Abstract: A scanning device, typically ultrasonic, can make a volumetric scan of a conical scanning field. A transducer having a permanent magnet at its back end is gimbal mounted in a housing. Behind the permanent magnet is a hemispheric electromagnet coil assembly having at least two wound electromagnet coils. The coils are energized in turn with an alternating current signal, with the signal applied to any coil being out of phase with the signal applied to any other coil by 180°/n, where n is the number of coils in the hemispheric electromagnet coil assembly. Volumetric scanning is possible by periodically modulating the magnitude or frequency of the signals applied to the coils.

Abstract: An ultrasonic scanner has a housing, an ultrasonic transducer mounted within the housing for back-and-forth motion about a pivot, a permanent magnet affixed to the rear of the transducer, and electromagnetic means to effect movement of the transducer/magnet assembly. The electromagnetic means comprises two or more longitudinally mounted electromagnets, and optionally two radially mounted permanent magnets which serve as decelerating buffers. Electrical means are provided for energizing the transducer and receiving signals therefrom. Digitizing means are provided to convert the received signals to digital form. Sequential control means are provided to energize the electromagnet coils in a programmed sequence, and furthermore to synchronize transducer motion, periodic energization of the transducer, and digitization of signals received from the transducer. Display means are provided to present the signals received by the transducer to an operator, in the form of a time-varying tomographic image.