How Do Night Vision Binoculars Work?
For a long time, everyone referred to night vision devices as infrared devices. They’ve been a staple of spy movies and video games. Not everyone understands just how common night vision is these days. Fewer still understand the basics of how it works and why there are so many optical gadgets that use it.
Night vision binoculars, in particular, are not exactly what they seem. They sound straightforward but the intricacies of their design make them quite different in concept and applications than regular binoculars.
Here’s what you need to know about the differences between regular binoculars and night vision models used by civilians and military personnel.
Binoculars use light refraction to allow you to view objects from far away. They use a magnification lens and a prism for the ocular components. The prism inverts the image to ensure that what you see is not upside down. The magnification lens is what enlarges the object in the sight.
Although binoculars come in various designs, they all achieve the same results, though some do it better than others. The size of the lenses determines how much light is gathered and thus the brightness of the image.
Night Vision Basics
Night vision refers to the ability to see in low-light conditions, sometimes even pitch-black conditions. The basics of night vision technology revolve around spectral and intensity ranges. The spectral range refers to how much radiation is visible. What we call visible light is just a small portion in the full range of electromagnetic radiation.
An enhanced spectral range would allow us to see near-infrared radiation. But that’s not enough to allow us to see in the dark. We also need a light source. Night vision technology maximizes the amount of detail we can see with minimal intensity range.
When combined with modern technology and optical science, these two imaging techniques allow us to see detailed images of our surroundings in dark environments. Another trick used to enhance the details is using certain phosphors that color the image green. This is because years of testing and medical advancements have proven that human eyes are a lot more receptive to green light.
Night Vision Binoculars
So how do night vision binoculars come into play? Night vision binoculars work just as regular binoculars with an added bonus; they can capture the little light emitted on the lower end of the infrared light spectrum.
When the light is captured by the objective lens, it’s also relayed to an image intensifier. This needs a power source to work, which is why the proper night vision goggles and binoculars require batteries or power banks. During this transfer, the image intensifier converts photons into electrons which cause the atoms in the intensifier to release even more electrons.
The result of this is that thousands of electrons end up hitting a phosphor-coated screen. That’s what releases the photons needed to create the green picture everyone associates with night vision. You see the green image through the ocular lens which is also what makes some levels of magnification possible.
But, true night vision binoculars aren’t as effective as standard binoculars. Most of them can only offer a 6x magnification without losing too much detail. The efficiency has improved over the years. However, the main use is to see in the dark, usually at a closer range and not 1,000 yards away.
Night vision binoculars have similar uses as night vision scopes (not necessarily night vision rifle scopes). They are used by the military and law enforcement officers to gather important intel from a safe distance or from a cover position.
Although binoculars don’t have the same magnification as scopes, they are a lot easier to use. They put less strain on the eyes and provide a wider field of vision. Although initially developed by the military for nighttime combat, these days civilians have just as much access to night vision equipment.
Binoculars are also used by some birdwatchers, hunters and private investigators.
A Final Thought
Night vision binoculars aren’t that complicated to figure out once you know the principles behind the conversion of infrared radiation into visible light for the human eye. Even though they don’t have the magnification potential of regular binoculars, they have a variety of applications for civilians, researchers, and military personnel.
Although technology has advanced tremendously over the years, the principles remain simple. That’s why it’s quite easy to make your own night vision binoculars, goggles, or even camera. You just need the right equipment and basic understanding of light filtering.