Night vision or image intensification technology has evolved over various generations. The primary process is a special intra-optical device called an image intensifier tube, which collects ambient light through an optical lens. It then passes it through other electronic components in the device to a screen in the lens. This process is the reason why night vision is green.
Today, night vision is found in everything from security cameras to military binoculars and smartphones. Night vision scopes are not just for the detectives and soldiers but everyone. Every day people make use of night vision scopes for various purposes. Night vision is not just a specific technology but comes in many different forms that can be implemented depending on the scenario.
You must have wondered what night vision is, what night vision looks like, and why night vision is green. Don’t worry; we have answered all your questions.
Why is Night Vision Green?
Night vision is a typical green variant of night vision that you can relate to the military or often see in action movies that talk about using green on purpose. This is because our eyes are more receptive to green than other colors. As far as why night vision scopes are green is concerned, the image intensifier screen is made of phosphor.
This material is used due to the luminous effect; when electrons strike the screen, they glow bright green. The electrons pass through the tube through a plate of microchannels, a disk with millions of microchannels. Upon collision with these microchannels, the voltage surges cause a rapid increase in movement, creating dense electronic clouds that strengthen the original image.
These electrons then collide with a phosphorus-coated screen at the tube’s end. The energy of these electrons produces a greenish image on the screen inside the device. Green color phosphorus is used as the human eye is more sensitive to this color pallet and differentiates shades of green from other color pallets.
Technologies Used in Green Night Vision
To know what makes the night-vision green, we will need to know more about the technology used. These technologies are used in eyewear, as well as in night vision scopes. They are necessary for the appearance of the green vision.
These technologies are thermal imaging, active illumination, and image intensification.
Thermal imaging allows you to compare the thermal signature of an object with its surrounding atmosphere. It can determine when the temperature of the target differs from other objects in its surroundings.
Thermal cameras detect heat emitted from a different object, where they can see infrared light. The heat causes photons to emit in the infrared or infrared spectrum, and although humans cannot see infrared light, these special cameras benefit in different ways.
Though thermal imaging looks like something used in military applications, the lighting is straightforward. The image intensifier used by spectacles or other devices may require more light input to process and display the image when you view it.
The lighting is very close to the infrared range. By increasing the environment’s illumination, the devices create better conditions for the night vision system to take advantage and convert it into an image.
Image intensification is the technology responsible for the green image you see through night vision scopes, goggles, or other similar devices. This technology is intended to see you in the dark. Image improvement works by sensing low levels of light and strengthening it.
When the photons, tiny particles of light, go through the image enhancer, they first collide with a particular layer that releases the electrons. These electrons then hit the microchannel plate, which doubles the electrons before they hit the glowing screen.
Why Only Green Night Vision?
Despite the darkness, photons hitting the lens that forms the front of night vision scopes still carries all colors’ light. However, the problem is that there is no other way to keep this information when the photocathode converts it to electrons. Thus, this color information is effectively converted to black and white.
They can spot things that are difficult to see with an ordinary image intensifier. Considering thermal imaging, some of the cameras can create their own infrared light in a process called active lighting that illuminates the environment with infrared radiation. Since this extra infrared energy is reflected regardless of the camera’s target for this strategy, it will give high-resolution images.
Phosphors in night vision goggles are intentionally designed to make green images for several simple but effective reasons:
- The human eye is most sensitive to wavelengths of light of around 555 nm, which turn green.
- It is convenient and easier for people to watch a green screen for much longer than watching a black and white screen.
- Therefore, night vision goggles tend to turn green because, in this wavelength, the natural night vision of the human eye is enhanced.
Is it Legal to Own Night Vision Scopes?
Yes, it is legal to own night vision scopes. Citizens can own and use night vision scopes. However, taking these devices out of the country is illegal.
Do Night Vision Goggles Work in Complete Darkness?
It is a common question do night vision scopes work in complete darkness. Yes, most of the night vision scopes work in complete darkness. You must do proper research before buying one according to your requirements and usage.
Does Night Vision Need Light?
No, night vision doesn’t need light. The night vision technology can work in the darkest of nights because it works by detecting thermal radiations.
The human eye is very sensitive to light in all its colors. However, it can differentiate green shades when compared to other colors. Considering why night vision is green, the main reason that night vision is green is that the screen used to intensify the image inside the device is mainly made up of phosphors.