Apparatus for measuring thickness of paint coating

摘要

The present disclosure relates to an apparatus for measuring the thickness of a paint coating on a substrate. The apparatus includes at least one band-pass filter for admitting a predetermined wave range of infrared rays, including both the infrared rays reflected at the surface of the substrate and passed through the paint coating and the infrared rays radiated due to the temperature both of the paint coating and the substrate; two infrared ray sensors, one of which detects the infrared rays passed through the filter and including both of the reflected rays and the rays radiated due to the temperature, and the other of which detects only the rays radiated due to the temperature; and a processing unit in which the signals supplied from both infrared ray detectors are compared with each other and the difference representing only the reflected infrared rays are processed on the bases of reference coefficients relating to the reflection of the infrared rays at the reflection of the substrate and the absorption of the infrared rays by the paint coating to produce signals representing thickness of the paint coating.