Nothing Special   »   [go: up one dir, main page]

WO2001067663A2 - Transducteur audio polymerique bi-stratifie dual - Google Patents

Transducteur audio polymerique bi-stratifie dual Download PDF

Info

Publication number
WO2001067663A2
WO2001067663A2 PCT/US2001/006925 US0106925W WO0167663A2 WO 2001067663 A2 WO2001067663 A2 WO 2001067663A2 US 0106925 W US0106925 W US 0106925W WO 0167663 A2 WO0167663 A2 WO 0167663A2
Authority
WO
WIPO (PCT)
Prior art keywords
laminate
laminate members
pair
members
pairs
Prior art date
Application number
PCT/US2001/006925
Other languages
English (en)
Other versions
WO2001067663A3 (fr
Inventor
Robert D. Corsaro
Original Assignee
The Government Of The United States As Represented By The Secretary Of The Navy
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
Priority claimed from US09/684,978 external-priority patent/US6349141B1/en
Application filed by The Government Of The United States As Represented By The Secretary Of The Navy filed Critical The Government Of The United States As Represented By The Secretary Of The Navy
Priority to AU2001240037A priority Critical patent/AU2001240037A1/en
Publication of WO2001067663A2 publication Critical patent/WO2001067663A2/fr
Publication of WO2001067663A3 publication Critical patent/WO2001067663A3/fr

Links

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

Definitions

  • the present invention relates to loudspeaker sometimes referred to as sound generators. More particularly, the present invention relates to a very low- mass, light-weight sound generator with a wide frequency bandwidth principally used in large surface area applications, such as wall covers, where mass is of crucial importance and when so used in such an arrangement is capable of delivering high sound levels required for audio generation or active sound control.
  • PVDF film or any piezoelectric material
  • thickness change is typically very small, but the length change can be significant.
  • This elongation can be amplified by constructing a bi-laminar pair, often called a "bimorph,” which may be further described with reference to Fig. 1 showing a prior art parallel-laminate configuration 10.
  • Fig. 1 shows two layers 12 and 14 of PVDF film which are glued together with their polarities in the same direction in a manner known in the art.
  • the voltage, ⁇ v, to each PVDF film is applied between the center electrode (CE) (at the laminate interface) and the outer electrode (OE) of each laminate in a manner known in the art.
  • Fig. 1 further illustrates each laminate as having an elongate length L a , and a possible displacement y, whereas the combined thickness of the laminates, along with their associated electrodes is given by t.
  • t is the film thickness (of one layer, such as 12, of the bi-laminate made up of layers 12 and 14)
  • L a is the unconstrained length
  • W is the width of the parallel-laminate configuration 10
  • ⁇ V is the applied voltage.
  • the parameters Y and d 31 are respectively the Young's modulus and the piezoelectric charge constant, both in the direction of length (the so-called "31" direction of the polymer) . If multiple layer pairs, such as multiple pairs of layers 12 and 14, are used (in fully-bonded arrangements) the force increases by the square of the number of pairs .
  • Another common implementation is the series-laminate configuration (not shown) , in which the polarities of the voltage potentials applied to the two layers, such as layers 12 and 14, are reversed and the positive voltage thereof is applied only across the outer two electrodes.
  • This construction of the series-laminate configuration is simpler to fabricate (since it does not have a center electrode) , but disadvantageously produces only half the deflection per applied volt.
  • bi-laminates such as the parallel-laminate configuration 10 and the series-laminate configuration (not shown), is shown (e.g., Fig. 1) in the cantilever configuration, where one end is clamped and the other is free for movement thereof.
  • An alternative configuration is called the "beam" configuration, known in the art, in which both ends of the associated layers, such as layers 12 and 14, are clamped and the center of the associated layers is free to displace vertically.
  • An additional common configuration uses only one active layer, with the other layer being inactive.
  • an "active" layer is meant to represent that the layer experiences movement and that the layer is comprised of an electro-acoustic material, such as a PVDF film.
  • This one active layer arrangement is often called a "monomorph.” It has reduced performance, but is of a lower cost.
  • bi-laminates have been previously used primarily as actuators for motion control. They have also found some use as sound generators in resonant (narrow bandwidth) alarm applications (typically using hard ceramic piezoelectric material) or for very low-level high-frequency novelty music sources.
  • resonant (narrow bandwidth) alarm applications typically using hard ceramic piezoelectric material
  • very low-level high-frequency novelty music sources typically using hard ceramic piezoelectric material
  • the prior art bi-laminate configurations have not used as broad-band sound generators. Therefore, a need exists in the prior art for bi-laminates that serve as broad-band sound generators .
  • An object of the present invention is to provide for bi-laminate configurations each having the ability to generate associated displacements so as to reproduce high sound levels required for audio generation or active sound control .
  • a further object of the present invention is to provide for various bi-laminates configurations, each of which serves as broad-band sound generators.
  • Another object of the present invention is to provide for bi-laminates that may be arranged into different configurations to provide for relatively large arrays all of which serve as broad-band sound generators .
  • Objects and advantages of the present invention are achieved by a bi-laminated members providing for an acoustic transducer.
  • the acoustic transducer comprises a pair of bi-laminate members each having distal opposite ends. At least one layer of each of the pair of bi- laminate members being of an active electro-acoustic material.
  • Each pair of bi-laminate members has inner and outer surfaces with a first electrode affixed to each outer surface of each pair of bi-laminate members and with a second electrode affixed to each inner surface of each pair of bi-laminate members.
  • Each of the pair of the bi- laminate members extends along an elongated length and each of the pairs is affixed to one another at their respective distal opposite ends along the length.
  • At least one of each of the pair of bi-laminate members has a curved central portion along the elongated length disposed between the distal opposite ends. The curved central portion of the bi-laminate member is displaced from its respective bi-laminate member in a direction transverse to the elongated length and effective so as to permit vibration of the bi-laminate members with respect to one another.
  • Fig. 1 is a prior art bi-laminate configuration used in motion control.
  • Fig. 2 is a schematic of a dual bi-laminate element of the present invention.
  • Fig. 3 is a enlarged front view of the dual bi- laminate element of Fig. 2.
  • Fig. 4 illustrates one embodiment of an array utilizing a bi-laminate element of the present invention.
  • Fig. 5 illustrates a predicted sound pressure level spectrum utilizing a 500 voltage drive signal in the operation of one embodiment of the present invention.
  • Fig. 6 illustrates a response curve of the predicted displacement of a bi-laminate configuration per volt drive .
  • Fig. 7 illustrates a response curve indicative of the displacement of one embodiment of a bi-laminate configuration measured at five different locations thereof.
  • Fig. 8 illustrates a predicted sound pressure level spectrum of another embodiment of the present invention.
  • Fig. 9 illustrates a dense packing arrangement comprising one embodiment of the present invention.
  • Fig. 10 illustrates an etch and cut pattern associated with one embodiment of the present invention.
  • Fig. 11 illustrates a response curve associated with the measured and predicted surface displacement of a bi- laminate configuration of one embodiment of the present invention.
  • Fig. 12 illustrates measured and predicted sound pressure level responses associated with one embodiment of the present invention.
  • Fig. 13 illustrates still another embodiment of a bi- laminate configuration of the present invention.
  • Fig. 14 illustrates a still further embodiment of a bi-laminate configuration of the present invention.
  • Fig. 2 illustrates a acoustic transducer 16 having the parameters of elongated length L a , displacement ⁇ y, a thickness parameter, t, that were already shown in the prior art arrangement of Fig. 1, and that were all previously described with reference to expressions (1), (2), and (3).
  • the thickness dimension, t, of the acoustic transducer 16 is associated with each of the pairs of bi-laminated members 18 and 20. More particularly, the pair 18 of bi-laminated members has a thickness, t, and the pair 20 of bi-laminated members also has a thickness t. Further, each pair 18 and 20 of bi- laminated member has a width, , as shown in Fig. 2.
  • the bi-laminated pair 18 comprises at least one layer 22 formed of an active electro-acoustic material, an electrode 24 fixed to a major portion of the outer surface of the layer 22, an electrode 26 fixed to the inner surface of layer 22, a layer 28 preferably formed of an active electro-acoustic material, and an electrode 30 fixed to a major portion of the inner surface of layer 28.
  • the second bi-laminated pair 20 comprises elements 32, 34, 36, 38, and 40 that are respectively the same as elements 22, 24, 26, 28, and 30 of the first bi-laminated pair 18.
  • the bi-laminated pairs 18 and 22 are preferably fixed to one another at their.distal opposite ends by means of a suitable adhesive 42 and are only attached to each other at their edges 44.
  • Fig. 3 illustrates the acoustic transducer 16 as having dimension lines 48, 50, and 52 which correspond to the x,y, and z axes thereof, with the x axes 48 being parallel to the elongated length L a and the z axes 52 being in a direction transverse to the elongated length L a .
  • the acoustic transducer 16 is arranged so as to be effective to permit vibration of the bi-laminate pairs 18 and 20 with respect to one another.
  • Fig. 3 further illustrates that the electrode 24 of the bi-laminate pair 18 and the electrode 34 of the bi- laminate pair 20 both being connected to a ground potential. Further, Fig. 3 illustrates that the electrode 26 of the bi-laminate pair 18 and the electrode 38 of the bi-laminate pair 20 being connected to a positive voltage potential.
  • Each of the bi-laminate pairs 18 and 20 extends along the elongated length L a and each has a curved, such as a convex central portion, as shown in Fig. 2 and 3, along the elongated length L a .
  • the curved central portion is disposed between the distal opposite ends located at edges 44.
  • each of the bi-laminate pairs 18 and 20 is displaceable from one another along the transverse direction 52.
  • the electrodes 24, 30, 34 and 40 are typically of silver ink, and are preferably disposed as much as possible within the confines of the central portion of the convex bi-laminate pairs 18 and 20. More particularly, it is preferred that the electrodes, in particular, electrodes 30 and 40 not contact the adhesive 42.
  • the acoustic transducer 16 shown in Figs. 2 and 3, and sometimes referred to herein as a bi-laminate bender, provides relatively high displacement ⁇ y values previously discussed with reference to equations (l)-(3).
  • the acoustic transducer 16 is essentially four layers, that is, elements 22, 28, 32 and 36, comprised of an active material (such as PVDF film) and configured as a dual bi- laminate bender.
  • the top and bottom layers 22 and 32, respectively, are poled in one direction while the center two layers 28 and 36 are oppositely poled.
  • the top and bottom layered pairs 18 and 20 are glued together by a suitable adhesive while the layers are arranged on a pre- curved form defining the convex central portion of the pairs 18 and 20.
  • the bi-laminate pairs 18 and 20 are then attached to each other only at the two edges 44 shown in Fig. 2.
  • Fig. 4 illustrates a group 54 of the acoustic transducers 16 of Figs. 2 and 3, but only shown in a general manner.
  • the acoustic transducers 16 are brought together with first and second cover sheets 56 and 58 that cover the bi-laminate pairs 18 and 20 and come into contact with the apex of the central portion of each of the bi-laminate pairs 18 and 20 so as to form glue lines 60.
  • An adhesive 62 is placed along glue lines 60 so as to affix the first and second cover sheets 56 and 58 to the bi-laminate pairs 18 and 20 of each of the acoustic transducers 16 at least near the apex of the central portion of each of the acoustic transducers' 16.
  • cover sheets 56 and 58 reduces the influence in-plane or lateral shrinkage of the active elements of the acoustic transducer 16 and, thus, helps to establish a more uniform piston-type motion of the array 54.
  • the term "piston-type motion" is commonly referred to in the art when describing loud speakers having a movable element, that is, the cone of the loud speaker which serves as the piston-type member. Further, the materials used have flexure modes known in the art which are associated with the operation of the acoustic transducers 16 of the present invention.
  • a predictive model for the geometry of the acoustic transducers 16 of Fig. 4 can be considered as a simple device suspended in air, with sound radiating in both the forward and backward directions. (In applications in which the acoustic transducer 16 or group 54 of acoustic transducers has a backing or is wall mounted, the analysis is similar, and the displacement ⁇ y and performance levels may be as much as doubled) . To a reasonable approximation, the performance of this geometry of the acoustic transducers 16 of the array 54 of Fig. 4, can be predicted using the previous equations (1), (2), and (3) for bi-laminate pairs 18 and 20.
  • the bending element of length L a of equations (1), (2), and (3) now has the value L a /2 and can be imagined as being fixed at the glue line 60 in Fig. 4.
  • the tip displacement generated by each of the acoustic transducer 16 would then be represented as a thickness displacement of the array 54 of Fig. 4.
  • the curvature of the element, such as bi-laminate pairs 18 and 20, is small and does not significantly affect this estimate of L a /2.
  • the first and second cover sheets 56 and 58 are preferably of a polymer.
  • the active polymer bi-laminates of pairs 18 and 20 should be sufficiently stiff in length that the driven displacement/force ( ⁇ y and F respectively) are not lost in bending.
  • this stiffness condition can be met by insuring that the length L a of each of the acoustic transducers 16 is smaller than the first flexural mode in the polymer material of the cover sheets 56 and 58, in a manner known in the art.
  • an approximate requirement is that the wavelength of the flexural mode in the sheets 56 or 58 be much longer than the spacing of the supports (i.e., the distance between glue lines 60).
  • the output of the acoustic transducer 16 that is, its flexure or displacement ⁇ y may be limited by the no-load displacement ⁇ y 0 given by equation 2.
  • the displacement ⁇ y obtained will be related to the force F available through the acceleration:
  • ⁇ is the angular frequency.
  • the total mass to be driven m t is the mass of the PVDF layers making up the acoustic transducer 16, the mass of the cover sheets 56 and 58, and the equivalent mass of the air.
  • the equivalent mass of the air is related to the radiation impedance (known in the art) and is usually insignificant relative to the other mass terms of equation 4.
  • equation 4 may be combined with the previous relationship between displacement and force (equation 1) and then by eliminating force, we find
  • P 0 may be expressed by terms known in the art and given as follows:
  • bi- laminate pairs 18 and 20 dimensions may be considered to be 2cm length and 2.8cm in width, and the bi-laminate pairs 18 and 20 weighing less than one gram.
  • the response of such bi-laminates pairs 18 and 20 may be described with reference to Fig. 5.
  • Fig. 5 illustrates a plot 64 representative of the predicted sound pressure level (SPL) spectrum yielded by the acoustic transducer 16 being driven by the application of a 500 volt applied across its electrodes. From Fig. 5 it should be noted that the levels shown therein are associated with nearfields where the acoustic transducer 16 has a rigid back, such as being mounted on a wall. From Fig. 5, it should be seen that the maximum response of the SPL is near 35Hz (for the arrangement shown in Fig. 4) which represents a tradeoff between the maximum available displacement and force. At frequencies below this maximum (35Hz), the performance is limited by the zero-force displacement, which may be further described with reference to Fig. 6 illustrating a plot 66. As seen in Fig.
  • the plot 66 representative of the predicated displacement per volt drive does not extend beyond about 12Hz. Further, the plot 66 of Fig. 6 represents that those frequencies above this maximum (35Hz) are limited by the available (blocked) force. Not shown in the responses of Figs. 5 and 6, is the influence of flexure of the materials used for the elements of the transducers 16. For the embodiment related to Fig. 4, flexure modes become important above 75Hz. The effects of some flexure modes are expected to be more noticeable in the frequency region just above this 75Hz. Near the higher end of the frequency band (i.e., above 300Hz shown in Figs.
  • the high density of the flexural modes may be expected to cause an effective reduction in the acoustic transducers 16 compliance of its elements, such as the PVDF film preferably comprising layers 22, 28, 32, and 36, and increase the deflection over that shown in Figs. 5 and 6.
  • a prototype unit was fabricated and consisted of three acoustic transducers 16 arranged in a manner similar to that shown in Fig. 4. Each of the acoustic transducers 16 had approximately the dimensions and construction features previously given for those of Fig. 4.
  • the prototype unit carrying the three acoustic transducers 16 was evaluated using a laser Doppler vibrometer (LDV) .
  • LDV laser Doppler vibrometer
  • Fig. 7 illustrates a family of curve 68 comprised of plots 70, 72, 74, 76, and 78, which represent the displacement along five different locations of the array comprised of three acoustic transducers 16. Three of the locations were along the glue lines, such as 66, and the other two locations were the mid-points of the arrangement of the three acoustic transducers 16.
  • Fig. 7 has a X axis given in frequency (Hz) and a Y axis given in displacement ⁇ y (decibels relative to one meter per volt (dB re 1 m/v) ) .
  • the measured results in Fig. 7 generally confirm the principles of the present invention. More particularly, the average displacement level shown in Fig. 7 is approximately -174 dB re: m/volt, or 2000 x 10 "12 /volt. This is 100 times greater than the value reported for PVDF material operating in its thickness-mode (e.g., its piezoelectric d 33 constant) . Thus, the practice of the present invention realizes a factor of 100 in the improvement in the use of the PVDF material. At the lower frequencies, the measured displacement of the acoustic transducer 16 is significantly less than that predicted, but higher at increased frequencies. More particularly, a comparison between Figs. 6 and 7 reveals that the measured displacement shown in Fig.
  • Fig. 7 is as much as 30 dB lower than expected at 100Hz shown in Fig. 6, and nominally 5 dB greater than expected at 1kHz.
  • the observed lower displacement of Fig. 7 at low frequencies is believed to be due to the limitations of my first attempt at fabrication, and improvements in fabrication and glue selection are contemplated to improve the performance of future prototypes utilizing the acoustic transducers 16.
  • the increased performance at high frequencies is believed to be due to the lower structural compliance contributed by a high density of structural modes in the cover sheets 56 and 58.
  • Fig. 8 shows two plots 80 and 82, respectively, represented of the predicted SPL at 10 cm distance from the prototype comprised of three acoustic transducers 16 driven at applied voltages of 10 and 100 volts respectively.
  • the sound output of the relative small prototype unit carrying three acoustic transducers 16 cumulatively weighing less than one gram was tested by electrically connecting the unit to the output of a function generator acting as a source of radiation.
  • a function generator acting as a source of radiation.
  • the sound level was estimated aurally as 20 dB, and appeared reasonably uniform from 2 to 10kHz. Below 1kHz the response became inaudible, which is at least partly due to the reduced sensitivity of human hearing at these low levels and frequencies. This is consistent with the behavior expected from the results shown in Fig . 8.
  • the output was obviously much louder. Unfortunately, this prototype device was damaged before the results at these higher voltages could be quantified by the practice of the present invention.
  • the principal advantage of this unit, carrying three acoustic transducers 16, is its low mass and wide bandwidth. It is demonstrably capable of producing sound.
  • the practice of the present invention permits optimization for sound generation and control applications. With a sufficiently large device area, it is capable of producing high controllable, sound levels that would be particularly useful in enclosed rooms or spaces .
  • a further embodiment of the present invention may be described with reference to Fig. 9.
  • Fig. 9 shows a group of acoustic transducers 84 in a woven-type pattern, wherein bi-laminate members of the acoustic transducers 16 are arranged in an interlaced manner relative to each other. These multi-layered laminates can be used to increase the available force to radiated sound. Further, the acoustic transducers 16 of the array 84 can also be stacked to produce a higher output from the acoustic transducer in the low frequencies (displacement limiting) region. The acoustic transducers 16 can easily be overlapped to reduce the distance between support regions. For example, the linear pattern shown in Fig.
  • Fig. 9 is not limited to a rectangular geometry.
  • the embodiment of Fig. 9 can be extended to a disk-type geometry, wherein the outer rims of two bi-laminate disks are glued together. This arrangement has higher stiffness, and hence is more suitable for use with higher forces generating elements or materials.
  • the acoustic transducers 16 of Fig. 9 or the other embodiments of the present invention need not be fabricated as separate components.
  • a larger pre-formed sheet of curved transducers can be cut or punched to remove material between elements as generally illustrated in Fig. 10.
  • By partially cutting the regions 86 between elements of the transducers 16 reasonably free motion at the edges 44 is achieved while maintaining electrical continuity between the elements.
  • Electrode etching may be used on each laminar layer of the elements comprising the transducers 16 to ensure that shorts do not occur at the cuts or regions 86. This approach simplifies the fabrication process since it avoids attaching separate wires to the electrodes of each of the transducers 16.
  • a second prototype acoustic transducer 16 was fabricated having four layers of 25mm thick Kynar type PVDF copolymer film made available from Material Systems, Inc. Each of the films were 9-12 cm in area and had a silver electrode which was selectively etched to form a desired pattern.
  • the films of the layers were paired and glued together and a curve mold was provided to form the bimorph layers, such as layers 22, 28, or 32 and 36 of Fig. 2.
  • These two bimorph layers, constituting bi-laminate pairs 18 or 20, were then glued to each other as well as to the cover plates 56 and 58.
  • the complete assembly weighed 15gm, or less than lkg/m 2 .
  • the completed assembly was formed to be three elements wide, with each element running the full width, such as the width W shown in Fig. 2.
  • the device was adhered to a table and voltage was applied.
  • the displacement generated was measured by a Scanning Laser Doppler Vibrometer.
  • the average surface displacement was measured and the results are shown in Fig. 11, where the units are decibels relative to one meter per volt.
  • Fig. 11 shows two plots 88 and 90, with 88 representing the measured average surface displacement and 90 representing the predicted average surface displacement . From Fig. 11, it is seen that the measured surface area displacement below 100Hz is relatively uniform and in relatively good agreement with the model prediction. As the frequency increases above 100Hz, both the predicated and the measured data show a progressive decrease in displacement. This is believed to be due to the transition to the region where the displacement is limited by available (blocked) force.
  • Fig. 12 illustrates three plots 92, 94, and 96 representative of the measured, predicted, and simple responses of the present invention.
  • the plot 94 represents the "predicted" values in a nearfield estimate derived from using the radiation impedance appropriate to the projector area, that is, the surface area of the transducer under test.
  • the plot 96 represents the "simple" values corresponding to the expected performance of the transducer under test having a relatively large surface area.
  • the plot 92 of Fig. 12 represents the sound pressure levels that were measured using a calibrated microphone in a distance farfield of the projector, that is, the transducer under test. The conditions used during the testing were 200 volts applied across the transducer and a 50cm separation between the support (glue lines) of the transducer.
  • the sound level produced by the transducer under test was approximately that predicted by surface displacement alone. In general, the produced sound level shown in Fig. 12 is slightly higher than predicted, which was believed to occur due to the low drive impedance needed in regions where there is significant modal behavior of the materials making up the elements of the transducer under test.
  • FIG. 13 illustrates an acoustic transducer 98 having bi-laminate members 100 and 102, both preferably formed of a PVDF film.
  • the bi-laminate member 100 has a convex central portion, whereas the bi-laminate member 102 is relatively flat and lays under the convex bi-laminate member 100.
  • the acoustic transducer 98 illustrates the top 100 and bottom 102 bi-laminate members as being arranged with their polarity in a vertical direction.
  • each of the bi-laminate members 100 and 102 carries both an electrode for the ground connection and an electrode for the positive voltage connection in a manner similar to that described with reference to Fig. 3.
  • the outer electrode surface on each bi-laminate member 100 and 102 is grounded, and a voltage is applied to the inner electrode of the bi- laminate members 100 and 102. The positive voltage thus causes the top layer of length "L" to expand, and the bottom of length "S" to contract.
  • the net effect is an increase and curvature of the top layer and a corresponding increase in the separation between the central portion of the layers 100 and 102, labeled as "T.”
  • the displacement and force, related to the acoustic transducer 98, generating ability is approximately given by the expressions
  • t is the film thickness, such as the thickness of layer 100
  • W is the width
  • Y is the Young's modulus of the material making up the layers 100 and 102.
  • a further embodiment of the present invention may be further described with reference to Fig. 14 illustrating a acoustic transducer 106.
  • the transducer 106 comprises first and second bi-laminate members 100 and 102, described with reference to Fig. 13, that extend along the elongated length L a , such as that shown in Fig. 3.
  • the bi- laminate members 100 are arranged so that the apex of each of their central portion mate with each other as shown in Fig. 14.
  • the bi-laminate members 102 are selected to have a length to provide a flat surface for a back-to-back arrangement of the bi-laminate members 100, as shown in Fig. 14.
  • the opposite distal ends of the bi-laminate members 100 are fixed to the bi-laminate members 102 at glue lines 108 and edges 110 by a suitable adhesive 112 as shown in Fig. 14.
  • the first bi-laminate members 100 have central portions along the elongate length and disposed between their distal ends.
  • the central portions of the bi-laminate members 100 are arranged so as to merge toward each other in a direction transverse to the elongated length and effective to permit vibration of the first and second bi-laminate members 100 and 102 with respect to one another.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Abstract

L'invention concerne divers modes de réalisation ayant trait à des générateurs sonores de faible poids qui comprennent respectivement une large bande de fréquences. Selon certains mode de réalisation, le transducteur acoustique fonctionnant comme un générateur sonore est composé de quatre couches de films en PVDF. Les éléments bi-stratifiés supérieurs et inférieurs sont séparément constitués de façon pré-cintrée pour présenter une géométrie ondulées.
PCT/US2001/006925 2000-03-03 2001-03-05 Transducteur audio polymerique bi-stratifie dual WO2001067663A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001240037A AU2001240037A1 (en) 2000-03-03 2001-03-05 Dual bi-laminate polymer audio transducer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/684,978 2000-03-03
US09/684,978 US6349141B1 (en) 2000-03-03 2000-10-10 Dual bi-laminate polymer audio transducer

Publications (2)

Publication Number Publication Date
WO2001067663A2 true WO2001067663A2 (fr) 2001-09-13
WO2001067663A3 WO2001067663A3 (fr) 2011-12-29

Family

ID=24750281

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/006925 WO2001067663A2 (fr) 2000-03-03 2001-03-05 Transducteur audio polymerique bi-stratifie dual

Country Status (2)

Country Link
AU (1) AU2001240037A1 (fr)
WO (1) WO2001067663A2 (fr)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911484A (en) * 1954-06-28 1959-11-03 Gen Electric Electro-acoustic transducer
JPS4829420A (fr) * 1971-08-20 1973-04-19
US5115472A (en) * 1988-10-07 1992-05-19 Park Kyung T Electroacoustic novelties
US5196755A (en) * 1992-04-27 1993-03-23 Shields F Douglas Piezoelectric panel speaker

Also Published As

Publication number Publication date
WO2001067663A3 (fr) 2011-12-29
AU2001240037A1 (en) 2001-09-17

Similar Documents

Publication Publication Date Title
US6349141B1 (en) Dual bi-laminate polymer audio transducer
US7149318B2 (en) Resonant element transducer
JP3994086B2 (ja) スピーカ
JP2894276B2 (ja) 圧電音響変換器
JP2001524278A (ja) 弾性誘電体ポリマフィルム音波アクチュエータ
JP2002526004A (ja) 電子音響振動板変換器付きパラメトリック・スピーカ
EP3354042B1 (fr) Transducteurs à ultrasons
EP1323330B1 (fr) Haut-parleurs electrostatiques
JP2009272978A (ja) フレキシブルスピーカ
JP3502524B2 (ja) トランスデューサアレイ
JPH07327297A (ja) 圧電スピーカ
EP3105941B1 (fr) Transducteur électrostatique amélioré
JP4899590B2 (ja) 静電型スピーカ
US6612399B1 (en) Lightweight low frequency loudspeaker for active noise control
US4024355A (en) Piezoelectric electro-acoustic transducer with non-uniform backing
WO2001067663A2 (fr) Transducteur audio polymerique bi-stratifie dual
CN116320941A (zh) 一种像素发声单元及其制造方法、数字发声芯片
JP3284724B2 (ja) 圧電型スピーカ
JP2024533610A (ja) 多層トランスデューサ
JP7370039B2 (ja) 音圧－電気信号変換装置及びその変換方法
Ohga et al. Wideband piezoelectric rectangular loudspeakers using a tuck shaped PVDF bimorph
JP4697007B2 (ja) 静電型スピーカ
Sugimoto et al. Efficiency of semicylindrical acoustic transducer from a dielectric elastomer film
JP2008259158A (ja) 静電型スピーカ
EP1604542A1 (fr) Haut-parleur a onde de flexion

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP