摘要 |
The present invention provides an ultrasonic transducer structure, comprising a first ultrasonic transducer element ( 1 ), arranged and operable for transmitting an ultrasonic signal from a front face of the structure, damping material ( 2 ) at the back of the first ultrasonic transducer element ( 1 ), and a second ultrasonic transducer element ( 3 ) in or on the damping material behind the first ultrasonic transducer element ( 1 ), arranged and operable to receive sound energy propagated through the damping material ( 2 ) when the first ultrasonic transducer element ( 1 ) is operated to transmit an ultrasonic signal from the front face. Although sound energy propagating through the damping material ( 2 ) is rapidly attenuated, sound energy of a sound pulse travelling to the second ultrasonic transducer ( 3 ) from the back face of the first transducer element 1 can be received and the size or amplitude and time delay (arrival time) of this pulse can be monitored and from this information the performance of the first transducer element ( 1 ) concerned can be monitored.
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