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An image intensifier is the component of a night vision device that amplifies visible and near-infrared light from an image so that a dimly lit scene can be viewed by a camera or by eye. Unlike a thermographic camera, an image intensifier does not work in the total absence of visible (or near infra-red) light. It does, however, create a more realistic image, because the intensities it shows are related to true optical intensity and not to temperature. This realism makes it more suitable for use by untrained operators and can be used to view objects not visible by a difference in temperature alone. Image intensifiers are also much less expensive than thermal imaging. Wikipedia does not have an article with this exact name. ... An American soldier uses a helmet mounted night vision device A night vision device (NVD) is an optical instrument that allows images to be produced in levels of light approaching total darkness. ... An American soldier uses a helmet mounted night vision device A night vision device (NVD) is an optical instrument that allows images to be produced in levels of light approaching total darkness. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... This article does not cite any references or sources. ... Large format camera lens. ... A human eye Eyes are organs of vision that detect light. ... Image of a small dog taken in mid-infrared (thermal) light (false-color). ... In physics, intensity is a measure of the time-averaged energy flux. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ...

Image intensifiers were invented by Vladimir Zworykin, an employee of U.S. company RCA during World War II. His work and creation of the first generation 0 device became the basis for the sniperscope and snooperscope. Parallel development in Germany occurred by AEG in 1936, producing a prototype for the Pak anti-tank gun in 1939, which were later mounted on panzer tanks, and the "Vampir" man-portable system for infantry with MP44 rifles. Vladimir Zworykin, 1929, holding his kinescope Vladimir Kozmich Zworykin (Russian: ) (July 30, 1889 - July 29, 1982) was a Russian-American inventor, engineer, and pioneer of television technology. ... RCA, formerly an acronym for the Radio Corporation of America, is now a trademark owned by Thomson SA through RCA Trademark Management S.A., a company owned by Thomson. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... AEG volt-meter designed by Peter Behrens AEG (Allgemeine Elektrizitäts-Gesellschaft, General Electricity Company) was a German producer of electronics and electrical equipment. ... 1936 (MCMXXXVI) was a leap year starting on Wednesday (link will take you to calendar). ... Year 1939 (MCMXXXIX) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar. ... Panzer IV Ausf. ...

How it works

Image intensifiers work by having an objective lens focusing an image into a vacuum tube with a photocathode at one end that releases electrons by the photoelectric effect on the incidence of incoming photons. From there, the photoelectron is accelerated through around 5000 volts into a tilted microchannel plate. The high energy electron releases some microchannel plate electrons, which further release other electrons, in a process called secondary cascaded emission. The MCP is tilted to encourage more electron collisions, thus increasing the rate of emission of secondary electrons. Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... In an electron tube, a negatively charged electrode coated with a photosensitive compound. ... e- redirects here. ... A diagram illustrating the emission of electrons from a metal plate, requiring energy gained from an incoming photon to be more than the work function of the material. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... A microchannel plate detector is a type of detector used in mass spectrometry which is closely related to an electron multiplier. ... A microchannel plate detector is a type of detector used in mass spectrometry which is closely related to an electron multiplier. ...

The electrons all move together due to the potential difference across the tube, and where one or two electrons entered, thousands may emerge. A separate (lower) charge differential in the tube accelerates the secondary electrons until they hit a phosphor screen at the other end, releasing a photon for every electron. Provided the electric field is uniform, the electrons have a linear path, so correspond to the exact incident image. The image is focused by conventional optics using an ocular lens. The only multiplicative stage is in the secondary cascaded emission. The phosphor is usually green, as the human eye is more sensitive to green than other colors (hence the soldiers' nickname 'green TV' for image intensification devices). Image File history File links Size of this preview: 800 × 431 pixelsFull resolution (852 × 459 pixel, file size: 67 KB, MIME type: image/jpeg) Made myself. ... Image File history File links Size of this preview: 800 × 431 pixelsFull resolution (852 × 459 pixel, file size: 67 KB, MIME type: image/jpeg) Made myself. ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ... Leafy green fountain in Wattens, Austria. ...

Generation 0

The first application for night vision was for American snipers in World War II^{[citation needed]} . Nicknamed the "sniperscope" and "snooperscope", they were designated the M1 and M3 infrared night sighting devices. They are simple devices that do not produce a net amplification of light, but rather allow a user to see near-infrared light. Along with beam filters, this allowed snipers to illuminate their target without their target being aware of it. However, night vision became employed by both sides, and as a result the "active" IR beams began to betray the sniper's position. Arkansas Army National Guard soldiers practice sniper marksmanship at their firing range near Baghdad, Iraq in 2005. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ...

Generation 0 devices took a lot of power to use, for both the tube and the IR illuminator, had a very distorted picture due to a cone-shaped electrode design, and a short tube life due to the high electrical voltage. Generation 0 featured a photocathode made of a mixture of silver, caesium, and oxygen called S-1 which provided approximately 60 mA/lm sensitivity to light. General Name, Symbol, Number silver, Ag, 47 Chemical series transition metals Group, Period, Block 11, 5, d Appearance lustrous white metal Standard atomic weight 107. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...

Generation 1

Generation 1 devices are also called "Starlight scopes", and were a tremendous improvement upon generation 0. They are much more power efficient, amplify light better, and produced a superior image. These devices were initially used in the Vietnam War, but were unable to function well without moonlight until heavy and bulky 3-stage tubes were deployed. Generation 1 also used a different photocathode, S-20, which provided about three times the photo sensitivity of Generation 0. Combatants Republic of Vietnam United States Republic of Korea Thailand Australia New Zealand The Philippines National Front for the Liberation of South Vietnam Democratic Republic of Vietnam People’s Republic of China Democratic Peoples Republic of Korea Strength US 1,000,000 South Korea 300,000 Australia 48,000... Moonlight has several meanings: Moonlight is the light that is perceived as coming from the moon. ...

However, generation 1 devices still have a relatively short tube life, and a single stage device does not amplify light much better than a dark-adjusted eye unless multiple stages are used. They still carry the benefit of being able to use a somewhat "invisible" IR illuminator, though.

Generation 1 remains one of the most popular types of night vision today. Despite its poor performance, its low cost entices people who are looking to pick up night vision as a toy.

Generation 2

Generation 2 was a major technological breakthrough. Although the photocathode material, S-25, wasn't much of an improvement over Generation 1's S-20, generation 2 devices introduced the microchannel plate (MCP, see: Micro-channel plate). The microchannel plate consists of a bundle of thousands of tiny glass fibres fused together in parallel, sliced transversely, and polished on both faces. The core glass is then removed to create the micro-channels which are coated with a material to promote electron multiplication. Electrons impinging on one side of the plate tend to travel along the channels, perpendicular to the plate's faces, thus preserving a coherent image. This plate is situated behind the photocathode and amplifies the number of electrons that pass through it using a cascade effect. For every one electron that enters the plate, another approximately 10,000 electrons are added to it. This allows the tube to operate on a much lower voltage, as acceleration is not the principal source of light amplification, increasing battery life, tube life, and effectively eliminating distortion. As good as Generation 2 was, though, it was soon to be overshadowed by a new photocathode material. In an electron tube, a negatively charged electrode coated with a photosensitive compound. ... A micro-channel plate is a planar device which intensifies impinging radiation or particles by multiplication of electrons in small channels under the presence of a high electric field. ... In an electron tube, a negatively charged electrode coated with a photosensitive compound. ...

Generation 3

Generation 3 is the latest "generation" and is in use by the U.S. military and others. It is essentially generation 2 technology with a new photocathode material—gallium arsenide and a better MCP. Gallium arsenide provides far better response to near-infrared light. This is very important as the majority of starlight is in the IR spectrum. However, this comes at a cost of decreased sensitivity to blue light. This article is about the chemical compound. ...

Generation 3 tubes provide significantly better resolution and sensitivity and less noise, and have better overall light amplification than generation 2. Because it can be operated entirely passively outdoors, this allows soldiers to see at great distance at night without betraying their position as generations 0 and 1 technology did with IR illuminators.

There have been recent developments in image intensification tubes, modifying generation 3 devices to be "gated and filmless". This allows for even better resolution and sensitivity, and less "blooming" in urban environments. Some manufacturers have begun calling this "generation 4", but this term has not been officially adopted by the U.S. military.

One common misconception about night vision is that the battery life is extremely short. While this may have been true with generation 0 devices, modern generation 2 and 3 tubes can run for 40 hours or more using a single AA battery, using less power than a flashlight. Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ... For the Soviet military jet with the NATO designation Flashlight, see Yakovlev Yak-25. ...

Later Generations

There are newer night vision systems available. Generation 3 Ultra and Generation 4 tubes exist, but most civilian equipment remains based on Generation 3 equipment and lower. Generation 3 Ultra and 4 still use MCP technology, but are designed to offer greater range and higher resolution.

See also

• Night vision
• Infrared
• X-ray image intensifier