WO1987007767A1 - Transducteurs piezoelectriques - Google Patents

Transducteurs piezoelectriques Download PDF

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Publication number
WO1987007767A1
WO1987007767A1 PCT/GB1987/000394 GB8700394W WO8707767A1 WO 1987007767 A1 WO1987007767 A1 WO 1987007767A1 GB 8700394 W GB8700394 W GB 8700394W WO 8707767 A1 WO8707767 A1 WO 8707767A1
Authority
WO
WIPO (PCT)
Prior art keywords
transducer
conductive
piezoelectric
sheet
film
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.)
Ceased
Application number
PCT/GB1987/000394
Other languages
English (en)
Inventor
Richard Brown
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.)
Syrinx Innovations Ltd
Original Assignee
Syrinx Innovations Ltd
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 Syrinx Innovations Ltd filed Critical Syrinx Innovations Ltd
Publication of WO1987007767A1 publication Critical patent/WO1987007767A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors

Definitions

  • This invention relates to piezoelectric transducers, particularly but not exclusively those making use of polymeric piezoelectric materials.
  • PVDF polyvinylidene fluoride
  • Known PVDF films can exhibit high piezoelectr activity, for example those produced from a homopolymer of vinylidene fluoride by melt extrusion followed by mechanical stretching to produce orientation and electrical polarisation or poling in a high intensity field.
  • An example of such a material is KYNAR (trade mark) film by Pennwalt Corporation.
  • KYNAR trade mark
  • Such materials produce electrical energy when deformed by bending, stretching or compression, or can be operated in reverse by applying a voltage to produce mechanical movement.
  • Electrodes When used as a transducer, it has hitherto been the practice to provide electrodes on the surfaces of the PVDF film, which electrodes couple the charge produced in the film on deformation to an external circuit, thereby producing current flow in the circuit.
  • Such electrodes may be applied to the PVDF film by silk-screening with a conductive ink, for example silver ink, or by metallisation by vapour deposition or sputtering.
  • the present invention in its broadest aspect is based on the discovery that useful devices can be realised without electrodes or conductors contacting the piezoelectric material.
  • the invention also provides devices making use of this principle.
  • Fig. 1 is a perspective view, partly in section, of a device embodying the invnetion and illustrating the principle thereof;
  • Fig. 2 is a like view of a modified device
  • Fig. 3 is a perspective view, partly broken away, of a further embodiment
  • Fig. 4 is a cross-section of another embodiment; and Fig. 5 is a similar cross-section of yet another embodiment.
  • a transducer comprises a sheet 10 of PVDF film each face of which is covered with an insulating layer 12 of a dielectric material which in turn is covered by a conductive layer 14.
  • a conductive layer 14 When the film 10 is deformed by compression, bending or stretching, electric charge is created within it, which is capacitively voupled to the conductive layers 14 and in turn causes a current to flow via conductors 16 through an external circuit indicated at 18 A convenient means of providing the insluating layers
  • the conductive members 22 are sheets of an electrically conductiv mechanically compliant foam material; one suitable material is ENSOLITE CEC (trade mark) by Uniroyal, which is a vinyl nitrile foam loaded with carbon. Other plastics or rubbers in foam or sheet form and containing dispersed conductive material such as carbon, copper, aluminium, or silver would also be suitable.
  • ENSOLITE CEC has a
  • FIG. 3 illustrates an embodiment for dealing with a situation where it is desired to detect the occurrence and/or the intensity of a force occuring within a relatively large area, but where the location of the force within that area is not of significance.
  • the PVDF sheets 30 it is necessary for the PVDF sheets 30 to be insulated from the conductive sheets 32 and 34; it is also necessary for the cinductive sheets 32 and 34 to be insulated from each other in those areas where no PVDF material is present. This is suitably achieved by coating one side of the PVDF sheets 30 with an insulating adhesive, securing these in position on one of the foam sheets 32, covering the whole surface of the other foam sheet 34 with an insulating adhesive, and adhering this over the first assembly.
  • Conductors 36 attached to the sheets 32, 34 connect the transducer to an external circuit indicated at 38.
  • a force applied to any part of the transducer will produce a signal to the circuit 38representative of the occurrence and magnitude of the force, althought here will of course be no indication of the location of the force on the transducer area.
  • Fig. 4 shows an embodiment in which a number of discrete PVDF films 40 are secured between common conductive sheets 42 and 44, and separated therefrom by non-conductive adhesive layers 46. In this embodiment, however, each PVDF film is provided on its major faces with metallised coverings 48, which may for example be of aluminium.
  • Metalli PVDF film is well known per se and is commercially available The advantage of including a metallised layer of this nature is that charge created within the PVDF material by the application of a force is spread across the metallised surface which provides a larger area for capacitive coupling to the outer conductor 42 or 44.
  • the conductive layers 42, 44 may be metal foil, conductive impregnated cloth, or conductive foam, and the adhesive 46 may conveniently be an epoxy or a double-sided pressure-sensitive tape. Similar materials may also be used in other embodiments.
  • Fig. 5 is concerned with providing a piezoelectric transducer which is transparent, or at least partially transmissive, to light. This obviously requires the use of light transmissive electrodes.
  • Transparent electrodes are well known- in other fields, but difficulties can arise in applying them to PVDF and similar materials.
  • a particular useful material for transparent electrodes is indium-tin oxide (ITO) , but deposition of ITO on a plastic substrate involves the use of temperatures above the transition temperature for PVDF.
  • the transducer of Fig. 5 comprises a PVDF film 50 secured by layers of insulating adhesive 52 between sheets 54 each comprising a transparent layer of ITO 56 deposited on a MYLAR (trade mark) film substrate; methods of metallising MYLAR in this way are well known to those skilled in the art.
  • the invention makes it possible to keep the production of electrodes quite separate from the piezo material.
  • the invention provides other advantages. Large arrays of complex shapes of piezo material can be achieved without complex conductor arrangements. Solder connections may be made to non-piezo electrode sheets before assembling the transducer. The thickness of, and the material constituting, the insulating layers can be selected to provide a desired value of capacitance; this can be used in conjunction with the characteristics of the piezo material itself to produce desired electrical properties for the transducer, for example by altering resonant frequencies.

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Abstract

Un film (10), à base d'un matériau piezoélectrique polymère tel que du fluorure de polyvinylidène, est connecté à un circuit externe (18), sans qu'il soit nécessaire d'utiliser une quelconque connexion conductrice avec le film (10). Des éléments conducteurs (14) sont espacés du film (10) par un matériau diélectrique (12), constitué de préférence par un adhésif qui fixe également lesdits éléments les uns aux autres. Dans des modes de réalisation préférés, les éléments (14) sont mécaniquement déformables, tels qu'une mousse ou un tissu conducteur .
PCT/GB1987/000394 1986-06-07 1987-06-08 Transducteurs piezoelectriques Ceased WO1987007767A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8613881 1986-06-07
GB868613881A GB8613881D0 (en) 1986-06-07 1986-06-07 Piezoelectric transducers

Publications (1)

Publication Number Publication Date
WO1987007767A1 true WO1987007767A1 (fr) 1987-12-17

Family

ID=10599114

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1987/000394 Ceased WO1987007767A1 (fr) 1986-06-07 1987-06-08 Transducteurs piezoelectriques

Country Status (3)

Country Link
AU (1) AU7482287A (fr)
GB (1) GB8613881D0 (fr)
WO (1) WO1987007767A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10359297A1 (de) * 2003-12-17 2005-07-28 Lisa Dräxlmaier GmbH Piezoschalter
CN111902506A (zh) * 2018-03-26 2020-11-06 日东电工株式会社 发泡片

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0034077A2 (fr) * 1980-02-12 1981-08-19 Jacques Lewiner Perfectionnements aux nappes composites constitutives de transducteurs électromécaniques et aux transducteurs équipés de telles nappes
EP0086922A1 (fr) * 1981-12-31 1983-08-31 Thomson-Csf Procédé de fabrication de transducteurs piézo-électriques polymères
EP0174837A2 (fr) * 1984-09-11 1986-03-19 Focas Limited Cable coaxial piézoélectrique à conducteur interne hélicoidal

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0034077A2 (fr) * 1980-02-12 1981-08-19 Jacques Lewiner Perfectionnements aux nappes composites constitutives de transducteurs électromécaniques et aux transducteurs équipés de telles nappes
EP0086922A1 (fr) * 1981-12-31 1983-08-31 Thomson-Csf Procédé de fabrication de transducteurs piézo-électriques polymères
EP0174837A2 (fr) * 1984-09-11 1986-03-19 Focas Limited Cable coaxial piézoélectrique à conducteur interne hélicoidal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10359297A1 (de) * 2003-12-17 2005-07-28 Lisa Dräxlmaier GmbH Piezoschalter
US7564170B2 (en) 2003-12-17 2009-07-21 Lisa Dräxlmaier GmbH Piezoswitch
CN111902506A (zh) * 2018-03-26 2020-11-06 日东电工株式会社 发泡片
US11511511B2 (en) 2018-03-26 2022-11-29 Nitto Denko Corporation Foam sheet

Also Published As

Publication number Publication date
AU7482287A (en) 1988-01-11
GB8613881D0 (en) 1986-07-09

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