How does an infrared thermometer work?

Understanding the working principle, technical specifications, working conditions, operation and maintenance of infrared thermometers is the basis for users to choose or use infrared thermometers correctly.

All objects above absolute zero are radiating infrared energy into the surrounding space. The infrared radiation energy and its wavelength distribution of an object are closely related to its surface temperature. Therefore, the surface temperature of the object can be accurately detected by measuring the infrared energy of the object, which is the objective basis for infrared radiation temperature measurement.

Also, it requires reference to the law of black body radiation. Blackbodies are good heat sinks. It absorbs radiant energy at all wavelengths, but neither reflects nor transmits energy. Its surface has an emissivity of 1. The north and south tides remind you: there is no real black body in nature. However, in order to understand and obtain the distribution law of infrared radiation, it is necessary to select an appropriate model in theoretical research, which is the quantized oscillator model of body cavity radiation proposed by Planck. On this basis, Planck's black body radiation law is derived, that is, the spectral radiance of a black body is expressed by wavelength. This is the basis of all infrared radiation theory, known as the law of black body radiation.

Almost all practical objects in nature are not black bodies. The radiation amount of an actual object depends not only on the radiation wavelength and the temperature of the object, but also on the material, preparation method, thermal process, surface state and environmental conditions of the object. Therefore, in order to ensure that the law of black body radiation is applicable to all practical objects, it is necessary to introduce a scale factor related to material properties and surface states, that is, emissivity. This coefficient indicates how close the thermal radiation of the actual object is to the black body radiation, and the value is generally between 0 and 1. According to the law of radiation, as long as the material emissivity and infrared radiation characteristics of any object are known, it can be obtained. What are the main factors affecting emissivity? There are material types, surface roughness, physical and chemical structure, material thickness, etc. Infrared thermometer temperature measurement

Infrared thermometer consists of optical system, photoDetector, signal amplifier, signal processing and display output. The optical system of an infrared thermometer accumulates targeted infrared energy within its field of view. The size of the field of view is determined by the optical components and position of the infrared thermometer. Infrared energy is focused on a photoDetector and converted into a corresponding electrical signal. The signal is corrected by the amplifier and signal processing circuit according to the internal algorithm of the instrument and the emissivity of the target, and then converted into the temperature value of the measured target.