How to select the appropriate night vision device?

First night vision device was designed in 1926. That technology was applied to military equipment only. First combat night vision devices were used by German army during the Second World War. Nowadays night vision devices are standard equipment of virtually any army around the world. The development of technology and lower prices caused increase of availability on the civil market. Night vision devices are widely used by the emergency services, security guards as well as amateurs, such as hunters, outdoor games' lovers (e.g. ASG, paintball, survival, etc.) and other users who need equipment specially designed for facilitating observation and moving around in the dark.

How a night vision device works?

A night vision device is an optoelectronic system based on a light converter which amplifies residual light from a few to dozens of times, by generating image visible to the human eye. It's worth remembering that night vision devices, in order to work properly, need a minimal amount of external light, such as moonlight, starlight or residual light from other light sources. Even the very remote ones, or light generated by a IR illuminator mixed with the night vision device (most night vision devices are equipped with build-in short-range IR lamps mated with special illuminators of very high power and wide range as well as light-intensity adjustment and infrared light beam focus adjustment).

The residual light falls through the specially adjusted lens designed to focus the dispersed light. The beam of electrons which falls on the photocathode (an optoelectronical system which emits electrons when exposed to the light). The beam of electrons is subsequently amplified many timesand redirected on a phosphor screen (a luminophore) designed to transform the beam of electrons into the beam of photons, and thus generates the visible image in the eyepiece. Phosphorous, covering the luminophore, emits green light due to the fact that the sensitivity of human eye is the highest in that particular band. Human eye recognizes a multitude of hues in the 500-560 nm band which corresponds to the green and blue. This band makes it possible to recognize a lot more details than in the case of other colours.

What to remember when using a night vision device?

Modern night vision devices are durable and can be used for many years. Properly used night vision device can work for as long as few thousand hours before first signs of lamp malfunction. This is completely normal that the lamp's luminophore gradually burns out. After working properly for some time, the device starts to generate gradually darker and darker image.

The proper operationof a night vision device and protecting it from a strong direct light is a paramount issue. Intensive light causes rapid burn-out of the luminophore and, in some cases, even an instant failure. Short-time illumination causes gradual lamp malfunction, image darkening and appearance of dark spots. It is important to remember about few short rules:

It is completely normal to see dark spots in the night vision image. This is a result of the lamp's imperfection and is noticeable even in case of the new devices. Spots don't affect neither the image quality nor the functionality of the device.

What is the range of a night vision device?

The range of a night vision device depends on many factors. The amount of residual light and type of landform are of the most importance. A night vision device behaves differently during a bright moon night than during a cloudy night. A snowy clearing provides far better visibility than a thick forest covered by a layer of decayed leaves, which absorb great amounts of light. In case of total darkness the range depends completely on the artificial IR illumination source. Most night vision devices are equipped with a built-in short-range illuminator providing good visibility in a 20-30 m range. Moreover, the night vision device can be also assisted by an external long-range illuminator. It can be a torch emitting near infrared light and equipped with a power adjustment and a light beam focus. Depending on a variety of conditions, it can illuminate the terrain in a 100-400 m range.

It is also important to differentiate between detection range (a distance small enough to detect an object) and recognition range (a distance small enough to distinguish the details and differentiate between a man and a tree trunk). However, both ranges strongly depend on the size of the object. It is certainly easier to spot a roe deer than a fox. The model of lens and its magnification are also important parameters. Night vision devices with a lens magnification from 1x to 8x are widely available on the market. The stronger the magnification the greater the range of a device. Generally, it can be estimated that I/I+ generation devices make it possible to detect a man from 30 to 150 m whereas II/II+ generation devices offer three times greater range (from 150 to 600 m).

What are the generations of night vision devices?

Depending on the quality of an image amplifier and applied technologies, night vision devices can be separated into classes called generations. This is a very rough division but it makes it possible to unambiguously assign a device to a particular image quality.

Generation I – the most popular and the cheapest class of night vision devices provides relatively bright and clear image, without adding too much to production costs. Image amplifiers in this class of devices offer about 1000-5000 times light amplification. Nowadays, I+ devices are the most common class due to their higher image resolution, higher sensitivity and smaller image distortion. This type of night vision devices is sufficient for most of the less-demanding tasks, such as sailing, wildlife watching, outdoor games or surveillance of a protected area of lesser importance. The low cost is the biggest advantage here.

Generation II – is a great leap forward when it comes to quality due to insertion of an additional microchannel plate (MCP) between the photocathode and the intensifier tube. Physical phenomena occurring in the MCP cause electron multiplication in the electric field. It is made of glass covered with holes of very small diameter which are positioned at a specially adjusted angle. Due to metallization of external surfaces polarized with a voltage of 100-200V and unparalleled channel positioning each electron collides with the walls (from 3 to 8 times when passing through the plate) and causes subsequent emission of 2-4 secondary electrons. This solution makes the image intensifier a way better than the I generation (up to 50000 times better intensification) and contributes to the image brightness and detail. Its main disadvantage is a considerably higher production cost resulting from the necessity to install additional converter, which rotates the image by 180°. There is also a II+ class characterized by better image parameters (reduced distortion) and lower power consumption. Due to considerably higher price this type of night vision devices is used mainly by professionals (army, police, border guard or forest guards) for surveillance of important buildings or by hunters for detecting the wildlife.

Generation III and IV – the most modern night vision device generations which are freely available on the European civil market. Generation III are virtually II/II+ devices with improved resolution and lifespan. The difference between class III and II is considerably smaller than that between the II and the I generation. Generation IV is used rarely due to its very short lifespan (it is in a prototype phase). The simplest model can be purchased for less than 20

CORE™ (Ceramic Optical Ruggedized Engine) – is an original technology designed by Armasight. The image intensifier is made from ceramic mixed with metal alloys, like in case of II / II+ generation, but without MCP. This solution combines the main advantage of I generation (i.e. affordable price) with the image quality of higher models. Its main features include: improved light intensification coefficient, high sensitivity and very high image resolution, which is even higher than in case of II / II+ devices. Blur and other image distortion plaguing cheaper models were also eliminated. Due to their ceramic core CORE™ night vision devices are more resistant to mechanical damage than devices based on glass components.

Digital night vision devices – works on a completely different principle than the models mentioned earlier. They have no photocathode, intensifier tube or phosphorous lamp. These components were replaced by a digital light-sensitive CCD matrix (similar to matrices used in digital cameras or video cameras). The image from the matrix is digitally processed and displayed on a LCD placed in the device's eyepiece. When it comes to quality and sensitivity, good digital night vision devices can be placed between I and II generation. Additionally, they offer a variety of unique functions, such as colour palette adjustment, brightness and contrast adjustment or displaying additional information on the LCD screen (e.g. reticle). Their main advantage is a virtually unlimited converter's lifespan and insensitivity to bright light.

Which kind of night vision device is right for you?

Both I and II generation of night vision devices can have a variety of forms. There are scopes, binocular, google with head or helmet mount, gunsight and night vision devices designed to be mounted directly on a firearm. It is important to give some thought to a form and its key features when choosing the proper model of a night vision device.

Google or monocular with a head mount are perfectly suited for tactical purposes (in both professional army and amateur paintball club) due to being lightweight and freeing user's hands. It is advisable to choose a model with 1x zoom and wide field of view in order to aid the sense of direction. Good choices are gen. I Vega or Ninox night vision device with a head mount, Spark or double google Spark-X based on CORE™ technology or gen. II Sirius (there are optional head and helmet mounts for these models). Google Nyx7 are also a perfect solution.

Night vision monoculars and binoculars with a 3 to 5x magnification are best suited for hunting and surveillance. They provide long recognition range without sacrificing wide field of view. II generation devices, such as Avenger (stable optical system and 3x zoom) or Discovery binocular (with 3x, 5x and 8x lens), are generally recommended for this purpose. Spark B binocular based on CORE™ technology is also a good choice.

Digital night vision devices are recommended for security guards carrying out a patrol of an area. Due to their insensitivity to light they are best suited for areas with sources of dynamically changing artificial light. Armasight Prime DC 4x is an example of such a night vision device or more advanced models - Bit and Janus. Just like II generation binoculars and scopes, it can be also used for surveillance of important buildings.

Very often night vision devices are used for shooting after dark. Not only army, police and other law enforcement services but also hunters and sport shooters regularly mount night vision devices on a gun. There are several possibilities when it comes to the choice of the right model. The most recommended solution is to attach special clip-on system to a regular daylight scope. This type of night vision device is easy and fast to install due to a special adapter. There is no need to adjust aiming system once again or even to change the distance between a scope and an eye. CO-MR is an example of such a device. It is perfectly adapted to cooperate with middle-range scopes with 7-6x zoom. We also offer some innovative solutions, such as digital night vision rifle scope Drone Pro. This advanced device is equipped with an optical system with 5x magnification which can be doubled after connecting a teleconverter. Due to digital technology, the user can easily calibrate the device, choose the type of reticle or even connect an optional video recorder to the signal output.

Simple low-budget solutions are best suited for amateur applications, such as hiking, camping or wildlife observation after dusk. Prime model is an example of such a device. Its main features are: meticulous design, good technical parameters and compact waterproof casing. There are two versions available – with 3x and 5x magnification (both with glass optical system). Built-in IR illuminator makes it possible to work in any conditions.

Nowadays everyone can purchase a night vision device. These devices become more and more available. On the market there is a wide variety of night vision devices suited for individual needs. Armasight is a USA company founded by a group of enthusiasts and experts possessing enormous experience. Products of this brand are known for their very good quality of workmanship and great technical parameters. Thanks to practical designe, every client can choose from a variety of different models and be sure to find a solution best for his needs.