CONVERTER, SYSTEM AND METHOD WITH IMPROVED RESOLUTION FOR TRANSFERRING AND/OR TRANSMITTING WAVES PROPAGATED BY VIBRATION

摘要

Problems of resolution and focussing arise in the near field in systems employing radiation, including ultrasonic systems. These problems can be alleviated by suppressing the plane waves in the combination of plane waves and edge waves usually employed. Several ultrasonic transducers with this property are described and in one a piezoelectric disc with surface electrodes is non-linearly polarized to transmit edge waves without plane waves.