Patent ID: 9194687
Filing Date: 2015-11-24
Classification: G01B

Abstract:
1. A method of measuring coating thickness for defects, the method comprising: providing a composite substrate; including a conductive layer over a surface of the composite substrate; depositing a plurality of non-conductive coating layers over the conductive layer; providing an eddy-current measuring coil formed on a printed circuit board (PCB), the coil having a driving trace having first and second driving electrodes and a receiving trace having first and second receiving electrodes, the receiving and driving traces being either coaxial or interwoven, spaced apart, and sharing a common center; administering a load in a frequency range from 10 to 100 MHz to the first and second driving electrodes using an eddyscope; measuring the load across the first and second receiving electrodes to determine impedance; and using the impedance measured to determine a total thickness for the plurality of coating layers and whether an overall coating thickness is uniform.