A multilayer piezoelectric ceramic is constituted by: piezoelectric ceramic layers which do not contain lead as a constituent element, have a perovskite compound expressed by the composition formula Li.sub.xNa.sub.yK.sub.1−x−yNbO.sub.3 (where 0.02<x≤0.1, 0.02<x+y≤1) as the primary component, and contain 0.2 to 3.0 mol of Li relative to 100 mol of the primary component; and internal electrode layers which are constituted by a metal that contains silver by 80 percent by mass or more; wherein the multilayer piezoelectric ceramic is such that Li compounds other than the primary component are localized therein. The multilayer piezoelectric element can offer excellent insulating property.

A plurality of conductive via connections are fabricated on a substrate located at positions where MTJ devices are to be fabricated, wherein a width of each of the conductive via connections is smaller than or equivalent to a width of the MTJ devices. The conductive via connections are surrounded with a dielectric layer having a height sufficient to ensure that at the end of a main MTJ etch, an etch front remains in the dielectric layer surrounding the conductive via connections. Thereafter, a MTJ film stack is deposited on the plurality of conductive via connections surrounded by the dielectric layer. The MTJ film stack is etched using an ion beam etch process (IBE), etching through the MTJ film stack and into the dielectric layer surrounding the conductive via connections to form the MTJ devices wherein by etching into the dielectric layer, re-deposition on sidewalls of the MTJ devices is insulating.

An interventional device includes an elongate shaft and a transducer strip. The transducer strip includes a first edge and an opposing second edge. The first edge and the second edge are separated by a width dimension, and the first edge and the second edge each extend along a length direction of the transducer strip. The transducer strip also includes a piezoelectric transducer that extends along a transducer direction that forms an acute angle with respect to the length direction. The transducer strip is wrapped in the form of a spiral around the elongate shaft of the interventional device such that the piezoelectric transducer forms a band around the elongate shaft. The width dimension is defined such that the adjacent first and second edges of consecutive turns of the spiral abut or overlap one another.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

A sensing film includes a base layer, a piezoelectric layer formed on the base layer, and a first electrode and a second electrode formed on the piezoelectric layer. The first and second electrodes are spaced apart and electrically insulated from each other. The first electrode includes a first connecting portion and a number of first extending portions coupled to the first connecting portion. The second electrode includes a second connecting portion and a number of second extending portions coupled to the second connecting portion. The first connecting portion and the second connecting portion are spaced apart and face each other. The first extending portions extend from a side of the first connecting portion toward the second connecting portion. The second extending portions extend from a side of the second connecting portion toward the first connecting portion. The first extending portions and the second extending portions are alternately arranged.

A current introduction terminal includes a board made of resin. The board has a first face and a second face opposite each other. The board hermetically separates environments of different air pressures from each other. A plurality of through via holes corresponding both to a plurality of metal terminals of a first surface-mount connector to be mounted on the first face and to a plurality of metal terminals of a second surface-mount connector to be mounted on the second face are formed to penetrate between the first and second faces, and then hole parts of the through via holes are filled with resin.

A piezoelectric actuator 10 includes: a piezoelectric element 11; an external electrode 12 covering partially a first surface 11a of the piezoelectric element 11 in a first direction; a wiring member 14; and a conductive joining member 20 joining the wiring member 14 to the external electrode 12, wherein the conductive joining member 20 has an air gap 70 formed between the external electrode 12 and the wiring member 14 in a region overlapping with the wiring member 14 as viewed in the first direction, and wherein the conductive joining member 20 extends to an edge 21 of the external electrode 12 or extends to the first surface 11a of the piezoelectric element 11 beyond the edge 21 of the external electrode 12.

A PMUT ultrasound transducer includes a number of PMUT transmitting elements in a membrane layer. Behind each PMUT transmitting element is a cavity in the membrane layer. The cavities are partially or completely filled with a damping material to reduce ringing of the PMUT transmitting elements. Suitable damping materials include polymers, e.g., soft epoxies, benzocyclobutene or polyimide that are dispersed into the cavities or a phase changing material such as Parylene that precipitates out of a gas phase as a polymer when cured.

Disclosed herein is a transparent ultrasonic sensor including a matching unit configured to perform optical impedance matching and formed of a transparent material, a piezoelectric layer positioned behind the matching unit and formed of a transparent material, a first electrode layer and a second electrode layer positioned on a rear surface and a front surface of the piezoelectric layer, respectively, the first electrode layer and the second electrode layer being formed of a transparent conductive material, a first housing connected to the first electrode layer, and a second housing connected to the second electrode layer.

An ultrasonic device, comprising an ultrasonic transducer (400) comprising: a membrane (405) suspended above a cavity (403) arranged on the upper surface side of a substrate (401); a piezoelectric layer (407) attached to a surface of the membrane (405); a first electrode (E1) arranged on the lower surface side of the cavity (403); and a second electrode (E3) arranged on the upper surface side of the cavity (403), in contact with the piezoelectric layer (407), the device further comprising a control circuit (CTRL) connected to the first (E1) and second (E3) electrodes and capable of applying a first control voltage (VDC) on the first electrode (E1), and a second control voltage (VAC) different from the first voltage on the second electrode (E3).