US3521090A - Piezoelectric transducer with electrically conductive mounting rods - Google Patents

Piezoelectric transducer with electrically conductive mounting rods Download PDF

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US3521090A
US3521090A US713409A US3521090DA US3521090A US 3521090 A US3521090 A US 3521090A US 713409 A US713409 A US 713409A US 3521090D A US3521090D A US 3521090DA US 3521090 A US3521090 A US 3521090A
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transducer
stack
electrodes
electrically conductive
metal
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US713409A
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Wesley L Angeloff
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US Secretary of Navy
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B06GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06BMETHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction
    • B06B1/0607Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezo-electric effect or with electrostriction using multiple elements
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L41/00Piezo-electric devices in general; Electrostrictive devices in general; Magnetostrictive devices in general; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L41/02Details
    • H01L41/04Details of piezo-electric or electrostrictive devices
    • H01L41/047Electrodes or electrical connection arrangements
    • H01L41/0472Connection electrodes of multilayer piezo-electric or electrostrictive devices, e.g. external electrodes
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L41/00Piezo-electric devices in general; Electrostrictive devices in general; Magnetostrictive devices in general; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L41/08Piezo-electric or electrostrictive devices
    • H01L41/083Piezo-electric or electrostrictive devices having a stacked or multilayer structure
    • H01L41/0833Piezo-electric or electrostrictive devices having a stacked or multilayer structure with non-rectangular cross-section orthogonal to the stacking direction, e.g. polygonal, circular
    • H01L41/0835Annular cross-section
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L41/00Piezo-electric devices in general; Electrostrictive devices in general; Magnetostrictive devices in general; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L41/22Processes or apparatus specially adapted for the assembly, manufacture or treatment of piezo-electric or electrostrictive devices or of parts thereof
    • H01L41/27Manufacturing multilayered piezo-electric or electrostrictive devices or parts thereof, e.g. by stacking piezo-electric bodies and electrodes
    • H01L41/277Manufacturing multilayered piezo-electric or electrostrictive devices or parts thereof, e.g. by stacking piezo-electric bodies and electrodes by stacking bulk piezo-electric or electrostrictive bodies and electrodes
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L41/00Piezo-electric devices in general; Electrostrictive devices in general; Magnetostrictive devices in general; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L41/22Processes or apparatus specially adapted for the assembly, manufacture or treatment of piezo-electric or electrostrictive devices or of parts thereof
    • H01L41/29Forming electrodes, leads or terminal arrangements
    • H01L41/293Connection electrodes of multilayered piezo-electric or electrostrictive parts

Description

July 21, 1970 w. L. ANGELOFF 3,521,090

PIEZOELECTRIC TRANSDUCER WITH ELECTRICALLY CONDUCTIVE MOUNTING RODS Filed March 15, 1968 F/az Fla. 3 FIG. 4

V i s\ 1N ENTOR.

u 20 w LE) VLANGELOFF United States Patent M 3,521,090 PIEZOELECTRIC TRANSDUCER WITH ELEC- TRICALLY CONDUCTIVE MOUNTING RODS Wesley L. Angeloff, San Diego, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed Mar. 15, 1968, Ser. No. 713,409 Int. Cl. H01v 7/00 US. Cl. 3109.4 3 Claims ABSTRACT OF THE DISCLOSURE Piezoelectric discs of ceramic are metal coated on both sides, a recess in each coating being left open to the periphery of the discs. Discs are all stacked with faces of like polarity together and with corresponding disc aligned. Two grooves are cut along the side of the stack, each groove being in the center of aligned recesses to expose in each groove the edge of the metal of all coatings of one polarity. A metal rod is laid in each of the grooves and is soldered in place. The rods then constitute the electrical terminals of the tranducers.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND Certain ceramics and crystals when properly polarized have the unique property of physically distorting when subjected to an electric field. The field is usually produced within the body by electrodes of metallic paint or foil deposited on opposite faces of the body. In the interest of reduced terminal voltage and inrceased power-handling capacity, it is desirable to make the piezoelectric elements as thin waferlike bodies and to stack a large number of wafers with all electrodes of one polarity connected to a common terminal. Since the electrodes are no more substantial than either a thin foil or a metallic coating, the mechanical problem of making the electrical connections to each electrode is formidable. Where large numbers of piezoelectric bodies are employed in a single transducer, the labor of making the electrical connections to the electrodes is costly.

Accordingly, an object of this invention is to provide an improved transducer.

A more specific object of this invention is to provide a transducer which is inexpensive to manufacture and which is inexpensive to manufacture and which has reliable electrical connections to all of the electrodes.

SUMMARY After the piezoelectric wafers of the transducer of this invention have been stacked and clamped together, two parallel grooves are milled along the sides of the stack. Each groove is centered in a row of recesses provided in the electrode coatings. The edge of one electrode coating of each wafer is exposed by the milling operation so that when a rod is brazed or soldered in the goove, electrical connection is made from the rod to one of the two electrodes of each wafer.

Other objects and features of this invention will become apparent to those skilled in the art by referring to preferred embodiments described in the following specification and illustrated in the accompanying drawings in which:

FIG. 1 is an elevational view, partly in section, of one transducer constructed according to this invention,

FIG. 2 is an enlarged detailed view of a portion of one of one of the piezoelectric discs of FIG. 1,

FIGS. 3 and 4 are elevational views of opposite sides of one of the wafers of the tranducer of FIG. 1,

FIGS. 5 and 6 are side and end views of a milling cutter employed in the construction of the transducer of FIG. 1,

FIG. 7 is a detail of the electrical connection between a rod and a metal coating of the transducer of FIG. 1,

FIG. 8 shows an alternative embodiment of the wafer of this invention, and

FIG. 9 shows in exaggerated detail a cross section of the wafer, electrodes and recesses of the transducer of FIG. 1.

DESCRIPTION The transducer of FIG. 1 comprises a stack of wafers 10. It is contemplated that the wafers can be quite thin and relatively large in number. Each wafer, shown in greater detail in FIGS. 2, 3 or 4, is comprised preferably of a common piezoelectric ceramic, such as lead zirconate or lead titanate or combinations of these compounds. The central portion of the wafer is omitted to leave a flattened ring. After the ceramic is molded and partially fired to solidify the shape, a highly conductive non-corrosive metal, such as silver, is applied to each flat surface. Then, while a polarizing direct current voltage is applied between the coatings, the wafer is sintered at a high temperature to permanently fix the metal and polarize the ceramic. The electrode coatings on opposite sides of the wafers are identified throughout the drawings by the reference characters 12 and 14. In the elevation of FIG. 3, the coating 12 is shown. The coating may be applied by a spraying technique from dry or wet powdered metal, such as silver, or a metal foil cut to size may be applied adhesively to the ceramic. A recessed area 12a is provided in the edge of a metal, the recess being open to the periphery of the wafer.

In the elevation of FIG. 4, the metal electrode 14 on the other side of the wafer is shown. The recess 14a is provided at the edge of the electrode, open to the periphery of the wafer such as degrees shown in FIGS. 3 and 4 or say 45 degrees shown in FIG. 8.

Next the wafers are stacked, care being taken to place face-to-face electrodes of like polarity. For this purpose, the electrical polarity of the faces of the wafers are identified by some indexing mark. Further, recess of coatings of one polarity must be aligned along the side of the stack. It is preferred that the stack be consolidated by the adhesive 20, FIG. 9, between the wafers. The adhesive can be electrically conductive or not. Preferably, each face is wetted, and stacked and then fairly high pressure applied to expel most of the adhesive. The pressure should be sufficient to reduce joint thickness to less than .001 inch, preferably.

Upon curing the cement or while in clamps, the assembly is ready for the unique step, according to this invention, of exposing the metal edges of each electrode for electrical connection. According to an important feature of this invention this step is performed by cutting grooves 22 along the side of the stack. The milling cutter 18 of suflicient hardness to cleanly cut the ceramic is shown in FIGS. 5 and 6. One cut is made along the center of the aligned recesses 12a and another cut is made along the center of the aligned recesses 14a. Each cut exposes all electrodes of like polarity and leaves the electrodes of opposite polarity safely removed from the bottom of the cut. That is, the recess 12a and 14a from the periphery of the discs is considerably more than the depth of the cuts 22.

Finally a coat 24 of solder or brazing metal in wet or dry form is applied liberally to the interior of the grooves and/or the rods 26 where it will flow into contact with the cut edges 28. The metal rods 26 are carefully selected as to diameter and are laid in the grooves. Upon firing to the melting temperature of the solder, the rod is found to firmly bond to the ceramic and to permanent connect electrically to the newly cut edges of the electrodes 12 or 14.

Alternatively, the notches comprising the grooves 22 may be separately formed in each disc before assembly in the stack. Then, when the coatings 12 and 14 are applied, the recesses 12a and 14a are carefully centered over the notches to prevent short circuits between electrodes.

Conveniently, the rods 26 may be extended beyond the ends of the stack to provide terminals for the positive and negative terminals of the signal source. The finished transducer is particularly rugged and rough handling will not break the electrical connection to any of the fragile electrode foils or coatings. Because the wafers can be made very thin, the capacitance between the terminals can be made quite high and the voltage of the source can be materially lowered even at a high energy level. While silver paint has been used other non-corrosive metals may be employed.

A test stack made using silver foil .0004 inch thick and glue joints .0006 inch thick, and Wafers only 0.1 inch thick, operated well with an 80O volt signal source.

I claim:

1. A piezoelectric transducer comprising:

a stack of polarized piezoelectric discs, each disc being relatively thin and flat and of uniform predetermined outside size and shape,

a thin metal electrode in good over-all contact with each face of each of said discs,

a recess in each electrode open to the periphery of the associated disc, the discs in said stack being oriented 4 to align the recesses of one polarity along the side of said stack,

a cut groove along the side of said stack in the edges of said discs, said groove being cut centrally in the aligned recesses and being of a depth less than the depth of said recesses so as to expose in said groove the edge of one electrode of each disc, and

a metal rod soldered in each groove to make electrical contact with the cut edges of all electrodes of said one polarity.

2. In the transducer defined in claim 1,

the mentioned recesses in said electrodes of each disc being spaced a predetermined distance apart along the disc periphery.

3. In the transducer defined in claim 1,

electrodes of like polarity being placed face-to-facein said stack.

References Cited UNITED STATES PATENTS 2,636,134 4/1953 Arons et al. 3109.8 X 2,771,663 11/ 1956 Henry.

3,075,098 1/ 1963 Shoot 310--9.1 X 3,179,826 4/1965 Trott et al. 3109.7 X 3,281,612 10/1966 Hatschek 310-9.8 3,378,704 4/1968 Miller et al. 3109.7 X 3,390,287 6/1968 Sonderegger 3l0-9.7 X

WARREN E. RAY, Primary Examiner M. O. BUDD, Assistant Examiner US. Cl. X.R. SIG-9.6, 9.8

US713409A 1968-03-15 1968-03-15 Piezoelectric transducer with electrically conductive mounting rods Expired - Lifetime US3521090A (en)

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831043A (en) * 1971-12-28 1974-08-20 Siemens Ag Piezoelectric oscillator arrangements
JPS5166756U (en) * 1974-11-21 1976-05-26
US4415826A (en) * 1981-07-16 1983-11-15 Siemens Aktiengesellschaft Support and connection device for a disc-shaped piezoelectric resonator
US4471256A (en) * 1982-06-14 1984-09-11 Nippon Soken, Inc. Piezoelectric actuator, and valve apparatus having actuator
US4523121A (en) * 1982-05-11 1985-06-11 Nec Corporation Multilayer electrostrictive element which withstands repeated application of pulses
US4667127A (en) * 1983-12-28 1987-05-19 Avl Gesellschaft Fur Verbrennungskraftmaschinen Und Messtechnik Mbh, Prof. Dr.Dr.H.C. Hans List Piezoelectric sensor element with at least two single crystal elements
US4805157A (en) * 1983-12-02 1989-02-14 Raytheon Company Multi-layered polymer hydrophone array
US5438232A (en) * 1991-01-25 1995-08-01 Murata Manufacturing Co., Ltd. Piezoelectric lamination actuator
US5493165A (en) * 1993-10-14 1996-02-20 At&T Corp. Force generator for electrostrictive actuators
US6940213B1 (en) * 1999-03-04 2005-09-06 Robert Bosch Gmbh Piezoelectric actuator
US20090168603A1 (en) * 2007-12-26 2009-07-02 Denso Corporation Ultrasonic sensor
US20090260422A1 (en) * 2008-04-18 2009-10-22 Denso Corporation Ultrasonic sensor
US20100156250A1 (en) * 2004-03-09 2010-06-24 Kyocera Corporation Multi-Layer Piezoelectric Element and Method for Manufacturing the Same
DE102009040264A1 (en) * 2009-09-04 2011-03-10 Volkswagen Ag Ultrasonic waves producing method for e.g. aircraft, involves causing thickness mode of vibrations between converter and component during activation of converter, and producing ultrasonic waves by thickness mode of vibrations
DE10256980B4 (en) * 2001-12-06 2011-11-10 Denso Corporation Manufacturing method for a stacked ceramic body
DE102008064736B3 (en) * 2007-12-26 2013-11-07 Denso Corporation Ultrasonic sensor for use as obstacle sensor in e.g. vehicle, has synchronous detection device performing synchronous detection of received signal of non-reference receiver devices on basis of reference signals

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636134A (en) * 1947-10-01 1953-04-21 Arnold B Arons Piezoelectric pressure gauge element
US2771663A (en) * 1952-12-04 1956-11-27 Jr Robert L Henry Method of making modular electronic assemblies
US3075098A (en) * 1957-12-26 1963-01-22 Endevco Corp Accelerometer
US3179826A (en) * 1961-09-14 1965-04-20 Trott Winfield James Piezolelectric assembly
US3281612A (en) * 1962-09-12 1966-10-25 List Hans Piezoelectric device, particularly a force measuring instrument and the process of manufacturing same
US3378704A (en) * 1966-01-05 1968-04-16 Bourns Inc Piezoelectric multilayer device
US3390287A (en) * 1964-12-10 1968-06-25 Kistler Instrumente Ag Piezo-electric building units

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636134A (en) * 1947-10-01 1953-04-21 Arnold B Arons Piezoelectric pressure gauge element
US2771663A (en) * 1952-12-04 1956-11-27 Jr Robert L Henry Method of making modular electronic assemblies
US3075098A (en) * 1957-12-26 1963-01-22 Endevco Corp Accelerometer
US3179826A (en) * 1961-09-14 1965-04-20 Trott Winfield James Piezolelectric assembly
US3281612A (en) * 1962-09-12 1966-10-25 List Hans Piezoelectric device, particularly a force measuring instrument and the process of manufacturing same
US3390287A (en) * 1964-12-10 1968-06-25 Kistler Instrumente Ag Piezo-electric building units
US3378704A (en) * 1966-01-05 1968-04-16 Bourns Inc Piezoelectric multilayer device

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831043A (en) * 1971-12-28 1974-08-20 Siemens Ag Piezoelectric oscillator arrangements
JPS5166756U (en) * 1974-11-21 1976-05-26
US4415826A (en) * 1981-07-16 1983-11-15 Siemens Aktiengesellschaft Support and connection device for a disc-shaped piezoelectric resonator
US4523121A (en) * 1982-05-11 1985-06-11 Nec Corporation Multilayer electrostrictive element which withstands repeated application of pulses
US4471256A (en) * 1982-06-14 1984-09-11 Nippon Soken, Inc. Piezoelectric actuator, and valve apparatus having actuator
US4805157A (en) * 1983-12-02 1989-02-14 Raytheon Company Multi-layered polymer hydrophone array
US4667127A (en) * 1983-12-28 1987-05-19 Avl Gesellschaft Fur Verbrennungskraftmaschinen Und Messtechnik Mbh, Prof. Dr.Dr.H.C. Hans List Piezoelectric sensor element with at least two single crystal elements
US5438232A (en) * 1991-01-25 1995-08-01 Murata Manufacturing Co., Ltd. Piezoelectric lamination actuator
US5493165A (en) * 1993-10-14 1996-02-20 At&T Corp. Force generator for electrostrictive actuators
US6940213B1 (en) * 1999-03-04 2005-09-06 Robert Bosch Gmbh Piezoelectric actuator
DE10256980B4 (en) * 2001-12-06 2011-11-10 Denso Corporation Manufacturing method for a stacked ceramic body
CN101694865B (en) * 2004-03-09 2013-03-20 京瓷株式会社 Multilayer piezoelectric element and its manufacturing method
US8125124B2 (en) * 2004-03-09 2012-02-28 Kyocera Corporation Multi-layer piezoelectric element and method for manufacturing the same
US20100156250A1 (en) * 2004-03-09 2010-06-24 Kyocera Corporation Multi-Layer Piezoelectric Element and Method for Manufacturing the Same
DE102008054533B4 (en) * 2007-12-26 2012-11-08 Denso Corporation Ultrasonic sensor
US8009518B2 (en) 2007-12-26 2011-08-30 Denso Corporation Ultrasonic sensor with piezoelectric elements and vibration isolator
DE102008064736B3 (en) * 2007-12-26 2013-11-07 Denso Corporation Ultrasonic sensor for use as obstacle sensor in e.g. vehicle, has synchronous detection device performing synchronous detection of received signal of non-reference receiver devices on basis of reference signals
DE102008064735B3 (en) * 2007-12-26 2013-11-28 Denso Corporation Ultrasonic sensor
US8164982B2 (en) 2007-12-26 2012-04-24 Denso Corporation Ultrasonic sensor with piezoelectric elements and acoustic matching members
US20090168603A1 (en) * 2007-12-26 2009-07-02 Denso Corporation Ultrasonic sensor
DE102008054533B8 (en) * 2007-12-26 2013-02-14 Denso Corporation Ultrasonic sensor
US8616061B2 (en) 2008-04-18 2013-12-31 Denso Corporation Ultrasonic sensor
DE102009061087B3 (en) * 2008-04-18 2012-06-14 Denso Corporation Ultrasonic sensor
US8166824B2 (en) 2008-04-18 2012-05-01 Denso Corporation Ultrasonic sensor
DE102009017507B4 (en) * 2008-04-18 2011-12-08 Denso Corporation Ultrasonic sensor
US20090260422A1 (en) * 2008-04-18 2009-10-22 Denso Corporation Ultrasonic sensor
DE102009040264A1 (en) * 2009-09-04 2011-03-10 Volkswagen Ag Ultrasonic waves producing method for e.g. aircraft, involves causing thickness mode of vibrations between converter and component during activation of converter, and producing ultrasonic waves by thickness mode of vibrations

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