CN205830021U - A kind of micro-electro-mechanical microphone - Google Patents
A kind of micro-electro-mechanical microphone Download PDFInfo
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- CN205830021U CN205830021U CN201620783466.8U CN201620783466U CN205830021U CN 205830021 U CN205830021 U CN 205830021U CN 201620783466 U CN201620783466 U CN 201620783466U CN 205830021 U CN205830021 U CN 205830021U
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- fixed polar
- plate
- polar plate
- transaudient
- lower fixed
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Abstract
The utility model discloses a kind of micro-electro-mechanical microphone; using U-shaped cavity volume as containment vessel; the transaudient entrance of one-level, two grades of transaudient entrances, division board, upper fixed polar plate, lower fixed polar plates are set gradually from top to bottom inside cavity volume; wherein the transaudient entrance of one-level is arranged at U-shaped cavity volume edge topmost; every side that division board is symmetrical below bilateral symmetry, and division board is respectively provided with about one group corresponding upper fixed polar plate, lower fixed polar plate；Vibration sensing plate is arranged at the inside of cavity volume, and vibration sensing plate be shaped as I shape, the entablature of I shape is positioned in the middle of two grades of transaudient entrances and division board, and the sill of I shape is positioned at the centre of fixed polar plate and lower fixed polar plate；Lower fixed polar plate is connected with the input of pre-amplifier module in testing circuit, and makes lower fixed polar plate virtual earth.This utility model micro-electro-mechanical microphone has a feature of high sensitivity, low noise, low cost of manufacture and practical.
Description
Technical field
This utility model relates to loudspeaker techniques field, particularly a kind of micro-electro-mechanical microphone.
Background technology
At present, conventional microphone still suffers from that volume is big, sensitivity is low, noise is big etc. and is difficult to the defect overcome.Along with microcomputer
The microminiaturization of breakthrough and the integrated circuit of electricity manufacturing technology, volume is little, lightweight and easy and IC collection because having for micro-electro-mechanical microphone
The outstanding advantages such as one-tenth were once becoming main flow and the focus of research, and occupied leading position in mike field.Existing condenser type
Mike has certain advantage in terms of the key property such as the flatness of frequency response and noise and stability, but in spirit
Sensitivity aspect is difficult to break through always.At present, common Electret Condencer Microphone sensitivity is less than 9Mv/Pa.
Electret Condencer Microphone frequently with typical structure have single-chip and double-chip structure.Consider into production. art etc., single
The processing technology of the micromachined microphones that silicon chip is integrated is simpler than double wafer bonding formula micromachined microphones, has more industrialization
Prospect.But it is less susceptible to control internal stress in its sensitive membrane during making single-chip mike.For release micromechanics wheat
This technical barrier of internal stress on Clofazimine sense film, scholars devise the sensitive membrane of various structures, have such as opened in release
The structure in stress hole, or carry fluted circular sensitive membrane etc..So, although micromachined microphones can reduce sensitive membrane
On internal stress, but owing to the structure of sensitive membrane and the manufacturing process of minute yardstick are complicated, be unfavorable for industrial mass manufacture.
Utility model content
The purpose of this utility model is to provide the micro-electro-mechanical microphone of a kind of high sensitivity, high bandwidth, low cost.
The technical solution realizing this utility model purpose is: a kind of micro-electro-mechanical microphone, using U-shaped cavity volume as guarantor
Protective case, sets gradually the transaudient entrance of one-level, two grades of transaudient entrances, division board, upper fixed polar plate, lower solid from top to bottom inside cavity volume
Fixed plate, wherein the transaudient entrance of one-level is arranged at U-shaped cavity volume edge topmost, and division board is bilateral symmetry, and isolation
Every side symmetrical below plate is respectively provided with about one group corresponding upper fixed polar plate, lower fixed polar plate；Vibration sensing plate is arranged at
The inside of cavity volume, and vibration sensing plate be shaped as I shape, the entablature of I shape is positioned at two grades of transaudient entrances and division board
Centre, the sill of I shape is positioned at the centre of fixed polar plate and lower fixed polar plate；Before in lower fixed polar plate and testing circuit
The input putting amplifier module is connected, and makes lower fixed polar plate virtual earth；
Sound is by conducting to vibration sensing plate, vibration sensing plate edge after the transaudient entrance of one-level and two grades of transaudient ingress filterings
Fixed-direction to be subjected to displacement, adjust vibration sensing plate by the entablature and sill spacing changing I shape fixing with upper
Pole plate, the equilbrium position of lower fixed polar plate, the displacement between vibration sensing plate sill and upper fixed polar plate and lower fixed polar plate
Change is converted into differential capacitance change, becomes current signal by the bias voltage of pre-add, then is amplified by preamplifier,
It is eventually transformed into voltage signal output.
Further, the transaudient entrance of described one-level and two grades of transaudient entrances are the square through-hole of same size, and two-stage passes
Sound entrance intersects and is staggered distribution, and the transaudient entrance in every grade is equidistantly uniformly distributed, the transaudient entry level of one-level and two grades transaudient
Distance between entry level is less than 5mm.
Further, described vibration sensing plate is the THIN COMPOSITE using silica membrane and silicon nitride film to be compounded to form
Film, vibration sensing plate is symmetrical I-shaped structure, and the entablature of I shape and sill spacing are 15mm.
Further, differential parallel of the sill of described vibration sensing plate and upper fixed polar plate, lower fixed polar plate composition
Plate electric capacity.
Further, described pre-amplifier module is made up of integrated operational amplifier, the anti-phase input of operational amplifier
End be connected with lower fixed polar plate, in-phase input end ground connection, between inverting input and amplifier out distinguish parallel resistance and
Electric capacity.
Compared with prior art, its remarkable advantage is the present invention: multistage through hole on (1) mike entering tone mouth, can effectively decline
Subtract the interference strength of noise contribution, improve the signal to noise ratio of mike, keep the pure degree of sound；(2) complex vibration sensitive membrane knot
Structure is simple to manufacture, and can eliminate the residual tension within original sensitive membrane, improves the sensitivity behaviour of mike；(3) use
Symmetrical input, the mode of differential detection, small-signal can be amplified, improve detection range, improve sensitivity further, it is possible to
The Nonlinear perturbations amounts such as elimination system constant error.
Accompanying drawing explanation
Fig. 1 is the signal flow path switch figure of this utility model micro-electro-mechanical microphone.
Fig. 2 is the structure chart of this utility model micro-electro-mechanical microphone.
Fig. 3 is the local parameter enlarged drawing of this utility model micro-electro-mechanical microphone.
Fig. 4 is the preamplifier circuit figure of this utility model micro-electro-mechanical microphone.
Detailed description of the invention
Below in conjunction with the accompanying drawings this utility model is described in further detail.
This utility model micro-electro-mechanical microphone, is used primarily on the personal electric product such as mobile phone or notebook computer, uses
Acoustical signal transferring to the signal of telecommunication and processes identification for master chip, signal conversion process is as it is shown in figure 1, thus improve existing product
Performance indications etc..
In conjunction with Fig. 2, this utility model micro-electro-mechanical microphone, using U-shaped cavity volume 1 as containment vessel, cavity volume 1 is internal from up to
Under set gradually the transaudient entrance of one-level 6, two grades of transaudient entrances 7, division board 3, upper fixed polar plate 4, lower fixed polar plates 5, Qi Zhongyi
The transaudient entrance 6 of level is arranged at U-shaped cavity volume 1 edge topmost, and division board 3 is symmetrical below bilateral symmetry, and division board 3
Every side be respectively provided with about one group corresponding upper fixed polar plate 4, lower fixed polar plate 5；Vibration sensing plate 2 is arranged at cavity volume 1
Inside, and vibration sensing plate 2 be shaped as " work ", the entablature of " work " font be positioned at two grades of transaudient entrances 7 with in division board 3
Between, the sill of " work " font is positioned at the centre of fixed polar plate 4 and lower fixed polar plate 5；In lower fixed polar plate 6 and testing circuit
The input of pre-amplifier module is connected, and makes lower fixed polar plate 6 virtual earth；
Sound is conducted to vibration sensing plate 2, vibration sensing after being filtered by the transaudient entrance of one-level 6 and two grades of transaudient entrances 7
Plate 2 is subjected to displacement along fixed-direction, by entablature and the sill spacing changing I shape adjust vibration sensing plate 2 with
Upper fixed polar plate 4, the equilbrium position of lower fixed polar plate 5, vibration sensing plate 2 sill and upper fixed polar plate 4 and lower fixed polar plate 6
Between change in displacement be converted into differential capacitance change, become current signal by the bias voltage of pre-add, then by preposition
Amplifier amplifies, and is eventually transformed into voltage signal output.So, the most just realize Differential Detection, amplify variable quantity, improve sensitive
The purpose of degree.
Further, cavity volume 1 should be fixed on product, possesses rigidity big, is not susceptible to deformation and the feature of shake.
Further, the transaudient entrance of described one-level 6 and two grades of transaudient entrances 7 are the square through-hole of same size, two-stage
Transaudient entrance intersects and is staggered distribution, and the transaudient entrance in every grade is equidistantly uniformly distributed, and aperture is followed in the parameter selection of through hole
Little and principle that hole count is many, the noise intensity that effective attenuation is faint, play the function reducing noise.The transaudient entry level of one-level and two
Distance between the transaudient entry level of level is less than 5mm.
Further, described vibration sensing plate 2 is compound for use silica membrane and silicon nitride film to be compounded to form
Thin film, vibration sensing plate 2 is symmetrical I-shaped structure, and the entablature of I shape and sill spacing are 15mm.Utilize stress
The compressive stress of silica membrane and the tensile stress of silicon nitride film are compounded to form laminated film by balancing technique, reach lower
Thermal capacitance and thermal conductivity coefficient, reduce the factor such as the residual tension impact of vibration sensing plate 2.Vibration sensing plate 2 is put for symmetrical
Put in cavity volume 1, be in the initial state equilbrium position of fixed polar plate 4, lower fixed polar plate 5.Division board 3 damping that is limited moves sensitive plate
The shift length of 2, its position determines microphone voice detection range.Division board 3 keeps with the edge of vibration sensing plate 2 axis
Closely cooperate, gapless.
Further, the sill of described vibration sensing plate 2 and upper fixed polar plate 4, lower fixed polar plate 5 form differential putting down
Andante electric capacity.Fixed polar plate 4 is identical with the structural parameters of lower fixed polar plate 5, is formed differential parallel with vibration sensing plate 2
Plate electric capacity.When vibration sensing plate 2 deviation upper fixed polar plate 4, lower fixed polar plate 5 equilbrium position, by detecting its differential electricity
Hold variable quantity and obtain acoustical signal characteristic.By loading a bias voltage to parallel plate capacitor, capacitance change is made to be converted into
Current change quantity, then by amplifying circuit, current signal is changed into voltage signal output for subsequent conditioning circuit conditioning process.
Further, described pre-amplifier module is made up of integrated operational amplifier, the anti-phase input of operational amplifier
End be connected with lower fixed polar plate 6, in-phase input end ground connection, between inverting input and amplifier out distinguish parallel resistance and
Electric capacity.In addition to the transaudient entrance of one-level 6 and two grades of transaudient entrances 7, this apparatus structure should be ensured that symmetrical, i.e. forms two
Differential detection capacitive part, improves sensitivity further.
Embodiment 1
The method that this utility model mike detection sound is adopted as becoming spacing Differential Detection sound.As in figure 2 it is shown, sound
After multistage filtering by the transaudient entrance 7 of the transaudient entrance of one-level 6 and two grades, reach vibration sensing plate 2, vibration sensing plate 2 along
Fixed-direction is subjected to displacement, and breaks itself and upper fixed polar plate 4, the balance position of lower fixed polar plate 5 by changing capacitor board spacing
Put, it is achieved Differential Input testing goal, amplify variable quantity.
Transaudient entrance at different levels between intersect and be staggered distribution, at different levels within be equidistantly uniformly distributed, described hole is most preferably selected
Being selected as square through-hole, a size of 2mm × 2mm but it also may select circular port, the form such as slot, the parameter in hole selects
The principle that hole count is many for aperture is little.
Vibration sensing plate 2 selects the I-shaped structure of symmetry, and the width of both wings up and down of I shape selects 2mm to be optimal, can
To strengthen mechanical property, reduce stress, improve susceptiveness.Sensitive plate material uses stress equilibrium technology, by silica membrane
Compressive stress and the tensile stress of silicon nitride film be compounded to form laminated film, reduce stress deformation impact further.
Division board 3 edge uses encapsulant, keeps closely cooperating, continuously with the edge of the axis of vibration sensing plate 2
Gap, anti-leak-stopping sound.
Calculate below by parameter and illustrate to detect variable quantity.
As it is shown on figure 3, described tiled configuration parameter is identical, take wherein analytic explanation.If during equilbrium position, on
Lower fixed polar plate is d with the spacing of vibration sensing plate0, overlapping area laterally fixed by fixed polar plate and movable vibration sensing plate
Being S, the internal dielectric constant of mike is ε0.When then setting balance, the electric capacity that upper fixed polar plate is constituted with vibration sensing plate is C10,
The electric capacity that upper fixed polar plate is constituted with vibration sensing plate is C20, its size hasWhen vibration sensing plate is along biography
When the displacement in sound direction is d (t), now going up the electric capacity that fixed polar plate and vibration sensing plate constitute isLower solid
The electric capacity that fixed plate is constituted with vibration sensing plate isThen according to the principle of differential detection, the public affairs of its both-end
End detection variable quantity is altogether:
Described detection limit, compared with existing unipolar plate capacitance change, can detect fainter variable quantity, improves spirit
Sensitivity.Owing to this utility model takes symmetric design, the mode of differential detection, noise or other intrinsic systems can be reduced
The interference factor of error.
As shown in Figure 4, common port difference detecting method taked by described mike, applies reverse voltage signal respectively upper solid
On fixed plate 4, lower fixed polar plate 5, public vibration sensing plate 2 is connected with the input of preamplifier.Preamplifier mould
Block is made up of integrated operational amplifier, and the inverting input of operational amplifier is connected with lower fixed polar plate 5, and in-phase input end connects
GND, difference parallel resistance and parallel plate capacitor between inverting input and amplifier out.So, above-mentioned physics
Amount change order is acoustical signal, displacement signal, capacitance change signal, current signal, is more finally reduced to voltage signal
Output.
This utility model can improve the structure of existing Electret Condencer Microphone on the product such as mobile phone and notebook, to reach to carry
High sensitivity, the problem reducing manufacturing process cost, there is considerable market prospect.
Claims (5)
1. a micro-electro-mechanical microphone, it is characterised in that: using U-shaped cavity volume (1) as containment vessel, cavity volume (1) is internal from up to
Under set gradually the transaudient entrance of one-level (6), two grades of transaudient entrances (7), division board (3), upper fixed polar plate (4), lower fixed polar plates
(5), wherein the transaudient entrance of one-level (6) is arranged at U-shaped cavity volume (1) edge topmost, and division board (3) is bilateral symmetry,
And every side of division board (3) lower section symmetry is respectively provided with about one group corresponding upper fixed polar plate (4), lower fixed polar plate (5)；Shake
Dynamic sensitive plate (2) is arranged at the inside of cavity volume (1), and vibration sensing plate (2) be shaped as I shape, the entablature position of I shape
In the middle of two grades of transaudient entrances (7) with division board (3), the sill of I shape is positioned at fixed polar plate (4) and lower fixed polar plate
(5) centre；Lower fixed polar plate (5) is connected with the input of pre-amplifier module in testing circuit, and makes lower fixed polar plate
(5) virtual earth；
Sound is conducted to vibration sensing plate (2) after being filtered by the transaudient entrance of one-level (6) and two grades of transaudient entrances (7), vibrates quick
Sense plate (2) is subjected to displacement along fixed-direction, adjusts vibration sensing by changing the entablature of I shape with sill spacing
Plate (2) and upper fixed polar plate (4), the equilbrium position of lower fixed polar plate (5), vibration sensing plate (2) sill and upper fixed polar plate
(4) change in displacement and between lower fixed polar plate (5) is converted into differential capacitance change, is become by the bias voltage of pre-add
Current signal, then amplified by preamplifier, it is eventually transformed into voltage signal output.
Micro-electro-mechanical microphone the most according to claim 1, it is characterised in that: the transaudient entrance of described one-level (6) and two grades of biographies
Sound entrance (7) is the square through-hole of same size, and the transaudient entrance of two-stage intersects and is staggered distribution, and the transaudient entrance etc. in every grade
Spacing is uniformly distributed, and the distance between the transaudient entry level of one-level and two grades of transaudient entry level is less than 5mm.
Micro-electro-mechanical microphone the most according to claim 1, it is characterised in that: described vibration sensing plate (2) is for using dioxy
The laminated film that SiClx thin film and silicon nitride film are compounded to form, vibration sensing plate (2) is symmetrical I-shaped structure, I shape
Entablature and sill spacing be 15mm.
Micro-electro-mechanical microphone the most according to claim 1, it is characterised in that: the sill of described vibration sensing plate (2) with
Upper fixed polar plate (4), lower fixed polar plate (5) form differential parallel plate capacitor.
Micro-electro-mechanical microphone the most according to claim 4, it is characterised in that: described pre-amplifier module is by integrated computation
Amplifier forms, and the inverting input of operational amplifier is connected with lower fixed polar plate (5), in-phase input end ground connection, anti-phase input
Difference parallel resistance and electric capacity between end and amplifier out.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620783466.8U CN205830021U (en) | 2016-07-22 | 2016-07-22 | A kind of micro-electro-mechanical microphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620783466.8U CN205830021U (en) | 2016-07-22 | 2016-07-22 | A kind of micro-electro-mechanical microphone |
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| Publication Number | Publication Date |
|---|---|
| CN205830021U true CN205830021U (en) | 2016-12-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620783466.8U Expired - Fee Related CN205830021U (en) | 2016-07-22 | 2016-07-22 | A kind of micro-electro-mechanical microphone |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112492479A (en) * | 2020-12-02 | 2021-03-12 | 潍坊歌尔微电子有限公司 | Miniature microphone dust keeper and MEMS microphone |
-
2016
- 2016-07-22 CN CN201620783466.8U patent/CN205830021U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112492479A (en) * | 2020-12-02 | 2021-03-12 | 潍坊歌尔微电子有限公司 | Miniature microphone dust keeper and MEMS microphone |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20161221 Termination date: 20170722 |