Principle of operation and characteristics of infrared thermometers
1 blackbody radiation and infrared thermometry principle
All the temperature above absolute zero of the object are constantly sending out infrared radiation energy to the surrounding space. The size of the object's infrared radiation energy and its distribution by wavelength - and its surface temperature has a very close relationship. Therefore, through the measurement of the infrared energy radiated by the object itself, it will be able to accurately determine its surface temperature, which is the objective basis for infrared radiation thermometry.
Blackbody radiation law: blackbody is an idealized radiation body, which absorbs all wavelengths of radiant energy, no energy reflection and transmission, the emissivity of its surface is 1, the other material reflection coefficient is less than 1, known as the grey body. It should be noted that there is no real black body in nature, but in order to clarify and obtain the distribution of infrared radiation law, in the theoretical study must choose the appropriate model, which is Planck put forward by the body cavity radiation quantisation vibronic model, which led to Planck's law of the black body radiation, that is, expressed in wavelengths of the black body spectral radiance, which is the starting point of all infrared radiation theory, so it is called the law of the black body radiation.
Infrared thermometer features
All temperatures higher than absolute zero objects are constantly sending infrared radiation energy to the surrounding space. The size of infrared radiation energy distribution by wavelength and its surface temperature has a very close relationship. Therefore, through the measurement of the infrared energy emitted by the object itself, it will be able to accurately measure its surface temperature. Infrared thermometer can receive a variety of objects themselves emit invisible infrared radiation energy. Infrared radiation is part of the electromagnetic spectrum, infrared is located between visible light and radio waves. When the instrument temperature measurement, the infrared radiation energy emitted by the object under test, through the optical system of the pyrometer in the detector into an electrical signal, and through the infrared pyrometer display part of the surface temperature of the object under test.
Infrared thermometer features: non-contact measurement, wide temperature range, fast response speed, high sensitivity. However, due to the impact of the emissivity of the object to be measured, it is almost impossible to measure the real temperature of the object to be measured, the measurement is the surface temperature.
