but is well perceived by the NVD receiver. This option makes it easier to work with the device in situations where light and IR radiation is too low even for specialized devices — for example, in dark rooms with no windows at low temperatures. It is worth noting that some emitters can be seen in the visible range; see "invisible radiation spectrum" for details.