Abstract: In a mechanical sector scanner, a first bevel gear is mounted on the end of an output shaft of a motor, and an ultrasonic transducer is rotatably supported for rotating about a scanning axis transverse to the output shaft. A second bevel gear engaging the first bevel gear is mounted on the back surface of the transducer. The output shaft oscillates about an output axis. Oscillations of the output shaft are coupled to the transducer by the bevel gears. The second gear has a plurality of teeth arranged in an arc less than completely around the scanning axis, and the second gear is so disposed that the back surface of the transducer is nearer to the scanning axis than the teeth.

Abstract: Ultrasonic interrogating apparatus for needle insertion has an array of ultrasonic transducers, electronics for exciting the transducers to ultrasonic emission and receiving ultrasonic echoes therefrom, a housing for the electronics having first and second ends, and a display for presenting the received echoes. The array of transducers is seucred to the electronics housing in laterally offset relationship therefrom. The passage extends through the array of transducers without extending through the electronics housing. A needle is inserted through the passage in the transducer array for the purpose of aspiration or biopsy. The passage comprises a longitudinal slot converging from end to end and a transverse slot extending laterally for the entire length of the longitudinal slot from the longitudinal slot to the side surface of the array.

Abstract: In order to obviate the necessity for providing a complete channel of electronics for each transducer of an array incorporated into a real-time ultrasonic imaging system, all system transducers are disposed in apparent series with a single inductor as to direct current. Charging resistors permit each transducer to slowly capacitively charge to a predetermined voltage under static conditions. When a switching transistor disposed in series with a given transducer is placed in the conducting state, the transducer rapidly discharges and mechanically deflects to introduce an ultrasonic pulse into an object. While the switching transistor remains conductive, the inductor and transducer are in parallel circuit as to echo signals returning to the transducer. When the switching transistor is rendered non-conductive, the transducer again charges capacitively in anticipation of a succeeding cycle.

Abstract: A piezoelectric crystal has a concave active surface and a high acoustical impedance. A flat layer of molded material having a low acoustical impedance faces the active surface of the crystal to form a space therebetween. An intermediate layer of molded material having an intermediate acoustical impedance fills the space between the crystal and the flat layer. Preferably, the intermediate material has a sonic velocity near that of water, and the flat layer has a uniform thickness of approximately 1/4 of the average wavelength of the ultrasonic energy emitted by the crystal. A housing supports the crystal, the flat layer, and the intermediate layer.