Protective measures for safe use of low-light night vision devices

In terms of design, low-light night vision devices will use physical methods or photoelectric control methods to prevent low-light image intensifiers from burning out. These are passive protection methods.

The physical method is to design a light hole (i.e. pinhole) with a diameter of 1mm on the hood. In a room with lighting during the day or night, the light energy entering the low-light night vision device through the pinhole is sufficient to meet its normal working conditions. In addition, the pinhole is also to meet the needs of checking the working status of low-light night vision devices before combat. Never open the hood and turn on the power in a room with lighting during the day or night, so that the low-light night vision device is in a strong light working state. Otherwise, the image intensifier of the low-light night vision device will be burned.

The photoelectric control method is to install a photoelectric sensor in the direct viewing direction of the low-light night vision device. When the total average external light intensity is greater than 1 lux, the working circuit of the low-light night vision device will automatically shut down. However, this method also has flaws. For example, the total average illumination intensity of long-distance point light sources and surface light sources is less than 1 lux, which will not trigger the photoelectric sensor to shut down the working circuit of the low-light night vision device. Looking directly at this light source will cause low light. Partial burnout of the night vision device image intensifier.

None of the above methods can completely and completely provide effective protection in actual use and operation. Only by being fully familiar with and understanding the correct use of low-light night vision devices, mastering relevant knowledge, and adopting human-initiated protection methods can we The most fundamental solution.

Since the invention of low-light night vision devices, there has been a problem that the image intensifier is easily burned and damaged during use. Since the image intensifier is used in a light intensity of 0.001 lux to 1 lux, early image intensifiers will burn out if they are not turned off in time when illuminated by flares or car headlights. Nowadays, second-generation image intensifiers and above have a short-term strong light automatic protection function, but this function cannot prevent local point and surface light sources from burning the cathode surface of the image intensifier, such as distant street lights or close-up lights in the dark. The energy generated by LED indicators at a distance is not enough to activate the image intensifier protection circuit, but these light sources are imaged as small light energy concentration points on the cathode surface, that is, light stress points. If the light stress point remains on the cathode surface for more than 2 minutes, the local temperature of the cathode surface will exceed 200°C, causing local irreversible burning of the image intensifier and forming dark spots or dark spots. This principle is the same as that a convex lens can burn through paper. As we all know, if you use a convex lens to focus sunlight on a piece of white paper and keep it motionless, a small hole will be burned out of the white paper by the light stress after 2 to 5 minutes. And if you keep moving the white paper so that the focus point does not stay at the fixed position of the white paper, no holes will be burned in the white paper even for 2 to 3 hours. Therefore, the low-light night vision device will encounter strong points during use. When using a light source, you should change the viewing direction in time to avoid staring at strong light points to avoid damage to the image intensifier.

Taking active human protection is the most effective safety protection measure for low-light night vision devices. Low-light night vision devices will only be burned when they are turned on. Developing good operating habits is an effective measure to reduce and eliminate damage to the image intensifier. Operators must protect low-light night vision devices like intensifiers like the retina of their own eyes. If you suddenly encounter strong light (vehicle lights, street lights, searchlights, flares, gun flames, etc.) at night, you should immediately take three protection methods: rotating the direction of the low-light night vision device, covering the hood in time, or turning off the power of the low-light system. First, prevent the low-light night vision device from staring at a strong light source for too long (2 minutes) to avoid local burns to the cathode surface of the image intensifier.

The operator can turn on the power of the low-light system only after his eyes are in the observation position of the low-light night vision device. When his eyes stop observing or leave the observation position of the low-light night vision device, the power of the low-light system must be turned off. This is because the human eye will feel pain when encountering strong harmful light and will immediately find ways to actively avoid it. However, when the image intensifier burns out, it will be silent. Therefore, it is ensured that the lighting environment of the low-light night vision device is always under the supervision of the human eye (that is, the combination of human and mirror). Only by keeping this principle in mind can we most effectively and proactively prevent the image intensifier of the low-light night vision device from being burned.

When using a laser calibration scope to calibrate the gun at night (the laser will produce a bright spot on the calibration target), the calibration target must be 100m away, and the calibration work should be completed within 2 minutes. If it cannot be completed, the power of the low-light night vision device should be turned off for 5 minutes, and then the gun should be calibrated again for 2 minutes, in sequence. This can reduce light stress and avoid local burns to the cathode surface of the image intensifier.

When the low-light night vision device is not used for a long time, the battery should be removed to prevent battery leakage and damage to the product. At the same time, power on for at least 10 minutes every three months will help extend the service life of the product.

• Previous: How low-light night vision devices work and the difference between green and white images
• Next: How to use low-light night vision device