Object`s e.g. polymer film, opto-geometric characteristic e.g. thickness, measuring method for e.g. packaging industry, involves determining thickness based on refractive index or index based on thickness from Fourier transform of fringes

摘要

The method involves illuminating an object (2) by an incident wave (Ei) from a wide band light source e.g. white light source, in a transparency range of the object. A light reflected and transmitted by the object is collected, where the light has interferences and an illumination result. The light is analyzed by a high resolution spectrometer so as to cause heterochromatic fringes. Thickness of the object is determined based on refractive index of the object, or the refractive index is determined based on the thickness from Fourier transform of the fringes.