Can infrared thermometer measure body temperature?
In 1672, it was discovered that sunlight (white light) is composed of various colors of light, and Newton concluded that monochromatic light is simpler in nature than white light. By using a beam splitter, sunlight (white light) can be decomposed into monochromatic light of various colors such as red, orange, yellow, green, cyan, blue, purple, etc. In 1800, British physicist F W. Huxler discovered infrared radiation when studying various colors of light from a thermal perspective. He intentionally blocked the windows of the darkroom with dark boards while studying the heat of various colored lights, and opened a rectangular hole on the board with a beam splitter inside. When sunlight passes through a prism, it is decomposed into colored light bands, and a thermometer is used to measure the heat contained in different colors of the light bands. In order to compare with the ambient temperature, Huxler used several thermometers placed near the colored light band for comparison to measure the ambient temperature. During the experiment, he accidentally discovered a strange phenomenon: a thermometer placed outside the red light band had a higher reading than other temperature readings indoors. After repeated experiments, this so-called high temperature zone with more heat is always located outside the red light at the edge of the light band. So he announced that in addition to visible light, there is another type of radiation emitted by the sun that is invisible to the human eye, which is located outside the red light and is called infrared. Infrared radiation is an electromagnetic wave with the same essence as radio waves and visible light. The discovery of infrared radiation is a leap in human understanding of nature, opening up a new and broad path for the research, utilization, and development of infrared technology.
The wavelength of infrared radiation ranges from 0.76 to 100 μ m and can be divided into four categories: near-infrared, mid infrared, far-infrared, and extremely far-infrared. Its position in the continuous spectrum of electromagnetic waves is in the region between radio waves and visible light. Infrared radiation is a widespread electromagnetic radiation that exists in nature. It is based on the irregular motion of molecules and atoms of any object in a conventional environment, constantly radiating thermal infrared energy. The more intense the motion of molecules and atoms, the greater the energy radiated, and vice versa, the smaller the energy radiated.
Objects with temperatures above absolute zero will emit infrared radiation due to their molecular motion. After converting the power signal radiated by an object into an electrical signal through an infrared detector, the output signal of the imaging device can simulate the spatial distribution of the surface temperature of the scanned object one-to-one. After processing by the electronic system, it is transmitted to the display screen to obtain a thermal image corresponding to the surface heat distribution of the object. By using this method, it is possible to achieve remote thermal imaging and temperature measurement of the target, and analyze and judge it.
