Working principle and thermometer of infrared temperature measurement method
All objects with temperatures above absolute zero are constantly emitting infrared radiation energy into the surrounding space. The magnitude and wavelength distribution of infrared radiation energy of an object are closely related to its surface temperature. Therefore, by measuring the infrared energy radiated by an object itself, its surface temperature can be accurately determined, which is the objective basis for infrared radiation temperature measurement.
Blackbody radiation law: A blackbody is an idealized radiation body that absorbs radiation energy of all wavelengths without energy reflection or transmission. Its surface emissivity is 1, and the reflection coefficient of other substances is less than 1, which is called a gray body. It should be pointed out that there is no true blackbody in nature, but in order to clarify and obtain the distribution law of infrared radiation, a suitable model must be selected in theoretical research. This is the quantized oscillator model of body cavity radiation proposed by Planck, which derived Planck's law of blackbody radiation, namely the spectral radiance of blackbody radiation expressed in wavelength. This is the starting point of all infrared radiation theories, hence it is called the blackbody radiation law.
All objects with temperatures above absolute zero are constantly emitting infrared radiation energy into the surrounding space. The distribution of infrared radiation energy according to wavelength is closely related to its surface temperature. Therefore, by measuring the infrared energy emitted by an 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 a part of the electromagnetic spectrum, located 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 on the display part of the infrared thermometer.
Characteristics of infrared thermometer: non-contact measurement, wide temperature measurement range, fast response speed, high sensitivity. However, due to the influence of the emissivity of the tested object, it is almost impossible to measure the true temperature of the tested object, and only the surface temperature is measured.
