microphone

Abstract

The utility model discloses a microphone, including circuit board and being located on the casing of circuit board, capacitance sensor and ASIC chip, and the casing is connected with circuit board and is enclosed to form the cavity, and capacitance sensor and ASIC chip all are located in the cavity and are mutually electric connection, capacitance sensor includes the support ring of capacitance structure, the support ring of being located on the circuit board to support capacitance structure, and capacitance structure includes the diaphragm and polar plate of split -connected, and the gasket of being located between diaphragm and polar plate, and diaphragm and polar plate interval opposite setting and with ASIC chip electric connection, diaphragm includes the fixed part of vibration part and located vibration part outer periphery, and fixed part is connected with gasket, and the circumference of polar plate is equipped with the gap corresponding with the fixed part of diaphragm. The microphone of the application has the effect of giving consideration to high signal-to-noise ratio and high sensitivity acoustic performance, reduce the volume, and reduce production cost, can reduce the parasitic capacitance between polar plate and diaphragm simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of sound-to-electric conversion technology, and in particular to a microphone. Background Technology

[0002] Condenser microphones offer excellent sound quality and stability, leading to their widespread use and making them a standard feature in audio equipment in consumer electronics. With the proliferation of smartphones, wearable devices, and the development of artificial intelligence, the demands on microphone performance and size are increasing. While traditional condenser microphones, such as electret microphones, have relatively low manufacturing difficulty and cost, miniaturization increases parasitic capacitance, affecting sensitivity and signal-to-noise ratio. MEMS (Micro Electro Mechanical Systems) microphones, on the other hand, have lower parasitic capacitance, offering better sensitivity and signal-to-noise ratio while maintaining a smaller size. However, their capacitors are manufactured using semiconductor technology, resulting in a monolithic structure that is more difficult to process, leading to higher production costs.

[0003] Therefore, under the current technological conditions, how to balance the acoustic performance, size, and production cost of microphones has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0004] In view of this, the present invention provides a microphone to solve the above problems.

[0005] This application provides a microphone, including a circuit board and a housing, a capacitive sensor and an ASIC chip disposed on the circuit board. The housing is connected to the circuit board and encloses a cavity. The capacitive sensor and the ASIC chip are both located in the cavity and are electrically connected to each other.

[0006] The capacitive sensor includes a capacitor structure and a support ring disposed on the circuit board to support the capacitor structure. The capacitor structure includes a diaphragm and an electrode plate that are separately connected, and a spacer disposed between the diaphragm and the electrode plate. The diaphragm and the electrode plate are disposed at a distance from each other and are electrically connected to the ASIC chip.

[0007] The diaphragm includes a vibrating part and a fixed part located on the outer periphery of the vibrating part. The fixed part is connected to the gasket, and the periphery of the electrode plate is provided with a notch corresponding to the fixed part of the diaphragm.

[0008] The microphone provided by this utility model incorporates a capacitive sensor and an ASIC chip inside its cavity. When the diaphragm of the capacitive sensor vibrates under the influence of sound, the distance between the diaphragm and the electrode changes, causing a change in the capacitance value of the capacitor structure. The ASIC chip amplifies the capacitance change signal of the capacitor structure before outputting it, making the microphone's working principle similar to that of a MEMS microphone. This gives it the advantages of high sensitivity and high signal-to-noise ratio acoustic performance, as well as a relatively small size. Furthermore, the diaphragm and electrode of the capacitor structure are separately connected, employing a separate design. Therefore, it can use more conventional manufacturing processes instead of the semiconductor processing technology used in MEMS microphones, which helps reduce production difficulty and thus production costs. Ultimately, the microphone achieves the effect of balancing high signal-to-noise ratio and high sensitivity acoustic performance, reduced size, and lower production costs.

[0009] Furthermore, since parasitic capacitance is formed between the electrode plate and the fixed part of the diaphragm, the parasitic capacitance will reduce the output of the electrical signal, thereby affecting the sensitivity of the microphone. This application provides a notch on the electrode plate, which corresponds to the fixed part of the diaphragm, thereby reducing the area directly opposite the fixed part of the electrode plate and the diaphragm, thereby reducing the parasitic capacitance between the electrode plate and the diaphragm, and further improving the sensitivity of the microphone. Attached Figure Description

[0010] Figure 1 A cross-sectional view of the microphone provided by this utility model;

[0011] Figure 2 A top view of the electrode plate provided by this utility model;

[0012] Figure 3 Simulation results of different opening ratios and sensitivities of acoustic holes on the electrode plate provided by this utility model;

[0013] Figure 4 Simulation results of different thickness gaskets and sensitivity provided by this utility model;

[0014] Figure 5 A cross-sectional view of a microphone with a circular support ring provided by this utility model;

[0015] Figure 6 A cross-sectional view of a microphone provided by this utility model, in which the electrode plate is located between the support ring and the diaphragm;

[0016] Figure 7 A cross-sectional view of a microphone with a mass block on its diaphragm provided by this utility model;

[0017] Figure 8 for Figure 7 The simulation results of the microphone shown are illustrated in the image.

[0018] Figure 9 A cross-sectional view of a microphone with two diaphragms provided for this utility model;

[0019] Figure 10 for Figure 9 The simulation results of the microphone shown are illustrated in the image.

[0020] Figure 11 A cross-sectional view of the electrode plate, anti-stick protrusions, and gasket provided by this utility model;

[0021] Figure 12 A cross-sectional view of a microphone with two capacitive sensors provided by this utility model;

[0022] Figure 13 A top view of a diaphragm with two diaphragm units provided by this utility model;

[0023] Figure 14 A top view of a diaphragm with four diaphragm units provided for this utility model.

[0024] In the diagram: 100, Microphone; 10, Circuit Board; 12, Housing; 14, Capacitive Sensor; 16, ASIC Chip; 18, Cavity; 20, Capacitor Structure; 22, Support Ring; 24, Air Hole; 26, Diaphragm; 28, Electrode Plate; 30, Gasket; 32, Air Gap; 33, Sound Hole; 34, Vibrating Part; 36, Fixing Part; 38, Notch; 39, Adhesive; 40, Conductive Layer; 42, Via; 44, Copper Foil Layer; 46, Clearance; 48, Interconnect Line; 50, Mass Block; 52, Anti-stick Bump; 54, Metal Pad; 56, Diaphragm Unit. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0026] It should be noted that all directional indicators (such as up, down, left, right, front, back, inside, outside, top, bottom, etc.) in the embodiments of this utility model are only used to explain the relative positional relationship between the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0027] It should also be noted that when a component is referred to as "fixed to" or "set on" another component, the component may be directly on the other component or there may be an intervening component present. When a component is referred to as "connected to" another component, it may be directly connected to the other component or there may be an intervening component present.

[0028] Please see Figure 1 A microphone 100 provided in one embodiment of this utility model includes a circuit board 10, a housing 12, a capacitance sensor 14, and an ASIC (Application-Specific Integrated Circuit) chip 16. The housing 12 is connected to the circuit board 10 and encloses a cavity 18. The capacitance sensor 14 and the ASIC chip 16 are disposed on the circuit board 10 and located inside the cavity 18. The capacitance sensor 14 and the ASIC chip 16 are directly or indirectly electrically connected to the circuit board 10, and the capacitance sensor 14 is electrically connected to the ASIC chip 16. When the capacitance value of the capacitance sensor 14 changes under the action of sound, the ASIC chip 16 can convert the high impedance signal of the capacitance sensor 14 into a low impedance signal, amplify the capacitance change signal, and then output it.

[0029] The capacitive sensor 14 includes a capacitor structure 20 and a support ring 22 disposed on the circuit board 10. The capacitor structure 20 is electrically connected to the ASIC chip 16 and is disposed on the support ring 22. The support ring 22 supports the capacitor structure 20, maintaining a certain distance between the capacitor structure 20 and the circuit board 10. The circuit board 10 has an air hole 24. The support ring 22 is annular, and an air cavity is formed inside it. This air cavity is located between the capacitor structure 20 and the circuit board 10. The air hole 24 on the circuit board 10 is connected to the air cavity in the support ring 22, allowing sound waves from outside the microphone 100 to enter the air cavity through the air hole 24 and act on the capacitor structure 20. This causes the capacitance value of the capacitor structure 20 to change under the action of the sound waves, converting the sound signal into an electrical signal.

[0030] The capacitor structure 20 includes a diaphragm 26, an electrode 28, and a spacer 30. The diaphragm 26 and the electrode 28 are spaced apart and opposite to each other, forming the two electrodes of the capacitor structure 20. The spacer 30 is located between the diaphragm 26 and the electrode 28, separating the diaphragm 26 from the electrode 28 to form an air gap 32 between them. When external sound waves reach the diaphragm 26 through the air hole 24 and the air cavity, they will cause the diaphragm 26 to vibrate, resulting in a change in the distance between the diaphragm 26 and the electrode 28. This causes a change in the capacitance value of the capacitor structure 20, and the capacitance change signal is transmitted to the ASIC chip 16.

[0031] The diaphragm 26 and the electrode 28 are connected separately. This separate connection means that the diaphragm 26 and the electrode 28 are not integrally formed, but are formed separately and then connected together by mechanical or chemical bonding methods. In this embodiment, the diaphragm 26 and the electrode 28 are indirectly connected separately via a gasket 30.

[0032] The microphone 100 of this application includes a capacitive sensor 14 comprising a separately connected support ring 22 and a capacitor structure 20, and the capacitor structure 20 further comprises a separately connected diaphragm 26 and an electrode plate 28, thus forming a separate design for the capacitive sensor 14. The diaphragm 26 vibrates under the action of sound waves, causing the capacitance value of the capacitor structure 20 to change. The ASIC performs impedance conversion and amplification on the capacitance change signal, making the working principle of the microphone 100 similar to that of a MEMS microphone. This gives the microphone 100 similar performance to a MEMS microphone, namely, the microphone 100 has the advantages of high signal-to-noise ratio and high sensitivity acoustic performance, as well as small size. However, the capacitor sensor 14 is a split design, rather than the integrated design of a MEMS microphone. Therefore, the components of the capacitor sensor 14 can be made using more conventional materials (such as metal, PCB, LCP resin, etc.) and manufacturing processes (such as electroplating, bonding, adhesive, etc.) and then assembled. It does not require the semiconductor processing technology of MEMS microphones, which helps to reduce production difficulty and thus production costs. Ultimately, the microphone 100 achieves the effect of balancing high signal-to-noise ratio and high sensitivity acoustic performance, reduced size, and reduced production costs.

[0033] Meanwhile, the diaphragm 26 and electrode 28 of the capacitive sensor 14 adopt a separate design, which allows the process parameters of the diaphragm 26 and electrode 28 to be adjusted independently, thereby enabling the performance adjustment of the microphone 100. Furthermore, the diaphragm 26 and electrode 28 can be customized according to actual needs, avoiding problems such as uneven film stress distribution and difficulty in adjusting process parameters caused by the integrated architecture formed by semiconductor processing technology. This is beneficial to improving the production yield and design flexibility of the product. Moreover, the diaphragm 26 and electrode 28 with separate design have a greater thickness than MEMS microphones, which is beneficial to improving the resistance to foreign objects and thus enhancing the reliability of the product.

[0034] In one embodiment, the diaphragm 26 includes a vibrating portion 34 and a fixed portion 36. The vibrating portion 34 is suspended and vibrates under the action of sound waves. The fixed portion 36 is located on the outer periphery of the vibrating portion 34 and is used for fixing, so it cannot vibrate. The pad 30 is connected to the fixed portion 36. The middle portion of the electrode plate 28 is disposed opposite to the vibrating portion 34 of the diaphragm 26, and the capacitance between them is an effective capacitance. This part of the capacitance is used to convert the vibration of the diaphragm 26 into an electrical signal. The edge portion of the electrode plate 28 is disposed opposite to the fixed portion 36 of the diaphragm 26, and a capacitance is also generated between them. This part of the capacitance is an ineffective capacitance, i.e., a parasitic capacitance. The parasitic capacitance will reduce the output of the electrical signal, thereby affecting the sensitivity of the microphone 100.

[0035] Please see Figure 2A notch 38 is provided through the periphery of the electrode plate 28, and the periphery of the electrode plate 28 corresponds to the fixed portion 36 of the diaphragm 26, thus making the notch 38 correspond to the fixed portion 36 of the diaphragm 26. The capacitance value is positively correlated with the area of ​​the two electrodes facing each other; the larger the area of ​​the facing region, the larger the capacitance value. Since the periphery of the electrode plate 28 corresponds to the fixed portion 36 of the diaphragm 26, parasitic capacitance will be generated between them. Providing a notch 38 at the periphery of the electrode plate 28 can reduce the area of ​​the region on the electrode plate 28 facing the fixed portion 36 of the diaphragm 26, thereby reducing parasitic capacitance and further improving the sensitivity of the microphone 100.

[0036] The number of notches 38 can be one or more. In an optional example, the number of notches 38 is multiple, and the multiple notches 38 are arranged at intervals along the circumference of the electrode plate 28. This is beneficial to further reduce the parasitic capacitance between the electrode plate 28 and the diaphragm 26. At the same time, setting multiple relatively small notches 38 is beneficial to maintaining the integrity of the structure compared to setting a single large notch 38, so as to better maintain the mechanical strength of the electrode plate 28.

[0037] The specific shape of the notch 38 is not limited, and it can be circular, semi-circular, elliptical, triangular, or other polygonal. In an alternative example, the notch 38 is semi-circular and extends inward from the outer edge of the electrode 28.

[0038] The projection of the notch 38 onto the diaphragm 26 is located within the fixed portion 36, meaning the projection of the notch 38 along the vibration direction of the diaphragm 26 does not fall into the vibrating portion 34. This prevents the notch 38 from affecting the effective capacitance between the diaphragm 26 and the electrode plate 28, thereby affecting the acoustic performance. It should be noted that the projection of the notch 38 along the vibration direction of the diaphragm 26 can be entirely located within the fixed portion 36 of the diaphragm 26, or partially located within the fixed portion 36 and partially located outside the diaphragm 26, as long as it does not fall into the vibrating portion 34.

[0039] At least part of the notch 38 contains adhesive (not shown) that connects the electrode 28 and the gasket 30, so that the notch 38 can not only reduce the parasitic capacitance between the diaphragm 26 and the electrode 28, but also accommodate the adhesive to connect the electrode 28 and the gasket 30.

[0040] An air gap 32 is formed between the electrode plate 28 and the diaphragm 26. The inner wall of the notch 38 does not extend beyond the side of the gasket 30 near the air gap 32. That is, the notch 38 is spaced a certain distance from the air gap 32 and is not connected to the air gap 32, so as to prevent the adhesive from entering the air gap 32 through the notch 38 when the adhesive is applied into the notch 38.

[0041] Optionally, the gasket 30 is annular, the air gap 32 is located inside the gasket 30, and the inner wall of the notch 38 does not extend beyond the radial inner wall of the gasket 30. In an optional example, the outer edge of the gasket 30 is flush with the outer edge of the electrode plate 28, and the radial depth of the notch 38 is less than the radial dimension of the gasket 30, thereby spacing the notch 38 and the air gap 32 by a certain distance.

[0042] The electrode plate 28 is provided with a plurality of acoustic holes 33, which penetrate the electrode plate 28 along the thickness direction and are connected to the air gap 32, so that airflow can pass through the acoustic holes 33 between the air gap 32 and the outside of the electrode plate 28 to reduce the damping effect when the diaphragm 26 vibrates. Optionally, there are multiple acoustic holes 33, which are arranged at intervals.

[0043] Please see Figure 3 The aperture ratio of the sound holes 33 on the electrode plate 28 is greater than 10%. The aperture ratio refers to the percentage of the total area of ​​all sound holes 33 on the electrode plate 28 to the area of ​​the electrode plate 28. The aperture ratio affects the damping and thus the frequency response of the microphone 100. If the aperture ratio is too small, the high-frequency attenuation of the frequency response of the microphone 100 will be more serious. Making the aperture ratio of the sound holes 33 on the electrode plate 28 greater than 10% can effectively reduce the high-frequency attenuation problem caused by the small aperture ratio.

[0044] Please see Figure 4 In one embodiment, the thicknesses of the electrode plate 28, the spacer 30, and the diaphragm 26 gradually decrease; that is, the thickness of the electrode plate 28 is greater than the thickness of the spacer 30, and the thickness of the spacer 30 is greater than the thickness of the diaphragm 26. The electrode plate 28 is made of a rigid material such as metal and does not participate in vibration, but it requires a certain degree of rigidity for support, hence its relatively large thickness. The diaphragm 26 needs to vibrate, and if its thickness is too large, it will affect its elasticity, thus affecting the vibration of the diaphragm 26; therefore, its thickness needs to be relatively small. The thickness of the spacer 30 has a significant impact on the sensitivity of the microphone 100. The smaller the thickness of the spacer 30, the smaller the gap between the diaphragm 26 and the electrode plate 28, and the higher the sensitivity of the microphone 100. However, at the same time, the high-frequency damping will also increase, leading to high-frequency attenuation of the frequency response. Therefore, the thickness of the spacer 30 cannot be too small; its thickness is controlled between that of the electrode plate 28 and the diaphragm 26 to achieve a balance between sensitivity and high-frequency attenuation of the frequency response.

[0045] If the thickness of the diaphragm 26 is too large, it will affect the vibration, while if it is too small, it will affect the mechanical strength. In an optional example, the thickness of the diaphragm 26 is within 3 μm, for example, between 1 μm and 3 μm, in order to achieve a balance between elasticity and mechanical strength.

[0046] In one embodiment, the inner surface (the surface near the cavity 18) and the outer surface (the surface away from the cavity 18) of the circuit board 10 are respectively provided with a plurality of pads. The ASIC chip 16 is electrically connected to the pads on the inner surface of the circuit board 10, and the external device is electrically connected to the pads on the outer surface of the circuit board 10.

[0047] The specific types of pads can be set according to the type of microphone 100. For example, when the microphone 100 is an analog microphone 100, VDD, OUTPUT, and GND pads can be set on the outer surface of the circuit board 10, and VDD, OUTPUT, and GND pads corresponding to the interconnects 48 of the ASIC chip 16 can be set on the inner surface of the circuit board 10. When the microphone 100 is a digital microphone 100, VDD, DATA, LR, CLK, and GND pads can be set on the outer surface of the circuit board 10, and VDD, DATA, LR, CLK, and GND pads corresponding to the interconnects 48 of the ASIC can be set on the inner surface of the circuit board 10.

[0048] Please see Figure 1 The support ring 22 is a hollow ring structure, which is fixed to the circuit board 10 by adhesive 39, which surrounds the outer periphery of the support ring 22. The material of the support ring 22 can be high-temperature resistant insulating materials such as LCP (Liquid Crystal Polymer) resin, ceramic, or glass. A conductive layer 40 is provided on its surface, which can be formed by processes such as bonding, electroplating, brushing, or vacuum deposition. The diaphragm 26 or electrode 28 is electrically connected to the conductive layer 40 on the support ring 22, and the conductive layer 40 is electrically connected to the ASIC chip 16 through interconnecting lines 48, thereby achieving electrical connection between the diaphragm 26 or electrode 28 and the ASIC chip 16. Optionally, a stepped structure is formed on the outer side of the support ring 22, and the conductive layer 40 is attached to the stepped structure.

[0049] Please see Figure 5 In other embodiments, the support ring 22 is made of the same material as the circuit board 10 and is circular. A through-hole 42 is provided through the support ring 22, and conductive material is disposed within the through-hole 42 and connected to the copper foil layer 44 within the circuit board 10 via solder or silver paste. The copper foil layer 44 is located at the middle position in the thickness direction of the circuit board 10. An allowance 46 is provided on the inner surface of the circuit board 10, extending to the copper foil layer 44 to expose a portion of the copper foil layer 44. Electrodes can be disposed on the exposed copper foil layer 44. The ASIC chip 16 is electrically connected to the electrodes on the copper foil layer 44 via interconnect lines 48 to achieve electrical connection between the ASIC chip 16 and the circuit board 10.

[0050] The specific relative positional relationship between the electrode 28 and the diaphragm 26 is not limited. The electrode 28 can be positioned above the diaphragm 26, or the diaphragm 26 can be positioned above the electrode 28, as long as the electrode 28 and the diaphragm 26 are arranged opposite each other to form the two electrodes of the capacitor structure 20. In one embodiment, such as... Figure 1 As shown, the diaphragm 26 is disposed on the support ring 22 and electrically connected to the conductive layer 40. The diaphragm 26 is electrically connected to the ASIC chip 16 through the conductive layer 40. The spacer 30 and the electrode plate 28 are located on the side of the diaphragm 26 away from the support ring 22. In another embodiment, as... Figure 6 As shown, the electrode plate 28 is disposed on the support ring 22 and electrically connected to the conductive layer 40. The electrode plate 28 is indirectly electrically connected to the ASIC chip 16 through the conductive layer 40. The gasket 30 and the diaphragm 26 are located on the side of the electrode plate 28 away from the support ring 22. The ASIC chip 16 is electrically connected to the conductive ring on the diaphragm 26.

[0051] In one embodiment, the diaphragm 26 includes an elastic diaphragm and a metal layer attached to the elastic diaphragm, i.e., the diaphragm 26 has a double-layer structure. For example, a layer of nickel is vacuum-plated on the lower surface of a PPS (Polyphenylene Sulfide) film or a PET (Polyethylene Terephthalate) film. The elastic diaphragm is elastic and is used to vibrate under the action of sound waves. The metal layer is conductive and is used to act as an electrode of the capacitor structure 20. The metal layer is electrically connected to the conductive layer 40 on the support ring 22.

[0052] In other embodiments, the diaphragm 26 may also be a single-layer structure, that is, the diaphragm 26 is a conductive film with conductive function, such as graphene, polycrystalline silicon, monocrystalline silicon, aluminum foil or stainless steel.

[0053] A spacer 30 is positioned between the diaphragm 26 and the electrode 28, with both sides of the spacer 30 connected to the diaphragm 26 and the electrode 28 respectively, thus assembling and fixing the three together. The spacer 30 can be made of a high dielectric constant insulating material, such as PET film, or it can have a double-sided adhesive structure, which can both separate the diaphragm 26 and the electrode 28 and fix them together.

[0054] The gasket 30 and the electrode plate 28 can be formed separately and then connected, or they can be formed as one piece. For example, the gasket 30 can be formed on the surface of the electrode plate 28 by processes such as pasting, electroplating, brushing or vacuum coating, or it can be formed by growing an oxide layer on the surface of the electrode plate 28 and etching the oxide layer.

[0055] Electrode 28 serves as another electrode of capacitor structure 20 and can be electrically connected to ASIC chip 16 via interconnect 48. Electrode 28 can be made of metal and be a single metal plate. Alternatively, electrode 28 can be composed of a PCB board and metal layers on the upper and lower surfaces of the PCB board, with the metal layers on the upper and lower surfaces electrically connected through metallized holes. Alternatively, electrode 28 can also be achieved by growing a metal plating layer on a non-metallic surface, such as growing a metal plating layer on the surface of high-temperature resistant insulating materials such as LCP resin, ceramics, or glass.

[0056] In other embodiments, the surface of the electrode plate 28 is provided with an electret material layer. After polarization, the electret material layer carries an electret charge. In this case, the electrode plate 28 does not need to lead out electrodes and be electrically connected to the ASIC chip 16 through the interconnect line 48, which helps to simplify the internal structure of the microphone 100.

[0057] The housing 12 is disposed on one side of the circuit board 10 and is soldered to the ground pad of the circuit board 10 using solder paste. The housing 12 is fixed to the circuit board 10 by soldering, which can effectively avoid mechanical stress damage compared to the edge-rolling process of the housing 12. In addition, the housing 12 can also be provided with vents 24, so that the sound waves from outside the microphone 100 can enter the cavity 18 through the vents 24 on the housing 12 and propagate to the capacitor structure 20.

[0058] Please see Figure 7 and Figure 8 In one embodiment, the diaphragm 26 is located between the electrode plate 28 and the support ring 22. The vibrating portion 34 of the diaphragm 26 is provided with a mass block 50, which is located on the side of the diaphragm 26 away from the electrode plate 28 and inside the support ring 22. When the diaphragm 26 vibrates, the mass block 50 vibrates along with the diaphragm 26. Therefore, setting a mass can increase the overall mass of the vibration system, thereby increasing the inertia of the vibration system and making the microphone 100 more sensitive to low-frequency vibrations, thus realizing the function of vibration pickup.

[0059] The mass block 50 can be fixed to the diaphragm 26 by adhesive, or it can be formed by electroplating a metal block on the surface of the diaphragm 26.

[0060] Please see Figure 9 and Figure 10In one embodiment, the capacitor structure 20 includes two diaphragms 26 and an electrode 28, with the electrode 28 located between the two diaphragms 26, and a spacer 30 is provided between each diaphragm 26 and the electrode 28 to separate them. Capacitance is generated between each diaphragm 26 and the electrode plate 28. When external sound waves enter the cavity 18, both diaphragms 26 vibrate. When the two diaphragms 26 vibrate, the capacitance between the electrode plate 28 and the two diaphragms 26 changes. The two diaphragms 26 vibrate in the same direction, so the distance between one diaphragm 26 and the electrode plate 28 decreases, and the capacitance between the diaphragm 26 and the electrode plate 28 increases. The distance between the other diaphragm 26 and the electrode plate 28 increases, and the capacitance decreases. The electrical signals output by the two diaphragms 26 are out of phase. The two out-of-phase electrical signals are simultaneously input into the ASIC chip 16 and differentially move. This reduces noise and improves the sensitivity and signal-to-noise ratio of the microphone 100. Moreover, the two diaphragms 26 sandwich the electrode plate 28 in the middle, which can effectively prevent foreign objects from entering the air gap 32 and causing abnormal acoustic performance.

[0061] Understandably, the two diaphragms 26 can be electrically connected to the ASIC chip 16 via interconnect 48, or a conductive element can be provided on the outside of the capacitor structure 20, with the two diaphragms 26 electrically connected to the conductive element, and the conductive element then electrically connected to the ASIC chip 16 via interconnect 48.

[0062] In other embodiments, the capacitor structure 20 may also include two plates 28 and a diaphragm 26, with the diaphragm 26 located between the two plates 28. Each plate 28 and the diaphragm 26 can generate capacitance. When the diaphragm 26 vibrates, the distance between the diaphragm 26 and one of the plates 28 decreases, and the distance between the diaphragm 26 and the other plate 28 increases. Differential output can also be achieved to improve the sensitivity and signal-to-noise ratio of the microphone 100.

[0063] Please see Figure 11 In one embodiment, the electrode plate 28 has anti-sticking protrusions 52 on the side near the diaphragm 26. The anti-sticking protrusions and the gasket 30 are located on the same side of the electrode plate 28, and the height of the anti-sticking protrusions is less than the thickness of the gasket 30, thereby creating a certain distance between the anti-sticking protrusions and the diaphragm 26. The anti-sticking protrusions 52 can prevent the diaphragm 26 from sticking together with the electrode plate 28 when the vibration amplitude is too large, thus preventing the diaphragm 26 from vibrating normally.

[0064] Optionally, the electrode 28, the gasket 30, and the anti-stick protrusion are integrally formed, while the diaphragm 26 is separately connected to the gasket 30 on the electrode 28, which helps improve the consistency of the capacitor structure 20. During production, the electrode 28 can be fabricated using semiconductor materials such as monocrystalline silicon or polycrystalline silicon. The thickness of the electrode 28 can be between 0.01 mm and 0.5 mm. Then, a layer of silicon dioxide is grown on one side or opposite sides of the electrode 28. The thickness of the silicon dioxide can be between 2 μm and 60 μm. A sound hole 33 is then etched, penetrating the electrode 28 and the silicon dioxide layer. Excess silicon dioxide is removed through etching, leaving the portion forming the gasket 30 and the anti-stick protrusion. The thickness of the gasket 30 is the same as the thickness of the silicon dioxide layer, while the thickness of the anti-stick protrusion is less than the thickness of the silicon dioxide layer. Using an integral molding method not only ensures the reliability of the connection between the anti-stick protrusion and the gasket 30 and the electrode 28, but also allows for a thinner gasket 30.

[0065] In an alternative example, when etching away excess silicon dioxide layer, a portion of the edge of electrode 28 may be exposed, and a metal pad 54 may be generated at the exposed edge. The ASIC chip 16 is connected to the metal pad 54 via interconnect 48, thereby achieving the connection between electrode 28 and ASIC chip 16.

[0066] Please see Figure 12 In one embodiment, the housing 12 contains two capacitive sensors 14 spaced apart. An ASIC chip 16 is located between the two capacitive sensors 14, and both capacitive sensors 14 are electrically connected to the ASIC chip 16. Air vents 24 are provided on the circuit board 10 corresponding to the two capacitive sensors 14. The ASIC chip 16 is a differential chip, which provides the bias voltage required for operation to the capacitive sensors 14 located on both sides of it, and then inputs the capacitance changes of the two capacitive sensors 14 to the differential input terminal.

[0067] The arrangement direction of the two capacitive sensors 14 is defined as the first direction, and the direction perpendicular to the first direction is defined as the second direction. The first and second directions form a rectangular coordinate system. The first direction can be the X-axis (0° to 180°), and the second direction can be the Y-axis (0° to 180°). When the sound wave propagates along the first direction, the distance between the two capacitive sensors 14 and the sound source is different. Therefore, the sound wave will pass through the two capacitive sensors 14 one after the other, resulting in different sound pressure levels, phase differences, and time differences for the sound waves from the same sound source reaching the two capacitive sensors 14. This generates two different sound pressure signals, which are input to the intermediate differential chip. The differential chip performs differential processing on the two signals internally and outputs them, giving the output electrical signal directional characteristics. At this time, the microphone 100 has the highest sensitivity in the first direction and the lowest sensitivity in the second direction, giving the microphone 100 a directional sound pickup effect, suppressing environmental noise, and making the microphone 100 suitable for noisy environments.

[0068] The air holes 24 on the circuit board 10 may not have damping meshes. In this case, the pickup pattern of the microphone 100 is in the shape of an "8", and the microphone 100 is a figure-eight pickup microphone 100. Alternatively, different damping meshes may be set at the air holes 24 corresponding to the two capacitors. In this case, the pickup pattern of the microphone 100 is in the shape of a heart.

[0069] Please see Figure 13 and Figure 14 In one embodiment, the diaphragm 26 includes multiple diaphragm units 56 arranged in an array. Each diaphragm unit 56 is spaced apart from the electrode plate 28, meaning that capacitance is generated between each diaphragm unit 56 and the electrode plate 28. The sensitivity of the microphone 100 is mainly determined by the total area of ​​the diaphragm 26. A larger area results in lower rigidity, greater vibration amplitude under sound waves, greater capacitance change, and higher sensitivity. Conversely, the high-frequency bandwidth of the microphone 100 is mainly determined by the rigidity of the diaphragm 26. Lower rigidity leads to lower resonant frequency and narrower high-frequency bandwidth. To balance the sensitivity and high-frequency bandwidth of the microphone 100, the diaphragm 26 is made to include multiple independent diaphragm units 56, effectively dividing a large diaphragm 26 into multiple smaller diaphragms 26. With the total area remaining constant, the rigidity of the diaphragm units 56 is enhanced, thereby increasing the high-frequency bandwidth without reducing sensitivity.

[0070] Understandably, array arrangement can refer to an arrangement forming multiple rows and columns, or multiple rows and a single column, or a single row and multiple columns. For example... Figure 13 As shown, when there are two diaphragm units 56, the two diaphragm units 56 are arranged in one row and two columns; as Figure 14 As shown, when there are four diaphragm units 56, the four diaphragm units 56 are arranged in two rows and two columns.

[0071] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A microphone, characterized in that, The device includes a circuit board and a housing, a capacitive sensor, and an ASIC chip disposed on the circuit board. The housing is connected to the circuit board and encloses a cavity. The capacitive sensor and the ASIC chip are both located in the cavity and are electrically connected to each other. The capacitive sensor includes a capacitor structure and a support ring disposed on the circuit board to support the capacitor structure. The capacitor structure includes a diaphragm and an electrode plate that are separately connected, and a spacer disposed between the diaphragm and the electrode plate. The diaphragm and the electrode plate are disposed at a distance from each other and are electrically connected to the ASIC chip. The diaphragm includes a vibrating part and a fixed part located on the outer periphery of the vibrating part. The fixed part is connected to the gasket, and the periphery of the electrode plate is provided with a notch corresponding to the fixed part of the diaphragm.

2. The microphone according to claim 1, characterized in that, The projection of the notch on the diaphragm is located within the fixed portion.

3. The microphone according to claim 1, characterized in that, At least a portion of the notch contains an adhesive that connects the electrode plate and the gasket.

4. The microphone according to claim 3, characterized in that, An air gap is formed between the electrode plate and the diaphragm, and the inner wall of the notch does not extend beyond the side of the gasket closest to the air gap.

5. The microphone according to claim 1, characterized in that, The number of the notches is multiple, and the multiple notches are arranged at intervals along the circumference of the electrode plate.

6. The microphone according to claim 1, characterized in that, The thickness of the electrode plate is greater than the thickness of the gasket, and the thickness of the gasket is greater than the thickness of the diaphragm.

7. The microphone according to claim 1, characterized in that, The electrode plate is provided with a through-hole, which corresponds to the vibrating part of the diaphragm, and the opening ratio of the through-hole on the electrode plate is greater than 10%.

8. The microphone according to claim 1, characterized in that, The electrode plate has anti-sticking protrusions on the side near the diaphragm, and the anti-sticking protrusions, the gasket, and the electrode plate are integrally formed.

9. The microphone according to any one of claims 1-8, characterized in that, The number of diaphragms is two, and the electrode plate is located between the two diaphragms; or... The number of electrodes is two, and the diaphragm is located between the two electrodes; or... The number of capacitive sensors is two, the ASIC chip is a differential chip, the differential chip is located between the two capacitive sensors, and the two capacitive sensors are electrically connected to the ASIC chip respectively. The circuit board is provided with air holes corresponding to the two capacitive sensors respectively.

10. The microphone according to any one of claims 1-8, characterized in that, The diaphragm comprises multiple diaphragm units arranged in an array, each of which is spaced apart from the electrode plate; or, The diaphragm is located between the electrode plate and the support ring, and the vibrating part of the diaphragm has a mass block on the side away from the electrode plate.

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