Questions and answers about night vision devices
Night vision devices, also known as night vision glasses, night vision binoculars, and infrared binoculars, are an instrument for observing at night in complete darkness or with dim light, and were first used in military affairs. Later, it is widely used in criminal investigation, safety protection, forest fire prevention, power and communication line inspection, construction site, farm, farm care, and even tourism and other fields. Night vision devices have been developed for half a century and can be roughly divided into several types:
1. Low-light night vision technology, also known as image intensification technology, is a photoelectric imaging technology that enhances the target image under weak light irradiation through night vision goggles with image intensifier tubes for observation. Low-light night vision device is currently the night vision equipment with the largest production volume and the most widely used abroad. It can be divided into two types: direct observation and indirect observation.
2. Infrared night vision technology is divided into active and passive. Active infrared night vision technology is a night vision technology that implements observation by actively illuminating and using the infrared light reflected by the target to reflect the infrared source. The corresponding equipment is an active infrared night vision device. Although the active infrared night vision technology has the characteristics of clear imaging and simple production, it also has a fatal weakness: on the battlefield, the infrared light of the infrared light will be detected by the enemy's infrared detection device. This weakness undoubtedly declared the fate of active infrared night vision technology to be eliminated. Passive infrared night vision technology is an infrared technology that realizes observation by means of infrared radiation emitted by the target itself. Simply put, it is to image according to different temperatures. The resolution is very low, but it has its special purpose.
3. Some night vision devices have improved the semiconductor material of the photocathode, which makes them sensitive to low light and infrared. The infrared night vision device and the low light night vision device are unified on one instrument, and the low light night vision can be played at night on a sunny day. It can be used as an active infrared night vision device by emitting infrared rays at night in rainy and foggy days, and the working distance is farther than that of a simple passive low-light night vision device.
Questions and answers about night vision goggles:
1. What is the difference between night vision goggles and binoculars?
Answer: The telescope is an optical instrument that directly uses the lens to magnify the viewing angle of the object on the retina. It does not use a power supply and cannot be viewed in a dark or low-light environment; the night vision device is an instrument that uses the principle of image enhancement or infrared imaging to observe , the clarity is not as good as a telescope, but it is suitable for viewing in total darkness or starlight and moonlight environments.
2. Can the night vision device be used during the day?
Answer: No, and it is not necessary. Do not open the lens cover and power at the same time during the day or under strong light, otherwise the core components of the night vision device will be damaged after a long time.
3. Can infrared rays be seen directly with the naked eye?
Answer: Infrared rays are outside the visible light band and cannot be seen directly with the naked eye, so it doesn't matter what color it is. Can night vision goggles distinguish colors?
Answer: No. The imaging of the night vision device is generally yellow-green, which cannot reflect the true color of the object.
4. Why are active night vision devices suitable for civilian use?
Answer: The night vision device with active function has an infrared lamp, which emits a beam of infrared light to illuminate the scene. Therefore, the imaging is clear, but the infrared light emitted actively is easily detected by the enemy's instruments and exposes the target, so it is eliminated in the military, but there is no problem of exposure for civilian use, so the disadvantages become advantages, plus the price Inexpensive, so night vision goggles with active infrared are suitable for civilian use.
