US3894198A - Electrostatic-piezoelectric transducer - Google Patents

Electrostatic-piezoelectric transducer Download PDF

Info

Publication number
US3894198A
US3894198A US303894A US30389472A US3894198A US 3894198 A US3894198 A US 3894198A US 303894 A US303894 A US 303894A US 30389472 A US30389472 A US 30389472A US 3894198 A US3894198 A US 3894198A
Authority
US
United States
Prior art keywords
oscillator
piezoelectric
electroacoustic transducer
fixed electrode
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.)
Expired - Lifetime
Application number
US303894A
Other languages
English (en)
Inventor
Haohiro Murayama
Takao Oikawa
Kenichi Nakamura
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.)
Kureha Corp
Original Assignee
Kureha Corp
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 Kureha Corp filed Critical Kureha Corp
Application granted granted Critical
Publication of US3894198A publication Critical patent/US3894198A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • H04R17/005—Piezoelectric transducers; Electrostrictive transducers using a piezoelectric polymer
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/01—Electrostatic transducers characterised by the use of electrets
    • H04R19/013—Electrostatic transducers characterised by the use of electrets for loudspeakers
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S310/00—Electrical generator or motor structure
    • Y10S310/80—Piezoelectric polymers, e.g. PVDF

Definitions

  • the present invention relates to an electrostatic type electroacoustic transducer having as the oscillator a piezoelectric polymer showing a piezoelectric effect of developing a stretching motion in the direction perpendicular to the electric axis of the piezoelectric element.
  • FIG. I is a schematic view showing the principle of the conventional piezoelectric type electroacoustic transducers using a piezoelectric polymer as the oscillator.
  • an oscillator film l composed of a piezoelectric substance of a polymer such as a vinylidene fluoride resin having stretching type piezoelectricity has electrodes 2 and 2 at both surfaces thereof. The electrodes are formed by vacuum depositing or attaching a conductor.
  • the stretching type piezoelectric effect referred to above is explained by referring to FIG. 2 of the accompanying drawings. That is, when an electric field is applied to a piezoelectric element A in the direction of the electric axis B of the element, the piezoelectric element A develops an expanding or contracting movement in the direction C perpendicular to the electron axis direction B.
  • the electroacoustic transducer as shown in FIG. I, when a signalfrom an electric system is applied to the electrodes 2 and 2', a stretching motion induced by the aforesaid piezoelectric effect occurs as shown by a dotted line in the FIG. 1, whereby the electroacoustic conversion is effected.
  • the electroacoustic transducer as mentioned above is sufficient for some practical purposes.
  • the piezoelectric film which acts as an oscillator is used in such an electroacoustic transducer.
  • the piezoelectric film is required to show good acoustic characteristics in addition to acting as the oscillator and further it is desirable that the piezoelectric film give a larger sound output so that the electroacoustic transducer can be easily made.
  • the polymer film develops a stretching movement by the application of an electric field to both surfaces of the polymer film, but when the polymer film is stretched in a plane, only the tension of the polymer film changes by the stretching movement and the film does not oscillate. Accordingly, it is required to provide a curvature to the polymer film.
  • the film In order to stretch the polymer film while providing a curvature thereto, the film must be supported. resulting in the oscillations of the film being hindered by the support and the sound thus distorted.
  • the use of a support for a curved film is inevitably accompanied with the problem that the planning and manufacturing of acoustic transducers becomes. in general. complicated.
  • FIG. 3 shows the principle of a cupacitortype electroacoustic transducer using a fixed electret electrode.
  • an oscillator 3 is composed of an oscillator film 4 and an electrode 5 attached thereto and a fixed electret electrode 6 is composed of an electret 7 and a back plate 8 vacuum-deposited or attached thereto.
  • a fixed electret electrode 6 is composed of an electret 7 and a back plate 8 vacuum-deposited or attached thereto.
  • the back plate 8 of the fixed electrode has been connected to the one of the terminals of the secondary winding of a transformer 15, while the electrode 5 of the oscillator has been connected to the other of the terminals of the same secondary winding of the transformer.
  • an ordinary fixed electrode is used in a capacitortype electroacoustic transducer, a dc. bias potential is required but in case of the electret type fixed electrode as mentioned above, the application of a bias potential is unnecessary.
  • an alternating current signal is applied to the primary winding of the transformer 15 through a signal source 16
  • the electrostatic charge on the fixed electrode 6 changes to provide an electrostatic attractive force or an electrostatic repulsive force between the fixed electrode 6 and the oscillator 3, which results in causing the oscillation of the oscillator 3 corresponding to the a.c. potential thus applied.
  • the inventors have investigated techniques for improving the sound output or sensitivity of electroacoustic transducers and as the result it has been discovered that an electroacoustic transducer having excellent characteristics can be obtained by combining the characteristics of a capacitor type electrostatic; electroacoustic transducer and the characteristics of a piezoelectric type electroacoustic transducer.
  • an electroacoustic transducer of the abovementioned electrostaticor capacitor-type is constructed by employing a piezoelectric polymer film, the film having electrodes on both surfaces thereof asthe oscillator film.
  • FIG. 1 the principle was stated that the piezoelectric type electroacoustic transducer using a piezoelectric polymer film as the oscillator are old.
  • the present invention by utilizing the oscillation caused by the piezoelectric polymer film type oscillator and the oscillation caused by the aforesaid capacitor-type electroacoustic transducer in a superposed relationship, larger oscillations have been obtained.
  • the polarity of the piezoelectric polymer film can be determined by the polarity of a dc. electric field applied to the polymer film under heating for providing piezoelectricity to the polymer film. Therefore. it is possible to know quite easily whether a piezoelectric polymer film prepared by the abovementioned method expands or contracts when the piezoelectric polymer film is used as the oscillator film for an electroacoustic transducer and a positive or negative electric field is applied thereto.
  • the oscillation as a capacitor-type electroacoustic transducer due to an a.c. electric field applied to a piezoelectric polymer film employed in the transducer as the oscillator, coincides with the oscillation as a piezoelectric-type electroacoustic transducer. a quite large or strong oscillation can be obtained.
  • FIG. 1 is a prior art piezoelectric transducer.
  • FIG. 2 illustrates the operation of the piezoelectric transducer shown in FIG. 1.
  • FIG. 3 is a prior art electrostatic transducer.
  • FIGS. 4, 4A and 4B show an electrostatic type electroacoustic transducer in accordance with the present invention.
  • FIG. 5 shows another embodiment of an electrostatic type electroacoustic transducer in accordance with the present invention.
  • FIGS. 6 and 7 show the equivalent electrical circuits of the embodiments in FIGS. 4A and B and FIG. 5.
  • FIG. 8 shows another embodiment of an electrostatic type electroacoustic transducer in accordance with the present invention.
  • FIG. 4 shows this transducer in a stationary unexcited state prior to the vibrating operation shown in FIGS. 4A and 4B and prior to supplying the electrical connections among the electrodes and the ac. input.
  • a fixed electrode 9 of the electroacoustic transducer of this invention which is in an ac signal free state, is disposed facing an oscillator 12 consisting of an oscillator film 14 sandwiched between electrodes 13.
  • the surface of the fixed electrode has been charged positively, while the surface of the oscillator 12 has been charged negatively in the state shown in the figure.
  • the fixed electrode 9 is composed of an electret l0 and a back plate 11. If a bias electric source is used, the fixed electrode 9 may be composed of only a conductive plate without an electret.
  • the oscillator 12 has been charged negatively as mentioned above by the polarization potential on the electret 10 and thus the oscillator 12 has been deformed to the side of the fixed electrode by the attractive force caused by the static charges on the electret 10.
  • the oscillator film 14 is made of a piezoelectric polymer film. the oscillator film itself oscillates by the piezoelectric effect in proportion to the change of the electrostatic charges.
  • the oscillator 12 when a positive potential is. for example. applied to the fixed electrode 9 as a signal. the oscillator 12, again comprising the film 14 sandwiched between electrodes 13, approaches the position shown by the dotted lines according to the principle of the electrostatic electroacoustic transducer mentioned above corresponding to a half period of the alternating current signal thus applied. Further if the polarity of the piezoelectric polymer film I4 is so selected that the oscillator expands by the increase of the negative charges on the oscillator on the side near the fixed electrode. the oscillator 12 further approaches the fixed electrode side and the deformation of the oscillator is further increased to the position shown by the solid lines as shown in FIG. 4B.
  • the oscillator 12 moves to a largely deformed position opposite to the above by the repulsive force of the fixed electrode and the reduction of the curvature of the oscillator by the contraction of the piezoelectric polymer film 14. Accordingly, for effectively utilizing the change of the curvature by a contraction of the pi ezoelectric polymer film, the oscillator may be provided with some curvature even in its contracted state.
  • the electrode 9 and one oscillator electrode 13 are to be connected to one side of the secondary winding of transformer I5, whereas the other oscillator electrode I3 is to be connected to the other terminal of the secondary winding.
  • a dc. bias voltage may be applied to the oscillator, as in a general electrostatic type transducer, or an electret is disposed near the oscillator and the electric field thereof may be utilized.
  • the latter system of using the electret is particularly convenient since this requires no transformer having an intermediate tap for increasing the voltages for the polarization potential and the input signal and at the same time dividing them to give opposite charges to both fixed electrodes disposed on opposite sides of the oscillator.
  • an oscillator 12 in FIG. 5 is composed of a piezoelectric polymer film and electrodes vacuum-coated or attached to both surfaces thereof.
  • Two fixed electrodes 9 and 9 each comprise an electret and an electrode disposed at the opposite sides of the oscillator 12, with a proper interval and the fixed electrodes are connected across the terminals of the secondary winding ofa transformer 15.
  • the electrodes of the oscillator 12 are also connected across the secondary winding of the transformer.
  • a signal source 16 has been connected to the primary winding of the transformer IS.
  • the electrets of the fixed electrodes 9 and 9' have been charged preliminarily as indicated in FIG. 5 and when a signal is applied to the fixed electrodes from the signal source 16, the charge on the surface of one of the electrets is cancelled, while the charge on the other is increased.
  • the oscillator causes oscillation. Furthermore, the oscillator develops a bending or bowing movement by the piezoelectric effect due to the change in electrostatic charge and by superposing the oscillation caused by the bending movement. a large oscillation can be obtained from the transducer system.
  • the oscillator film itself may be fabricated in the shape matching such a purpose.
  • the oscillator film may be provided with a curvature or the oscillator film may be fixed locally at at least one position by a fixing substance at, for instance, a central portion thereof.
  • the piezoelectric polymer used in this invention may be a piezoelectric element made of a vinylidene fluoride resin showing large piezoelectricity.
  • vinylidene fluoride resin in this specification refers to polyvinylidene fluoride or a copolymer of vinylidene fluoride and at least one monomer copolymerizable with vinylidene fluoride.
  • a non-oriented film of the vinylidene fluoride resin which was subjected to do. electric field or a nonoriented film of the vinylidene fluoride resin which was, after being uniaxially oriented subjected to a dc. electric field under heating shows a high piezoelectricity and it can be used in the electroacoustic transducer of this invention.
  • the piezoelectric constant becomes higher than c. g. s. e. s. u. Furthermore, even if the heating temperature is comparatively low, a piezoelectric substance having a high piezoelectricity can be obtained by increasing the electric potential applied thereto.
  • a piezoelectric polymer prepared from the non-oriented film of the vinylidene fluoride resin does not have a particularly high piezoelectricity but has the advantage that the polymer is isotropic.
  • a piezoelectric polymer prepared from an oriented vinylidene fluoride resin film is anisotropic, the polymer can be provided with a quite high piezoelectricity.
  • a piezoelectric polymer film having a piezoelectric constant of about 10 c. g. s. e. s. u. can be produced.
  • a electric field of more than 100 kv/cm. at temperatures between 40C. and 180C a practically applicable piezoelectric film of the vinylidene fluoride resin can be prepared.
  • a piezoelectric polymer film showing a high stretching type piezoelectricity can be obtained and can be used in the electroacoustic transducer of this invention.
  • Thin small massed piezoelectric polymer films are preferable for use as a vibrator and a thin film of 2p. to 200p. in thickness is generally used. Furthermore, the gap between the piezoelectric vibrator and fixed electrode in this invention as well as condenser-type microphones is usually in a range from p. to 3 cm. It may be designed by considering only an input voltage in the case of speakers, and by considering an input acoustic wave, amplitude of vibration film, mass of vibrator, etc., for microphones.
  • the electroacoustic transducer of this invention has an excellent advantage in that the shape thereof may be desirably selected and further the acoustic characteristics such as frequency characteristics. directivity, etc.,
  • the thickness of the device can be greatly reduced. Further, when it is utilized as headphones, the weight of the device can also be reduced.
  • the equivalent circuits of the electroacoustic transducers shown in FIG. 4 and FIG. 5 are those shown in FIG. 6 and FlG. 7 respectively, that is, the circuit in which two or three capacitors have been connected in parallel. Because the deformation due to the electrostatic force is superposed by the deformation due to the piezoelectric effect, and because the capacitors are connected in parallel as stated above by referring to the equivalent circuit, the piezoelectric sensitivity of the transducer of this invention is considerably higher. Thus, it is possible to omit the transformer or reduce the winding ratio of the transformer, which makes it possible to minimize the size of the impedance transducer and to provide an electroacoustic transducer having a good S/N ratio at a low cost. Furthermore, because a transducer having a large electrostatic capacity is obtained, the influence of the distribution capacity of lead wires can be substantially reduced.
  • the sound output from the electroacoustic transducer of this invention is sufficient for practical uses.
  • the structure of the electroacoustic transducer of this invention is quite simple, the transducer can be produced easily and further the electroacoustic transducer having excellent acoustic characteristics can be produced with low cost.
  • the electroacoustic transducers of this invention can be utilized for headphones, speakers, microphones, pickups, etc.
  • the surface of the piezoelectric polymer film which had faced a positive electrode at the provision of the piezoelectricity is charged negatively.
  • the piezoelectric polymer film is contracted, the surface thereof is charged positively.
  • the polymer film contracts, while when a positive potential is applied, the polymer film expands.
  • the electroacoustic transducer has a structure that the surface, of the polyvinylidene fluoride resin filmwhich had faced a positive electrode at the application of d.c. electric field for providing the piezoelectricity to the polymer film, faces, as the oscillator, the surface of an electret having positive potential.
  • An embodiment where the piezoelectric element is always exposed to the electric field opposite to the electric field applied at the provision of the piezoelectricity to the polymer film, is preferable when the oscillator takes a large displacement or a large bending movement for, e.g., low frequency purposes, because the oscillator film is not brought into contact with the electrode even if the amplitude of the bending movement becomes larger; however, there is a fear that the internal polarization of the piezoelectric film might be destroyed to reduce the piezoelectricity. Therefore.
  • the direction of the electric field of the electret be same as the direction of the electric field applied in the case of providing the piezoelectricity to the piezoelectric polymer film.
  • the polymer film for the piezoelectric element used in this example was prepared by extruding a powder of polyvinylidene fluoride produced by suspension polymerization through an extruder into a film of 100 microns in thickness and then stretching the film by a factor of four at 100C. to provide a polymer film of 25 microns in thickness.
  • the film was placed between two electrodes and one of the electrodes was, at the positive side, connected to a high voltage generator, while the other electrode was grounded.
  • a dc. electric field of 1000 kv/cm was applied to the electrodes at a temperature of 90C. and the polymer film was cooled to room temperature in that condition to provide a piezoelectric film to be used as the oscillator.
  • a sheet ofa composition of 70% by weight polyvinylidene fluoride and 30% by weight polymethyl methacylate having a diameter of 10 cm and a thickness of 1.0 mm. was placed between two electrodes and after applying a dc. electric field of 100 kv/cm. at a temperature of 90C. for 30 minutes, the polymer sheet was cooled to room temperature in that condition to provide an electret showing an electric field strength of 3000 volts/cm, which was used as the fixed electrode.
  • the electret 10 prepared as above. has a back aluminum plate 11 vacuum coated thereon and is disposed as an oscillator facing the oscillator 12 prepared as above.
  • the two elements are covered by protective plates 17 and 18, the protective plate 18 having perforations l9.
  • the protective plates and the elements are separated from each other by means of annular spacers 20, 21 and 22 and the oscillator 12 is supported by means of a packing 23.
  • the interval between the oscillator and the fixed electrode is 1 mm.
  • An electrostatic type electroacoustic transducer comprising:
  • a. oscillator means fixed at two portions thereof and including a piezoelectric polymer sheet having stretching-type piezoelectric characteristics and electrodes on both surfaces of said polymer sheet;

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Headphones And Earphones (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
US303894A 1971-11-04 1972-11-06 Electrostatic-piezoelectric transducer Expired - Lifetime US3894198A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46087854A JPS5221364B2 (pl) 1971-11-04 1971-11-04

Publications (1)

Publication Number Publication Date
US3894198A true US3894198A (en) 1975-07-08

Family

ID=13926458

Family Applications (1)

Application Number Title Priority Date Filing Date
US303894A Expired - Lifetime US3894198A (en) 1971-11-04 1972-11-06 Electrostatic-piezoelectric transducer

Country Status (6)

Country Link
US (1) US3894198A (pl)
JP (1) JPS5221364B2 (pl)
CA (1) CA989972A (pl)
FR (1) FR2158571B1 (pl)
GB (1) GB1405789A (pl)
NL (1) NL7214888A (pl)

Cited By (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970862A (en) * 1974-06-25 1976-07-20 The United States Of America As Represented By The Secretary Of The Navy Polymeric sensor of vibration and dynamic pressure
US3973150A (en) * 1974-02-18 1976-08-03 Pioneer Electronic Corporation Rectangular, oriented polymer, piezoelectric diaphragm
US3980838A (en) * 1974-02-20 1976-09-14 Tokyo Shibaura Electric Co., Ltd. Plural electret electroacoustic transducer
US4064375A (en) * 1975-08-11 1977-12-20 The Rank Organisation Limited Vacuum stressed polymer film piezoelectric transducer
US4093884A (en) * 1972-09-08 1978-06-06 Agence Nationale De Valorisation De La Recherche (Anvar) Thin structures having a piezoelectric effect, devices equipped with such structures and in their methods of manufacture
US4146800A (en) * 1975-10-08 1979-03-27 Gregory Stephen E Apparatus and method of generating electricity from wind energy
US4207442A (en) * 1978-05-15 1980-06-10 Freeman Miller L Driver circuit for electrostatic transducers
US4331840A (en) * 1980-02-22 1982-05-25 Lectret S.A. Electret transducer with tapered acoustic chamber
US4389445A (en) * 1978-07-10 1983-06-21 Kureha Kagaku Kogyo Kabushiki Kaisha Data recording sheet
US4440027A (en) * 1982-05-26 1984-04-03 Ford Motor Company Velocity and mass air flow sensor
US4618796A (en) * 1984-10-12 1986-10-21 Richard Wolf Gmbh Acoustic diode
US4868447A (en) * 1987-09-11 1989-09-19 Cornell Research Foundation, Inc. Piezoelectric polymer laminates for torsional and bending modal control
US4985926A (en) * 1988-02-29 1991-01-15 Motorola, Inc. High impedance piezoelectric transducer
US5558298A (en) * 1994-12-05 1996-09-24 General Electric Company Active noise control of aircraft engine discrete tonal noise
US5949892A (en) * 1995-12-07 1999-09-07 Advanced Micro Devices, Inc. Method of and apparatus for dynamically controlling operating characteristics of a microphone
US6140740A (en) * 1997-12-30 2000-10-31 Remon Medical Technologies, Ltd. Piezoelectric transducer
US20020080984A1 (en) * 2000-07-13 2002-06-27 Amercian Technology Corporation Electrostatic loudspeaker with a distributed filter
US20030099371A1 (en) * 2001-11-29 2003-05-29 Takashi Ogura Piezoelectric speaker
US20050155430A1 (en) * 2002-02-27 2005-07-21 Hutchins David A. Method of inspecting food stuffs and/or associated packaging
US20060149329A1 (en) * 2004-11-24 2006-07-06 Abraham Penner Implantable medical device with integrated acoustic
US20070049977A1 (en) * 2005-08-26 2007-03-01 Cardiac Pacemakers, Inc. Broadband acoustic sensor for an implantable medical device
US20070154035A1 (en) * 2005-10-05 2007-07-05 Seiko Epson Corporation Electrostatic ultrasonic transducer, ultrasonic speaker, sound signal reproducing method, ultra directional acoustic system and display device
US7289638B2 (en) * 2001-02-20 2007-10-30 Akg Acoustics Gmbh Electroacoustic microphone
US20080021289A1 (en) * 2005-08-26 2008-01-24 Cardiac Pacemakers, Inc. Acoustic communication transducer in implantable medical device header
US20080021510A1 (en) * 2006-07-21 2008-01-24 Cardiac Pacemakers, Inc. Resonant structures for implantable devices
US20080021509A1 (en) * 2006-07-21 2008-01-24 Cardiac Pacemakers, Inc. Ultrasonic transducer for a metallic cavity implated medical device
US20080212807A1 (en) * 2005-06-08 2008-09-04 General Mems Corporation Micromachined Acoustic Transducers
US20080312720A1 (en) * 2007-06-14 2008-12-18 Tran Binh C Multi-element acoustic recharging system
US7522962B1 (en) 2004-12-03 2009-04-21 Remon Medical Technologies, Ltd Implantable medical device with integrated acoustic transducer
US20090201623A1 (en) * 2005-05-02 2009-08-13 Nxp B.V. Capacitive rf-mems device with integrated decoupling capacitor
US20100103115A1 (en) * 2008-10-24 2010-04-29 Sony Ericsson Mobile Communications Ab Display arrangement and electronic device
CN101754078A (zh) * 2008-12-12 2010-06-23 志丰电子股份有限公司 驻极体背极式双振膜电声致动器及其制法
US20110033079A1 (en) * 2009-08-10 2011-02-10 Industrial Technology Research Institute Flat loudspeaker structure
US7948148B2 (en) 1997-12-30 2011-05-24 Remon Medical Technologies Ltd. Piezoelectric transducer
US20120099746A1 (en) * 2010-03-29 2012-04-26 Akiko Fujise Piezoelectric acoustic transducer
US20120163638A1 (en) * 2010-12-27 2012-06-28 Murata Manufacturing Co., Ltd. Piezoelectric Sound Component
CN102651836A (zh) * 2011-02-28 2012-08-29 千如电机工业股份有限公司 用于平板型电声致动器的音讯驱动器
EP2512029A1 (en) * 2011-04-11 2012-10-17 ABC Taiwan Electronics Corp. Audio signal driver for flat sound generator
US8825161B1 (en) 2007-05-17 2014-09-02 Cardiac Pacemakers, Inc. Acoustic transducer for an implantable medical device
DE102013222231A1 (de) * 2013-10-31 2015-04-30 Sennheiser Electronic Gmbh & Co. Kg Hörer
CN104813494A (zh) * 2012-11-29 2015-07-29 罗伯特·博世有限公司 具有至少一个第一类型的电极、第二类型的电极和至少一个铁电驻极体的转换器
US20160164433A1 (en) * 2014-12-04 2016-06-09 Samsung Display Co., Ltd. Piezoelectric element including mesoporous piezoelectric thin film
US20170064459A1 (en) * 2015-08-28 2017-03-02 Hyundai Motor Company Detachable microphone and method of manufacturing the same
CN106484096A (zh) * 2015-08-25 2017-03-08 意美森公司 平行板致动器

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50117412A (pl) * 1974-02-18 1975-09-13
JPS5215972B2 (pl) * 1974-02-28 1977-05-06
JPS51101927U (pl) * 1975-02-14 1976-08-16
JPS5215319A (en) * 1975-07-25 1977-02-04 Matsushita Electric Ind Co Ltd Electric sound convertor
US4170185A (en) * 1978-01-09 1979-10-09 Lectret S.A. Preventing marine fouling
GB2079054B (en) * 1980-06-30 1984-02-22 Tokyo Shibaura Electric Co Electret device
JP6278619B2 (ja) * 2013-06-14 2018-02-14 古河電気工業株式会社 振動発電体

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1889748A (en) * 1928-09-07 1932-12-06 Siemens Ag Loud speaker with actuating systems of different types
US2478223A (en) * 1946-03-01 1949-08-09 Clarkstan Corp Electrostrictive translator
US3646413A (en) * 1970-09-25 1972-02-29 Avco Corp Piezoelectric-driven variable capacitor
US3646280A (en) * 1969-08-28 1972-02-29 Pioneer Electronic Corp Backplate for electret loudspeaker

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1889748A (en) * 1928-09-07 1932-12-06 Siemens Ag Loud speaker with actuating systems of different types
US2478223A (en) * 1946-03-01 1949-08-09 Clarkstan Corp Electrostrictive translator
US3646280A (en) * 1969-08-28 1972-02-29 Pioneer Electronic Corp Backplate for electret loudspeaker
US3646413A (en) * 1970-09-25 1972-02-29 Avco Corp Piezoelectric-driven variable capacitor

Cited By (71)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4093884A (en) * 1972-09-08 1978-06-06 Agence Nationale De Valorisation De La Recherche (Anvar) Thin structures having a piezoelectric effect, devices equipped with such structures and in their methods of manufacture
US3973150A (en) * 1974-02-18 1976-08-03 Pioneer Electronic Corporation Rectangular, oriented polymer, piezoelectric diaphragm
US3980838A (en) * 1974-02-20 1976-09-14 Tokyo Shibaura Electric Co., Ltd. Plural electret electroacoustic transducer
US3970862A (en) * 1974-06-25 1976-07-20 The United States Of America As Represented By The Secretary Of The Navy Polymeric sensor of vibration and dynamic pressure
US4064375A (en) * 1975-08-11 1977-12-20 The Rank Organisation Limited Vacuum stressed polymer film piezoelectric transducer
US4146800A (en) * 1975-10-08 1979-03-27 Gregory Stephen E Apparatus and method of generating electricity from wind energy
US4207442A (en) * 1978-05-15 1980-06-10 Freeman Miller L Driver circuit for electrostatic transducers
US4389445A (en) * 1978-07-10 1983-06-21 Kureha Kagaku Kogyo Kabushiki Kaisha Data recording sheet
US4331840A (en) * 1980-02-22 1982-05-25 Lectret S.A. Electret transducer with tapered acoustic chamber
US4440027A (en) * 1982-05-26 1984-04-03 Ford Motor Company Velocity and mass air flow sensor
US4618796A (en) * 1984-10-12 1986-10-21 Richard Wolf Gmbh Acoustic diode
US4868447A (en) * 1987-09-11 1989-09-19 Cornell Research Foundation, Inc. Piezoelectric polymer laminates for torsional and bending modal control
US4985926A (en) * 1988-02-29 1991-01-15 Motorola, Inc. High impedance piezoelectric transducer
US5558298A (en) * 1994-12-05 1996-09-24 General Electric Company Active noise control of aircraft engine discrete tonal noise
US5949892A (en) * 1995-12-07 1999-09-07 Advanced Micro Devices, Inc. Method of and apparatus for dynamically controlling operating characteristics of a microphone
US8647328B2 (en) 1997-12-30 2014-02-11 Remon Medical Technologies, Ltd. Reflected acoustic wave modulation
US6140740A (en) * 1997-12-30 2000-10-31 Remon Medical Technologies, Ltd. Piezoelectric transducer
US7948148B2 (en) 1997-12-30 2011-05-24 Remon Medical Technologies Ltd. Piezoelectric transducer
US8277441B2 (en) 1997-12-30 2012-10-02 Remon Medical Technologies, Ltd. Piezoelectric transducer
US20020080984A1 (en) * 2000-07-13 2002-06-27 Amercian Technology Corporation Electrostatic loudspeaker with a distributed filter
US6760455B2 (en) * 2000-07-13 2004-07-06 American Technology Corporation Electrostatic loudspeaker with a distributed filter
US7289638B2 (en) * 2001-02-20 2007-10-30 Akg Acoustics Gmbh Electroacoustic microphone
US20030099371A1 (en) * 2001-11-29 2003-05-29 Takashi Ogura Piezoelectric speaker
US6978032B2 (en) * 2001-11-29 2005-12-20 Matsushita Electric Industrial Co., Ltd. Piezoelectric speaker
US20050155430A1 (en) * 2002-02-27 2005-07-21 Hutchins David A. Method of inspecting food stuffs and/or associated packaging
US7107852B2 (en) * 2002-02-27 2006-09-19 University Of Warwick Method of inspecting food stuffs and/or associated packaging
US8744580B2 (en) 2004-11-24 2014-06-03 Remon Medical Technologies, Ltd. Implantable medical device with integrated acoustic transducer
US20060149329A1 (en) * 2004-11-24 2006-07-06 Abraham Penner Implantable medical device with integrated acoustic
US20100004718A1 (en) * 2004-11-24 2010-01-07 Remon Medical Technologies, Ltd. Implantable medical device with integrated acoustic transducer
US7580750B2 (en) 2004-11-24 2009-08-25 Remon Medical Technologies, Ltd. Implantable medical device with integrated acoustic transducer
US7522962B1 (en) 2004-12-03 2009-04-21 Remon Medical Technologies, Ltd Implantable medical device with integrated acoustic transducer
US20090201623A1 (en) * 2005-05-02 2009-08-13 Nxp B.V. Capacitive rf-mems device with integrated decoupling capacitor
US8238074B2 (en) * 2005-05-02 2012-08-07 Epcos Ag Capacitive RF-MEMS device with integrated decoupling capacitor
US20080212807A1 (en) * 2005-06-08 2008-09-04 General Mems Corporation Micromachined Acoustic Transducers
US20070049977A1 (en) * 2005-08-26 2007-03-01 Cardiac Pacemakers, Inc. Broadband acoustic sensor for an implantable medical device
US7615012B2 (en) 2005-08-26 2009-11-10 Cardiac Pacemakers, Inc. Broadband acoustic sensor for an implantable medical device
US7570998B2 (en) 2005-08-26 2009-08-04 Cardiac Pacemakers, Inc. Acoustic communication transducer in implantable medical device header
US20080021289A1 (en) * 2005-08-26 2008-01-24 Cardiac Pacemakers, Inc. Acoustic communication transducer in implantable medical device header
US20070154035A1 (en) * 2005-10-05 2007-07-05 Seiko Epson Corporation Electrostatic ultrasonic transducer, ultrasonic speaker, sound signal reproducing method, ultra directional acoustic system and display device
US20080021510A1 (en) * 2006-07-21 2008-01-24 Cardiac Pacemakers, Inc. Resonant structures for implantable devices
US7912548B2 (en) 2006-07-21 2011-03-22 Cardiac Pacemakers, Inc. Resonant structures for implantable devices
US7949396B2 (en) 2006-07-21 2011-05-24 Cardiac Pacemakers, Inc. Ultrasonic transducer for a metallic cavity implated medical device
US8548592B2 (en) 2006-07-21 2013-10-01 Cardiac Pacemakers, Inc. Ultrasonic transducer for a metallic cavity implanted medical device
US20080021509A1 (en) * 2006-07-21 2008-01-24 Cardiac Pacemakers, Inc. Ultrasonic transducer for a metallic cavity implated medical device
US8825161B1 (en) 2007-05-17 2014-09-02 Cardiac Pacemakers, Inc. Acoustic transducer for an implantable medical device
US9731141B2 (en) 2007-06-14 2017-08-15 Cardiac Pacemakers, Inc. Multi-element acoustic recharging system
US20080312720A1 (en) * 2007-06-14 2008-12-18 Tran Binh C Multi-element acoustic recharging system
US7634318B2 (en) 2007-06-14 2009-12-15 Cardiac Pacemakers, Inc. Multi-element acoustic recharging system
US20100049269A1 (en) * 2007-06-14 2010-02-25 Tran Binh C Multi-element acoustic recharging system
US8340778B2 (en) 2007-06-14 2012-12-25 Cardiac Pacemakers, Inc. Multi-element acoustic recharging system
US20100103115A1 (en) * 2008-10-24 2010-04-29 Sony Ericsson Mobile Communications Ab Display arrangement and electronic device
CN101754078A (zh) * 2008-12-12 2010-06-23 志丰电子股份有限公司 驻极体背极式双振膜电声致动器及其制法
US8385586B2 (en) * 2009-08-10 2013-02-26 Industrial Technology Research Institute Flat loudspeaker structure
US20110033079A1 (en) * 2009-08-10 2011-02-10 Industrial Technology Research Institute Flat loudspeaker structure
US8520869B2 (en) * 2010-03-29 2013-08-27 Panasonic Corporation Piezoelectric acoustic transducer
US20120099746A1 (en) * 2010-03-29 2012-04-26 Akiko Fujise Piezoelectric acoustic transducer
US20120163638A1 (en) * 2010-12-27 2012-06-28 Murata Manufacturing Co., Ltd. Piezoelectric Sound Component
US8942393B2 (en) * 2010-12-27 2015-01-27 Murata Manufacturing Co., Ltd. Piezoelectric sound component
CN102651836A (zh) * 2011-02-28 2012-08-29 千如电机工业股份有限公司 用于平板型电声致动器的音讯驱动器
EP2512029A1 (en) * 2011-04-11 2012-10-17 ABC Taiwan Electronics Corp. Audio signal driver for flat sound generator
CN104813494A (zh) * 2012-11-29 2015-07-29 罗伯特·博世有限公司 具有至少一个第一类型的电极、第二类型的电极和至少一个铁电驻极体的转换器
CN104813494B (zh) * 2012-11-29 2018-02-09 罗伯特·博世有限公司 具有至少一个第一类型的电极、第二类型的电极和至少一个铁电驻极体的转换器
WO2015063257A1 (de) 2013-10-31 2015-05-07 Sennheiser Electronic Gmbh & Co. Kg Kopfhörer
DE102013222231A1 (de) * 2013-10-31 2015-04-30 Sennheiser Electronic Gmbh & Co. Kg Hörer
US9900683B2 (en) 2013-10-31 2018-02-20 Sennheiser Electronic Gmbh & Co. Kg Headphones
US20160164433A1 (en) * 2014-12-04 2016-06-09 Samsung Display Co., Ltd. Piezoelectric element including mesoporous piezoelectric thin film
US10937944B2 (en) 2014-12-04 2021-03-02 Samsung Display Co., Ltd. Piezoelectric element including mesoporous piezoelectric thin film
CN106484096A (zh) * 2015-08-25 2017-03-08 意美森公司 平行板致动器
US10488933B2 (en) 2015-08-25 2019-11-26 Immersion Corporation Parallel plate actuator
US20170064459A1 (en) * 2015-08-28 2017-03-02 Hyundai Motor Company Detachable microphone and method of manufacturing the same
US10057690B2 (en) * 2015-08-28 2018-08-21 Hyundai Motor Company Detachable microphone and method of manufacturing the same

Also Published As

Publication number Publication date
JPS5221364B2 (pl) 1977-06-10
CA989972A (en) 1976-05-25
GB1405789A (en) 1975-09-10
NL7214888A (pl) 1973-05-08
DE2253721B2 (de) 1976-02-12
FR2158571A1 (pl) 1973-06-15
DE2253721A1 (de) 1973-05-24
JPS4853713A (pl) 1973-07-28
FR2158571B1 (pl) 1978-11-03

Similar Documents

Publication Publication Date Title
US3894198A (en) Electrostatic-piezoelectric transducer
US3792204A (en) Acoustic transducer using a piezoelectric polyvinylidene fluoride resin film as the oscillator
US3118022A (en) Electroacoustic transducer
US3544733A (en) Electrostatic acoustic transducer
US3942029A (en) Electrostatic transducer
US3787642A (en) Electrostatic transducer having resilient electrode
US4127749A (en) Microphone capable of cancelling mechanical generated noise
US3832580A (en) High molecular weight, thin film piezoelectric transducers
US3798473A (en) Polymer type electroacoustic transducer element
US4186323A (en) Piezoelectric high polymer, multilayer electro-acoustic transducers
US4246448A (en) Electromechanical transducer
US4638206A (en) Sheet-like piezoelectric element
US3858307A (en) Electrostatic transducer
US4228327A (en) Electromagnetic type acoustic transducers
US2105010A (en) Piezoelectric device
US3894199A (en) Electret electrostatic electroacoustic transducer
US5335286A (en) Electret assembly
US3980838A (en) Plural electret electroacoustic transducer
US3663768A (en) Electret transducer
US5142510A (en) Acoustic transducer and method of making the same
US3894333A (en) Electromechanical transducer and method of making same
KR20010108129A (ko) 합성 전해 스피커 어셈블리
US2911484A (en) Electro-acoustic transducer
JPH0378040B2 (pl)
JP3202169B2 (ja) 圧電発音体