Basics
MI 11
4Basics
4.1MeasurementofInfraredTemperature
All surfaces emit infrared radiation The intensity of this infrared
radiation changes according to the temperature of the object.
Depending on the material and surface properties, the emitted
radiationliesinawavelengthspectrumofapproximately1to20μm.
Theintensityoftheinfraredradiation(”heatradiation”)isdependent
on
the material. For many substances this material‐dependent
constant is known. This constant is referred to asthe ”emissivity
value”.
Infraredthermometers areoptical‐electronicsensors. Thesesensors
are sensitive to the emitted radiation. Infrared thermometers are
madeupofalens,aspectralfilter,a sensor,andanelectronic
signal
processing unit. The task of the spectral filter is to select the
wavelength spectrumof interest.The sensor converts theinfrared
radiationintoanelectricalsignal.Thesignalprocessingelectronics
analyze the electrical signals and convert it into a temperature
measurement. Astheintensity ofthe e mittedinfrared radiationis
dependentonthematerial,therequiredemissivitycanbeselected on
thesensor.
Thebiggestadvantageoftheinfraredthermometerisitsabilityto
measure temperature without touching an object. Consequently,
surfacetemperaturesofmovingorhardtoreachobjectscaneasilybe
measured.
