Murata Manufacturing Co., Ltd.

New Japan Radio Co., Ltd.

Toshio Imanishi

Toshiaki Kaji

Hitoshi Matsuno

Keiichi Umeda

Ville Kaajakari

Masakazu Yamauchi

Yoshihiro Sonoda

Takahiro Matto

Yasuyuki Endou

A self-oscillating piezoelectric actuator drive circuit includes a integrating circuit; an inverter (INV), inverters (INVand INV) inverting an output signal of the inverter (INV), sense resistors (Rsand Rs) connected to output sides of the inverters (INVand INV), a positive feedback resistor (Rfb) feeding back an output signal of the inverters (INVand INV) to the integrating circuit; and a negative feedback resistor (Rfb) feeding back a voltage generated from the sense resistors (Rsand Rs, Rs&#x3c;Rsin terms of a resistance value) to the integrating circuit. In a startup state, the sense resistor (Rs) and the inverter (INV) are selected, and in an operating state after the startup state, the sense resistor (Rs) and the inverter (INV) are selected.

Piezoelectric actuator drive circuit

An oscillation circuits that provides stable oscillations even when the amount of phase rotation of a piezoelectric resonator is small or fluctuates. The oscillation circuit includes a first amplifier having an input and an output, and a piezoelectric resonator connected between the input and the output of the first amplifier. Moreover, the oscillation circuit feeds, back to the input, a current flowing from the output of the first amplifier to the piezoelectric resonator. The oscillation circuit further includes an alternating-voltage waveform shaping circuit that applies, to the piezoelectric resonator, an alternating-voltage waveform having rising portions sharper than those of a sine wave.

Oscillation circuit and oscillation-circuit driving method

A piezoelectric device that includes: a diaphragm; a supporting part configured to support at least a portion of an end of the diaphragm; a piezoelectric film disposed along a portion supported by the supporting part on the diaphragm, a width of the film along the supported portion being narrower than a width of the portion; a lower electrode disposed at a face of the piezoelectric film on a diaphragm side; and an upper electrode disposed on a face of the piezoelectric film on an opposite side to the diaphragm.

Piezoelectric device

A piezoelectric sound component that includes a resin sheet, a piezoelectric diaphragm, and a casing. The piezoelectric diaphragm vibrates by bending, and is attached to at least part of a central portion of the resin sheet excluding a peripheral portion of the resin sheet. The casing holds the peripheral portion of the resin sheet. The casing supports at least one corner portion of the piezoelectric diaphragm.

Piezoelectric sound component

A sound production component that includes a vibration element, a support member, and a connection part. The vibration element includes a polygonal vibration plate and an electromechanical conversion element attached to the vibration plate. The connection part connects an entire periphery of the vibration plate to the support member. At least a portion of the connection part has a curved shape. The length of a portion of the connection part which connects each corner of the vibration plate and the support member is shorter than the length of a portion of the connection part which connects a central portion of each side edge of the vibration plate and the support member.

Sound production component

A monolithic piezoelectric transformer includes a drive portion and a power generation portion. The drive portion includes a plurality of polarized piezoelectric ceramic layers and a plurality of internal electrodes that are alternately layered on each other. The drive portion is provided with external input electrodes connected to the internal electrodes. The power generation portion includes a piezoelectric ceramic member and an output electrode. The internal electrodes are formed of a fired metal containing at least one of silver and palladium and at least one of rhodium and iridium.

Monolithic piezoelectric transformer and method for manufacturing the same

A method for making a monolithic piezoelectric ceramic element having high mechanical strength, excellent piezoelectricity, and high reliability is disclosed. The method includes the steps of applying a conductive paste including a conductor containing Ag as a principal ingredient to ceramic green sheets comprising a piezoelectric ceramic material containing a Pb compound, stacking the ceramic green sheets to form a laminate, and firing the laminate in an atmosphere with an oxygen concentration of about 90% by volume or more during the heating period and with an oxygen concentration of about 5% to 15% by volume during the isothermal period and during the cooling period.

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Nagaokakyo, Japan

Toshio Imanishi