Abstract: An infra-red imaging device consisting of two sheets of interconnected disks of piezoelectric material, at least one of which has a ferroelectric transition temperature. A metal foil is provided between the sheets and mutually parallel, conductive strips are provided on both outer surfaces of the assembly thus formed, the direction of the strips on the one surface differing from that of the strips on the other surface. A generator for periodic signals which can be sequentially connected to each strip on one of the surfaces of the first sheet generates therein, via a piezoelectric effect, ultrasonic vibrations which are intercepted by the other sheet which converts these vibrations into electric signals. These signals are amplified and carry the image to be examined.

Abstract: A device in which focussed ultrasonic beams are used by way of binary distribution of the phase of the signals occurring in a mosaic of transducers. The material of which the transducers are made can be polarized, which enables the prefocussing of the ultrasonic beam to be transmitted or received, and also enables point-wise scanning and scanning by double focussing according to the X-direction and the Y-direction.

Abstract: A device for ultrasonic examination, comprising a flat mosaic of a row of transmission transducers and a number of rows of receive transducers which are symmetrically arranged with respect thereto. The device furthermore comprises means for applying actuation pulses to one transmission transducer at a time, and means for enabling receive transducers in the time interval following each actuation pulse, and for at the same time displaying on an image display device an image of a section of the examined body in a plane perpendicular to the plane of the mosaic and through the line of transmission transducers.

Abstract: A circuit for continuously recalibrating a gamma camera having a plurality of photomultipliers and signal channels which are weighted to control X and Y deflection on the display. Variation in signal channel gain is controlled and cancelled.