US3071841A - Method of longitudinally pre-polarizing bodies consisting of at least one layer of piezoelectric material - Google Patents

Method of longitudinally pre-polarizing bodies consisting of at least one layer of piezoelectric material Download PDF

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US3071841A
US3071841A US715044A US71504458A US3071841A US 3071841 A US3071841 A US 3071841A US 715044 A US715044 A US 715044A US 71504458 A US71504458 A US 71504458A US 3071841 A US3071841 A US 3071841A
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electrodes
polarizing
polarization
layer
piezoelectric material
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US715044A
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Brussaard Jan Maarten
Hekkert Jan Willem
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G7/00—Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture
    • H01G7/02—Electrets, i.e. having a permanently-polarised dielectric
    • H01G7/025—Electrets, i.e. having a permanently-polarised dielectric having an inorganic dielectric
    • H01G7/026—Electrets, i.e. having a permanently-polarised dielectric having an inorganic dielectric with ceramic dielectric
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/04—Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning
    • H10N30/045—Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning by polarising
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/42—Piezoelectric device making

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  • the present invention relates to a method for the longitudinal pre-polarization of bodies consisting of at least one layer of homogeneous, polycrystalline, ceramic, piezoelectric material having remanent polarization properties, which pre-polarization occurs in a medium having a high breakdown-strength, the main faces of the layers being provided with a number of parallel electrodes located at right angles or substantially at right angles to the sense of polarization, while the polarization between adjacent pairs of electrodes is of opposite sense.
  • Longitudinal pre-polarization means that the remanent polarization extends substantially in the direction of the longitudinal axis of the body.
  • the electrodes should theoretically be provided inside the material at right angles to the main surfaces of the body, but this is difficult to realize in practice.
  • the polarization also has a transverse component, but the distance measured in the longitudinal direction between the electrodes to which the polarization is applied wholly or in part may be chosen to be so large with respect to the thickness of the body that the influence of the transverse component of the remanent polarization is, in practice, negligible.
  • the said distance in the longitudinal direction of the body measured between the electrodes of opposite polarity is preferably twice as large as the thickness of the body.
  • the method according to the invention in which this disadvantage occurs to a much lesserdegree, consists in that one polarity of the polarization voltage is applied to the electrodes resting on one main face, and the other polarity is applied to the electrodes resting on the other mainface between each two adjacent electrodes on the first-mentioned main face.
  • advantage is taken from the fact that, as a result of said placement of the electrodes the whole bundle of lines of force passes through the material.
  • a further advantage of the method according to the invention over that according to said U.S.A. patent specification is, that for obtaining the same capacity, half the electrode surface is sufiicient, while obtaining the same output voltage.
  • the invention is particularly advantageous when carry ing out this method in pre-polarizing large numbers of such bodies simultaneously.
  • the bodies are pre-polarized in a bath containing oil as a medium having a high breakdown-strength, a breakdown then rendering the bath unsuitable for a next polarization, so that large-scale production is not feasible.
  • this disadvantage occurs to a much lesser degree in large-scale pro-polarization, since, as mentioned above, the risk of arcing-over per se has already been reduced. In so far as arcing-over is still to be feared 3,071,841 Patented Jan.
  • FIG. 1 shows a member pre-polarized according to a known method
  • FIG. 2 shows a member pre-polarized with the aid of the method according to the invention.
  • the reference numeral 1 designates a body of ceramic, piezo-electric material, for example BaTiO the main faces of which are provided with electrodes 2, 3, 4, 5, 6 and 7.
  • the electrodes 2, 3 and the electrodes 3, 4 on the upper main face each constitute a pair of electrodes, similarly the electrodes 5, 6 and 6, 7 respectively each constitute a pair of electrodes on the lower main face.
  • the pre-polarization is effected so as to be of opposite sense between adjacent pairs of electrodes (2, 3 and 3, 4).
  • the bundle of lines of forces passes in part along the surface beyond the material, as represented schematically in FIG. 1. This often gives rise to arcing-over along the surface of the body.
  • FIG. 2 shows a body of ceramic, piezo-electric material the main faces of which are provided with electrodes 9, 10 and 11.
  • the method according to the invention consists in that one polarity of the polarization voltage is applied to electrodes 9, 10 resting on the upper main face, while the other polarity is applied to the electrode 11 on the lower main face between the two upper adjacent electrodes on the upper main face.
  • the electrodes 9, 11 on the one hand and the electrodes 10, 11 on the other hand constitute a pair of electrodes.
  • the whole bundle of lines of force passes through the material.
  • the electrodes 9, 10, 11 may be applied to the ceramic body by the nonal techniques, such as described in the U.S.A. Patent 2,540,187 with respect to the electrodes 2, 3, 4, 5, 6, 7.
  • a method of polarizing a ceramic, piezoelectric body comprising disposing on a first surface of the body a plurality of spaced, parallel electrodes; disposing on a second surface opposite the first surface of the body a plurality of spaced, parallel electrodes alternately disposed to be between the electrodes on the first surface of said body; interconnecting the electrodes on the first surface of said body and connecting said interconnected electrodes to one pole of a polarizing voltage source; interconnecting the electrodes on the second surface and connecting said interconnected electrodes to the other pole of said polarizing voltage source, thereby to establish mainly within the body and away from the surface a longitudinally alternating polarizing field; and applying said polarizing voltage to said electrodes while said body is disposed in a gaseous medium having a relatively high value of electrical breakdown intensity.
  • a method of polarizing a ceramic, piezoelectric body comprising disposing on a first surface of the body a plurality of spaced, parallel electrodes; disposing on a second surface opposite the first surface of the body a plurality of spaced, parallel electrodes alternately disposed to be between electrodes on the first surface of said body; interconnecting the electrodes on the first surface of said body and connecting said interconnected electrodes to one pole of a polarizing voltage source; interconnecting the electrodes on the second surface and connect- References Cited in the file of this patent ing said interconnected electrodes to the other pole of UNITED STATES PATENTS said olarizing volta e source, thereb to establish mainl withi n the body and a .way from the sur face a longitudinally 4O187 CherrY 1951 alternating polarizing field; and applying said polariz- 5 2,598,707 a l June 1952,

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Manufacturing & Machinery (AREA)
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Description

1963 J. M. BRUSSAARD ETA]. 3,071,3
- METHOD OF LONGITUDINALLY PRE-POLARIZING BODIES CONSISTING 0F AT LEAST ONE LAYER OF PIEZOELECTRIC MATERIAL Filed Feb. 15, 1958 INVENTORS JAN MMRTEN BRUSSAARD AN WILLEM HEKKERT BY M AG NT United States Patent 3,071,841 METHOD OF LONGITUDINALLY PIKE-POLARIZ- ING BODIES CONSISTING OF AT LEAST ONE LAYER OF PIEZOELECTRIC MATERIAL Jan Maarten Brussaard and Jan Willem Hekkert, Eindhoven, Netherlands, assignors to North American Philips Company Inc., New York, N.Y., a corporation of Delaware Filed Feb. 13, 1958, Ser. No. 715,044 Claims priority, application Netherlands Feb. 16, 1957 2 Claims. (Cl. 29-2535) The present invention relates to a method for the longitudinal pre-polarization of bodies consisting of at least one layer of homogeneous, polycrystalline, ceramic, piezoelectric material having remanent polarization properties, which pre-polarization occurs in a medium having a high breakdown-strength, the main faces of the layers being provided with a number of parallel electrodes located at right angles or substantially at right angles to the sense of polarization, while the polarization between adjacent pairs of electrodes is of opposite sense.
Longitudinal pre-polarization means that the remanent polarization extends substantially in the direction of the longitudinal axis of the body. For this purpose, the electrodes should theoretically be provided inside the material at right angles to the main surfaces of the body, but this is difficult to realize in practice. Since electrodes are usually provided on the main surfaces, the polarization also has a transverse component, but the distance measured in the longitudinal direction between the electrodes to which the polarization is applied wholly or in part may be chosen to be so large with respect to the thickness of the body that the influence of the transverse component of the remanent polarization is, in practice, negligible. The said distance in the longitudinal direction of the body measured between the electrodes of opposite polarity is preferably twice as large as the thickness of the body.
Such a method is known from USA. patent specification 2,540,187. It has a limitation in that, due to the placement of the several electrodes, the bundle of lines of force produced during pre-polarization passes in part along the surface of the body beyond the material, which often causes arcing-over along the surface.
The method according to the invention, in which this disadvantage occurs to a much lesserdegree, consists in that one polarity of the polarization voltage is applied to the electrodes resting on one main face, and the other polarity is applied to the electrodes resting on the other mainface between each two adjacent electrodes on the first-mentioned main face. In this manner, advantage is taken from the fact that, as a result of said placement of the electrodes the whole bundle of lines of force passes through the material.
A further advantage of the method according to the invention over that according to said U.S.A. patent specification is, that for obtaining the same capacity, half the electrode surface is sufiicient, while obtaining the same output voltage.
The invention is particularly advantageous when carry ing out this method in pre-polarizing large numbers of such bodies simultaneously. As a matter of fact, in the aforesaid known method, the bodies are pre-polarized in a bath containing oil as a medium having a high breakdown-strength, a breakdown then rendering the bath unsuitable for a next polarization, so that large-scale production is not feasible. When using the method according to theinvention this disadvantage occurs to a much lesser degree in large-scale pro-polarization, since, as mentioned above, the risk of arcing-over per se has already been reduced. In so far as arcing-over is still to be feared 3,071,841 Patented Jan. 8, 1963 under these greatly improved conditions as may occur in practice, this can be met in a preferred form of the method according to the invention when using as a medium having a high breakdown-strength a gaseous medium, preferably a fluorchloromethane, for example CF CI In order that the invention may be readily carried into effect, an example will now be described with reference to the accompanying drawing, in which FIG. 1 shows a member pre-polarized according to a known method, and
FIG. 2 shows a member pre-polarized with the aid of the method according to the invention.
In FIG. 1, the reference numeral 1 designates a body of ceramic, piezo-electric material, for example BaTiO the main faces of which are provided with electrodes 2, 3, 4, 5, 6 and 7. The electrodes 2, 3 and the electrodes 3, 4 on the upper main face each constitute a pair of electrodes, similarly the electrodes 5, 6 and 6, 7 respectively each constitute a pair of electrodes on the lower main face. In this known method, the pre-polarization is effected so as to be of opposite sense between adjacent pairs of electrodes (2, 3 and 3, 4). As a result of. the placement of the several pairs of electrodes the bundle of lines of forces passes in part along the surface beyond the material, as represented schematically in FIG. 1. This often gives rise to arcing-over along the surface of the body.
FIG. 2 shows a body of ceramic, piezo-electric material the main faces of which are provided with electrodes 9, 10 and 11. The method according to the invention consists in that one polarity of the polarization voltage is applied to electrodes 9, 10 resting on the upper main face, while the other polarity is applied to the electrode 11 on the lower main face between the two upper adjacent electrodes on the upper main face. In this manner, the electrodes 9, 11 on the one hand and the electrodes 10, 11 on the other hand constitute a pair of electrodes. As a result of this disposition of electrodes the whole bundle of lines of force passes through the material.
The electrodes 9, 10, 11 may be applied to the ceramic body by the nonal techniques, such as described in the U.S.A. Patent 2,540,187 with respect to the electrodes 2, 3, 4, 5, 6, 7.
What is claimed is:
1. A method of polarizing a ceramic, piezoelectric body comprising disposing on a first surface of the body a plurality of spaced, parallel electrodes; disposing on a second surface opposite the first surface of the body a plurality of spaced, parallel electrodes alternately disposed to be between the electrodes on the first surface of said body; interconnecting the electrodes on the first surface of said body and connecting said interconnected electrodes to one pole of a polarizing voltage source; interconnecting the electrodes on the second surface and connecting said interconnected electrodes to the other pole of said polarizing voltage source, thereby to establish mainly within the body and away from the surface a longitudinally alternating polarizing field; and applying said polarizing voltage to said electrodes while said body is disposed in a gaseous medium having a relatively high value of electrical breakdown intensity.
2. A method of polarizing a ceramic, piezoelectric body comprising disposing on a first surface of the body a plurality of spaced, parallel electrodes; disposing on a second surface opposite the first surface of the body a plurality of spaced, parallel electrodes alternately disposed to be between electrodes on the first surface of said body; interconnecting the electrodes on the first surface of said body and connecting said interconnected electrodes to one pole of a polarizing voltage source; interconnecting the electrodes on the second surface and connect- References Cited in the file of this patent ing said interconnected electrodes to the other pole of UNITED STATES PATENTS said olarizing volta e source, thereb to establish mainl withi n the body and a .way from the sur face a longitudinally 4O187 CherrY 1951 alternating polarizing field; and applying said polariz- 5 2,598,707 a l June 1952,
ing voltage to said electrodes while said body is in an Wllhams July 1953 atmosphere of fluorchloromethane. Mason et a1 'T 1954 2,706,326 Mason Apr. 19; 1955 2,724,171 Wallace Nov. 22, 1955

Claims (1)

1. A METHOD OF POLARIZING A CERAMIC, PIEZOELECTRIC BODY COMPRISING DISPOSING ON A FIRST SURFACE OF THE BODY A PLURALITY OF SPACED, PARALLEL ELECTRODES; DISPOSING ON A SECOND SURFACE OPPOSITE THE FIRST SURFACE OF THE BODY A PLURALITY OF SPACED, PARALLEL ELECTRODES ALTERNATELY DISPOSED TO BE BETWEEN THE ELECTRODES ON THE FIRST SURFACE OF SAID BODY; INTERCONNECTING THE ELECTRODES ON THE FIRST SURFACE OF SAID BODY AND CONNECTING SAID INTERCONNECTED ELECTRODES TO ONE POLE OF A POLARIZING VOLTAGE SOURCE; INTERCONNECTING THE ELECTRODES ON THE SECOND SURFACE AND CONNECTING SAID INTERCONNECTED ELECTRODES TO THE OTHER POLE OF SAID POLARIZING VOLTAGE SOURCE, THEREBY TO ESTABLISH MAINLY WITHIN THE BODY AND AWAY FROM THE SURFACE A LONGITUDINALLY ALTERNATING POLARIZING FIELD; AND APPLYING SAID POLARIZING VOLTAGE TO SAID ELECTRODES WHILE SAID BODY IS DISPOSED IN A GASEOUS MEDIUM HAVING A RELATIVELY HIGH VALUE OF ELECTRICAL BREAKDOWN INTENSITY.
US715044A 1957-02-16 1958-02-13 Method of longitudinally pre-polarizing bodies consisting of at least one layer of piezoelectric material Expired - Lifetime US3071841A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284727A (en) * 1963-06-21 1966-11-08 Ibm Circular poled transducer
US3430316A (en) * 1967-05-23 1969-03-04 Motorola Inc Method for polarizing piezoelectric material
US4410823A (en) * 1981-11-13 1983-10-18 Zenith Radio Corporation Surface acoustic wave device employing reflectors
US4692654A (en) * 1984-11-02 1987-09-08 Hitachi, Ltd. Ultrasonic transducer of monolithic array type
US5225731A (en) * 1991-06-13 1993-07-06 Southwest Research Institute Solid body piezoelectric bender transducer
US5400488A (en) * 1991-09-25 1995-03-28 Tokin Corporation Method of manufacturing a piezoelectric vibrator capable of reliably preventing dielectric breakdown
US6218770B1 (en) * 1998-04-20 2001-04-17 Murata Manufacturing Co., Ltd. Piezoelectric element
US6335856B1 (en) 1999-03-05 2002-01-01 L'etat Francais, Represente Par Le Delegue Ministeriel Pour L'armement Triboelectric device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540187A (en) * 1947-12-26 1951-02-06 Zenith Radio Corp Piezoelectric transducer and method for producing same
US2598707A (en) * 1949-10-20 1952-06-03 Bell Telephone Labor Inc Electrical device embodying ferroelectric substance
US2646610A (en) * 1951-04-27 1953-07-28 Brush Dev Co Method of polarizing ceramic transducers
US2669666A (en) * 1952-06-27 1954-02-16 Bell Telephone Labor Inc Piezoelectric transducer
US2706326A (en) * 1952-04-23 1955-04-19 Bell Telephone Labor Inc Polarization process for pseudocubic ferroelectrics
US2724171A (en) * 1953-12-11 1955-11-22 John D Wallace Activation of ferroelectrics

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2540187A (en) * 1947-12-26 1951-02-06 Zenith Radio Corp Piezoelectric transducer and method for producing same
US2598707A (en) * 1949-10-20 1952-06-03 Bell Telephone Labor Inc Electrical device embodying ferroelectric substance
US2646610A (en) * 1951-04-27 1953-07-28 Brush Dev Co Method of polarizing ceramic transducers
US2706326A (en) * 1952-04-23 1955-04-19 Bell Telephone Labor Inc Polarization process for pseudocubic ferroelectrics
US2669666A (en) * 1952-06-27 1954-02-16 Bell Telephone Labor Inc Piezoelectric transducer
US2724171A (en) * 1953-12-11 1955-11-22 John D Wallace Activation of ferroelectrics

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284727A (en) * 1963-06-21 1966-11-08 Ibm Circular poled transducer
US3430316A (en) * 1967-05-23 1969-03-04 Motorola Inc Method for polarizing piezoelectric material
US4410823A (en) * 1981-11-13 1983-10-18 Zenith Radio Corporation Surface acoustic wave device employing reflectors
US4692654A (en) * 1984-11-02 1987-09-08 Hitachi, Ltd. Ultrasonic transducer of monolithic array type
US5225731A (en) * 1991-06-13 1993-07-06 Southwest Research Institute Solid body piezoelectric bender transducer
US5400488A (en) * 1991-09-25 1995-03-28 Tokin Corporation Method of manufacturing a piezoelectric vibrator capable of reliably preventing dielectric breakdown
US6218770B1 (en) * 1998-04-20 2001-04-17 Murata Manufacturing Co., Ltd. Piezoelectric element
US6335856B1 (en) 1999-03-05 2002-01-01 L'etat Francais, Represente Par Le Delegue Ministeriel Pour L'armement Triboelectric device

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