| 摘要 |
An ultrasonic transducer comprises a working member (12) of piezo-electric material having at least two surface regions (13, 14) separated by a boundary surface region (15); a film layer (16, 17) of conductive material on each surface region (13, 14); a conductor (18, 19) whereby a voltage can be applied to each film (16, 17); a protective non-conducting mask (22, 23), for each of the film layers and in intimate contact therewith, the mask (22, 23) comprising a fibre reinforced material. In addition to the transducer methods are described of fabricating the transducer with intimate contact between film layer and mask. At least one passage (50, 68) can be provided through the working member (12) and a web (50A, 68A) of the fibre reinforced material located through the, or each, passage (50, 68) so that the or each web (50A, 68A) has one end integral with one mask (22, 23) and the other end integral with the other mask (23, 22) to form a mechanical link between different regions of one mask or between two masks. This arrangement provides for a stronger mechanical linkage of the protective mask (22, 23) to the body (12) of the transducer. It also serves to preserve the shape of a flexible working member (12) which is distorded into a predetermined shape prior to the mask material (22, 23) polymerising to form a rigid structure. The transducer (51) can include a backing member (60) serving to direct the acoustic output of the transducer predominantly in a particular direction (A) either by reflecting or attenuating acoustic output that would otherwise be generated in any other direction that the particular direction (A). |
