Infrared sensing systems can be divided into five categories according to their functions. They are measurement systems that use infrared rays as the medium. According to the detection mechanism, they can be divided into photon detectors and thermal detectors. Infrared sensing technology has been used in modern technology, national defense, industry and agriculture and other fields. Has been widely used.
The development of infrared technology has become well known to everyone. This technology has been widely used in the fields of modern science and technology, national defense technology, industrial and agricultural science and technology. Infrared sensing system is a measurement system that uses infrared rays as the medium. It can be divided into Five categories: (1) Radiometer, used for radiation and spectrum measurement; (2) Search and tracking system, used to search and track infrared targets, determine its spatial position and track its movement; (3) Thermal imaging system , can produce a distribution image of the entire target infrared radiation; (4) Infrared ranging and communication system; (5) Hybrid system, which refers to a combination of two or more of the above types of systems.
It is mainly made of a material with a high thermoelectric coefficient, such as lead zirconate titanate ceramics, lithium tantalate, triglyceride titanium sulfate, etc., and is a detection element with a size of 2*1mm. One or two detectors are installed in each detector. Detection element, and connect the two detection elements in series with reverse polarity to suppress interference caused by the increase in its own temperature. The detection element converts the detected and received infrared radiation into a weak voltage signal, which is installed in the probe The field effect tube amplifies and outputs it outward. In order to improve the detection sensitivity of the detector and increase the detection distance, a Fresnel lens is generally installed in front of the detector. The lens is made of transparent plastic. The upper and lower parts of the lens are The lower two parts are each divided into equal parts to make a lens with a special optical system. It cooperates with the amplification circuit to amplify the signal by more than 70 decibels, so that the movements of people within a range of 10 to 20 meters can be measured. Nowadays, infrared sensing systems combined with Fresnel lenses have been widely used in many fields, such as human body temperature sensing, smart home systems, robot AI fields, and various human body infrared sensing fields.
The central wavelength of infrared rays radiated by the human body is 9~10-um, and the wavelength sensitivity of the detection element is almost stable within the range of 0.20-um. A window equipped with a Fresnel lens is opened at the top of the sensor. This Fresnel lens The wavelength range of the light that can be passed through the pediatric lens is 7~10–um, which is just suitable for the detection of infrared radiation of the human body. Infrared rays of other wavelengths are absorbed by the Fresnel lens, thus forming a special lens for detecting the human body. Radiated infrared sensor.
