DEVICE FOR MEASURING COATING THICKNESS

The invention relates to a device for measuring a thickness of a dielectric layer (8) on a base substrate (7), comprising a cylindrical resonant cavity (1) having a circular cylindrical wall (9) and a plane wall (10) on one end thereof, wherein the opposite end (3) is open to be placed upon the dielectric layer (8) on the substrate (7) to form a wall of the resonant cavity (1) on the opposite end (3); an antenna (4) located within said resonant cavity (1) and adapted to excite an electromagnetic field in the resonant cavity (1) that is approximately zero in the dielectric layer (8); a reflection meter (5) connected to said antenna (4) and adapted to measure the resonant frequency of the resonant cavity (1); and a processor (6) connected to said reflection meter (5) and adapted to determine the thickness of the dielectric layer (8) from the resonant frequency of the resonant cavity (1). The invention also relates to a method for measuring a thickness of a dielectric layer (8) on a base substrate (7) having a curved surface, the method comprising placing a thin conductive foil onto the curved surface to closely fit the curved surface, at least in an area to be measured; performing, using an aforementioned device, a first thickness measurement in the area to be measured to derive a thickness compensation data; removing the thin conductive foil; performing, using said device, a second measurement in the area to be measured to derive uncompensated thickness data; and applying said thickness compensation data to said uncompensated thickness data to derive the thickness of said dielectric layer (8).