Why is Night Vision Green?

Night vision devicesNight vision devices

Let us dive into the depths of the history of the creation of night vision devices. Why is green so attractive to humans? When looking at the greenish glow of night vision screens, fireflies, ocean waves glowing with a greenish glow, green mysterious alien creatures come to mind. It is undeniable that the flickering green light evokes pleasant associations and is quite beautiful. In theory, green is one of the most common colors on Earth, with many shades. Our vision is naturally adapted to distinguish many nuances of green. And this number of options is much greater for green than for any other color. Green is in the middle of the light range that a person can distinguish. Our vision is not stressed when viewing green images; on the contrary, we are calm and ready to explore. This is what you need for a long observation in night vision goggles. The choice of green was not accidental; it was based on the natural abilities of our vision and contributed to our productivity.

Who and When Invented Night Vision?

The first to build a working night vision device was the Dutch scientists Holst and de Boer. The idea was nurtured in 1928 but was realized only in 1934 in the Philips laboratory in the Netherlands. This installation was called “Holst’s Glass,” and the principle of its operation formed the basis for subsequent inventions.

The war was approaching, and German engineers from the company Allgemeine Electrical Cicitats-Gesellschaft 1936 began the production of night vision devices on an industrial scale for the needs of the army. The prototype entered service in 1939 for use on the Pak 35/36 L/45 anti-tank guns.

In the same year, the famous physicist Kalman Tihanyi created an electronic television camera for the air defense of the British army that captures infrared radiation. This helped to detect German planes making monstrous raids on London in 1940. Parts of the future night vision device gradually took shape, and the war spurred inventors from all countries to modify and improve prototypes.

By 1943 the Sparrow Hawk system was equipped with an IR searchlight and installed on German Panther tanks. The German infantry received an IF Vampir lantern with a battery to illuminate enemy troops in night assaults. At that time, it was a revolutionary weapon that gave an undeniable advantage in night combat.

American scientists created the first Gen 0 night vision devices during World War II. The M1-M3 sights proved quite good and were used in the battle with Japan and Korea. But their use was not massive; instead, they were single operations.

But there is no doubt that at the time of the Second World War, the palm in development belonged to the Germans. Already by 1944. the German Pak 40 gun could conduct aimed fire in the dark at 400m. The following achievement was the infrared vision device Sperber FG 1250. They illuminated Soviet tanks at a distance of 700m. and contributed to the German tank troops’ offensive in ​​Lake Balaton. Despite their success, the devices had drawbacks – they were susceptible to light and were bulky and heavy. They had to be transported in tanks or trucks, depriving them of mobility.

From this point of view, the American night vision sights, used in the 1960s in the Vietnam War, made a real breakthrough in the history of night vision. They were mobile and provided many advantages for tactical night operations. This was the moment Gen1 was born. But on the other hand, the sight worked only on very bright nights or gave out the sniper head on the beam of the IR flashlight. For dominance in the night, this was not enough. Subsequent Gen 2s could already do without backlighting and were an order of magnitude lighter and more compact. The creation of Gen 2 fell in the 1970s. Image quality requirements grew, and generation 2+ appeared.

The American scientific potential gained momentum and led the market for night vision devices. In 2000 appeared Gem 3, 3+, which are in service with the American army to this day. In addition to the usual green phosphorus, white phosphorus has been widely used. But progress does not stand still, and today the American armed forces are testing the 4th generation of night vision devices equipped with white phosphorus.

What about the Green Vision?

Green vision is traditional and already familiar to most people. The production technology of green phosphor screens is simple. The screen is placed in a solution with phosphorus, and its particles are allowed to settle on the surface, with a layer of up to 8 microns. Then, a thin layer of aluminum is applied in a chamber with an inert gas argon, giving the screen good conductivity. Next, the screen is removed and dried.

The main characteristics of the screen are fluorescence and phosphorescence. Fluorescence is responsible for the brightness of the screen. Phosphorescence indicates how long the screen will glow. The mechanism for changing the picture assumes we will have time to consider it. Still, the following image will appear quickly enough so that there is no effect of motion deceleration. Typically, this entire process takes up to 1 millisecond. You can think of this value as the frequency of screen changes.

The glow’s brightness depends on the coating’s quality and the flow of electrons that bombard the surface of the phosphor. The more intense the flow of electrons, the more the screen glows. Thus, objects with a larger surface area will be more visible and will cause the screen to burn more. The difference in the degree of illumination of objects allows the operator to navigate in the dark and correctly determine the distance between them.

We would focus less on on-screen color today. The color of the screen can be anything. There is white, yellow, red, and black phosphorus in nature. Theoretically, the net can glow yellow, green, white, pink, purple, and crimson. Individual preferences of people should not be discounted. According to studies, a small part of the population may experience discomfort or headaches when watching a green screen for a long time. In addition, remember people with impaired color perception. Among them, there are the military, rescuers, and policemen. Their duties include contact with night vision goggles or night vision binoculars. From this point of view, the grayish scale of white phosphorus will be more comfortable for them.

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If you look at the financial side of the issue, green phosphorus is more affordable than white phosphorus. We wouldn’t be in an endless race for the year’s hottest and most expensive model. This is a pointless exercise. It is not a fact that the expectations will justify themselves and can justify the amount that will have to be paid. It is better to take the slow path of analyzing your needs, collecting information, and personally evaluating several models. No specialist knows all your needs and cannot assess your comfort. Choose wisely and enjoy.

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