What is the working principle of an infrared temperature sensor?
The temperature detection principle of an infrared thermometer is based on the blackbody radiation law. As we all know, all objects in nature above absolute zero constantly radiate energy outward. The magnitude and wavelength distribution of the energy radiated by an object are closely related to its surface temperature; the higher the temperature of an object, the stronger its infrared radiation. The spectral radiant exitance of a blackbody is determined by Planck's formula.
The following figure shows the blackbody spectral radiance at different temperatures:
We can see from the curves in the graph that blackbody radiation has several characteristics:
1. At any temperature, the spectral radiance of a blackbody changes continuously with wavelength, and each curve has only one maximum value;
2. As temperature increases, the wavelength corresponding to the maximum spectral radiance decreases. This indicates that with increasing temperature, the proportion of short-wavelength radiation in blackbody radiation increases;
3. As the temperature increases, the blackbody radiation curve further increases, meaning that at any given wavelength, the spectral radiance corresponding to higher temperatures is also greater, and vice versa.
What are the applications of infrared temperature sensors?
To measure temperature, point the instrument at the object to be measured, press the trigger, and read the temperature data on the instrument's LCD. Ensure the distance, spot size ratio, and field of view are properly aligned. There are a few important things to remember when using an infrared thermometer:
Infrared thermometers can only measure surface temperature; they cannot measure internal temperature. Temperature cannot be measured through glass, as glass has unique reflection and transmission characteristics that prevent accurate infrared temperature readings. However, temperature can be measured through an infrared window. Infrared thermometers are best avoided for measuring the temperature of shiny or polished metal surfaces.
Some measuring instruments can change emissivity, and emissivity values for various materials can be found in published emissivity tables.
Other instruments have a fixed preset emissivity of 0.95. This emissivity value is used to compensate for the surface temperature of most organic materials, painted or oxidized surfaces by applying a tape or matte black paint to the surface being measured. When the tape or paint reaches the same temperature as the substrate material, the temperature of the tape or paint surface is measured, which is the true temperature. What is the principle of an infrared temperature sensor?
What is the working principle of an infrared temperature sensor? Having read this, you should now have a deeper understanding of how infrared temperature sensors work! Infrared temperature sensors are extremely convenient to use, greatly improving the efficiency of body temperature detection. It is believed that with the rapid advancements in the principles of infrared temperature sensors, the technology will become increasingly sophisticated and mature in the future, making them even easier to use!
