Murata Manufacturing Co., Ltd.

Yasuhiro Tanaka

Sasuga Kakehi

There are provided a center-electrode assembly and a manufacturing method therefor, in which electrical characteristics are stable and handling is easy, and which is suitable for mass-production, and a nonreciprocal circuit device and a communication apparatus using the center-electrode assembly. A center-electrode assembly for an isolator includes a ferrite, center-electrode patterns and insulating films deposited on the top surface of the ferrite, a ground pattern formed on the back surface of the ferrite, and connecting electrodes formed on side-faces of the ferrite. Each connecting electrode electrically connects between the center-electrode patterns formed on the top surface and the ground pattern formed on the back surface.

Center-electrode assembly and manufacturing method therefor, nonreciprocal circuit device and communication apparatus using the same

A nonreciprocal circuit device includes a laminate include a magnetic substrate composed of a ferromagnetic material, a permanent-magnet substrate laminated on the magnetic substrate, and a plurality of central conductors dispose on one of the upper surface and the lower surface of the magnetic substrate, a yoke integrated into the laminate, and a network formed within the laminate and electrically connected to any one of the plurality of central conductors.

Nonreciprocal circuit device and method of fabricating the same

A piezoelectric resonator which can be used as part of a piezoelectric component prevents self-welding of electrodes including silver provided on the surface of a piezoelectric substrate with silver coated terminals with abut with electrodes by forming high fusion point metals on the electrodes,The high fusion point metal is made by using Ni, Cr, W, Ti, Mo, Ni&mdash;Cu (monel) or their alloy. The thickness of the high fusion point metal is preferably less than about 1/10 of the thickness of the electrode,or less than 1 &mgr;m.

Piezoelectric resonator and piezoelectric components using the same

A piezoelectric resonator which can be used as part of a piezoelectric component prevents self-welding of electrodes provided on the surface of a piezoelectric and which include silver with silver coated terminals with which the electrodes abut by forming high fusion point metals on the electrodes. The high fusion point metals include Ni, Cr, W, Ti, Mo, Ni--Cu (monel) or their alloy. The thickness of the high fusion point metal is preferably less than about 1/10 of the thickness of the electrode or less than 1 .mu.m.

The invention provides an electronic part which includes a casing having a recessed portion which is free of accumulation of moisture and gases and in which a piezoelectric element and terminals are received, and a lid sealably covering the recessed portion. The casing and the lid are respectively provided with narrow grooves communicating with the recessed portion. The casing and the lid are welded together by a ultrasonic welding method at their peripheral edges with the exception of the narrow grooves and portions outside thereof, thereby forming a very narrow gap between the casing and the lid.

Electronic part comprising a casing with a narrow groove formed in the

A piezoelectric resonator includes a mother resonator element which is fixed on a bottom of a continuous storing groove which is formed in a mother base plate. An upper opening of the storing groove is covered with a mother cover plate, so that the mother base plate, the mother cover plate and the mother resonator element are simultaneously cut along a direction perpendicular to a lengthwise direction of the storing groove to form intermediate chips. Side openings of each of the intermediate chips are covered with side plates, and thereafter external electrodes are formed on outer surfaces of each of the completed chips.

Method of manufacturing piezoelectric resonator chips

A method of manufacturing a piezoelectoric resonator includes the steps of alternately layering piezoelectric device substrates and first sealing substrates to form a block-shaped layered element, and then cutting the same to provide a piezoelectric resonator element, so that a number of the resonator elements for forming piezoelectric resonators can be prepared simultaneously through laminating, adhering and cutting processes. Hence, it reduces the number of steps thereby facilitating mass-productivity and reducing the cost to produce a chip-type piezoelectric resonator.

Method of manufacturing piezoelectric resonator

There is disclosed a ladder type band-pass filter comprising plural vibrator blocks. Each vibrator block comprises a plate-shaped vibrator arranged in an electrically insulating frame. First and second metallic plates are fixed in the frame, and then, support the vibrator for vibration in the frame by arranging the vibrator between the first and second metallic plates. A pair of leading electrodes are formed on the frame so that a pair of leading electrodes are electrically connected to the first and second metallic plates, respectively, when the first and second metallic plates are fixed in the frame. Plural vibrator blocks are bonded in the axis direction of the frames, and the first and second leading electrodes of plural vibrator blocks are electrically connected so as to produce a ladder type band-pass filter.

Ladder type band-pass filter comprising of assembled plural vibrator

A laminated terminal layer is at least a double layer comprising a first layer made of a hard material and a second layer made of a soft material. The first layer is flexible. The second layer is overlapped on the first layer and in contact with an electrode of a piezoelectric ceramic resonator. Preferably, the hard material is phosphor bronze and the soft material is Al, Ag, or Pb as a simple substance or, any alloy thereof.

Laminated terminal layer for electronic component

A filter of the ladder type has an elongated hollow casing with an aperture at one axial end face and at least two grooves on the inner surface at at least two different positions around the inner periphery thereof and which extend parallel to the longitudinal axis of the body. An elongated terminal strip in the bottom of one of the grooves extends along substantially the entire length of the one groove and extends out of the casing. A plurality of piezoelectric devices and a plurality of terminal plates stacked in the casing in the direction of the longitudinal axis and in an order for forming a ladder type filter. Some of the terminal plates have terminal tips extending into the one groove in firm electrical contact with the terminal strip. The terminal tips on some of the remainder the terminal plates extend into another groove and the terminal tips some of these have longitudinally extending terminal portions extending along the groove and with which the terminal tips on some of the remainder of the terminal plates are in electric contact for forming the ladder type filter. Terminal tips on the two end terminal plates extend out of the casing.

Housing having grooves therein for mounting a piezoelectric ladder filter

A piezoelectric resonator including a piezoelectric substrate of a quadrilateral or rectangular configuration, and electrode layers provided over opposite main faces of the piezoelectric substrate for vibration of the piezoelectric substrate on the whole, and characterized in that the piezoelectric substrate is formed, in its four side edges, with notched portions having dimensions and shapes different from each other.

Piezoelectric resonator with notched sides

There are provided ladder-type piezoelectric filters, wherein each piezoelectric resonator incorporated is arranged to have opposing faces of rectangular dimensions with the ratio of a short side length to a long side length being less than a value of 0.7.

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Kanazawa, Japan

Yasuhiro Tanaka