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A night-vision device (NVD), also known as a night optical/observation device (NOD) or night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision.
The device enhances ambient visible light and converts near-infrared light into visible light which can then be seen by humans; this is known as I2 (image intensification). By comparison, viewing of infrared thermal radiation is referred to as thermal imaging and operates in a different section of the infrared spectrum.
A night vision device usually consists of an image intensifier tube, a protective housing, and an optional mounting system. Many NVDs also include a protective sacrificial lens, mounted over the front/objective lens to prevent damage by environmental hazards,<ref name="<sacrif">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> while some incorporate telescopic lenses. An NVD image is typically monochrome green, as green was considered to be the easiest color to see for prolonged periods in the dark.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Night vision devices may be passive, relying solely on ambient light, or may be active, using an IR (infrared) illuminator.
Night vision devices may be handheld or attach to helmets. When used with firearms, an IR laser sight is often mounted to the weapon. The laser sight produces an infrared beam that is visible only through an NVD and aids with aiming.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Some night vision devices are made to be mounted to firearms. These can be used in conjunction with weapon sights or standalone; some thermal weapon sights have been designed to provide similar capabilities.<ref name="nv/therm clipon sights">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
These devices were first used for night combat in World War II and came into wide use during the Vietnam War.<ref name="autogenerated4">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The technology has evolved since then, involving "generations"<ref>as defined by the US Army Night Vision and Electronic Sensors Directorate (NVESD)</ref> of night-vision equipment with performance increases and price reductions. Consequently, though they are commonly used by military and law enforcement agencies, night vision devices are available to civilian users for applications including aviation, driving, and demining.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
HistoryEdit
In 1929 Hungarian physicist Kálmán Tihanyi invented an infrared-sensitive electronic television camera for anti-aircraft defense in the UK.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Night vision technology prior to the end of World War II was later described as Generation 0.<ref name="autogenerated4" />
Night-vision devices were introduced in the German Army as early as 1939Template:Citation needed and were used in World War II. AEG started developing its first devices in 1935. In mid-1943, the German Army began testing infrared night-vision devices and telescopic rangefinders mounted on Panther tanks. Two arrangements were constructed. The Sperber FG 1250 ("Sparrow Hawk"), with a range of up to Template:Convert, had a Template:Convert infrared searchlight and an image converter operated by the tank commander.
From late 1944 to March 1945 the German military conducted successful tests of FG 1250 sets mounted on Panther Ausf. G tanks (and other variants). During the war, approximately 50 (or 63) Panthers were equipped with the FG 1250 and saw combat on both the Eastern and Western Fronts. The "Vampir" man-portable system for infantry was used with StG 44 assault rifles.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Parallel development occurred in the US. The M1 and M3 infrared night-sighting devices, also known as the "sniperscope" or "snooperscope", saw limited service with the US Army in World War II<ref>Template:Cite magazine</ref> and in the Korean War, to assist snipers.<ref name="autogenerated4" /> These were active devices, using an infrared light source to illuminate targets. Their image-intensifier tubes used an anode and an S-1 photocathode, made primarily of silver, cesium, and oxygen, and electrostatic inversion with electron acceleration produced gain.<ref name="autogenerated3">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
An experimental Soviet device called the PAU-2 was field-tested in 1942.
In 1938 the British Admiralty assumed responsibility for British military infra-red research. They worked first with Philips until the fall of the Netherlands, then with Philips' UK subsidiary Radio Transmission Equipment Ltd., and finally with EMI, who in early 1941 provided compact, lightweight image converter tubes. By July 1942 the British had produced a binocular apparatus called 'Design E'. This was bulky, needing an external power pack generating 7,000 volts, but saw limited use with amphibious vehicles of 79th Armoured Division in the 1945 crossing of the Rhine. Between May and June 1943, 43rd (Wessex) Infantry Division trialled man-portable night vision sets, and the British later experimented with mounting the devices to Mark III and Mark II(S) Sten submachine guns. However, by January 1945 the British had only made seven infra-red receiver sets. Although some were sent to India and Australia for trials before the end of 1945, by the Korean War and Malayan Emergency the British were using night vision equipment supplied by the United States.<ref>Template:Cite journal</ref>
Early examples include:
- FG 1250 Sperber
- ZG 1229 Vampir
- PAU-2
- PNV-57A tanker goggles
- SU-49/PAS-5<ref name="pas-5, pas-6" />
- T-120 Sniperscope, 1st model (World War II)
- M2 Sniperscope, 2nd model (World War II)
- M3 Sniperscope, 4th model (Korean War)
- AN/PAS-4 (early Vietnam War)<ref name="pas-4">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
After World War II, Vladimir K. Zworykin developed the first practical commercial night-vision device at Radio Corporation of America, intended for civilian use. Zworykin's idea came from a former radio-guided missile.<ref>Pennsylvania State University. Zworykin, Vladimir Template:Webarchive. Biographical sketch.</ref> At that time, infrared was commonly called black light, a term later restricted to ultraviolet. Zworykin's invention was not a success due to its large size and high cost.<ref>Template:Cite magazine</ref>
United StatesEdit
Generation 1Edit
First-generation passive devices developed by the US Army in the 1960s were introduced during the Vietnam War. They were an adaptation of earlier active technology and relied on ambient light instead of using an extra infrared light source. Using an S-20 photocathode, their image intensifiers amplified light around Template:Val-fold,<ref name="autogenerated6">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> but they were quite bulky and required moonlight to function properly.
Examples:
- AN/PVS-1 Starlight scope<ref name="pvs-1 and 2 showcase">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref><ref name="pvs-1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- AN/PVS-2 Starlight scope<ref name="pvs-2 nsn">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref><ref name="pvs-1 and 2 showcase"/>
- AN/PAS 6 Varo Metascope<ref name="pas-5, pas-6">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
Generation 2Edit
1970s second-generation devices featured an improved image-intensifier tube using a micro-channel plate (MCP)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> with an S-25 photocathode.<ref name="autogenerated3" /> This produced a much brighter image, especially around the edges of the lens. This led to increased clarity in low ambient-light environments, such as moonless nights. Light amplification was around Template:Val.<ref name="autogenerated6" /> Image resolution and reliability improved.
Examples:
- AN/PVS-3 Miniaturized night vision sight
- AN/PVS-4<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- AN/PVS-5<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- SUPERGEN<ref name="opto review article">Template:Cite journal</ref>
Later advances brought GEN II+ devices (equipped with better optics, SUPERGEN tubes, improved resolution and better signal-to-noise ratios), though the label is not formally recognized by the NVESD.<ref name="opto review article"/>
Generation 3Edit
Third-generation night-vision systems, developed in the late 1980s, maintained the MCP from Gen II, but used a gallium arsenide photocathode, with improved resolution. GA photocathodes are primarily manufactured by L3Harris Technologies and Elbit Systems of America and imaged light from 500-900 nm.<ref name="photonis 4g"/> In addition, the MCP was coated with an ion barrier film to increase tube life. However, the ion barrier allowed fewer electrons to pass through. The ion barrier increased the "halo" effect around bright spots or light sources. Light amplification (and power consumption) with these devices improved to around Template:Val–Template:Val.<ref name="autogenerated6" />
Examples:
- AN/PVS-7<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- AN/NVS-7
- AN/PVS-10
- AN/PVS-14<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- AN/PNVS-14
- AN/PVS-17
- CNVS-4949<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- PN-21K
Auto-gatingEdit
Autogating (ATG) rapidly switches the power supply's voltage to the photocathode on and off. These switches are rapid enough that they are not detectable to the human eye and peak voltage supplied to the night vision device is maintained.<ref name="Photonics Montoro essay"/> This reduces the "duty cycle" (ie. the amount of time that the tube has power running through it) which increases the device's lifespan.<ref name="photonis auto-gating"/> Autogating also enhances the Bright-Source Protection (BSP), which reduces the voltage supplied to the photocathode in response to ambient light levels. Automatic Brightness Control (ABC) modulates the amount of voltage supplied to the microchannel plate (rather than the photocathode) in response to ambient light. Together, BSP and ABC (alongside autogating) serves to prevent temporary blindness for the user and prevent damage to the tube when the night vision device is exposed to sudden bright sources of light,<ref name="Photonics Montoro essay"/> like a muzzle flash or artificial lighting.<ref name="photonis auto-gating"/> These modulation systems also help maintain a steady illumination level in the user's view that improves the ability to keep "eyes on target" in spite of temporary light flashes. These functions are especially useful for pilots, soldiers in urban environments, and special operations forces who may be exposed to rapidly changing light levels.<ref name="photonis auto-gating"/><ref name="Chief naval training"/>
Generation 3+ (GEN III OMNI I–IX)Edit
OMNI, or OMNIBUS, refers to a series of contracts through which the US Army purchased GEN III night vision devices. This started with OMNI I, which procured AN/PVS-7A and AN/PVS-7B devices, then continued with OMNI II (1990), OMNI III (1992), OMNI IV (1996), OMNI V (1998), OMNI VI (2002), OMNI VII (2005),<ref name="def indus daily"/> OMNI VIII, and OMNI IX.<ref name="TFB nv gens"/>
However, OMNI is not a specification. The performance of a particular device generally depends upon the tube which is used. For example, a GEN III OMNI III MX-10160A/AVS-6 tube performs similarly to a GEN III OMNI VII MX-10160A/AVS-6 tube, even though the former was manufactured in ~1992 and the latter ~2005.<ref name="TFB nv gens"/><ref name="tnvc buyer"/>
One particular technology, PINNACLE is a proprietary thin-film microchannel plate technology created by ITT that was included in the OMNI VII contract. The thin-film improves performance.<ref name="tnvc buyer"/>
GEN III OMNI V–IX devices developed in the 2000s and onward can differ from earlier devices in important ways:
- An automatic gated power supply system regulates the photocathode voltage, allowing the NVD to instantaneously adapt to changing light conditions.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- A removed or greatly thinned ion barrier that decreases the number of electrons that are rejected by GEN III MCP, hence resulting in less image noise.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> The disadvantage to a thin or removed ion barrier is the overall decrease in tube life from a theoretical Template:Val mean time to failure (MTTF) for standard Gen III type, to Template:Val MTTF for thin film types. This loss is largely negated by the low number of image-intensifier tubes that reach Template:Val of operation before requiring replacement.Template:Citation needed
The consumer market sometimes classifies such systems as Generation 4, and the United States military describes these systems as Generation 3 autogated tubes (GEN III OMNI V-IX). Moreover, as autogating power supplies can be added to any previous generation of night-vision devices, autogating capability does not automatically put the devices in a particular OMNI classification. Any postnominals appearing after a generation type (i.e., Gen II+, Gen III+) indicate improvement(s) over the original specification's requirements.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Examples:
- AN/PVS-22<ref name="autogenerated5">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- NVS-22
- Binocular Night Vision Device (BNVD) (AN/PVS-15, AN/PVS-21, AN/PVS-23, AN/PVS-31A, AN/PVS-31D)
- Ground Panoramic Night Vision Goggle (GPNVG-18)
Figure of meritEdit
Figure of merit (FoM) is a quantitative measure of a NVD's effectiveness and clarity. It is calculated using the number of line pairs per millimeter that a user can detect multiplied by the image intensifier's signal-to-noise (SNR) ratio.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="nitewalker gen"/><ref name="TFB nv gens"/><ref name="nato response paper">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In the late 1990s, innovations in photocathode technology significantly increased the SNR, with new tubes surpassing Gen 3 performance.
By 2001, the United States federal government concluded that a tube's generation was not a determinant performance factor, obsoleting the term as a basis of export regulations.
The US government has recognized the fact that the technology itself makes little difference, as long as an operator can see clearly at night. Consequently, the United States bases export regulations directly on the figure of merit.
ITAR regulations specify that US-made tubes with a FOM greater than 1400 are not exportable; however, the Defense Technology Security Administration (DTSA) can waive that policy on a case-by-case basis.
Fusion night visionEdit
Fusion night vision combines I² (image intensification) with thermal imaging, which functions in the medium (MWIR 3-5 μm) and/or long (LWIR 8-14 μm) wavelength range.<ref name="flir thermal wavelength"/> Initial models appeared in the 2000s.<ref name="def indus daily"/> Dedicated fusion devices and clip-on imagers that add a thermal overlay to standard I² night vision devices are available.<ref name="TFB Fusion"/> Fusion combines excellent navigation and fine details (I²), with easy heat signature detection (imaging).
Fusion modes include night vision with thermal overlay, night vision only, thermal only, and others such as outline (which outlines objects that have thermal signatures) or "decamouflage", which highlights all objects that are of near-human temperature. Fusion devices are heavier and more power hungry than I²-only devices.<ref name="fusion overview" />
One alternative is to use an I² device over one eye and a thermal device over the other eye, relying on the human visual system to provide a binocular combined view.<ref name="TFB Fusion" /><ref name="noisefighters pseudo-fusion bridge" />
ExamplesEdit
- AN/PSQ-20 ENVG (Enhanced Night Vision Goggles)
- AN/PSQ-36 FGE (Fusion Goggle Enhanced, previously FGS for Fusion Goggle System)
- AN/PSQ-42 ENVG-B (Enhanced Night Vision Goggles-Binocular)
- AN/PSQ-44 ENVG-B (Enhanced Night Vision Goggles-Binocular)
- AN/PAS-29 COTI/E-COTI: (Enhanced) Clip-On Thermal Imager
Out of bandEdit
Out of Band (OOB) refers to night vision technologies that operate outside the 500-900 nm NIR (near infrared) frequency range. This is possible with dedicated image intensifier tubes or with clip-on devices.
AdvantagesEdit
- OOB devices might see more on a starlit night because OOB devices intensify any ambient, UV, or SWIR light.
- OOB devices image 1064 nm light, which can help JTACs and other FACs when marking targets with a laser designator, which typically use 1064 nm light, which is barely visible to Gen III.<ref name="photonis 4g" /><ref name="spie see-spot" />
- OOB light is not visible to most commercial devices. Night vision has proliferated among countries such as Russia and China, and into the hands of armed groups such as the Taliban Red Unit.<ref name="nvg proliferation" /> Friendly forces using night vision equipment such as IR illuminators, IR strobes, or IR lasers, can be spotted. OOB tech are much more difficult to spot with Gen III (depending on wavelength and intensity).<ref name="TFB OOB info" /><ref name="blackice flfc 2016" />
- OOB devices that operate in the 1550 nm range can perceive typical laser rangefinders.<ref name="L3H spear" />
ExamplesEdit
- Ground personnel, helmet-mounted imagers):
- Photonis 4G INTENS image intensifier tubes (350-1100 nm)<ref name="blackice flfc 2016" /><ref name="photonis 4g" />
- Optics 1 AN/PAS-34 E-COSI (Enhanced Clip-On SWIR Imager) (900-1700 nm)<ref name="e-cosi wavelength" />
- Optics 1 COSMO (Clip-On SWIR Monocular)<ref name="Optics 1 COSMO" />
- Photonis' 4G HyMa (Hybrid Multi-Alkali) image intensifier tubes (bandwidth of 350-1100 nm, from near UV to IR)
- Safran Optics 1's AN/PAS-34 E-COSI (Enhanced Clip-On SWIR Imager)provides an overlay (in the 900-1700 nm range).<ref name="e-cosi wavelength" />
- Ground personnel, weapon-mounted lasers):
- B.E. Meyers & Co. MAWL-CLAD (Modular Aiming Weapon Laser--Covert Laser Aiming Device) (1064 nm laser)<ref name="TFB MAWL-CLAD" /><ref name="BE Meyers MAWL-CLAD announce" /><ref name="Scopex MAWL-CLAD listing" />
- LA-17/PEQ D-PILS (Dual-band Pointer and Illuminator Laser System) (1400-1600 nm)<ref name="la-17/peq report" /><ref name="LA-17/PEQ NSN" />
- Rheinmetall LM-VAMPIR (Laser Module--VAriable Multi Purpose InfraRed)<ref name="LM-VAMPIR" />
- AN/PSQ-23 STORM, STORM-PI, STORM-SLX, STORM II; and L3Harris SPEAR (1570 nm)<ref name="la-17/peq report" /><ref name="L3H spear" />
- Optics 1 ICUGR (Integrated Compact Ultralight Gun-mounted Rangefinder) (1550 nm)<ref name="Optics 1 ICUGR" />
- Rheinmetall FCS-RPAL (Fire Control System--Rheinmetall Precision Aiming Laser) (1550 nm)<ref name="FCS-RPAL" />
- Rheinmetall FCS-TRB (Fire Control System--TacRay Ballistic) (1550 nm)<ref name="FCS-TACRAY" />
- Wilcox RAPTAR S (Rapid Targeting and Ranging Module) (1550 nm)<ref name="wilcox raptar s" />
- Wilcox MRF Xe (Micro Range Finder--Enhanced) (1550 nm)<ref name="wilcox mrf xe" />
- B.E. Meyers & Co. IZLID Ultra 1064 and 1550 (Infrared Zoom Laser Illuminator Designator) (1064 nm, 1550 nm)<ref name="izlid swir oob" />
- Optics 1 CTAM (Coded Target Acquisition Marker) (1064 nm)<ref name="Optics 1 CTAM" />
Wide field of viewEdit
Night vision devices typically have a limited field of view (FoV); the commonly used AN/PVS-14 has a FoV of 40,<ref name="m914a" /> less than the 95° monocular horizontal FoV and humans' 190° binocular horizontal FoV.<ref name="human fov"/> This forces users to turn their heads to compensate. This is particularly evident when flying, driving, or CQB, which involves split second decisions. These limitations led many SF/SOF operators to prefer white light rather than night vision when conducting CQB.<ref name="TNVC gpnvg white paper"/> As a result, much time and effort has gone into research to develop a wider FoV solution.<ref name="tnvc wfov white paper" />
Panoramic night vision gogglesEdit
Panoramic night vision goggles (PNVG) increase FoV by increasing the number of sensor tubes. This solution adds size, weight, power requirements, and complexity.<ref name="tnvc wfov white paper" /> An example is GPNVG-18 (Ground Panoramic Night Vision Goggle).<ref name="gizmodo bin laden story" /> These goggles, and the aviation AN/AVS-10 PNVG from which they were derived, offer a 97° FoV.<ref name="TNVC gpnvg white paper" />
Examples:
- GPNVG-18
- AN/AVS-10
Foveated night visionEdit
Foveated night vision (F-NVG) uses specialized WFoV optics to increase the field of view through an intensifier tube. The fovea refers to the part of the retina which is responsible for central vision. These devices have users look "straight through" the tubes so light passing through the center of the tube falls on the foveal retina, as is the case with traditional binocular NVGs. The increased FoV comes at the price of image quality and edge distortions.<ref name="tnvc wfov white paper" /><ref name="kent pvs-15 wfov" /><ref name="kent asked to wfov" /><ref name="SSD wfov" /> Examples:
- WFoV F-NVG retrofit AN/PVS-15 goggles
- WFoV BNVD (combined F-NVG and DIT-NVG variant of AN/PVS-31A)
Diverging image tubeEdit
Diverging image tube (DIT) night vision increases FoV by angle the tubes slightly outward. This increases peripheral FoV but causes distortion and reduced image quality. With DIT, users are no longer looking through the center of the tubes (which provides the clearest images) and light passing through the center of the tubes no longer falls on the fovea.
Examples:
- AN/PVS-25 (2000s).<ref name="tnvc wfov white paper" />
- WFoV BNVD: variant of the AN/PVS-31A which incorporates both F-NVG and DIT-NVG. The foveal WFoV optics increase the FoV of each tube from 40° to 55°, while the angulation of the tubes positions them so there is a 40° overlap of binocular vision in the center and a total 70° FoV. It offers a FoM of 2706, better than the FoM in either the GPNVG-18 and the standard AN/PVS-31A.<ref name="USASOC evol capabilities" /><ref name="tnvc wfov white paper" />
- Noise Fighters Panobridge: binocular bridge mount which combines two AN/PVS-14 monoculars and allows them to be angled. outward or positioned parallel<ref name="noisefighters panobridge" /><ref name="tnvc wfov white paper" />
DigitalEdit
Some night vision devices, including several of the ENVG (AN/PSQ-20) models, are "digital". Introduced in the late 2000s, these allow transmission of the image, at the cost of increased size, weight, power usage.<ref name="def indus daily"/>
High-sensitivity digital camera technology enables NVGs that combine a camera and a display instead of an image intensifier. These devices can offer Gen-1-equivalent quality at a lower cost.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> At the higher end, SiOnyx has produced digital color NVGs. The "Opsin" of 2022 has a form factor and helmet weight similar to an AN/PVS-14, but requires a separate battery pack. It offers a shorter battery life and lower sensitivity.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It can however tolerate bright light and process a wider range of wavelengths.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Other technologiesEdit
Ceramic Optical Ruggedized Engine (CORE)<ref name="about-armasight">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> produces higher-performance Gen 1 tubes by replacing the glass plate with a ceramic plate. This plate is produced from specially formulated ceramic and metal alloys. Edge distortion is improved, photo sensitivity is increased, and the resolution can be as high as 60 Template:Abbr/mm. CORE is still designated Gen 1 as it does not use a microchannel plate.
A night-vision contact lens prototype places a thin strip of graphene between layers of glass that reacts to photons to brighten dark images. Prototypes absorb only 2.3% of light, which is considered not yet enough for practical use by its developers.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The Sensor and Electron Devices Directorate (SEDD) of the US Army Research Laboratory developed quantum-well infrared detector (QWID). This technology's epitaxial layers use a gallium arsenide (GaAs) or aluminum gallium arsenide system (AlGaAs) which are particularly sensitive to mid-length infrared waves. The Corrugated QWID (CQWID) broadens detection capacity by using a resonance superstructure to orient more of the electric field parallel so that it can be absorbed, although cryogenic cooling between 77 K and 85 K is required. QWID technology may be appropriate for continuous surveillance viewing due to its claimed low cost and uniformity in materials but it has yet to enter commercial production.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Materials from the II–VI compounds, such as HgCdTe, are used for high-performance infrared light-sensing cameras. An alternative within the III–V family of compounds is InAsSb, which is common in opto-electronics such as DVDs and mobile phones. A graded layer with increased atomic spacing and an intermediate layer of GaAs substrate can trap any potential defects.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Metasurface-based upconversion technology provides a night-vision film that weighs less than a gram and can be placed across ordinary glasses. Photons pass through a resonant non-local lithium niobate metasurface with a pump beam. The metasurface boosts the photons' energy, pushing them into the visible spectrum without converting them to electrons. Cooling is not required and visible and infrared light appear in a single image. Its frequency range is 1550-nm infrared to visible 550-nm light. Because, traditionally, night-vision systems capture side-by-side views from each spectrum, they can't produce identical images unlike films applied to ordinary glasses.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Soviet Union/RussiaEdit
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The Soviet Union, and after 1991 the Russian Federation, have developed their own night-vision devices. Models used after 1960 by the Russian/Soviet Army are designated 1PNxx (Template:Langxxx), where 1PN is the GRAU index of night-vision devices. The PN stands for pritsel nochnoy (Template:Langx), meaning "night sight", and the xx is the model number. Different models introduced around the same time use the same type of batteries and mounting mechanism. Multi-weapon models have replaceable elevation scales, with one scale for the ballistic arc of each. Supported weapons include the AK family, sniper rifles, light machine guns and hand-held grenade launchers.
- 1PN34 refractor-based night sight for a range of small arms and grenade launchers (photo)
- 1PN50 refractor-based night observation binoculars.<ref>Template:Cite book</ref>
- 1PN51 reflector-based night sight for a range of small arms and grenade launchers.<ref>Template:Cite book</ref>
- 1PN51-2 reflector-based night sight for the RPG-29.<ref>Template:Cite book</ref>
- 1PN58 refractor-based night sight for a range of small arms and grenade launchers.<ref>Template:Cite book</ref>
- 1PN93-2 reflector-based night sight for the RPG-7D3, see photo.
- 1PN110, a more recent (~Gen 3) night sight for the RPG-29.<ref name=1pn110_113>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- 1PN113, a night sight similar to the 1PN110, for the SV-98 sniper rifle.<ref name=1pn110_113/>
The Russian army fielded a series of so-called Template:Ill (Template:Langx). The counter-sniper night sight is an active system that uses laser pulses from a laser diode to detect reflections from the focal elements of enemy optical systems and estimate their distance:<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- 1PN106 counter-sniper night sight for the SVD sniper rifle and its SVDS variant.
- 1PN119 counter-sniper night sight for the PKMN and Pecheneg light machine guns.
- 1PN120 counter-sniper night sight for the SVDK sniper rifle.
- 1PN121 counter-sniper night sight for the ASVK large caliber sniper rifle.
- 1PN123 counter-sniper night sight for the SV-98 sniper rifle.
Legal restrictionsEdit
- Belgium: firearms legislation forbids night-vision devices that can be mounted on a firearm.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- Czech Republic: not regulated.<ref name= "zbrojnice-novela-2021">{{#invoke:citation/CS1|citation
|CitationClass=web }}, </ref> Previously only available for hunting.Template:Citation needed
- Germany: law forbids such devices if their purpose is to be mounted on firearms<ref>Section 19 5a of the German Bundesjagdgesetz (BJagdG) states: "It is forbidden to use artificial light sources, mirrors, devices to illuminate or light targets, or night vision devices with image converters or electronic amplification intended for guns." These aids are not banned for observation purposes but for catching or killing game.</ref><ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> except for hunting wild boars.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- Iceland: night-vision devices for hunting is prohibited, although owning the devices is permitted.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- India: civilian possession and trading of night-vision scopes is prohibited without permission from Union home ministry.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- Netherlands: possession is not regulated, but night-vision devices mounted on firearms require a permit. Using mounted night-vision equipment for hunting requires a permit in the Veluwe for hunting wild boar.
- New Zealand: rescue helicopter services use US-made Gen3 goggles for use only according to US export regulations.<ref name="CAANZ">"Seeing in the Dark", Vector, magazine of the Civil Aviation Authority of New Zealand, January/February 2008, pages 10–11.</ref> Use of NVD for shooting non-indigenous game animals, such as rabbits, hares, deer, pigs, tahr, chamois, goats, wallabies, is permitted.
- United States: a 2010–2011 summary of state hunting regulations for the use of night-vision equipment in hunting<ref name="HiTechRedNeck2010">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> listed 13 states in which the equipment is prohibited, 17 states with various restrictions (e.g. only for certain non-game species, and/or in a certain date range), and 20 states without restrictions. It did not summarize the regulations for thermal-imaging equipment.
- California: possessing a device "designed for or adaptable to use on a firearm which, through the use of a projected infrared light source and electronic telescope, enables the operator thereof to visually determine and locate the presence of objects during the night-time" is a misdemeanor.<ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> This essentially covers scopes using Gen0 technology, but not subsequent generations.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- Minnesota, as of 2014, "A person may not possess night vision or thermal imaging equipment while taking wild animals or while having in possession [an uncased and loaded weapon] that could be used to take wild animals."<ref name="MN-Law">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref> Law-enforcement and military use is exempt.<ref name="Orrick2016">Template:Cite news</ref>
See alsoEdit
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- List of military electronics of the United States
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- Javelin man portable missile thermal sight
ReferencesEdit
External linksEdit
- TNVC guide to night vision generations and specifications Template:Usurped on 19 July 2021
- Nitewalker guide to night vision equipment Template:Usurped on 15 August 2021
- Night Vision Devices Modeling and Optimal Design Template:Usurped on 6 May 2022
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|CitationClass=web }}
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US patentsEdit
- {{#if:D248860
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:D248860 }}|D248860}} US D248860 - Night vision Pocketscope]
|{{US patent|123456|link text}}}}
- {{#if:4707595
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:4707595 }}|4707595}} US 4707595 - Invisible light beam projector and night vision system]
|{{US patent|123456|link text}}}}
- {{#if:4991183
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:4991183 }}|4991183}} US 4991183 - Target illuminators and systems employing same]
|{{US patent|123456|link text}}}}
- {{#if:6075644
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:6075644 }}|6075644}} US 6075644 - Panoramic night vision goggles]
|{{US patent|123456|link text}}}}
- {{#if:6158879
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:6158879 }}|6158879}} US 6158879 - Infrared reflector and illumination system]
|{{US patent|123456|link text}}}}
- {{#if:6911652
|[{{#ifeq:|uspto|http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=%7Chttps://patents.google.com/patent/US}}{{#iferror:{{#expr:6911652 }}|6911652}} US 6911652 - Low Light Imaging Device]
|{{US patent|123456|link text}}}}