MEMS microphone

Abstract

The utility model provides a kind of MEMS microphone, it includes the shell with accommodating space and the ASIC chip and the MEMS chip with back cavity accommodated in accommodating space, shell includes shell and the PCB board with shell cover interface and form accommodating space, PCB board is equipped with the first sound hole through PCB board and with back cavity communication, MEMS microphone further include waterproof membrane fixed between MEMS chip and PCB board and cover first sound hole;The utility model provides MEMS microphone further include support plate that is fixedly glued to PCB board and cover first sound hole, support plate is equipped with the second sound hole through support plate and with first sound hole communication, waterproof membrane is fixed to the surface of support plate towards MEMS chip and cover second sound hole, first sound hole and second sound hole are staggered and set, effectively buffer the impact of water pressure to waterproof membrane, avoid that waterproof membrane can be destroyed due to the impact of water pressure, and then improve the stability of MEMS microphone product performance.

Description

【TECHNICAL FIELD】

[0001] The utility model relates to the field of electric -acoustic conversion, especially a MEMS microphone. 【BACKGROUND TECHNIQUE】

[0002] The MEMS microphone usually comprises a shell, a circuit board forming a receiving space with the shell cover, and an ASIC chip and a MEMS chip received in the receiving space, and these structures work cooperatively to realize the collection and processing of sound signals.

[0003] In order to meet the waterproof function of electronic equipment, a waterproof film is arranged in the structure of the MEMS microphone to form a waterproof MEMS microphone. In the prior art, the waterproof film in the MEMS microphone is arranged between the PCB board and the MEMS chip and is directly fixed on the PCB board. However, when water pressure impacts the MEMS microphone, the waterproof film is easily deformed too much under the impact of water pressure, resulting in the failure of the waterproof function and further damaging the performance of the MEMS microphone product.

[0004] Therefore, it is necessary to provide a new MEMS microphone to solve the above technical problems. 【UTILITY MODEL CONTENTS】

[0005] The utility model provides a kind of MEMS microphone, it includes the shell with receiving space, receiving in the ASIC chip of the receiving space and the MEMS chip with back cavity, the shell includes shell body and with the PCB board of the shell cover and form the receiving space, the PCB board is equipped with first sound hole passing through the PCB board and with the back cavity communication, the MEMS microphone further includes fixed between the MEMS chip and the PCB board and covers the first sound hole of waterproof film;The MEMS microphone further includes that the support plate of adhesive fixed to the PCB board and covers the first sound hole, the support plate is equipped with second sound hole passing through the support plate and with the first sound hole communication, the waterproof film is fixed to the surface of the support plate towards the MEMS chip and covers the second sound hole, the first sound hole and the second sound hole are staggered arrangement each other.

[0006] Preferably, the number of the first sound hole is two or more than two, and each first sound hole is staggered with the second sound hole.

[0007] Preferably, the number of the second sound hole is two or more than two, and each second sound hole is staggered with the first sound hole.

[0008] Preferably, the PCB board comprises a groove recessed from a surface of the PCB board towards the support plate and away from the support plate, the support plate covers the groove, the first sound hole penetrates the PCB board from a groove bottom surface of the groove.

[0009] Preferably, the waterproof film comprises a fixed part fixed to the support plate and an intermediate part connected to the fixed part, a thickness of the intermediate part is less than a thickness of the fixed part, and the intermediate part is arranged in a spaced-apart manner relative to the support plate.

[0010] Preferably, the support plate is clamped between the waterproof film and the PCB board, and the waterproof film completely covers the range of the support plate in the orthographic projection towards the PCB board.

[0011] Preferably, the MEMS chip completely covers the range of the waterproof film in the orthographic projection towards the PCB board.

[0012] The utility model provides a kind of MEMS microphone including setting support plate between waterproof film and PCB board, support plate is equipped with the second sound hole that penetrates support plate and is communicated with first sound hole, the second sound hole is arranged with first sound hole on the PCB board mutually staggered, the direct impact of water pressure to waterproof film is buffered, and then the waterproof function of waterproof film is protected, and the stability of MEMS microphone product performance is improved. 【DESCRIPTION OF DRAWINGS】

[0013] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed to be used in the embodiment description will be simply introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor, wherein:

[0014] Figure 1 It is the three-dimensional structure schematic diagram of the MEMS microphone in the embodiments of the utility model;

[0015] Figure 2 It is Figure 1 the explosion map of the MEMS microphone in the;

[0016] Figure 3 It is the section view along Figure 1 A-A line in the;

[0017] Figure 4 It is the enlarged structure schematic diagram along Figure 3 B part in the;

[0018] Figure 5 It is the section view along Figure 1 C-C line in the.

[0019] In the figure, 100, MEMS microphone; 101, accommodation space; 10, shell; 11, shell body; 12, PCB board; 121, first sound hole; 122, groove; 123, groove bottom surface; 20, ASIC chip; 30, MEMS chip; 31, substrate; 32, diaphragm; 321, air hole; 102, back cavity; 103, front cavity; 40, waterproof film; 401, fixed part; 402, middle part; 50, support plate; 501, second sound hole. 【DETAILED DESCRIPTION】

[0020] To further illustrate the embodiments, the utility model provides the drawings. These drawings are part of the utility model disclosure, which is mainly used to illustrate the embodiments, and can be combined with the related description of the specification to explain the operation principle of the embodiments. With reference to these contents, those skilled in the art should understand other possible implementation modes and advantages of the utility model. The components in the figure are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0021] The utility model will be further illustrated below in combination with the drawings and implementation modes.

[0022] The utility model provides a kind of MEMS microphone 100, in combination Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 And Figure 5 As shown in, it includes shell 10 with accommodation space 101 and the ASIC chip 20 and the MEMS chip 30 with back cavity 102 accommodated in accommodation space 101.The shell 10 includes shell body 11 and PCB board 12 with shell body 11 cover connection to form accommodation space 101.PCB board 12 is provided with first sound hole 121 that is through PCB board 12 and is communicated with back cavity 102, and first sound hole 121 is used to communicate with outside so as to flow into sound.

[0023] MEMS chip 30 includes substrate 31 and diaphragm 32 arranged on substrate 31.Diaphragm 32 divides accommodation space 101 into back cavity 102 and front cavity 103, to ensure that the air pressure of front cavity 103 and back cavity 102 is balanced, several air holes 321 will be opened on diaphragm 32, to realize the smooth flow of gas between front cavity 103 and back cavity 102.

[0024] MEMS chip 30 and ASIC chip 20 are connected by electricity, so that the signal output by MEMS chip 30 can be processed by ASIC chip 20, and ASIC chip 20 is electrically connected with PCB board 12, so that the electrical signal output by MEMS chip 30 is processed by ASIC chip 20 and outputted externally.

[0025] The MEMS microphone 100 further comprises a waterproof film 40 fixed between the MEMS chip 30 and the PCB board 12 and covering the first sound hole 121, the waterproof film 40 being used to block dust, liquid and other foreign matters in the external environment from entering the back cavity 102 of the MEMS chip 30. This helps to keep the MEMS chip 30 having a clean and tidy back cavity 102 environment, thereby ensuring that the MEMS chip 30 can quickly and accurately sense the sound pressure and convert the sound pressure into an electrical signal. At the same time, the waterproof film 40 can intercept the impact force brought by strong airflow to the MEMS chip 30, ensuring the stability of the MEMS chip 30 in converting the sound pressure into an electrical signal, thereby ensuring the stability and reliability of the MEMS microphone 100 in use. In the embodiment, the MEMS chip 30 completely covers the range of the waterproof film 40 in the orthographic projection along the direction towards the PCB board 12.

[0026] In the prior art, the waterproof film directly fixed between the MEMS chip and the PCB board will be damaged due to the direct impact of water pressure when the water pressure enters the MEMS microphone through the sound hole, so that the waterproof effect of the waterproof film is lost, thereby reducing the performance of the MEMS microphone. In order to solve the above problems, the MEMS microphone 100 further comprises a support plate 50 adhesively fixed to the PCB board 12 and covering the first sound hole 121, the support plate 50 being provided with a second sound hole 501 penetrating the support plate 50 and communicating with the first sound hole 121, wherein the first sound hole 121 and the second sound hole 501 are arranged staggered with each other. The first sound hole 121 and the second sound hole 501 are arranged staggered with each other in order to shield the water pressure entering from the first sound hole 121 through the support plate 50, buffer the impact of the water pressure on the waterproof film 40, and play a function of protecting the waterproof film 40, thereby improving the waterproof performance of the MEMS microphone 100. The number of the first sound hole 121 and the second sound hole 501 can be two or more, a plurality of first sound holes 121 being conducive to preliminarily blocking the foreign matters in the external environment from entering the MEMS microphone 100 through the first sound hole 121, and a plurality of second sound holes 501 being capable of reducing the impact of the water pressure, while each of the first sound hole 121 and each of the second sound hole 501 are arranged staggered with each other, avoiding the waterproof film 40 from being damaged due to the impact of the water pressure. The support plate 50 is a metal plate or a plastic plate, and the support plate 50 is adhesively fixed to the PCB board 12, compared with the two-layer PCB board welded by tin paste in other schemes, the product process flow is simplified.

[0027] The PCB 12 comprises a groove 122 recessed from the surface of the PCB 12 towards the support plate 50 and away from the support plate 50, the groove 122 comprises a groove bottom surface 123 towards the support plate 50, and the first sound hole 121 penetrates the PCB 12 from the groove bottom surface 123. The groove 122 can further buffer the impact force of water pressure on the waterproof film 40, reduce the phenomenon of damaging the waterproof film 40, significantly improve the reliability of the MEMS microphone 100, and realize the high performance of the MEMS microphone 100. At the same time, the groove 122 also helps to reduce the depth of the first sound hole 121 on the PCB 12, thereby well reducing the acoustic resistance of the sound propagation in the first sound hole 121, helping the sound propagation in the first sound hole 121, and thus improving the signal-to-noise ratio of the MEMS microphone 100.

[0028] In the embodiment, the waterproof film 40 covers the groove 122, and the waterproof film 40 comprises a fixed part 401 fixed to the support plate 50 and an intermediate part 402 connected with the fixed part 401, and the intermediate part is arranged in a spaced manner relative to the support plate, thereby providing a vibration space for the waterproof film 40.

[0029] In the embodiment, the ASIC chip 20 is fixed to the PCB 12. In other embodiments, the ASIC chip 20 can be embedded in the PCB 12, thereby reducing the volume of the occupied space of the ASIC chip 20 and being beneficial to the miniaturization of the product. In the embodiment, the orthogonal projection of the waterproof film 40 along the direction towards the PCB completely covers the range of the support plate 50. In other embodiments, the size of the support plate 50 can also be the same as the size of the PCB 12, and thus the ASIC chip 20 can also be fixed to the support plate 50, the ASIC chip 20 is electrically connected with the PCB 12 through the support plate 50, and the wires connected between the ASIC chip 20 and the PCB 12 can be reduced, thereby optimizing the layout of the internal lines of the MEMS microphone 100. At the same time, the support plate 50 is fixedly connected with the shell 11, and the stability of the support plate 50 can also be improved.

[0030] In order to solve the problem that the waterproof function of the waterproof film 40 is damaged due to the impact of water pressure when the waterproof film 40 is fixed between the MEMS chip 30 and the PCB 12, the utility model provides a MEMS microphone 100 comprising a support plate 50 fixed between the waterproof film 40 and the PCB 12, and a second sound hole 501 penetrating the support plate 40 is arranged on the support plate 50 at a position corresponding to the waterproof film 40, and the second sound hole 501 and the first sound hole 121 on the PCB 12 are arranged in a staggered manner, thereby effectively buffering the impact of water pressure on the waterproof film 40, protecting the waterproof function of the waterproof film 40, and further improving the acoustic performance and reliability of the MEMS microphone 100.

[0031] The above merely illustrates the embodiments of the present application, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the inventive concept, and these improvements are within the protection scope of the present application.

Claims

1. A MEMS microphone, characterized in that, It includes a housing with a receiving space, an ASIC chip housed in the receiving space, and a MEMS chip with a back cavity. The housing includes a shell and a PCB board that covers the shell to form the receiving space. The PCB board has a first sound hole that penetrates the PCB board and communicates with the back cavity. The MEMS microphone also includes a waterproof membrane that is fixed between the MEMS chip and the PCB board and covers the first sound hole. The MEMS microphone is characterized in that it further includes a support plate that is glued to the PCB board and covers the first sound hole, the support plate is provided with a second sound hole that penetrates the support plate and communicates with the first sound hole, the waterproof membrane is fixed to the surface of the support plate facing the MEMS chip and covers the second sound hole, and the first sound hole and the second sound hole are staggered.

2. The MEMS microphone according to claim 1, characterized in that, The number of the first sound holes is two or more, and each of the first sound holes and the second sound holes is staggered.

3. The MEMS microphone according to claim 1, characterized in that, The number of the second sound holes is two or more, and each second sound hole is staggered from the first sound hole.

4. The MEMS microphone according to claim 1, characterized in that, The PCB board includes a groove recessed from the surface of the PCB board toward the support plate and toward the direction away from the support plate. The support plate covers the groove. The groove includes a bottom surface facing the support plate. The first acoustic hole penetrates the PCB board from the bottom surface of the groove.

5. The MEMS microphone according to claim 1, characterized in that, The waterproof membrane includes a fixing part fixed to the support plate and an intermediate part connected to the fixing part. The thickness of the intermediate part is less than the thickness of the fixing part, and the intermediate part is spaced apart from the support plate.

6. The MEMS microphone according to claim 1, characterized in that, The support plate is sandwiched between the waterproof membrane and the PCB board, and the waterproof membrane completely covers the area of ​​the support plate along its orthographic projection toward the PCB board.

7. The MEMS microphone according to claim 1, characterized in that, The area of ​​the waterproof membrane is completely covered by the orthogonal projection of the MEMS chip along the direction toward the PCB board.

8. The MEMS microphone according to claim 1, characterized in that, The support plate is a metal plate or a plastic plate.

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