| 摘要 |
An ultrasonic transducer (W) is used to produce sound waves with a rotationally symmetrical beam lobe. At least one scattering body (4) is positioned in the direction of sound propagation within the Fresnel zone of the ultrasonic transducer. The scattering body may be elongate in shape and positioned at right angles to the direction of sound propagation. Various other shapes are also claimed. |
