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The Basic Theory Of Infrared Thermometer
- Feb 09, 2018 -

In 1672, it was discovered that sunlight (white light) is a combination of light of various colors, and Newton made the famous conclusion that monochromatic light is simpler in nature than white light. The use of dichroic prism on the sun (white light) is broken down into red, orange, yellow, green, blue, purple and other monochromatic light.

In 1800, British physicist F. W. Heusl discovered infrared light when studying various colored lights from a hot point of view. While studying the heat of various colors, he deliberately blocked the only window in the darkroom with a darker panel and opened a rectangular hole in the panel with a dichroic prism inside. When the sunlight passes through the prism, it is broken down into colored bands and the thermometer is used to measure the amount of heat in the different bands in the band. In order to compare with the ambient temperature, Husserl used several thermometers near the colored light bands to measure the ambient temperature. During the experiment, he stumbled upon a curious phenomenon: a thermometer placed outside of the red band of light, higher than the indication of any other temperature in the room. After repeated testing, the so-called high-temperature high-temperature zone, always at the edge of the light outside the red light. So he announced that in addition to the visible light emitted by the sun, there is a kind of invisible "hot line", which can not be seen. The invisible "hot line" is located outside the red light and is called infrared light. Infrared is an electromagnetic wave with the same nature as radio waves and visible light. The discovery of infrared ray is a great leap forward in understanding of nature and opens up a brand new broad field in the research, utilization and development of infrared technology.

Infrared wavelengths between 0.76 ~ 100μm, according to the wavelength range can be divided into near-infrared, mid-infrared, far-infrared, far infrared four categories, its electromagnetic spectrum in the continuous spectrum of radio waves in the region between the visible and light . Infrared radiation is one of the most widespread electromagnetic radiation in nature. It is based on the random movement of molecules and atoms in any object under normal circumstances, and continuously radiates the thermal infrared energy, the movement of molecules and atoms The more intense, the greater the energy of the radiation, on the contrary, the smaller the radiation energy.

Objects whose temperature is above absolute zero will radiate infrared light due to their own molecular motion. After converting the power signal radiated by the object into the electrical signal through the infrared detector, the output signal of the imaging device can completely simulate the spatial distribution of the temperature of the surface of the scanned object, which is processed by the electronic system to be transmitted to the display screen to obtain the Corresponding thermal profile of the object surface thermal image. Using this method, we can achieve long-range thermal imaging of the target image and temperature measurement and analysis to determine.