A piezoelectric element includes: a first electrode provided on a base; a second electrode; and a piezoelectric layer that is provided between the first electrode and the second electrode and that contains a complex oxide having a perovskite structure and including potassium, sodium, and niobium, where: a surface of the piezoelectric layer on a side of the second electrode is composed of faces of first grains and faces of second grains; a roughness height on the faces of the first grains is larger than a roughness height on the faces of the second grains; and an area occupied by the faces of the first grains is 10.0% or less on the surface of the piezoelectric layer.

The piezoelectric element comprises a piezoelectric body extending in a lateral direction and a first and second electrodes that are provided on the piezoelectric body. The piezoelectric body has an active portion sandwiched between the first and second electrodes in a thickness direction that is vertical to the lateral direction, and an inactive portion connected to the active portion in the lateral direction. The first electrode has an active electrode portion disposed on the active portion. The active electrode portion includes an interface region that is adjacent to the interface of the active portion and the inactive portion in the lateral direction, and an inner region that is separated from the interface of the active portion and the inactive portion in the lateral direction. The cross sectional surface area per unit length of the interface region in the cross section of the active electrode portion is greater than the cross sectional area per unit length of the inner region.

A multilayer piezoelectric element includes a laminated body and a lateral electrode. The laminated body includes a piezoelectric layer, an internal electrode layer, and a dummy electrode layer. The piezoelectric layer is formed along a plane including a first axis and a second axis perpendicular to each other. The internal electrode layer and the dummy electrode layer are laminated on the piezoelectric layer. The lateral electrode is formed on a lateral surface of the laminated body perpendicular to the first axis. The internal electrode layer has a leading portion exposed to the lateral surface of the laminated body and is electrically connected with the lateral electrode via the leading portion. The dummy electrode layer is formed on the plane to surround the internal electrode layer excluding the leading portion with a gap therebetween. A slit is formed at least at one or more positions of the dummy electrode layer.

A method of fabricating pre-structured functional wafers, pre-structured functional cuboid or wafer stack, and a method of fabricating an array of functional multilayer stack actuators made of relaxor ferroelectric single crystal piezoelectric thin layers comprising sequentially repeated steps of wafer dicing and trench refilling into relatively thick wafer(s). A bulk-micromachined dimensioned deformable mirror device comprising a base supporting substrate, a plurality of stack actuators that is made by segmenting a pre-structured relaxor ferroelectric single crystal piezoelectric cuboid or wafer stack, a plurality of pedestals disposed on the plurality of stack actuators; a deformable membrane mirror mounted on said pedestals; and a plurality of addressable electrode contacts.

A piezoelectric bimorph cantilever beam system includes a shim having a first main surface, a second main surface opposite the first main surface, a proximal end connected to an anchor, and a distal end opposite the proximal end. The system further includes a first piezoelectric layer laminated on the first main surface of the shim and a second piezoelectric layer laminated on the second main surface of the shim. A first beam stiffener is provided over the first main surface of the shim adjacent to the anchor with the first beam stiffener at least partially covering the first piezoelectric layer. A second beam stiffener is provided over the second main surface of the shim adjacent to the anchor with the second beam stiffener at least partially covering the second piezoelectric layer.

In a method of manufacturing a piezoelectric device, during an isolation formation step, a supporting substrate has a piezoelectric thin film formed on its front with a compressive stress film present on its back. The compressive stress film compresses the surface on a piezoelectric single crystal substrate side of the supporting substrate, and the piezoelectric thin film compresses the back of the supporting substrate, which is opposite to the surface on the piezoelectric single crystal substrate side. Thus, the compressive stress produced by the compressive stress film and that produced by the piezoelectric thin film are balanced in the supporting substrate, which causes the supporting substrate to be free of warpage and remain flat. A driving force that induces isolation in the isolation formation step is gasification of the implanted ionized element rather than the compressive stress to the isolation plane produced by the piezoelectric thin film.

In a piezoelectric element, internal stress generated in an inactive portion at the time of sintering when a piezoelectric element is fabricated or stress applied from the outside to the inactive portion is absorbed by a recess of a lower surface of a first through hole conductor and a recess of an upper surface of a second through hole conductor. Accordingly, for example, deformation, rupture, or the like of the through hole conductor is prevented, and conduction failure or disconnection of an electrode layer or a through hole conductor is prevented. Further, in the inactive portion, since a protrusion of the piezoelectric layer enters the recess of the through hole conductor, a holding force of the piezoelectric layer with respect to the through hole conductor increases, and deformation of the through hole conductor is prevented or obstructed.

Provided is a method for inspecting a piezoelectric element in which voltage is applied to a piezoelectric element and evaluation of the electrical characteristics of the piezoelectric element is performed. The method includes a first step in which the piezoelectric element is held on a flat plate-shaped slightly adhesive sheet and a second step in which voltage is applied to the piezoelectric element held on the slightly adhesive sheet and evaluation of the electrical characteristics of the piezoelectric element is performed.

A piezoelectric element includes a piezoelectric body layer, a first electrode, a second electrode, a third electrode, and a conductor. The piezoelectric body layer has rectangular first and second principal surfaces opposing each other, and includes a piezoelectric material. The first electrode is provided on the first principal surface. The second electrode is provided on the first principal surface in such a way that the second electrode is separated from the first electrode. The third electrode is provided on the second principal surface in such a way that the third electrode opposes the first electrode. The conductor is connected to the second electrode and the third electrode. The first electrode has a round corner being rounder than a corner part of the piezoelectric body layer when seen in an opposing direction of the first and second principal surfaces.

Provided is a method for producing a piezoelectric element in which a piezoelectric body substrate piece is subjected to polarization treatment and a piezoelectric element is produced. The method includes a first step in which the piezoelectric body substrate piece is held on a flat plate-shaped slightly adhesive sheet and a second step in which voltage is applied to the piezoelectric body substrate piece held on the slightly adhesive sheet and the piezoelectric body substrate piece is subjected to polarization treatment.