Answers to basic knowledge of night vision devices
1. When will you use night vision products?
Used for leisure and entertainment, such as camping, traveling, fishing, boating, or nature observation. Other uses include surveillance, search and rescue, and security purposes.
2. What are the differences between different generations of night vision products?
The main difference is the advancement of booster technology. The first generation uses an intensifier tube to enhance the brightness of the surrounding environment, which can accelerate the flow of electrons to hit the phosphor surface, just like the principle of a TV screen. Generation II devices, on the other hand, added a micro-frequency disk, which increased the number of electrons striking the phosphorous surface, thereby enhancing brightness. Gen III devices add a gallium arsenide photocathode, which produces a higher number of photoelectrons than Gen II. Both the second generation and the third generation have made great progress in increasing brightness, but their prices are relatively expensive, which discourages most customers. The quality of the first generation is good, and its brightening effect can also meet the needs of most ordinary users and many professional users, so it has a market.
3. How does the night vision device work?
Night vision products collect and intensify the existing light by focusing the light on the image intensifier through the eyepiece. Inside the intensifier, a photocathode is "activated" by the light and converts the photon energy into electrons. The electrostatic field inside the device is accelerated and hits the phosphor surface screen (like a green TV screen), forming an image visible to the naked eye. Through the acceleration of electrons, the brightness and image clarity are enhanced.
4. What is the optimal range of the night vision device?
---Approximately within the range of 10-400 feet. *Maximum viewing distance depends on the use environment, such as cloudy weather, fog or rain, etc., will shorten the range of the night vision device. Infrared emitters can increase the range, especially when used in enclosed areas like warehouses, caves, etc.
5. Why does the night vision device not have a zoom function?
The more the image is enlarged, the more light is lost.
6. Why focus on both the front part (objective lens) and the eye piece (eyepiece)?
The short answer is that you're not looking through a night vision device, you're actually seeing the phosphor screen at the bottom of the tube. The objective lens focuses the image in front of the intensifier tube, which converts the image into a stream of electrons, which are then reimaged at the bottom of the tube. To see a clear image, you need to focus your eye on the bottom of the intensifier tube where the image is formed. Everyone's eye vision is different, so eye focus is also very important. Focus the line of sight first, and then transfer to the objective mirror to ensure a clear image. Also, you'll need several shots of each prism to get the sharpest image.
7. How should I use the night vision device in dim light or in complete darkness?
All night vision devices require existing light to work, and with an infrared generator, it is possible to see bright images in low light and total darkness.
8. Since the night vision device can detect infrared light, can it detect heat?
A night vision device is an optical amplifier that operates in the "nearly visible" range of light, generally speaking, this range is in the 750-850 nm range. It cannot measure heat because the thermal frequency is much lower than the spectral frequency and requires thermal imaging.
9. What type of light source is harmful to the night vision device?
Night vision devices are designed for use in dark environments, and can endanger or even damage the device if used in daylight or in very bright environments. Remember: If you point the night vision device directly at strong direct light, such as projectors, car headlights, strong torch light, etc., it may damage your night vision device. Having said that, night vision goggles all have protection from this type of damage, most simply by turning off the overload circuit, but some use more sophisticated equipment and spectroscopic devices.
10. Special design of night vision device?
Night vision devices are designed to be automatically shorted when not in use, and only start to work when the start switch is pressed. The binocular device has an "on/off" switch that requires the user to turn off the device after use. It is normal if there is a certain "humming" sound, it is intentionally designed to help the user distinguish between power on and power off. The image in the night vision device is formed by a phosphor screen, which has a little astigmatism, so it cannot be as clear as a daytime telescope. Tiny black spots may be seen in the image, which is a natural phenomenon caused by the process of manufacturing the intensifier tube, not a quality problem.
11. What's in the night vision goggle barrel?
A night vision goggle barrel consists of a set of optics (glass), a simple power supply (battery pack, wiring, transformers, rectifiers, and capacitors) and an image intensifier (a light-sensitive material coated on one end and a A glass vacuum tube with a phosphor screen).
