Generation 0The first application for night vision was for American snipers in World War II. 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.
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.
Generation 1Generation 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.
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 2Generation 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.
Generation 3Generation 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.
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.
Later GenerationsThere 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.
Night vision equipment on
www.ATNcorp.com
ATN Night Star is the smallest and lightest Night Vision Scope. Gen 1 Night Vision on the budget that fits the palm of your hand.
Posts
