An omnidirectional electroacoustic transducer capable of reproducing a sound with high acoustic quality and sufficient sound volume in a wide frequency band is provided with a small number of components. The electroacoustic transducer includes: two or more electroacoustic transduction units each including an electroacoustic transduction film and an elastic supporter, the electroacoustic transduction film having a polymer composite piezoelectric body in which piezoelectric body particles are dispersed in a viscoelastic matrix formed of a polymer material having viscoelasticity at a normal temperature, and two thin film electrodes laminated on both surfaces of the polymer composite piezoelectric body, and the elastic supporter being disposed to be closely attached to one principal surface of the electroacoustic transduction film so as to cause the electroacoustic transduction film to be bent, in which the two or more electroacoustic transduction units are disposed so that the electroacoustic transduction films face outward and form some or all of faces of a polyhedron.

Embodiments described herein include a resonant process monitor and methods of forming such a resonant process monitor. In an embodiment, the resonant process monitor includes a frame that has a first opening and a second opening. In an embodiment, a resonant body seals the first opening of the frame. In an embodiment, a first electrode on a first surface of the resonant body contacts the frame and a second electrode is on a second surface of the resonant body. Embodiments also include a back plate that seals the second opening of the frame. In an embodiment the back plate is mechanically coupled to the frame, and the resonant body, the back plate, and interior surfaces of the frame define a cavity.

Disclosed is a sound vibration sensor using a piezoelectric element having a cantilever structure. The sound vibration sensor includes a housing forming an exterior, a piezoelectric element having a cantilever structure installed in the housing, a support structure supporting a fixed end of the piezoelectric element, a weight attached to a free end of the piezoelectric element, and an energizing part configured to transmit an output from the piezoelectric element, wherein the sound vibration sensor comes into contact with a speaker's body, receives vibration of the body generated when the speaker utters a sound through the housing, and amplifies the vibration by the free end of the piezoelectric element to detect the voice vibration of the speaker using a piezoelectric characteristic of the piezoelectric element.

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.

A foil transducer for a valve, including at least one firmly arranged holding part, at least one displaceable force transmission part, an electroactive foil composite structure and at least two electrodes. The electroactive foil composite structure has an actuating direction in which the electroactive foil composite structure is extended on actuation. The actuating direction lies in a plane spanned by the electroactive foil composite structure.

A piezoelectric transformer comprises at least a laminate of a first member, a first piezoelectric element, a second piezoelectric element and a second member sequentially stacked one on the other in the above-listed order and a pressurizing mechanism for squeezing the first member and the second member together in the stacking direction. The ratio of the electromechanical coupling coefficient k.sub.33 relative to the electromechanical coupling coefficient k.sub.31 (k.sub.33/k.sub.31) of the first piezoelectric element and the second piezoelectric element is not less than 2.0.

An electromagnetic-piezoelectric composite vibration control device based on a synchronized switch damping technology is provided. An upper guiding component is installed inside the upper rigid frame, a lower guiding component is installed inside a lower rigid component, a guide rod is nested inside the upper guiding component and the lower guiding component, an upper idler wheel mechanism and a lower idler wheel mechanism are fixedly sleeved on the guide rod and are positioned between the upper guiding component and the lower guiding component respectively, an electromagnetic mechanism is fixedly sleeved outside the guide rod, one end of each piezoelectric cantilever beam is fixed between the upper rigid frame and the lower rigid frame, the other end is arranged between the upper idler wheel mechanism and the lower idler wheel mechanism, and the piezoelectric cantilever beams and the electromagnetic mechanism are connected with a circuit system respectively.

A displacement magnification device has a first link portion including a first rigid body and a first plate spring that couples the first rigid body to a supporting portion and a movable portion. A second link portion includes a second rigid body and a second plate spring that couples the second rigid body to the supporting portion and the movable portion. In this structure, the first rigid body and the second rigid body play roles to suppress the bending of the first plate spring and the second plate spring. In addition, a connection portion between the first plate spring and the supporting portion, a connection portion between the second plate spring and the supporting portion, a connection portion between the first plate spring and the movable portion, and a connection portion between the second plate spring and the movable portion play roles of elastic hinges.

A projection optical system includes a base, a mirror on the base, and a pair of first actuators provided between the base and the mirror, and facing each other. Each of the pair of first actuators includes a first electroactive polymer film having a size that varies according to an applied voltage, and a slope of the mirror is adjusted according to a change in the size of the first electroactive polymer film.

An actuator assembly includes (i) a first actuator stack having a first primary electrode, a first secondary electrode overlapping at least a portion of the first primary electrode, and a first electroactive layer disposed between and abutting the first primary electrode and the first secondary electrode, (ii) a second actuator stack having a second primary electrode, a second secondary electrode overlapping at least a portion of the second primary electrode, and a second electroactive layer disposed between and abutting the second primary electrode and the second secondary electrode; and (iii) a bonding layer disposed between the first actuator stack and the second actuator stack.