Buzz
The green tint seen in night vision devices is intentional for several reasons. Initially, manufacturers tested various colors and discovered that the different shades forming the monochrome night vision image are most clearly visible and distinguishable when they are green. In other words, while night vision scenes in movies like Silence of the Lambs or in Call of Duty may appear somewhat unrealistic, the green hue offers the most precise and practical image for the user. Additionally, since the human eye is most sensitive to light wavelengths around 555 nanometers—essentially green—the display can be dimmed slightly, conserving battery life.
Who was the inventor of night vision?
The first functional night vision technology was developed in Germany during the mid-1930s, with these devices being utilized by both German tanks and infantry in World War II. At the same time, U.S. military scientists created their own night vision systems, which were first used in World War II and later in the Korean War.
These 'Generation 0' devices used active infrared technology to enhance visibility. Soldiers carried an IR illuminator, which emitted a near-infrared light beam. This light would reflect off objects and return to the scope’s lens, forming a visible image of the surroundings. The German Nachtjägers, or 'night hunters,' used illuminators roughly the size of dinner plates, powered by large supply packs carried on the soldiers’ backs.
Technology progressed significantly in the following decades, and by the time the U.S. entered the Vietnam War, many soldiers were equipped with passive 'starlight scopes.' These scopes employed image-intensifying tubes that amplified ambient light—primarily from the moon and stars, which explains the name—and created electronic images of dark areas.
'Generation 1' technology is still in use today in more affordable consumer-grade night vision equipment. While military and law enforcement have transitioned to newer generations with advanced features over time, image-intensifying night vision—often seen in movies and games—is still based on the same fundamental principles as these early models. There's also thermal imaging, a different type of technology.
I Can See Clearly Now
The lenses at the front of a night vision scope or goggles capture available light, including some infrared light from the lower spectrum. This light is focused on a photocathode within the image intensifier tube, where photons (light particles) are converted into electrons.
As the electrons travel through the tube, they pass through a microchannel plate, which is a disc with millions of tiny holes, or microchannels. When the electrons collide with the electrodes inside the microchannels, bursts of voltage cause the electron movement to accelerate rapidly, creating dense clouds of electrons that amplify the original image.
At the end of the tube, the electrons strike a phosphor-coated screen, a material that emits visible light when energized. (We discussed phosphors earlier with glow-in-the-dark toys.) The electrons energize the phosphor, converting them back into photons. These photons align with the original photons that entered the tube, creating the greenish image displayed on the screen inside the viewing lens of the device.
