CN117376758A - Microphone assembly and electronic equipment - Google Patents
Microphone assembly and electronic equipment Download PDFInfo
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- CN117376758A CN117376758A CN202311665898.XA CN202311665898A CN117376758A CN 117376758 A CN117376758 A CN 117376758A CN 202311665898 A CN202311665898 A CN 202311665898A CN 117376758 A CN117376758 A CN 117376758A
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- 239000000758 substrate Substances 0.000 claims abstract description 87
- 239000004020 conductor Substances 0.000 claims description 104
- 239000012212 insulator Substances 0.000 claims description 23
- 230000000149 penetrating effect Effects 0.000 claims description 8
- 239000011810 insulating material Substances 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 description 15
- 238000013016 damping Methods 0.000 description 10
- 238000000429 assembly Methods 0.000 description 3
- 230000000712 assembly Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002019 doping agent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 229920005591 polysilicon Polymers 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 244000126211 Hericium coralloides Species 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 230000005226 mechanical processes and functions Effects 0.000 description 1
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- 239000004065 semiconductor Substances 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
Classifications
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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
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/08—Mouthpieces; Microphones; Attachments therefor
- H04R1/083—Special constructions of mouthpieces
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
Abstract
The embodiment of the invention discloses a microphone assembly and an electronic device, wherein the microphone assembly comprises: a substrate, a first electrode, a second electrode, a third electrode, and a movable dielectric layer; the longitudinal direction of each of the first electrode, the second electrode, and the third electrode is parallel to the thickness direction of the substrate; the movable dielectric layer is provided with a vibration sensitive area, a plurality of through holes are formed in the circumferential direction of the vibration sensitive area at intervals, the through holes penetrate through the movable dielectric layer in the thickness direction, and the first electrode, the second electrode and the third electrode are respectively at least partially penetrated in the corresponding through holes; wherein the first electrode and the second electrode are partially opposed to constitute a first capacitance, the second electrode and the third electrode are partially opposed to constitute a second capacitance, and the first capacitance and the second capacitance constitute a differential capacitance. According to the invention, the signal to noise ratio of the microphone product is remarkably improved.
Description
Technical Field
The present disclosure relates to microphone assemblies, and particularly to a microphone assembly and an electronic device.
Background
The microphone is a pressure sensor that finally converts a sound pressure signal into an electrical signal, and a small microphone manufactured using a Micro Electro mechanical process technology is called a MEMS (Micro-Electro-Mechanical System) microphone or a Micro microphone. MEMS microphone chips generally include a substrate, a diaphragm, and a backplate. The vibrating diaphragm and the back polar plate are important parts in the MEMS microphone chip, the vibrating diaphragm and the back polar plate are parallel and are arranged at intervals, the vibrating diaphragm and the back polar plate form two electrode plates of the panel capacitor, the vibrating diaphragm is used for vibrating under the action of sound waves, so that the relative distance between the back polar plate and the vibrating diaphragm is changed, the capacitance value of the panel capacitor is changed, and the change of the capacitance value is converted into an electric signal through a peripheral circuit, so that the conversion of sound and electricity is realized.
With the expansion of MEMS microphone application scenarios (e.g., applications that sing by mobile phone, etc.), the requirements of users on the voice quality of MEMS microphones are increasing. In order to improve the signal-to-noise ratio of the electrical signal induced by the MEMS microphone, in the prior art, the MEMS microphone generally uses a multi-diaphragm mode or a multi-back-plate mode to obtain the differential electrical signal. In addition, in the scheme of adopting the mode of many back plates to acquire the difference signal of telecommunication, in order to reduce the press film damping between back plate and the vibrating diaphragm, prior art often has seted up the mode of sound hole or setting up great fretwork area through the back plate and has promoted signal to noise ratio, and this makes the pollutant in the external environment also very easily enter into the gap in between back plate and the vibrating diaphragm through sound hole or great fretwork area department on the back plate for the reliability of product descends.
Disclosure of Invention
The embodiment of the invention provides a microphone assembly and electronic equipment, which are used for improving the signal to noise ratio of a microphone product and improving the reliability of the microphone product.
In order to solve the technical problems, the embodiment of the invention discloses the following technical scheme:
in one aspect, a microphone assembly is provided, comprising: a substrate, a first electrode, a second electrode, a third electrode, and a movable dielectric layer;
the substrate has a back cavity penetrating in a thickness direction thereof, and a longitudinal direction of each of the first electrode, the second electrode, and the third electrode is parallel to the thickness direction of the substrate;
the movable dielectric layer is provided with a vibration sensitive area, a plurality of through holes are formed in the circumferential direction of the vibration sensitive area at intervals, the through holes penetrate through the movable dielectric layer in the thickness direction, and the first electrode, the second electrode and the third electrode are respectively at least partially penetrated in the corresponding through holes;
wherein the first electrode and the second electrode portion are opposed to constitute a first capacitance, and the second electrode and the third electrode portion are opposed to constitute a second capacitance, wherein the first capacitance and the second capacitance constitute a differential capacitance.
Further, in the thickness direction of the substrate, the movable dielectric layer has a first surface and a second surface which are oppositely arranged, wherein the first surface is positioned on one side of the second surface close to the substrate; the first electrode has a first end proximal to the substrate and a second end distal to the substrate, the second electrode has a third end proximal to the substrate and a fourth end distal to the substrate, the third electrode has a fifth end proximal to the substrate and a sixth end distal to the substrate; wherein the second end is located between the first surface and the second surface and the fifth end is located between the first surface and the second surface.
Further, the third end is located on a side of the first surface remote from the second surface, and the fourth end is located on a side of the second surface remote from the first surface;
alternatively, the third end is flush with the first surface, and the fourth end is located on a side of the second surface remote from the first surface;
alternatively, the third end is located on a side of the first surface remote from the second surface, and the fourth end is flush with the second surface;
alternatively, the third end is flush with the first surface and the fourth end is flush with the second surface.
Further, the cross section of the through hole is in a strip shape, and the length extension direction of the cross section of the through hole faces the geometric center of the vibration sensitive area;
the first electrode, the second electrode and the third electrode are respectively matched with the corresponding through holes.
Further, the first electrode, the second electrode, and the third electrode are any one of a tooth-like structure, a plate-like structure, or a columnar structure.
Further, the plurality of through holes include a plurality of through hole unit groups, each including a first through hole, a second through hole, and a third through hole sequentially arranged in a circumferential direction of the vibration sensitive area;
the first electrode at least partially penetrates through the first through hole, the second electrode at least partially penetrates through the second through hole, and the third electrode at least partially penetrates through the third through hole.
Further, the microphone assembly further includes a first conductor, a second conductor, and a third conductor stacked on the substrate side, the first conductor being connected to the first electrode, the second conductor being connected to the second electrode, and the third conductor being connected to the third electrode;
wherein, in a thickness direction of the substrate, the first conductor is positioned between the substrate and the movable dielectric layer, the second conductor is positioned between the movable dielectric layer and the third conductor, and the third conductor is positioned on a side of the second conductor away from the substrate;
the first conductor, the second conductor, and the third conductor are all located at an edge of the substrate.
Further, the first conductor has at least one first hollowed-out area, the second conductor has at least one second hollowed-out area, and the third conductor has at least one third hollowed-out area;
in the thickness direction of the substrate, the projections of the at least one first hollow area, the at least one second hollow area, the at least one third hollow area and the back cavity overlap.
Further, in the thickness direction of the substrate, a first insulator for supporting the first conductor is provided on a side of the substrate close to the movable dielectric layer, and a second insulator for supporting the third conductor is provided between the second conductor and the third conductor;
the first insulator and the second insulator are positioned at the edge of the substrate.
Further, the movable dielectric layer is a flexible and insulating material.
Further, the dielectric constant of the movable dielectric layer is greater than or equal to 2.
Optionally, the movable dielectric layer further includes: a support portion disposed around the vibration sensitive region, the support portion being located at an edge of the substrate; and the at least one elastic beam fixedly connects the vibration sensitive area with the supporting part.
Optionally, the movable dielectric layer has at least one fourth hollowed-out area surrounding the vibration sensitive area; the vibration sensitive region of the movable dielectric layer is in contact with the support structure disposed in the back cavity and secured to the substrate.
According to another aspect of the present invention, there is also provided an electronic device including any one of the microphone assemblies described above.
Compared with the prior art, the technical scheme provided by the embodiment of the invention can convert the film pressing damping between the vibrating diaphragm and the back electrode plate in the prior art into the sliding film damping of each electrode in the through hole of the movable medium layer, so that the damping of the microphone assembly in working is reduced by about one order of magnitude, and the signal to noise ratio of a microphone product is obviously improved. And can also eliminate the problem of reduced reliability of microphone products caused by contaminants possibly existing in the prior art entering the gap layer between the back plate and the diaphragm.
Drawings
The technical solution and other advantageous effects of the present invention will be made apparent by the following detailed description of the specific embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a microphone assembly according to an embodiment of the invention.
Fig. 2 is a schematic side view of a microphone assembly according to an embodiment of the invention.
Fig. 3 is a schematic top view of a microphone assembly according to an embodiment of the invention.
Fig. 4 is a schematic diagram of an arrangement according to fig. 1 after the three electrodes constituting the differential capacitance and the movable dielectric layer located between the adjacent two electrodes are developed in the circumferential direction of the vibration-sensitive area.
Fig. 5 is a schematic view of a partial structure of a substrate provided with a first insulator, a first conductor and a movable dielectric layer according to an embodiment of the present invention.
Fig. 6 is a schematic top view of the movable dielectric layer according to fig. 5 provided with a through hole.
Fig. 7 is a schematic top view of the first electrical conductor according to fig. 1.
Fig. 8 is a schematic top view of the second electrical conductor according to fig. 1.
Fig. 9 is a schematic top view of the third electrical conductor according to fig. 1.
Fig. 10 is a schematic side view of a microphone assembly according to another embodiment of the invention.
Fig. 11 is a schematic top view of the movable dielectric layer according to fig. 10.
Fig. 12 is a schematic side view of a microphone assembly according to another embodiment of the invention.
Fig. 13 is a schematic top view of the movable dielectric layer according to fig. 12.
Fig. 14 is a schematic view of a structure of the substrate according to fig. 12.
The main reference numerals:
10. a substrate; 11. a back cavity; 31. a first electrode; 51. a second electrode; 71. a third electrode; 40. a movable dielectric layer; 40A, a first surface of the movable dielectric layer; 40B, a second surface of the movable dielectric layer; 41. a vibration sensitive area; 43. a through hole; 31A, a first end; 31B, a second end; 51A, a third end; 51B, fourth end; 71A, fifth end; 71B, sixth end; 431. a first through hole; 432. a second through hole; 433. a third through hole; 430. a through-hole unit group; 30. a first conductor; 50. a second conductor; 70. a third conductor; 420. a support section; 421. an elastic beam; 44. a fourth hollowed-out area; 180. and a support structure.
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and detailed description. It should be understood that the detailed description is intended to illustrate the invention, and not to limit the invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The embodiment of the invention provides a microphone assembly, which is a core component of an MEMS microphone, and can be applied to electronic equipment with a sound collection function, such as a smart phone, a tablet personal computer, a recording pen, a hearing aid, vehicle-mounted equipment and the like. The embodiment of the invention is not limited to the application scenario.
At least one embodiment of the present invention provides a microphone assembly including a substrate, a first electrode, a second electrode, a third electrode, and a movable dielectric layer;
the substrate has a back cavity penetrating in a thickness direction thereof, and a longitudinal direction of each of the first electrode, the second electrode, and the third electrode is parallel to the thickness direction of the substrate;
the movable dielectric layer is provided with a vibration sensitive area, a plurality of through holes are formed in the circumferential direction of the vibration sensitive area at intervals, the through holes penetrate through the movable dielectric layer in the thickness direction, and the first electrode, the second electrode and the third electrode are respectively at least partially penetrated in the corresponding through holes;
wherein the first electrode and the second electrode portion are opposed to constitute a first capacitance, and the second electrode and the third electrode portion are opposed to constitute a second capacitance, wherein the first capacitance and the second capacitance constitute a differential capacitance.
As can be seen from the foregoing, in the embodiment of the present invention, by designing the first electrode, the second electrode, the third electrode, and one movable dielectric layer, the longitudinal direction of each of the first electrode, the second electrode, and the third electrode is parallel to the thickness direction of the substrate, a plurality of through holes are formed in the circumferential direction of the vibration sensitive area of the movable dielectric layer at intervals, the through holes penetrate through the movable dielectric layer in the thickness direction, and each of the first electrode, the second electrode, and the third electrode at least partially penetrates through the corresponding through hole, wherein the first electrode and the second electrode are partially opposite to each other to form a first capacitor, and the second electrode and the third electrode are partially opposite to each other to form a second capacitor, and the first capacitor and the second capacitor form a differential capacitor.
In the embodiment of the invention, the movable dielectric layer is suspended above the back cavity, and the sound pressure load during normal operation and the blowing load during abnormal operation can be loaded on the movable dielectric layer through the back cavity, and then the movable dielectric layer vibrates and moves towards one side away from the back cavity, so that the ratio of the movable dielectric layer to air in the opposite area between the first electrode and the second electrode is changed, namely the equivalent dielectric constant in the opposite area between the first electrode and the second electrode is changed, and the size of the first capacitor is further changed; and the ratio of the movable dielectric layer to the air in the opposite region between the second electrode and the third electrode is changed, namely the equivalent dielectric constant in the opposite region between the second electrode and the third electrode is changed, so that the magnitude of the second capacitance is changed, the first capacitance and the second capacitance form a differential capacitance, compared with the prior art, the technical scheme of the invention can convert the film pressing damping between the vibrating diaphragm and the back electrode plate in the prior art into the sliding film damping of each electrode in the through hole of the movable medium layer, so that the damping of the microphone assembly during working is reduced by about one order of magnitude, and the signal to noise ratio of a microphone product is obviously improved. And can also eliminate the problem of reduced reliability of microphone products caused by contaminants possibly existing in the prior art entering the gap layer between the back plate and the diaphragm.
Fig. 1 is a schematic structural view of a microphone assembly according to an embodiment of the present invention, fig. 2 is a schematic structural view of a side view of a microphone assembly according to an embodiment of the present invention, fig. 3 is a schematic structural view of a top view of a microphone assembly according to an embodiment of the present invention, and fig. 4 is a schematic layout of three electrodes constituting a differential capacitor and a movable dielectric layer between two adjacent electrodes according to fig. 1 after being spread along a circumferential direction of a vibration sensitive area.
Referring to fig. 1 to 4, the microphone assembly includes a substrate 10, a first electrode 31, a second electrode 51, a third electrode 71, and a movable dielectric layer 40; the substrate 10 has a back cavity 11 penetrating in a thickness direction thereof, and a longitudinal direction of each of the first electrode 31, the second electrode 51, and the third electrode 71 is parallel to the thickness direction of the substrate 10; the movable dielectric layer 40 has a vibration sensitive area 41, a plurality of through holes 43 are formed in the circumferential direction of the vibration sensitive area 41 at intervals, the through holes 43 penetrate through the movable dielectric layer 40 in the thickness direction, and the first electrode 31, the second electrode 51 and the third electrode 71 are respectively at least partially penetrated into the corresponding through holes 43; wherein the first electrode 31 and the second electrode 51 are partially opposed to constitute a first capacitance, and the second electrode 51 and the third electrode 71 are partially opposed to constitute a second capacitance, wherein the first capacitance and the second capacitance constitute a differential capacitance.
Illustratively, in this embodiment, the first electrode 31, the second electrode 51, and the third electrode 71 each include a conductive medium, such as polysilicon, or doped in a semiconductor material to form an N-type dopant or a P-type dopant.
Illustratively, in some embodiments, the movable dielectric layer 40 is a flexible and insulating material, such that the movable dielectric layer 40 is capable of producing a large amount of deformation while also having insulating properties, such as a silicon oxide or silicon nitride material.
It should be understood that, in the embodiment, the dielectric constant of the movable dielectric layer 40 is greater than or equal to 2, and the dielectric constant of air is generally 1, so that there is a large difference between the dielectric constants of the movable dielectric layer and air, when the acoustic wave load acts on the movable dielectric layer and causes the movable dielectric layer to move, the equivalent dielectric constant of the first capacitor is reduced due to, for example, the reduction of the ratio between the movable dielectric layer and air, so that the first capacitor is reduced, and the equivalent dielectric constant of the second capacitor is reduced due to the increase of the ratio between the movable dielectric layer and air, so that the second capacitor is increased, and the acoustic wave change of the microphone can be detected very sensitively according to the change of the differential capacitance formed by the first capacitor and the second capacitor.
Further, in the thickness direction of the substrate 10, the movable dielectric layer 40 has a first surface 40A and a second surface 40B that are disposed opposite to each other, wherein the first surface 40A is located on a side of the second surface 40B that is close to the substrate 10;
the first electrode 31 has a first end 31A close to the substrate 10 and a second end 31B remote from the substrate, the second electrode 51 has a third end 51A close to the substrate 10 and a fourth end 51B remote from the substrate 10, and the third electrode 71 has a fifth end 71A close to the substrate 10 and a sixth end 71B remote from the substrate 10; wherein the second end 31B is located between the first surface 40A and the second surface 40B, and the fifth end 71A is located between the first surface 40A and the second surface 40B.
It should be noted that, in the embodiment of the present invention, the second electrode 51 may be completely disposed in a corresponding through hole, for example, two ends of the second electrode 51 extend out of the first surface and the second surface of the movable dielectric layer 40.
Illustratively, in some embodiments, the third end 51A is located on a side of the first surface 40A remote from the second surface 40B, and the fourth end 51B is located on a side of the second surface (40B) remote from the first surface 40A.
Alternatively, in some embodiments, the third end 51A is flush with the first surface 40A and the fourth end 51B is located on a side of the second surface 40B remote from the first surface 40A.
Alternatively, in some embodiments, the third end 51A is located on a side of the first surface 40A remote from the second surface 40B, and the fourth end 51B is flush with the second surface 40B.
Alternatively, in some embodiments, the third end 51A is flush with the first surface 40A and the fourth end 51B is flush with the second surface 40B.
That is, the second electrode 51 may have one end protruding from the first surface 40A or the second surface 40B of the movable dielectric layer 40 and the other end may be flush with one side surface of the movable dielectric layer 40.
Further, fig. 5 is a schematic partial structure of a substrate provided with a first insulator, a first conductor and a movable dielectric layer according to an embodiment of the present invention. Fig. 6 is a schematic top view of the movable dielectric layer according to fig. 5 provided with a through hole.
Referring to fig. 5 and 6, the cross-sectional shape of the through hole 43 is a bar shape, and the length extension direction of the cross-section of the through hole 43 is toward the geometric center of the vibration sensitive area 41; the first electrode 31, the second electrode 51, and the third electrode 71 are respectively adapted to the corresponding through holes 43.
In this embodiment, the length extending direction of the cross section of the through hole 43 faces the geometric center of the vibration sensitive area 41, that is, a plurality of through holes 43 are radially arranged around the geometric center of the vibration sensitive area 41, so as to arrange a greater number of through holes in the circumferential direction of the vibration sensitive area 41.
It should be appreciated that the above arrangement of the plurality of through holes may enable as many of the movable dielectric layers 40 to be sandwiched between the first electrode 31 and the second electrode 51, and as many of the movable dielectric layers 40 to be sandwiched between the second electrode 51 and the third electrode 71, so as to improve the sensitivity of the microphone assembly.
Further, in the embodiment of the present invention, the first electrode 31, the second electrode 51, and the third electrode 71 are any one of a tooth-like structure, a plate-like structure, or a columnar structure. The tooth-shaped structure can be a comb tooth structure, the plate-shaped structure can be a parallel plate structure or a curved plate structure, and the columnar structure can be a square column or a cylinder and the like.
Further, the plurality of through holes 43 includes a plurality of through hole unit groups 430, each through hole unit group 430 includes a first through hole 431, a second through hole 432, and a third through hole 433 sequentially arranged in the circumferential direction of the vibration sensitive area 41, the first electrode 31 is at least partially inserted into the first through hole 431, the second electrode 51 is at least partially inserted into the second through hole 432, and the third electrode 71 is at least partially inserted into the third through hole 433.
Illustratively, in the circumferential direction of the vibration sensitive area 41, the first through-holes 431, the second through-holes 432, and the third through-holes 433 in each through-hole unit group 430 may be arranged in a continuous manner. The third through holes 433, the second through holes 432, and the first through holes 431 in each through hole unit group 430 may be arranged in a continuous manner. Of course, the partial through hole unit group 430 may be formed by connecting the first through hole 431, the second through hole 432, and the third through hole 433, and the partial through hole unit group 430 may be formed by connecting the third through hole 433, the second through hole 432, and the first through hole 431, or two adjacent through hole unit groups 430 may share one first through hole 431 or one third through hole 433.
In some embodiments, the number of the plurality of through holes 43 may be 3*N, wherein N is a positive integer; when the number of N is greater, the number of the first electrodes 31, the second electrodes 51 and the third electrodes 71 can be simultaneously accommodated is greater, so that the equivalent facing areas formed between the plurality of first electrodes 31 and the plurality of second electrodes 51 are greater, and the equivalent facing areas formed between the plurality of second electrodes 51 and the plurality of third electrodes 71 are greater, so that the differential capacitance values formed between all the first capacitances and all the second capacitances detected by the microphone assembly are greater.
Illustratively, in this embodiment, the first electrode 31, the second electrode 51, and the third electrode 71 may each be provided as a fixed electrode, i.e., a fixed relative position with respect to the substrate 10.
As illustrated with continued reference to fig. 1 and 2, the microphone assembly further includes a first conductor 30, a second conductor 50, and a third conductor 70 stacked on one side of the substrate 10, the first conductor 30 being connected to the first electrode 31 to apply or transmit an electrical signal to the first electrode 31, the second conductor 50 being connected to the second electrode 51 to apply or transmit an electrical signal to the second electrode 51, the third conductor 70 being connected to the third electrode 71 to apply or transmit an electrical signal to the third electrode 71; wherein the first conductor 30 is located between the substrate 10 and the movable dielectric layer 40 in the thickness direction of the substrate 10, the second conductor 50 is located between the movable dielectric layer 40 and the third conductor 70, and the third conductor 70 is located on a side of the second conductor 50 away from the substrate 10; the first conductor 30, the second conductor 50, and the third conductor 70 are all located at the edge of the substrate 10.
Illustratively, the first, second and third conductors 30, 50 and 70 may be sequentially stacked over the substrate 10 by deposition, for example, depositing a silicon material layer and P-type doping or N-type doping it to form a conductive layer, or directly depositing a polysilicon material layer to have conductivity such that an electrical signal between the first electrode 31 and an external circuit is transmitted through the first conductor 30, an electrical signal between the second electrode 51 and an external circuit is transmitted through the second conductor 50, and an electrical signal between the third electrode 71 and an external circuit is transmitted through the third conductor 70.
Fig. 7 is a schematic top view of the first conductor according to fig. 1, fig. 8 is a schematic top view of the second conductor according to fig. 1, and fig. 9 is a schematic top view of the third conductor according to fig. 1.
As illustrated in fig. 7-9, and as shown in fig. 1-2, the first conductor 30 has at least one first hollowed-out area 301, the second conductor 50 has at least one second hollowed-out area 501, and the third conductor 70 has at least one third hollowed-out area 701; in the thickness direction of the substrate 10, the projections of the at least one first hollowed-out area 301, the at least one second hollowed-out area 501, the at least one third hollowed-out area 701, and the back cavity 11 overlap, so that the circulation of the sound wave air flow is facilitated, the sensitivity and reliability of the microphone product are improved, and the respective stresses on the first conductor 30, the second conductor 50, and the third conductor 70 can be released.
Illustratively, a first hollow area 301 is disposed in the middle of the first conductor 30, a second hollow area 501 is disposed in the middle of the second conductor 50, and a third hollow area 701 is disposed in the middle of the third conductor 70, so as to jointly form an oscillating acoustic cavity for the movable dielectric layer 40 to vibrate; at this time, the first electrode 31 may be suspended above the back cavity 11, the second electrode 51 may be suspended above the back cavity 11, and the third electrode 71 may be suspended above the back cavity 11.
It should be understood that the first conductive body 30 may further be provided with a plurality of first hollow areas 301, the second conductive body 50 may further be provided with a plurality of second hollow areas 501, and the third conductive body 70 may further be provided with a plurality of third hollow areas 701, which is not limited herein.
Further, the microphone assembly further includes: a first insulator 20 for supporting the first conductor 30 is provided on a side of the substrate 10 close to the movable dielectric layer 40 in the thickness direction of the substrate 10, and a second insulator 60 for supporting the third conductor 70 is provided between the second conductor 50 and the third conductor 70; the first insulator 20 and the second insulator 60 are located at the edge of the substrate 10.
In this embodiment, the first insulator 20 and the second insulator 60 may be made of silicon oxide, silicon nitride, or the like. The thickness of the first insulator 20 and the second insulator 60 is between 2 um and 3um, for example, the thickness of the first insulator 20 and the second insulator 60 is around 2.5 um. The first insulator 20 is supported between the substrate 10 and the first conductor 30, and is used for electrically isolating the first conductor 30 from the substrate 10, so that a gap is formed between the first conductor 30 and the substrate 10, and the first conductor 30 is electrically isolated, and provides support for the first conductor 30. The movable dielectric layer 40 is supported between the first conductor 30 and the second conductor 50, and is used for electrically isolating the first conductor 30 and the second conductor 50, so that a gap exists between the first conductor 30 and the second conductor 50 and is electrically isolated, and the support is provided for the second conductor 50. The second insulator 60 is supported between the second conductor 50 and the third conductor 70, and is used for electrically isolating the second conductor 50 from the third conductor 70, so that a gap exists between the second conductor 50 and the third conductor 70 and is electrically isolated, and the third conductor 70 is supported.
It should be appreciated that in embodiments of the present invention, the movable dielectric layer 40 further includes a support portion disposed around the vibration sensitive area 41; the support portion is located between the first insulator 20 and the second conductor 50 in the thickness direction of the substrate 10 such that the periphery of the movable dielectric layer 40 is supported.
Fig. 10 is a schematic side view of a microphone assembly according to another embodiment of the invention, and fig. 11 is a schematic top view of the movable dielectric layer according to fig. 10.
Illustratively, as shown in fig. 10-11, in some other embodiments, the movable dielectric layer 40 further includes: a support part 420, the support part 420 being disposed around the vibration sensitive area 41, and the support part 420 being located at an edge of the substrate 10; at least one elastic beam 421, the at least one elastic beam 421 fixedly connects the vibration sensitive area 41 and the supporting portion 420, and by providing at least one elastic beam 421 around the vibration sensitive area and connecting the supporting portion 420, the moving width of the movable dielectric layer 40 right above the back cavity 11 can be increased, and the life and reliability of the movable dielectric layer 40 itself can be improved. Illustratively, the support portion 420 may have one or more hollowed-out regions between the vibration sensitive regions 41.
Fig. 12 is a schematic side view of a microphone assembly according to another embodiment of the invention, fig. 13 is a schematic top view of the movable dielectric layer according to fig. 12, and fig. 14 is a schematic structure of the substrate according to fig. 12.
12-14, in some other embodiments, the movable dielectric layer 40 has at least one fourth hollowed-out region 44, the at least one fourth hollowed-out region 44 surrounding the vibration sensitive region 41; the vibration sensitive area 41 of the movable dielectric layer 40 is in contact with the support structure 180 provided in the back cavity 11 and fixed to the substrate 10.
Specifically, the support structure 180 includes a main body portion 181 and a support portion 182, where the main body portion 181 is located in the back cavity 11 and is fixedly connected to a side wall of the back cavity 11 through the support portion 182; wherein, a protruding portion 183 is disposed on a surface of the main body portion 181 near the movable dielectric layer 40, the protruding portion 183 contacts the movable dielectric layer 40 to support the movable dielectric layer 40, and a region of the movable dielectric layer 40 except a contact portion with the protruding portion 183 is suspended above the back cavity 11. In an embodiment of the present invention, the number of the protruding portions 183 may be 1 or more. Preferably, the number of the protruding portions 183 is 1, that is, a single-point supporting structure is adopted to reduce the contact area between the first supporting structure 180 and the movable dielectric layer 40, so that the area of the effective vibration area of the movable dielectric layer 40 except for the contact portion with the protruding portions 183 is increased, thereby further improving the sensitivity of vibration of the movable dielectric layer 40, and further achieving the purpose of improving the signal-to-noise ratio of the microphone product.
Further, in order to improve the support balance of the support structure 180 supporting the movable dielectric layer 40, the support structure 180 may correspond to a center position of the movable dielectric layer 40, and at this time, the main body portion 181 of the support structure 180 is just located in the middle of the back cavity 11, so as to more smoothly carry the movable dielectric layer 40.
Optionally, the supporting portion 182 includes at least one cross member 1821, and the main body portion 181 is fixedly connected to the side wall 1 of the back cavity 11 through the at least one cross member 1821. Preferably, in the embodiment of the present invention, the cross section of the main body portion 181 is circular, and the longitudinal section of the main body portion 181 is trapezoidal to block instantaneous impact air flow from the external space from being vertically loaded onto the surface of the movable dielectric layer 40.
According to another aspect of the present invention there is also provided an electronic device comprising any of the microphone assemblies described above. The microphone assembly can be applied to various electronic devices, such as a smart phone, a tablet computer, a recording pen, a hearing aid, a vehicle-mounted device and the like.
Therefore, the microphone assembly and the electronic equipment provided by the embodiment of the invention remarkably improve the signal-to-noise ratio of the microphone. Wherein the microphone assembly comprises a substrate, a first electrode, a second electrode, a third electrode, and a movable dielectric layer; the substrate has a back cavity penetrating in a thickness direction thereof, and a longitudinal direction of each of the first electrode, the second electrode, and the third electrode is parallel to the thickness direction of the substrate; the movable dielectric layer is provided with a vibration sensitive area, a plurality of through holes are formed in the circumferential direction of the vibration sensitive area at intervals, the through holes penetrate through the movable dielectric layer in the thickness direction, and the first electrode, the second electrode and the third electrode are respectively at least partially penetrated in the corresponding through holes; wherein the first electrode and the second electrode portion are opposed to constitute a first capacitance, and the second electrode and the third electrode portion are opposed to constitute a second capacitance, wherein the first capacitance and the second capacitance constitute a differential capacitance. Compared with the prior art, the technical scheme of the invention can convert the film pressing damping between the vibrating diaphragm and the back polar plate in the prior art into the sliding film damping of each electrode in the through hole of the movable medium layer, so that the damping of the microphone assembly in working is reduced by about one order of magnitude, and the signal to noise ratio of a microphone product is obviously improved.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (14)
1. A microphone assembly characterized by comprising a substrate (10), a first electrode (31), a second electrode (51), a third electrode (71), and a movable dielectric layer (40);
the substrate (10) has a back cavity (11) penetrating in a thickness direction thereof, and a longitudinal direction of each of the first electrode (31), the second electrode (51), and the third electrode (71) is parallel to the thickness direction of the substrate (10);
the movable dielectric layer (40) is provided with a vibration sensitive area (41), a plurality of through holes (43) are formed in the circumferential direction of the vibration sensitive area (41) at intervals, the through holes (43) penetrate through the movable dielectric layer (40) in the thickness direction, and each of the first electrode (31), the second electrode (51) and the third electrode (71) at least partially penetrates through the corresponding through hole (43);
wherein the first electrode (31) and the second electrode (51) are partially opposed to constitute a first capacitance, and the second electrode (51) and the third electrode (71) are partially opposed to constitute a second capacitance, wherein the first capacitance and the second capacitance constitute a differential capacitance.
2. A microphone assembly as recited in claim 1, wherein,
the movable dielectric layer (40) has a first surface (40A) and a second surface (40B) which are oppositely arranged in the thickness direction of the substrate (10), wherein the first surface (40A) is positioned on one side of the second surface (40B) close to the substrate (10);
the first electrode (31) has a first end (31A) close to the substrate (10) and a second end (31B) distant from the substrate (10), the second electrode (51) has a third end (51A) close to the substrate (10) and a fourth end (51B) distant from the substrate (10), the third electrode (71) has a fifth end (71A) close to the substrate (10) and a sixth end (71B) distant from the substrate (10); wherein the second end (31B) is located between the first surface (40A) and the second surface (40B), and the fifth end (71A) is located between the first surface (40A) and the second surface (40B).
3. A microphone assembly as recited in claim 2, wherein,
-the third end (51A) is located on a side of the first surface (40A) remote from the second surface (40B), and-the fourth end (51B) is located on a side of the second surface (40B) remote from the first surface (40A);
alternatively, the third end (51A) is flush with the first surface (40A), and the fourth end (51B) is located on a side of the second surface (40B) remote from the first surface (40A);
alternatively, the third end (51A) is located on a side of the first surface (40A) remote from the second surface (40B), the fourth end (51B) being flush with the second surface (40B);
alternatively, the third end (51A) is flush with the first surface (40A) and the fourth end (51B) is flush with the second surface (40B).
4. A microphone assembly as recited in claim 2, wherein,
the cross section of the through hole (43) is in a strip shape, and the length extension direction of the cross section of the through hole (43) faces the geometric center of the vibration sensitive area;
the first electrode (31), the second electrode (51) and the third electrode (71) are respectively matched with the corresponding through holes.
5. A microphone assembly as recited in claim 4, wherein,
the first electrode (31), the second electrode (51), and the third electrode (71) are each in any one of a tooth-like structure, a plate-like structure, and a columnar structure.
6. A microphone assembly as recited in claim 4, wherein,
the plurality of through holes (43) includes a plurality of through hole unit groups (430), each through hole unit group (430) including a first through hole (431), a second through hole (432), and a third through hole (433) sequentially arranged in a circumferential direction of the vibration sensitive area (41);
the first electrode (31) is at least partially arranged in the first through hole (431) in a penetrating mode, the second electrode (51) is at least partially arranged in the second through hole (432) in a penetrating mode, and the third electrode (71) is at least partially arranged in the third through hole (433) in a penetrating mode.
7. The microphone assembly of claim 1, further comprising a first conductor (30), a second conductor (50), and a third conductor (70) stacked on one side of the substrate (10), the first conductor (30) being connected to the first electrode (31), the second conductor (50) being connected to the second electrode (51), the third conductor (70) being connected to the third electrode (71);
wherein the first conductor (30) is located between the substrate (10) and the movable dielectric layer (40) in the thickness direction of the substrate (10), the second conductor (50) is located between the movable dielectric layer (40) and the third conductor (70), and the third conductor (70) is located on a side of the second conductor (50) away from the substrate (10);
the first electrical conductor (30), the second electrical conductor (50), and the third electrical conductor (70) are all located at an edge of the substrate (10).
8. A microphone assembly as recited in claim 7, wherein,
the first conductor (30) is provided with at least one first hollowed-out area (301), the second conductor (50) is provided with at least one second hollowed-out area (501), and the third conductor (70) is provided with at least one third hollowed-out area (701);
wherein, in the thickness direction of the substrate (10), projections of the at least one first hollowed-out area (301), the at least one second hollowed-out area (501), the at least one third hollowed-out area (701), and the back cavity (11) overlap.
9. A microphone assembly as defined in claim 7, further comprising:
a first insulator (20) for supporting the first conductor (30) is provided on a side of the substrate (10) close to the movable dielectric layer (40) in the thickness direction of the substrate (10), and a second insulator (60) for supporting the third conductor (70) is provided between the second conductor (50) and the third conductor (70);
the first insulator (20) and the second insulator (60) are located at the edge of the substrate (10).
10. A microphone assembly as recited in claim 1, wherein,
the movable dielectric layer (40) is a flexible and insulating material.
11. The microphone assembly of claim 10 wherein,
the dielectric constant of the movable dielectric layer (40) is greater than or equal to 2.
12. The microphone assembly of claim 1 wherein the movable dielectric layer (40) further comprises:
a support (420), the support (420) being arranged around the vibration sensitive area (41) and the support (420) being located at an edge of the substrate (10);
at least one elastic beam (421), the at least one elastic beam (421) fixedly connects the vibration sensitive area (41) with the supporting portion (420).
13. A microphone assembly as recited in claim 1, wherein,
the movable dielectric layer (40) is provided with at least one fourth hollowed-out area (44), and the at least one fourth hollowed-out area (44) surrounds the vibration sensitive area (41);
the vibration sensitive area (41) of the movable dielectric layer is in contact with the support structure (180) arranged in the back cavity (11) and fixed on the substrate (10).
14. An electronic device comprising a microphone assembly as claimed in any one of claims 1 to 13.
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| CN202311665898.XA CN117376758B (en) | 2023-12-07 | 2023-12-07 | Microphone assembly and electronic equipment |
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| WO2012017504A1 (en) * | 2010-08-06 | 2012-02-09 | パナソニック株式会社 | Manufacturing method for microphone |
| CN107360526A (en) * | 2016-05-09 | 2017-11-17 | 上海微联传感科技有限公司 | Silicon microphone and its manufacture method |
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