Ultrasonic transducer with piezoelectric substrate - has AC voltage with specified phase difference applied to groups of interdigitated electrodes to produce focussed beam

摘要

The ultrasonic transducer produces a beam of waves focussed at a single point and may be operated in a pulsed mode. It may be used in microscopes, medical applications, non-destructive testing, etc. At least one group (10) of interdigital electrodes is provided on a piezoelectric substrate surface. Each group (4a, 4b) has several pairs or triplets of interdigitated electrodes, the pairs (triplets) being arranged one above the other in the direction of the fingers. An a.c. voltage with a specified phase difference is applied to the electrodes.