The History of Night Vision Devices

Night vision devices were originally developed for military use, and used extensively in the Vietnam War. Night vision devices are also used by urban and rural police forces as well as in some higher-end cars, although the primary use is for hunters and recreational users. The United States military developed night vision technology programs by the late 1940's, and by the 1950's had come up with infrared viewing systems, an active technology, meaning it used a directed beam of infrared light. Unfortunately, although this beam was invisible to the naked eye, opponents armed with the same technology could pick up the beam, rendering them somewhat impractical.

Starlight Technology

ITT Corporation in Roanoke, Virginia, produced night vision devices for the military in 1958, then by 1965 the Department of Defense had founded its own night vision laboratory which was wholly dedicated to improving the existing night vision technology. The first workable passive night vision system, known as the Starlight system, could pick up and amplify images seen only by starlight, and were used in combat for the first time during the Vietnam War. After the Vietnam War, the technology developed into smaller, less bulky night vision devices with better resolution which were known as Generation 2.

Generation 3 Technology

Generation 3 technology came along in the late 1980's, and this technology used gallium arsenide for the photo cathode material inside the image intensifier tube, creating better resolution in extremely low light situations. This technology was used in the Persian Gulf War, allowing the troops to see not only in the dark, but in the dust and smoke as well. By the time the late 1990's rolled around the Department of Defense had significantly reduced its funding for night vision development, and started searching for consumer markets for its night vision developments. While individuals in the United States can buy night vision devices, the export of these products is restricted.

Manufacturing Process

Over 400 steps are involved in making the image intensifier tube for the night vision products. The first major step is in making the photo cathode begins when workers drop a wafer of gallium arsenide onto the glass, heating it up and melting the gallium arsenide to the glass. The part is next put into a press, binding the gallium arsenide substrate, and being ground and polished by workers. The glass micro channel plate is formed using a two-draw process, which fits a rod into a hollow tube of another type of glass, called cladding. After both draws, the bundle of fibers is heated and pressed under a vacuum, fusing all the fibers together, then the plates are finished with an acid etch to remove the cladding glass. Once the cladding glass is removed, the revealed channels are coated with nickel-chrome, then a film of aluminum oxide is set onto both surfaces, so the channel can carry electrical charge.

After this the phosphor screen and tube body are assembled with a screen of small fiber optic disc, probably supplied by a subcontractor. The screen is dropped into a flange and bonded with a ring of fusible material called frit, which is a special glass compound, then other metal parts are fitted over the screen and sent through a furnace which melts the frit and bonds all the components together. Once everything is cooled, cleaned and polished, the phosphor is sprayed or brushed on. Workers then fit a series of small metal and ceramic rings, all with a specific function to be loaded into the tube, adding insulators and conductors. Once all the main components are manufactured, they are loaded by hand into the tube body; an extremely delicate operation. Finally the unit is taken to an exhaust station where air is removed from the tube, leaving a vacuum.

The Future of Night Vision

Since the night vision industry has become so available to the non-military consumer, prices may start to decrease until the technology becomes somewhat affordable. Presently night vision technology is used by law enforcement and search and rescue teams in addition to the outdoor consumer, but the market is expected to widen, causing prices to drop.