In warfare’s history, soldiers who undertook nocturnal operations always had to use artificial lighting, such as searchlights and other light sources. Using artificial illumination in battle always came with the disadvantage of giving away tactical maneuvers and positions. This changed midway during the last century, when new technologies introduced the concept of night vision in modern warfare. Military night vision binoculars, goggles, and other tools that did not need other sources of light to enable the user to see in the dark were used.

With the integration of night vision, these and other devices gave soldiers the capacity to scout, maneuver, or fight at night and other times when visibility is low. Army scientists and engineers developed methods to harness ambient electromagnetic radiation (otherwise invisible to the naked eye) and incorporate these into devices that enabled soldiers to fight at night as well as they would in broad daylight.

There are different types of night vision devices – thermals and image intensifiers. Thermal night vision devices operate by sensing the variance in temperature between the environment and an object, and give the user an image based on the findings. Detector technology such as Thermal FLIR, or Forward-Looking Infrared, is used, and mostly installed in helicopters, tanks, and other vehicles used in combat. Image-intensifier binoculars, as the name suggests, work by amplifying available light, which means that these will not work in total and absolute darkness. However, devices with image intensifiers can operate by significantly amplifying what little light is present from two thousand to five thousand times.

Night vision goggles are similar in structure to night vision binoculars. Mainly, night vision goggles are devices that work on the premise of electro-optical technology, intensifying ambient light as opposed to working with their own light sources. The light is electronically amplified to show an image of a soldier’s surroundings through a phosphor display screen. Typically, night vision binoculars use light from distant sources, such as buildings, faraway cities, or the moon and stars. As these tools are hypersensitive to a large portion of the invisible and visible light spectrum, any amount of illumination can be amplified and turned into an electronic image on the phosphor screen.

Available light passes through the night vision binoculars, starting with the lens, and enters the device. The light then hits a photographic cathode that the binoculars’ battery powers with a charge. The charge of energy speeds through the vacuum of the image intensifier and encounters the phosphor display, which hosts the focused image. The eyepiece enlarges this image for the user to see.

The color green is used for the phosphor display screen as the human eye can identify the largest number of hues in that color. Night vision binoculars also have the ability to magnify an image in different ranges. The strength of magnification of the lens, as well as that of the image intensifier, contributes to the power of a night vision device. The most powerful military night vision binoculars can view objects at a maximum of 400 feet.

Soldiers use night vision binoculars due to their portability given to these devices because of their relatively small energy requirements, compact size, and light weight. Research and development teams from many countries continue to hone night vision technology for better sensitivity, larger resolution, increased viewing image size, and longer spectral response to wavelength.