A multi-layer microactuator for a hard disk drive suspension includes a piezoelectric (PZT) layer, a constraining layer, a lower electrode layer, a middle electrode layer, and an upper electrode layer. The lower electrode layer is on a bottom surface of the PZT layer and includes a first lower electrode island, a second lower electrode island, and a third lower electrode island. The second lower electrode island includes a finger extending from a main body portion towards a first end of the PZT layer. The middle electrode layer is disposed between a top surface of the PZT layer and a bottom surface of the constraining layer. The middle electrode layer including a first middle electrode island and a second middle electrode island, the second middle electrode island including a finger extending from a main body portion towards the first end of the PZT layer.

An elastomer piezoelectric element is configured by alternately disposing first opposite electrodes and second opposite electrodes, and sandwiching a dielectric layer between each first opposite electrode and the corresponding second opposite electrode. Each of the dielectric layers includes a dielectric elastomer sheet-shaped dielectric portion and a conductive elastomer first common electrode connecting the first opposite electrodes to each other or a conductive elastomer second common electrode connecting the second opposite electrodes to each other. The first common electrode and the second common electrode are provided so as to extend from one main surface to another main surface of the dielectric portion, and are joined to the first opposite electrode and the second opposite electrode, respectively, on a joint surface along the dielectric layer.

A vibrating device includes a diaphragm, a piezoelectric element, and a wiring board. The piezoelectric element and the wiring board are bonded to a first principal plane of the diaphragm. The wiring board is electrically connected with the piezoelectric element. The piezoelectric element includes a piezoelectric element body, a plurality of internal electrodes, and a plurality of external electrodes. The piezoelectric element body has a second principal plane, a third principal plane, and a side surface. The third principal plane and the side surface are bonded to the first principal plane. The wiring board has a resin film, a plurality of conductors, and a coating film. The coating film is disposed on the plurality of conductors in such a way as to cover the plurality of conductors. One end portions of the plurality of conductors are exposed from the coating film and electrically connected with corresponding external electrodes.

An actuator device has an electroactive polymer actuator (35) and an integrated piezoelectric transformer (30) whose primary side (32) and secondary side (34) are formed from different electroactive polymer materials. At least the secondary side (34) of the transformer shares a piezoelectric electroactive polymer layer (36) with the electroactive polymer actuator, so that lower external voltages can be applied to the device.

In a piezoelectric element, shift of a resonance point to a low-pitched sound side is achieved. A resonance point of a piezoelectric element moves to a low-pitched sound side when an active region is configured to be surrounded by an inactive region as in the configuration of the piezoelectric element. According to the piezoelectric element whose resonance point is moved to a low-pitched sound side, the piezoelectric element can realize a sound pressure that is sufficiently high for practical use when it is applied to an acoustic device.

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.1xyNbO.sub.3 (where 0.02<x0.1, 0.02<x+y1) 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 multilayer piezoelectric ceramic is such that: its piezoelectric ceramic layers do not contain lead as a constituent element, and have a perovskite compound expressed by the composition formula Li.sub.xNa.sub.yK.sub.1-x-yNbO.sub.3 (where 0.02<0.1, 0.02<x+y1), as the primary component; and the internal electrode layers are constituted by a metal containing silver by 80 percent by mass or more, and contain ceramic grains containing the same elements found in the primary component. The multilayer piezoelectric element has a long lifespan, and whose internal electrode layers have a high content percentage of silver.

A piezoelectric element includes a piezoelectric element body including a first principal surface and a second principal surface opposing each other, and a plurality of external electrodes disposed on the first principal surface. A vibration member includes a third principal surface opposing the second principal surface. The piezoelectric element is joined to the third principal surface. A wiring member is electrically connected to the piezoelectric element. The wiring member includes a region located on the plurality of external electrodes and joined to the plurality of external electrodes. The region of the wiring member monolithically covers the plurality of external electrodes when viewed from a direction orthogonal to the first principal surface.

A piezoelectric element includes first and second electrodes, a first piezoelectric body layer, and a plurality of first through-hole conductors. The first and second electrodes oppose each other. The first piezoelectric body layer is disposed between the first electrode and the second electrode. The plurality of first through-hole conductors penetrates the first piezoelectric body layer and is connected to the first electrode and the second electrode. When seen in an opposing direction of the first and second electrodes, the plurality of first through-hole conductors is arrayed in a matrix.

A multi-layer microactuator for a hard disk drive suspension includes a piezoelectric (PZT) layer, a constraining layer, a lower electrode layer, a middle electrode layer, and an upper electrode layer. The lower electrode layer is on a bottom surface of the PZT layer and includes a first lower electrode island, a second lower electrode island, and a third lower electrode island. The second lower electrode island includes a finger extending from a main body portion towards a first end of the PZT layer. The middle electrode layer is disposed between a top surface of the PZT layer and a bottom surface of the constraining layer. The middle electrode layer including a first middle electrode island and a second middle electrode island, the second middle electrode island including a finger extending from a main body portion towards the first end of the PZT layer.