Why do night vision gadgets fear bright lights?
There are various types of night vision devices, but they are basically composed of optical systems, image converters 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 converter tube or low light level tube is the "heart" of the night vision device. Imager tubes can transform invisible infrared images into visible ones, while low light tubes can enhance weak light by tens of thousands or even hundreds of thousands of times, making it visible to the human eye.
Night vision devices are afraid of strong light because the image converter and low light level tube are afraid of strong light. Taking the image converter as an example, when infrared light illuminates the photocathode of the image converter, the photocathode emits electrons. Under the action of a high voltage field (16-21 kV) and an electron lens, the electrons accelerate towards the fluorescent screen, causing it to display a visible target image. The image converter receives more light signals, emits more electrons, and the light signal emitted by the fluorescent screen is stronger, resulting in a brighter image. They are basically proportional. But if the external light is too strong, the number of electrons emitted by the photocathode will not increase to a certain extent, that is, saturation will occur, and the target will not be visible clearly. If too strong light suddenly shoots over, it may also cause the photocathode of the tube to burn out and cannot emit electrons, of course, nothing can be seen.
Although night vision devices have taken certain measures to prevent strong light, their effectiveness is limited, so they must be operated strictly according to regulations when used. When encountering strong light or correcting targets during the day, it is necessary to put on the objective lens cover or turn off the power switch. The correct use of night vision devices can extend their service life and avoid unnecessary damage, thus fully exerting the function of night vision devices.
Purchasing infrared night vision equipment
1. Image intensifier: What generation is it. Be sure to confirm with the merchant when buying. Because the packaging and instructions of night vision devices generally do not indicate which generation of image intensifiers they are. Of course, if you want to buy a second-generation or third-generation night vision device, it's better to buy a night vision device with a clear indication of which generation of image intensifier is used to avoid infringement of your rights. At present, the market, such as RHO's night vision devices in Russia, indicate on the product packaging and machine which generation of image intensifier tubes are used.
2. Lens: Check the lens aperture and magnification. Without considering volume, of course, the larger the better. In the same case of an image intensifier, the principle is that the larger the aperture, the farther the observation distance, and the clearer the image.
3. Image enhancement technology: Generally, night vision devices equipped with this technology will have better image brightness and clarity under the same conditions.
Infrared transmitter: The quality of this performance directly affects the imaging quality.
5. Resolution: The resolution of the lens is very important, as the higher the resolution, the clearer the displayed image.
