Classification of Night Vision Devices

People love comfort. And this is one factor that stimulates him to develop, invent new things, improve existing ones, or create alternatives. 

So, about a century ago, inventors began to develop night vision devices to make it easier for soldiers to see in the dark during night operations. The machine proliferated because physicists and engineers managed to meet this challenge. 

After the war ended, night vision technology continued to be in great demand among the military, but it also quickly assimilated into civilian life. Today, these devices are used for hunting, security guards, rescue services, paintball, airsoft players, etc. Each area of use has its specifics and requirements for the device. Considering these factors, the classification of night vision devices is based on the principle of technology improvements or their generation and appearance.

Night Vision Technology 

The standard image enhancement technology used for the ABL works as follows. The device captures any light, for example, from the moon, and passes it through a photocathode. The photocathode, in turn, converts photons (light) into electrons. These electrons then “strike” a tube covered with a fluorescent phosphor, thus reproducing an image. 

Usually, the tube is filled with green phosphor, so the image is green. The fact is that the human eye is susceptible to wavelengths of light of this color. However, CCTVs on the market already illuminate objects and people using a white phosphor. This technology makes the image more detailed and contrasty. 

An electron-optical converter is one of the most essential parts of any night vision device. The materials used to create it, improve its functioning, and technology determine which generation the device will belong to.

Generations of Night Vision Devices

Any night vision device will be categorized by generation. The very first is Gen 0. The first models were invented in Germany during World War II. Of course, they were large and heavy, making them uncomfortable to use. In addition, the range of their vision was 200-700 meters. Since it was a very young technology, the EOP needed more light. 

Gen 1 Devices have a short range of visibility – 100-200 meters. This can be improved by using an additional infrared source. Another disadvantage of this generation of devices is the loss of clarity from the center of the image, but with suitable optics, this can also be compensated for. The light gain of such models ranges from 900.

Gen 1+. In the 60s of the 19th century, the United States began an era of fiber optics development. This allowed us to improve the first generation of EOPs, which gave rise to the production of Generation I+. The light gain of such devices has already reached 1000-1200, and the visibility range increased significantly. Another advantage was a more precise picture across the entire image plane.

Gen 2. 10 years after the previous improvement, an additional amplifier, a microchannel plate, was used to improve the device’s performance. This increased the light gain to 25000-50000 and the working life to 1000-3000 hours. The photocathode sensitivity of this generation of devices ranges from 240-350 μA/lm (all previous models had a sensitivity of 150-200 μA/lm). Additionally, all models of this generation are equipped to adjust the brightness manually. 

Gen 2+. The main difference of this generation was the lack of an electron acceleration chamber. This affected the light gain – they do not exceed 35000, but, oddly enough, it did not affect the picture. The reason for this was the increased sensitivity of the photocathode – in such devices, it reaches 280-550 μA/lm, which is the reason for the higher image quality of these CCDs. Additionally, devices of this generation are equipped with automatic brightness control. Another advantage is the absence of the need for additional infrared illumination and an extended service life (2000-5000 hours).

Gen 3. The first devices of this generation were introduced in 1982. A significant difference from previous generations was the use of gallium arsenide as the basis for the photocathode. This made it possible to increase its sensitivity to 1200-2700 μA/lm and the light gain to 100000-15000. Devices of this generation practically do not require additional illumination but are “afraid” of side illumination. At the same time, the use of gallium arsenide affected the complexity of production, increasing their cost several times.

Types of Night Vision Devices 

As we’ve already mentioned, night vision devices differ not only in their technology but also in their appearance: binoculars, glasses, monoculars, or a scope. 

It is impossible to say which one is more comfortable to use because you will always choose what is comfortable for you and the device that meets your requirements. 

Night vision binoculars (NVBs) are compact and functional devices for surveillance in the dark. The devices monitor nature or objects at medium and long distances and protect the outer perimeter. They can recognize moving and stationary targets at 200-700 meters. Binocular vision is more familiar to humans, so using binoculars significantly reduces eye strain and allows you to cover more space with your eyes.

Night vision goggles (NVGs) have no magnification (1x), which allows you to move freely and accurately navigate in space. The goggles are mounted on the head or helmet using a system of tighteners and straps that securely hold the device in a comfortable position for the user. They can be tilted upward at any time. Thanks to the reliable and convenient attachment of the accessory to the head, it is possible to hold a weapon, video camera, or camera. Night vision goggles allow you to drive at night when the headlights cannot be used for some reason or when traveling on unfamiliar rough terrain.  The device is popular among hunters, security guards, tourists, rescuers, researchers, and anyone working in the dark.

Night vision monocular. A device that has functions similar to binoculars, with the difference that you can observe with only one eye. Due to its shape, it will be much cheaper than the previous options. Some models even have mounts that allow them to be installed on a rifle. Of course, they are more potent than sights, but it is impractical because of their weight, which creates an additional load on the weapon. And it does not have a reticle.

Night vision sights are optical devices that allow observation and aiming in the dark. The devices are mounted on airguns or small arms with a unique mount. Night vision sights can be used for hunting and sport shooting at night and dusk. It is possible to observe at a distance of 400-500 meters (the length depends on the selected model).

A thermal imaging camera is not a night vision device

Many people mistakenly believe that thermal imaging cameras are night vision devices. However, this is different. Even though both technologies are extremely useful in the dark. 

The principle of operation of a thermal imager differs in that, thanks to infrared radiation, the device “collects” information about the thermal spectrum of the environment and displays it in the form of a heat map. It works in complete darkness, and its functionality does not depend on an additional light source. This makes the device very useful in the construction industry, and it is in demand among utility workers, doctors, etc. Their development is also categorized by generation.

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