| 摘要 |
PURPOSE:To improve efficiency by specifying the thickness of an oscillator a quarter as large as a wavelength so that the impedance Z0 of an acoustic matching plate is larger than (Z1.Z2)<1/2> when the acoustic impedance of the oscillator is Z1 and the acoustic impedance at a propagation part is Z2. CONSTITUTION:The acoustic impedance of the acoustic matching layer 3 is denoted as Z0 and that of the oscillator 1 is represented as Z1. Further, the acoustic impedance of a shoe 2 made of an organic solid such as acrylic resin and epoxy resin is denoted as Z2. In this case, the thickness of the acoustic matching layer 3 is set 1/4 or slightly small as large as the wavelength of an ultrasonic wave to obtain Z0>(Z1.Z2)<1/2>, and glass is used for the material. Consequently, the propagation characteristics of ultrasonic waves is improved to constitute an ultrasonic flow meter which is not influenced by the thickness of a duct and an ultrasonic transceiver which has wide band width characteristics such as a nondestructive inspecting device which requires a short pulse by using inexpensive materials. |
