Patent ID: 6252237
Filing Date: 2001-06-26
Classification: G01B

Abstract:
A method of measuring the thickness of a coating on a moving web, the method comprising:a) providing a web surface having a fluorescent coating;b) providing a light source;c) directing a first wavelength of light from the light source onto the coated web surface such that the coated surface absorbs the first wavelength of light and emits a second wavelength of light;d) measuring the intensity of the second wavelength of light by use of a solid state array of light-sensitive elements, wherein each element measures light corresponding to a portion of the web surface; ande) determining the thickness of the coating based on the measured intensity of the second wavelength of light from the array of the light-sensitive elements;wherein determining the thickness of the coating comprises normalizing the measured intensity of the second wavelength of light at each element of the array based on the relative position of the portion of the web surface being measured.