With the image intensifier as the core device, the night external aiming device does not use infrared searchlight to illuminate the target when working, but USES the reflected light of the target under weak light to observe and aim the target by enhancing the visible image that can be felt by human eyes through the image intensifier on the screen.Infrared night vision instrument is a military night vision instrument using photoelectric conversion technology.It is divided into active mode and passive mode. The former USES infrared searchlight to illuminate the target, and receives reflected infrared radiation to form an image.The latter does not emit infrared rays and relies on the infrared radiation of the target itself to form a "thermal image", hence it is also called a "thermal image instrument".