Application of crossed teflon diffuser to coatings on oriented surfaces

摘要

A system and method for measuring coating thickness upon a substrate containing directionally oriented elements is disclosed. A near infrared light is directed upon the coating and reflected near infrared light is collected to determine the coating thickness. A pair of stacked and crossed diffuser elements is placed between the light source and the sample, and between the sample and the reflected near infrared light collector to improve the accuracy of the measurement, especially for coating thickness of less than about 2 mils and for coatings on substrates containing directionally oriented components. Each diffuser element is formed of a polytetrafluoroethylene fluoropolymer (PTFE) film.