What is the principle of night vision?

Summary： If the human eye can feel the infrared rays, then the human eye can directly see the objects in the night. The night vision device uses a nighttime external sight with the intensifier as the core device, and does not use the infrared searchlight to illuminate the target when working, and the light reflected by the target under the weak illumination is enhanced on the screen by the image intensifier to enhance the visible image that can be perceived by the human eye. Observing and aiming at the target military night vision device is a military device that utilizes photoelectric conversion technology. It is divided into active and passive.   For active infrared, it is equivalent to watching something with a flashlight at night. It uses infrared light to illuminate, and then the infrared light reflected from the target is sensed by the detector, and then the detector performs photoelectric conversion. For passive infrared, the principle that the object above zero will radiate energy outward. The target radiates energy, collects it on the detector through an infrared objective, and then the detector performs photoelectric conversion. This type of detector detects the temperature profile. For low-light night vision devices, first of all, it can only be used in low-light environment, that is to say, at least there is light, and it is still invisible for "reaching your fingers." Principle: The natural light reflected by the target is collected by the objective lens onto the detector. The detector converts the photon into electrons and amplifies it. It is like an electron becomes 100 electrons, and then the electron is hit on the phosphor screen to make the phosphor screen emit The light that the eye can observe.

Keywords： What is the principle of night vision?