Night
vison devices are a type of eye-wear that allows one
to see in the dark. They are most often used by the
military.
Night vision devices are one of two types. One type
of night vision device picks up any light in the
given area and amplifies it several thousand times.
This type is commonly used for war reporting, tinting
the picture green. The color green is chosen because
the human eye is most sensitive and able to discern
the most shades in that color. The other common type
of night vision device are heat-sensing/infrared
devices. These show anything that emits normal heat
radiation in the given area.
There are currently devices that combine both of
these technologies to create images that are almost
as clear as day. In addition to devices such as night
vision goggles, night vision technology is also used
in rifle scopes,
security
cameras, binoculars, etc.
Night vision devices work by the photo-electric
effect. As a photon collides with a detector plate,
multiple electrons are ejected from the metal that
are then amplified by a series of electron ejections
onto a phosphorus screen. The colour green is selected
as it is the optimum luminosity for the human eye
during night time.
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