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

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 the 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 light signals 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 suddenly shot, 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 role is limited, so it should 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. 

Instructions for use of night vision goggles: 

1. Night vision goggles are precision optoelectronic instruments used to observe targets at night and in low light. In order to work under extremely low illumination, the night vision device is equipped with an infrared transmitter.  

2. Night vision goggles cannot be turned on during the day without a protective cover. When checking the working performance of the night vision device in a room with light, it should be carried out when the night vision device is equipped with a mirror cover, and it should not exceed 3 minutes. And the night vision device should not deal with strong light sources, and it is possible for strong light to enter the interior of the night vision device. Damage it or reduce the life of the night vision device. Strong flashes should also be avoided when viewing objects with night vision goggles with mirror caps. When strong light enters the night vision device, its visibility will decrease or even disappear. At this time, the night vision device should be taken away from the strong light source immediately. After 1-2 minutes, the night vision function will resume. Extremely strong light sources can cause damage to the night vision goggles (such as lasting ten seconds during the day)  

3. The night vision device allows strong flash and flicker within 1 minute. The light spot observed in the field of view is not a defect of the night vision device, but is caused by the flicker of an external light source. When the night vision device works in the standard way, there will be no light spots, and the existence of a small number of black spots and bright spots in the field of view of the night vision device is not a quality defect, but meets the quality standards of the night vision device. Night vision goggles cannot be turned on during the day without a protective cover. 

4 After the night vision device is stored in a cold room or transported in winter, it should be kept in a warm room for 5 hours before being used again. 

5. The night vision device is suitable for use at an ambient temperature of -30 degrees to 30 degrees, a relative humidity of 93% at a temperature of 25 degrees, and a local illumination of 5.10ˉ Lux or below.

6. Night vision device working hours. Do not turn on the infrared irradiator:  

---When the temperature is higher than 0 degrees---20 hours 

---When the temperature is minus 30 degrees---3.5 hours 16 hours 

---When the temperature is minus 30 degrees ---2 hours 

The battery should be placed in a warm place (such as chest pocket) before the night vision device works below 10 degrees and is turned on. 

7. Night vision goggles should be kept in a clean place, protected from heavy pressure, mechanical damage, moisture, and solar radiation.