Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Taketoshi Hino

Tomoaki Futakuchi

Kazuyuki Noto

Kunio Sawai

Jiro Miyazaki

Daisaku Kugou

Yoshikatsu Maeda

A piezoelectric vibration device is constructed to suppress interference between resonance sections and achieve a satisfactory resonance characteristic and sufficient mechanical strength. In the piezoelectric vibration device, a plurality of resonance sections are provided on a piezoelectric substrate and a slit is provided so as to extend from one side of the piezoelectric substrate toward a center thereof in order to suppress interference between the resonance sections. If the length of the slit is denoted as a, the gap width along the opposing direction of the first and second resonance electrodes in the resonance section as g, the distance from the center of the gap to the nearest side of the piezoelectric substrate and the sides of the slit as L.sub.1, and the external dimension of the piezoelectric substrate along one direction as L, then the expression L.sub.1 -g/2=b, b&lt;a.ltoreq.(3/4)L is satisfied.

Piezoelectric vibration device

A piezoelectric filter has a significantly reduced size and a sufficient coupling capacitance while avoiding an uneven outer configuration of an overall shape of the filter. The piezoelectric filter includes a first resonating unit and a second resonating unit and a coupling capacitance unit disposed in a piezoelectric substrate. The coupling capacitance unit is provided with a first coupling capacitance electrode located on an upper surface of the piezoelectric substrate and a second coupling capacitance electrode located on a lower surface thereof and the first and second coupling capacitance electrodes are arranged to extend to side edge surfaces of the piezoelectric substrate.

Piezoelectric filter having a capacitance electrode extending onto a

A piezoelectric device which has a piezoelectric substrate and a plurality of piezoelectric resonators provided on the substrate. The piezoelectric resonators are an energy-confining type, and when a voltage is impressed on the piezoelectric resonators, each of the piezoelectric resonators generates a primary vibration in a direction of the thickness of the substrate and a secondary vibration in a direction on the surface of the substrate. The secondary vibration, in the form of an oscillatory wave, is propagated on the surface of the substrate and is attenuated gradually. At least two of the piezoelectric resonators have propagation paths of secondary vibrations which are substantially parallel to each other so as not to intersect within the substrate.

Piezoelectric device including substantially parallel propagation paths

A piezoresonator which has, on a piezoelectric substrate, a plurality of oscillation sections and a coupling capacitor section for electrically connecting the oscillation sections with each other. The piezoelectric substrate is polarized, while the portion holding the coupling capacitor section is partly left unpolarized. Alternatively, the piezoelectric substrate is entirely polarized such that the portion holding the coupling capacitor section has a lower intensity of polarization than the rest of the substrate. The polarization is carried out, for example, in the following process: first, a direct voltage is applied to the entire piezoelectric substrate so as to polarize the substrate entirely with a high intensity; and then, a direct voltage with the inverse polarity of the former direct current is applied only to the portion holding the coupling capacitor section so as to lower the intensity of polarization of the portion.

Piezoresonator with a built-in capacitor and a manufacturing method

In a chip-type piezoelectric-resonator, which is protected with thermosetting resin, mother sheets are bonded to cover both major surfaces of a mother substrate having a plurality of piezoelectric resonance elements which are provided on a piezoelectric substrate, in order to properly form vibrating spaces. The mother sheets are provided with concave portions for defining cavities for vibration. Then, protective resin is applied to cover the mother substrate which is bonded with the mother sheets, and thereafter the mother substrate is divided so as to obtain a plurality of chip-type piezoelectric-resonators.

Growing community of inventors

Toyama, Japan

Taketoshi Hino