The ear thermometer is a non-contact telemetry (although it may be less than one centimeter) temperature measurement instrument. It uses the infrared spectrum emitted by the eardrum (equivalent to the hypothalamus) to determine the body temperature. According to the black body radiation theory, it is different The infrared spectrum produced by temperature objects is also different. The thermopile infrared detector can be accurate to 0.1 ℃, and then converted by the microcomputer to display the reading.