How Night Vision Works

The Night Vision Store & The OpticstoreDuring thegenerations that reflect the level of technology used.
history of warfare, operations at night have alwaysThe higher the generation, the more sophisticated the
been degraded significantly, if not totally avoided.night vision technology.Generation 0 - The earliest
Typically, soldiers fighting at night have had to resort to(1950's) night vision products were based on image
artificial illumination, e.g., at first fire and later with lightconversion, rather than intensification. They required a
sources such as searchlights. The use of light sourcessource of invisible infrared (IR) light mounted on or near
on the battlefield had the detrimental result of givingthe device to illuminate the target area.Generation 1 -
away tactical positions and information aboutThe "starlight scopes" of the 1960's (Vietnam Era)
maneuvers. The advent of new technologies initially inhave three image intensifier tubes connected in a
the 1950's and continuing into the present time hasseries. These systems are larger and heavier than
changed this situation. The engineers and scientists atGen 2 and Gen 3. The Gen 1 image is clear at the
the Night Vision & Electronic Sensors Directoratecenter but may be distorted around the edges.
(NVESD) have discovered ways to capture available(Low-cost Gen 1 imports are often mislabeled as a
electro-magnetic radiation outside that portion of thehigher generation.Generation 2 - The microchannel
spectrum visible to the human eye and haveplate (MCP) electron multiplier prompted Gen 2
developed equipment to enable the American soldierdevelopment in the 1970s. The "gain" provided by the
to fight as well at night as during the day in order toMCP eliminated the need for back-to-back tubes -
"Own the Night".Image Intensification: Image intensifiersthereby improving size and image quality. The MCP
capture ambient light and amplify it thousands of timesenabled development of hand held and helmet
by electronic means to display the battlefield to amounted goggles.Generation 3 - Two major
soldier via a phosphor display such as night visionadvancements characterized development of Gen 3 in
goggles. This ambient light comes from the stars, moonthe late 1970s and early 1980s: the gallium arsenide
or sky glow from distant manmade sources, such as(GaAs) photocathode and the ion-barrier film on the
cities. A soldier can conduct his combat missionsMCP. The GaAs photocathode enabled detection of
without any active illumination sources using only imageobjects at greater distances under much darker
intensifiers. The main advantages of image intensifiersconditions. The ion-barrier film increased the operational
as night vision devices are their small size, light weight,life of the tube from 2000 hours (Gen 2) to 10,000
low power requirements and low cost. These(Gen 3), as demonstrated by actual testing and not
attributes have enabled image intensifier goggles forextrapolation.Thermal Imaging:Most objects in natural
head-worn, individual soldier applications and resulted inscenes, as well as human beings and manmade
hundreds of thousands of night vision goggles to beobjects emit electro-magnetic radiation in the form of
procured by the US Army. Research andheat. Thermal imagers or infrared viewers (also known
development continues today on image intensifiers inas FLIRs) gather the infrared radiation and form an
the areas of longer wavelength spectral response,electronic image for the soldier. Since they do not rely
higher sensitivity, larger fields of view, increasedon reflected ambient light, thermal imagers are totally
resolution, advanced displays and image fusion.Nightlight-level independent. They also have significant
Vision technology consists of two major types: imagepenetration capabilities through obscurants such as
intensification (light amplification) and thermal imagingfogs, hazes, and conventional battlefield smokes. There
(infrared). Most consumer night vision products are lightare two varieties of thermal imaging systems: cooled
amplifying devices.Light amplification technology takesand uncooled. Cooled thermal imaging requires
the small amount of light, such as moonlight or starlight,cryogenic cooling. Lower performing uncooled thermal
that is in the surrounding area, and converts the lightimaging systems require no detector cooling but have
energy (scientists call it photons), into electrical energysufficient performance to provide the low to medium
(electrons). These electrons pass through a thin diskperformance required by individual soldier sights,
that's about the size of a quarter and contains over 10infantry vehicles, navigation, robotics and missile
million channels. As the electrons travel through andseekers. Present research and development in cooled
strike the walls of the channels, thousands morethermal imaging are pursuing multi-spectral imaging,
electrons are released. These multiplied electrons thenimproved sensitivity and resolution, and embedded
bounce off of a phosphor screen which converts thesignal processing to aid the soldier in target acquisition
electrons back into photons and let you see anmissions. Current uncooled research is directed at
impressive nighttime view even when it's really dark. Allsmaller size packages and power consumption with
image intensified night vision products on the marketlower cost and increased sensitivity, resolution and field
today have one thing in common: they produce aof view. Small, palm-sized uncooled thermal imagers
green output image. In the night vision world there areare now available.