Ultrasonic probe for detecting a three-dimensional vibration

We propose a contact ultrasonic probe which can detect a three-dimensional vibration and separate it into its X, Y and Z components. The performance is realized using two Lamb waves and a shear horizontal (SH) wave simultaneously. The vibration in the Y direction is detected using the zeroth-order symmetrical (S0) mode SH wave, which has a displacement in only the Y direction. Those in the X and Z directions are detected using the zeroth-order asymmetrical (A0) and S0 mode Lamb waves, respectively. In a region in which the substrate is thinner than the wavelength, the A0 mode Lamb wave has a displacement in only the X direction, and the S0 mode, only in the Z direction.