Circuit board, MEMS microphone and electronic equipment

Abstract

The invention discloses a circuit board, an MEMS microphone and electronic equipment, and relates to the technical field of semiconductors, the circuit board comprises a substrate, a conductive layer and a ground ring, the conductive layer is arranged on one surface of the substrate and is provided with a mounting hole, and the mounting hole penetrates through two opposite surfaces of the conductive layer and exposes part of the surface of the substrate; the ground ring is arranged on one side, opposite to the substrate, of the conductive layer corresponding to the mounting hole and is connected to the conductive layer, and an elastic material is arranged between the ground ring and the substrate; according to the technical scheme provided by the invention, the falling impact resistance of the MEMS microphone can be improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a circuit board, a MEMS microphone and an electronic device. Background Art

[0002] At present, the chip of MEMS microphone is usually mounted on the circuit board and then packaged inside using tooling. However, the circuit board is usually an assembled printed circuit board, and its material is relatively hard. When the MEMS microphone falls, the external instantaneous impact force will be directly transmitted to the MEMS microphone chip through the circuit board, causing damage to the diaphragm of the MEMS microphone chip. In other words, the MEMS microphone has poor anti-drop impact performance. Summary of the invention

[0003] The main purpose of the present invention is to provide a circuit board, a MEMS microphone and an electronic device, aiming to improve the drop impact resistance performance of the MEMS microphone.

[0004] To achieve the above object, the present invention provides a circuit board, which is applied to a MEMS microphone. The circuit board includes:

[0005] substrate;

[0006] A conductive layer, the conductive layer is disposed on a surface of the substrate and is provided with a mounting hole, the mounting hole penetrates two opposite surfaces of the conductive layer and exposes a portion of the surface of the substrate;

[0007] A ground ring is arranged on a side of the conductive layer facing away from the substrate corresponding to the mounting hole and connected to the conductive layer, and an elastic material is arranged between the ground ring and the substrate.

[0008] In one embodiment, the resilient material is at least partially located on the inner side of the ground ring.

[0009] In one embodiment, the ground ring comprises:

[0010] A ring body, the ring body being arranged on a side of the conductive layer facing away from the substrate corresponding to the mounting hole; and a cantilever, one end of the cantilever being connected to the ring body and the other end being connected to the conductive layer;

[0011] The elastic material is disposed between the ring body and the base plate, and is at least partially located on the inner side of the ring body.

[0012] In one embodiment, the cantilever extends in a radial direction of the ring body; or, the cantilever is an arc-shaped cantilever.

[0013] In one embodiment, the cantilever is provided in plurality, and the plurality of cantilevers are spaced apart along the circumference of the ring body; and / or the distance between the ring body and the substrate is 0.05 mm-0.2 mm.

[0014] In one embodiment, the substrate is provided with a through hole penetrating two opposite surfaces corresponding to the mounting hole, the through hole is located inside the mounting hole, and the elastic material is arranged on the periphery of the through hole.

[0015] In one embodiment, the circuit board further comprises a solder resist layer, the solder resist layer covers a portion of the surface of the conductive layer, and a solder pad is formed on a portion of the conductive layer not covered by the solder resist layer;

[0016] The insulating portion of the substrate connected to the pad forms a cavity corresponding to the pad, so that the pad is suspended in the air.

[0017] In one embodiment, in a direction parallel to the surface of the substrate, the size of the cavity is greater than 1.1 times the size of the pad; and / or the pads are spaced apart in a plurality, and the insulating portion of the substrate corresponding to the plurality of pads forms a plurality of the cavities so that the plurality of pads are all suspended; and / or the cavity is filled with elastic material.

[0018] The present invention further provides a MEMS microphone, comprising: the circuit board as described above; and a MEMS chip, wherein the MEMS chip is arranged on the circuit board.

[0019] The present invention further provides an electronic device, comprising the MEMS microphone as described above.

[0020] The circuit board provided by the present invention includes a substrate, a conductive layer and a ground ring. The conductive layer is arranged on a surface of the substrate and is provided with mounting holes. The mounting holes penetrate the two opposite surfaces of the conductive layer and expose part of the surface of the substrate. The mounting holes of the ground ring are arranged on the side of the conductive layer facing away from the substrate, and are connected to the conductive layer. An elastic material is arranged between the ground ring and the substrate. The circuit board of the present invention is applied to a MEMS microphone. When the MEMS microphone falls, the external instantaneous impact force will be transmitted to the circuit board first. When the impact force reaches the position of the ground ring, since the elastic material is arranged between the ground ring and the substrate in the circuit board, the elastic material will absorb part of the impact force and shrink, and the impact energy transmitted to the MEMS microphone chip will be greatly reduced, thereby protecting the diaphragm of the MEMS microphone chip from damage. That is, the MEMS microphone has good anti-fall impact performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 Schematic structural diagram of an embodiment of the circuit board provided by the present invention;

[0023] Figure 2 Schematic structural diagram of another embodiment of the circuit board provided by the present invention;

[0024] Figure 3 Schematic partial cross-sectional structure diagram of the circuit board provided by the present invention at the ground loop;

[0025] Figure 4 Schematic partial cross-sectional structure diagram of the circuit board provided by the present invention at the solder pad.

[0026] Explanation of the reference numerals in the drawings:

[0027] 100, circuit board; 10, substrate; 11, through hole; 12, cavity; 20, conductive layer; 21, mounting hole; 22, solder pad; 30, ground loop; 31, loop body; 32, cantilever; 40, elastic material; 41, relief through hole; 50, solder mask layer.

[0028] The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0031] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] At present, the circuit board of a MEMS microphone is usually an assembled printed circuit board (PCBA), which usually includes a substrate, a conductive layer arranged on one surface of the substrate, and a solder mask layer covering at least part of the surface of the conductive layer, wherein the uncovered part of the conductive layer is formed with a ground ring and a solder pad, and the ground ring is arranged on the surface of the substrate, and the whole is a multi-layer structure, and its material is relatively hard. When a MEMS microphone falls, the external instantaneous impact force will be directly transmitted to the chip of the MEMS microphone through the circuit board, causing the diaphragm of the MEMS microphone chip to be damaged, that is, the MEMS microphone has poor anti-drop impact performance.

[0033] In view of the above technical problems, the present invention proposes a circuit board for a MEMS microphone, aiming to improve the drop impact resistance performance of the MEMS microphone.

[0034] See also Figures 1 to 3 In one embodiment of the present invention, a circuit board 100 includes a substrate 10, a conductive layer 20 and a ground ring 30. The conductive layer 20 is arranged on a surface of the substrate 10 and is provided with a mounting hole 21. The mounting hole 21 penetrates two opposite surfaces of the conductive layer 20 and exposes a portion of the surface of the substrate 10. The ground ring 30 is arranged on a side of the conductive layer 20 facing away from the substrate 10 corresponding to the mounting hole 21 and is connected to the conductive layer 20. An elastic material 40 is arranged between the ground ring 30 and the substrate 10.

[0035] Specifically, the substrate 10 is a multi-layer structure, including multiple insulating layers and multiple metal layers alternately stacked, wherein the insulating layer serves to isolate the metal layer to prevent short circuits between different metal layers, and the insulating layer can be an insulating layer formed after the semi-cured sheet is cured. The specific production is conventional operation, which will not be described one by one here. The conductive layer 20 can be a copper foil layer, which has good electrical conductivity, thermal conductivity and mechanical properties, and is used to transmit electrical signals and currents. The conductive layer 20 is provided with a mounting hole 21 that passes through two opposite surfaces, which is used to place the ground ring 30. Since the shape of the ground ring 30 is usually circular, the mounting hole 21 can be a circular hole. Of course, the mounting hole 21 can also be an elliptical, square or other reasonable shape, which is not limited here. The ground ring 30 is used for electrical grounding to reduce electromagnetic interference. The material of the ground ring 30 is a conductive material, which can be copper foil, which has good electrical conductivity and thermal conductivity. The ground ring 30 is arranged on the side of the conductive layer 20 facing away from the substrate 10 corresponding to the mounting hole 21, that is, the ground ring 30 and the conductive layer 20 are not in the same plane, the ground ring 30 protrudes from the mounting hole 21, and there is a gap between the ground ring 30 and the substrate 10. In addition, the ground ring 30 is connected to the side wall of the mounting hole 21, that is, the ground ring 30 is connected to the conductive layer 20. An elastic material 40 is arranged between the ground ring 30 and the substrate 10. When the impact force is transmitted to the ground ring 30, the elastic material 40 will absorb part of the impact energy and shrink, thereby greatly reducing the impact force transmitted to the MEMS microphone chip, thereby protecting the diaphragm of the MEMS microphone chip from damage. Of course, after the external impact force disappears, the elastic material 40 will return to its original state due to its own elasticity, so that the ground ring 30 returns to its original shape, thereby the elasticity of the elastic material 40 can be reused to effectively resist the external impact force.

[0036] It should be noted that the elastic material 40 can be arranged in part of the gap between the ground ring 30 and the substrate 10, or can be arranged in all the gaps between the ground ring 30 and the substrate 10. In this case, the elastic material 40 is at least partially located on the inner side of the ground ring 30. The specific arrangement of the elastic material 40 is not limited here and is within the protection scope of the present invention.

[0037] The circuit board 100 of the present invention is applied to a MEMS microphone. When the MEMS microphone falls, the external instantaneous impact force is first transmitted to the circuit board 100. When the impact force reaches the position of the ground ring 30, since the elastic material 40 is arranged between the ground ring 30 and the substrate 10 in the circuit board 100, the elastic material 40 absorbs part of the impact force and shrinks, and the impact energy transmitted to the MEMS microphone chip is greatly reduced, thereby protecting the diaphragm of the MEMS microphone chip from damage. That is, the MEMS microphone has good anti-drop impact performance.

[0038] Optionally, the elastic material 40 includes but is not limited to at least one of silicone, polyurethane foam, rubber, and thermoplastic elastomer.

[0039] Optionally, the ground ring 30 and the conductive layer 20 are an integrated structure, thereby increasing structural stability and reliability, achieving a better grounding effect, and reducing electromagnetic interference.

[0040] Refer again Figures 1 to 3 In one embodiment of the present invention, the elastic material 40 is at least partially located on the inner side of the ground ring 30, that is, a part of the elastic material 40 is in contact with the ground ring 30, and another part is located on the inner side of the ground ring 30 and is not in contact with the ground ring 30. The surface of this part is exposed. When the external impact force is transmitted to the circuit board 100 and reaches the ground ring 30, a part of the impact energy is absorbed by the elastic material 40 in contact with the ground ring 30 through the ground ring 30, and another part of the impact energy is directly absorbed by the elastic material 40 located on the inner side of the ground ring 30. This can more effectively reduce the impact energy transmitted to the MEMS microphone chip and more effectively protect the MEMS microphone chip. That is, the MEMS microphone has better anti-drop impact performance.

[0041] Refer again Figures 1 to 3 In one embodiment of the present invention, the ground ring 30 includes a ring body 31 and a cantilever 32. The ring body 31 is arranged on the side of the conductive layer 20 facing away from the substrate 10 corresponding to the mounting hole 21. The elastic material 40 is arranged between the ring body 31 and the substrate 10, and at least partially located on the inner side of the ring body 31. One end of the cantilever 32 is connected to the ring body 31, and the other end is connected to the conductive layer 20.

[0042] Specifically, the ring body 31 is roughly in the form of a circular ring structure, and its specific size is determined according to the actual needs of the product to ensure a good electrical grounding effect. The radial size of the ring body 31 is smaller than the radial size of the mounting hole 21. The ring body 31 is arranged on the side of the conductive layer 20 facing away from the substrate 10 corresponding to the mounting hole 21, that is, the ring body 31 and the conductive layer 20 are not in the same plane, and there is a certain distance between the ring body 31 and the substrate 10. Since the ring body 31 and the conductive layer 20 are not in the same plane, the cantilever 32 is arranged to be inclined and suspended, that is, there is also a distance between the cantilever 32 and the substrate 10. The cantilever 32 has two opposite ends, one end of which is connected to the ring body 31, and the other end is connected to the inner wall of the mounting hole 21 (that is, the conductive layer 20). The cantilever 32 can be selected as a straight line, an arc line, or other reasonable curves, and its specific shape is not limited.

[0043] The structure of the ground ring 30 in the embodiment of the present invention is relatively simple, and the setting stability and reliability are good, so the electrical grounding effect of the ground ring 30 is better.

[0044] Optionally, the ring body 31, the cantilever 32 and the conductive layer 20 are an integrated structure, thereby increasing structural stability and reliability, achieving a better grounding effect, and reducing electromagnetic interference.

[0045] It should be noted that the main function of the cantilever 32 is to provide mechanical support and electrical connection rather than direct buffering. In the embodiment of the present invention, the elastic material 40 is arranged in the area between the ring body 31 and the substrate 10 rather than in the area between the cantilever 32 and the substrate 10. This can reduce the mechanical burden of the cantilever 32 and improve its structural stability, while simplifying the manufacturing process and reducing the manufacturing cost.

[0046] Refer again Figure 1 In one embodiment of the present invention, the cantilever 32 extends radially along the ring body 31, that is, the cantilever 32 is linear, has a simple structure, is easy to design and manufacture, and can provide stable mechanical support to enhance the structural strength of the ground ring 30.

[0047] Refer again Figure 2 In one embodiment of the present invention, the cantilever 32 is an arc-shaped cantilever, that is, the cantilever 32 is curved. Compared with the straight cantilever, the length of the arc-shaped cantilever is relatively long, thereby reducing the connection stiffness between the ground ring 30 and the conductive layer 20. When the impact force is transmitted to the ground ring 30, the impact energy can be better buffered and absorbed by the elastic material 40, thereby having better anti-drop impact performance.

[0048] In some embodiments of the present invention, a plurality of cantilevers 32 are provided, and the plurality of cantilevers 32 are distributed at intervals along the circumference of the ring body 31 .

[0049] Specifically, in one embodiment of the present invention, Figure 1 As shown, the cantilever 32 is linear and is provided in multiple numbers, and the multiple cantilever 32 is evenly distributed along the circumference of the ring body 31, and each cantilever 32 extends along the radial direction of the ring body 31. With this arrangement, the connection stability of the ground ring 30 is better, which can more effectively improve its grounding effect, and can also distribute stress more evenly, avoid stress concentration, and improve the stability of the overall structure.

[0050] In another embodiment of the present invention, Figure 2 As shown, the cantilever 32 is an arc-shaped cantilever, and is arranged in multiple numbers. The multiple cantilevers 32 are evenly distributed along the circumference of the ring body 31. This arrangement can not only improve the connection stability and grounding effect of the ground ring 30 and improve the stability of the overall structure, but also reduce the connection stiffness between the ground ring 30 and the conductive layer 20, and improve the drop impact resistance of the overall structure.

[0051] Of course, in some other embodiments, the multiple cantilevers 32 can have other reasonable shapes, or the shapes of the multiple cantilevers 32 are different.

[0052] In one embodiment of the present invention, the distance between the ring body 31 and the substrate 10 (ie, the set thickness of the elastic material 40) is 0.05mm-0.2mm (eg, 0.05mm, 0.1mm, 0.15mm, 0.2mm and any interval between the two end points).

[0053] The embodiment of the present invention designs the distance between the ring body 31 and the substrate 10 to be within the above range, which can ensure that the elastic material 40 has a good buffering and absorbing effect on external impact, improve the drop impact resistance of the circuit board 100, and ensure that the ground ring 30 has good mechanical stability. If the distance between the ring body 31 and the substrate 10 is less than 0.05mm, the absorption and buffering effect of the elastic material 40 is limited, and then the drop impact resistance of the circuit board 100 is not significantly improved; if the distance between the ring body 31 and the substrate 10 is greater than 0.2mm, the mechanical stability of the ground ring 30 is relatively poor.

[0054] See again Figures 1 to 3 In one embodiment of the present invention, the substrate 10 is provided with a through hole 11 penetrating two opposite surfaces corresponding to the mounting hole 21 , the through hole 11 is located inside the mounting hole 21 , and the elastic material 40 is disposed on the periphery of the through hole 11 .

[0055] Specifically, the through hole 11 is a generally circular hole, penetrating two opposite surfaces of the substrate 10, and the through hole 11 is located inside the mounting hole 21 and communicates with the mounting hole 21. The elastic material 40 is located at the periphery of the through hole 11, and a clearance through hole 41 is formed corresponding to the through hole 11, the clearance through hole 41 is communicated with the through hole 11, and the radial dimension of the clearance through hole 41 is not less than the radial dimension of the through hole 11, that is, the elastic material 40 does not cover the through hole 11, and the through hole 11 and the clearance through hole 41 jointly form a sound hole, which penetrates two opposite surfaces of the circuit board 100, and is used to provide a sound channel for the MEMS chip.

[0056] Optionally, the clearance hole 41 is a circular through hole, and the radial dimension of the clearance hole 41 is the same as the radial dimension of the through hole 11, that is, the sound hole as a whole is a circular through hole with the same radial dimension. Therefore, the elastic material 40 is at least partially located on the inner side of the ground ring 30, and the MEMS microphone has better anti-drop impact performance.

[0057] Of course, in some other embodiments, the MEMS microphone also includes a packaging shell, which is mounted on the circuit board 100 and encloses a packaging structure. The MEMS chip is arranged in the packaging structure, and the sound hole can be arranged on the packaging shell, and its specific setting position is not limited.

[0058] See again Figure 1 , Figure 2 and Figure 4 In an embodiment of the present invention, the circuit board 100 further includes a solder resist layer 50, which covers a portion of the surface of the conductive layer 20, and a pad 22 is formed on the portion of the conductive layer 20 not covered by the solder resist layer 50; the insulating portion of the substrate 10 connected to the pad 22 forms a cavity 12 corresponding to the pad 22, so that the pad 22 is suspended in the air.

[0059] The solder resist layer 50 is used to protect the conductive layer 20 from oxidation and contamination, and to prevent short circuits during welding, thereby increasing the service life of the circuit board 100. The material of the solder resist layer 50 may be a photosensitive polymer, including but not limited to at least one of epoxy resin, polyimide, and acrylic resin. The preparation of the solder resist layer 50 is a conventional operation and will not be described in detail here. The portion of the conductive layer 20 not covered by the solder resist layer 50 is formed with a solder pad 22, which is used to connect the pins of the external electronic components and the conductive path of the circuit board 100. The shape of the solder pad 22 may be circular, square, elliptical or other reasonable shapes, which are not limited here. The specific size of the solder pad 22 may be determined according to the pin size of the external electronic component and the welding process. The substrate 10 is a multi-layer structure, including multiple insulating layers and multiple metal layers alternately stacked, wherein a layer in the substrate 10 connected to the conductive layer 20 is an insulating layer, which can be selected as an insulating layer formed by a semi-cured sheet after curing. The insulating portion of the substrate 10 corresponding to the pad 22 is hollowed out to form a cavity 12, so that the pad 22 is suspended. The shape of the cavity 12 can be arc, square or other reasonable shapes, which is not limited here, as long as the pad 22 can be suspended.

[0060] When the MEMS microphone falls, the external instantaneous impact force will be transmitted to the circuit board 100 first. When the impact force reaches the pad 22, since the pad 22 is suspended, the corresponding cavity 12 will absorb and buffer part of the impact energy, thereby reducing the impact energy transmitted to the MEMS microphone chip, more effectively protecting the diaphragm of the MEMS microphone chip from damage, and further improving the drop impact resistance of the MEMS microphone.

[0061] In order to ensure that the cavity 12 can absorb the impact energy more effectively, the size of the cavity 12 should be designed appropriately. In an optional embodiment, in the direction parallel to the surface of the substrate 10, the size of the cavity 12 is greater than 1.1 times the size of the pad 22. For example, the pad 22 is a square pad 22, the size of the cavity 12 along the length direction of the pad 22 is greater than 1.1 times the length of the pad 22, and the size of the cavity 12 along the width direction of the pad 22 is greater than 1.1 times the width of the pad 22. With this design, the cavity 12 can absorb the external impact energy more effectively, thereby more effectively reducing the impact energy transmitted to the MEMS microphone chip, and more effectively improving the drop impact resistance of the MEMS microphone.

[0062] Please refer again Figure 1 and Figure 2 In one embodiment of the present invention, the pads 22 are arranged at intervals to be multiple, and the insulating portion of the substrate 10 corresponding to the multiple pads 22 forms a plurality of cavities 12, so that the multiple pads 22 are all suspended.

[0063] In the embodiment of the present invention, the insulating portion of the substrate 10 corresponding to each pad 22 forms a cavity 12, so that each pad 22 is suspended. Therefore, each cavity 12 can absorb external impact energy, thereby reducing the impact energy transmitted to the MEMS microphone chip, more effectively protecting the diaphragm of the MEMS microphone chip from damage, and further improving the drop impact resistance of the MEMS microphone.

[0064] Furthermore, in some embodiments of the present invention, the cavity 12 is filled with an elastic material, and the elastic material includes but is not limited to at least one of silicone, polyurethane foam, rubber, and thermoplastic elastomer.

[0065] It should be noted that the elastic material filled in the cavity 12 and the elastic material 40 filled between the ground ring 30 and the substrate 10 may be the same or different, which is not limited here.

[0066] When the MEMS microphone falls, the external instantaneous impact force will be transmitted to the circuit board 100 first. When the impact force reaches the pad 22, since the pad 22 is suspended, the elastic material in the corresponding cavity 12 will absorb part of the impact energy, thereby reducing the impact energy transmitted to the MEMS microphone chip, more effectively protecting the diaphragm of the MEMS microphone chip from damage, and further improving the drop impact resistance of the MEMS microphone.

[0067] It should be noted that, compared with a simple cavity 12 design, the cavity 12 is filled with elastic material, so that the MEMS microphone has better drop impact resistance and can withstand greater external impact force.

[0068] Of course, when there are multiple pads 22, the cavity 12 corresponding to each pad 22 is filled with elastic material, so that the MEMS microphone has better drop impact resistance and can withstand greater external impact force.

[0069] Refer again Figure 4In one embodiment of the present invention, the substrate 10 includes three metal layers and three insulating layers alternately stacked, and the three metal layers can be electrically connected through vias and metal traces therein, and the specific structure is not limited here. Among them, the insulating layer is connected to the conductive layer 20, and the insulating layer forms a cavity 12 corresponding to the pad 22. The outermost layer of the side of the substrate 10 away from the conductive layer 20 is a metal layer. In order to protect the metal layer from oxidation and contamination, a solder resist layer 50 is provided on the surface of the metal layer. The specific configuration of the solder resist layer 50 can refer to the above embodiment, and will not be repeated here. Of course, in some other embodiments, the specific structure of the substrate 10 can also be other reasonable multi-layer structures.

[0070] The present invention further provides a MEMS microphone, which includes a circuit board 100 and a MEMS chip. The specific structure of the circuit board 100 refers to the above embodiment. Since the MEMS microphone adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0071] When the MEMS microphone falls, the external instantaneous impact force will be transmitted to the circuit board 100 first. Since the elastic material 40 is arranged between the ground ring 30 and the substrate 10 in the circuit board 100, the elastic material 40 will absorb part of the impact force and shrink, and the impact energy transmitted to the MEMS microphone chip will be greatly reduced, thereby protecting the diaphragm of the MEMS microphone chip from damage. That is, the MEMS microphone has good anti-drop impact performance.

[0072] In one embodiment of the present invention, the MEMS microphone further includes a packaging shell, which is mounted on the circuit board 100 and encloses a packaging structure, the MEMS chip is arranged in the packaging structure, the sound hole is opened in the packaging shell or the circuit board 100, and the MEMS chip is arranged on the circuit board 100 opposite the sound hole.

[0073] The present invention also provides an electronic device, which includes a MEMS microphone. The specific structure of the MEMS microphone refers to the above embodiment. Since the electronic device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the electronic device includes but is not limited to headphones, mobile phones, smart watches and tablet computers.

[0074] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A circuit board, applied to a MEMS microphone, characterized in that: The circuit board comprises: substrate; A conductive layer, the conductive layer is disposed on a surface of the substrate and is provided with a mounting hole, the mounting hole penetrates two opposite surfaces of the conductive layer and exposes a portion of the surface of the substrate; A ground ring is arranged on a side of the conductive layer facing away from the substrate corresponding to the mounting hole and connected to the conductive layer, and an elastic material is arranged between the ground ring and the substrate.

2. The circuit board according to claim 1, characterized in that: The resilient material is at least partially located on the inner side of the ground ring.

3. The circuit board according to claim 1, characterized in that: The ground ring comprises: a ring body, the ring body being arranged on a side of the conductive layer facing away from the substrate corresponding to the mounting hole; and A cantilever, one end of the cantilever is connected to the ring body, and the other end of the cantilever is connected to the conductive layer; The elastic material is disposed between the ring body and the base plate, and is at least partially located on the inner side of the ring body.

4. The circuit board according to claim 3, characterized in that: The cantilever extends in the radial direction of the ring body; or, The cantilever is an arc-shaped cantilever.

5. The circuit board according to claim 3, characterized in that: The cantilever is provided in plurality, and the plurality of cantilever are distributed at intervals along the circumference of the ring body; and / or, The distance between the ring body and the substrate is 0.05 mm-0.2 mm.

6. The circuit board according to claim 1, characterized in that: The substrate is provided with a through hole penetrating two opposite surfaces corresponding to the mounting hole, the through hole is located inside the mounting hole, and the elastic material is arranged on the periphery of the through hole.

7. The circuit board according to any one of claims 1 to 6, characterized in that: The circuit board further comprises a solder resist layer, wherein the solder resist layer covers a portion of the surface of the conductive layer, and a solder pad is formed on a portion of the conductive layer not covered by the solder resist layer; The insulating portion of the substrate connected to the pad forms a cavity corresponding to the pad, so that the pad is suspended in the air.

8. The circuit board according to claim 7, characterized in that: In a direction parallel to the surface of the substrate, the size of the cavity is greater than 1.1 times the size of the pad; and / or, The pads are arranged to be spaced apart in a plurality, and the insulating portion of the substrate corresponding to the plurality of pads forms a plurality of cavities, so that the plurality of pads are suspended in the air; and / or, The cavity is filled with elastic material.

9. A MEMS microphone, characterized in that: The MEMS microphone comprises: A circuit board as claimed in any one of claims 1 to 8; and A MEMS chip is arranged on the circuit board.

10. An electronic device, characterized in that: The electronic device comprises the MEMS microphone as claimed in claim 9.

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