The infrared light of the surveillance lens refers to the invisible light with a wavelength greater than 750nm. Any object in the nature is an infrared light radiation source. With this application, people can see many things in the nature that are not visible to the naked eye. In fact, infrared technology is used in many fields such as security monitoring, medical equipment, car night vision, communication detection, consumer electronics and so on. Regarding the monitoring industry, AVENIR ETOKU Seiko technicians said that the infrared function has become a trend, and as the front-end equipment for monitoring, the infrared effect of the lens plays a vital role.
The wavelengths of infrared light and visible light are different, and the focus of the two kinds of light after passing through the lens is also different, so that the three-dimensional image formed is also different. For ordinary lenses, without special correction, the image will be blurred in the morning after the focus is clear, and the infrared lens after correction can be clearly imaged in the morning.
Security lens correction methods include optical correction and special material correction. Optical correction is to eliminate chromatic aberration and reduce dispersion through different lens combinations. Special material correction is to use low dispersion materials (usually ED glass) to grind the lens. In terms of effect, the ability of optical correction is infinite, and with the help of ultra-low dispersion lenses and coating antireflection technology, it can greatly reduce chromatic aberration and ensure that different wavelengths of light are focused on the same focus.
DZO technicians introduced that infrared lenses corrected with special materials can usually be used in the following scenarios:
1. 24/7 surveillance camera
The second most important use of infrared lens is to complete all-weather monitoring. The infrared lens after optical correction, after focusing in the daytime, usually needs to be refocused in the morning; and the infrared lens after special material correction can make the visible light and infrared focus to the same focus, so after focusing in the daytime, turn on the infrared at night Fill light can still be clearly imaged.
2.Through the fog
Fog penetration stems from the monitoring requirements in long-distance and complex environments. Fog is composed of coarse particles floating in the air. The more particles per unit volume, the denser the fog. Visible light has a short wavelength and cannot penetrate the mist. This is why the visibility in the foggy morning is very low. The near-infrared light has a longer wavelength. This feature allows infrared light to diffract huge particles and complete the purpose of fog penetration.
In the fog transmission mode, the filter will filter out the visible light and only save the infrared light. With the coating antireflection technology, the fog transmission lens can complete the long-distance all-weather monitoring under the condition of extremely low visibility, and in the normal and fog transmission modes keep the focal plane from shifting.
3.Laser night vision
The laser is a highly concentrated monochromatic light, so infrared laser can be used to achieve long-distance night vision monitoring. The laser beam scans the object, and the object reflects the beam back and can be imaged after focusing by the lens. Infrared lasers are commonly used, and their wavelengths are in the near-infrared wavelength range, so infrared lenses must be used to match the laser equipment. Infrared lens corrected by special material can penetrate 950nm light source, and it can be used with infrared laser to realize super long distance night vision monitoring.