Electroacoustic device that includes a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode. The body includes a piezoelectric part or the electroacoustic device further including a piezoelectric part different from the body. The hot electrode includes a hot track spiraling around a spiral axis. The radial step between two consecutive coils of the hot track decreasing radially from the spiral axis. The hot electrode and the ground electrode are arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in the fluid medium.

Some embodiments relate to an energy transduction device or apparatus. An example device or apparatus includes: a piezoelectric transducer; electrical conductors electrically coupled to the piezoelectric transducer; and an axially aligned magnet assembly arranged to apply static compressive force to the piezoelectric transducer, the magnet assembly being coupled to a base at one end and having a free opposite end. The magnet assembly is coaxial with the piezoelectric transducer and at least part of the magnet assembly is concentric with the piezoelectric transducer. The magnet assembly defines a gap between axially adjacent parts of the magnet assembly, wherein the gap is dimensioned to be sufficiently small that the magnet assembly applies a static compressive force to the piezoelectric transducer while being sufficiently large to allow for axial movement of the piezoelectric transducer without closing the gap.

The present invention is a piezoelectric actuator drive method, a piezoelectric actuator drive circuit, and a piezoelectric actuator drive system capable of causing a piezoelectric element to vibrate in a maximum amplitude state. The piezoelectric actuator drive circuit includes: an obtainment unit that obtains operation information pertaining to operation of the piezoelectric element in a period that is a part of one cycle of a drive cycle in which the piezoelectric element is driven; and a control unit that performs feedback control of a drive parameter for driving the piezoelectric element based on the operation information.

A vibration type motor has a vibrator; a frictional member, a pressurization unit that causes the vibrator and the frictional member to come into pressure-contact with each other, a retaining member that retains the frictional member, and a fixing unit that fixes the friction member to the retaining member, and the vibrator and the frictional member make relative movement by the vibrator being vibrated. The frictional member has a first area including an area that contacts the vibrator and a second area including an area that is retained by the retaining member. A size of the first area in an orthogonal direction that is orthogonal to both the direction of the relative movement and a pressure direction of the pressurization unit is smaller than a size of the second area in the orthogonal direction.

Method comprising: supplying electricity to at least one wave transducer (25) for synthesising an ultrasonic surface wave propagating in a medium (10) to a body (15) arranged on one side of the medium, at least one portion of the electrical supply energy being converted into heat by the transducer, the electrical energy supplied to the transducer being sufficient for the heat and the energy of the ultrasonic surface wave to cause: —the body to melt when the body is in the solid state, and/or—the body to be maintained in the liquid state when the temperature of the medium is below the solidification temperature of the body.

A vibration device includes a semiconductor substrate having a first surface and a second surface in an obverse-reverse relationship, a vibration element disposed on the first surface, a lid bonded to the first surface, an integrated circuit disposed on the first surface, a terminal disposed on the second surface, a through electrode which penetrates the semiconductor substrate, and is configured to electrically couple the terminal and the integrated circuit to each other, and a first capacitor which is provided with a first recess provided to the semiconductor substrate and opening in the first surface, an insulating film disposed on an inside surface of the first recess, and an electrically-conductive material filling the first recess, and has a first capacitance between the electrically-conductive material and the semiconductor substrate, wherein the electrically-conductive material does not have contact with the terminal at the second surface side.

A vibration apparatus may include a vibration generator including a piezoelectric material and a sensor portion configured at the vibration generator, and thus, may correct or compensate for an electrical characteristic change of the vibration generator and may correct or compensate for a vibration characteristic of the vibration generator. An apparatus including the vibration apparatus is also disclosed.

An ultrasonic sensor includes a casing and a piezoelectric vibrator element. The casing includes a first unit made of a metal and a second unit made of a resin. The first unit has a cylindrical or substantially cylindrical shape extending in a first direction. The second unit is connected to one end of the first unit in the first direction and includes a cylindrical section and a bottom plate. The cylindrical section extends in the first direction. The bottom plate is a disk-shaped portion which closes an end of the cylindrical section positioned farther away from the first unit in the first direction. The piezoelectric vibrator element is mounted on the bottom plate.

A method for removing foreign substances from a camera system is provided. The camera system includes a camera device with a transparent cover having a piezoelectric component. First, a type of the foreign substances is identified based on temperature, an image captured by the camera system, and a voltage change of the piezoelectric component. A sequence of frequencies is applied to the piezoelectric component and a resonant frequency is acquired. Thereafter, the foreign substances are removed from the camera system. A vibration frequency and a vibration time period for the piezoelectric component are determined according to the identified type of the foreign substances. The vibration frequency is based on the resonant frequency. The piezoelectric component is driven with the vibration frequency and the vibration time period, such that at least a portion of the foreign substances are removed from the transparent cover through vibration of the piezoelectric component.

A vibration generating device 90 includes: a housing 30 in a rectangular shape as viewed in a first direction, the housing 30 comprising: a first support portion 31 extending along a first side in a second direction perpendicular to the first direction and; a second support portion 32 extending along a second side opposite to the first side in the second direction; a panel 60 supported by the first support portion and the second support portion; and a piezoelectric element 11 attached to the panel in such a manner as to be shifted in the second direction toward the first side with respect to a central portion of the panel, wherein a width in the second direction of a portion of the panel supported by the first support portion is larger than a width in the second direction of a portion of the panel supported by the second support portion.