Murata Manufacturing Co., Ltd.

Kunio Sawai

Yoshihiro Ikeda

Motohide Yonemura

Syuji Fujii

Tomoaki Futakuchi

Taketoshi Hino

Hisayuki Hashimoto

An FM detector circuit includes a bridge circuit having four sections with a discriminator connected as one of the four sections. An FM intermediate frequency is applied across one pair of diagonally opposed nodes of the bridge circuit and an output is picked up across the other pair of diagonally opposed nodes of the bridge circuit. The discriminator includes a piezoelectric material that is selected to produce stable overall temperature characteristics.

FM detector circuit

Piezoelectric resonator and FM detection circuit incorporating the same

A method for manufacturing a piezoelectric device includes the steps of providing a piezoelectric substrate having a piezoelectric driving unit and laminating outer coating substrates on major surfaces thereof via adhesive layers. Each of the adhesive layers includes a first layer of an adhesive having a Shore D hardness after curing of not more than approximately 60 and disposed so as not to be exposed in a region of lateral side surfaces of the layered body provided with the external electrodes, second and third layers of an adhesive having a Shore D hardness of at least approximately 60, and the third layer of having a viscosity before curing of at least approximately 3.0&times;10 mPas at a temperature of 25&deg; C. The third layer is disposed between the periphery of the first layer and the region of the lateral side surfaces of the layered body provided with the external electrodes.

Method for manufacturing a piezoelectric device

A low-cost piezoelectric component which is efficiently manufactured and which provides excellent electrical characteristics, includes a piezoelectric element, a damping member, a supporting substrate for mounting the piezoelectric element, and a cover member. On a surface of the piezoelectric element, the damping member has a predetermined hardness and a vibrating electrode. In the case of a piezoelectric trap filter, a damping member is provided which has a Shore hardness of about 35 to about 80. In the case of a piezoelectric discriminator, the damping member has a Shore hardness of about 80 to about 100.

Piezoelectric component

A piezoelectric device includes a piezoelectric substrate having a piezoelectric driving unit and provided with outer coating substrates laminated on major surfaces thereof via adhesive layers, and external electrodes provided on the outer surfaces of a layered body included in the piezoelectric device. In the piezoelectric device, each of the adhesive layers includes a first layer of an adhesive having a Shore D hardness after curing of not more than approximately 60, and disposed so as not to be exposed in a region of lateral side surfaces of the layered body provided with the external electrodes, a second layer of an adhesive having a Shore D hardness of at least approximately 60, and a third layer of an adhesive having a Shore D hardness of at least approximately 60 and having a viscosity before curing of at least approximately 3.0&times;10,mPas at a temperature of 25&deg; C. The third layer is disposed between the periphery of the first layer and the region of the lateral side surfaces of the layered body provided with the external electrodes.

Piezoelectric device and method for manufacturing the same

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.

Growing community of inventors

Ishikawa-ken, Japan

Kunio Sawai