| 摘要 |
In an ultrasound transducer consisting of ceramic and highly polymerised materials, a plurality of elements are arranged in layers one above the other and in an acoustically connected manner with respect to the sound propagation direction, the piezoceramic elements, which are fitted on a carrier material, acting as transducers and carrier material for the elements (located thereon) of the piezoelectric high polymer, which elements can likewise be operated as transducers. During operation as an SE test head, the piezoceramic elements are connected as transmitters and the piezo polymer elements as receivers in the respectively favourable operating mode, the advantage being, compared to elements which are mutually laterally offset, that the respective directionalities overlap, and it being possible to increase the bandwidth in comparison with a transducer which consists (entirely) of piezoceramic materials. Both transducer materials can also in each case be intrinsically used reciprocally as transmitters and receivers. As a result of the high bandwidths of thin piezo polymer films, a plurality of transducers having different frequency-transmission responses can thus be accommodated in one test-head housing. Different focusing characteristics can be achieved at the same time by the insertion of an acoustic lens between two transducer materials.
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