Vibration assembly and electret microphone

Abstract

The utility model provides a vibration assembly and an electret microphone. The vibration assembly comprises a vibration ring, a vibrating diaphragm, a gasket and a back pole plate which are sequentially arranged in an overlapped mode. The vibrating diaphragm comprises an elastic diaphragm and a conductive layer arranged on the elastic diaphragm. The vibrating ring comprises a conductive part, the conductive part comprises inner edge notches which are arranged at intervals in the circumferential direction of the inner edge of the vibrating ring, the vibrating diaphragm corresponding to the inner edge notches forms an insulating area, and the vibrating diaphragm in the insulating area is insulated from the vibrating diaphragm in a non-insulating area. According to the vibration assembly and the electret microphone provided by the invention, the parasitic capacitance can be effectively reduced, the sensitivity is improved, and the tone quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of sound-generating devices, and in particular to a vibration component and an electret microphone. Background Art

[0002] An electret microphone, also known as an electret condenser microphone, operates on the following principle: two parallel metal plates spaced apart in space form a capacitor. For example, a hollow, ring-shaped plastic spacer, placed between the back plate and the conductive coating of the diaphragm, forms the core acoustic-to-electrical conversion component of the electret condenser microphone.

[0003] Electret condenser microphones, thanks to their low cost and excellent performance, have been widely used and hold a significant market share. With the increasing popularity of smart devices such as smartphones, wearables, and security surveillance systems, as well as the development of artificial intelligence, the demand for high-performance sound pickup is becoming increasingly urgent. However, traditional electret microphones contain a large amount of parasitic capacitance, which significantly reduces the microphone's sensitivity, degrades the sound quality, and impacts the user experience. Summary of the Invention

[0004] Based on this, the present application provides a vibration component and an electret microphone to improve the problem of low sensitivity and poor sound quality of the microphone caused by large parasitic capacitance.

[0005] To achieve the above objectives, the technical solution of the embodiment of the present application is implemented as follows:

[0006] On the one hand, an embodiment of the present application provides a vibration assembly for an electret microphone, comprising a vibration ring, a vibration membrane, a gasket, and a back plate stacked in sequence; the vibration membrane comprises an elastic film and a conductive layer provided on the elastic film;

[0007] The vibration ring includes a conductive part, which includes inner edge notches arranged at intervals along the inner edge of the vibration ring. The vibration membrane corresponding to the inner edge notches forms an insulating area, and the vibration membrane in the insulating area is insulated from the vibration membrane in the non-insulating area.

[0008] In one embodiment, the vibration ring is entirely made of conductive metal; or, the vibration ring includes a base material portion and the conductive portion, and the conductive portion is at least partially located on a surface of the base material portion close to the diaphragm;

[0009] The inner edge notch is formed by the inner side wall of the vibration ring being recessed toward the outer side wall.

[0010] In one embodiment, a protrusion is formed between every two adjacent inner edge notches;

[0011] The vibration ring includes a base material portion and the conductive portion, wherein the conductive portion is at least partially located on the surface of the base material portion close to the vibration membrane, and the inner edge notch is formed by the inner edge side wall corresponding to the protruding portion being recessed toward the outer edge side wall of the base material portion.

[0012] In one embodiment, the cross-sectional area of ​​the inner edge notch is 0.1-4 times the surface area of ​​the conductive portion on a side close to the diaphragm.

[0013] In one embodiment, a plurality of bosses are provided at intervals on the periphery of the back plate, and the bosses are fixedly connected to the gasket.

[0014] In one embodiment, the bosses and the inner edge notches are arranged alternately.

[0015] In one embodiment, the circumferential dimension of the outer peripheral wall of the back plate between two adjacent bosses is not greater than the circumferential dimension of the inner hole of the gasket.

[0016] In one embodiment, the circumferential dimension of the outer wall of the back plate between two adjacent bosses is smaller than the circumferential dimension of the inner hole of the gasket, and the back plate is provided with a vent hole only in the middle position.

[0017] In one embodiment, the vibration assembly further comprises a pole ring, and a surface of the pole ring away from the back plate is provided with a plurality of protrusions spaced circumferentially.

[0018] On the other hand, an embodiment of the present application provides an electret microphone, comprising the vibration component as described above.

[0019] The present application has at least the following beneficial effects: the vibration assembly provided in the embodiment of the present application has a conductive portion of the vibration ring provided with an inner edge notch, and the diaphragm provided with an insulating area corresponding to the inner edge notch, so that the parasitic capacitance between the back plate and the diaphragm is reduced, thereby effectively improving the sensitivity of the microphone, and improving the sound quality of the electret microphone and the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of a conventional electret microphone.

[0021] Figure 2 Schematic diagram illustrating the parasitic capacitance generated by a conventional electret microphone.

[0022] Figure 3 Schematic diagram of the exploded structure of a vibration assembly according to an embodiment of the present application.

[0023] Figure 4 This is a schematic diagram of the exploded structure of a vibration assembly according to another embodiment of the present application.

[0024] Figure 5 for Figure 3 Schematic diagram of the structure of the vibration ring.

[0025] Figure 6 This is a structural diagram of a vibration ring according to another embodiment of the present application.

[0026] Figure 7 FIG. 1 is a structural diagram of a vibration ring according to another embodiment of the present application.

[0027] Figure 8 for Figure 3 Schematic diagram of the structure of the diaphragm.

[0028] Figure 9 for Figure 4 Schematic diagram of the cross-sectional structure of the vibration component.

[0029] Figure 10 for Figure 4 Schematic diagram of the overall structure of the vibration component.

[0030] Figure 11 FIG. 1 is a schematic diagram of the exploded structure of an electret microphone according to an embodiment of the present application.

[0031] Figure 12 FIG. 1 is a schematic diagram of the exploded structure of an electret microphone according to another embodiment of the present application.

[0032] Figure 13 for Figure 12 Schematic diagram of the structure of the polar ring.

[0033] Figure 14 FIG. 1 is a structural diagram of an electret microphone according to another embodiment of the present application.

[0034] The meanings of the reference numerals in the accompanying drawings are as follows:

[0035] 1. Circuit board; 11. Conductive spring; 2. Housing; 3. Gasket; 4. Dust screen; 5. Diaphragm; 51. Elastic membrane; 52. Conductive layer; 6. Back plate; 61. Vent; 62. Boss; 7. Vibration ring; 71. Raised portion; 72. Inner edge notch; 8. Cavity ring; 9. Pole ring cavity; 91. Damping net; 10. Pole ring; 101. Protrusion. DETAILED DESCRIPTION

[0036] The technical solution of this application is further elaborated in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit the implementation of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In the description of this application, it should be understood that the terms "center," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting this application. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0039] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0040] like Figure 1 The figure shows the internal structure of a conventional electret microphone, which includes a shell 2. A dust net 4 and a circuit board 1 are provided at both ends of the shell 2. The dust net 4 can be connected and fixed to the outer surface of the shell 2 by means of double-sided tape or the like. A sound hole is provided at the bottom of the shell 2, and a vibration component is also provided inside. The vibration component includes a vibration ring 7, a vibration membrane 5, a gasket 3, a back plate 6 and a pole ring 10 stacked in sequence from one end of the dust net 4 to one end of the circuit board 1. The outer sleeve of the pole ring 10 is provided with a cavity ring 8. The vibration ring 7 is conductive to the shell 2, and the pole ring 10 is conductive to the circuit board 1. The core sound-to-electricity conversion components of the electret microphone in the current industry are as follows: Figure 2As shown in the figure, the capacitance between the backplate 6 and the diaphragm 5 consists of two parts. One is the capacitance formed by the area S of the backplate 6 corresponding to the vibrating portion of the diaphragm 5, called the effective capacitance Cmic. This portion of capacitance converts vibration into an electrical signal. The other is the ineffective capacitance, or parasitic capacitance, corresponding to the ineffective area △S = Sb-S in the figure. The capacitance corresponding to the ineffective area is Cs. The presence of this parasitic capacitance reduces the output signal, thereby reducing the sensitivity and signal-to-noise ratio of the microphone. The above is only an example of the principle of the generation of a part of the parasitic capacitance of the electret microphone. There are other parasitic capacitances in the electret microphone, which are not listed here.

[0041] See also Figure 3 and Figure 4 The embodiment of the present application provides a vibration assembly for an electret microphone, wherein the vibration assembly includes a vibration ring 7, a diaphragm 5, a gasket 3, and a back plate 6 connected in sequence. The diaphragm 5 includes an elastic film 51 and a conductive layer 52 provided on the elastic film 51.

[0042] Vibration ring 7 includes a conductive portion, which includes inner edge notches 72 spaced circumferentially along the periphery of vibration ring 7. A raised portion 71 is formed between each two adjacent inner edge notches 72. The diaphragm 5 forms an insulating region corresponding to the inner edge notches 72. The insulating region of the diaphragm 5 is insulated from the non-insulating region of the diaphragm 5.

[0043] like Figure 3 As shown, in some embodiments, the entire vibration ring 7 is made of conductive metal, that is, the vibration ring 7 is the conductive part, and the conductive metal can be, for example, ordinary steel or stainless steel. The vibration ring 7 is a ring-shaped member, and the specific cross-sectional shape is not limited, for example, it can be a square ring or a circular ring (such as Figure 5 As shown). In conventional technology, the inner hole of the vibration ring 7 can be an integral square hole or a circular hole. In this embodiment, in order to reduce the parasitic capacitance generated at the vibration ring 7, the inner edge structure of the vibration ring 7 is improved. A plurality of inner edge notches 72 are made on the side wall of the inner edge of the vibration ring 7. The inner edge notches 72 are recessed from the inner edge side wall of the vibration ring 7 to the outer edge side wall relative to the protrusion 71, effectively reducing the area of ​​the parasitic capacitance. When making the vibration ring 7 of this embodiment, the material at the inner edge notch 72 can be removed from the vibration ring of the traditional structure. The inner edge notch 72 specifically refers to the portion (i.e., the inner edge notch 72) of the inner hole of the vibration ring 7 that is recessed inward (inward here refers to the interior of the vibration ring 7, that is, from the inner hole side wall to the outer circular side wall). Figure 5 The part surrounded by the dotted line).

[0044] In some embodiments, the vibration ring 7 may also include a substrate portion and a conductive portion. The substrate portion may be made of, for example, non-conductive plastic, ceramic, or a substrate of a PCB (printed circuit board) such as FR-4. A layer of conductive material may be plated on all or part of the surface of the substrate portion. The conductive material may be, for example, copper, to form a conductive portion. At least the entire surface of the substrate portion close to the diaphragm 5 is provided with a conductive portion so that the conductive portion can be electrically conductive with the conductive layer 52 of the diaphragm 5. The conductive portion must also be able to be electrically conductive with the housing 2 of the electret microphone. For example, the conductive portion may be plated on the entire surface of the substrate portion so that the conductive portion can be electrically conductive with the conductive layer 52 of the diaphragm 5 and at the same time, can be electrically conductive with the housing 2. At this time, since the base material is a non-conductive material, there are two ways to form the inner edge notch 72 structure. The first method is the same as the method described above for the vibration ring 7 made entirely of conductive metal, which is to completely remove the structure of the vibration ring 7 at the inner edge notch 72, removing both the conductive portion and the base material therein, so that the inner edge notch 72 is formed by the inner sidewall of the vibration ring 7 being recessed toward the outer sidewall. When the inner edge notch 72 is formed by the overall removal method for the vibration ring 7 of the two structures described above, the removal area of ​​the inner edge notch 72 needs to be controlled to a certain extent. The larger the proportion of the area occupied by the inner edge notch 72 on the surface of the vibration ring 7, the greater the degree of reduction in parasitic capacitance. However, the larger the proportion of the area occupied by the inner edge notch 72, the weaker the overall structural strength of the vibration ring 7, which may affect the performance stability of the microphone product. Specifically, the area removed at the inner edge notch 72 can be controlled to be 10%-80% of the original large surface area of ​​the vibration ring (the surface area on the side close to the diaphragm 5 when the inner edge notch 72 is not formed). That is, the cross-sectional area of ​​the inner edge notch 72 accounts for about 0.1-4 times the area of ​​the actual large surface area of ​​the vibration ring 7 (the surface of the vibration ring 7 on the side close to the diaphragm 5 in this embodiment). The contour track shape of the inner edge notch 72 is not limited and can be any shape, such as Figure 6 and Figure 7 As shown, there are two structures of vibration rings 7 with inner edge notches 72 of different shapes. The number of inner edge notches 72 can also be selected according to actual needs. There is another way to implement the inner edge notches 72 of this embodiment. This method does not require removing the material corresponding to the base material part, but only removes the material at the conductive part. This is beneficial to improving the strength of the vibration ring 7, thereby improving the stability of the overall structure and performance of the electret microphone, and the effect of reducing parasitic capacitance is the same as that of the first implementation method. In this embodiment, when making the structure of the inner edge notch 72, the conductive material can be first plated on the surface of the base material part close to the diaphragm 5, and then the conductive material corresponding to the inner edge notch 72 can be removed, or part of the conductive material can be removed along the peripheral contour of the inner edge notch 72 so that the conductive material at the inner edge notch 72 forms an island that is not conductive to the conductive part.

[0045] like Figure 8As shown, the diaphragm 5 may specifically include an elastic membrane 51 and a conductive layer 52 disposed on the surface of the elastic membrane 51. The elastic membrane 51 may be a plastic film made of materials such as PPS (polyphenylene sulfide) or PET (polyester resin), with a thickness of approximately 2 μm. The conductive layer 52 is plated with a conductive metal, such as nickel. The conductive layer 52 is fixed to and electrically connected to the conductive portion of the diaphragm 7. The conductive material at the location corresponding to the conductive layer 52 and the inner edge notch 72 can be removed to prevent electrical conduction between the diaphragm 5 at the location corresponding to the inner edge notch 72 and the diaphragm 5 provided with the conductive layer 52. Specifically, the conductive material at the location corresponding to the inner edge notch 72 can be removed entirely, leaving only the elastic film 51. Alternatively, the circumferential edge of the conductive material corresponding to the location can be removed along the edge contour of the inner edge notch 72, forming an island of conductive material at that location (the remaining conductive material here is not the conductive layer 52 referred to in this embodiment, and is not used for conductive purposes), preventing the remaining conductive material from conducting with the conductive layer 52. Specific removal methods can include laser etching. It should be noted that when removing the conductive material, the integrity of the elastic film 51 should be maintained, and the elastic film 51 should not be removed. The conductive material at the locations corresponding to the inner edge notch 72 of the diaphragm 5 and the vibrating ring 7 should be removed in a corresponding manner to avoid overlapping and loss of insulation. It is best to remove the conductive material at the inner edge notch 72 entirely.

[0046] The gasket 3 is made of insulating material, such as PET (polyester resin), etc. The gasket 3 is a hollow annular gasket, and its specific shape is similar to that of the vibration ring 7.

[0047] The back plate 6 includes an electret material layer and a conductive plate, which are connected to each other. The conductive plate can be made of, for example, stainless steel or nickel-plated copper. The electret material layer can be made of, for example, PTFE (polytetrafluoroethylene) or FEP (polyfluoroethylene propylene), and is used to store charge. Ventilation holes 61 are provided on the back plate 6. The number and area of ​​vents 61 can be selected based on actual needs. Excessive vents 61 can affect the polarization electric field strength of the back plate 6 and also have a certain impact on the sound quality.

[0048] like Figure 9 and Figure 10As shown, in order to further reduce the existence of parasitic capacitance, a plurality of bosses 62 can be provided on the back plate 6, and the bosses 62 are fixedly connected to the gasket 3. The circumferential dimension of the outer peripheral wall of the back plate 6 between two adjacent bosses 62 is not greater than the circumferential dimension of the inner hole of the gasket 3. That is, a depression is formed between the two adjacent bosses 62 of the back plate 6, and the radial dimension of the depression is equal to the inner diameter dimension of the gasket 3, or smaller than the inner diameter dimension of the gasket 3, so that the vertical projection of the outer peripheral contour of the depression on the surface of the gasket 3 is located within the range of the inner hole of the gasket 3. The area of ​​the overlapping part of the back plate 6 and the vibration ring 7 is reduced, thereby reducing the parasitic capacitance and achieving the purpose of improving sensitivity. When the radial dimension of the recess is smaller than the inner diameter of the gasket 3, there will be a certain gap between the inner side wall of the back plate 6 and the vibration ring 7. At this time, only one vent hole 61 can be set in the middle position of the back plate 6 to enhance the strength of the back plate 6, and the gap between the back plate 6 and the vibration ring 7 can play the ventilation role of the vent hole 61, which can reduce the damping of the diaphragm 5 during vibration, and this design is also conducive to improving the sound effect of the microphone. Specifically, the number of bosses 62 can be set according to actual conditions, so as to ensure the strength of the back plate 6 while taking into account the sound effect. Preferably, the bosses 62 and the inner edge notches 72 can be staggered so that the projected areas of the bosses 62 and the inner edge notches 72 in the axial direction of the vibration component do not overlap as much as possible. At this time, the invalid capacitance area can be further reduced, and the parasitic capacitance between the back plate 6 and the diaphragm 5 can be further reduced, thereby further improving the sensitivity of the electret microphone. As shown in FIG. Figure 11 and Figure 12 As shown, the vibration assembly may further include a pole ring 10, which is provided on the surface of the back plate 6 away from the diaphragm 5. In order to further reduce the presence of parasitic capacitance, as shown in FIG. Figure 13 As shown, a plurality of protrusions 101 can be provided at intervals along the circumferential direction on the surface of the pole ring 10 away from the back plate 6, with a concave portion formed between every two adjacent protrusions 101, and the protrusions 101 are electrically connected to the circuit board 1. By providing a convex and concave structure on the pole ring 10, the parasitic capacitance can also be reduced. The improved structures of the vibration ring 7 and the vibration membrane 5, the improved structure of the back plate 6, and the improved structure of the pole ring 10 in the above-mentioned embodiments can be provided separately, or two or three of them can be included at the same time. The simultaneous provision of the three improved structures has the best improvement effect.

[0049] like Figure 11 and Figure 12As shown, this embodiment also provides an electret microphone, including the vibration assembly of the above embodiment. Specifically, the electret microphone also includes a dust screen 4, a housing 2, and a circuit board 1. The dust screen 4 and the circuit board 1 are respectively arranged at opposite ends of the housing 2. The vibration assembly is arranged in the housing 2 and is electrically connected to the circuit board 1. The circuit board 1 can be, for example, a PCB (printed circuit board). A field effect transistor and a filter capacitor are also provided on the inner surface of the circuit board 1. A sound hole is provided at the bottom of the housing 2, and a sound hole can also be opened on the circuit board 1 to change the directivity of the electret microphone.

[0050] Specifically, if Figure 14 As shown, in some embodiments, the electret microphone further includes a cavity ring 8 (in this case, the electret microphone does not include a pole ring 10) and a pole ring cavity 9. The pole ring cavity 9 is disposed on the surface of the back plate 6 on the side close to the circuit board 1. The pole ring cavity 9 is made of a metal material and may have a through hole at its center. A damping mesh 91 is disposed at the through hole. The damping mesh 91 is fixed to the inner wall of the pole ring cavity 9 at a location corresponding to the through hole and is disposed close to the back plate 6. A conductive spring 11 is disposed on the inner surface of the circuit board 1 and is electrically connected to the pole ring cavity 9. The damping mesh 91 can change the directivity of the electret microphone, turning it into a unidirectional electret microphone.

[0051] The vibration assembly and electret microphone provided in the embodiments of the present application can effectively reduce parasitic capacitance by improving the structure of internal components, thereby increasing the sensitivity and signal-to-noise ratio of the microphone, improving the sound quality, and reducing the overall weight of the microphone.

[0052] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0053] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A vibration assembly for an electret microphone, characterized in that: It includes a vibration ring, a vibration membrane, a gasket and a back plate which are stacked in sequence; the vibration membrane includes an elastic film and a conductive layer provided on the elastic film; The vibration ring includes a conductive part, which includes inner edge notches arranged at intervals along the inner edge of the vibration ring. The vibration membrane corresponding to the inner edge notches forms an insulating area, and the vibration membrane in the insulating area is insulated from the vibration membrane in the non-insulating area.

2. The vibration assembly according to claim 1, wherein The entire vibration ring is made of a conductive metal; or the vibration ring includes a base material portion and the conductive portion, and the conductive portion is at least partially located on a surface of the base material portion close to the vibration membrane; The inner edge notch is formed by the inner side wall of the vibration ring being recessed toward the outer side wall.

3. The vibration assembly according to claim 1, wherein A convex portion is formed between every two adjacent inner edge notches; The vibration ring includes a base material portion and the conductive portion, wherein the conductive portion is at least partially located on the surface of the base material portion close to the vibration membrane, and the inner edge notch is formed by the inner edge side wall corresponding to the protruding portion being recessed toward the outer edge side wall of the base material portion.

4. The vibration assembly according to claim 1, wherein The cross-sectional area of ​​the inner edge notch is 0.1-4 times the surface area of ​​the conductive portion close to the diaphragm.

5. The vibration assembly according to claim 1, wherein A plurality of bosses are provided at intervals on the outer periphery of the back plate, and the bosses are fixedly connected to the gasket.

6. The vibration assembly according to claim 5, wherein The bosses and the inner edge notches are arranged alternately.

7. The vibration assembly according to claim 5, wherein The circumferential dimension of the outer peripheral wall of the back plate between two adjacent bosses is not greater than the circumferential dimension of the inner hole of the gasket.

8. The vibration assembly according to claim 7, wherein The circumferential dimension of the outer side wall of the back plate between two adjacent bosses is smaller than the circumferential dimension of the inner hole of the gasket, and the back plate is provided with a vent hole only in the middle position.

9. The vibration assembly according to claim 1 or 5, characterized in that: It also includes a pole ring, and a surface of the pole ring away from the back plate is provided with a plurality of protrusions spaced along the circumferential direction.

10. An electret microphone, characterized in that: Comprising the vibration assembly according to any one of claims 1 to 9.

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