Study of the Measurenet of Acoustic Properties of Film Samples Using Ultrasonic Micro Spectroscopy

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Measurement principles and system for sound velocity of liquids and solids using sound reflectivity G and sound transmittance T have been developed. Sound reflectivity G and sound transmittance T were calculated for various combinations of ultrasonic transducer and samples to find the optimum sound frequency and sample thickness. From the simulations, our method can be applied under the condition of h/lambda<0.1-0.01 in water and h/lambda<0.001 in air has been certified, respectively.The measurement system introducing the synthesized function generator and various ultrasonic transducers has established the broad band inspection. Moreover, the high precision mechanical stage enabled the alignment between the ultrasonic transducer and the sample with higher accuracy. On-lined system can be made the automatic measurement.The experiments with various films and thin plate materials such as films and foils has been accomplished. The results have the agreement with those of other method within 1%. The experiments with thin layr (-1mm) of liquids have been also made. In the method, the quantity of sample required in the measurement was only less than 0.1cc.Alternative experiments for the noncontact thickness measurements with thin samples using the same principles as described above, has been made using 40 kHz ultrasonic wave in air. Metal foils and papers having the micro meter order thickness have been successfully measured within some % differences from those measured by micro meter.