Polymer film thickness measurement using laser‐ultrasound techniques

The thickness of thin polyester film has been measured using ultrasonic Lamb waves which were generated and detected using noncontacting laser techniques. The uncertainty analysis of such a measurement technique has been examined. Systematic errors in both time of flight and distance between laser generation and detection points were estimated and reduced with the assistance of computerized X‐scan translation techniques. Thickness measurements with uncertainties of less than 3% have been achieved.