CA2034500A1 - Pvdf/trfe piezoelectric transducer - Google Patents
Pvdf/trfe piezoelectric transducerInfo
- Publication number
- CA2034500A1 CA2034500A1 CA002034500A CA2034500A CA2034500A1 CA 2034500 A1 CA2034500 A1 CA 2034500A1 CA 002034500 A CA002034500 A CA 002034500A CA 2034500 A CA2034500 A CA 2034500A CA 2034500 A1 CA2034500 A1 CA 2034500A1
- Authority
- CA
- Canada
- Prior art keywords
- transducer
- dome
- large area
- sheet
- pvdf
- 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.)
- Abandoned
Links
- 229920002981 polyvinylidene fluoride Polymers 0.000 title claims abstract description 15
- 238000007666 vacuum forming Methods 0.000 claims abstract description 7
- 238000001746 injection moulding Methods 0.000 claims abstract description 6
- 229920001577 copolymer Polymers 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 3
- 230000001419 dependent effect Effects 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000012780 transparent material Substances 0.000 claims 1
- 239000002033 PVDF binder Substances 0.000 abstract description 13
- 238000000034 method Methods 0.000 abstract description 3
- MIZLGWKEZAPEFJ-UHFFFAOYSA-N 1,1,2-trifluoroethene Chemical group FC=C(F)F MIZLGWKEZAPEFJ-UHFFFAOYSA-N 0.000 abstract 1
- 239000002861 polymer material Substances 0.000 description 5
- 230000002706 hydrostatic effect Effects 0.000 description 4
- 238000000465 moulding Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- SUBDBMMJDZJVOS-UHFFFAOYSA-N 5-methoxy-2-{[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl}-1H-benzimidazole Chemical compound N=1C2=CC(OC)=CC=C2NC=1S(=O)CC1=NC=C(C)C(OC)=C1C SUBDBMMJDZJVOS-UHFFFAOYSA-N 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920000131 polyvinylidene Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0688—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction with foil-type piezoelectric elements, e.g. PVDF
-
- 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
- H10N30/09—Forming piezoelectric or electrostrictive materials
- H10N30/098—Forming organic materials
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Transducers For Ultrasonic Waves (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
Abstract
A large area transducer suitable for use in a hydrophone comprises a sheet (6) of polyvinylidene fluoride/trifluoro ethylene formed with a plurality of dome-shaped protrusions (7) which may be formed simultaneously using a vacuum forming an injection moulding technique. The dome-shaped protrusions (7) are closed by a rigid baseplate (8) to enable the transducer to operate in the transverse mode.
Description
wo ~0!13~67 2 ~ 3 ~ ~ o ~ PCT~B90/00661 PVdF/TrFE piezoelectric transducer.
This invention relates to transducers (e.g hydrophone transdueers) and relates more specifically to large area transducers which are required, for examp~e, in large area sonar arrays employed in submarines, for example.
Large area transducers may comprise composite materials with polyvinylidene fluoride (PVdF) sheet as the acti~e element.
Alternatively, polyvinylidene fluorideltrifluoro athylene (PVdF/TrFE) co-polymer materials may be used which has the advan~age that normal polymer moulding techniques, such as vacuum forming and injection moulding can be used before poling of ~he matenal takes place. This is in contrast to the use of PVdF sheet as the active element of the transducer where uniaxial stretching must take place during or prior to poling thereby placin~g severe constraints upon the forms of transducer t~at can be made using PVdF sheet.
The simplest known form of large area hydrophone tran~ducer using PVdF she~ matenal or its co-polymer PVdF/Tr~E comprises a plaîn sheet of PVdF poled through the thiclcness of ~he sheet and arranged to operate in hydrostatic mode~ However? the hydrostatic mode of operation of large area hydrophone transducers inherently, ;
lacks the desired degree of sensitivity and an adequate peaformanee of such hydrophones can only reaIly be achieved by the use of associa~ed high quality elec~ronics equipment.
An aiternative construction of hydrophone transducer which utilises the co-polymer of PVdF comprises a flanged hollow dome WO 90/13367 . PCT/GB9~/00661 2~3~o~ 2 ~
structure formed from the co~ polymer in which the base of the hollow dome struc~ure is c}osed by a rigid base element. The -~
presence of air in the hollow dome structure allows ~he hydrophone transducer to operate in the so-called transversed mode. This trans~erse mode of operation renders the hydrophone transducer inherently more sensitive (e.g. by 20dB) than the hydrostatic mode of operation. The hollow dome structure may be formed by vacuum forming or injection moulding.
The present invention is directed to a relatively low-cost high-performance large area transducer which lcnds itself to high volume produc~ion.
According to the present invention there is provided a large area transducer (e.g. hydrophone transducer) comprising a sheet of PVdF/Tr:E~E formed with a plurality of dome-shaped protrusions ~he bases of which are closed by means of a ri,~id baseplate to provide a plurality of hollow dome structures the number of these dome structures and their size being dependent inter alia upon the requisite deforrnation ~e.g. acoustic) properties of the transducer.
The dome structures may all be of the same size or $he dome sizes may be varied across the sheet of co-polymer material in order to provide a requisite beam pattern.
The dome s~ructures are preferably formed simultaneously in the sheet o~ co-polymer :material by vacuum forming or injection moulding. :
By way of example the present invention will now be described with reference to the accompanying :drawings in which:-Figure 1 shows~ a known single dome transducer struc~ure; and, WO 90/13367 2 Q 3 4 01~ PCr/GB90/00661 Figure 2 shows a multiple dome structure large areahydrophone transducer according to the invention.
Referring to Figure 1, this shows a hydrophone transducer comprising a flanged hollow domed struc~ure 1 formed from a sheet of PVdFtTrFE co-polymer material by vacuum forrning or iniection moulding. The open base end of ~he hollow dome 1 is closed by a means of a rigid baseplate 2 so that the~ presence of air contained within the dome structure 1 enables the hydrophone transducer ~o function in the more sensitive so-called transverse mode in response to the impingement of acoustic waves thereon rather than the!
hydrostatic mode when submerged below the sea surface. Electrodes for $he hydrophone ~ansducer are provided at 3 and 4 and are connected to the ~lange 5 of the dome structure 1 and the backplate 2" respectively.
: .
Referring now to Figure 2 of the drawings, this shows a large area hydrophone transducer according to~ the invention. The transducer comprises a rel~tlvely large sheet of PVdP/TrFE co-polymer material 6 formed, as by vacuum forming, with a plurality of dome-shaped ~protrusions 7 the open ends of which are closed by a common r gid backp!ate 8 which is preferably m~de of acoustically transparent ma~eri~l such as glass reinforced resin. The air trapped within ~the donné structu-es allows the multiple domed hydrophone transducer to operate~ in the more sensitive ~transverse mode ~wh~n submerged below the sea surface~ and havin~g acous~ic waves impinging thereon. ~ The~ transducer Is provided with electrodes ~9 and 10 which are connected, ~respecnvely, to the sheet 6 and the back plate 8.
~ ; : . : :
~ .
This invention relates to transducers (e.g hydrophone transdueers) and relates more specifically to large area transducers which are required, for examp~e, in large area sonar arrays employed in submarines, for example.
Large area transducers may comprise composite materials with polyvinylidene fluoride (PVdF) sheet as the acti~e element.
Alternatively, polyvinylidene fluorideltrifluoro athylene (PVdF/TrFE) co-polymer materials may be used which has the advan~age that normal polymer moulding techniques, such as vacuum forming and injection moulding can be used before poling of ~he matenal takes place. This is in contrast to the use of PVdF sheet as the active element of the transducer where uniaxial stretching must take place during or prior to poling thereby placin~g severe constraints upon the forms of transducer t~at can be made using PVdF sheet.
The simplest known form of large area hydrophone tran~ducer using PVdF she~ matenal or its co-polymer PVdF/Tr~E comprises a plaîn sheet of PVdF poled through the thiclcness of ~he sheet and arranged to operate in hydrostatic mode~ However? the hydrostatic mode of operation of large area hydrophone transducers inherently, ;
lacks the desired degree of sensitivity and an adequate peaformanee of such hydrophones can only reaIly be achieved by the use of associa~ed high quality elec~ronics equipment.
An aiternative construction of hydrophone transducer which utilises the co-polymer of PVdF comprises a flanged hollow dome WO 90/13367 . PCT/GB9~/00661 2~3~o~ 2 ~
structure formed from the co~ polymer in which the base of the hollow dome struc~ure is c}osed by a rigid base element. The -~
presence of air in the hollow dome structure allows ~he hydrophone transducer to operate in the so-called transversed mode. This trans~erse mode of operation renders the hydrophone transducer inherently more sensitive (e.g. by 20dB) than the hydrostatic mode of operation. The hollow dome structure may be formed by vacuum forming or injection moulding.
The present invention is directed to a relatively low-cost high-performance large area transducer which lcnds itself to high volume produc~ion.
According to the present invention there is provided a large area transducer (e.g. hydrophone transducer) comprising a sheet of PVdF/Tr:E~E formed with a plurality of dome-shaped protrusions ~he bases of which are closed by means of a ri,~id baseplate to provide a plurality of hollow dome structures the number of these dome structures and their size being dependent inter alia upon the requisite deforrnation ~e.g. acoustic) properties of the transducer.
The dome structures may all be of the same size or $he dome sizes may be varied across the sheet of co-polymer material in order to provide a requisite beam pattern.
The dome s~ructures are preferably formed simultaneously in the sheet o~ co-polymer :material by vacuum forming or injection moulding. :
By way of example the present invention will now be described with reference to the accompanying :drawings in which:-Figure 1 shows~ a known single dome transducer struc~ure; and, WO 90/13367 2 Q 3 4 01~ PCr/GB90/00661 Figure 2 shows a multiple dome structure large areahydrophone transducer according to the invention.
Referring to Figure 1, this shows a hydrophone transducer comprising a flanged hollow domed struc~ure 1 formed from a sheet of PVdFtTrFE co-polymer material by vacuum forrning or iniection moulding. The open base end of ~he hollow dome 1 is closed by a means of a rigid baseplate 2 so that the~ presence of air contained within the dome structure 1 enables the hydrophone transducer ~o function in the more sensitive so-called transverse mode in response to the impingement of acoustic waves thereon rather than the!
hydrostatic mode when submerged below the sea surface. Electrodes for $he hydrophone ~ansducer are provided at 3 and 4 and are connected to the ~lange 5 of the dome structure 1 and the backplate 2" respectively.
: .
Referring now to Figure 2 of the drawings, this shows a large area hydrophone transducer according to~ the invention. The transducer comprises a rel~tlvely large sheet of PVdP/TrFE co-polymer material 6 formed, as by vacuum forming, with a plurality of dome-shaped ~protrusions 7 the open ends of which are closed by a common r gid backp!ate 8 which is preferably m~de of acoustically transparent ma~eri~l such as glass reinforced resin. The air trapped within ~the donné structu-es allows the multiple domed hydrophone transducer to operate~ in the more sensitive ~transverse mode ~wh~n submerged below the sea surface~ and havin~g acous~ic waves impinging thereon. ~ The~ transducer Is provided with electrodes ~9 and 10 which are connected, ~respecnvely, to the sheet 6 and the back plate 8.
~ ; : . : :
~ .
3~7 ` . PCI/G~90/0066]
~o~500 ~ - `:
The thickness of the sheet 6 and the size of the dome structures will need to take into account the sea pressure to which the transducer will be subjected when submerged. Purely by way of example a co-polymer sheet 1~ cm2 may be provided with about 30 dosne structures but the number of domes will be limited by the vacuum forming process. The alternative use of injection moulding for producing the dome-shaped protrusions simultaneously is also envisaged.
The number of domes needed to provide the requisite acoustic properties will depend upon dome size and the extent of the electroding.
In the manufacture of the transducer shown the dome-shaped protrusions 7 will be formed on the sheet 6 of co-polymer material simultaneously after which the domed sheet and the backplate will be provided with electrodes. Finally, the ~omed sheet will be mounted on the baclcplate 8. It m~y here be mentioned that PVdF
materia~ could not be used for the domed sheet because o~ the need for using uniaxial stre~ching of the material.
Although, in the embodimen~ of Figure 2 the dome protrQsions 7 are all the same size it should be appreciated that the sizes may be varied across the sheet in order ~o produce a desired beam pattern for the transducer.
;~ :
~o~500 ~ - `:
The thickness of the sheet 6 and the size of the dome structures will need to take into account the sea pressure to which the transducer will be subjected when submerged. Purely by way of example a co-polymer sheet 1~ cm2 may be provided with about 30 dosne structures but the number of domes will be limited by the vacuum forming process. The alternative use of injection moulding for producing the dome-shaped protrusions simultaneously is also envisaged.
The number of domes needed to provide the requisite acoustic properties will depend upon dome size and the extent of the electroding.
In the manufacture of the transducer shown the dome-shaped protrusions 7 will be formed on the sheet 6 of co-polymer material simultaneously after which the domed sheet and the backplate will be provided with electrodes. Finally, the ~omed sheet will be mounted on the baclcplate 8. It m~y here be mentioned that PVdF
materia~ could not be used for the domed sheet because o~ the need for using uniaxial stre~ching of the material.
Although, in the embodimen~ of Figure 2 the dome protrQsions 7 are all the same size it should be appreciated that the sizes may be varied across the sheet in order ~o produce a desired beam pattern for the transducer.
;~ :
Claims (7)
1. A large area transducer comprising a sheet of PVdF/TrFE
material formed with a plurality of dome-shaped protrusions and mounted on a rigid base-plate which closes the open ends of the dome-shaped protrusions to provide a plurality of hollow dome structures the number of dome structures provided and their size being dependent inter aria on the requisite deformation (e.g. acoustic) properties of the transducer.
material formed with a plurality of dome-shaped protrusions and mounted on a rigid base-plate which closes the open ends of the dome-shaped protrusions to provide a plurality of hollow dome structures the number of dome structures provided and their size being dependent inter aria on the requisite deformation (e.g. acoustic) properties of the transducer.
2. A large area transducer as claimed in Claim 1, in which the dome structures are all of the same size.
3. A large area transducer as claimed in Claim 1, in which the sizes of the dome structures ale varied across the sheet in order to provide a requisite beam pattern for the transducer.
4. A large area transducer as claimed in any preceding claim, in which the dome-shaped protrusions are formed in the co-polymer sheet by vacuum forming or injection moulding.
5. A large area transducer as claimed in any preceding claim, in which the rigid baseplate is composed of acoustically transparent material such as glass-reinforced resin.
6. A hydrophone embodying a large area transducer as claimed in any preceding claim.
7. A hydrophone transducer substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8910111A GB2233190A (en) | 1989-05-03 | 1989-05-03 | Improvements relating to transducers. |
| GB8910111.7 | 1989-05-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2034500A1 true CA2034500A1 (en) | 1990-11-04 |
Family
ID=10656123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002034500A Abandoned CA2034500A1 (en) | 1989-05-03 | 1990-04-27 | Pvdf/trfe piezoelectric transducer |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0423308A1 (en) |
| AU (1) | AU5562490A (en) |
| CA (1) | CA2034500A1 (en) |
| GB (1) | GB2233190A (en) |
| WO (1) | WO1990013367A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012016378B4 (en) * | 2012-08-13 | 2020-06-18 | Technische Universität Dresden | Dielectric elastomer actuator and process for its manufacture |
| US9772220B1 (en) | 2013-12-06 | 2017-09-26 | Harris Corporation | Hydrophone |
| WO2016130996A1 (en) | 2015-02-13 | 2016-08-18 | Airmar Technology Corporation | Acoustic transducer element |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3816774A (en) * | 1972-01-28 | 1974-06-11 | Victor Company Of Japan | Curved piezoelectric elements |
| NL7508534A (en) * | 1975-07-17 | 1977-01-19 | Philips Nv | Transducer for loudspeakers or microphones - provided with independently acting but adjacently located transducer membrane films |
| GB1593273A (en) * | 1977-09-13 | 1981-07-15 | Standard Telephones Cables Ltd | Electro-acoustic transducers |
| FR2409654B1 (en) * | 1977-11-17 | 1985-10-04 | Thomson Csf | PIEZOELECTRIC TRANSDUCER DEVICE AND MANUFACTURING METHOD THEREOF |
| US4322877A (en) * | 1978-09-20 | 1982-04-06 | Minnesota Mining And Manufacturing Company | Method of making piezoelectric polymeric acoustic transducer |
| US4692285A (en) * | 1985-07-01 | 1987-09-08 | Pennwalt Corporation | Process of preparing nonfibrous, piezoelectric polymer sheet of improved activity |
| US4789971A (en) * | 1986-04-07 | 1988-12-06 | The United States Of America As Represented By The Secretary Of The Navy | Broadband, acoustically transparent, nonresonant PVDF hydrophone |
-
1989
- 1989-05-03 GB GB8910111A patent/GB2233190A/en not_active Withdrawn
-
1990
- 1990-04-27 EP EP90907302A patent/EP0423308A1/en not_active Withdrawn
- 1990-04-27 AU AU55624/90A patent/AU5562490A/en not_active Abandoned
- 1990-04-27 WO PCT/GB1990/000661 patent/WO1990013367A1/en not_active Application Discontinuation
- 1990-04-27 CA CA002034500A patent/CA2034500A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO1990013367A1 (en) | 1990-11-15 |
| EP0423308A1 (en) | 1991-04-24 |
| GB2233190A (en) | 1991-01-02 |
| GB8910111D0 (en) | 1989-11-08 |
| AU5562490A (en) | 1990-11-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |