This article describes the characteristics of the infrared sensors
infrared sensor definition
In engineering, the position (band) occupied by infrared in the electromagnetic spectrum is divided into four bands: near-infrared, mid-infrared, far-infrared, and extremely far-infrared. Any substance, as long as it has a certain temperature (above absolute zero), can radiate infrared rays.
The basic principle of infrared sensor measurement
First, let’s learn about infrared light. Infrared light is part of the solar spectrum. The greater feature of infrared light is its photothermal effect and radiant heat. It is a larger photothermal effect area in the spectrum. Infrared light is an invisible light. Like all electromagnetic waves, it has the properties of reflection, refraction, scattering, interference, and absorption. The propagation speed of infrared light in vacuum is 300000Km/s. Infrared light will attenuate when propagating in the medium, and the attenuation in metal is very large, but infrared radiation can pass through most semiconductors and some plastics, and most liquids absorb infrared radiation very much.
Different gases have different absorption degrees, and the atmosphere has different absorption bands for different wavelengths of infrared light. Research and analysis have shown that infrared light with wavelengths of 1 to 5 μm and 8 to 14 μm has a relatively large "transparency". That is, infrared light of these wavelengths can penetrate the atmosphere well. Any object in nature, as long as its temperature is above absolute zero, can produce infrared radiation. The photothermal effect of infrared light is different for different objects, and the intensity of heat energy is also different. For example, black bodies (objects that can fully absorb the infrared radiation projected on its surface), mirror bodies (objects that can fully reflect infrared radiation), transparent bodies (objects that can completely penetrate infrared radiation), and gray bodies (partially reflective or Objects that absorb infrared radiation) will produce different photothermal effects.
Strictly speaking, there are no black bodies, mirror bodies and transparent bodies in nature, and most objects are gray bodies. The above-mentioned characteristics are the important theoretical basis for the use of infrared light radiation technology in military and scientific research projects such as satellite remote sensing and telemetry and infrared tracking.
The physical nature of infrared radiation is thermal radiation. The higher the temperature of the object, the more infrared radiation is emitted, and the stronger the energy of infrared radiation. Studies have found that the thermal effects of various monochromatic lights in the solar spectrum gradually increase from purple light to red light, and that greater thermal effects appear in the frequency range of infrared radiation, so people call infrared radiation thermal radiation or heat Rays.
The development trend of infrared sensors
1. Intelligent: The current infrared sensor is mainly used in combination with peripheral equipment, and the intelligent sensor has a built-in microprocessor, which can realize two-way communication between the sensor and the control unit. It has the advantages of miniaturization, digital communication, and simple maintenance. It can be used as a single The modules work independently.
2. Miniaturization: The miniaturization of sensors is an inevitable trend. In current applications, due to the volume problem of the infrared sensor, its use is far worse than the thermoelectric corner. Therefore, whether the infrared sensor is miniaturized and portable or not has an impact on its development prospects.
3. High sensitivity and high performance: In medicine, in human body temperature testing, infrared sensors have been widely used due to their rapid measurement, but they are limited in their accuracy and cannot replace the existing body temperature measurement methods. Therefore, high sensitivity and high performance of infrared sensors are the inevitable trend of its future development.
Although there are still many shortcomings of infrared sensors at this stage, infrared sensors have played a huge role in modern production practices. With the improvement of detection equipment and other parts of the technology, infrared sensors can have more performance and Better sensitivity will also have a wider range of applications.
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