The electronic thermometer uses infrared thermopile sensor to convert the infrared radiation of human body into the change of electrical signal, so as to display the temperature of human body. Compared with the traditional mercury thermometer, the electronic thermometer has the advantages of safety, direct reading, short time and high precision.
Thermopile is based on the Seebeck effect mechanism. Two materials with different Seebeck coefficients are connected in series to form a closed-loop (i.e. a pair of thermocouples). The high temperature end of the two connected parts is usually referred to as "hot junction" and the low end is referred to as "cold junction". The carrier in the material moves along the direction of temperature gradient reduction, causing the charge to accumulate at the cold junction. At this time, there is thermoelectric potential in the road.
Thermopile is based on the mechanism of Seebeck effect, using silicon-based micro processing technology, arranging several thermocouples of thermopile on the supporting layer of silicon chip, and connecting these thermocouples in series to form a thermopile chip. When the sensor receives infrared radiation, the voltage of the thermocouples on the chip of the hot spot reactor is superposed and output, thus the test temperature is transformed into a voltage signal.
The infrared thermopile sensor is different from pyroelectric sensor by not only detecting dynamic signal, but also static signal, and accurately measure temperature.