Murata Manufacturing Co., Ltd.

Shungo Kanai

Gaku Kamitani

Atsuhiko Hirata

Masao Gamo

Yoko Kaneda

Hiroaki Kaida

Hitoshi Sakaguchi

Hiroaki Wada

Hiroyuki Ukai

Hiroyuki Hayashi

Midori Sunaga

A piezoelectric element, which is capable of being driven with a relatively low voltage and obtaining a large displacement amount at a central portion thereof and is not degraded in characteristics over time and is easily mountable on or in a piezoelectric device, includes a piezoelectric body including a plurality of laminated piezoelectric layers, ground electrodes, central electrodes, and peripheral electrodes. A surface of the piezoelectric body includes first to fifth terminals. The extraction of the ground terminals, the central electrodes, and the peripheral electrodes to the first to fifth terminals is configured to connect one terminal of an alternating-current power supply to the third terminal and connect the other terminal of the alternating-current power supply to the first terminal and the second terminal.

Piezoelectric element and piezoelectric device using the same

In a piezoelectric micro-blower, a vibration plate assembly includes a piezoelectric element attached to a diaphragm, with an intermediate plate interposed there between. A blower chamber plate includes a circular opening in a center thereof. A blower chamber defined by the diaphragm, a flow path plate, and the opening of the blower chamber plate is sized to allow internal pressure to be substantially uniformly changed by vibration of the diaphragm. The blower chamber plate and the flow path plate are provided with a first outlet and a second outlet, respectively. Compressive fluid pressurized in the blower chamber is blown out through the first and second outlets.

Piezoelectric micro-blower

A piezoelectric microblower includes a vibrating plate including a piezoelectric element and arranged to be driven in a bending mode by applying a voltage of a predetermined frequency to the piezoelectric element, and a blower body arranged to fix both ends or a periphery of the vibrating plate and to define a blower chamber between the blower body and the vibrating plate, an opening being provided in a portion of the blower body facing a central portion of the vibrating plate. In a portion of the blower chamber corresponding to the central portion of the vibrating plate, a partition is provided around the opening and a resonance space is defined inside of the partition. A size of the resonance space is set such that a driving frequency of the vibrating plate and a Helmholtz resonance frequency of the resonance space correspond to each other.

Piezoelectric microblower

A piezoelectric micro-blower capable of efficiently conveying compressive fluid without use of a check valve and ensuring a sufficient flow rate. The micro-blower has a blower body with a first wall and a second wall. Openings are formed in the respective walls and face a center of a diaphragm. An inflow path allowing the openings to communicate with the outside is formed between the walls. By applying a voltage to a piezoelectric element to cause the diaphragm to vibrate, a part of the first wall close to the first opening vibrates. Thus, gas can be drawn from the inflow path and discharged from the opening in the second wall.

A piezoelectric pump includes a diaphragm that defines a pump chamber between the diaphragm and a pump body, and a piezoelectric element bonded to a surface of the diaphragm. The piezoelectric element is a bimorph piezoelectric element in which a plurality of piezoelectric layers are stacked, including a neutral layer disposed in the approximate middle of the piezoelectric element in the thickness direction and that is not displaced. The piezoelectric element can be efficiently displaced because a neutral plane of the diaphragm and the piezoelectric element bonded therein is located in the neutral layer.

Piezoelectric pump

A piezoelectric pump includes a pump body with a pump chamber, and a piezoelectric element that closes the pump chamber. The central area and the peripheral area of the piezoelectric element are bent in opposite directions by applying voltages to the piezoelectric element so that the volume of the pump chamber is changed. The piezoelectric element is a laminate including a plurality of piezoelectric layers with electrodes interposed therebetween. The central area and the peripheral area of each piezoelectric layer are polarized opposite to each other in the thickness direction, and the electrodes are formed such that voltages in the same direction in the thickness direction are applied to the central area and the peripheral area of each piezoelectric layer. Since voltages at the same potential are applied to the electrodes formed in the same planes of the piezoelectric layers, short-circuits caused by migration can be prevented.

An energy-trapping strip piezoelectric vibrator utilizing a third harmonic overtone of a thickness shear mode is provided. A piezoelectric vibratorhas a strip piezoelectric ceramic substratepolarized in a longitudinal direction, and first and second excitation electrodesandprovided on first and second principal surfacesandof the piezoelectric ceramic substrate. An excitation regionincluding a piezoelectric vibration portion that includes a portion where the first and second excitation electrodesandoverlap and that utilizes harmonics of the thickness shear mode is formed. A region around the piezoelectric vibration portion is set as a non-excitation region. At least a region of the non-excitation region neighboring the piezoelectric vibration portion is a region having the same polarization axis direction as the excitation regionand a relatively small polarization degree or is an unpolarized region.

Piezoelectric vibrator

A laminated piezoelectric component or filter is arranged such that a change in the resonance frequency before and after a high temperature heat treatment such as reflowing is minimized and the distribution of the resonance frequency is also minimized. The laminated filter includes a piezoelectric substrate having a vibrating electrode provided on the back surface of the substrate, cover substrates, and adhesives located between the piezoelectric substrate and cover substrate. The change in the center frequency Fo due to the heat applied to the piezoelectric substrate during reflowing is canceled by the change of the center frequency Fo caused by the synthesized stress imparted to the piezoelectric substrates from the cover substrates and adhesives.

Laminated piezoelectric component

First resonant electrodes are provided on one main surface of a piezoelectric plate, a second resonant electrode is provided on the other main surface of the piezoelectric plate, such that the first and second resonant electrodes face each other. An energy trap-type piezoelectric vibrating section is thus provided by the first and second resonant electrodes, and a capacitor section is provided in a position separated from the vibrating section. The capacitor section has a first capacitor electrode provided on the upper surface of the piezoelectric plate, and has a second capacitor electrode provided on the bottom surface of the piezoelectric plate. Further, an outer edge portion of the first capacitor electrode is spaced from an outside edge of the piezoelectric plate, thus providing a margin area except at the portions led out to the outside edge of the piezoelectric plate.

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Nagaokakyo, Japan

Shungo Kanai