A night vision camera is a device which when used during night, low light conditions or even in the absence of light can produces a clear image. They find huge application in the security system for surveillance purpose. Primarily invented for military they are expanding their use in commercial and household security system as well. Every Night Vision device is actually a combination of a number of devices that work on different technologies. At the very beginning, we have a front lens that actually takes up whatever amount of light that is there in the environment. Following the front lens is the photocathode which forms over 3/4th costs of the device.
Now, photocathode is an intensifier that gives more brightness to every component of the light rays captured. Following the photocathode is the closely placed Micro Channel Plate (MCP). MCP detects electrons at various frequencies of light and constructs a charge pulse for every photon that strikes it. Hence, use of an MCP makes detection of the weakest component of light possible that further proves to be a boon for light amplification. Next to it is the high voltage power supply which, as its name says, provides power supply to the device. A phosphorous screen is attached before the eye screen which is responsible for the green image that is formed. Due to various chemical and physical processes that happen inside the device, electrons fall off the visible region of light. The phosphorous lens tunes the frequencies of these electrons into the visible region and hence a proper image is then transmitted to the eye piece. Read more about night vision technology.
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