WO2002091492A2 - Electrostrictive bending transducer - Google Patents

Electrostrictive bending transducer Download PDF

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Publication number
WO2002091492A2
WO2002091492A2 PCT/GB2002/002033 GB0202033W WO02091492A2 WO 2002091492 A2 WO2002091492 A2 WO 2002091492A2 GB 0202033 W GB0202033 W GB 0202033W WO 02091492 A2 WO02091492 A2 WO 02091492A2
Authority
WO
WIPO (PCT)
Prior art keywords
transducer according
bending transducer
electrode
electrostrictive
bending
Prior art date
Application number
PCT/GB2002/002033
Other languages
French (fr)
Other versions
WO2002091492A3 (en
Inventor
Charles Bream
Graham Bank
Original Assignee
New Transducers Limited
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 New Transducers Limited filed Critical New Transducers Limited
Publication of WO2002091492A2 publication Critical patent/WO2002091492A2/en
Publication of WO2002091492A3 publication Critical patent/WO2002091492A3/en

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Classifications

    • 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
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
    • 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
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/875—Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins

Definitions

  • the present invention relates to electrostrictive bending transducers and particularly but not exclusively to piezoelectric ceramic actuators.
  • a conventional piezoelectric bending actuator 1 is illustrated in figure 1: a first layer 2 of piezoelectric ceramic such as lead zirconium titanate (PZT) is polarised - as shown by arrows 3 - in its thickness direction, perpendicular to the plane of the layer, and is provided with electrodes 4,5 on its upper and lower surfaces.
  • PZT lead zirconium titanate
  • Layer 2 is attached by means of an adhesive bond layer 6 to a second layer of material 7 which can be electrically inactive (such as a thick brass foil) in which case the resulting construction is known as a unimorph, or which may also comprise piezoelectric material and be provided with electrodes 8,9, whence the construction is known as a bimorph.
  • a second layer of material 7 which can be electrically inactive (such as a thick brass foil) in which case the resulting construction is known as a unimorph, or which may also comprise piezoelectric material and be provided with electrodes 8,9, whence the construction is known as a bimorph.
  • an electric field of appropriate polarity across electrodes 4,5 will cause layer 2 to contract in its thickness direction and expand relative to the second layer in directions parallel to the plane of the layer. This in turn will cause the actuator as a whole to bend as indicated by dashed lines in figure 1, resulting in a movement of the top-most point 10 of the actuator relative to the bottom-most point 11 which can be harnessed for actuation purposes.
  • an appropriate electric field can be applied via electrodes to cause it to contract, thereby increasing the degree of bending and thus the amount of actuation movement.
  • actuators of the kind described above are well suited for use in loudspeakers of the distributed mode acoustic radiator type due to the fact that their mechanical impedance is well matched to that of the loudspeaker, ensuring efficient operation.
  • loudspeakers known for example from WO97/09842
  • a panel member as a resonant acoustic radiator relying on bending wave action and a bending transducer coupled to the panel member so as to cause bending waves therein.
  • the natural bending frequency of the actuator is desirable for the natural bending frequency of the actuator to be low so as to allow effective reproduction of bass tones by the loudspeaker.
  • this is achieved by reducing the moment of inertia (also known as the second moment of area) of the actuator construction, in particular by minimising the thickness of the electrode layers.
  • Such thin layers are conventionally formed by metal deposition, sputtering or similar techniques or may be applied by screen printing with metal-loaded ink followed by consolidation at high temperature.
  • the loudspeaker may be subject to shock loading. It is desirable that the transducer continue to operate after such shock loading and the present invention arises from the recognition of the need for a transducer to continue operating even after its typically brittle - ceramic layer has sustained a fracture.
  • the present invention consists in a bending transducer comprising an electrostrictive member and electrodes for transmitting an electric field to or from said member and which do not contribute significantly to the bending stiffness of said electrostrictive member; wherein an electrode is capable of a yield strain significantly greater than that of the electrostrictive member.
  • the electrode will stretch - but not yield / break / rupture - to accommodate any deformation of the electrostrictive member that may cause a fracture in that member brought about e.g. by a shock load. Electrical continuity will therefore be maintained and the entire ceramic member will continue to operate in spite of being fractured.
  • a method of manufacture of a transducer comprising an electrostrictive member and electrodes for transmitting an electric field to or from said member, the method comprising the steps of: providing an electrostrictive member having a surface; and adhering an electrically-conductive foil to said surface.
  • FIG. 2 shows a schematic, cross-sectional view of a transducer according to the invention.
  • the transducer 20 of the invention comprises two layers, one of which is a piezoelectric ceramic element 2 polarised in its thickness direction as indicated by arrows 3.
  • electrodes 4,5 which are used both in the application of a high electric field to polarise the initially unpolarised piezoelectric ceramic and in the application of a lower electric field to cause the piezoelectric ceramic material to expand / contract in the polarisation direction (and also perpendicular to the polarisation direction due to Poisson's ratio effects).
  • the other layer 7 may also comprise electrostrictive material polarised in the opposite sense to layer 2 so as to deform in the opposite sense to layer 2 when subject to an electric field.
  • a further electrode construction 23 comprising an electrically conductive foil 21 and a conductive adhesive layer 22. This ensures that any actuation charge delivered (via electrical connection 24) to the foil can be connected to the whole of the piezoelectric element via electrode 4, even if there is loss of continuity over the whole surface of the ceramic member as a result of fracture.
  • a similar further electrode is applied to the bottom of electrode 11.
  • the properties of the further electrode 23 are chosen to avoid any significant increase in the overall stiffness of the transducer which would otherwise impact negatively on its dynamic response.
  • the foil thickness and the shear modulus of the adhesive layer are kept low.
  • the foil is metallic, preferably copper, and like the adhesive layers has a thickness of 38 ⁇ m. This, together with the fact that the elastic modulus of the copper foil and the ceramic are similar, ensure that the further electrode increases the bending stiffness of the basic ceramic "sandwich" 2,5,6,8,7 by no more than 25%.
  • the properties of the further electrode are also chosen so as to provide a yield strain significantly greater than that of the electrostrictive ceramic.
  • the copper foil has a yield strain of 1%: i.e. at least around half an order of magnitude greater than the 0.2% yield strain of the ceramic.
  • the electrode comprises a first layer which is electrically conductive in a direction normal to a surface of said electrostrictive member to which the electrode is attached and a second layer electrically conductive in a direction parallel to the surface, the first layer being capable of a yield strain significantly greater than that of the electrostrictive member.
  • the first - preferably adhesive - layer can take up the difference in extension between the conductive element 21 and the piezo element 2 that may occur when the latter element fractures as a result of a shock loading.
  • a particularly preferred construction uses a pressure-sensitive adhesive, advantageously in the form of a foil-lined pressure sensitive tape in which the adhesive is conductive through its thickness.
  • a compliant adhesive ensures that the foil electrode is mechanically 'isolated' from the piezoelectric element, thereby preventing / restricting an overall increase in stiffness of the transducer .
  • a conductive foil as the further electrode may obviate the need for an intermediate conductive layer.
  • an electrode formed remotely of the piezoelectric ceramic, e.g. by rolling, and thereafter applied to the piezoelectric ceramic will typically have a material structure that has a greater yield strain than the material structure of conventional electrodes as formed by deposition e.g. sputtering.
  • conventional deposited electrodes may not be required at all: the conductive foil may serve for the application of both polarisation and actuation electric fields.
  • the intermediate layer having a high yield strain may be sufficiently conductive in the direction parallel to the plane of the piezoelectric element 2 as to obviate the need for a conductive foil.
  • the intermediate layer 22 need only be sufficiently conductive in a direction normal to the plane of the piezoelectric element 2, allowing the foil 21 to distribute the charge over the whole area of the transducer.
  • a transducer according to the invention preferably comprises two layers, one of which is an electrostrictive member. It will also be appreciated that whilst the invention has been described in the context of a device having two electrically active layers, it is equally applicable to devices in which one of the two layers is electrically inactive.
  • the method disclosed above is also simpler to implement than conventional deposition techniques which require costly vacuum equipment.
  • the method is particularly advantageous if the foil is first provided with an adhesive coating, which itself may have an elastic modulus significantly lower and a yield strain significantly higher than the corresponding values of the electrostrictive material.
  • the invention can be applied to transducers that convert movement to electricity, e.g. in microphone applications, as well as in the actuator applications described above.

Abstract

A bending transducer (20) comprises an electrostrictive ceramic member (2) and electrodes (4, 5) for transmitting an electric field to or from said member and which do not contribute significantly to the bending stiffness of said electrostrictive ceramic member. At least one of the electrodes (4, 5) is capable of a yield strain significantly greater than that of the electrostrictive ceramic member (2); thereby accommodating any deformation of the electrostrictive member (2) that might cause a fracture of that member. In this way, electrical continuity is maintained. The bending transducer is suited to loudspeaker applications.

Description

TITLE: ELECTROSTRICTIVE BENDING TRANSDUCER
DESCRIPTION
The present invention relates to electrostrictive bending transducers and particularly but not exclusively to piezoelectric ceramic actuators. The construction of a conventional piezoelectric bending actuator 1 is illustrated in figure 1: a first layer 2 of piezoelectric ceramic such as lead zirconium titanate (PZT) is polarised - as shown by arrows 3 - in its thickness direction, perpendicular to the plane of the layer, and is provided with electrodes 4,5 on its upper and lower surfaces. Layer 2 is attached by means of an adhesive bond layer 6 to a second layer of material 7 which can be electrically inactive (such as a thick brass foil) in which case the resulting construction is known as a unimorph, or which may also comprise piezoelectric material and be provided with electrodes 8,9, whence the construction is known as a bimorph.
As is well known, application of an electric field of appropriate polarity across electrodes 4,5 will cause layer 2 to contract in its thickness direction and expand relative to the second layer in directions parallel to the plane of the layer. This in turn will cause the actuator as a whole to bend as indicated by dashed lines in figure 1, resulting in a movement of the top-most point 10 of the actuator relative to the bottom-most point 11 which can be harnessed for actuation purposes. Where bottom layer is also active, an appropriate electric field can be applied via electrodes to cause it to contract, thereby increasing the degree of bending and thus the amount of actuation movement.
As is known, actuators of the kind described above are well suited for use in loudspeakers of the distributed mode acoustic radiator type due to the fact that their mechanical impedance is well matched to that of the loudspeaker, ensuring efficient operation. Such loudspeakers, known for example from WO97/09842
(incorporated herein by reference) , comprise a panel member as a resonant acoustic radiator relying on bending wave action and a bending transducer coupled to the panel member so as to cause bending waves therein.
In such applications, it is desirable for the natural bending frequency of the actuator to be low so as to allow effective reproduction of bass tones by the loudspeaker. In accordance with conventional bending theory, this is achieved by reducing the moment of inertia (also known as the second moment of area) of the actuator construction, in particular by minimising the thickness of the electrode layers. Such thin layers are conventionally formed by metal deposition, sputtering or similar techniques or may be applied by screen printing with metal-loaded ink followed by consolidation at high temperature.
Furthermore, in many - typically consumer applications, the loudspeaker may be subject to shock loading. It is desirable that the transducer continue to operate after such shock loading and the present invention arises from the recognition of the need for a transducer to continue operating even after its typically brittle - ceramic layer has sustained a fracture.
Accordingly, the present invention consists in a bending transducer comprising an electrostrictive member and electrodes for transmitting an electric field to or from said member and which do not contribute significantly to the bending stiffness of said electrostrictive member; wherein an electrode is capable of a yield strain significantly greater than that of the electrostrictive member.
As a result of having a yield strain significantly greater than that of the electrostrictive member, the electrode will stretch - but not yield / break / rupture - to accommodate any deformation of the electrostrictive member that may cause a fracture in that member brought about e.g. by a shock load. Electrical continuity will therefore be maintained and the entire ceramic member will continue to operate in spite of being fractured.
There is also disclosed a method of manufacture of a transducer comprising an electrostrictive member and electrodes for transmitting an electric field to or from said member, the method comprising the steps of: providing an electrostrictive member having a surface; and adhering an electrically-conductive foil to said surface.
Further advantageous embodiments of the invention are set out in the description and dependent claims. The invention will now be described by way of example by reference to figure 2 which shows a schematic, cross-sectional view of a transducer according to the invention.
As in the conventional arrangement described above, the transducer 20 of the invention comprises two layers, one of which is a piezoelectric ceramic element 2 polarised in its thickness direction as indicated by arrows 3. On opposite surfaces of the element 2 are arranged electrodes 4,5 which are used both in the application of a high electric field to polarise the initially unpolarised piezoelectric ceramic and in the application of a lower electric field to cause the piezoelectric ceramic material to expand / contract in the polarisation direction (and also perpendicular to the polarisation direction due to Poisson's ratio effects).
As known from the conventional arrangement, the other layer 7 may also comprise electrostrictive material polarised in the opposite sense to layer 2 so as to deform in the opposite sense to layer 2 when subject to an electric field.
Unlike the conventional construction, however, there is arranged on top of electrode 4 a further electrode construction 23 comprising an electrically conductive foil 21 and a conductive adhesive layer 22. This ensures that any actuation charge delivered (via electrical connection 24) to the foil can be connected to the whole of the piezoelectric element via electrode 4, even if there is loss of continuity over the whole surface of the ceramic member as a result of fracture. A similar further electrode is applied to the bottom of electrode 11.
The properties of the further electrode 23 are chosen to avoid any significant increase in the overall stiffness of the transducer which would otherwise impact negatively on its dynamic response. In particular, the foil thickness and the shear modulus of the adhesive layer are kept low. In the example shown, the foil is metallic, preferably copper, and like the adhesive layers has a thickness of 38μm. This, together with the fact that the elastic modulus of the copper foil and the ceramic are similar, ensure that the further electrode increases the bending stiffness of the basic ceramic "sandwich" 2,5,6,8,7 by no more than 25%.
The properties of the further electrode are also chosen so as to provide a yield strain significantly greater than that of the electrostrictive ceramic. In the example shown, the copper foil has a yield strain of 1%: i.e. at least around half an order of magnitude greater than the 0.2% yield strain of the ceramic.
Yet further advantage is achieved by selection of an adhesive having a high yield strain and a shear modulus very much less than the corresponding elastic modulus of the copper. In such a construction, the electrode comprises a first layer which is electrically conductive in a direction normal to a surface of said electrostrictive member to which the electrode is attached and a second layer electrically conductive in a direction parallel to the surface, the first layer being capable of a yield strain significantly greater than that of the electrostrictive member. In such an arrangement, the first - preferably adhesive - layer can take up the difference in extension between the conductive element 21 and the piezo element 2 that may occur when the latter element fractures as a result of a shock loading.
A particularly preferred construction uses a pressure-sensitive adhesive, advantageously in the form of a foil-lined pressure sensitive tape in which the adhesive is conductive through its thickness. As mentioned above, the use of a compliant adhesive ensures that the foil electrode is mechanically 'isolated' from the piezoelectric element, thereby preventing / restricting an overall increase in stiffness of the transducer .
It will be appreciated that the present invention has been described by way of examples only and that a wide variety of modifications can be made without departing from the scope of the invention as defined in the claims.
In particular, the use of a conductive foil as the further electrode may obviate the need for an intermediate conductive layer. This is because such an electrode, formed remotely of the piezoelectric ceramic, e.g. by rolling, and thereafter applied to the piezoelectric ceramic will typically have a material structure that has a greater yield strain than the material structure of conventional electrodes as formed by deposition e.g. sputtering. Indeed, conventional deposited electrodes may not be required at all: the conductive foil may serve for the application of both polarisation and actuation electric fields.
Alternatively, the intermediate layer having a high yield strain may be sufficiently conductive in the direction parallel to the plane of the piezoelectric element 2 as to obviate the need for a conductive foil. Typically, however, the intermediate layer 22 need only be sufficiently conductive in a direction normal to the plane of the piezoelectric element 2, allowing the foil 21 to distribute the charge over the whole area of the transducer.
A transducer according to the invention preferably comprises two layers, one of which is an electrostrictive member. It will also be appreciated that whilst the invention has been described in the context of a device having two electrically active layers, it is equally applicable to devices in which one of the two layers is electrically inactive.
The method disclosed above, particularly the step of adhering an electrically-conductive foil to the surface of the electrostrictive element, is also simpler to implement than conventional deposition techniques which require costly vacuum equipment. The method is particularly advantageous if the foil is first provided with an adhesive coating, which itself may have an elastic modulus significantly lower and a yield strain significantly higher than the corresponding values of the electrostrictive material.
It will also be appreciated that although the invention has been described in the context of - and indeed is particularly suited to an electrically-active ceramic - in particular a piezoelectric ceramic, the invention may be used with other, non-ceramic materials susceptible to the problems outlined at the beginning of this document. Such materials (e.g. quartz or rochelle salt) , although less active than PZT ceramic, nevertheless undergo a change in dimension when subject to an electric field (which is the definition of the term electrostrictive) and as such could be used in an actuator.
Furthermore, the invention can be applied to transducers that convert movement to electricity, e.g. in microphone applications, as well as in the actuator applications described above.

Claims

1. A bending transducer comprising an electrostrictive member and electrodes for transmitting an electric field to or from said member and which do not contribute significantly to the bending stiffness of said electrostrictive member; wherein an electrode is capable of a yield strain significantly greater than that of the electrostrictive member.
2. Bending transducer according to claim 1, wherein said electrostrictive member comprises ceramic material.
3. Bending transducer according to claim 2, wherein said electrostrictive member comprises piezoelectric ceramic material.
4. Bending transducer according to any previous claim and comprising two layers, one of which is said electrostrictive member.
5. Bending transducer according to claim 4, wherein the other of said two layers is electrically inactive.
6. Bending transducer according to claim 4, wherein the other of said two layers comprises electrostrictive material, the two layers being configured to deform in opposite senses when subject to an electric field.
7. Bending transducer according to claim 6, wherein said two layers are polarised in their thickness directions.
8. Bending transducer according to any previous claim, wherein said electrode is capable of a yield strain of at least approximately half an order of magnitude greater than that of the electrostrictive member.
9. Bending transducer according to claim 8, wherein said electrode comprises an electrically-conductive foil applied to said electrostrictive member.
10. Bending transducer according to claim 9, wherein said electrode is metallic.
11. Bending transducer according to claim 10, wherein said electrode is made of copper.
12. Bending transducer according to any previous claim, wherein said electrode comprises a first layer which is electrically conductive in a direction normal to a surface of said electrostrictive member to which the electrode is attached, and a second layer electrically conductive in a direction parallel to said surface, said first layer being capable of a yield strain significantly greater than that of the electrostrictive member.
13. Bending transducer according to claim 12, wherein said second layer is an adhesive layer joining said electrode to said electrostrictive member.
14. Bending transducer according to claim 13, wherein said adhesive layer is pressure sensitive.
15. Bending transducer according to claim 14, wherein said electrode is foil-lined pressure sensitive adhesive tape.
16. Loudspeaker comprising a panel member as resonant acoustic radiator relying on bending wave action and a bending transducer according to any of claims 1 to 15 and coupled to the panel member to cause bending waves therein.
PCT/GB2002/002033 2001-05-04 2002-05-03 Electrostrictive bending transducer WO2002091492A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0111003.0 2001-05-04
GBGB0111003.0A GB0111003D0 (en) 2001-05-04 2001-05-04 Electrostrictive transducer and method of manufacture thereof

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WO2002091492A2 true WO2002091492A2 (en) 2002-11-14
WO2002091492A3 WO2002091492A3 (en) 2003-05-08

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013044909A1 (en) * 2011-09-28 2013-04-04 Eads Deutschland Gmbh Diaphragm arrangement for generating sound
WO2017011578A1 (en) * 2015-07-14 2017-01-19 uBeam Inc. Laminate material bonding
CN108666415A (en) * 2018-05-21 2018-10-16 哈尔滨工业大学 A kind of preparation method and application of polymer matrix piezoelectric bimorph
CN117135990A (en) * 2023-01-31 2023-11-28 荣耀终端有限公司 Piezoelectric device, sound generating device and electronic equipment

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3622815A (en) * 1970-03-25 1971-11-23 Motorola Inc High reliability ceramic bender
WO2001005189A2 (en) * 1999-07-08 2001-01-18 New Transducers Limited Bending wave panel speaker and method of driving such a speaker

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63239879A (en) * 1987-03-27 1988-10-05 Hitachi Denshi Ltd Piezoelectric bimorph
JPH04316377A (en) * 1991-04-15 1992-11-06 Ngk Spark Plug Co Ltd Composite piezoelectric device
JP3405618B2 (en) * 1995-04-11 2003-05-12 松下電器産業株式会社 Bimorph piezoelectric actuator

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3622815A (en) * 1970-03-25 1971-11-23 Motorola Inc High reliability ceramic bender
WO2001005189A2 (en) * 1999-07-08 2001-01-18 New Transducers Limited Bending wave panel speaker and method of driving such a speaker

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 013, no. 044 (E-710), 31 January 1989 (1989-01-31) -& JP 63 239879 A (HITACHI ELECTRONICS LTD), 5 October 1988 (1988-10-05) *
PATENT ABSTRACTS OF JAPAN vol. 017, no. 150 (E-1339), 25 March 1993 (1993-03-25) & JP 04 316377 A (NGK SPARK PLUG CO LTD), 6 November 1992 (1992-11-06) -& JP 04 316377 A (NGK SPARK PLUG CO LTD) 6 November 1992 (1992-11-06) *
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 03, 31 March 1997 (1997-03-31) & JP 08 288564 A (MATSUSHITA ELECTRIC IND CO LTD), 1 November 1996 (1996-11-01) -& JP 08 288564 A (MATSUSHITA ELECTRIC IND CO LTD) 1 November 1996 (1996-11-01) *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013044909A1 (en) * 2011-09-28 2013-04-04 Eads Deutschland Gmbh Diaphragm arrangement for generating sound
CN103828394A (en) * 2011-09-28 2014-05-28 Eads德国有限公司 Diaphragm arrangement for generating sound
US9113248B2 (en) 2011-09-28 2015-08-18 Airbus Defence and Space GmbH Diaphragm arrangement for generating sound
WO2017011578A1 (en) * 2015-07-14 2017-01-19 uBeam Inc. Laminate material bonding
US9821541B2 (en) 2015-07-14 2017-11-21 uBeam Inc. Laminate material bonding
US10322570B2 (en) 2015-07-14 2019-06-18 uBeam Inc. Laminate material bonding
CN108666415A (en) * 2018-05-21 2018-10-16 哈尔滨工业大学 A kind of preparation method and application of polymer matrix piezoelectric bimorph
CN108666415B (en) * 2018-05-21 2021-08-06 哈尔滨工业大学 Preparation method and application of polymer-based piezoelectric bimorph
CN117135990A (en) * 2023-01-31 2023-11-28 荣耀终端有限公司 Piezoelectric device, sound generating device and electronic equipment

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