How Do Night Vision Goggles Work?

!±8± How Do Night Vision Goggles Work?

Ever wonder how do night vision goggles work? How are they different from your daytime binoculars? Why it is always green color using night vision goggles? In this article, I will explain the inner working of night vision googles.

The Image Intensifier Tube

Night vision is only made possible because of the invention of the image intensifier tube which can amplify very small quantities of light. The image intensifier is basically a vacuum tube that converts photons into electrons.

When lights enters an objective lens, it will strike a photo cathode that carries a high energy charge. The energy charge will travel through the image intensifier and converts photons to electrons and strike a phosphor screen where the image is illuminated. The ocular lenses on the night vision goggles helps to focus on the images.

The main reason why night vision goggles images are green is because through studies conducted, it has been found our naked human eye can differentiate more shades of green than any other color.

There are currently 3 generations of night vision goggles on the market from generation 1 to generation 3. Generation 3 night vision goggles are the most advanced with better image resolution and brightness and are considered even better than military grade goggles. Gen 3 night vision goggles uses gallium arsenide photocathode to enable greater viewing distances under much darker environments.

Thermal Imaging Night Vision Goggles

Another type of night vision goggles uses thermal imaging. It makes use of the fact that most objects whether living or non-living emit electro-magnetic radiation or heat. As a result, thermal imagers can pick up these heat signatures and display an electronic imagery.

One advantage of thermal imaging over night vision goggles that uses light intensifier tubes is that it does not rely on any type of ambient light to display images. Therefore, they are used extensively in environments where no light exists such as fog, hazes etc.