CN1433661A - Piezoelectric film sonic emitter - Google Patents
Piezoelectric film sonic emitter Download PDFInfo
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- CN1433661A CN1433661A CN00818838A CN00818838A CN1433661A CN 1433661 A CN1433661 A CN 1433661A CN 00818838 A CN00818838 A CN 00818838A CN 00818838 A CN00818838 A CN 00818838A CN 1433661 A CN1433661 A CN 1433661A
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- 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
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K15/00—Acoustics not otherwise provided for
- G10K15/02—Synthesis of acoustic waves
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
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- 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
- H04R17/10—Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2217/00—Details of magnetostrictive, piezoelectric, or electrostrictive transducers covered by H04R15/00 or H04R17/00 but not provided for in any of their subgroups
- H04R2217/03—Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Mechanical Engineering (AREA)
- Health & Medical Sciences (AREA)
- Audiology, Speech & Language Pathology (AREA)
- General Health & Medical Sciences (AREA)
- Multimedia (AREA)
- Transducers For Ultrasonic Waves (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
A speaker device for emitting subsonic, sonic or ultrasonic compression waves comprising a generally hollow drum, a rigid emitter plate attached to the drum, and a plurality of apertures formed within the plate which are covered by a thin piezoelectric film disposed across the emitter plate. A pressure source is coupled to drum for developing a biasing pressure with respect to the thin film at the apertures to distend the film into an arcuate emitter configuration capable of constricting and extending in response to variations in the applied electrical input at the piezoelectric film to therapy create a compression wave in a surronding environment. Parametric ultrasonic frequency input is supplied to the piezoelectric film to propagate multiple ultrasonic frequencies having a difference component corresponding to the desired subsonic, sonic or ultrasonic frequency range.
Description
Technical field
The present invention relates to compressional wave produces.More particularly, the present invention relates to directly produce compression sound wave and compression ultrasonic wave, and produce a new compression sound wave indirectly or compress hyperacoustic apparatus and method by two hyperacoustic reciprocations of compression, described two compression frequency of ultrasonic differences are corresponding to required new compression sound wave or compression frequency of ultrasonic
Background technology
Attempting not have noise ground, to reproduce the effort of sound a lot.In the related application of sequence number 08/684311, commented the background technology of using the loudspeaker techniques of conventional loud speaker in detail with radiated element, this patent application is contained in this as a reference.The shortcoming of this conventional loud speaker is that the quality owing to dynamic diaphragm or other radiated element produces distortion.Relevant issues result from the distortion that the problem of the mismatch of the radiated element of crossing over low frequency, intermediate frequency and high frequency spectrum-utilize woofer, middle pitch loudspeaker and high pitch loudspeaker partly to solve by combination forms.
The effort that utilizes ultrasonic transducer to reproduce audible sound comprises technology, sound heterodyning, difference frequency interference that is embodied in the parameter loud speaker and the multifrequency modulation that produces other form of new frequency.In theory, the interaction of two ultrasonic waves in air (as nonlinear dielectric) that drops in the audio range by its frequency-splitting produces sound.Ideally, resulting compressional wave can be projected onto in the air as nonlinear dielectric, and can be heard as noise-free sound.Although make in this way, produced the puzzled industry of practical sound more than 100 year commonly.Specifically, also do not develop the basic parameter or the difference frequency loud speaker that can be used in according to the mode of for example conventional speaker system in the general application.
At Aoki, " the Parametric Loudspeaker-Characteristics of Acoustic Field and Suitable Modulation ofCarrier Ultrasound " of Kamadura and Kumamoto,
Electronics and Communications in Japan, Part 3, Vol.74, No.9The concise and to the point developing history of theoretical parameter loudspeaker array was provided in (in March, 1991).Although understand sonorific technology component of differential signal and the theory of disturbing between the supersonic frequency by two, but the actual realization of commercial sonification system obviously is unsuccessful.The loud speaker diameter that attention is made up of 1410 piezoelectric transducers nearly is this defective that still there is prior art in 42 centimetres parameter loudspeaker array assembly.In fact the existing research of all in the parameter sounding field is all based on the use of the ultrasonic transducer of routine, the use of especially two piezoelectric characteristics (bimorf character).
The United States Patent (USP) 5357578 that is presented to Taniishi in October, 1994 has proposed the alternative solution about a difficult problem of developing available Parametric Loudspeaker System.Here, the device of proposition comprises the two supersonic frequencies of emission, thereby produces the transducer of required audio frequency difference signal.But current gel media on transducer face is propagated the dual-frequency ultrasonic wave signal.Medium 20 " as the virtual sound source that produces difference tone 23, the frequency of described difference tone 23 is corresponding to the difference between frequency f 1 and the f2 ", the 4th hurdle, mat woven of fine bamboo strips 54-60 is capable.In other words, this part patent in 1994 is abandoned direct surface from transducer and is produced the difference audio signal aloft, and depends on the non-linear sound that produces of gel media.Strengthened at least actual loudspeaker being used invalid understanding to this unexpected transformation of proposing the use gel media from transducer/air interface to having the ineffectivity of public technology now.
Summary of the invention
An object of the present invention is to send the audible new sound wave that to accept volume indirectly from a certain air section the transducer of routine not being used as under the situation in supersonic frequency source.
Another purpose is by utilizing the film reflector to produce at least one new sound wave or the infrasound with commercial acceptable volume indirectly, described film reflector provides the interference between at least two ultrasonic signals, and described at least two ultrasonic signals have and equal described at least one new sound wave or infrasonic difference frequency.
Another purpose provides a kind of wafer speaker diaphragm that can form before the homogeneous wave in the ultrasonic wave surface of emission of broad.
Another purpose of the present invention provides and a kind ofly can respond electrostimulation, produces compressional wave, but does not need the improved speaker diaphragm of stiffness films structure.
In comprising the loud speaker that is arranged in the piezoelectric membrane on the common issue face with some apertures, realize these purposes.Arrange described aperture, so that send compressional wave from film along parallel axes, thereby before forming homogeneous wave.Film is pulled into arch by the nearly vacuum that produces in the bulging cavity after the reflector vibrating membrane, and crosses aperture maintenance tensioning state.The voltage linear that the piezoelectric membrane response applies expands or shrinks, and changes the curvature of aperture top film whereby, produces compressional wave thereby be very similar to conventional speaker diaphragm.This structure not only makes it possible to produce compressional wave, and owing to adopted vacuum, has eliminated the formation of harmful echo.
In another aspect of this invention, reflector comprises the emission drum that is made of the single reflector diaphragm that is arranged in the some apertures top on the common issue face.But by the malleation that applies from the drum cavity, diaphragm arch in aperture expands in the present embodiment.The voltage that response applies produces the similar sound of vibrating membrane and handles; But, must consider that now echo produces.
Another aspect of the present invention is the thin polymer film that is arranged in the help sealing piezoelectric membrane on the piezoelectric membrane and avoids gas permeation.
In another aspect of this invention, reflector comprises the isolated area of controlling piezoelectric membrane, and a plurality of electrodes that create conditions for a plurality of passages in wave beam control and the piezoelectric membrane.
In conjunction with the accompanying drawings, according to following detailed description, for a person skilled in the art, other purpose of the present invention, feature and possible others will be more obvious.
Description of drawings
Fig. 1 is the front view that rouses transducer according to the emission that principle of the present invention is made.
Fig. 2 is the top view of expression according to the some apertures in the surface of emission of the emission drum transducer of principle manufacturing of the present invention.
Fig. 3 a is the broken section outline drawing of the emission drum transducer and the surface of emission, has represented to be arranged in the film of the aperture top in the surface of emission.
Fig. 3 b is the broken section outline drawing of the emission drum transducer and the surface of emission, has represented to stick to the thin polymer film on the piezoelectric membrane.
Fig. 3 c is the broken section outline drawing of emission drum and expelling plate, has represented the piezoelectric membrane in the expelling plate inboard.
Fig. 3 d is the broken section outline drawing of emission drum and emission thin plate, has represented the piezoelectric membrane in the expelling plate inboard.
Fig. 3 e is emission drum, emission thin plate and at the broken section outline drawing of second anchor clamps of piezoelectric membrane offside.
Fig. 4 is the feature outline drawing when the film that vibrates during tensioning in the some apertures in the surface of emission.
Fig. 5 has represented example of the relation curve of film (piezoelectric membrane) displacement and frequency in the preferred embodiment.Resonance frequency and consequent typical bandwidth have been the figure shows.
Fig. 6 is the broken section outline drawing of the emission drum transducer of the pressurized alternative of emission drum transducer.
Fig. 7 is emission ultrasonic wave fundamental frequency of the present invention and the more specifically realization of carrying the frequency of ultrasound information, and described ultrasonic wave fundamental frequency is carried out heterodyning with the frequency of carrying ultrasound information, thereby produces new audio frequency or infra-acoustic frequency.
Fig. 8 is the alternative of the broken section outline drawing of expression sensing drum transducer and sensitive face, has represented to be arranged in the sense film of the aperture top in the sensitive face.
Fig. 9 is the broken section outline drawing that echo strengthens the reflector of structure range transmission face 1/4 wavelength.
Figure 10 is that bonnet is the broken section outline drawing that the echo of range transmission face 1/4 wavelength strengthens the reflector of structure.
Figure 11 is the top view with surface of emission of rectangular element perforate.
Figure 12 is the top view with surface of emission of obround elements perforate.
Figure 13 is the broken section outline drawing of the reflector of the lobed surface of emission.
Figure 14 is the broken section outline drawing with reflector of the spill surface of emission.
Figure 15 is the broken section outline drawing of the lobed surface of emission and the reflector of the backboard of projection, and piezoelectric membrane is in the inboard of the surface of emission.
Figure 16 is the broken section outline drawing with reflector of the spill piezoelectric membrane that is positioned at the expelling plate inboard.
Figure 17 is the top view with surface of emission of two semicircle electric contacts.
Figure 18 is the top view with surface of emission of four electric contacts.
Figure 19 has two top views that electrically contact the surface of emission of ring with one heart.
Figure 20 has three top views that electrically contact the surface of emission of ring with one heart.
Figure 21 represents the polygon part of piezoelectric membrane, and the polygon surface of emission is under this film simultaneously.
Figure 22 represents three polygon parts of piezoelectric membrane, and the corresponding simultaneously surface of emission is under this film.
Figure 23 represents six polygon parts of the hexagon piezoelectric membrane of looping structure.
Figure 24 is four rectangle parts of square piezoelectric membrane.
Figure 25 is four rectangle parts of row shape piezoelectric membrane.
Figure 26 is the compression chamber that links to each other with some piezoelectric membrane transmitter units.
Figure 27 represents to utilize the piezoelectric membrane of PVDC sealing.
Figure 28 is illustrated in the selectivity sputter of the panel aperture top that is connected by the metallization bridging contact.
Embodiment
Traditionally, in the parametric arrays there are a lot of restrictions in PZT (piezoelectric transducer) as speaker element, these restrictions have hindered the many practical applications of transducer in sound wave and ultrasonic wave generation industry.These restrictions comprise that phase place and frequency response are inhomogeneous in the bigger transducer array.Because the minor variations of transducer resonance frequency aspect, and to the variable response of the different frequency in the broadband spectrum, distortion takes place usually, power output reduces and be not intended to Beam Control.Many restrictions in these restrictions result from typical loudspeaker array and are made of a plurality of independent non-homogeneous transducers that are wired to the common signal source respectively.Each transducer is slightly different, and with respect to other transducer parallel or utonomous working in series.
The present invention forms consistency and uniformity by the monofilm piezoelectric is provided in array, described monofilm piezoelectric is predictable to the response of the signal that applies in whole emitter surface.This in a preferred embodiment structure mainly results from reflector and is actually the single film of the same composition that the aperture of crossing over a plurality of same sizes supports.In addition, whole emitter surface combines physically, because thin-film material is arranged on reflector flat board or the disk simply, and is excited by one group of electric contact.So, in fact playing the single film that constitutes by a kind of material by the array of the independent transmitting site of the representative of the corresponding aperture in the reflector flat board, described single film is excited by identical electric input.In the expansion of the arc of each aperture is uniformly, is offset because identical materials is born on identical size from the stretching of the common pressure (malleation or negative pressure) of inside, drum chamber.So make harmonic distortion and phase distortion reduce to minimum, be convenient to cross exercisable frequency bandwidth before the homogeneous wave.
Fig. 1,2,3a and 3b have described the preferred embodiments of the present invention of representing in the broken section view of quadrature.Emission drum transducer (emitter drum transducer) is the cylindrical object of hollow.The sidewall 106 of emission drum transducer 100 is metal or metal alloy.The surface of emission 102 produces compressional wave from the end face of launching bulging transducer 100, and is made up of two assembly-transmitting films 104 and emission flat board or disk 108 at least.
The outer surface of the surface of emission 102 is made of piezoelectric membrane 104.Film 104 is by dull and stereotyped 108 supportings of rigidity emission, and emission dull and stereotyped 108 comprises some apertures 112, and described some apertures 112 can expand in the small arch radiated element film.As mentioned above, these radiated elements in all respects-size, curvature and composition-all identical.This common point causes launching common output in the film surface, likes an independent radiated element well.
In order to understand the structure of emission drum transducer 100 better, Fig. 2 provides the top view of the outer surface 126 that is placed on the independent transmission disk 108 (referring to Fig. 1) below the piezoelectric membrane 104 usually.In a preferred embodiment, disk 108 is metals, and is equipped with measure-alike some apertures 112.Aperture 112 runs through disk 108 fully and arrives outer surface 126 from inner surface 128 (referring to Fig. 3).For predictability and the maximal efficiency that aspect of performance is provided, form aperture 122 with cylindrical shape.
According to a large amount of knowledge that draw about circular dull and stereotyped symmetric curvature, the measurable vibration of piezoelectric membrane 114 when curved tensioning state is suspended on the cylindrical aperture 112.This should not be interpreted as meaning the aperture 112 that can not use other formation.But, preferred embodiment adopts cylindrical aperture 112 as predictable structure.
The pattern of the aperture 112 shown in selecting among Fig. 2 in this case on disk 108 is because this can be provided with the aperture 112 of maximum number in specifying area.This pattern is described to " honeycomb " pattern usually.Because, therefore select honeycomb mode because the characteristic of sound heterodyning preferably has the parallel many apertures 112 of axle.
Especially under the situation that produces supersonic frequency, preferably facilitate fundamental frequency and the heterodyning of carrying between the frequency of information is disturbed, thereby produce new audio frequency or the infra-acoustic frequency of forming by described information.Thereby, make before its interactional a large amount of basic waves and the wavefront of the information of carrying will have usually with independent a pair of fundamental frequency with carry information frequency and compare bigger new audio frequency or the subaudible effect of generation volume.In other words, remarkable advantage of the present invention is to form a large amount of radiated elements that transmit interfering frequency, does not still lose the benefit of public composition, integrated and vibratory response.Obviously, this is to produce a high key factor that arrives the volume aspect of viable commercial.The formation of the acceptable volume level of parallel-oriented further enhancing of frequency emission axle.
Fig. 3 a is the profile and the partial sectional view of the preferred embodiments of the present invention, comprises relating to the more details of rousing the power lug of transducer 100 with emission.The sidewall 106 of emission drum transducer 100 forms the shell of disk 108, and some apertures 112 of disk 108 run through disk 108 simultaneously.Piezoelectric membrane 104 is expressed as contacting with disk 108.Experiment is determined preferably piezoelectric membrane 104 not to be sticked on the whole exposed surface of disk 108, and described piezoelectric membrane 104 contacts with described disk 108.The adhesive tape that size constantly changes between piezoelectric membrane 104 and the aperture 112 causes uniform small pores 112 to produce uneven resonance frequency.So preferred embodiment only pastes the outer rim of piezoelectric membrane 104 on the disk 108.
Another advantage of vacuum has been to eliminate the possibility of undesirable " echo " distortion.The elimination of echo results from and seals the existence of rousing vacuum in the cavity among the present invention.According to definition, need there be its transparent compressible medium in compressional wave.If piezoelectric membrane 104 is produced from launching the ultrasonic compressional wave of bulging transducer 100 along arrow 130 indicated directions " outwards ", then have only equally and produce and to transfer back to emission drum transducer 100 interior ultrasonic compressional waves in opposite direction and to be only logical along by arrow 132 indicated directions from piezoelectric membrane 104.
Lacking under the situation of vacuum condition, these backpropagations or echo distortion ripple can disturb piezoelectric membrane 104 to produce the ability of required frequency.Pass aperture 112 once more and from piezoelectric membrane 104 reflection at echo, thereby change before the vibration of piezoelectric membrane 104, when the surface of echo in launching bulging transducer 100 is reflected, this interference can take place.So,, can eliminate the reflection vibration of piezoelectric membrane 104 by eliminating the propagation medium (air) of compressional wave in the emission drum transducer 100.
Fig. 3 a also represents to exist and piezoelectric membrane 104 electric couplings, and transmits the lead 120 of the electric expression information of the frequency that will send from each unit 124 of launching bulging transducer 100.Thereby as shown in the figure, these leads 120 must be electrically connected with some signal source 122.
Because when emission drum 100 was pressurized, there was pressure leakage in emission drum 100, so importantly taked to prevent the measure of pressure leakage.A kind of method that reduces pressure leakage is to use inert gas to 100 pressurizations of emission drum.For example, the heavy inert gas such as nitrogen, neon or argon can be used for reducing leakage.Inert gas is compared with light gas has bigger molecule, thereby reduces the leakage of spontaneous emission drum 100 or the seepage of piezoelectric membrane 140.
In another embodiment of the present invention, use thin layer polymer-coated piezoelectric membrane.Fig. 3 b has represented to be coated to the polymeric layer 140 on the piezoelectric membrane 104 after polarization is handled.In polarization was handled, piezoelectric membrane was stretched and makes it charged, and this has weakened the gas retention performance of piezoelectric membrane.Polymer coating sealing piezoelectric membrane, thus when emission drum 100 comprised near vacuum, atmosphere can not infiltrate in the emission drum 100.Polymer coating also seals piezoelectric membrane, prevents that the gas that is used for 100 pressurizations of emission drum from spilling.Be important to note that the performance that polymer must be thinned to can not influence piezoelectric membrane.By utilizing so extra one deck thermoplastic coatings,, also can make the pressure in the emission drum 100 more reliable even when using very thin piezoelectric membrane.Will be appreciated that thermoplastic coatings also can be used on the sidewall 106 and bonnet 110 of emission drum, reduces pressure leakage.Sealing piezoelectric membrane or emission drum 100 help to prolong the useful life of reflector.The pressure limit of the reflector shown in the present embodiment is about 0 pound of/square inch (near vacuum)～20 pound/square inch (psi).
Fig. 3 c represents to launch the broken section outline drawing of the drum and the surface of emission.In this structure, piezoelectric membrane is positioned at the inboard of the surface of emission.Inner chamber 142 is pressurized, thereby piezoelectric membrane 104 is pressed into arch as shown in Fig. 4 b.As mentioned above, use polymer coating 140 to help the sealing piezoelectric membrane.The surface of emission 128 shown in this figure is the embodiment with sizable unit depth.Except launching dull and stereotyped 128 thickness significantly the thickness less than emission among Fig. 3 c dull and stereotyped 128, Fig. 3 d represents the embodiment similar with Fig. 3 c.Inner chamber 142 is also pressurized, thereby piezoelectric membrane 104 is pressed into arch as shown in Fig. 4 b.
Fig. 3 e represents to have the partial cut away side views of the emission drum 100 of the surface of emission 128 and second anchor clamps 143.Piezoelectric membrane 104 is clipped between the surface of emission 128 and second anchor clamps 143, and the small structure of described second anchor clamps 143 and the surface of emission 128 conforms to.Piezoelectric membrane 104 is 1/4 wavelength (1/4wL) with the distance of the bonnet 110 of emission drum, makes ripple so that strengthen.When emission drum 100 was pressurized, its produced arch radiated element.In addition, there is the elongate chamber 142 that connects the unit 124 that has small perforate.Will be appreciated that unit 124 also can be attached on the bonnet 110, other place of 124 is provided with perforate in the unit subsequently, so that the pressure in balanced each unit.Second anchor clamps 143 are optional, but it has increased the stability of piezoelectric membrane 104.
Fig. 4 A is the feature outline drawing of two unit (piezoelectric membrane 104 by two aperture 112 tops is formed) of preferred embodiment.Only for illustrational purpose, piezoelectric membrane 104 is shown in the exaggerative vibration, inwardly expand into the inside of emission drum transducer 100.According to the comparison of Fig. 4 B, be outside expansion after the inside expansion of piezoelectric membrane 104 obviously, and leave the inside of emission drum transducer 100, the lax simultaneously signal that applies.Only be for illustrational purpose, represented the swell increment of piezoelectric membrane 104 once more turgidly.Actual swell increment will be discussed in the back.
Fig. 5 represented when with the displacement of piezoelectric membrane 104 (for the function of the voltage RMS that applies) when comparing, the frequency response curve of the emission drum transducer 100 that produces according to the principle of preferred embodiment.The emission drum transducer 100 that provides Fig. 5 is the examples that utilize the typical consequence that the nearly vacuum in emission drum transducer 100 inside obtains.
The film that uses in the present embodiment (piezoelectric membrane 104) is that thickness is about 28 microns polyvinylidene fluoride (PVDF) film.By experiment, prove when using 73.6V
PpDriving voltage the time, the resonance frequency of this particular transmission drum transducer 100 is about 37.23kHz, is about 11.66% with Time Bandwidth, the 6dB frequency is respectively 35.55kHz and 39.89kHz up and down.The maximum displacement double amplitude of finding piezoelectric membrane 104 in addition is also only above about 1 micron.This displacement is corresponding to the sound pressure level of 125.4dB (below be called SPL).
Supposition withstands 1680V to surprisingly so big SPL by utilizing in theory
PpDriving voltage, perhaps be emission drum transducer 100 generations of the PVDF of 22.8 times driving voltage of the driving voltage that applies.Therefore, the theoretical limit of these special materials that use in the emission drum transducer 100 causes wonderful bigger 152.6 SPL.
The resonance frequency of the preferred embodiment shown in importantly remembeing here is the function of the various characteristics of emission drum transducer 100.These characteristics are comprising the thickness and the diameter of launching aperture 112 in the disk 108 of the piezoelectric membrane 104 of tensioning on the surface of emission 102.For example, for the voltage that applies of appointment, utilize thin piezoelectric membrane 104 will cause piezoelectric membrane 104 to vibrate faster.Thereby the resonance frequency of emission drum transducer 100 will be higher.
The advantage of higher resonant frequency is then can easily produce required frequency range if bandwidth percentage keeps being about 10% or increase as shown in the experimental result.In other words, the scope of human hearing is about 20～20000kHz.So,, then can be easily produce whole human earshot to result from the form of new sound wave of heterodyning if bandwidth is wide to being enough to comprise at least 20000kHz.Thereby, having thereon the acoustic intelligence of modulation, and will cause new acoustical signal with the signal of appropriate carrier wave interference, described new acoustical signal can produce audible sound in the whole audible spectrum of human hearing.
Except using thinner piezoelectric membrane 104 to increase the resonance frequency, also exist alternate manner to come extended frequency range.For example, in alternative, the present invention uses has the more unit 124 of the aperture 112 of minor diameter.For the driving voltage that applies, littler aperture also will cause higher resonance frequency.
Though some result has been described, has checked that it also is useful being enough to represent dynamic (dynamical) some equation of the present invention.Please refer to about the theory analysis of membrane tension and resonance frequency and to carry a work through the press:
Vibrating Systems and their Equivalent Circuits, ZdenekSkvor, 1991 Elsevier,
Marks Standard Handbook for Mechanical Engineers, Ninth Edition, Eugene A.Avallone and TheodoreBaumeister III and
Theory of Plates and Shells, StephenTimoshenko, second edition.The Marks handbook has provided very useful equation (5.4.34), and described equation makes the tension force in the film relevant with resonance frequency.Resonance frequency is hole shape, orifice size, back pressure, film compliance and density of film.Relation between these numerical value is complicated and exceeded the scope of this document.
Fig. 6 represents an alternative embodiment of the invention, but this embodiment also produces frequency by emission drum transducer 116, and its structure fundamental sum preferred embodiment is identical.Essential distinction is to replace to produce vacuum in emission drum transducer 116, now to launching the internal pressurization of bulging transducer 116.Piezoelectric membrane 104 is in the inboard of the surface of emission, and part is in place by the pressure fixing in the emission drum.
The pressure of introducing in the emission drum transducer 116 can be changed, thereby changes resonance frequency.But the thickness of piezoelectric membrane 104 remains the key factor of determining to apply much pressure.This can partly think to replace the PVDF of the twin shaft tensioning used in a preferred embodiment, and these piezoelectric membranes that sizable anisotropic some copolymer makes cause by having.The adverse side effect of anisotropy piezoelectric membrane is that in fact it can stop the vibration of film on all directions, causes asymmetricly, and this asymmetric meeting causes the distortion of the signal that produces from film.Therefore, PVDF is preferred piezoelectric film material, not only because it has the yield strength more much higher than copolymer, and because its anisotropic properties is lower.
A generation that the aspect can be frequency resonance or excitation of the alternative of pressurization emission drum transducer 116.This is owing to launching the generation of rousing echoes in the transducer 116, and described echo produces to result from launches the ripple of making that rouses in the transducer 116 interior gases.But, also determine can eliminate echo by in emission drum transducer 116, placing the material that absorbs echo.For example, a foam rubber 134 in the insertion emission drum transducer 116 or other sound-absorbing material or acoustic damping material can be eliminated all frequency stimulations usually.On the other hand, can be placed on backboard near the piezoelectric membrane, closely to the ripple of making that is enough to fully eliminate in the particular range of being concerned about.
Utilize the experimental result of pressurization emission drum transducer 116 to show that under typical pressure of selecting and driving voltage emission drum transducer 116 is worked in fact in the range of linearity.For example, determine that the pressure in emission drum transducer 116 is under the situation of 10 pounds/square inch (psi), utilize the emission drum transducer 116 of the PVDF of 28 micron thickness to produce to rouse transducer 116 for the emission of 5psi and compare big approximately 43% resonance frequency with interior pressure.On the other hand, confirm when determine to drive amplitude double the displacement of PVDF is doubled the time, the linear zone of discovery work.
Be determined by experiment pressurization emission drum transducer 116 in addition and can obtain to be about 20% bandwidth usually.So structure only has the emission of the resonance frequency of 100kHz and rouses the bandwidth that transducer 116 causes about 20kHz, is enough to produce the gamut of human hearing far away.By carrying out acoustic damping to launching bulging transducer 116 inside, prevent to introduce echo distortion or postwave (rearwave) resonance, pressurization embodiment also can obtain the volume result of the unforgettable viable commercial of the preferred embodiment of the present invention.
The preferred thickness, aperture size and the drum that the following describes piezoelectric membrane are pressed.When pressure increases, it will increase the resonance frequency of loud speaker.Also can increase resonance frequency by the thickness that reduces aperture size or increase piezoelectric membrane.Following table represents to provide some preferred film thickness, aperture size and the pressure of the resonance frequency of 35kHz.For the present invention, these concrete parameters provide maximum output.Obviously can use within these scopes or near various combinations.
| Thickness | The aperture | Drum is pressed |
| 9 microns | 0.160 inch | 5PSI |
| 12 microns | 0.168 inch | 6PSI |
| 25 microns | 0.200 inch | 12PSI |
Though table 1 has been enumerated the pore size of selecting, but preferred pore size is 0.050 inch～0.600 inch.The parameter of enumerating in the table 1 mainly concentrates on the ultrasonic transducer.The actual performance of film depends on different factors, for example film be twin shaft, single shaft or apply or the like.For example, for 0.160 inch aperture, 9 micron films that use under 5PSI produce the resonance frequency of 35kHz.On the contrary, for the same resonance frequency that produces 35kHz, under 5PSI, another 9 micron film that applies the PVDC coating must have 0.600 inch aperture.Though the above-mentioned example of orifice size is at ultrasonic wave embodiment of the present invention, but also can use bigger aperture directly to produce useful audio frequency.
Spacing between the aperture center is preferably in 1/4～1/2 (between 1/4～1/2wL) of frequency wavelength that is output as target with maximum.Preferred distance between the aperture center is 1/3 of the frequency wavelength under the maximum output situation of needs.
Another favourable aspect of the present invention is with respect to concrete application the adaptability of acoustic transmitter shape.For example, as long as can in disk plane, make piezoelectric membrane keep even tensioning state, just can construct the emission drum of arbitrary shape.This design feature allows according to providing unique designer's shape of decorating to prepare loadspeaker structure for room or other environment.Owing to need minimum space, therefore by be installed in the corner, annular shape (perimetershape) between the pillar is as the part with wall-mounted equipment of supporting high-fidelity equipment etc., can make thickness less than 1 inch loud speaker.By according to isotropism mode oriented film in the plane, subsequently film is bonded in the periphery of disk plane, can realize the uniformity of the tension force of irregularly shaped interior transmitting film.Excision subsequently or folding unnecessary thin-film material, and utilize circular belt sealing, thus tie up on antetheca and rear wall, and the drum wall is placed the centre of entire package.This loud speaker is in light weight, and the lead that is used for received signal that only need be coupled on the piezoelectric connects, and applies vacuum or malleation, thereby makes film expand into the pressure piping of arc.
Referring to the more specifically realization of the preferred embodiments of the present invention, emission drum transducer 100 can be included in the system shown in Fig. 7.This applications exploiting parameter or heterodyning technology, described technology is particularly suitable for current membrane structure.According to parameter loud speaker theory, piezoelectric membrane is very suitable for working under higher supersonic frequency.
Basic system comprises oscillator or the digital ultrasound wave source 20 that first-harmonic or carrier wave 21 are provided.Ripple 21 is commonly called first ultrasonic wave or prima.Am component 22 couples with the output of supersonic generator 20, and receives fundamental frequency 21, so that and audio frequency or 23 mixing of infra-acoustic frequency input signal.Can simulate or the numeral form audio frequency or infra-acoustic frequency signal are provided, audio frequency or infra-acoustic frequency signal can be the sound from music or other form of any conventional signal source 24.If input signal 23 comprises sideband up and down, then in modulator, can comprise a filtering unit, thereby under the modulated carrier frequencies of selected bandwidth, produce band single side output.
Emission drum transducer is represented as object 25, makes emission drum transducer 25 send supersonic frequency f with the form of the new waveform propagated on the surface of thin film transducer 25a
1And f
2This new waveform interacts in non-linear air dielectric, thereby produces difference frequency 26 with new sound wave or infrasonic form.The ability that a large amount of radiated elements are formed in the emission disk is particularly suitable for the preceding generation of homogeneous wave, can propagate high-quality audio frequency output and eloquent volume before the described homogeneous wave.
Because according to the principle of sound heterodyning, corresponding to f
1And f
2Compressional wave in air, disturb, so the present invention can have an effect as mentioned above.To a certain extent, the sound heterodyning is the mechanical homologue of the electric heterodyning effect that produces in nonlinear circuit.For example, the amplitude modulation in the circuit is the heterodyning process.Heterodyne process itself only is the generation of two new ripples.New ripple is two first-harmonic sums and poor.
With regard to the sound heterodyning, when at least two ultrasonic compressional waves interact or disturb, observe the new ripple that equals first-harmonic sum and difference aloft.Preferred transmission medium of the present invention is an air, because air is the highly compressible medium of making nonlinear response under different condition.Air this non-linear makes it possible to produce the heterodyning process, eliminates influencing each other of difference signal and ultrasonic output.But, should remember that if desired compressible any fluid all can be used as transmission medium.
And the successful generation of parametric difference xor signal seems only have minimum volume in the prior art, and structure of the present invention produces maximum sound.Can arrive distance quite far away to audio emission with unforgettable volume though transmit the single transducer of AM modulation fundamental frequency, the combination of some collinear signals has enlarged markedly volume.When directive metope or other plane of reflection, volume is so big and directivity is so arranged, and is exactly that sound generation source is launched this sound as metope consequently.
A key character of the present invention is to propagate fundamental frequency and single or two sidebands from identical transducer face.So partial wave is correctly calibrated.In addition, phase alignment is in highest level, and high interference levels possible between two different supersonic frequencies is provided.By the maximum interference of between these ripples, guaranteeing, realize maximum energy transfer with respect to air molecule, in the parameter loud speaker, described air molecule becomes " loud speaker " radiant element effectively.Therefore, the inventor thinks the enhancing of these factors in the film, and the array of ultrasonic transmitters that provides among the present invention obtains the wonderful increase in audio output signal volume aspect.
Compare with conventional speaker system, the generation of full volume provides important advantage in the parameter loud speaker.The more important thing is the fact of reproducing sound by the less radiant element of quality.Specifically, do not exist in any radiant element of work in the audiorange, because piezoelectric membrane vibrates under supersonic frequency.Produce this feature of sound by the sound heterodyning and can eliminate conventional distortion effect substantially, the described distortion effect overwhelming majority is caused by the radiant element of conventional loud speaker.For example, because the distance that moves around of low quality film is several microns, anti-harmonic wave and standing wave on diffuser, cone spike (overshoot) and the cone undershoot (undershoot) have therefore been eliminated substantially.
Represented another alternative of the present invention among Fig. 8.Understand the present invention in a preferred embodiment and how to play a part after the reflector, obviously this alternative can be used as receiver or transducer equally.This is that piezoelectric membrane not only can convert electric energy to mechanical energy, and can convert mechanical energy to the result of electric energy.So the equipment of preferred embodiment only is modified aspect following, replace the signal source 122 with 100 couplings of emission drum transducer, sensing drum (sensing drum) is linked to each other with sensing instrument such as oscilloscope.Subsequently, transducer 118 converts the compressional wave of penetrating on the piezoelectric membrane 104 of sensing drum transducer 118 to the signal of telecommunication, 104 efficient Mike's wind actions of film in fact.
Fig. 9 represents to have the loud speaker that is positioned at rigidity emission dull and stereotyped 152 echo enhancing structure 150 afterwards.The distance that echo strengthens structure and piezoelectric membrane is preferably 1/4 of the distance of selecting wavelength, is expressed as 1/4wL among Fig. 9.This enhancing structure helps the actual sound wave or the hyperacoustic generation that are produced, because echo strengthens the structure signal that reflected phase will echo (phasebackwave) is outer, thereby the phase place echo becomes the phase wave with the prima that produces with respect to environment.If it is not bonnet 110 that echo strengthens structure, then strengthens structure and also will comprise the aperture 154 of being convenient to isostasy.Figure 10 has represented a kind of alternative construction of this embodiment, and wherein echo enhancing structure is a bonnet 110.Distance apart from 1/4 wavelength of piezoelectric membrane depends on the required frequency wavelength that will strengthen.Modal is carrier frequency or resonance frequency with the wavelength that is enhanced.When taking place to strengthen at distance piezoelectric membrane 1/4 wavelength place, the final output of reflector can increase up to 3dB.What will replenish emphatically is the wavelength of the frequency that strengthens as required, and echo strengthens structure also can be placed on the different place of tripping conductive film distance.Other two kinds desirable enhancing distances are apart from piezoelectric membrane 1/2 wavelength and 1 wavelength.
Another embodiment of the present invention is used non-circular aperture.Since the symmetric shape of circular aperture, so circular aperture is effective, but also can use other symmetric shape.Figure 11 represents to use the rigidity emission dull and stereotyped 156 of rectangle aperture 158.Figure 12 represents to have the rigidity emission dull and stereotyped 160 of oval aperture 162.For anisotropy or single shaft film, rectangle or ellipse are effective especially.This is because when piezoelectric membrane shrinks or expands perpendicular to rectangle or oval-shaped major axis, can produce significant wave.
Figure 13 is the embodiment of the loud speaker of lobed expelling plate.The convex shape of reflector allows to disperse the sound of generation in the zone more vast than plane embodiment.Along with the increase of surface of emission mean curvature, discrete areas also increases.On the contrary, Figure 14 has represented to concentrate on the direction-sense spill expelling plate of loud speaker.
Figure 15 has the crooked expelling plate 180 of the sound that disperses transmitter unit 182 generations.Piezoelectric membrane 184 is arranged under the expelling plate 180, thus inner chamber 186 pressurized formation dome element.Apply the direct current audio signal by the lead 188 that links to each other with electric contact 190, described electric contact is descending between locular wall 192 and expelling plate 180.The bonnet 194 of inner chamber also is crooked, and the distance that is arranged on piezoelectric membrane is the position of 1/4 selected frequency.Selected frequency is the frequency that will be strengthened by echo.Figure 16 comprises having flat surface and curved bottom, thereby produces the expelling plate 200 of spill piezoelectric membrane 204 configurations.Bonnet 206 is straight, and pressurized by the inner chamber 208 of cydariform one-tenth, thereby forms foregoing arch emission element.Obviously according to disclosure document, if desired, also can projection or the crooked bonnet 206 of form of depression or the surface of expelling plate 200.
In another embodiment of the present invention, the electrode on the expelling plate is not complete annulus.Figure 17 represents to have the surface of emission 170 for semicircular two electric contacts.First electric contact 171 and second electric contact 172 can have the independent signal that is applied thereto.This allows each zone of independent control piezoelectric membrane.Can carry out phase shift to the signal that is applied on the different electric contacts, thereby produce corresponding ripple aloft through phase shift.When these adjacent ripples through phase shift interacted under ultrasonic level, it had changed the wave line of propagation route.By forming appropriate phase relation, " manipulation " acoustic beam can not carried out to loud speaker under the situation that physics moves.This provides mobile effect for the user.In addition, by electric contact 174,176 independently, also can apply a plurality of passages.
Figure 18 represents to have the surface of emission 170 of four electric contacts 182,184,186,188.Though only represented four contacts, but the number of contact only is subjected to the size and the numerical limitations in the zone of desired control.The electric contact of processing on the surface of emission is many more, and is big more to the control of independent piezoelectric regions.Each separate unit even can have its electric contact.Will be appreciated that electrode sputter or flow technique based on routine in addition, the restricted hardly contact arrangement of number is possible.
Other two important embodiment of steric electric contact on piezoelectric membrane have been represented to use among Figure 19 and 20.Figure 19 represents to have two piezoelectric membranes 210 that electrically contact ring 212,214 with one heart.With regard to preferred realization, centering ring 214 approximately comprises 1/2, the second of the whole area of a circle and electrically contacts ring around whole annulus 214.These two electrically contact ring and all can receive the independent signal of telecommunication from lead 218 and 216.Signal can be controlled or the spatial sound orientation thereby produce wave beam by phase shift.In addition, one independently passage can be used for each electrode.For example, a passage can be sent to centering ring, voice-grade channel for example, and second channel can be sent to second annulus subsequently, for example environmental background sound.In fact, this routine sound intermediate frequency passage and background sound channel are mixed on piezoelectric membrane.Figure 20 represents to have the alternative arrangement of the electric contact embodiment of three electric contacts 220,222,224.Extra contact has increased the control that can put on the piezoelectric membrane.
The conventional method of making piezoelectric membrane is to whole thin film sputtering metal coating.Using the defective of the lip-deep metal coating of whole piezoelectric membrane is when applying voltage, and some zone that some of film should not move or can not move at an easy rate is driven.For example, some part of film may be under anchor clamps, under screw or on otherwise attached to the surface of emission.When irremovable zone is driven, can produce undesirable heat.The present invention, addresses this problem essential regional sputter or metallizing coating by only.Do not answer driven zone and zone fastened or that clamping is in place not to be metallized.Referring now to Figure 28,, represented among the figure that piezoelectric membrane will be by sputter 252 selectively, so that conform to the aperture 250 of the surface of emission, and the zone that should not move on the film will be avoided by sputter.Certainly, each metallized area must be electrically connected with other metallized area, and this realizes necessary words by metallization bridge contact 254.
Another problem be positioned at below the screw or contact regions near metallized area may form arc.Can according to avoid and arbitrarily the hold down assembly mode that forms arc of conduction the circumference of film is applied the selectivity sputter.Only metallized in the effective coverage and also reduce the electric capacity of the amplifier that needs driving.Can utilize the application choice sputter effectively of well-known mask technique.
Figure 21 represents attached to a polygon piezoelectric membrane on the expelling plate.Bigger circular membrane is compared, and the polygon film is easier to make and processing.Another advantage of utilizing less geometry to obtain is can be the less film combinations of a plurality of geometries together, thereby produce the bigger surface of emission, and this has alleviated the problem (for example tensioning problem) that occurs in producing a bigger transmitting film.Figure 22 represents to combine, thereby forms three polygon films of a longer surface of emission.Obviously also can select less regular geometric shapes arbitrarily, and inlay these less regular geometric shapes films subsequently, thereby form the bigger surface of emission.
Figure 23 has represented to combine in the hexagon ring, thereby produces six polygon piezoelectric membranes of reflector.Ring 240 center is not effective emitter region, can be empty or can be some other non-piezoelectric material.The wonderful result of structure shown in Figure 23 is that it can produce 80%～90% of hexagon loud speaker output with active centre district.The piezoelectric membrane area of structure shown in Figure 23 just have the active centre district the hexagon loud speaker the piezoelectric membrane area 50%, but output only reduced by 10%～20%.
Figure 24 and 25 has represented that the less rectangle piezoelectric membrane of use of the present invention partly forms two embodiment of bigger reflector shape.Figure 24 represents to be combined into foursquare four rectangle parts with center drilling.This structure has the same advantage about the explanation of hexagon ring.Figure 24 represents to finish four rectangle parts of composition-seies.Preferably use more in addition or even piezoelectric membrane part still less, and they are combined into the geometry arrangement of the bigger output of generation.
Figure 26 represents to have the piezoelectric membrane reflector 230 away from the small pressure chamber 232 of some piezoelectric membranes unit 234.Pressure chamber 232 is equal to single high pressure chest, and links to each other with piezoelectric membrane unit 234 by thin force pipe.Force pipe 236 sends the pressure from pressure chamber 232, thereby makes the piezoelectric membrane on each unit 234 form arch reflector shape.In order to make piezoelectric membrane form its arcuate in shape, each piezoelectric membrane unit must have enough pressure.The benefit that use has the pressure chamber 232 of force pipe 236 is to avoid the barometric gradient along slender pipeline to lose.Because the set area of force pipe 236 is quite little, the use of force pipe can not reduce pressure, but gives each corresponding transmitter unit 234 pressure distribution.In addition, because less volume only needs less pressure chamber source in the pipeline, so the size of pressure chamber 232 is also quite little.On the other hand, can be under the situation that does not have pressure chamber or particular pressure source, directly the pipeline to interconnection pressurizes.In addition, the number of piezoelectric membrane unit 234 and pipeline 236 and arrangement only are subjected to the restriction of physical constraint condition.
The seal coating of explanation as shown in Fig. 3 c and 3d also will be discussed the method that seals piezoelectric membrane in addition in more detail below.With reference now to Figure 27,, represented the structure of the piezoelectric membrane of sealing among the figure.The intermediate layer is a piezoelectric membrane 240.This film is PVDF film or similar piezoelectric copolymers normally.Encapsulant 246 is coated on the PVDF.Encapsulant is the PVDC (polyvinylidene chloride) with high vapor barrier properties.Can immerse in the PVDC coating liquid by brushing, air-brush or PVDF, PVDC is coated on the piezoelectric membrane.In addition, also can make piezoelectric membrane charged before or afterwards, PVDC is coated on the piezoelectric membrane.PVDC is adhered in the structure of piezoelectric membrane, and forms the effective barrier that stops gas to pass through piezoelectric membrane 240.After being coated to PVDC on the piezoelectric membrane, can or be evaporated on the piezoelectric membrane 240 electrode 242 and 244 sputters.Also can after being plated on the piezoelectric membrane, apply encapsulant (PVDC) to electrode.
According to the above description, under the situation that needn't seek help from the sound heterodyning processing that illustrates previously, preferably reach alternative and obviously can directly send audio frequency.But the frequency range in the audible spectrum must be confined to higher frequency usually, because the present invention is more effective in intermediate frequency and high frequency.So,, when the present invention is used to produce the audio frequency of gamut, realize great advantage of the present invention when by using the heterodyning of aforesaid sound indirectly.
Understand just illustrating of the foregoing description to the application of the principles of the present invention.Under the situation that does not break away from the spirit and scope of the present invention, those skilled in the art can design various modifications and alternative arrangement.Additional claim intention covers such modification and arrangement.
Claims (68)
1, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Have the outer surface of outside orientation and the rigidity expelling plate of inner surface, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided; With
The pressure apparatus that couples with expelling plate, be used for forming bias voltage, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the film at aperture place.
2, according to the described loud speaker of claim 1, also comprise the polymer thin coating on the piezoelectric membrane, wherein said polymer thin coating sealing piezoelectric membrane prevents the pressure seepage.
3, according to the described loud speaker of claim 2, wherein said polymer thin coating is a polyvinylidene chloride.
4, according to the described loud speaker of claim 1, also comprise the heavy inert gas in the pressure apparatus, wherein said heavy inert gas reduces the gas permeation by piezoelectric membrane.
5, according to the described loud speaker of claim 4, wherein the heavy inert gas is a nitrogen.
6, according to the described loud speaker of claim 1, wherein aperture has the center, and the distance between the aperture center is 1/4～1/2 of the wavelength of selected frequency.
7, according to the described loud speaker of claim 1, wherein the rigidity expelling plate is protruding, so that dispersive wave output.
8, according to the described loud speaker of claim 1, wherein the rigidity expelling plate is a spill, so that concentrate ripple output.
9, according to the described loud speaker of claim 1, wherein hole diameter is 0.050～0.600 inch.
10, according to the described loud speaker of claim 1, wherein the bias voltage in the pressure apparatus is about 0～20 pound/square inch.
11, according to the described loud speaker of claim 1, also comprise pressure seal around the piezoelectric membrane periphery, wherein pressure seal is used as the electrical contact arrangement of drive pressure conductive film.
12, according to the described loud speaker of claim 1, wherein piezoelectric membrane thickness is about 9 microns, and hole diameter is about 0.160 inch, and bias voltage is about 5 pounds/square inch, wherein produces the resonance frequency that is about 35kHz.
13, according to the described loud speaker of claim 1, wherein piezoelectric membrane thickness is about 12 microns, and hole diameter is about 0.168 inch, and bias voltage is about 6 pounds/square inch, wherein produces the resonance frequency that is about 35kHz.
14, according to the described loud speaker of claim 1, wherein piezoelectric membrane thickness is less than 25 microns, and hole diameter is less than 0.200 inch, and bias voltage wherein produces the resonance frequency that is about 35kHz～60kHz less than 12 pounds/square inch.
15,, comprise also piezoelectric membrane is clipped in clamping part on the rigidity expelling plate that wherein said clamping part has the some clamping apertures corresponding to the some apertures in the surface of emission according to the described loud speaker of claim 1.
16, according to the described loud speaker of claim 1, also comprise the drum of common hollow with the relative device of sidewall with first and second, wherein the rigidity expelling plate is fixed on the first bulging end, the cavity arrangements of interior face drum.
17, according to the described loud speaker of claim 16, wherein pressure apparatus couples with drum, so that form positive bias with respect to the film at aperture place.
18 according to the described loud speaker of claim 1, also comprises:
Apply the supersonic frequency generating means of ultrasonic signal to piezoelectric membrane;
The audio frequency generating means of the acoustical signal that will be modulated into ultrasonic signal is provided;
Couple with the supersonic frequency generating means harmony generating apparatus that takes place frequently, utilize the sound wave of modulation to form the modulating device of ultrasonic carrier;
Couple with modulating device, carrier wave and modulation sound wave are offered piezoelectric membrane, so that produce the emitter of corresponding compressional wave in the expelling plate excitation.
19, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Usually middle hollowing with sidewall and first and second opposite end;
Be fixed on the rigidity expelling plate of the first bulging end, described expelling plate has the outer surface of outside orientation and towards the inner surface of cavity arrangements of drum, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided;
With the pressure apparatus that couples of drum, be used for forming bias voltage with respect to the film at aperture place, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into; With
Be arranged in the bulging inner chamber, and apart from the piezoelectric membrane certain distance, thereby the ripple that strengthens the frequency of selecting strengthens structure.
20, according to the described loud speaker of claim 19, its medium wave strengthens second opposed end of structural configuration at drum.
21, according to the described loud speaker of claim 19, its medium wave strengthens the distance that structure and the distance of piezoelectric membrane are served as reasons and selected in the group of 1/4,1/2 or 1 wavelength formation selecting frequency.
22, according to the described loud speaker of claim 19, the distance that its medium wave strengthens structure and piezoelectric membrane is a distance of selecting in the group that constitutes of 1/4,1/2 or 1 wavelength by carrier frequency.
23, according to the described loud speaker of claim 19, the distance that its medium wave strengthens structure and piezoelectric membrane is a distance of selecting in the group that constitutes of 1/4,1/2 or 1 wavelength by resonance frequency.
24, according to the described loud speaker of claim 19, its medium wave strengthens the structure camber.
25, according to the described loud speaker of claim 19, also comprise:
The supersonic frequency generating means of ultrasonic signal is provided to piezoelectric membrane;
The audio frequency generating means of the acoustical signal that will be modulated on the ultrasonic signal is provided;
Couple with the supersonic frequency generating means harmony generating apparatus that takes place frequently, utilize the sound wave of modulation to form the modulating device of ultrasonic carrier;
Couple with modulating device, carrier wave and modulation sound wave are offered piezoelectric membrane, so that produce the emitter of corresponding compressional wave in the expelling plate excitation.
26, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Have the outer surface of outside orientation and the rigidity expelling plate of inner surface, described expelling plate has between surfaces externally and internally and extends, and has some apertures of definite shape;
Wherein hole shape is rectangle or ellipse, and has major axis;
Pass the isotropism piezoelectric membrane of the aperture arrangement of expelling plate, thereby the axle of mechanical stress is perpendicular to the major axis of hole shape;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided; With
The pressure apparatus that couples with expelling plate, be used for forming bias voltage with respect to the film at aperture place, film expand into to respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch, thereby produce the arch emitter structures of compressional wave around in the environment.
27, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Have the outer surface of outside orientation and the rigidity expelling plate of inner surface, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
Couple with piezoelectric membrane, at least two electrodes of the electric input that applies are provided; With
The pressure apparatus that couples with expelling plate, be used for forming bias voltage, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the film at aperture place.
28, according to the described loud speaker of claim 27, wherein said at least two electrodes are on the separate edge of piezoelectric membrane, and wherein said electrode can be used for the isolated area of independent control piezoelectric membrane.
29, according to the described loud speaker of claim 27, wherein said at least two electrodes are at least two concentric rings.
30, according to the described loud speaker of claim 27, also comprise the drum of common hollow with the relative device of sidewall with first and second, wherein the rigidity expelling plate is fixed on the first bulging end, the cavity arrangements of interior face drum.
31, according to the described loud speaker of claim 27, wherein pressure apparatus couples with drum, so that form positive bias with respect to the film at aperture place.
32, according to the described loud speaker of claim 27, also comprise:
The supersonic frequency generating means of ultrasonic signal is provided to piezoelectric membrane;
The audio frequency generating means of the acoustical signal that will be modulated on the ultrasonic signal is provided;
Couple with the supersonic frequency generating means harmony generating apparatus that takes place frequently, utilize the sound wave of modulation to form the modulating device of ultrasonic carrier;
Couple with modulating device, carrier wave and modulation sound wave are offered piezoelectric membrane, so that produce the emitter of corresponding compressional wave in the expelling plate excitation.
33, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Rigidity expelling plate, described rigidity expelling plate have outer surface and the some transmitter units that are formed in the expelling plate, and wherein each transmitter unit has independently pressure chamber and the aperture that passes outer surface;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
The plurality of conduits of interconnection transmitter unit;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided; With
The pressure apparatus that couples with described plurality of conduits, be used for forming bias voltage, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the piezoelectric membrane at aperture place.
34, a kind of sealing piezoelectric membrane prevents the method for gas by piezoelectric membrane, comprising:
(a) provide piezoelectric membrane; With
(b) the polymer thin coating is bonded at least one side of piezoelectric membrane, thereby seals piezoelectric membrane and prevent that gas from passing through film.
35, according to the described method of claim 34, also be included in the step that adds top electrode on polymer thin coating and the piezoelectric membrane.
36, according to the described method of claim 34, also be included in before the cohesive polymers shallow layer, on piezoelectric membrane, add the step of top electrode.
37, according to the described method of claim 34, wherein the polymer thin coating is polyvinylidene chloride (PVDC) layer.
38, according to the described method of claim 34, wherein piezoelectric membrane is polyvinylidene fluoride (PVDF) layer.
39, according to the described method of claim 38, the step that wherein applies polyvinylidene chloride (PVDC) also comprises the step that use is selected from the group that comprises brushing, air-brush or dip-coating.
40, according to the described method of claim 34, wherein step (c) also is included on PVDC layer and the piezoelectric membrane and adds top electrode according to selected pattern, should be by the step in electrically driven (operated) zone thereby avoid.
41, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Have the outer surface of outside orientation and the rigidity expelling plate of inner surface, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided; With
The pressure apparatus that couples with the rigidity expelling plate, be used for forming positive bias, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the film at aperture place.
42, according to the described loud speaker of claim 41, wherein under the aperture of expelling plate, piezoelectric membrane is disposed on the inner surface.
43, according to the described loud speaker of claim 41, also comprise the polymer thin coating on the piezoelectric membrane, wherein said shallow layer sealing piezoelectric membrane prevents the pressure seepage.
44, according to the described loud speaker of claim 43, wherein said polymer thin coating is polyvinylidene chloride (PVDC).
45, according to the described loud speaker of claim 41, also comprise the heavy inert gas in the pressure apparatus, wherein said heavy inert gas reduces the gas permeation by piezoelectric membrane.
46, according to the described loud speaker of claim 45, wherein the heavy inert gas is a nitrogen.
47, according to the described loud speaker of claim 41, wherein aperture has the center, and the distance between the aperture center is 1/4～1/2 of the wavelength of selected frequency.
48, according to the described loud speaker of claim 41, wherein the rigidity expelling plate is protruding, so that dispersive wave output.
49, according to the described loud speaker of claim 41, wherein the rigidity expelling plate is a spill, so that concentrate ripple output.
50, according to the described loud speaker of claim 41, wherein hole diameter is 0.050～0.600 inch.
51, according to the described loud speaker of claim 41, wherein the positive bias in the pressure apparatus is about 0～20 pound/square inch.
52, according to the described loud speaker of claim 41, wherein piezoelectric membrane thickness is about 9 microns, and hole diameter is about 0.160 inch, and positive bias is about 5 pounds/square inch, wherein produces the resonance frequency that is about 35kHz.
53, according to the described loud speaker of claim 41, wherein piezoelectric membrane thickness is about 12 microns, and hole diameter is about 0.168 inch, and positive bias is about 6 pounds/square inch, wherein produces the resonance frequency that is about 35kHz.
54, according to the described loud speaker of claim 41, wherein piezoelectric membrane thickness is less than 25 microns, and hole diameter is less than 0.600 inch, and bias voltage wherein produces the resonance frequency that is about 35kHz～60kHz less than 12 pounds/square inch.
55,, comprise also film is clipped in clamping part on the rigidity expelling plate that wherein said clamping part has the some clamping apertures corresponding to the some apertures in the surface of emission according to the described loud speaker of claim 41.
56, according to the described loud speaker of claim 41, also comprise being arranged in the bulging inner chamber, and apart from the piezoelectric membrane certain distance, thereby the ripple that strengthens the frequency of selecting strengthens structure.
57, according to the described loud speaker of claim 56, its medium wave strengthens second opposed end of structural configuration at drum.
58, according to the described loud speaker of claim 56, its medium wave strengthens the distance of distance for selecting of structure and piezoelectric membrane from 1/4,1/2 or 1 group that wavelength constituted by the selection frequency.
59, according to the described loud speaker of claim 56, its medium wave strengthens the distance of distance for selecting of structure and piezoelectric membrane from 1/4,1/2 or 1 group that wavelength constituted by carrier frequency.
60, according to the described loud speaker of claim 56, its medium wave strengthens the distance of distance for selecting of structure and piezoelectric membrane from the group that 1/4 wavelength by carrier frequency is constituted.
61, according to the described loud speaker of claim 56, its medium wave strengthens the distance of distance for selecting of structure and piezoelectric membrane from 1/4,1/2 or 1 group that wavelength constituted by resonance frequency.
62, according to the described loud speaker of claim 56, its medium wave strengthens the distance of distance for selecting of structure and piezoelectric membrane from the group that 1/4 wavelength by resonance frequency is constituted.
63, according to the described loud speaker of claim 56, it is arc that its medium wave strengthens structure.
64, according to the described loud speaker of claim 41, also comprise:
The supersonic frequency generating means of ultrasonic signal is provided to piezoelectric membrane;
The audio frequency generating means of the acoustical signal that will be modulated onto on the ultrasonic signal is provided;
Couple with the supersonic frequency generating means harmony generating apparatus that takes place frequently, utilize the sound wave of modulation to form the modulating device of ultrasonic carrier;
Couple with modulating device, carrier wave and modulation sound wave are offered piezoelectric membrane, so that produce the emitter of corresponding compressional wave in the expelling plate excitation.
65, a kind of loud speaker of launching infrasonic sound compressional wave, acoustic compression ripple or ultrasonic compressional wave, described loud speaker comprises:
Drum with common hollow of sidewall and first and second opposed end;
Be fixed on the rigidity expelling plate of the first bulging end, described expelling plate has the outer surface of outside orientation and towards the inner surface of cavity arrangements of drum, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
Couple with piezoelectric membrane, the electrical contact arrangement of the electric input that applies is provided;
With the bulging pressure apparatus that couples, be used for forming back bias voltage, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the film at aperture place.
66,, wherein above the aperture of expelling plate, piezoelectric membrane is arranged on the outer surface according to the described loud speaker of claim 65.
67, a kind of being used for produces at least one new audio frequency or subaudible system indirectly from least two supersonic frequencies of different numerical value, and described system comprises:
Have the outer surface of outside orientation and the rigidity expelling plate of inner surface, described expelling plate has the some apertures that extend between surfaces externally and internally;
Pass the piezoelectric membrane of the aperture arrangement of expelling plate;
The pressure apparatus that couples with expelling plate, be used for forming bias voltage, can respond the variation that is applied to the electric input on the piezoelectric membrane and shrink and stretch the arch emitter structures that produces compressional wave in the environment around thereby film expand into respect to the film at aperture place; With
Couple with piezoelectric membrane, be used for electrical contact arrangement in described some apertures and relevant arch radiated element formation vibratory response, wherein said vibration plays propagation (i) first supersonic frequency and (ii) the supersonic frequency reflector of second supersonic frequency simultaneously, described second supersonic frequency and first supersonic frequency interact, thereby propagate difference frequency in vocal cords are wide.
68, according to the described system of claim 67, thereby wherein said electrical contact arrangement comprises with film and couples the modulating device that the signal of telecommunication is provided, the described signal of telecommunication is used for producing first and second supersonic frequencies with the form of the modulation output of input supersonic frequency and audio frequency, and the difference of described first and second supersonic frequencies equals described at least one new audio frequency or infra-acoustic frequency.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US2000/000103 WO2001050810A1 (en) | 2000-01-04 | 2000-01-04 | Piezoelectric film sonic emitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1433661A true CN1433661A (en) | 2003-07-30 |
| CN1190107C CN1190107C (en) | 2005-02-16 |
Family
ID=21740943
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB008188386A Expired - Fee Related CN1190107C (en) | 2000-01-04 | 2000-01-04 | Piezoelectric film sonic emitter |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP1247421A4 (en) |
| JP (1) | JP2003520002A (en) |
| KR (1) | KR20020079767A (en) |
| CN (1) | CN1190107C (en) |
| AU (1) | AU2719000A (en) |
| CA (1) | CA2396347A1 (en) |
| HK (1) | HK1050102A1 (en) |
| WO (1) | WO2001050810A1 (en) |
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| CN104181231A (en) * | 2014-07-07 | 2014-12-03 | 西安交通大学 | Device and method for measuring yield behavior of thin film material |
| CN104822118A (en) * | 2015-05-06 | 2015-08-05 | 歌尔声学股份有限公司 | Packaging structure for MEMS microphones |
| CN105537091A (en) * | 2015-11-23 | 2016-05-04 | 西北工业大学 | Infrasonic wave synthetic method and device based on heterodyne frequency type and parametric acoustic array technology |
| CN106878882A (en) * | 2008-09-26 | 2017-06-20 | 诺基亚技术有限公司 | Dual mode speaker |
| CN107252312A (en) * | 2011-09-01 | 2017-10-17 | 微创医学科技有限公司 | Detect the method and portal hypertension monitoring system of portal vein and/or vena hepatica pressure |
| CN110234056A (en) * | 2019-06-21 | 2019-09-13 | 京东方科技集团股份有限公司 | Energy converter and preparation method thereof, transducing head |
| CN111044618A (en) * | 2019-12-05 | 2020-04-21 | 西安理工大学 | Piezoelectric sensor for detecting acoustic emission signals and preparation method of piezoelectric film |
| CN111669690A (en) * | 2020-07-10 | 2020-09-15 | 瑞声科技（南京）有限公司 | Piezoelectric microphone and preparation process thereof |
| CN114822482A (en) * | 2022-03-11 | 2022-07-29 | 南京师范大学 | Coupled acoustic vortex transmitter and application thereof |
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|---|---|---|---|---|
| EP1423051A4 (en) * | 2001-09-06 | 2011-09-28 | Pegasus Technologies Ltd | Cylindrical ultrasound receivers and transceivers formed from piezoelectric film |
| JP4947115B2 (en) * | 2009-09-30 | 2012-06-06 | 株式会社村田製作所 | Ultrasonic transducer |
| US20110264012A1 (en) * | 2009-10-23 | 2011-10-27 | Frans Lautzenhiser | Compliant couplant with liquid reservoir for transducer |
| US9116224B2 (en) | 2011-08-16 | 2015-08-25 | Nec Corporation | Electronic device |
| WO2019186321A1 (en) * | 2018-03-24 | 2019-10-03 | RAMCHANDRAN, Shankar Trichur | Wave shaping and scattering unit for an ultrasonic transducer |
| WO2019186305A1 (en) * | 2018-03-24 | 2019-10-03 | RAMCHANDRAN, Shankar Trichur | Transducer assembly |
| FR3087608B1 (en) * | 2018-10-17 | 2021-11-19 | Akoustic Arts | ACOUSTIC SPEAKER AND MODULATION PROCESS FOR AN ACOUSTIC SPEAKER |
| US11623248B2 (en) * | 2019-01-18 | 2023-04-11 | University Of Southern California | Focused ultrasound transducer with electrically controllable focal length |
| KR102267074B1 (en) * | 2019-11-11 | 2021-06-21 | 재단법인 파동에너지 극한제어 연구단 | Cover unit of ultrasonic transducer in acoustic extraordinary transmission type |
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| US4056742A (en) * | 1976-04-30 | 1977-11-01 | Tibbetts Industries, Inc. | Transducer having piezoelectric film arranged with alternating curvatures |
| FR2409654B1 (en) * | 1977-11-17 | 1985-10-04 | Thomson Csf | PIEZOELECTRIC TRANSDUCER DEVICE AND MANUFACTURING METHOD THEREOF |
| US4725994A (en) * | 1984-06-14 | 1988-02-16 | Kabushiki Kaisha Toshiba | Ultrasonic transducer with a multiple-folded piezoelectric polymer film |
| US4825116A (en) * | 1987-05-07 | 1989-04-25 | Yokogawa Electric Corporation | Transmitter-receiver of ultrasonic distance measuring device |
| DE3731196A1 (en) * | 1987-09-17 | 1989-03-30 | Messerschmitt Boelkow Blohm | FREQUENCY SELECTIVE SOUND CONVERTER |
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2000
- 2000-01-04 EP EP00905530A patent/EP1247421A4/en not_active Withdrawn
- 2000-01-04 CN CNB008188386A patent/CN1190107C/en not_active Expired - Fee Related
- 2000-01-04 WO PCT/US2000/000103 patent/WO2001050810A1/en not_active Application Discontinuation
- 2000-01-04 KR KR1020027008678A patent/KR20020079767A/en not_active Application Discontinuation
- 2000-01-04 JP JP2001551061A patent/JP2003520002A/en active Pending
- 2000-01-04 AU AU27190/00A patent/AU2719000A/en not_active Abandoned
- 2000-01-04 CA CA002396347A patent/CA2396347A1/en not_active Abandoned
-
2003
- 2003-03-28 HK HK03102258.0A patent/HK1050102A1/en unknown
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| CN104181231A (en) * | 2014-07-07 | 2014-12-03 | 西安交通大学 | Device and method for measuring yield behavior of thin film material |
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| CN114822482A (en) * | 2022-03-11 | 2022-07-29 | 南京师范大学 | Coupled acoustic vortex transmitter and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1247421A1 (en) | 2002-10-09 |
| HK1050102A1 (en) | 2003-06-06 |
| EP1247421A4 (en) | 2008-05-21 |
| AU2719000A (en) | 2001-07-16 |
| CA2396347A1 (en) | 2001-07-12 |
| KR20020079767A (en) | 2002-10-19 |
| WO2001050810A1 (en) | 2001-07-12 |
| CN1190107C (en) | 2005-02-16 |
| JP2003520002A (en) | 2003-06-24 |
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