Given their name, night vision binoculars might seem to simply be traditional binoculars with a slight technological twist to allow them to function in the evening. Nothing could be further from the truth.
Turning Night To Day
There are three different classifications of night vision binoculars. Each works in a slightly different method, but there is a general process applicable to all night vision devices whether binoculars, sights or other equipment.
Perhaps the most important thing to note immediately is night vision binoculars do not turn dark into light per se. Instead, these devices capture photons from the targeted environment. Photons are often referred to as a form of light, but a better description is to categorize them as a form of electromagnetic radiation. Once scientists started treating them as such, major breakthroughs were made in night vision technology.
Once photons are taken into the binocular, they strike a tiny photoelectric plate. The plate is charged with electricity. When the photons strike the plate, the plate kicks off electrons that travel further into the binoculars. At this point, the electrons are passed through a multiplier. As the name suggests, the multiplier creates multiples of each electron while also speeding them up as they move down the lens tube.
The electrons next strike a phosphor covered plate. The collision causes the phosphor to release a particle element for each electron. The particle is light, but in a greenish hue. An image is created as the volume of electrons strike the phosphor which the user then sees as a visible image.
If it seems as though the image produced would be rather diffuse…it is. The first night vision binoculars were excellent in the sense the user could see what objects were around them, but less than stellar when it came to any specifics regarding those objects. Modern night vision binoculars provide much sharper images thanks to improved technology. The new technology is extremely complex and most companies refuse to release any information on it. At its core, however, the night vision process still works as described above.
Types of Night Vision Binoculars
There are actually three types of night vision binocular available. The types are broken down by how they function in certain light conditions.
Passive night vision binoculars work best in conditions where there is an independent light source. For example, these binoculars work well in a city environment where there is some ambient light from various sources such as windows and store signs.
Passive binoculars work by using large lenses to capture whatever light possible. This light is then focused into a smaller area to create an image the eye can see. The image tends to be distinct, but not particularly sharp. One might be able to tell a dog is standing on the lawn and the size of dog, but not much else. If no light is present, these binoculars will not work.
Active night vision binoculars can work in much darker conditions when compared to passive devices. These binoculars seek to capture any light available and then actively process the light to build a fuller, more detailed picture of the target area for the person using the device. Many active binoculars provide a clearer image than the human eye produces for the brain according to testing.
Active binoculars are also powered devices. Electricity is needed to significantly multiply and speed up the photons used in the night vision process. The energy needs are very high, so it is important for users to make sure their night vision binoculars are fully charged before using them. Nothing is worse then being far down a trail in the middle of the night and suddenly going “blind.”
Infrared night vision binoculars are the best of the best. As the name suggests, these binoculars collect infrared input from the scenery surrounding the user and then converts the information to an image the user can view. The human eye cannot see infrared light, but this form of light tends to be clearer and more detailed in the evening. As a result, these binoculars produced the clearest, most detailed images of any night vision binoculars. Since they do not rely on “white light”, they also work in complete darkness.
Selecting the correct pair of night vision binoculars is highly dependent on the intended need. If the binoculars are to be used in areas with plenty of light, any of the three types will work fine. If the intended use is in a very dark area, then either the active or infrared binoculars are the better choice.
Night vision technology has truly come a long way from the days of blurry, muddled images. The fact night vision binoculars can produce images sharper than those produced by the human eye tells you pretty much everything you need to know.