EOTech
Encyclopedia
EOTech designs, manufactures, and markets electro-optic products and systems. The company is headquartered in Ann Arbor, Michigan
. They produce holographic weapon sight
s for small arms
that have been adopted by various military and law enforcement agencies as close quarters battle
firearm sights.
They also have roots in the Environmental Research Institute of Michigan
(ERIM), a non-profit R&D institute. Of the many inventions by ERIM researchers, some were in the fields of synthetic aperture radar, laser holography, and aircraft head-up display
s.
s. EOTech was the first company to create these types of sights, having solved the problem of wavelength instability exhibited by laser diodes. They developed an achromatic holographic optics that compensates for any change in the emission wavelength of the laser diode with temperature. The sights are designed to be mounted on small arms via a MIL-STD-1913 Picatinny
or Weaver rail, and powered by either AA, N or CR123 size batteries for up to 1,100 hours of runtime. Sights display either a 65 MoA
ring with a 1 MoA dot in the center, a single 1 MoA dot, a vertical series of dots for bullet drop compensation in certain calibers, or, in the case of their less-lethal sights, a flared vase-like sight to assist in the aiming of bean-bag or rubber ball rounds commonly used in riot control. Bushnell marketed the non-military versions under the brand name "Holosight". The EOTech 553 is in U.S. military service under the designation SU-231/PEQ and M553 in the commercial market. A specialty sight for the grenade launcher has also been accepted by the U.S. military and is given the designation SU-253/PEQ.
An archery
sight was discontinued in November 2004, in line with the company's desire to concentrate on military and law-enforcement products.
s, the holographic weapon sight does not use a reflected reticle system.
Instead a representative reticle is recorded in three-dimensional space
onto holographic
film that is part of the optical viewing window. Like the reflector sight, the holographic sight's reticle uses collimated light
and therefor has an aim-point that can move with eye position. This is compensated for by having a holographic image that is set at a finite distance, in this case around 100 yards. The sight's parallax
due to eye movement is the size of the optical window at close range and diminishes to zero at the set distance. Since a laser is used as the light source, the aiming reticle can be an infinitely small dot whose perceived size is given by the acuity of the eye. For someone with 20/20 vision, it is about 1 MoA
.
To compensate for any change in the laser wavelength, the EOTech sight employs a holography grating that disperses the laser light by an equal amount but in the opposite direction as the hologram forming the aiming reticle. The result is a reticle that is stable with the change in temperature.
One requirement of holographic projection is a laser
. Lasers use more power and more complex driving electronics than an LED
of an equivalent brightness, reducing the amount of time a holographic sight can run on a single set of batteries.
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
. They produce holographic weapon sight
Holographic weapon sight
A holographic weapon sight or holographic diffraction sight is a non-magnifying gun sight that allows the user to look through a glass optical window and see a reticle image superimposed at a distance on the field of view...
s for small arms
Small arms
Small arms is a term of art used by armed forces to denote infantry weapons an individual soldier may carry. The description is usually limited to revolvers, pistols, submachine guns, carbines, assault rifles, battle rifles, multiple barrel firearms, sniper rifles, squad automatic weapons, light...
that have been adopted by various military and law enforcement agencies as close quarters battle
Close quarters battle
Close quarters combat or close quarters battle is a type of fighting in which small units engage the enemy with personal weapons at very short range, potentially to the point of hand-to-hand combat or fighting with hand weapons such as swords or knives...
firearm sights.
They also have roots in the Environmental Research Institute of Michigan
Environmental Research Institute of Michigan
-History:The Environmental Research Institute of Michigan began as Willow Run Laboratories in 1946, but was established as a private not for profit research institute when it formally separated from the University of Michigan in 1972. ERIM contributed to the development of remote sensing for...
(ERIM), a non-profit R&D institute. Of the many inventions by ERIM researchers, some were in the fields of synthetic aperture radar, laser holography, and aircraft head-up display
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
s.
Products
As of 2005, EOTech primarily manufactures holographic weapon sightHolographic weapon sight
A holographic weapon sight or holographic diffraction sight is a non-magnifying gun sight that allows the user to look through a glass optical window and see a reticle image superimposed at a distance on the field of view...
s. EOTech was the first company to create these types of sights, having solved the problem of wavelength instability exhibited by laser diodes. They developed an achromatic holographic optics that compensates for any change in the emission wavelength of the laser diode with temperature. The sights are designed to be mounted on small arms via a MIL-STD-1913 Picatinny
Picatinny rail
The Picatinny rail or MIL-STD-1913 rail or STANAG 2324 rail or a "Tactical Rail" is a bracket used on some firearms in order to provide a standardized mounting platform. A similar system is the Weaver rail mount.-Description:...
or Weaver rail, and powered by either AA, N or CR123 size batteries for up to 1,100 hours of runtime. Sights display either a 65 MoA
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
ring with a 1 MoA dot in the center, a single 1 MoA dot, a vertical series of dots for bullet drop compensation in certain calibers, or, in the case of their less-lethal sights, a flared vase-like sight to assist in the aiming of bean-bag or rubber ball rounds commonly used in riot control. Bushnell marketed the non-military versions under the brand name "Holosight". The EOTech 553 is in U.S. military service under the designation SU-231/PEQ and M553 in the commercial market. A specialty sight for the grenade launcher has also been accepted by the U.S. military and is given the designation SU-253/PEQ.
Archery
Archery is the art, practice, or skill of propelling arrows with the use of a bow, from Latin arcus. Archery has historically been used for hunting and combat; in modern times, however, its main use is that of a recreational activity...
sight was discontinued in November 2004, in line with the company's desire to concentrate on military and law-enforcement products.
Technology
Unlike reflector sightReflector sight
A reflector or reflex sight is a generally non-magnifying optical device that allows the user to look through a partially reflecting glass element and see an illuminated projection of an aiming point or some other image superimposed on the field of view...
s, the holographic weapon sight does not use a reflected reticle system.
Instead a representative reticle is recorded in three-dimensional space
Three-dimensional space
Three-dimensional space is a geometric 3-parameters model of the physical universe in which we live. These three dimensions are commonly called length, width, and depth , although any three directions can be chosen, provided that they do not lie in the same plane.In physics and mathematics, a...
onto holographic
Holography
Holography is a technique that allows the light scattered from an object to be recorded and later reconstructed so that when an imaging system is placed in the reconstructed beam, an image of the object will be seen even when the object is no longer present...
film that is part of the optical viewing window. Like the reflector sight, the holographic sight's reticle uses collimated light
Collimated light
Collimated light is light whose rays are parallel, and therefore will spread slowly as it propagates. The word is related to "collinear" and implies light that does not disperse with distance , or that will disperse minimally...
and therefor has an aim-point that can move with eye position. This is compensated for by having a holographic image that is set at a finite distance, in this case around 100 yards. The sight's parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
due to eye movement is the size of the optical window at close range and diminishes to zero at the set distance. Since a laser is used as the light source, the aiming reticle can be an infinitely small dot whose perceived size is given by the acuity of the eye. For someone with 20/20 vision, it is about 1 MoA
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
.
To compensate for any change in the laser wavelength, the EOTech sight employs a holography grating that disperses the laser light by an equal amount but in the opposite direction as the hologram forming the aiming reticle. The result is a reticle that is stable with the change in temperature.
One requirement of holographic projection is a laser
Laser diode
The laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common type of laser diode is formed from a p-n junction and powered by injected electric current...
. Lasers use more power and more complex driving electronics than an LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....
of an equivalent brightness, reducing the amount of time a holographic sight can run on a single set of batteries.