Working principle and characteristics of infrared thermometer
1 Black body radiation and infrared temperature measurement principle
All objects with a temperature higher than absolute zero are constantly emitting infrared radiation energy to the surrounding space. The size of the infrared radiation energy of an object and its distribution according to the wavelength have a very close relationship with its surface temperature. Therefore, by measuring the infrared energy radiated by the object itself, its surface temperature can be accurately determined, which is the objective basis for infrared radiation temperature measurement. the
Black body radiation law: A black body is an idealized radiator that absorbs radiation energy of all wavelengths, has no reflection and transmission of energy, and has an emissivity of 1 on its surface, and the reflection coefficient of other materials is less than 1, which is called a gray body . It should be pointed out that there is no real black body in nature, but in order to clarify and obtain the distribution law of infrared radiation, an appropriate model must be selected in theoretical research, which is the quantized oscillator model of body cavity radiation proposed by Planck, thus deriving Planck's law of black body radiation, that is, the black body spectral irradiance represented by wavelength, is the starting point of all infrared radiation theories, so it is called the law of black body radiation.
2 Features of infrared thermometer
All objects with a temperature higher than absolute zero are constantly emitting infrared radiation energy to the surrounding space. The distribution of infrared radiation energy according to the wavelength has a very close relationship with its surface temperature. Therefore, by measuring the infrared energy emitted by the object itself, its surface temperature can be accurately measured. Infrared thermometers can receive invisible infrared radiation energy emitted by various objects themselves. Infrared radiation is the part of the electromagnetic spectrum that lies between visible light and radio waves. When the instrument measures temperature, the infrared radiation energy emitted by the measured object is converted into an electrical signal on the detector through the optical system of the thermometer, and the surface temperature of the measured object is displayed through the display part of the infrared thermometer.
Infrared thermometer features: non-contact measurement, wide temperature range, fast response, high sensitivity. However, due to the influence of the emissivity of the measured object, it is almost impossible to measure the real temperature of the measured object, and the surface temperature is measured.
