As long as any object is above absolute zero, it will radiate energy at a certain wavelength, but the radiation energy is very weak at low temperature.
At room temperature, all the objects in nature are emission sources of infrared radiation, but the wavelength of infrared radiation is different. For example, the human body temperature is 37℃, the infrared radiation wavelength is 9-10μm; the infrared radiation wavelength of 400-700℃ objects is 3-5μm.
The non-contact temperature sensor is made of the principle that the radiant energy of the object changes with the temperature.
The infrared thermopile sensor transforms the absorbed infrared radiation into heat energy, and transforms the temperature change into electronic signal, which is magnified and displayed.
As a kind of non-contact infrared temperature sensor, thermopile can quickly measure the surface temperature of the object without directly contacting the measured object. It can measure the high temperature, dangerous or moving object, and it will not pollute or damage the measured object.
At present, the infrared thermopile sensor has been widely used in the fields of frontal temperature gun, ear temperature gun, intelligent home appliances, lamp switch, food temperature detection and so on.
According to the Minamata Convention on mercury signed by the government representative of the Pople's Republic of China in Kumamoto in 2013, since 2020, all Contracting States have banned the production and import and export of mercury containing products. Therefore, electronic thermometers will replace mercury thermometers and become the necessary frontal and ear thermometers for every household.