Abstract
In a variety of industrial products, paint is important for preservation, waterproof, color effect and so on. Previously, depending on the type of substrate, various film thickness meters, based on electromagnetic induction, eddy-current, or ultrasound, have been widely used. However, all of them are contact thickness meter, so it was difficult to use them on moving or wet films. To solve this limitation, we focused on free-space-propagating, pulsed THz radiation. In this paper, we demonstrated non-contact, remote thickness measurement of the paint film based on time-resolved measurement of THz pulse echo. The thickness resolution of 23 μm and precision of 8 |am were achieved.
