POLYMER FILM THICKNESS DETERMINATION WITH A HIGH-PRECISION SCANNING REFLECTOMETER

A fiber-optic-based optical low coherence reflectometer (OLCR) is used to measure the thickness of polyester films. The measurements are mad e on both stationary and moving films to show the feasibility of this technique in a process environment. Autocorrelation is used to extract useful data from raw reflectometry data, and a statistical analysis o f the data from both moving and stationary films is done to help demon strate the application of this method. Although the reflectometer is n ot optimally configured for process analysis, a reliable estimate of p olymer film thickness is shown in less than one minute measurement tim e for the moving films.