Noncontact and Nondestructive Thickness Measurement for Multilayer Paint Using Terahertz Wave

概要

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Despite the importance of thickness control to guarantee paint qualities, there was no effective tool to measure thickness of each layer without contact.We here propose the use of terahertz wave as a new measurement tool for paint thickness. Terahertz wave comprises electromagnetic waves with the frequency, around 1 THz, and the wave penetrates paint layers easily with its remarkable transparency. We demonstrate the echo-pulse thickness measurement like sonar, using 100 fs (1×10−13 s) terahertz pulse, of which ultrashort temporal duration leads to high depth resolution of 10 μm. The thickness of each layer can be measured individually at a time.Our system, which is based on fiber laser technology, is compact, stable, and capable to be used by setting to the edges of the robot arms. Furthermore, this method is noncontact measurement, so that it can measure thickness under both dry and wet conditions. This technology will realize the real-time measurement of paint thickness in a paint booth. We hope our technology, using terahertz wave, will make a contribution to paint quality control in near future.
Japan Society of Colour Materialの論文