A kind of MEMS microphone
Technical field
This utility model embodiment is related to acoustic-electric conversion art, more particularly, to a kind of MEMS microphone.
Background technology
MEMS (Micro-Electro-Mechanical System Micro Electro Mechanical Systems) mike is based on MEMS technology
The mike of manufacture, acoustic diaphragm therein, back pole plate are the vitals in MEMS microphone, acoustic diaphragm, back pole plate structure
Into " pole plate " of capacity plate antenna, and it is integrated on MEMS chip.
Existing MEMS microphone, as shown in figure 1, including PCB (Printed Circuit Board printed circuit board (PCB)s) plate
1 ', MEMS chip 3 ', ASIC (Application-Specific- are included in the encapsulating structure that shell 2 ' is surrounded, encapsulating structure
Integrated-Circuit special ICs) chip 4 ', wherein, MEMS chip 3 ' and asic chip 4 ' are each attached to PCB
On plate 1 ', electrically connected by gold thread 5 ' between MEMS chip 3 ' and asic chip 4 ' to realize that acoustoelectric signal is changed, asic chip
Electrically connect to be transmitted the signal of telecommunication matched with acoustical signal by gold thread 5 ' between 4 ' and pcb board 1 '.When sound (sound
Pressure) when entering resonance chamber 31 ' by acoustic aperture, there is resonance in acoustic pressure in resonance chamber to signal, the effect that resonance is produced is pushed
When dynamic acoustic diaphragm deforms upon displacement, the deformational displacement of acoustic diaphragm causes the change of distance between capacity plate antenna " pole plate " (i.e.
The capacitance of the plates capacitance of change), such that it is able to the change-detection sound pressure variations according to capacity plate antenna, realize the conversion of acoustic-electric.
When the acoustic pressure for detecting analogue signal is larger, acoustic diaphragm towards acoustic aperture opposite direction deformational displacement power also more
Greatly, when the deformational displacement of acoustic diaphragm reaches maximum, still there is acoustic pressure to promote acoustic diaphragm, and then cause acoustic diaphragm to be in
On the one hand " over loading " deformed state, " over loading " deformation easily cause the elasticity capacity of acoustic diaphragm and decline, and reduce MEMS wheats
The accuracy of gram elegance collection sound, on the other hand when acoustic pressure promotes acoustic diaphragm deformational displacement to exceed acoustic diaphragm deformation maximum pole
In limited time, easily cause the fracture of acoustic diaphragm.
Utility model content
This utility model provides a kind of MEMS microphone, it is intended to limits the Oscillation Amplitude of acoustic diaphragm, prevents acoustic diaphragm
Work in " over loading " deformed state, it is to avoid acoustic diaphragm reduces elasticity capacity because of high sound pressure impact or falling, and significantly improves
The anti-high pressure ability of MEMS microphone, the elasticity capacity of protection acoustic diaphragm.
On the one hand, this utility model embodiment provides a kind of MEMS microphone, wherein:Including
One MEMS chip, the MEMS chip include that a substrate and is arranged at the acoustic diaphragm of the substrate;
Position limiting structure, is arranged along the acoustic diaphragm outer fringe surface, so that the position limiting structure is formed with reference to the substrate
The one spacing cavity for limiting the acoustic diaphragm deformational displacement.
Preferably, above-mentioned MEMS microphone, wherein, the position limiting structure is formed by a pair of limiting plates, the limiting plate
Bottom be fixedly installed on the substrate surface, the top of the acoustic diaphragm is arranged at the top of limiting plate described in a pair with shape
Into the spacing cavity.
Preferably, above-mentioned MEMS microphone, wherein, the position limiting structure is formed by a pair limiting plates of falling embedded, described
The limiting plate of falling embedded is in " Z " font.
Preferably, above-mentioned MEMS microphone, wherein, the limiting plate of falling embedded described in a pair include cylinder, stop tab and
Base plate, the cylinder are respectively perpendicular to the stop tab, the base plate.
Preferably, above-mentioned MEMS microphone, wherein, the logical of the matching cylinder is set on the acoustic diaphragm
The through hole is run through so that the base plate is fixedly installed on the substrate in hole, the cylinder, the limiting plate of falling embedded described in a pair
Stop tab be suspended vacantly above the acoustic diaphragm.
Preferably, above-mentioned MEMS microphone, wherein, the side of the bottom of the acoustic diaphragm towards the substrate direction
It is provided with projection.
Preferably, above-mentioned MEMS microphone, wherein, the projection is anti-grume.
Preferably, above-mentioned MEMS microphone, wherein, the MEMS chip also includes elastic construction, the elastic construction
It is fixedly installed between the acoustic diaphragm and the substrate.
Preferably, above-mentioned MEMS microphone, wherein, also including back pole plate, the back pole plate is fixedly installed on the lining
The precalculated position at bottom, so that the back pole plate forms a capacity plate antenna structure with the acoustic diaphragm.
Compared with prior art, the beneficial effects of the utility model are:
By arranging a position limiting structure along the acoustic diaphragm outer fringe surface, when the deformational displacement of acoustic diaphragm reaches limit
During bit architecture, acoustic diaphragm is contacted with position limiting structure, is passed to beyond the pressure of acoustic diaphragm deformational displacement maximum spacing
Structure, position limiting structure absorb and discharge the acoustic pressure, limit the deformational displacement of acoustic diaphragm, on the one hand prevent acoustic diaphragm from working in
" over loading " deformed state, that is, prevent from reducing the elastic deformation ability of acoustic diaphragm because of " over loading " deformation, it is ensured that MEMS Mikes
The accuracy of elegance collection sound, on the other hand, it is to avoid acoustic diaphragm reduces natural resiliency ability because of high sound pressure impact, significantly improves
The anti-high pressure ability of MEMS microphone, the elasticity capacity of protection acoustic diaphragm.In addition, when MEMS microphone is dropped from high-altitude,
Inside MEMS microphone in addition to acoustic diaphragm, other all elements are fixedly installed on substrate, and MEMS microphone volume phase
To less, even if dropping from high-altitude, cause the probability of other electricity component infringements relatively low, but air drag is in resonance chamber
Resonance further promotes acoustic diaphragm to deform upon displacement, and position limiting structure can effectively prevent air drag from causing to damage to acoustic diaphragm
Evil, improves the drop resistant ability of MEMS microphone.
Description of the drawings
Fig. 1 is the generalized section of MEMS microphone in prior art;
Fig. 2 is the generalized section of the MEMS microphone in this utility model embodiment one;
Fig. 3 is the generalized section of the MEMS microphone in this utility model embodiment two.
Specific embodiment
The utility model is described in further detail with reference to the accompanying drawings and examples.It is understood that herein
Described specific embodiment is used only for explanation this utility model, rather than to restriction of the present utility model.Further need exist for
It is bright, for the ease of description, in accompanying drawing, illustrate only the part related to this utility model rather than entire infrastructure.
Embodiment one
Fig. 2 is a kind of generalized section of MEMS microphone that this utility model embodiment one is provided, wherein:Including
In a first aspect, this utility model embodiment provides a kind of MEMS microphone, wherein:Including
One MEMS chip 1, the MEMS chip 1 include a substrate 11, and one are arranged at the acoustics on the substrate 11
Vibrating diaphragm 12;Further, also include electrode slice 14 on MEMS chip 1, electrode slice 14 is to realize the transmission of the signal of telecommunication.
Position limiting structure 2, is arranged along 12 outer fringe surface of the acoustic diaphragm, so that the position limiting structure 2 combines the substrate
11 form a spacing cavity for limiting 12 deformational displacement of acoustic diaphragm.Further, position limiting structure can be by conductive material
Make, it is also possible to be made up of insulant, be not particularly limited herein.
Operation principle of the present utility model is:
Occur under resonant condition, to produce the gradient that a promotion acoustic diaphragm 12 is deformed upon in resonance chamber in high sound pressure
Pressure, acoustic diaphragm 12 deform upon displacement to the opposite direction of acoustic aperture in the presence of pressure, in the vibration side of acoustic diaphragm 12
To a position limiting structure 2 is arranged, when the Oscillation Amplitude of acoustic diaphragm 12 reaches position limiting structure 2, acoustic diaphragm 12 and position limiting structure 2
Contact, is passed to position limiting structure 2 beyond the pressure of 12 deformational displacement maximum of acoustic diaphragm and is discharged, and limits acoustic diaphragm
12 deformational displacement, on the one hand prevents acoustic diaphragm 12 from working in " over loading " deformed state, that is, prevents because of " over loading " deformation
Reduce the elastic deformation ability of acoustic diaphragm 12, it is ensured that MEMS microphone gathers the accuracy of sound, on the other hand, it is to avoid acoustics
Vibrating diaphragm 12 reduces natural resiliency ability because high sound pressure is impacted, and significantly improves anti-high pressure ability, the protection acoustics of MEMS microphone
The elasticity capacity of vibrating diaphragm 12.In addition, when MEMS microphone is dropped from high-altitude, inside MEMS microphone in addition to acoustic diaphragm 12,
Other all elements are fixedly installed on pcb board, and MEMS microphone volume is relatively small, even and if then high-altitude drop, make
Probability into other electricity component infringements is relatively low, but air drag can further promote acoustic diaphragm 12 to resonance in resonance chamber
Displacement is deformed upon, position limiting structure 2 can effectively prevent air drag from fracture is caused to acoustic diaphragm 12, improve MEMS microphone
Drop resistant ability.
As further preferred embodiment, above-mentioned MEMS microphone, wherein, the position limiting structure 2 is spacing by a pair
Plate shape is into the bottom of the limiting plate is fixedly installed on 11 surface of the substrate, and institute is arranged at the top of limiting plate described in a pair
The direction of vibration of acoustic diaphragm 12 is stated to form the spacing cavity.The top of position limiting structure 2 matches the maximum of MEMS microphone
Bias voltage.
Bias voltage is provided with generally for MEMS microphone, bias voltage is proportional to the deformation position of acoustic diaphragm 12
Move, the deformational displacement distance of acoustic diaphragm 12 determines the detecting accuracy of MEMS microphone.In order to ensure MEMS microphone
Detecting accuracy is constant, in this utility model, the maximum bias voltage of the matched MEMS microphone of position limiting structure 2, i.e. sound
The vibration largest deformation displacement field match maximum bias voltage of vibrating diaphragm 12 is learned, when the deformational displacement of acoustic diaphragm 12 is less than largest deformation
Displacement, can form the bias voltage output for matching the deformational displacement, realize acoustic-electric conversion.When the deformational displacement of acoustic diaphragm 12
More than maximum vibration amplitude, position limiting structure limits the vibration of acoustic diaphragm 12, and bias voltage value is equal to maximum bias voltage, right
In the high pressure beyond maximum vibration amplitude, MEMS microphone does not do precise acquisition.Because the sound point that biological ear can be heard
Generally at 15 to 60 decibels, the sound more than 60 decibels easily damages the auditory nerve of ear to shellfish, and then for more than 60 decibels
High pressure sound, MEMS microphone refuse precise acquisition, only export the bias voltage matched with 60 decibels of acoustic pressures, it is intended to improve
The applied environment of MEMS microphone, for example it is, during MEMS microphone accidentally enters a sound more than 60 decibels of environment, current
Ambient sound does not result in MEMS microphone acoustic diaphragm 12 and damages or rupture.
As further preferred embodiment, above-mentioned MEMS microphone, wherein, the position limiting structure 2 is embedding by a pair
Formula limiting plate is formed, and the limiting plate of falling embedded is in " Z " font.Further, described in a pair, the limiting plate of falling embedded includes cylinder
22nd, stop tab 23 and base plate 21, the cylinder 22 are respectively perpendicular to the stop tab 23, the base plate 21.Stop tab
23 are located above acoustic diaphragm 12, arrange along 12 edge of acoustic diaphragm, and towards acoustic diaphragm 12 centrally along stretching, to effectively anti-
Only acoustic diaphragm 12 " over loading " deformation.
Embodiment two
In above-mentioned technical proposal, stop tab is located above acoustic diaphragm, arranges along acoustic diaphragm edge, and towards acoustics
Vibrating diaphragm centrally along stretching, but the edge of stop tab stretch distance can not be oversize, i.e., stop tab distance is unsuitable oversize, if stop tab
Afterbody and cylinder (fulcrum) between distance it is longer, the afterbody of stop tab occurs sagging because of action of gravity, it is sagging after
Although stop tab still have limit effect, while the deformational displacement for limiting acoustic diaphragm (reduces acoustic diaphragm
Deformational displacement distance), reduce the accuracy of MEMS microphone sound collection, in addition in the fabrication process, along long position-limited wing
Processing technology required for piece is relatively complicated, and yield rate is not high.
In order to overcome above-mentioned technical scheme, a kind of structural representation of MEMS microphone as shown in Figure 3, including:
One MEMS chip, the MEMS chip 1 include a substrate 11, and one are arranged at the acoustics on the substrate 11 and shake
Film 12;Further, also include electrode slice 14 on MEMS chip 1, electrode slice 14 is to realize the transmission of the signal of telecommunication.
Position limiting structure 2, is arranged along 12 outer fringe surface of the acoustic diaphragm, so that the position limiting structure 2 combines the substrate
Form a spacing cavity for limiting 12 deformational displacement of acoustic diaphragm.Position limiting structure 2 includes cylinder 22, stop tab 23 and bottom
Plate 21, wherein, a through hole 121 for matching the cylinder 22 is set on the acoustic diaphragm 12, the cylinder 22 is through described
So that the base plate 21 is fixedly installed on the substrate, the stop tab 23 of the limiting plate of falling embedded described in a pair hangs through hole 121
Sky is fixed on above the acoustic diaphragm 12.
One through hole 121 is set in acoustic diaphragm 12, and the cylinder 22 runs through the through hole 121 so that the base plate 21 is solid
Surely it is arranged on the substrate, i.e., the base plate 21 is arranged at below the acoustic diaphragm 12, and the stop tab 23 is arranged at
Above the acoustic diaphragm 12, without the need for being capable of achieving position-limiting action along the length for stretching the stop tab 23.One conveniently ensure that
The deformational displacement of acoustic diaphragm 12, on the other hand also reduces the making complexity of position limiting structure.In addition, on acoustic diaphragm 12
One through hole 121 is set, radiation damping of the acoustic diaphragm 12 in vibration processes is greatly reduced.
During acoustic pressure causes 12 vibration processes of acoustic diaphragm, acoustic pressure forms a particle on acoustic diaphragm 12, and acoustic pressure is with the matter
The radiation damping that energy is gradually reduced is formed further to surrounding radiative acoustic wave centered on point, when radiation damping generally needs one
Between, when next acoustic pressure promotes acoustic diaphragm 12 to deform upon displacement, (sound is continuous signal, and then acoustic pressure is also a company
Continuous signal), the radiation damping that a upper acoustic pressure causes still in radiation, is caused under the radiation damping suppression that an acoustic pressure causes
The deformational displacement of the acoustic diaphragm 12 that one acoustic pressure causes, and then MEMS microphone signal to noise ratio is reduced, in this utility model,
A through hole 121 is formed in acoustic diaphragm 12, when radiation damping is radiated to the through hole 121, the through hole 121 absorbs radiation damping,
And then avoid the radiation damping that an acoustic pressure causes from affecting 12 deformational displacement of acoustic diaphragm that next acoustic pressure causes.It is intended to carry
The signal to noise ratio of high MEMS microphone.
Need explanation when, the position for being located away from MEMS acoustics through holes of the setting of the through hole 121, if through hole 121
Setting it is corresponding with the position of matching MEMS acoustics through holes, then the position that the through hole 121 is located easily becomes acoustic pressure and exists
The particle formed on acoustic diaphragm 12, when 121 position of through hole is identical with radiation damping particle position, through hole 121 absorbs all
Radiation damping, then acoustic diaphragm 12 cannot then produce deformational displacement, and then cannot gather any acoustical signal.
In above-mentioned technical proposal, above-mentioned MEMS microphone, wherein, the bottom of the acoustic diaphragm 12 is towards the substrate
The side in direction is provided with projection.Further, also including back pole plate 15, the back pole plate 15 is fixedly installed on the substrate
Precalculated position, so that the back pole plate 15 forms a capacity plate antenna structure with the acoustic diaphragm 12.Acoustic diaphragm 12 for thin and
Resilient diaphragm, in the lower generation deformational displacement of physical resonant motion effect, i.e., acoustic diaphragm 12 is in gradient pressure for acoustic diaphragm 12
Do of reciprocating vibration up and down deviateing equilbrium position under power effect, because the lower section of acoustic diaphragm 12 is provided with back pole plate 15, in order to
Prevent acoustic diaphragm 12 from pasting with back pole plate 15 when vibrating downwards, in the bottom of the acoustic diaphragm 12 towards the lining
The side in bottom direction is provided with projection, and further, the projection is anti-grume.It is intended to the accurate of MEMS microphone sound collection
Degree, it is to avoid acoustic diaphragm 12 is pasted the back pole plate 15 and cannot continue to deform upon displacement.Further, anti-grume can be to lead
Electric material, alternatively electrically non-conductive material.Herein the material of anti-grume is not particularly limited.
In above-mentioned technical proposal, above-mentioned MEMS microphone, wherein, the MEMS chip also includes elastic construction, described
Elastic construction is fixedly installed between the acoustic diaphragm 12 and the substrate.
Gap generally between acoustic diaphragm 12 and back pole plate 15 determines the scope of MEMS microphone sound collection, in order to
Expand the scope of MEMS microphone sound collection, come real often through the gap expanded between acoustic diaphragm 12 and back pole plate 15
It is existing.But this kind of mode is unfavorable for the Integration Design of MEMS microphone, for this purpose, in this utility model, also including elastic construction,
The elastic construction is fixedly installed between the acoustic diaphragm 12 and the substrate, arranges a bullet in the bottom of acoustic diaphragm 12
Property structure, in the case where original spacing distance is constant, by elastic construction increase acoustic diaphragm 12 behavior displacement, favorably
In the Integration Design of MEMS microphone.
Further, elastic construction can be formed by spring front line 13, spring, spring, spring front line 13 and acoustic diaphragm 12
Junction is made of an electrically conducting material, and conductive material can be silicon, and spring, spring front line 13 are with substrate junction by insulant system
Into, insulant can be silicon dioxide, it should be noted that the composition of elastic construction is only a kind of way of example herein, not
It is to concrete restriction of the present utility model.
Note, above are only preferred embodiment of the present utility model and institute's application technology principle.Those skilled in the art's meeting
Understand, this utility model is not limited to specific embodiment described here, can carry out for a person skilled in the art various bright
Aobvious change, readjust and substitute without departing from protection domain of the present utility model.Therefore, although by above example
This utility model is described in further detail, but this utility model is not limited only to above example, without departing from
In the case that this utility model is conceived, more other Equivalent embodiments can also be included, and scope of the present utility model is by appended
Right determine.