How do NVD's work?
Night visions let you see in the dark!
So there is a small amount of light (photons) which went trough the lens of the objective. After the photons are entering the lens there will got trough a photocatode in the image intensifier tube (IIT) which converts the photons into electrons.
After that the electrons went trough the MCP ( Micro channel plate). This Part of the night vision tube does what the name is saying... it multiplies the electrons what results in a much stronger electron-signal what amplifying the image what we can see. After the huge amount of electrons went into the phosphor screen at the end of the image intensifier tube (IIT) there will be converted into photons! After all this processes we are able to see the typical green or white image with our eyes when we look into a night vision device.