A vibration generating device 10 includes: a diaphragm 11; and a first piezoelectric actuator 12 and a second piezoelectric actuator 13 attached on an upper surface 11a and a lower surface 11b of the diaphragm 11, respectively, so as to sandwich the diaphragm 11 therebetween in a vicinity of an end surface of the diaphragm 11, wherein, in a top view of the upper surface 11a of the diaphragm 11, the first piezoelectric actuator 12 is disposed at a position shifted with respect to the second piezoelectric actuator 13.

A sensor is disclosed which includes a piezoelectric layer, a piezoresistive layer, one or more electrode layers coupled to the piezoelectric layer and to the piezoresistive layer, the piezoelectric layer configured to provide an electrical signal in response to application of a dynamic disturbance, and the piezoresistive layer configured to provide a change in resistivity in response to application of a static disturbance.

A piezoelectric ceramic transducer includes a tubular body and a metal electrode unit. The tubular body is made of a piezoelectric ceramic material, and includes an inner surrounding surface surrounding an extending central axis thereof and defining an axial through hole, an outer surrounding surface surrounding the inner surrounding surface, and a connecting surface connected between the inner surrounding surface and the outer surrounding surface. Any tangent plane of the connecting surface of the tubular body is not perpendicular to the extending central axis. The metal electrode unit includes a first layer formed on the inner surrounding surface, and a second layer formed on the outer surrounding surface.

A vibration apparatus includes a vibration device. The vibration device includes a vibration portion including a piezoelectric material, a first electrode portion at a first surface of the vibration portion and configured as a plurality of circular patterns, and a second electrode portion at a second surface different from the first surface of the vibration portion and configured as a single electrode, and the vibration device generates an ultrasound wave.

A method of making an acoustic sensor (e.g., a piezoelectric sensor for a piezoelectric microelectromechanical systems microphone) includes forming or depositing one or more piezoelectric layers to define a beam extending between a proximal portion and a distal tip (e.g., unsupported free end), the beam having a width in plan view that is greater at a location distal of the proximal portion than at the proximal portion. The method also comprises attaching the beam to a substrate in cantilever form so that the proximal portion of the beam is anchored to the substrate and the distal tip is a free unsupported end of the beam. One or more electrodes are disposed on or in the proximal portion of the beam.

A piezoelectric device including a substrate, a metal-insulator-metal element, a hydrogen blocking layer, a passivation layer, a first contact terminal and a second contact terminal is provided. The metal-insulator-metal element is disposed on the substrate. The hydrogen blocking layer is disposed on the metal-insulator-metal element. The passivation layer covers the hydrogen blocking layer and the metal-insulator-metal element. The first contact terminal is electrically connected to the metal-insulator-metal element. The second contact terminal is electrically connected to the metal-insulator-metal element.

A microphone device may include: a substrate wafer, a support member bonded to a front surface of the substrate wafer, a single-crystal piezoelectric film provided over the support member, a top electrode and a bottom electrode. The single-crystal piezoelectric film may have a first surface and an opposing second surface. The top electrode may be arranged adjacent to the first surface of the single-crystal piezoelectric film. The bottom electrode may be arranged adjacent to the second surface of the single-crystal piezoelectric film. The substrate wafer may have a through-hole formed therein. The through-hole of the substrate wafer may be at least substantially aligned with at least one of the top electrode and the bottom electrode.

Provided is a piezoelectric ceramics having a gradual change in piezoelectric constant depending on an ambient temperature. Specifically, provided is a single-piece piezoelectric ceramics including as a main component a perovskite-type metal oxide represented by a compositional formula of ABO.sub.3, wherein an A site element in the compositional formula contains Ba and M.sub.1, the M.sub.1 being formed of at least one kind selected from the group consisting of Ca and Bi, wherein a B site element in the compositional formula contains T1 and M.sub.2, the M.sub.2 being formed of at least one kind selected from the group consisting of Zr, Sn, and Hf, wherein concentrations of the M.sub.1 and the M.sub.2 change in at least one direction of the piezoelectric ceramics, and wherein increase and decrease directions of concentration changes of the M.sub.1 and the M.sub.2 are directions opposite to each other.

An optical element includes a primary electrode, a secondary electrode overlapping at least a portion of the primary electrode, and an electrostrictive ceramic layer disposed between and abutting the primary electrode and the secondary electrode, where the electrostrictive ceramic may be characterized by a relative density of at least approximately 99%, an average grain size of at least approximately 300 nm, a transmissivity within the visible spectrum of at least approximately 70%, and bulk haze of less than approximately 10%. Optical properties of the electrostrictive ceramic may be substantially unchanged during the application of a voltage to the electrostrictive ceramic layer and the attendant actuation of the optical element.

A multilayer piezoelectric element includes a piezoelectric body containing a piezoelectric ceramic material, a first electrode, and a second electrode. The piezoelectric body includes a first main surface and a second main surface opposing each other. The first electrode includes an external electrode formed on the first main surface. The second electrode includes an internal electrode formed inside the piezoelectric body to oppose the external electrode. The piezoelectric body includes an active region between the external electrode and the internal electrode, and includes an inactive region opposite to the active region with the internal electrode interposed therebetween. A stress received by the piezoelectric body from the external electrode is larger than a stress received by the piezoelectric body from the internal electrode. A polarization direction of the active region is a direction directed from the external electrode to the internal electrode.