CN1284414C - Capacitive transducer - Google Patents
Capacitive transducer Download PDFInfo
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- CN1284414C CN1284414C CNB018206239A CN01820623A CN1284414C CN 1284414 C CN1284414 C CN 1284414C CN B018206239 A CNB018206239 A CN B018206239A CN 01820623 A CN01820623 A CN 01820623A CN 1284414 C CN1284414 C CN 1284414C
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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
- H04R19/00—Electrostatic transducers
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
Abstract
A capacitive transducer, in particular a condenser microphone, with a ring-shaped member (12) and a diaphragm (11) secured to the ring-shaped member (12). A disc-shaped member (17) is secured in the opening of the ring-shaped member (12) and in parallel relationship to the diaphragm (11). The disc-shaped member (17) has an electrically conductive portion (19) spaced from the ring-shaped member (12) and facing the diaphragm (11) in a predetermined distance therefrom, whereby the diaphragm (11) and the electrically conductive portion (19) on the disc-shaped member (17) form an electrical capacitor. The second side of the disc-shaped member (17) and the contact member are directly accessible. Also, the ring-shaped member (12) has, outside the outer periphery of the diaphragm (11), a free surface (14) extending transversally to the axis of the ring-shaped member (12) for mounting in a microphone housing with the diaphragm flush with the front end of the microphone or slightly recessed relative to the front end.
Description
Technical field
The invention relates to capacitive transducer, capacitive microphone for example outside polarization type or the electret build, the electret build is the polarization type in advance known to promptly also.
Especially, the invention relates to the plate with two conductions or the capacitive transducer of two electrode type, in two plates or two electrodes one can move with respect to another plate or electrode that is considered to fixed electrode.This travelling electrode is assembled on the element of annular of a middle opening, thereby vibrating membrane covers on this middle opening, and fixed electrode is spaced between them in the middle opening of this ring-type element, maintains a bit of distance between fixed electrode and the travelling electrode.The present invention is for being used to measure with the science purposes, in uniformity, linearity, stability with to the condenser microphone that has higher requirements aspect the environmental change sensitivity special importance arranged.Hereinafter, term " capacitor " and " capacitive character " can mutual alternative be used.
The present invention be more particularly directed to be used for the capacitive transducer of the transducer such as condenser microphone.
Technical background
The most basic requirement that need satisfy for the microphone that is used to measure with the science purposes is that the acoustical behavior of this microphone necessarily will be got well, this just means, for the certainty of measurement that obtains, the linearity of microphone and stability will be got well, and microphone is wanted and can be well controlled and predict the interference and the influence of sound field to be measured simultaneously.
In addition, microphone is necessary that the environmental change such as temperature and static pressure is had very low sensitivity.In order to obtain result repeatably and to prolong interval between the calibration, this microphone also is necessary to show good short-term and long-term stability.In addition, must calibrate,, comprise its frequency response and sensitivity with the fundamental characteristics of this microphone of verification by simple method.In addition must be not only can be by directly measuring, but also can independently confirm to give one of the signal of having measured by expect the performance of this microphone based on Theoretical Calculation.
The condenser microphone that is used for science and measurement purpose is made of the mechanical organ of accurate processing usually.The main element of condenser microphone is a fixed electrode, is also referred to as back plate electrode and the travelling electrode as vibrating membrane, when static, keeps the distance of determining between this travelling electrode and the back plate electrode.Back plate electrode and vibrating membrane have constituted the electrode of capacitor together, this capacitor with common air as dielectric.In high-quality transducer, vibrating membrane is made of metal, and is assemblied in an end of microphone case usually.Microphone case, insulator and vibrating membrane have formed the space of a closure.When externally the pressure difference occurring between atmosphere and the closed space, vibrating membrane is moved, this moves and can cause changes in capacitance, and this variation can be by electric measurement.Frequency response at HFS is mainly determined by the resonance and its damping of vibrating membrane.This resonance frequency is by the quality and the decision of its mechanical tension of vibrating membrane.This damping depends on the mobility of the air in the space between vibrating membrane and back plate electrode, geometry that therefore can be by changing back plate electrode and by selecting between vibrating membrane and the back plate electrode suitable distance to change and controlling damping.Measure in the microphone at great majority, typical distance range is that 10 μ m are to 30 μ m between vibrating membrane and the back plate electrode.For individual types, in order to obtain the damping of uniform vibrating membrane displacement in domain of dependence, the range error between vibrating membrane and the back plate electrode must be controlled in ± 5% in.Usually control damping, the rear surface of these holes by on back plate electrode, boring some holes from the space one between vibrating membrane and the back plate electrode through to back plate electrode.The sensitivity of condenser microphone and interelectrode distance are directly proportional and the tension force of vibrating membrane is inversely proportional to.Because tension force depends on the range of extension of sheet metal, in order to obtain reasonable long-time stability, vibrating membrane must be fixed in very definite mode on the shell or ring-type element of microphone.
British patent GB2 112 605 discloses the condenser microphone of prior art, as shown in Figure 1.The microphone of this prior art has a columniform microphone case, and this shell has a transverse to support one and the coaxial interior cylindrical wall of microphone case.Disk by the annular that insulating material is made is pressed onto in the opening of interior cylindrical wall.The coating of layer of conductive material covers the middle body of the upper surface of insulation disk, and separates with interior cylindrical wall.This electric conducting material also covers the surface in the opening of circular disk, and the there has lead to be connected to coating.This lead is connected to terminals of microphone, this end and casing insulation.Conductive diaphragm is installed on the described end of shell, and leaves a bit of distance with the coating on the circular disk.
As shown in Figure 1, the microphone of prior art has some very big problems, exactly can test with characterization before, whole microphone must assemble earlier, and all elements of microphone all can produce very big influence to the temperature control of microphone, and this just means the material and the size of the element that must select all employings very carefully.The production of the microphone of prior art is also very expensive in addition, and the invention provides a kind of simple design, simply makes and lower price.
European patent EP 371 620 discloses a kind of low-cost microphone of using that typically is used for.This structure is cancelled required independently fixed electrode or back plate electrode by fixed electrode is incorporated in the shell.Reduce the component number in the low-cost microphone though this is a kind of good method, have a lot of reasons to make it be unsuitable in measuring microphone, using.
In these reasons some are to relate to aspect the requiring of error measuring microphone, and it requires two distance between electrodes ERROR CONTROL in ± 5%, and this requirement is inaccessible in such design; That is to say that be subjected to mechanical shock such as microphone owing to having dropped to suddenly on the ground, shell may be out of shape, this will cause the distance between vibrating membrane and the fixed electrode to change.In addition, the microphone of science and measurement purposes must have lower sensitivity to the variation of temperature, humidity and static pressure, and this requirement is difficult to reach in such design.In addition, in order to give a relatively independent affirmation of data of measuring, measuring the microphone requirement can be by predicting the performance of microphone based on Theoretical Calculation, and this requirement is difficult to reach in such design.
Summary of the invention
A problem in the prior art of above-mentioned discussion is, can test with characterization before, whole energy transducer must assemble earlier.The transducer that meets this specification may have to be dropped or return adjustment or repairing then.
The purpose of this invention is to provide a kind of capacitive transducer and be used for for example condenser microphone, wherein capacitive transducer has been determined the major parameter of transducer, stage so in early days, that is to say, whole energy transducer is manufactured come out before, the deviation that falls short of specifications that may occur can be detected, and therefore can obtain more economical product.
In this article, term " electrode " is meant a kind of conducting element, comprises the device that can be used to carry electrode.
Two electrodes can all be movably, perhaps all fix, perhaps one be fix and another is movably.
In a preferred embodiment, first electrode is fixed, and second electrode is movably.
In a preferred embodiment, strutting piece that assembles and electrode form the space of a sealing, and this space comprises air.
In this article, term " space of sealing comprises air " is meant that the air that is included between strutting piece and the electrode can be or also can not seal.
When strutting piece comprises a body of determining an axial cylindrical tubular, this body has inner surface and outer surface, first axle head and second axle head are arranged, fixed electrode is fixed on the inner surface of the body that is positioned at or closes on first axle head, travelling electrode is assemblied in second axle head of body along its neighboring, and, guarantee to provide a kind of method flexibly that the electrode of transducer is remained on a fixing geometric position mutually like this with predetermined distance and fixed electrode keeping parallelism.
According to the present invention, a capacitive transducer that has two conductive plates is provided, one for example is fixed electrode, another for example is with respect to the fixed electrode removable electrode.This travelling electrode is assemblied in an end of transducer ring-type element, and fixed electrode is placed on the insulator, and this insulator is fixed on the inside of ring-type element, and with travelling electrode clear and definite a bit of distance support fixation electrode is being arranged.
Because two electrodes all are assemblied on the ring-type element or in the ring-type element, so this ring-type element can be embedded in the shell of multiple microphone, do not relate to the whole requirement of stability and environmental sensitivity and do not need to compromise.Compared in the past, and so just allowed more undemanding sum of errors to produce shell with comparatively cheap material.So just have many good qualities.The each several part element of microphone can be produced independently with required accuracy rating, thereby has avoided the needs of individual operations.Compared in the past, selected material of element and geometry no longer are so harsh, because only be to decide its sensitivity and frequency response by this capacitive transducer, and most environmental sensitivity.At last, transducer can be tested function, frequency response and the sensitivity of two basic parameters of this transducer before finally being assembled in the microphone case.Can whether exceed the error allowed band than earlier detecting key parameter originally in process of production like this, or detect the deviation with target component, and defective and mistake.This just causes the greatly thrifty of cost in process of production.This in the past test can only just can be carried out after whole microphone assembling is finished.
Tubular body comprise an outer wall and one by transverse wall near first axial end, be connected to rigidly being roughly of outer wall columniform in the supporting walls element, the sub-fraction that the supporting walls element extends its axial length in being somebody's turn to do on the tubular body axial direction, for fixed electrode constitutes a bearing, guarantee to provide a kind of design easily that fixed electrode (the carrier band element that may comprise it) is embedded in the tubular body like this.In addition, this tubular body also provides a benchmark, and to guarantee a keeping distance constant, that determine between two electrodes, this makes it can repeat to realize in different device.
First electrode comprises an insulation carrier band element that carries conducting element, and this guarantees to provide first electrode is fixed to method easily on the above-mentioned strutting piece.As substituting of the electrode that is made of part insulation and a part of element that conducts electricity, this electrode can be made by conducting element (such as metal) fully or can be made by the material that electric conducting material and insulating material mix on microcosmic or macroscopic view.
In a preferred embodiment, tubular body and electrode are selected to design according to mechanical structure and material, and stress comprises thermal stress like this, can minimize.
In a preferred embodiment, the cylindrical tubular body of strutting piece is made by electric conducting material.It can be made by insulating material (such as ceramic material) or by insulating material coated with metal material or materials similar, to substitute the material of monolithic conductive.
In a preferred embodiment, fixed electrode and tubular body are complementary, and fixed electrode is fixed on the tubular body of strutting piece by the frictional force between fixed electrode and the tubular body.This method has an advantage, and fixed electrode is installed by the method for pressing, and does not need other fixture.
Perhaps, fixed electrode also can be fixed on the tubular body of strutting piece by gluing method.
In a preferred embodiment, fixed electrode adopts the form of back plate electrode, comprise an electric insulation carrier band material, two opposite has been coated a conductive layer in whole or in part, these layers are electrically connected and connect, and separate with the contact area of back plate electrode and tubular body, it separates mode is the electrical isolation of guaranteeing between back plate electrode and the tubular body.Such advantage is to provide a method repeatably easily, can be mechanically connected on the tubular body easily and easily fixed electrode and other parts is electrically connected, and does not link to each other on guaranteeing fixed electrode simultaneously and tubular body being electric.
When from the one group of material that comprises ceramic material, plastics, glass, ruby, sapphire and quartz, selecting electrical insulating material, guaranteed to provide the material frequency spectrum that accordingly low conductivity is had suitable selection.
When the conductive layer on the electric insulation carrier band material of fixed electrode is when making by silk screen printing, stencilization or gasification process, guaranteed to have selected from standard method the method for a kind of common use in electronic environment, the use of this method provides a kind of not only accurate but also economic method.
When travelling electrode is when being made of metal, metal alloy or metallization insulator, guaranteed to provide a kind of high-quality the transducer barrier film or vibrating membrane of (comprise measuring and use microphone) of being very suitable for.
When being applied in one or two electrodes, guaranteed that these parts are adapted at polarizing in advance to use in the type microphone as the insulator layer of electret.
Fixed electrode comprises an insulator, such as being configured as insulating disc, and the conductive coating that has one deck to make by silk screen printing, stencilization or vaporization technology.This insulator is preferably made by pottery, and forms conductive coating in the one side by silk screen printing or vaporization.This fixed electrode can be coated with the thin rare or similar insulating material of fluorinated ethylene-propylene of last layer, in order in the microphone of polarization type in advance, to use, and the electret build microphone known to just.
When electric insulation carrier band element is when being made by laser cutting or method for drilling holes by a slice ceramic material sheet, it has guaranteed to provide a kind of economic especially method.
When back plate electrode by using method on the opposite side that the conductive layer configuration is applied to a ceramic material sheet by silk screen printing, stencilization or gasification process and make and this configuration forming one and arranges independently back plate electrode array, and when back plate electrode and potsherd being separated by laser cutting or laser drill, it has guaranteed to provide a kind of economic especially method, and this method is particularly suitable for producing on a large scale high-precision transducer.
When strutting piece has a datum plane on respect to the very definite position of second electrode, and first electrode is when this datum plane is assembled on the strutting piece relatively, guaranteed to provide a kind of with fixed electrode with respect to travelling electrode accurately and repeatably assembling.
When this position with respect to the datum plane of travelling electrode was determined by silk screen printing, stencilization or gasification process, it had guaranteed to provide a kind of with fixed electrode very accurate with respect to travelling electrode, and adjust easily and repeatably assembling.
When on the back plate electrode by the silk screen printing configuration determine of not having between the electrode under the operating state predetermined apart from the time, guaranteed to provide a kind of with fixed electrode very accurate with respect to travelling electrode, and adjust easily and repeatably assembling.
The invention provides a kind of transducer, comprise a shell, this shell has an assembly that comprises first and second electrodes that separated by dielectric substance; One has a base wall and is connected to the back chamber of the electric connection terminal of electrode, the present invention further provides this assembly is fixed on device in the shell.When according to claims, first and second electrodes that separate by dielectric substance are with the form setting of capacitive transducer, and this capacitive transducer is when being fit to be assemblied in the shell, it is guaranteed to provide and has high-quality transducer, it can be configured to adapt to a lot of different application, have different size and different specific embodiments, and the production very economical of this transducer.
When by forming one or more opening in first electrode, and this electrode fixes, and when making it be suitable for as condenser microphone, it has been guaranteed to provide and is suitable for very much the high-quality microphone measured.
This capacitive or condenser microphone comprises the element of an annular, and a side of this element is equipped with a travelling electrode or vibrating membrane.In the ring-type element the inside, a fixed electrode (back plate electrode known to also being) is assemblied in the place near vibrating membrane.The ring-type element that has vibrating membrane and back plate electrode has constituted a capacitive transducer unit, and this unit can be assemblied in the shell.The ring-type element that has vibrating membrane and back plate electrode has most of functions of whole microphone, and this just can be before whole microphone assembling, and to its essential characteristic, sensitivity and frequency response are tested and characterization.This just means that this microphone ratio is easier to Computer-Assisted Design, Manufacture And Test, simultaneously can be with very low cost processing.In addition, microphone of the present invention also depends on the ring-type element that has vibrating membrane and back plate electrode significantly to the sensitivity of environmental change, compare with the microphone (its each several part must be selected meticulously) of prior art, the material of sheathing material, inner chamber and base wall is selected to become not to be very harsh.
After shell was shaped, it had highly reduced to minimum, and this is highly mainly by the height decision perpendicular to the capacitive transducer on the electrode direction, and the area of base wall is bigger than the area of second electrode, and it has guaranteed to provide a very flat microphone.
Base wall is useful on the device that keeps chamber, back and its ambient pressure balance, and base wall comprises a body, this body has one and the contacted smooth in essence surf zone in chamber, back, be used for pressure balanced device and comprise a geometrical configuration that extends from body surface, this configuration overlaps mutually with contact area in such a way, promptly when rear wall is connected with the chamber, back, between chamber, back and its external world, have an opening at least, guaranteed to provide a very repeatably accurate method to control the low frequency cut-off points of transducer like this.This configuration can produce by some standardized means, such as silk screen printing and/or laser cutting or boring, on production and economic point of view, has very big advantage.
The present invention further provides a kind of transducer system, this system comprises that one has the shell of first and second electrodes that separated by dielectric substance, a back chamber that has a base wall and be connected to the electric connection terminal of electrode.When comprising according to a capacitive transducer of the present invention, and when this capacitive transducer was suitable for being assemblied in the shell together with amplifier and electrical interface unit, it had guaranteed to provide a kind of system that can be suitable for different size and specific embodiment of economy.
The shell of transducer can be made into than being easier to integrated electric amplifier or other electron component, and the whole requirement about stability, linear property and environmental sensitivity of not needing to compromise.Compare with prior art, this is possible, because vibrating membrane and back plate electrode are assembled in the ring-type element that is independent of shell, therefore makes the housing designs of transducer require much lower than in the past.This can be configured as the shell of transducer, makes amplifier to be incorporated in the microphone easily, and does not need to increase the cost of transducer enclosure.Use existing technology, the integration of amplifier also is fine, but this means the body of a complexity, and it is more complicated that transducer enclosure becomes, and consequently cost is higher.
The advantage of capacitive transducer of the present invention can be summarized as follows:
● transducer can be than assembling more easily in the past.
● can before finally being assembled in the shell, identify the key property of transducer, can reduce cost like this.
● capacitive transducer comprises a ring-type element that has vibrating membrane and back plate electrode, and this manufacturing that just makes transducer enclosure is to the requirement of scale error and relatively low to the requirement of material.
● transducer enclosure of the present invention is thinner than existing transducer enclosure, and this just makes it can can't satisfy the occasion use of the requirement of size at existing transducer.
● replace the body of original more complicated, transducer of the present invention can manufacture has fairly simple body, and it can independently be produced, and cost is very low.For instance, the microphone case of prior art is very complicated and production cost is high.The present invention replaces this complicated body with a simple shell and chamber, a simple back, and this makes its production cost very low.
● the integration of amplifier or other electron component also can realize on the basis that does not significantly increase the transducer enclosure cost.
The accompanying drawing summary
Next by a preferred embodiment with will be described in more detail the present invention with reference to the accompanying drawings, wherein:
Fig. 1 has shown the condenser microphone of prior art,
Fig. 2 has shown the decomposition diagram of a condenser microphone of capacitive transducer used according to the invention,
Fig. 3 has shown the cross section decomposition view according to a capacitive transducer of the present invention,
Fig. 3 A has shown the capacitive transducer that assembles as shown in Figure 3,
Fig. 4 shown microphone base wall and inner chamber spare decomposition view and
Fig. 5 a and 5b have shown that the another kind of capacitive transducer of the present invention in condenser microphone uses.
These figure are schematically, and simplification is arranged slightly in order to know, they just show for understanding the present invention some essential details, and some unessential details have been omitted.In following whole description process, use identical reference number for same or corresponding part.
Detailed Description Of The Invention
Fig. 2 has shown the decomposition diagram that uses according to a condenser microphone of capacitive transducer of the present invention, Fig. 3,3A and 4 has shown details wherein, wherein Fig. 3 and 3A have shown the capacitive transducer that is used for condenser microphone, and Fig. 4 has shown the decomposition view of the inner chamber spare of microphone base wall shown in Fig. 2 and microphone.
Microphone 100 (Fig. 2) comprises a capacitive transducer 1 (Fig. 3 and 3A).This capacitive transducer 1 comprises a ring-type element 12, and this ring-type element 12 has a base wall 13 and two upright concentric annular wall, and one section distance is radially arranged between this annular wall.Annular wall supports vibrating membrane 11.The free end of inner annular wall is recessed and be lower than the free end 15 of annular wall, holds fixed electrode in this annular wall, also is called back plate electrode 17.Ring-type element 12, back plate electrode 17 and vibrating membrane 11 have constituted capacitive transducer 1 together.
Ring-type element 12 is cylindrical bodies of the conduction that is made of metal.Inner annular wall 16 is sizings like this, and when back plate electrode 17 embedded, this wall can expand, and the frictional force between the outer surface of inner surface that back plate electrode 17 just can be by supporting walls element 16 and back plate electrode 17 fixes in place like this.
Beyond the periphery of vibrating membrane 11, ring-type element 12 has a Free Surface 14, as datum plane, ring-type element 12 can accurately be assembled on the corresponding base directrix plane 23 in the microphone case 21.Corresponding base directrix plane 23 in the datum plane 14 of this ring-type element 12 and the microphone case is match surfaces, and plane preferably, but should also can be slight taper shape in the surface, and the transducer among Fig. 3 A will be positioned at the center of microphone case 21 like this.
Ring-type element 12 has a upright annular wall, and its end face 15 is used for assembling vibrating membrane 11.There is the outward flange of a rounding on the surface 15 of ring-type element 12, and this surface 15 also is intended for the datum plane of assembling back plate electrode 17 in ring-type element 12.In assembling process, it is important to make the distance that accurately keeps one section expectation between back plate electrode 17 and the vibrating membrane 11.This realizes as datum plane by using surface 15.Use suitable device, the precision that such assembling can realize is ± 1 μ m, and is perhaps better.Bring in it is assembled in the ring-type element 12 by back plate electrode 17 being pressed into any one of annular wall 16, this annular wall is a sizing like this, in the back plate electrode process of press in, this wall can expand, back plate electrode just can be secured in the annular wall by frictional force like this, do not make its distortion when perhaps back plate electrode is embedded in the annular wall 16, this back plate electrode can be fixed in the annular wall it by bonding or other fixing means.
Coating on the back plate electrode two sides be by one in back plate electrode 17 vertical electric guide hole 18 or make it keep mutually being electrically connected by one or more through hole 24.Coating does not arrive the edge of insulation disk, has set up appropriate insulation like this between the vibrating membrane 11 on conductive layer on the back plate electrode 19 and the ring-type element 12.Another kind method is that back plate electrode 17 can be a rosette, at its edge electrical insulating material is arranged, and sets up insulating barrier between rosette and ring-type element.
In order to obtain best long-time stability, vibrating membrane 11 by use such as laser beam be welded to or soldering to the surface 15 of ring-type element 12.Before welding, vibrating membrane 11 is stretched over desired correct tension force such as the sensitivity that obtains expectation and frequency response.As shown in Figure 3A, on capacitive transducer, the back side of back plate electrode 17, promptly the surface of vibrating membrane and particularly its conductive layer can directly touch dorsad.
As described in Figure 2, after vibrating membrane 11 and back plate electrode 17 assembled, ring-type element 12 was embedded in the microphone case 21, can accurately ring-type element be assembled on the datum plane 23 of microphone case by datum plane 14.After this, inner chamber spare 31 is embedded in the microphone case 21, and an end 13 of one end and ring-type element is contacted.By internal diameter and/or length and increase that increases or reduce shell or internal diameter and/or the length that reduces inner chamber spare 31, the size in the space, back chamber of microphone can be adjusted.Follow inner chamber piece 31, the microphone case base wall 41 that electrical insulating material is made is embedded into, and this base wall also has the pressure equalisation passage 42 with good vapour lock control.A conductive body 43 such as what be made of metal, is embedded in by an opening in the base wall 41 of microphone case, and body 43 is designed to after the parts quilt assembling correctly in the presence of all, and it will contact with the back side of back plate electrode 17 is electric.This just allows the signal of telecommunication to pass insulative base wall 41 transmission of microphone case from back plate electrode 17.In addition, base wall 41 and inner chamber spare 31 have determined the capacity of back chamber together.By using ring body 51, ring-type element 12, capacity spare 31 and the microphone case base wall 41 that will have vibrating membrane 11 and back plate electrode 17 are fixed in the microphone case.This can be by fixing such as threaded fittings or spring as shown in Figure 2.The accurate realization of ring body is little to the performance impact of microphone, does not therefore show in detail.
According to the present invention, Fig. 5 a and 5b have shown the another kind of condenser microphone that uses capacitive transducer.
Fig. 5 a has shown full view, and Fig. 5 b has shown the feature of the mid portion of the microphone among Fig. 5 a.
Condenser microphone described in Fig. 5 a and the 5b has utilized the transducer 1 shown in Fig. 3 A has been embedded into all possibilities of different microphone case of its shape and any existing measurement microphone, relates to the whole requirement of stability and environmental sensitivity and needn't compromise.Similar embodiment shown in Figure 2, transducer 1 is embedded in the microphone case 21.Yet microphone case 21 is shaped like this, and promptly its whole height has been reduced to minimum, and this whole height is mainly determined by the thickness of back plate electrode 17 and ring-type element 12.Protective cover 45 can be used for protecting (particularly) vibrating membrane 11.By increasing or reduce the internal diameter and/or the length of shell, the size in the space, back chamber of microphone can be adjusted.
The base wall 41 of microphone case can be considered to make with integral body as before, and just in the present embodiment, the diameter of the base wall 41 of microphone case is bigger than vibrating membrane 11.
In the use of present embodiment, ring-type element 12 has one or more the opening that radially extends on the close outer cylindrical wall of base wall 13.When microphone is assembled, the space of a sealing that forms later at vibrating membrane will comprise the space outside the ring-type element 12, and wherein this space is defined by shell 21 and base wall 41.
Compare with prior art, this embodiment is feasible, because ring-type element 12 can be dwindled axially the size that makes progress with the footpath pari passu, can be utilized by the opening that ring-type element 12 outer air containments extend diametrically simultaneously.
Described embodiment has very significant effects to following field, and this field only allows to use very thin transducer on actual size, and its measurement simultaneously must equally with common measurement microphone have very high precision and stability again.
The surface 14 that Fig. 3 and 3A show is sunken with respect to the surface 15 of supporting vibrating membrane 11.
Capacitive transducer in Fig. 3 A is arranged in the cylindrical microphone case 21 of Fig. 2 or is arranged in the tabular shell 21 of major diameter of Fig. 5 B and 5A, when simultaneously its datum plane 14 reclines separately the corresponding datum plane 23 of microphone case, vibrating membrane 11 will flush with the microphone case front end, especially, so just not having to form with this vibrating membrane is the cavity of bottom.Because such cavity can influence the acoustical behavior of microphone inevitably, therefore do not expect to have such cavity.
Yet and the vibrating membrane that the microphone case front end flushes is impaired easily, and therefore expectation is with the sub-fraction distance of this vibrating membrane with respect to the preceding concave end millimeter of microphone case, such as 20-100 μ m.The thickness at the edge that this datum plane 23 that supports the height of upstanding wall 15 of vibrating membrane and microphone case by suitable setting extends internally can reach at an easy rate.
The microphone of polarization type in advance is a kind of condenser microphone of special type, also the electret build microphone known to promptly.Such microphone contains the material of polarization in advance, and this material can be stored permanent electric charge, is used to provide the necessary electric field of microphone work.This material that polarizes in advance is a kind of insulating material, normally a thin sheet of plastics material.In the present invention, before fixed electrode or back plate electrode are mounted in the ring-type element 12, this material that polarizes in advance will be placed on fixed electrode or the back plate electrode 17.
One comprises with the system of similar microphone, a preamplifier and other possible electronic component shown in Figure 2 and can be combined at an easy rate.
Described some preferred embodiments before this, what still should emphasize is that the present invention is not limited to these embodiment, and it can otherwise be implemented in the defined subject area of following claims.Such as, plate electrode described in the alternate figures and back plate electrode, these parts can be any shapes easily, such as hyperbola, parabola shaped, vaulted, perhaps can be the shapes that contains ladder or elbow.
Claims (24)
1. capacitive transducer (1) comprising:
● determine the ring-type element (12) of an axis, this ring-type element (12) has an annular wall (15) and an inner annular wall (16) that is connected to annular wall (15) rigidly, and this inner annular wall (15) has an opening,
● vibrating membrane (11), the annular wall (15) that is fixed on ring-type element (12) goes up and covers this opening, and this vibrating membrane (11) has outward flange and current-carrying part, and this vibrating membrane and its current-carrying part can move according to acoustic pressure,
● disc type device (17), be fixed in the opening of inner annular wall (16) and parallel with vibrating membrane (11), this disc type device (17) have the first surface that contains current-carrying part (19) and with the first surface opposing second surface, this second surface has and the first surface of disc type device (17) on current-carrying part (19) keep the contact element be electrically connected, current-carrying part (19) on the first surface of this disc type device (17) and ring-type element (12) keep a segment distance and with predetermined distance towards vibrating membrane (11), wherein vibrating membrane (11) and the current-carrying part (19) that is positioned on the disc type device (17) have formed a capacitor, and it is characterized in that: the second surface of disc type device (17) directly can contact with contact element.
2. transducer according to claim 1 is characterized in that: beyond the outward flange of vibrating membrane (11), this ring-type element (12) has the Free Surface (14) of the axis direction horizontal expansion of relative ring-type element (12).
3. according to any one the described transducer among the claim 1-2, it is characterized in that: this transducer comprises a shell (21) and a base wall (41), this shell and vibrating membrane (11) define the space of a base closed together, and this shell have one with disc type device (17) on being electrically connected of can contacting from the outside of current-carrying part (19).
4. transducer according to claim 3 is characterized in that: the space of this base closed enlarges by the one or more openings that radially extend in the ring-type element (12).
5. transducer according to claim 1 is characterized in that: ring-type element (12) is made by electric conducting material.
6. transducer according to claim 1 is characterized in that: disc type device (17) is fixed in the ring-type element (12) by frictional force.
7. transducer according to claim 1, it is characterized in that: disc type device (17) comprises the insulating material (20) that has current-carrying part (19), and this insulating material is selected from the one group of material that comprises ceramic material, plastics, ruby, sapphire and quartz.
8. transducer according to claim 7 is characterized in that: this insulating material is Al
2O
3
9. transducer according to claim 1, it is characterized in that: one in advance material to the small part of polarization cover on the first surface of disc type device (17) or cover vibrating membrane (11) on the surface of disc type device (17), perhaps above-mentioned two surfaces all cover.
10. transducer according to claim 2 is characterized in that: the Free Surface (14) of the axis direction horizontal expansion of this relative ring-type element (12) caves in respect to vibrating membrane (11).
11. transducer according to claim 3, it is characterized in that described shell (21) is an annular or tube element, have a first surface that reclines mutually with the Free Surface (14) of ring-type element, with the front surface parallel and relative with first surface with vibrating membrane (11), vibrating membrane (11) caves in 20 μ m to 100 μ m with respect to this front surface.
12. transducer according to claim 3, it is characterized in that: described shell (21) is annular or tube element, have a first surface that reclines mutually with the Free Surface (14) of ring-type element, with the front surface parallel and relative with first surface with vibrating membrane (11), vibrating membrane (11) and front surface flush substantially.
13. capacitive transducer (1) comprising:
● determine a ring-type element axis and that have opening (12),
● vibrating membrane (11), be fixed on ring-type element (12) and go up and cover this opening, this vibrating membrane (11) has outward flange and current-carrying part, and this vibrating membrane and its current-carrying part can move according to acoustic pressure,
● disc type device (17), be fixed in the described opening of ring-type element (12) and parallel with vibrating membrane (11), this disc type device (17) have the first surface that contains current-carrying part (19) and with the first surface opposing second surface, this second surface has and the first surface of disc type device (17) on current-carrying part (19) keep the contact element be electrically connected, current-carrying part (19) on the first surface of this disc type device (17) and ring-type element (12) keep a segment distance and with predetermined distance towards vibrating membrane (11), wherein vibrating membrane (11) and the current-carrying part (19) that is positioned on the disc type device (17) have formed a capacitor, it is characterized in that: in the outward flange outside of vibrating membrane (11), ring-type element (12) has the Free Surface (14) of the axis direction horizontal expansion of a relative ring-type element (12).
14. transducer according to claim 13 is characterized in that: the second surface of disc type device (17) directly can contact with contact element.
15. according to any one the described transducer among the claim 13-14, it is characterized in that: this transducer comprises a shell (21) and a base wall (41), this shell and vibrating membrane (11) define the space of a base closed together, and this shell have one with disc type device (17) on being electrically connected of can contacting from the outside of current-carrying part (19).
16. transducer according to claim 15 is characterized in that: the space of this base closed enlarges by the one or more openings that radially extend in the ring-type element (12).
17. transducer according to claim 13 is characterized in that: ring-type element (12) is made by electric conducting material.
18. transducer according to claim 13 is characterized in that: disc type device (17) is fixed in the ring-type element (12) by frictional force.
19. transducer according to claim 13, it is characterized in that: disc type device (17) comprises the insulating material (20) that has current-carrying part (19), and this insulating material is selected from the one group of material that comprises ceramic material, plastics, ruby, sapphire and quartz.
20. transducer according to claim 19 is characterized in that: this insulating material is Al
2O
3
21. transducer according to claim 13, it is characterized in that: one in advance material to the small part of polarization cover on the first surface of disc type device (17) or cover vibrating membrane (11) on the surface of disc type device (17), perhaps above-mentioned two surfaces all cover.
22. transducer according to claim 13 is characterized in that: the Free Surface (14) of the axis direction horizontal expansion of this relative ring-type element (12) caves in respect to vibrating membrane (11).
23. transducer according to claim 15, it is characterized in that described shell (21) is an annular or tube element, have a first surface that reclines mutually with the Free Surface (14) of ring-type element, with the front surface parallel and relative with first surface with vibrating membrane (11), vibrating membrane (11) caves in 20 μ m to 100 μ m with respect to this front surface.
24. transducer according to claim 15, it is characterized in that: described shell (21) is annular or tube element, have a first surface that reclines mutually with the Free Surface (14) of ring-type element, with the front surface parallel and relative with first surface with vibrating membrane (11), vibrating membrane (11) and front surface flush substantially.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DKPA200001567 | 2000-10-20 | ||
| DKPA200001567 | 2000-10-20 | ||
| US24567200P | 2000-11-06 | 2000-11-06 | |
| US60/245,672 | 2000-11-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1481654A CN1481654A (en) | 2004-03-10 |
| CN1284414C true CN1284414C (en) | 2006-11-08 |
Family
ID=26068899
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB018206239A Expired - Lifetime CN1284414C (en) | 2000-10-20 | 2001-10-19 | Capacitive transducer |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP1329129B1 (en) |
| CN (1) | CN1284414C (en) |
| AU (1) | AU2002210400A1 (en) |
| DE (2) | DE60109953T2 (en) |
| WO (1) | WO2002034008A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102026076A (en) * | 2009-09-11 | 2011-04-20 | 台湾驻极体电子股份有限公司 | Solar electret transducer and low-energy consumption electret transducer |
| US9967677B2 (en) * | 2015-12-04 | 2018-05-08 | Infineon Technologies Ag | System and method for sensor-supported microphone |
| CN108696808B (en) * | 2018-08-02 | 2020-11-17 | 歌尔股份有限公司 | Loudspeaker and loudspeaker assembling method |
| TWI692255B (en) * | 2018-10-30 | 2020-04-21 | 美律實業股份有限公司 | MEMS sensor |
| CN110677798A (en) * | 2019-09-09 | 2020-01-10 | 国网湖南省电力有限公司 | Microphone with self-calibration function, calibration method thereof, sound transmission system and sound detection system |
| DE102022114073A1 (en) | 2022-06-03 | 2023-12-14 | Sennheiser Electronic Gmbh & Co. Kg | Electret microphone |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3588382A (en) * | 1967-10-11 | 1971-06-28 | Northern Electric Co | Directional electret transducer |
| NL7313455A (en) * | 1973-10-01 | 1975-04-03 | Philips Nv | MICROPHONE WITH ELECTROSTATIC CAPSULE. |
| FR2412297A2 (en) * | 1977-01-25 | 1979-07-20 | Anvar | NEW RESPIRATION MONITORING DEVICES |
| GB2029161B (en) * | 1978-08-21 | 1983-01-26 | Hosiden Electronics Co | Electret microphone |
| US4443666A (en) * | 1980-11-24 | 1984-04-17 | Gentex Corporation | Electret microphone assembly |
| DK146770C (en) * | 1981-11-13 | 1984-06-04 | Brueel & Kjaer As | CAPACITY TRANSDUCER |
| NL1002880C2 (en) * | 1996-04-16 | 1997-10-17 | Microtronic Nederland Bv | Electroacoustic transducer. |
| US5854846A (en) * | 1996-09-06 | 1998-12-29 | Northrop Grumman Corporation | Wafer fabricated electroacoustic transducer |
-
2001
- 2001-10-19 EP EP01978227A patent/EP1329129B1/en not_active Expired - Lifetime
- 2001-10-19 DE DE60109953T patent/DE60109953T2/en not_active Expired - Lifetime
- 2001-10-19 CN CNB018206239A patent/CN1284414C/en not_active Expired - Lifetime
- 2001-10-19 DE DE60107876T patent/DE60107876T2/en not_active Expired - Lifetime
- 2001-10-19 WO PCT/DK2001/000692 patent/WO2002034008A1/en active IP Right Grant
- 2001-10-19 AU AU2002210400A patent/AU2002210400A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| DE60109953D1 (en) | 2005-05-12 |
| DE60107876T2 (en) | 2005-12-22 |
| EP1329129B1 (en) | 2005-04-06 |
| AU2002210400A1 (en) | 2002-04-29 |
| EP1329129A1 (en) | 2003-07-23 |
| DE60109953T2 (en) | 2006-02-09 |
| DE60107876D1 (en) | 2005-01-20 |
| CN1481654A (en) | 2004-03-10 |
| WO2002034008A1 (en) | 2002-04-25 |
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