Eli5: Why are nighvision goggles usually green?
In: 8
The goal of a night vision goggle is to capture and intensify light, typically the sheets that capture the light are made of phosphor, which has a Neat property that if electrons hit it, it starts glowing bright green… basically the light gets prepared through various filters and electrons then hit the sheet of phosphor.
Another thing is (we do Have other methods of doing it) but the reason why we use phosphor is fairly simple: humans can differentiate shades of green better.
This is also why you should put a cover on the night vision goggles in daytime and also why flashlights and flares and bright lights just are so intense on them.. the night vision goggles can very much over expose and “burn out” not too dissimilar to how an old photograph over exposes which is why old camera pictures get developed in dark rooms… they would just overexpose and get ruined instead.
The goal of a night vision goggle is to capture and intensify light, typically the sheets that capture the light are made of phosphor, which has a Neat property that if electrons hit it, it starts glowing bright green… basically the light gets prepared through various filters and electrons then hit the sheet of phosphor.
Another thing is (we do Have other methods of doing it) but the reason why we use phosphor is fairly simple: humans can differentiate shades of green better.
This is also why you should put a cover on the night vision goggles in daytime and also why flashlights and flares and bright lights just are so intense on them.. the night vision goggles can very much over expose and “burn out” not too dissimilar to how an old photograph over exposes which is why old camera pictures get developed in dark rooms… they would just overexpose and get ruined instead.
it’s a green phosphor screen at the back end of the goggles which glows green when electrons hit it. There are other variants like white phosphor and very rare red phosphor ones. The light enters the front lens which hits a photocathode which turns the light into electrons. Those electrons hit a microchannel plate which is a plate with millions of very tiny holes measuring a handful of microns across. The electrons do some magic bouncing off the sides of those holes it amplifies the electron output. Those electrons then run into the phosphor screen and turn into visible light.
it’s a green phosphor screen at the back end of the goggles which glows green when electrons hit it. There are other variants like white phosphor and very rare red phosphor ones. The light enters the front lens which hits a photocathode which turns the light into electrons. Those electrons hit a microchannel plate which is a plate with millions of very tiny holes measuring a handful of microns across. The electrons do some magic bouncing off the sides of those holes it amplifies the electron output. Those electrons then run into the phosphor screen and turn into visible light.
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