EP0264557A2 - Piezoelectric sound transducer - Google Patents

Piezoelectric sound transducer Download PDF

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Publication number
EP0264557A2
EP0264557A2 EP87111434A EP87111434A EP0264557A2 EP 0264557 A2 EP0264557 A2 EP 0264557A2 EP 87111434 A EP87111434 A EP 87111434A EP 87111434 A EP87111434 A EP 87111434A EP 0264557 A2 EP0264557 A2 EP 0264557A2
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EP
European Patent Office
Prior art keywords
support ring
metal membrane
sound transducer
membrane
distance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87111434A
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German (de)
French (fr)
Other versions
EP0264557A3 (en
Inventor
Gerd Bertl
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stettner and Co
Original Assignee
Stettner and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stettner and Co filed Critical Stettner and Co
Publication of EP0264557A2 publication Critical patent/EP0264557A2/en
Publication of EP0264557A3 publication Critical patent/EP0264557A3/en
Withdrawn legal-status Critical Current

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    • 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
    • H04R17/02—Microphones
    • 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

Definitions

  • the invention relates to a piezoceramic sound transducer with a metal membrane, which carries a ceramic disc in the middle, and with a support ring molded onto the outer circumference of the membrane.
  • the outer circumference of the metal membrane carrying a ceramic disc is inserted between the two parts of a support ring made of plastic which are to be joined concentrically, and these are ultrasonically welded to one another.
  • a support ring made of plastic which are to be joined concentrically, and these are ultrasonically welded to one another.
  • This interference source is avoided in another sound transducer, however, in that the membrane or the like on the support ring with a silicone adhesive. is glued.
  • this production proves to be too expensive - especially since a piezoceramic transducer is a mass-produced item.
  • the support ring is therefore molded onto the metal membrane.
  • these inexpensively manufactured piezoceramic sound transducers both have a large oscillation frequency range and also meet the precision requirements, a disadvantageous side effect can also be seen here.
  • the cooling process of the plastic ring is considerable Shrinkage stresses that bulge the metal membrane in one direction. If, for example, the metal membrane is arched in the other direction due to external influences, undesirable tones are produced which have a very disruptive effect on the reproduction of the tones by the sound transducer.
  • the invention has for its object to design a piezoceramic transducer of the type mentioned in such a way that it is voltage-free and an improved reproduction quality of speech and sound sequences under inexpensive manufacturing conditions and while maintaining a large vibration frequency range is made possible.
  • the invention sees a solution to this problem in that the metal membrane has at least one concentric annular groove at a distance from the supporting ring.
  • the shrinkage stresses transferred to the membrane when the plastic support or assembly ring is cooled are shifted into the area of the metal membrane between the outermost channel and the said support ring, so that the area within the existing outermost channel is relaxed.
  • the ring-shaped grooves provide the metal membrane with a higher level of stiffening.
  • the invention provides that the groove (s) is / are stamped into the metal membrane after the support ring has been molded on, in order to achieve extremely simple and, at the same time, inexpensive manufacture.
  • the groove (s) is / are stamped into the metal membrane after the support ring has been molded on, in order to achieve extremely simple and, at the same time, inexpensive manufacture.
  • the embossing of the concentric annular channels is of different depths and - when using multiple channels - the distance of these channels from one another or from the support ring is different, which results in a considerable range of setting options for the signal transmitter .
  • the first embodiment 1 has a circular metal membrane 2, in the center of which a likewise circular thin ceramic plate 3 is arranged concentrically.
  • An annular groove-like indentation 4 is introduced into the membrane 2.
  • the groove 4 is located in the comparatively large distance 5 from the outer circumference 7 of the metal membrane 2 in this embodiment.
  • This arrangement is only exemplary.
  • the gutter 4 can of course also be located further out, approximately directly on the inner edge 8 of the support ring 9 receiving the membrane 2.
  • This support ring 9 is made of plastic and is injection molded onto the outer circumference of the metal membrane 2.
  • the diameter of the ceramic plate 3 corresponds approximately to that of the inner edge of the embossed channel 4.
  • the basic principle of the embodiment according to FIG. 2 corresponds to that according to FIG. 1. Only here the metal membrane 2 carrying the metal plate 3 has two channels 4 arranged at a distance 10 from one another.

Abstract

A piezoceramic sound transducer having a metal diaphragm which carries in its centre a ceramic disc, and comprising a support ring moulded onto the outside circumference of the diaphragm, the metal diaphragm exhibiting at least one concentric annular groove at a distance from the support ring. <IMAGE>

Description

Die Erfindung bezieht sich auf einen piezokeramischen Schallwandler mit einer Metallmembran, die in ihrer Mitte eine Keramikscheibe trägt, und mit einem an dem Außenumfang der Membran angespritzten Tragring.The invention relates to a piezoceramic sound transducer with a metal membrane, which carries a ceramic disc in the middle, and with a support ring molded onto the outer circumference of the membrane.

Nach einem bekannten Verfahren zur Herstellugn eines piezo­keramischen Schallwandlers wird der Außenumfang der eine Keramikscheibe tragenden Metallmembran zwischen die beiden konzentrisch zusammenzufügenden Teile eines aus Kunststoff bestehenden Tragrings eingelegt, und diese werden mitein­ander ultraschallverschweißt. Bei dieser Ausführungsform hat sich allerdings gezeigt, daß die lediglich punktweise Verbindung der beiden Tragringelemente ein Mitschwingen der Metallmembran an den Stellen, die nicht miteinander ultraschallverschweißt sind, zuläßt. Diese Störquelle wird bei einem anderen Schallwandler allerdings dadurch vermieden, daß die Membran an dem Tragring mit einem Silikonkleber od.dgl. angeklebt wird. Diese Herstellung erweist sich je­doch - zumal es sich bei einem piezokeramischen Schallwandler um einen Massenartikel handelt - als zu aufwendig. Bei einer anderen Ausführungsform wird der Tragring deshalb an die Metallmembran angespritzt. Obwohl diese kostengünstig hergestellten piezokeramischen Schallwandler sowohl einen großen Schwingungsfrequenzbereich aufweisen als auch den Präzisionsanforderungen genügen, läßt sich auch hier ein nachteiliger Nebeneffekt erkennen. Bei dem Abkühlvor­gang des Kunststoffringes werden nämlich beträchtliche Schrumpfspannungen erzeugt, die die Metallmembran in eine Richtung vorwölben. Wird nun die Metallmembran beispiels­weise durch äußere Einflüsse in die andere Richtung ge­wölbt, so entstehen unerwünschte Töne, die sich sehr störend auf die Wiedergabe der Töne durch den Schallwand­ler auswirken.According to a known method for producing a piezoceramic sound transducer, the outer circumference of the metal membrane carrying a ceramic disc is inserted between the two parts of a support ring made of plastic which are to be joined concentrically, and these are ultrasonically welded to one another. In this embodiment, however, it has been shown that the only point-by-point connection of the two support ring elements allows the metal membrane to vibrate at the points which are not ultrasonically welded to one another. This interference source is avoided in another sound transducer, however, in that the membrane or the like on the support ring with a silicone adhesive. is glued. However, this production proves to be too expensive - especially since a piezoceramic transducer is a mass-produced item. In another embodiment, the support ring is therefore molded onto the metal membrane. Although these inexpensively manufactured piezoceramic sound transducers both have a large oscillation frequency range and also meet the precision requirements, a disadvantageous side effect can also be seen here. The cooling process of the plastic ring is considerable Shrinkage stresses that bulge the metal membrane in one direction. If, for example, the metal membrane is arched in the other direction due to external influences, undesirable tones are produced which have a very disruptive effect on the reproduction of the tones by the sound transducer.

Der Erfindung liegt die Aufgabe zugrunde, einen piezokera­mischen Schallwandler der eingangs genannten Art so auszu­gestalten, daß er spannungsfrei ist und eine verbesserte Wiedergabequalität von Sprache und Tonfolgen unter kosten­günstigen Herstellungsbedingungen und unter gleichzeitiger Erhaltung eines großen Schwingungsfrequenzbereiches ermög­licht wird. Die Lösung dieses Problems sieht die Erfindung darin, daß die Metallmembran in Abstand von dem Tragring wenigstens eine konzentrische ringförmige Rinne aufweist.The invention has for its object to design a piezoceramic transducer of the type mentioned in such a way that it is voltage-free and an improved reproduction quality of speech and sound sequences under inexpensive manufacturing conditions and while maintaining a large vibration frequency range is made possible. The invention sees a solution to this problem in that the metal membrane has at least one concentric annular groove at a distance from the supporting ring.

Durch diese Maßnahme werden die bei der Abkühlung des aus Kunststoff bestehenden Trag- bzw. Montagerings auf die Mem­bran übertragenen Schrumpfverspannungen in den Bereich der Metallmembran zwischen der jeweils äußersten Rinne und dem besagten Tragring verlagert, so daß das Gebiet innerhalb der vorhandenen äußersten Rinne entspannt wird. Zudem erhält die Metallmembran insgesamt durch die ringförmig ausgebildeten Rinnen eine höhere Aussteifung.As a result of this measure, the shrinkage stresses transferred to the membrane when the plastic support or assembly ring is cooled are shifted into the area of the metal membrane between the outermost channel and the said support ring, so that the area within the existing outermost channel is relaxed. In addition, the ring-shaped grooves provide the metal membrane with a higher level of stiffening.

In weiterer Ausgestaltung sieht die Erfindung vor, daß die Rinne/n nach dem Anspritzen des Tragrings in die Metall­membran eingeprägt ist/sind, um so zum einen eine extrem ein­fache und zugleich kostengünstige Fertigung zu erreichen. Zum anderen ist es auf diese Art und Weise im Zusammenwirken mit der Verlagerung der herstellungsbedingten Spannungen in Außenrandgebiete der Metallmembran möglich, auftretende Fre­quenzspitzen abzubauen und die gewünschte einheitliche Fre­quenzbandbreite auf überaus einfache Weise zu erzielen.In a further embodiment, the invention provides that the groove (s) is / are stamped into the metal membrane after the support ring has been molded on, in order to achieve extremely simple and, at the same time, inexpensive manufacture. On the other hand, it is possible in this way in conjunction with the shift of the production-related tensions in the outer peripheral regions of the metal membrane to reduce occurring frequency peaks and to achieve the desired uniform frequency bandwidth in a very simple manner.

Schließlich liegt es weiter im Rahmen der Erfindung, daß die Prägung der konzentrischen ringförmigen Rinnen unter­schiedlich tief und - bei Anwendung mehrerer Rinnen - der Abstand dieser Rinnen zueinander bzw. zu dem Tragring unter­schiedlich groß ist, woraus sich eine beachtliche Spannweite von Einstellmöglichkeiten für den Signalgeber ergeben.Finally, it is further within the scope of the invention that the embossing of the concentric annular channels is of different depths and - when using multiple channels - the distance of these channels from one another or from the support ring is different, which results in a considerable range of setting options for the signal transmitter .

Weitere Merkmale, Einzelheiten und Vorteile der Erfindung ergeben sich aus der folgenden Beschreibung einiger bevor­zugter Ausführungsformen der Erfindung sowie anhand der Zeichnung. Hierbei zeigen:

  • Fig. 1 eine Längsschnitt durch eine erste Ausführungsform des Schallwandlers und
  • Fig. 2 eine andere Ausführungsform in perspektivischer Dar­stellung.
Further features, details and advantages of the invention will become apparent from the following description of some preferred embodiments of the invention and from the drawing. Here show:
  • Fig. 1 shows a longitudinal section through a first embodiment of the sound transducer and
  • Fig. 2 shows another embodiment in perspective.

Der Schallwandler 1 nach Fig. 1 weist eine kreisförmige Metallmembran 2 auf, in deren Mitte konzentrisch ein ebenfalls kreisförmiges dünnes Keramikplättchen 3 angeordnet ist. In die Membran 2 ist eine ringförmige rinnenartige Einprägung 4 eingebracht. Die Rinne 4 befindet sich in dem bei dieser Ausführungsform vergleichsweise großen Abstand 5 vom Außenum­fang 7 der Metallmembran 2. Diese Anordnung ist lediglich bei­spielhaft. Die Rinne 4 kann selbstverständlich auch weiter außen liegen, und zwar bis etwa unmittelbar an der Innenkante 8 des die Membran 2 aufnehmenden Tragrings 9. Dieser Tragring 9 besteht aus Kunststoff und ist im Wege des Spritzgießens an den Außenumfang der Metallmembran 2 angeformt. Der Durchmesser des Keramikplättchens 3 entspricht bei der Ausführungsform nach Fig. 1 etwa demjenigen des Innenrandes der eingeprägten Rinne 4.1 has a circular metal membrane 2, in the center of which a likewise circular thin ceramic plate 3 is arranged concentrically. An annular groove-like indentation 4 is introduced into the membrane 2. The groove 4 is located in the comparatively large distance 5 from the outer circumference 7 of the metal membrane 2 in this embodiment. This arrangement is only exemplary. The gutter 4 can of course also be located further out, approximately directly on the inner edge 8 of the support ring 9 receiving the membrane 2. This support ring 9 is made of plastic and is injection molded onto the outer circumference of the metal membrane 2. In the embodiment according to FIG. 1, the diameter of the ceramic plate 3 corresponds approximately to that of the inner edge of the embossed channel 4.

Die Ausführungsform nach Fig. 2 entspricht im Grundprinzip derjenigen nach Fig. 1. Nur weist hier die das Metallplätt­chen 3 tragende Metallbran 2 zwei im Abstand 10 voneinander angeordnete Rinnen 4 auf.The basic principle of the embodiment according to FIG. 2 corresponds to that according to FIG. 1. Only here the metal membrane 2 carrying the metal plate 3 has two channels 4 arranged at a distance 10 from one another.

In beiden Fällen sind die Rinnen 4 nach dem Anspritzen des Tragrings 9 an die Metallmembran 2 in diese eingeprägt worden. Auf diese Weise werden die beim Schrumpfen des Kunststoffes des angespritzten Tragrings 9 auftretenden Verspannungen aus der Membran genommen, so daß diese voll funktionsfähig ist und eine einwandfreie Tonwiedergabe gewährleisten kann.In both cases, the grooves 4 have been stamped into the metal membrane 2 after the support ring 9 has been molded onto it. In this way, the stresses that occur when the plastic of the molded support ring 9 shrinks are removed from the membrane, so that it is fully functional and can ensure flawless sound reproduction.

Claims (4)

1. Piezokeramischer Schallwandler mit einer Metallmembran, die in ihrer Mitte eine Keramikscheibe trägt, und mit einem an dem Außenumfang der Membran angespritzten Trag­ring, dadurch gekennzeichnet, daß die Metallmembran (2) in Abstand von dem Tragring (9) wenigstens eine konzen­trische ringförmige Rinne (4) aufweist.1. Piezoceramic sound transducer with a metal membrane, which carries a ceramic disk in its center, and with a support ring molded onto the outer circumference of the membrane, characterized in that the metal membrane (2) at a distance from the support ring (9) has at least one concentric annular groove ( 4). 2. Schallwandler nach Anspruch 1, dadurch gekennzeichnet, daß die Rinne (4) nach dem Anspritzen des Tragrings in die Metallmembran (2) eingeprägt ist.2. A transducer according to claim 1, characterized in that the groove (4) is stamped into the metal membrane (2) after the support ring has been molded on. 3. Schallwandler nach Anspruch 1 oder 2, dadurch gekennzeich net, daß die Prägung der Rinnen (4) unterschiedlich tief ist.3. A transducer according to claim 1 or 2, characterized in that the embossing of the channels (4) is of different depths. 4. Schallwandler nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Abstand (5) der Rinne (4) vom Tragring (9) oder der Abstand (10) mehrerer Rinnen (4) voneinander unterschiedlich groß ist.4. Sound transducer according to one of claims 1 to 3, characterized in that the distance (5) of the channel (4) from the support ring (9) or the distance (10) of several channels (4) from each other is different.
EP87111434A 1986-08-27 1987-08-07 Piezoelectric sound transducer Withdrawn EP0264557A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863629093 DE3629093A1 (en) 1986-08-27 1986-08-27 PIEZOCERAMIC SOUND CONVERTER
DE3629093 1986-08-27

Publications (2)

Publication Number Publication Date
EP0264557A2 true EP0264557A2 (en) 1988-04-27
EP0264557A3 EP0264557A3 (en) 1989-12-06

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ID=6308271

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87111434A Withdrawn EP0264557A3 (en) 1986-08-27 1987-08-07 Piezoelectric sound transducer

Country Status (5)

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EP (1) EP0264557A3 (en)
JP (1) JPS6367900A (en)
KR (1) KR900006323B1 (en)
DE (1) DE3629093A1 (en)
IL (1) IL83648A0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2232321A (en) * 1989-03-07 1990-12-05 Mitsubishi Mining & Cement Co Focusing piezoelectric transducer
GB2348564A (en) * 1999-04-01 2000-10-04 Thomson Marconi Sonar Limited An acoustic transducer for underwater use

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3360558B2 (en) * 1997-01-06 2002-12-24 株式会社村田製作所 Piezoelectric electroacoustic transducer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR854121A (en) * 1938-12-14 1940-04-05 Csf Improvements to electromechanical vibrating devices
DE1112548B (en) * 1960-02-01 1961-08-10 Krone Kg Speech capsule for telecommunication purposes
US4449019A (en) * 1980-11-10 1984-05-15 Murata Manufacturing Co., Ltd. Piezoelectric loudspeaker

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056742A (en) * 1976-04-30 1977-11-01 Tibbetts Industries, Inc. Transducer having piezoelectric film arranged with alternating curvatures
FR2394512A1 (en) * 1977-06-14 1979-01-12 Rhone Poulenc Ind PROCESS FOR THE SEPARATION OF ACRYLIC ACID FROM ITS SOLUTIONS IN TRI-N-BUTYL PHOSPHATE
DE3041742C2 (en) * 1980-11-05 1982-10-28 Siemens AG, 1000 Berlin und 8000 München Airborne sounder

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR854121A (en) * 1938-12-14 1940-04-05 Csf Improvements to electromechanical vibrating devices
DE1112548B (en) * 1960-02-01 1961-08-10 Krone Kg Speech capsule for telecommunication purposes
US4449019A (en) * 1980-11-10 1984-05-15 Murata Manufacturing Co., Ltd. Piezoelectric loudspeaker

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2232321A (en) * 1989-03-07 1990-12-05 Mitsubishi Mining & Cement Co Focusing piezoelectric transducer
GB2348564A (en) * 1999-04-01 2000-10-04 Thomson Marconi Sonar Limited An acoustic transducer for underwater use
US6404106B1 (en) 1999-04-01 2002-06-11 Thales Underwater Systems Limited Pressure tolerant transducer
GB2348564B (en) * 1999-04-01 2003-06-18 Thomson Marconi Sonar Ltd Transducers
EP1041537A3 (en) * 1999-04-01 2004-12-01 Thales Underwater Systems Limited Pressure tolerant transducer

Also Published As

Publication number Publication date
JPS6367900A (en) 1988-03-26
KR900006323B1 (en) 1990-08-28
EP0264557A3 (en) 1989-12-06
IL83648A0 (en) 1988-01-31
KR880003535A (en) 1988-05-17
DE3629093A1 (en) 1988-03-10

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