Working principle of infrared radiometer
In nature, when the temperature of an object is higher than zero, due to the existence of its internal thermal motion, it will continuously radiate electromagnetic waves to the surroundings, which includes infrared rays with a wave band of 0.75µm to 100µm. The size of the infrared radiation energy of the object and Its distribution according to wavelength has a very close relationship with its surface temperature. Therefore, by measuring the infrared energy radiated by the object itself, its surface temperature can be accurately determined. The infrared radiometer works according to this principle.
Infrared radiometer irradiance and emissivity relationship
The irradiance E refers to the radiant energy flux passing through a certain unit area, which is related to the wavelength. The irradiance within a unit wavelength is called the monochromatic irradiance Eλ, which is expressed as follows:
The radiance Lω refers to the radiant flux passing through the unit projected light source area along the direction of the unit solid angle in a given direction in three-dimensional space, and is related to the direction of the co-established solid angle. The relationship between the two is as follows:
Where θ is the angle between the surface element normal and the incident light, and α is the azimuth angle. The concept of emissivity is mainly used in infrared radiometers. Each radiometer has its own field of view, and only the radiant flux within this field of view, that is, the solid angle, can be received by the radiometer.
Infrared radiometer use
1. Security engineering infrared lighting detection
2. Infrared camera performance test
3. Infrared lamp performance testing
