775 results about "Piezoelectric coefficient" patented technology

A piezoelectric device for an ink jet print head that has a greater displacement at a low drive voltage. The ink-jet recording head includes a vibration plate, on which is mounted one or more piezoelectric devices that change the volumes of pressure chambers upon application of a voltage. The device is mounted at least on one face of a pressure chamber substrate that is to be filled with ink. Such piezoelectric device includes a second piezoelectric layer having a piezoelectric constant g of a constant value or higher; and a first piezoelectric layer having a dielectric constant of a specific value or higher. Since the piezoelectric constant d of the piezoelectric device correlates with the product of the largest piezoelectric constant g and the largest dielectric device of the piezoelectric devices, a piezoelectric constant d larger than in the conventional case, i.e., having a greater displacement, can be obtained.

The present subject matter discloses apparatus and methodologies for fabricating apparatus for harvesting power from environmentally induced vibrations. Piezoelectric devices and structures (1600) are disclosed that employ constant force spring or flexure arrangements (1512) in balanced opposition configurations (1510, 1534) to enhance the power harvesting capabilities of the piezoelectric devices (1600). Power harvesting devices and systems in accordance with the subject technology may concurrently operate as sensors in motion sensitive applications thus providing self-powered monitoring capabilities.

The present subject matter discloses devices, systems, and methodologies for harvesting power from environmentally induced vibrations. Piezoelectric devices (24) and structures are disclosed that may be employed in combination with electro-magnetic (100) or capacitive (92, 94) elements to enhance the power harvesting capabilities of the piezoelectric devices (24). The electromagnetic (100) and capacitive (92, 94) elements may be used to assist in maintaining system mechanical resonance in order to maximize energy harvesting capabilities. Power harvesting devices and systems in accordance with the subject technology may concurrently operate as sensors in motion sensitive applications thus providing self-powered monitoring capabilities.

A circuit passively discharges energy from a piezoelectric device and stores the energy in a power storage element. The circuit has two parallel flow paths each including a diode set and an inductor electrically connected to opposite sides of a piezoelectric device. A power storage element is connected to both inductors. The diode sets are alternately forward biased, and energy from the piezoelectric device discharges through the inductor(s). A portion of the energy is stored in the inductor(s) and the remaining portion is stored in the power storage element. The benefits achieved include passive switching between the parallel circuit paths through diodes in place of traditional switches, and the additional energy stored by the inductors which is also transferred to the power storage element. Passive switching conserves additional energy.

The invention relates to the micro-energy field, in particular to a vibratory drive composite micro-power source based on the piezoelectric effect and the electromagnetic induction. The micro-power source adapts the requirement of the micro electro mechanical system development for the micro-energy and comprises a substrate, a peripheral base, cantilevers and a mass block, wherein the substrate is fixed with the lower surface of the peripheral base by bonding; a vertical through hole is arranged in the middle of the mass block; an induction coil is processed on the upper surface and/or the lower surface of the mass block; a micro permanent columnar magnet is fixed on the upper surface of the substrate; PZT piezoelectric thin films are arranged on the cantilevers; a plurality of external lead bonding pads are arranged on the peripheral base; and the two ends of the induction coils and the two polarized surfaces of the PZT piezoelectric thin films are respectively connected with the corresponding external lead bonding pads by leads. The power source has reasonable and concise structure, is liable to miniaturization and integration, and can provide power to the micro electro mechanical systems at high output energy density and high output efficiency, realize self power supply of the micro electro mechanical systems and meet the requirement of the micro electro mechanical system development for the micro-energy.

An electromechanical transducer formed by an electrical and mechanical combination of a piezoelectric device and a magnetostrictive device. The two devices are electrically coupled so that their capacitive and inductive reactances approach a balance to provide an essentially resistive combined input at a selected frequency. Efficiency of circuits driving the transducer is improved. The devices are mechanically coupled so that the mechanical outputs add or reinforce each other. Two transducer pairs may be used in a two frequency telemetry system with each pair tuned to one of the frequencies for optimal reactance balancing and transduction efficiency.

Circuits (20, 220, 320, 420) are provided for applying electrical charge collected from a piezoelectric device (22) to a charge storage device (24, 224, 424). The circuits comprise a peak detector (32, 232) and a switch(es) (34, 134, 234, 434) which is/are operated to initiate transfer of the electrical charge from the piezoelectric device to the charge storage device upon detection by the peak detector (32, 232) of a peak voltage across the piezoelectric device (22). In an example embodiment, the peak detector (32, 232) comprises a peak-detection capacitance (C4); a gain element (42, 242); and a non-linear PN junction circuit (40). The circuits can also comprise charge multiplier circuit (300) configured to continue application of the electrical charge to the charge storage device (224) after the switch (262) has been turned off and/or after a point in time when magnitude of the voltage across the charge storage device (224) equals the magnitude of the voltage across the piezoelectric device (22).

In a piezoelectric actuator, a first driving signal amplified a predetermined sine wave is a applied to a piezoelectric device in a direction parallel to a polarization direction thereof. A second driving signal having a negative phase with respect to the first driving signal which is amplified the sine wave is applied to the piezoelectric device in a direction opposite to the polarization direction. Thus, the piezoelectric device is driven by a driving signal amplified the first or second driving signal double. Voltages of the first and second driving signals are much smaller than a voltage of invention of polarization of ceramic thin plates constituting the piezoelectric device.

The invention relates to the field of micro-electromechanical systems (MEMS) integrated processing and particularly relates to a piezoelectric friction combined type micro-nano generator and a prepared method thereof. A piezoelectric type generator is formed by means of using a piezoelectric film, and a friction-type generator is formed by using a piezoelectric film metal electrode and the difference between other flexible polymer materials and an electric charge binding capacity. Compared with a traditional piezoelectric type generator and a traditional friction-type generator, the piezoelectric friction combined type micro-nano generator combines the piezoelectricity with the friction and uses reasonable external circuit connection modes , so that a capacitance can be charged effectively and voltage output which reaches hectovolt can be provided. The piezoelectric friction combined type micro-nano generator and the prepared method of the piezoelectric friction combined type micro-nano generator is low in cost, high in productivity and simple in process and is provided with high voltage output and strong charging ability. The structure of the generator comprises piezoelectric film, a piezoelectric film electrode, the flexible polymer materials with micro-nano composite structure and a polymer material electrode.

A piezoelectric device is provided with a sound source IC, an amplifier for amplifying a sound source from the sound source IC, a piezoelectric speaker for generating sound based on a drive signal from amplifier, an MPU for performing a predetermined control process on the drive signal, a memory for storing temperature dependency information about the piezoelectric constant (d₁₄) and Young's modulus E of the piezoelectric speaker, and a temperature sensor for detecting an ambient temperature. MPU has correcting unit, compares a detected result of the temperature sensor with the temperature dependency information, and performs temperature correction on the drive signal serving as an acoustic signal based on a compared result. The piezoelectric speaker outputs the acoustic signal temperature-corrected by correcting unit. Thus, it becomes possible to realize various piezoelectric devices, such as a piezoelectric speaker system, capable of preventing various input information from fluctuating even when there is a change in usage environmental temperature.

A tire assembly with integrated power generation features includes one or more piezoelectric devices and power conditioning modules. Piezoelectric devices may include a plurality of piezoelectric fibers embedded in a generally unidirectional fashion within an epoxy matrix, a piezoceramic wafer provided on a substrate and substantially surrounded by a protective casing, or a piezoceramic unimorph structure adhered with a thermoplastic polyimide to respective top and bottom conductive layers. Each piezoelectric device may include multiple piezoelectric elements connected in series and/or parallel arrangements, configured with respective poling directions in opposing or in-phase arrangements and/or configured in d33 or d31 displacement modes. Piezoelectric devices are preferably mounted within a tire or wheel assembly such that electric charge is generated therein as the wheel assembly moves along a ground surface and is subsequently stored in one or more energy storage devices. Stored energy may then be used to power electronics such as a tire monitoring system that wirelessly transmits such information as tire pressure, temperature and identification variables to a remote receiver location.

A piezoelectric device includes an insulating substrate, a piezoelectric vibration device that is mounted on a device mounting pad, a metal lid member that seals the piezoelectric vibration device in an airtight manner, an external pad that is arranged outside the insulating substrate, an oscillation circuit, a temperature compensation circuit, and a temperature sensor. The lid member and the temperature sensor or the lid member and the IC component are connected to each other so as to be heat-transferable, and a heat transfer member having thermal conductivity higher than that of the material of the insulating substrate is additionally included.

In an impact type piezoelectric actuator, a driven member is movably coupled with a driving member by a friction force and the driving member is reciprocally moved by expansion and contraction of a piezoelectric device. The piezoelectric actuator is expanded and contracted by charge and discharge of electric charge thereto. A driving controller controls to vary the charging time period and the discharging time period for changing the expansion speed and the contraction speed of the piezoelectric device, so that the driven member can be moved relative to the driving member.

The modular ultrasonic clutch and brake mechanism consists of control and power source module, driving element, driven element, support assembly, pre-stress regulator, fixing seat and pedestal. Both the driving element and the driven element have piezoelectric component and contact tightly, so that the load end will rotate synchronously with the motor shaft in use as clutch and will produce braking effect in use as brake. When alternate power source is applied onto the piezoelectric components, the counter-piezoelectric effect of the piezoelectric components will make the combining surface of the mechanism produce mechanism vibration and separation, and this makes the load end stop rotating in use as clutch and the load end produce no braking effect in use as brake.

An angular rate sensor comprises a piezoelectric film having a first and a second surfaces forming an x-y plane and utilizes a perturbation mass coherently vibrating elastic acoustic waves on which a Coriolis force acts when the angular rate sensor undergoes a rotary motion about an x-direction. A first elastic acoustic wave is excited in the piezoelectric film by a driving transducer and a second elastic acoustic wave generated by the Coriolis force proportional to an angular rate of the rotary motion of the angular rate sensor itself is detected by the detecting transducer. The angular rate sensor further comprises at least a first electrode disposed on the first surface of the piezoelectric film for discharging a surface charge caused due to piezoelectric effect at the lower surface of the film in which the first elastic acoustic wave is excited.

A piezoelectric body contains a ferroelectric substance phase having characteristics such that, in cases where an applied electric field is increased from the time free from electric field application, phase transition of the ferroelectric substance phase to a ferroelectric substance phase of a different crystal system occurs at least two times. The piezoelectric body should preferably be actuated under conditions such that a minimum applied electric field Emin and a maximum applied electric field Emax satisfy Formula (1)wherein the electric field E 1 represents the electric field at which the first phase transition of the ferroelectric substance phase begins.

Discloses is apparatus and methodology for inductively coupling tire rotations related signals to a tire electronics module (200) associated with a tire. The tire electronics module (200) is configured to receive the tire rotation related signals (220) through inductive transmission from a signal transmission module (210) that includes at least a piezoelectric element (212) and a transmitter inductor (216). The signal transmitter module (210) and the tire electronics module (200) may be physically separated from each other and may be separately or collectively encased in a protective coating.

The invention provides a method of using the wind-induced vibration phenomenon of a micro structure to generate power and a micro generator based on wind-induced vibration mechanism and piezoelectric effect, wherein the micro generator comprises a silicon underlay, a composite beam/membrane comprising a piezoelectric layer and metal electrodes on the upper surface and the lower surface thereof, and the like. When the load of environmental wind causes the vibration of the composite beam/membrane structure comprising the piezoelectric layer, the vibration of the beam/membrane structure can cause the alternative change of the stress of the piezoelectric layer; due to the piezoelectric effect, the upper metal electrode and the lower electrode of the piezoelectric layer can generate an alternatively changed electric potential difference; and the electric potential difference can supply power for the load or a power accumulator. The composite beam/membrane structure comprising the piezoelectric layer can adopt a plurality of structure forms comprising a cantilever composite bema, a double-end fixedly supported composite beam, a multi-point fixedly supported composite part or a composite membrane which is partially and fixedly supported in the boundary. The micro wind turbine generator based on wind-induced vibration mechanism does not need a rotating mechanism, has a simple structure, is convenient to adopt silicon micro-processing technology to implement batch processing, has low cost, and is suitable for supplying power for wireless sensing network nodes, and the like.

A ternary single crystal relaxor piezoelectric grown from a novel melt using the Vertical Bridgeman method. The ternary single crystals are characterized by a Curie temperature, T_c, of at least 150° C. and a rhombohedral to tetragonal phase transition temperature, T_rt, of at least about 110° C. The ternary crystals further exhibit a piezoelectric coefficient, d₃₃, in the range of at least about 1200-2000 pC/N.

The invention provides a piezoelectric driven and detected miniature hemispherical resonant gyroscope and a manufacturing method thereof. The gyroscope comprises a monocrystalline silicon base, a center-fixed supporting column, a miniature hemispherical resonator, a common electrode, eight film piezoelectrics and eight uniformly-distributed signal electrodes, wherein the monocrystalline silicon base and the miniature hemispherical resonator are connected through the center-fixed supporting column; the common electrode has the same shape as that of the miniature hemispherical resonator and is located between the miniature hemispherical resonator and the piezoelectrics; the piezoelectrics have the same shapes as those of the signal electrodes and are located between the common electrode and the signal electrodes. The miniature hemispherical resonator is excited to work by adopting a piezoelectric driven manner, and a drive mode and a detection mode are matched with each other. The gyroscope is manufactured by combining an MEMS (Micro-Electromechanical Systems) bulk silicon processing process and a surface silicon processing process. According to the piezoelectric driven and detected miniature hemispherical resonant gyroscope and the manufacturing method thereof, the miniature gyroscope is driven and detected by using the inverse piezoelectric effect and the piezoelectric effect, so that the gyroscope has the characteristics of high degree of integration, low power consumption, convenience in mass production, and the like.