Light is necessary for human vision. In activities for living.
With the limit that we have the sun as a light source in the daytime, human beings have invented a light source to replace in the form of candles and various lamps for night vision
But some specific activities for that special purpose , Can not use light during operation.
The villain at night will immediately realize and escape. If the police use a flashlight to search Or the military army uses a flashlight for reconnaissance, which will make the enemy aware and will certainly be targeted by enemy ambushes
The limitation that we need to see in the dark, causing the development of night vision technology to be a device that allows us to see at night or at low light, called night vision device.
How Night Vision Works
In night vision systems, the objective lens collects light that you cannot see with your naked eye and focuses it on the image intensifier. Inside the image intensifier a photocathode absorbs this light energy and converts it into electrons.
When this highly intensified electron image strikes the phosphor screen, it causes the screen to emit light that you can see. Since the phosphor screen emits this light in exactly the same pattern and degrees of intensity as the light that is collected by the objective lens, the bright night-time image you see in the eyepiece corresponds precisely to the outside scene you are viewing.