MEMS microphone and electronic equipment

Abstract

The utility model discloses an MEMS microphone and electronic equipment, relates to microphone technical field, MEMS microphone includes bottom plate, shell, separator plate, ASIC chip and MEMS chip, bottom plate forms flow path, shell is installed on bottom plate, shell forms the accommodation cavity, separator plate divides the accommodation cavity into first cavity and second cavity, flow path is communicated with first cavity and second cavity, the first cavity is communicated with the second cavity, the second cavity is communicated with the first cavity, the second cavity is communicated with the second cavity. The ASIC chip and the MEMS chip are both in signal connection with the bottom plate; according to the MEMS microphone, the first cavity and the second cavity are communicated through the flow channel, the first cavity and the second cavity are communicated, the cavity formed after the first cavity and the second cavity are communicated is equivalent to a back cavity of the MEMS microphone, the size of the back cavity of the MEMS microphone is not changed, and therefore the situation that the stability of the MEMS microphone is reduced due to the change of the size of the back cavity is avoided; therefore, the stability of the MEMS microphone is ensured. The MEMS chip and the ASIC chip are independently arranged in the two cavities, so that electromagnetic interference generated between the MEMS chip and the ASIC chip is reduced, and the stability of the microphone can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of microphones, and in particular to a MEMS microphone and electronic equipment. Background Art

[0002] A microphone is a device that converts sound signals into electrical signals. Microphones play an important role in various application scenarios, from daily mobile phones and headphones to professional audio equipment, broadcasting and recording equipment.

[0003] Currently available microphones usually place a MEMS chip and an ASIC chip in the cavity of the shell. During normal use, the MEMS chip and the ASIC chip will generate electromagnetic interference and radiation between them, which will lead to poor electromagnetic compatibility and anti-interference capabilities of the microphone, resulting in unstable microphone performance.

[0004] In view of this, it is necessary to provide a new MEMS microphone and electronic device to solve or at least alleviate the above technical defects. Utility Model Content

[0005] The main purpose of the utility model is to provide a MEMS microphone and an electronic device, aiming to solve the technical problem of unstable performance of MEMS microphones in the prior art.

[0006] To achieve the above objectives, according to one aspect of the utility model, the utility model provides a MEMS microphone, comprising:

[0007] a bottom plate, wherein the bottom plate is formed with a flow path;

[0008] a housing, the housing being mounted on the bottom plate and forming a receiving cavity;

[0009] a partition, the partition dividing the accommodating chamber into a first cavity and a second cavity, the flow path communicating the first cavity with the second cavity;

[0010] The ASIC chip and the MEMS chip are both connected to the baseboard signal.

[0011] In one embodiment, the shell includes a top plate and a middle layer, the middle layer is installed on the bottom plate, an open groove is formed on the side of the middle layer facing away from the bottom plate, the partition is installed at the bottom of the open groove, the side of the partition facing away from the bottom plate is connected to the side of the top plate facing the middle layer, and the top plate covers the open groove to form the accommodating cavity.

[0012] In one embodiment, a first connecting pad is formed on the side of the partition facing the top plate, and a second connecting pad is formed on the side of the intermediate layer facing the bottom plate. The first connecting pad is welded to the top plate, and the second connecting pad is welded to the bottom plate.

[0013] In one embodiment, the flow path recess is formed in the bottom plate.

[0014] In one embodiment, a first through hole is formed on the bottom surface of the first cavity, and a second through hole is formed on the bottom surface of the second cavity. The first through hole connects the first cavity and the flow path, and the second through hole connects the second cavity and the flow path.

[0015] In one embodiment, the flow path includes a connecting channel and two blind holes respectively connected to the two ends of the connecting channel, the two blind holes are respectively connected to the first through hole and the second through hole, and the aperture of the blind hole is smaller than the aperture of the first through hole and the aperture of the second through hole.

[0016] In one embodiment, a metal layer is provided on the cavity wall of the first cavity and the cavity wall of the second cavity.

[0017] In one embodiment, the metal layer is a copper-plated layer.

[0018] In one embodiment, a sound hole communicating with the accommodating cavity is provided on the top plate at a position corresponding to the MEMS chip.

[0019] According to another aspect of the utility model, the utility model further provides an electronic device, which includes the above-mentioned MEMS microphone.

[0020] In the above scheme, the MEMS microphone includes a base plate, a shell, a partition, an ASIC chip and a MEMS chip. The base plate is formed with a flow path, the shell is installed on the base plate, the shell forms a accommodating cavity, the partition divides the accommodating cavity into a first cavity and a second cavity, the flow path connects the first cavity and the second cavity, and the ASIC chip and the MEMS chip are both connected to the base plate signal; specifically, the accommodating cavity is formed in the shell, and the partition is formed in the shell, the partition divides the accommodating cavity into a first cavity and a second cavity, the ASIC chip and the MEMS chip are respectively arranged in the first cavity and the second cavity, if the ASIC chip is arranged in the first cavity, the MEMS chip is arranged in the second cavity; if the ASIC chip is arranged in the second cavity, the MEMS chip is arranged in the first cavity, then the shell is installed on the base plate, and the flow path is formed on the base plate, the first cavity and the second cavity are connected through the flow path, and the first cavity and The second cavity is connected, and the cavity after the first cavity and the second cavity are connected is equivalent to the back cavity of the MEMS microphone. Compared with the MEMS chip and ASIC chip in the prior art that are arranged in the cavity of the shell, the size of the back cavity in the utility model is consistent with the back cavity size of the MEMS microphone in the prior art, that is, the size of the back cavity is not changed, so that the stability of the MEMS microphone caused by the change of the back cavity size will not be reduced, thereby ensuring the stability of the MEMS microphone; by setting the first cavity and the second cavity, the MEMS chip and the ASIC chip are independent of each other in the two cavities, and separating the MEMS chip and the ASIC chip can achieve physical isolation, reduce the electromagnetic interference generated between the MEMS chip and the ASIC chip, and reduce the generation of radiation, thereby improving the electromagnetic compatibility and interference resistance of the MEMS microphone, thereby improving the stability of the MEMS microphone. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 An exploded view of a MEMS microphone according to an embodiment of the present invention from one perspective;

[0023] Figure 2 An exploded view of the MEMS microphone according to an embodiment of the present invention from another perspective;

[0024] Figure 3 This is a schematic diagram of the internal structure of a MEMS microphone according to an embodiment of the present invention.

[0025] Description of labels:

[0026] 100, MEMS microphone; 1, bottom plate; 11, flow path; 111, connecting channel; 112, blind hole; 2, housing; 21, accommodating cavity; 211, first cavity; 211a, first through hole; 212, second cavity; 212a, second through hole; 3, partition; 31, second connecting pad; 4, ASIC chip; 5, MEMS chip; 22, top plate; 221, sound hole; 23, middle layer; 231, opening groove; 232, first connecting pad.

[0027] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] It should be noted that all directional indications (such as up, down, etc.) in the implementation mode of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, in this utility model, the terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0031] Moreover, the technical solutions between the various embodiments of the present invention can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] A MEMS microphone 100 is a device that converts sound signals into electrical signals. The MEMS microphone 100 plays an important role in various application scenarios, from daily mobile phones and headphones to professional audio equipment, broadcasting and recording equipment.

[0033] Currently, the existing MEMS microphones 100 generally adopt a three-layer board structure. In the related art, the MEMS chip and the ASIC chip are both arranged in the cavity of the middle layer 7. In this way, when the user uses the MEMS microphone 100, the audio signal is often distorted, and the noise will mask or weaken the real sound signal received by the MEMS microphone 100. Continuous or intermittent electromagnetic interference may cause the performance of the MEMS microphone 100 to be unstable, making sound capture unreliable. In order to solve this problem, the applicant separates the MEMS chip and the ASIC chip in the cavity by shielding material, so that the mutual electromagnetic interference between the MEMS chip and the ASIC chip can be reduced. However, when the MEMS microphone 100 with such a structure is used, the applicant still finds that there will be MEMS microphone 100. Regarding the unstable performance, after multiple experiments and studies, it was found that although the MEMS chip and the ASIC chip were isolated and the mutual electromagnetic interference between them was reduced, the shielding material separated the cavity, thereby reducing the size of the back cavity of the MEMS microphone 100. Originally, the entire cavity was the back cavity of the microphone. When setting up the MEMS microphone 100, the size of the back cavity was precisely designed. Therefore, any change in its size and shape would affect the use of the MEMS microphone 100. Now, the area where the MEMS chip is located after the shielding material is separated is the back cavity. In this way, the size of the back cavity is reduced, thereby affecting the stability of the microphone. Through research, the applicant has designed a microphone structure that can avoid mutual electromagnetic interference between the MEMS chip and the ASIC chip without changing the size of the back cavity.

[0034] See also Figures 1 to 3The present invention provides a MEMS microphone 100, comprising a base plate 1, a housing 2, a partition 3, an ASIC chip, and a MEMS chip. The base plate 1 is formed with a flow path 11, the housing 2 is mounted on the base plate 1, the housing 2 forms a receiving cavity 21, the partition 3 divides the receiving cavity 21 into a first cavity 211 and a second cavity 212, the flow path 11 connects the first cavity 211 and the second cavity 212, and the ASIC chip and the MEMS chip are both signal-connected to the base plate 1; specifically, the receiving cavity 21 is formed in the housing 2, and the housing 2 is provided with a plurality of channels. The partition 3 is processed in the middle, and the partition 3 separates the accommodating cavity 21 into a first cavity 211 and a second cavity 212. The ASIC chip and the MEMS chip are respectively arranged in the first cavity 211 and the second cavity 212. If the ASIC chip is arranged in the first cavity 211, the MEMS chip is arranged in the second cavity 212; if the ASIC chip is arranged in the second cavity 212, the MEMS chip is arranged in the first cavity 211. Then, the housing 2 is mounted on the bottom plate 1, and a flow channel is formed on the bottom plate 1. Through the flow The first cavity 211 and the second cavity 212 are connected by a channel, and the first cavity 211 and the second cavity 212 are connected. The cavity formed by the connection between the first cavity 211 and the second cavity 212 is equivalent to the back cavity of the MEMS microphone 100. Compared with the prior art in which the MEMS chip and the ASIC chip are arranged in the cavity of the housing 2, the size of the back cavity in this embodiment is consistent with the size of the back cavity of the MEMS microphone 100 in the related art, that is, the size of the back cavity is unchanged. In this way, the stability of the MEMS microphone 100 is not reduced due to the change in the back cavity size, thereby ensuring the stability of the MEMS microphone 100. By providing the first cavity 211 and the second cavity 212, the MEMS chip and the ASIC chip are separated into two cavities. Separating the MEMS chip and the ASIC chip can achieve physical isolation, reduce electromagnetic interference generated between the MEMS chip and the ASIC chip, and reduce the generation of radiation. In this way, the electromagnetic compatibility and anti-interference capability of the MEMS microphone 100 can be improved, thereby improving the stability of the microphone.

[0035] See also Figures 1 to 3In one embodiment, the shell 2 includes a top plate 6 and an intermediate layer 7, the intermediate layer 7 is installed on the bottom plate 1, and an open groove 71 is formed on the side of the intermediate layer 7 facing away from the bottom plate 1. The partition 3 is installed at the bottom of the open groove 71, and the side of the partition 3 facing away from the bottom plate 1 is connected to the side of the top plate 6 facing the intermediate layer 7. The top plate 6 covers the open groove 71 to form a accommodating cavity 21. An open groove 71 is first formed on one side of the intermediate layer 7, and then the other side of the intermediate layer 7 is mounted on the bottom plate 1. The partition 3 can be installed separately in the open groove 71, or directly formed when the open groove 71 is processed. Then the top plate 6 is used to cover the side of the intermediate plate facing away from the mounting plate, so that the open groove 71 can be covered. The top plate 6 and the intermediate layer 7 cooperate with each other to form the accommodating cavity 21. In this way, the partition 3 is connected to the top plate 6 to separate the accommodating cavity 21 into a first cavity 211 and a second cavity 212. The MEMS microphone 100 is formed by sequentially connecting the top plate 6, the intermediate layer 7 and the bottom plate 1. The partition 3 is set in the middle of the accommodating cavity 21, and the two sides of the partition 3 are respectively connected to the bottom of the open groove 71 and the top plate 6. This is equivalent to strengthening the structure of the accommodating cavity 21, thereby reducing the influence of pressure on the sensitivity of the MEMS microphone 100.

[0036] See also Figures 1 to 3 In one embodiment, a first connecting pad 72 is formed on the side of the partition 3 facing the top plate 6, and a second connecting pad 31 is formed on the side of the intermediate layer 7 facing the bottom plate 1. The first connecting pad 72 is welded to the top plate 6, and the second connecting pad 31 is welded to the bottom plate 1. The top plate 6, the middle layer 7 and the bottom plate 1 are all PCB boards, so the solder paste is accurately applied to the specified position of the middle layer 7, that is, the side of the middle layer 7 facing the bottom plate 1 and the side of the partition 3 facing the top plate 6 are applied with solder paste. Here, it is necessary to ensure that the amount of solder paste is moderate and evenly distributed; use a placement machine or other methods to place the top plate 6 and the bottom plate 1 to the position coated with solder paste, that is, the top plate 6 is placed on the solder paste on the partition 3, and the bottom plate 1 is placed on the solder paste on the middle layer 7. It can also be placed manually; check whether each component is placed correctly and whether the solder paste is evenly applied; send it into the reflow oven and undergo a preheating stage to avoid thermal stress damage caused by sudden temperature changes; then enter the peak temperature zone, during which the solder paste melts and wets the component pins and PCB pads; finally, the solder joints are solidified and formed through the cooling zone; then use an optical detector or other methods to inspect the soldered PCB to ensure that there are no defects such as leaks and bridging. By providing the first connecting pad 72 on the partition 3, there is no need to provide a connecting pad on the side where the intermediate layer 7 is connected to the top plate 6. Larger bubbles are likely to remain in the connecting pad. Therefore, in this embodiment, the size of the first connecting pad 72 is much smaller than the connecting pad, which makes it easier for bubbles to overflow from the first connecting pad 72 during the reflow soldering process. This avoids the existence of large bubbles after reflow and prevents air leakage in the MEMS microphone 100.

[0037] See also Figure 2 and Figure 3 In one embodiment, the flow path 11 is recessed in the base plate 1. By forming the flow path 11 by recessing the base plate 1, compared to a traditional solid design, the recessed flow path can make the structure lighter and thinner, while reducing material usage, thereby reducing production costs and the weight of the MEMS microphone 100. Furthermore, such a flow path is easier to process, and can be processed through methods such as laser processing and etching. This allows for the processing of flow paths with more complex shapes, reducing manufacturing difficulty.

[0038] See also Figure 1 and Figure 3 In one embodiment, a first through-hole 211a is formed on the bottom surface of the first cavity 211, and a second through-hole 212a is formed on the bottom surface of the second cavity 212. The first through-hole 211a connects the first cavity 211 with the flow path 11, and the second through-hole 212a connects the second cavity 212 with the flow path 11. Because the electromagnetic interference emitted by the ASIC chip and the MEMS chip radiates in all directions, the first through-hole 211a and the second through-hole 212a, which are connected to the flow path 11, are provided on the bottom surfaces of the first cavity 211 and the second cavity 212, respectively. This prevents the electromagnetic interference emitted by the ASIC chip and the MEMS chip from entering the MEMS chip cavity and the ASIC chip cavity, respectively, and affecting the operation of the MEMS chip and the ASIC chip. This structural arrangement further effectively prevents mutual interference between the MEMS chip and the ASIC chip, which could affect the operational stability of the MEMS microphone 100.

[0039] See also Figure 2 and Figure 3 In one embodiment, the flow path 11 includes a connecting channel 111 and two blind holes 112 respectively connected to the two ends of the connecting channel 111, and the two blind holes 112 are respectively connected to the first through hole 211a and the second through hole 212a, and the aperture of the blind hole 112 is smaller than the aperture of the first through hole 211a and the aperture of the second through hole 212a. Two blind holes 112 are provided to communicate with the first through hole 211a and the second through hole 212a respectively, and then the two blind holes 112 are connected to each other through the connecting channel 111, so that the first cavity 211 and the second cavity 212 can be connected. Since there are many components and circuits on the bottom plate 1, in order to achieve the function of connecting the first cavity 211 and the second cavity 212, while avoiding the components and circuits on the bottom plate 1, the apertures of the two blind holes 112 are set to be smaller than the apertures of the first through hole 211a and the apertures of the second through hole 212a. In this way, the first cavity 211 and the second cavity 212 can be connected, and the components and circuits on the bottom plate 1 can be avoided as much as possible.

[0040] In one embodiment, a metal layer is provided on the walls of the first cavity 211 and the second cavity 212. The metal layer is applied to the walls of the first cavity 211 and the second cavity 212. Here, the metal layer refers to the side walls of the first cavity 211 and the side walls of the second cavity 212, excluding the bottom surfaces of the first cavity 211 and the second cavity 212. In this way, the metal layer can shield the MEMS chip and the ASIC chip, respectively, thereby enhancing the electromagnetic interference resistance of the MEMS microphone 100.

[0041] In one embodiment, the metal layer is a copper-plated layer. Copper-plated layers have excellent electrical conductivity, which means they can effectively reflect and absorb electromagnetic waves, thereby providing a highly effective electromagnetic shielding effect. Compared to precious metals such as gold and silver, copper is more affordable, resulting in a lower cost. Copper-plated layers are also relatively soft and easy to process into various shapes and thicknesses. Compared to other shielding materials, copper-plated layers have a lower density, which can reduce the weight of the MEMS microphone 100.

[0042] See also Figures 1 to 3 In one embodiment, a sound hole 61 is provided on the top plate 6 at a position corresponding to the MEMS chip, communicating with the accommodating cavity 21. The sound hole 61 allows sound waves from the external environment to enter the MEMS chip. The sound waves are then transmitted to the vibrating membrane of the MEMS chip through the sound hole 61 and converted into electrical signals. Here, the sound hole 61 is positioned directly opposite the MEMS chip, so that the sound waves can directly enter the vibrating membrane of the MEMS chip through the sound hole 61, further improving the processing efficiency of the MEMS microphone 100. The sound hole 61 can help maintain the air pressure balance between the inside of the MEMS microphone 100 and the external environment. If the microphone is completely enclosed, changes in temperature or ambient pressure may cause internal pressure imbalance, which may affect the normal operation of the MEMS microphone 100. By adjusting the position, size, and shape of the sound hole 61, the sound capture characteristics of the MEMS microphone 100, including sensitivity and frequency response curve, can be affected.

[0043] According to another aspect of the present invention, an electronic device is provided, comprising the aforementioned MEMS microphone 100. Since the electronic device comprises all technical solutions of the aforementioned MEMS microphone 100, it has at least all the beneficial effects brought about by all the technical solutions, which will not be described in detail here.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and do not limit the patent scope of the present utility model; although the present application has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that under the technical concept of the present utility model, it is still possible to modify the technical solutions recorded in the above embodiments, or to replace some or all of the technical features therein; or directly / indirectly apply them to other related technical fields, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A MEMS microphone, characterized in that: include: a bottom plate, wherein the bottom plate is formed with a flow path; a housing, the housing being mounted on the bottom plate and forming a receiving cavity; a partition, the partition dividing the accommodating chamber into a first cavity and a second cavity, the flow path communicating the first cavity with the second cavity; The ASIC chip and the MEMS chip are both connected to the baseboard signal.

2. The MEMS microphone according to claim 1, wherein: The shell includes a top plate and a middle layer, the middle layer is installed on the bottom plate, an open groove is formed on the side of the middle layer facing away from the bottom plate, the partition is installed at the bottom of the open groove, the side of the partition facing away from the bottom plate is connected to the side of the top plate facing the middle layer, and the top plate covers the open groove to form the accommodating cavity.

3. The MEMS microphone according to claim 2, wherein: A first connection pad is formed on the side of the partition facing the top plate, and a second connection pad is formed on the side of the intermediate layer facing the bottom plate. The first connection pad is welded to the top plate, and the second connection pad is welded to the bottom plate.

4. The MEMS microphone according to any one of claims 1 to 3, characterized in that The flow path recess is formed in the bottom plate.

5. The MEMS microphone according to any one of claims 1 to 3, characterized in that A first through hole is formed on the bottom surface of the first cavity, and a second through hole is formed on the bottom surface of the second cavity. The first through hole connects the first cavity and the flow path, and the second through hole connects the second cavity and the flow path.

6. The MEMS microphone according to claim 5, characterized in that The flow path includes a connecting channel and two blind holes respectively connected to both ends of the connecting channel, the two blind holes are respectively connected to the first through hole and the second through hole, and the aperture of the blind holes is smaller than the aperture of the first through hole and the aperture of the second through hole.

7. The MEMS microphone according to any one of claims 1 to 3, characterized in that The cavity wall of the first cavity and the cavity wall of the second cavity are both provided with a metal layer.

8. The MEMS microphone according to claim 7, wherein: The metal layer is a copper-plated layer.

9. The MEMS microphone according to any one of claims 2 or 3, characterized in that A sound hole communicating with the accommodating cavity is provided on the top plate at a position corresponding to the MEMS chip.

10. An electronic device, characterized in that: The electronic device comprises the MEMS microphone according to any one of claims 1 to 9.

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