Ultrasonic scanning transducer

Ultrasonic scanning apparatus adapted for use in an ultrasonic scanning system that examines an object by directing a times series of ultrasonic waves into the object and provides said scanning system with information borne by the ultrasonic echoes generated when said waves strike acoustical interfaces within the object comprising:

• a housing containing a liquid through which said waves and echoes can pass;
• at least one transducer element disposed within said housing for receiving electrical energy and, in response thereto, directing ultrasonic waves into the object and for receiving the ultrasonic echoes and generating therefrom information-bearing electrical energy;
• a permanent magnet to which said transducer element is fixed, said permanent magnet being mounted within said housing for rotational movement;
• bearing means for mounting said permanent magnet within said housing for said rotational movement;
• and
• a stator assembly for receiving a periodic electrical signal having a zero average value and, in response thereto, establishing a unidirectionally rotating primary magnetic field capable of exerting a force on said permanent magnet and rotating said permanent magnet and transducer element in the direction of rotation of said primary magnetic field.