Curvilinear interleaved longitudinal-mode ultrasound transducers

An ultrasound transducer comprising:

• a substrate of piezoelectric material, said substrate having a front surface and a back surface, said substrate being alternately poled in a thickness dimension extending from said back surface toward said front surface;
• a radially extending series of substantially parallel curvilinear electrode segments, each of said electrode segments subtending an angle of at least 270.degree. about a central point, said electrode segments being disposed on said back surface, each pair of electrode segments having an odd number of electrode segments between them being shorted together;
• and
• interface means for acoustically coupling said substrate with said body, said interface means being in contact with at least one of said front and back surfaces.

An ultrasound transducer for acoustically examining a body, said transducer comprising:

• a substrate of piezoelectric material, said substrate having a front surface and a back surface, said substrate being alternately poled in a thickness dimension extending from said back surface toward said front surface;
• a radially extending series of substantially parallel curvilinear electrode segments, each of said electrode segments subtending an angle of at least 270.degree. about a central point, said electrode segments being disposed on said back surface;
• interface means for acoustically coupling said substrate with said body, said interface means being in contact with at least one of said front and back surfaces;
• and
• means for commonly driving a subseries of said electrode segments, said subseries being selected so that no two electrode segments of said subseries are radially adjacent and so that no two electrode segments of said series and not in said subseries are radially adjacent.

A transducer for acoustically examining a body, said transducer comprising:

• piezoelectric means for converting electrical energy into acoustic energy and vice-versa, said piezoelectric means having an array of electrode sites, said piezoelectric means being alternately poled in a thickness direction at each of said sites;
• an array of electrode pairs, each electrode pair being disposed at a respective one of said electrode sites, each electrode pair having a radially extending series of parallel curvilinear segments, each of said electrode segments subtending an angle of at least 270.degree. about a central point of the respective electrode pair, each said series containing first and second subseries of electrode segments, said first and second subseries alternating so that one electrode segment of said first subseries is positioned radially between a consecutive pair of electrode segments of said second subseries, and so that one electrode segment of said second series is positioned radially between each consecutive pair of electrode segments of said first subseries;
• steering means for determining a wavefront direction, said steering means being electrically coupled to each of said electrode pairs for determining relative delays between said electrode pairs;
• and
• interface means for acoustically coupling said piezoelectric means to said body, said interface means being in contact with said piezoelectric means.