| 摘要 |
The ultrasonic transducer is used for transmitting ultrasonic oscillations of predetermined wavelengths in a liquid propagation medium. The ultrasonic transducer is a transducer element of piezoelectric material and a lambda /4 matching layer, adjoining the propagation medium, which has an acoustic impedance which is between that of the material of the transducer element and that of the propagation medium. The lambda /4 matching layer consists of poreless glass ceramic material which contains both the glass phase and the crystalline phase and which exhibits an acoustic impedance matching the propagation medium. A glass ceramic material of about 55% uniform platelet-shaped mica crystals and about 45% glass matrix is particularly suitable as material for the lambda /4 matching layer.
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