Rubber-coupled acoustic microscopy for dry inspections of industrial products

Theory and applications of high frequency broadband ultrasound via a thin layer in contact with a solid

“…14, d PE is found to be 49 m and this is almost the same as that achieved using conventional water immersion with the same focused ultrasonic transducer (d PE = 47 m). Although the value of d PE is almost unchanged when using the thin polymer film, in the case of the dry-contact technique with a rubber membrane, the value of d PE is 30% greater than that of the water immersion case (Tohmyoh and Akaogi, 2007). This is due to the larger ultrasonic attenuation in the rubber membrane, especially at the higher frequency components.…”

“…An investigation to find a rubber membrane suitable for repeated measurements using the dry-contact ultrasonic technique was undertaken (Tohmyoh and Akaogi, 2007). Four kinds of rubber membrane, denoted R1, R2, R3 and R4, were prepared, each with a thickness of 0.2 mm.…”