Abstract: A method and apparatus for apodization is exemplified in an ultrasound transducer used, for example, in medical applications. The method and apparatus of the present invention provides an ultrasonic transducer with frequency and amplitude apodization, thus improving signal quality and producing improved ultrasonic images. The manufacture of this apparatus is improved by the making of composite cuts into piezoelectric material according to a predetermined pattern which generally varies the concentration of piezoelectric material across the surface of the transducer. Concentration of piezoelectric material can be varied across the surface of the piezoelectric transducer by varying the spacing between the cuts in the piezoelectric material, or by varying the width of the cuts in the piezoelectric material, or a combination of both.

Abstract: A method and apparatus for apodization is exemplified in an ultrasound transducer used, for example, in medical applications. The method and apparatus of the present invention provides an ultrasonic transducer with frequency and amplitude apodization, thus improving signal quality and producing improved ultrasonic images. The manufacture of this apparatus is improved by the making of composite cuts into piezoelectric material according to a predetermined pattern which generally varies the concentration of piezoelectric material across the surface of the transducer. Concentration of piezoelectric material can be varied across the surface of the piezoelectric transducer by varying the spacing between the cuts in the piezoelectric material, or by varying the width of the cuts in the piezoelectric material, or a combination of both.

Abstract: A device for the three-dimensional focusing of an ultrasonic beam, comprising:a phased array (100) has a cylindrical shape with a generatrix X'X, and which comprises M.times.N elementary transducers which are arranged in a curved matrix consisting off M rows extending parallel to X'X and N curved columns extending perpendicularly to said rows.A circuit (200) forms focusing planes P.sub.j which extend through X'X, which circuit is formed by:a multiplexer (201) which selects, for each column i, from the M.times.N signals received by the array (100), the m.sub.o signals S.sub.jk.sup.I supplied by the elementary transducers whose row number is j+k, where K=0, 1, . . . , m.sub.o -1, where m.sub.o is a given number respresenting the aperture width of the ultrasonic beam, and which also forms the sum S.sub.jk.sup.i of the signals S.sub.jk.sup.i and S.sub.jk.sup.i, m.sub.

Abstract: On emission and/or on reception, circuits impose on the signals emitted and/or received, delays in accordance with a random or pseudo-random delay law. On emission, just as on reception, this delay law is superposed on that for focusing and angulation of the signals. On emission, the law is obtained, for example, by causing variation of the instants of triggering of the generators of signals for the excitation of the transducers. On reception, either parallel random delay lines or conditional inversion circuits are included. These circuits permit the breakdown of the coherence of the ultrasonic waves on emission, on reception, or on both simultaneously, may be used in an analogue version, as well as in a digital version.

Abstract: The combined modality device comprises an ultrasound transducer (10) which is suitable for transmission as well as reception and which is connected to a transmitter stage (20) as well as to a receiver stage (30). The transducer (10) has a bandwidth which at least equals approximately one octave. The transmitter stage (20) comprises a generator for generating activation signals for the transducer (10) with a frequency f.sub.o near the lower limit of said bandwidth, the spectrum of these activation signals excluding the frequency f.sub.1 =2f.sub.o. The receiver stage (30) comprises a B-scan channel and also a B/A processing channel (200) which itself includes a bandpass filter (210) which is centered around said frequency f.sub.1, an envelope detector (220, 230), a comparison circuit (240), a differentiation circuit (250) and a display device (260) whereby measured results in both modalities may be displayed.