A piezoelectric actuator includes an electrode layer including a trunk portion and a plurality of branch portions branched from the trunk portion. The trunk portion includes a plurality of junction points from each of which a corresponding branch portion of the plurality of branch portions are branched, an end spaced from the plurality of junction points, and a second through hole positioned between the plurality of junction points and the end of the trunk portion. A plurality of first through holes are grouped into a first group and a second group. The first group overlaps, in a first direction, a particular area defined between the end of the trunk portion and the second through hole and the second group overlaps, in the first direction, another particular area defined between the second through hole and the plurality of junction points.

An electromechanical device comprising: first and second electrodes each comprising a metal layer; an active layer comprising at least one ferroelectric polymer and disposed between the first and the second electrode. The first electrode and the second electrode each comprise an interface layer comprising poly(3,4-ethylenedioxythiophene). Each interface layer is interposed between the active layer and the corresponding metal layer. The invention further relates to a method for manufacturing such a device.

Microelectromechanical System (MEMS) devices and related fabrication methods. A piezoelectric stack is formed on a substrate and is separated from the substrate by a dielectric layer. The piezoelectric stack is formed that includes first and second piezoelectric layers with a first electrode below the first piezoelectric layer, as well as a contact pad and a second electrode between the first and second piezoelectric layers. A first contact is formed that extends through the piezoelectric layers and contact pad to the first electrode. A second contact is formed that extends through the second piezoelectric layer to the second electrode. The contact pad prevents an interface to form between the first and second piezoelectric layers in the contact opening, thus preventing corrosion of the piezoelectric layers during contact formation process.

A device having a piezoelectric actuator, which can both detect the actuation force and provide a haptic feedback. The linear expansion of the actuator can be amplified in the desired direction by a deformable metal sheet. The actuator has a flat piezoelectric basic body having plane-parallel main surfaces and two electrodes. The body is designed to generate an active haptic feedback when a force exerted upon the basic body is detected. The haptic feedback is generated in that an actuator voltage, which, by piezoelectric actuator action, results in a change in the length of the basic body, is applied between the electrodes. A cymbal-shaped metal sheet is fastened to the basic body. The body is fixed with the truncated cone vertices between a base and an actuation means connected to the base and fixed by means of a bias, which is set as tensile or compressive stress.

A piezoelectric element includes a piezoelectric body, an electrode layer, and a reinforcing layer. The piezoelectric body has a first main surface, a second main surface, and a side surface. The first main surface and the second main surface oppose each other. The side surface extends in an opposing direction in which the first main surface and the second main surface oppose each other in such a way as to connect the first main surface and the second main surface. The electrode layer is provided in the piezoelectric body. The reinforcing layer is provided on the first main surface. The electrode layer is provided opposing the first main surface and apart from the side surface. When viewed from the opposing direction, the electrode layer has a corner. When viewed from the opposing direction, the reinforcing layer overlaps the corner.

A piezoelectric module includes an element substrate that includes a plurality of piezoelectric bodies (piezoelectric elements) arranged in an array, and a plurality of connection electrodes (lower connection electrode and upper connection electrode) that are connected to the piezoelectric body (piezoelectric element) and are drawn between the piezoelectric body (piezoelectric element) and an adjacent piezoelectric body (piezoelectric element), an input and output circuit that is provided on one surface side of the element substrate and independently inputs and outputs a signal from and to each of the connection electrodes (lower connection electrode and upper connection electrode), and columnar electrodes (first through electrode and second through electrode) each of which is provided between each of the connection electrodes (lower connection electrode and upper connection electrode) and the input and output circuit and connects each of the connection electrodes (lower connection electrode and upper connection electrode) and the input and output circuit to each other.

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.

A vibration device includes a piezoelectric element, a vibration member to which the piezoelectric element is bonded, and a wiring member connected with the piezoelectric element. A method for vibrating the vibration device includes inputting a signal including a fundamental frequency component to the piezoelectric element through the wiring member, and vibrating the vibration device in a vibration mode that includes the fundamental frequency component and does not approximately include a high order frequency component that is n times (n represents an integer of 2 or more) the fundamental frequency component. The fundamental frequency component is lower than the resonance frequency component of the vibration device.

An actuator device has an electroactive polymer actuator (35) and an integrated piezoelectric transformer (30). 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. A diode (46) is connected between the secondary side of the transformer and the electroactive polymer actuator.

A multilayer piezoelectric element includes a piezoelectric element body, a first internal electrode and a second internal electrode, a plurality of first connecting conductors, a plurality of second connecting conductors, and an external member. The piezoelectric element body is formed by laminating a plurality of piezoelectric element body layer. The piezoelectric element body includes a first main surface and a second main surface, and a side surface. The plurality of first connecting conductors are connected to the first internal electrode. The plurality of second connecting conductors are connected to the second internal electrode. The external member is conductive and is bonded to the first main surface in such a way as to cover the first end portions of the plurality of first connecting conductors. The external member is electrically connected to the plurality of first connecting conductors.