Murata Manufacturing Co., Ltd.

Seigo Hayashi

Michio Kadota

Hideya Horiuchi

Junya Ago

Masanaga Nishikawa

Yasunori Takakuwa

Akira Ando

Toshihiko Kittaka

Mamoru Ikeura

Haruo Morii

Kazuo Shima

Chikashi Kondo

Shinji Amaike

An ultrasonic sensor includes a cylindrical casing having a bottom portion. The casing has a piezoelectric element on a bottom surface thereof. A substrate is attached to an end surface of an opening portion of the casing with a damping member provided therebetween such that the damping member covers the opening portion. Pin terminals are arranged so as to extend through the substrate and the damping member and are electrically connected to the piezoelectric element with lead wires. An inner space of the casing is filled with foamable resin.

Ultrasonic sensor and method for manufacturing the same

An ultrasonic sensor includes a cylindrical case with a bottom. A piezoelectric element is bonded to an inner side of a bottom portion of the case, and a felt is bonded to the piezoelectric element. A cap is fitted to an opening of the case. The cap includes a fixing portion and a substrate which is harder than the fixing portion. Terminals are press-fitted to the substrate. Wires are connected to the terminals, so that the terminals are electrically connected to the piezoelectric element. A through hole is provided in the fixing portion. Resin before being foamed is injected from the through hole and then foamed, so that the case is filled with foamable resin while an excess amount of foamable resin is pushed out from the through hole.

Ultrasonic sensor

A method for adjusting a frequency characteristic of an edge reflection type surface acoustic wave device includes the step of obtaining a frequency characteristic of an edge reflection type surface acoustic wave device having a piezoelectric substrate. The edge reflection type surface acoustic wave device has a pair of edges of the piezoelectric substrate which define a predetermined distance therebetween. The piezoelectric substrate is cut at a position which defines a distance that is shorter than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be higher than the obtained frequency characteristic. The piezoelectric substrate is cut at a position which defines a distance that is longer than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be lower than the obtained frequency characteristic.

Method for producing an edge reflection type surface acoustic wave device

A method of manufacturing an edge reflection type surface acoustic wave device includes the step of preparing a surface acoustic wave mother substrate having a plurality of interdigital transducers formed on one main surface thereof. A cut groove is formed in the substrate by cutting the surface acoustic wave mother substrate beginning from the one main surface side thereof. This step of forming a cut groove is repeated so as to produce a plurality of cut grooves so that the first reflection edge of the respective surface acoustic wave devices are sequentially formed. Next, similarly, cut grooves are sequentially formed on the surface acoustic wave mother substrate from the one main-face side thereof so as not to reach the other main surface thereof, whereby the second reflection edges of the respective surface acoustic wave devices are sequentially formed.

Method of producing edge reflection type surface acoustic wave device

A surface acoustic wave filter includes a glass substrate, an interdigital transducer provided on the glass substrate, a piezoelectric film arranged on the glass substrate so as to cover the interdigital transducer; a terminal electrode provided on the glass substrate and electrically connected to the interdigital transducer; and a coating film having an area smaller than that of the terminal electrode. The coating film is arranged on the terminal electrode such that a portion of a top surface of the terminal electrode is exposed throughout the periphery thereof.

Surface acoustic wave filter with terminal electrode coating film

A method of driving a piezoelectric bimorph device in which first and second piezoelectric ceramic layers are so electrically connected to each other as to expand or contract in the opposite directions, which is characterized in that when t.sub.1 is taken as the thickness of one of the first and second piezoelectric ceramic layers, Ec is taken as the coercive field strength of a piezoelectric material constituting the piezoelectric ceramic layer, and V.sub.1 is taken as the minimum value of the produce Ec.times.t.sub.1 =Vc.sub.1, and t.sub.2 is taken as the thickness of the other piezoelectric ceramic layer, Ec is taken as the coercive field strength Ec of a piezoelectric material constituting the piezoelectric ceramic layer, and V.sub.2 is taken as the minimum value of the produce Ec.times.t.sub.2 =Vc.sub.2, a voltage of not less than (V.sub.1 +V.sub.2) is applied to said piezoelectric bimorph device.

Growing community of inventors

Komatsu, Japan

Seigo Hayashi