There are many types of infrared night vision devices, but they are basically composed of optical systems, video tubes or low-light tubes, power supplies and power supply systems. Of course, the active infrared night vision device is also equipped with an infrared searchlight, of which the image tube or the low-light tube is the "heart" of the night vision device. The variable image tube can convert invisible infrared images into visible images, and the low-light tube can enhance the weak light by tens of thousands of times or even hundreds of thousands of times, so that the human eye can perceive it.

 

Infrared night vision devices are afraid of strong light because the variable image tube and the low-light tube are afraid of strong light. Taking the video tube as an example, when infrared light irradiates the photocathode of the video tube, the photocathode emits electrons, and the electrons are accelerated to the fluorescent screen under the action of the high voltage field (16-21 kV) and the electron lens, so that the fluorescent screen is accelerated. A visible target image is displayed. The more the light signal received by the video tube, the more electrons it emits, the stronger the light signal emitted by the fluorescent screen, and the brighter the image seen. They are basically proportional. However, if the outside light is too strong, the electrons emitted by the photocathode will not increase to a certain extent, that is, saturation will occur, and the target will not be seen clearly. If too strong light is shot suddenly, the photocathode of the tube may be burned out, and electrons cannot be emitted, and of course nothing can be seen.

 

Although the infrared night vision device has taken certain anti-glare measures, its function is limited, so it must be operated in strict accordance with the regulations. When encountering strong light or target calibration during the day, put on the objective lens cover or turn off the power switch. Correct use of the infrared night vision device can prolong its service life and avoid unnecessary damage, so as to give full play to the role of the infrared night vision device.