MEMS microphone and electronic equipment
By optimizing the structural design of the MEMS microphone, placing the MEMS chip in the rear cavity, reducing the volume of the front cavity, and setting up insulation and anti-static components, the problem of low signal-to-noise ratio was solved, and higher signal-to-noise ratio and low-frequency response capability were achieved.
Patent Information
- Application Number
- CN202520232166.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2035-02-13
AI Technical Summary
Existing MEMS microphones suffer from low signal-to-noise ratios due to packaging limitations, which affects sound pickup quality and audio processing performance, making it difficult to achieve accurate speech recognition or high-definition recording, especially in noisy environments.
Design a MEMS microphone structure in which a first housing and a substrate enclose a front cavity, a second housing and a substrate enclose a rear cavity, a MEMS chip is located in the rear cavity, the volume of the front cavity is smaller than that of the rear cavity, and an insulating structure, an ASIC chip and an anti-static device are provided in the front cavity to reduce environmental interference and electrostatic shock.
By reducing the remaining volume of the front cavity and increasing the remaining volume of the rear cavity, the signal-to-noise ratio is improved, stray sound interference and diaphragm noise are reduced, signal purity and low-frequency response are enhanced, and the signal-to-noise ratio and reliability of the microphone are significantly improved.
Smart Images
Figure CN223613481U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to sensor technical field, especially a kind of MEMS microphone and electronic equipment. BACKGROUND
[0002] MEMS microphone is widely applied in smart phone, earphone, tablet computer and notebook computer etc. electronic product due to its miniaturization, low power consumption, high reliability etc. In certain application scenarios, the pickup hole of MEMS microphone needs to be directly aligned with sound source, so the structure design of top sound (sound hole is located at top) is usually adopted. But due to the limitation of packaging structure, the current top sound MEMS microphone usually adopts the design of large front cavity and small rear cavity, which limits the signal-to-noise ratio of MEMS microphone to some extent. Too low signal-to-noise ratio not only affects the pickup quality, but also reduces the audio processing performance, especially in noisy environment, it is difficult to realize accurate voice recognition or high-definition recording. SUMMARY
[0003] The embodiment of the utility model provides a kind of MEMS microphone and electronic equipment, to improve the signal-to-noise ratio of MEMS microphone.
[0004] In order to achieve the above purpose, according to the first aspect of the present application, a kind of MEMS microphone is provided, comprising:
[0005] First shell is opened with first hole;
[0006] Second shell;
[0007] Substrate has opposite first surface and second surface, and is opened with second hole through first surface and second surface, MEMS chip is connected on the second surface, the projection of the MEMS chip and the second hole on the second surface overlaps, the first shell is connected with the first surface, to enclose and form first accommodating cavity, the second shell is connected with the second surface, to enclose and form second accommodating cavity, the MEMS chip is located in the second accommodating cavity;
[0008] Wherein, the first hole and the second hole are communicated, the first accommodating cavity is accommodated with first component occupying the volume of the first accommodating cavity, the remaining volume of the first accommodating cavity is less than the remaining volume of the second accommodating cavity.
[0009] Optionally, in the thickness direction of the substrate, the projection of the first hole and the projection of the second hole do not overlap.
[0010] Optionally, the first component includes an insulating structure, and the insulating structure is connected with at least one of the inner wall of the first shell and the first surface.
[0011] Optionally, the insulating structure is a silica gel structure or a heat-resistant polymer structure.
[0012] Optionally, the substrate is a circuit board, the first component includes an ASIC chip, and the ASIC chip is electrically connected to the substrate.
[0013] Optionally, the first surface is provided with a recess, and the ASIC chip is fixed in the recess.
[0014] Optionally, the substrate is a circuit board, the second surface is further connected with an ASIC chip, the MEMS chip is electrically connected to the ASIC chip, and the ASIC chip is electrically connected to the substrate.
[0015] Optionally, the first component includes an anti-static device, the anti-static device is connected to the first surface and electrically connected to the ASIC chip.
[0016] Optionally, the second housing includes a bottom plate and a surrounding plate, the surrounding plate is hollow in the middle, the bottom plate and the substrate are both circuit boards, the bottom plate and the substrate are oppositely arranged, the surrounding plate is located between the bottom plate and the substrate, and the two ends of the surrounding plate are fixedly connected with the bottom plate and the substrate, respectively, and the bottom plate and the substrate are electrically connected through the surrounding plate.
[0017] Optionally, the distance from the inner wall of the first housing away from the first surface to the first surface is less than the distance from the inner wall of the second housing away from the second surface to the second surface.
[0018] According to a second aspect of the present application, an electronic device is provided, comprising the above disclosed MEMS microphone.
[0019] One of the above technical solutions has the following advantages or beneficial effects: the first shell and the substrate jointly enclose the first accommodating cavity, and the second shell and the substrate jointly enclose the second accommodating cavity. The first shell is provided with a first hole for sound waves to enter the first accommodating cavity, and the substrate is provided with a second hole, and the MEMS chip is located in the second accommodating cavity, and the back cavity of the MEMS chip is in communication with the second hole. After the sound waves enter the first accommodating cavity, they reach the diaphragm of the MEMS chip through the second hole. The first accommodating cavity constitutes the front cavity of the MEMS microphone, and the second accommodating cavity constitutes the back cavity of the MEMS microphone. By placing the MEMS chip in the second accommodating cavity, the first accommodating cavity does not need to accommodate the MEMS chip, so the volume of the first accommodating cavity can be designed to be smaller than that of the second accommodating cavity. Further, the first assembly is arranged in the first accommodating cavity, and the first assembly can further occupy the volume of the first accommodating cavity on the premise that the first hole and the second hole are in communication, thereby effectively reducing the remaining volume of the first accommodating cavity. In this way, the remaining volume of the front cavity (the first accommodating cavity) of the MEMS microphone is reduced, and the remaining volume of the back cavity (the second accommodating cavity) of the MEMS microphone is increased. The reduction of the remaining volume of the front cavity and the increase of the remaining volume of the back cavity can make the first-order resonance peak of the frequency response of the MEMS microphone move backward, thereby improving the signal-to-noise ratio. At the same time, since the front cavity (the first accommodating cavity) is directly in contact with the environment, the reduction of the remaining volume of the front cavity (the first accommodating cavity) can reduce the interference of stray sound waves and reflected sound from the environment, thereby improving the purity of the signal, and the increase of the remaining volume of the back cavity (the second accommodating cavity) can effectively reduce the reaction force (air elasticity effect) of the air on the diaphragm when the diaphragm moves, thereby improving the low-frequency response capability of the MEMS microphone, reducing the noise interference of the diaphragm, and further significantly improving the signal-to-noise ratio of the MEMS microphone. BRIEF DESCRIPTION OF DRAWINGS
[0020] The technical solutions and other beneficial effects of the present application will become apparent from the following detailed description of the specific embodiments of the present application, combined with the accompanying drawings.
[0021] Figure 1 is a structure diagram of a MEMS microphone provided by an embodiment of the present application Figure 1 ;
[0022] Figure 2 is a structure diagram of a MEMS microphone provided by an embodiment of the present application Figure 2 ;
[0023] Figure 3 is a structure diagram of a MEMS microphone provided by an embodiment of the present application Figure 3 ;
[0024] Figure 4is a structural schematic diagram of a MEMS microphone provided by an embodiment of the present application Figure 4 ;
[0025] Figure 5 is a circuit schematic diagram of an anti-static device provided by an embodiment of the present application.
[0026] Legend of reference signs:
[0027] 10, first housing; 11, first hole;
[0028] 20, second housing; 21, bottom plate; 211, solder pad; 22, baffle; 221, conductive via;
[0029] 30, substrate; 31, second hole; 32, sink;
[0030] 40, first assembly; 41, insulating structure; 42, ASIC chip; 43, anti-static device;
[0031] 50, MEMS chip. DETAILED DESCRIPTION
[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative effort fall within the protection scope of the present application.
[0033] The embodiments of the present application disclose a MEMS microphone, referring to Figure 1 The MEMS microphone comprises a first housing 10, a second housing 20 and a substrate 30. The first housing 10 is provided with a first hole 11. The substrate 30 has a first surface and a second surface arranged oppositely, and is provided with a second hole 31 penetrating through the first surface and the second surface. The second surface is connected with a MEMS chip 50, and the projection of the MEMS chip 50 on the second surface overlaps the second hole 31. The first housing 10 is connected with the first surface to form a first accommodating cavity, and the second housing 20 is connected with the second surface to form a second accommodating cavity, and the MEMS chip 50 is located in the second accommodating cavity. Wherein, the first hole 11 and the second hole 31 are connected in communication, the first accommodating cavity accommodates a first assembly 40 occupying the volume of the first accommodating cavity, and the remaining volume of the first accommodating cavity is less than the remaining volume of the second accommodating cavity.
[0034] In some embodiments, the first housing 10 is fixedly connected with the substrate 30 by welding. In some embodiments, the first housing 10 is connected with the substrate 30 by adhesion.
[0035] In the technical solution disclosed in the application, the first shell 10 and the substrate 30 jointly form a first accommodating cavity, and the second shell 20 and the substrate 30 jointly form a second accommodating cavity. The first shell 10 is provided with a first hole 11 for sound waves to enter the first accommodating cavity. The substrate 30 is provided with a second hole 31, and the MEMS chip 50 is located in the second accommodating cavity, and the back cavity of the MEMS chip 50 is in communication with the second hole 31. After the sound waves enter the first accommodating cavity, they reach the diaphragm of the MEMS chip 50 through the second hole 31. The first accommodating cavity constitutes the front cavity of the MEMS microphone, and the second accommodating cavity constitutes the back cavity of the MEMS microphone. By placing the MEMS chip 50 in the second accommodating cavity, the first accommodating cavity does not need to accommodate the MEMS chip 50, so the volume of the first accommodating cavity can be designed to be smaller than that of the second accommodating cavity. Further, the first accommodating cavity is further provided with a first component 40, which can further occupy the volume of the first accommodating cavity on the premise that the first hole 11 and the second hole 31 are in communication, thereby effectively reducing the remaining volume of the first accommodating cavity. In this way, the remaining volume of the front cavity (the first accommodating cavity) of the MEMS microphone is reduced, and the remaining volume of the back cavity (the second accommodating cavity) of the MEMS microphone is increased. The reduction of the remaining volume of the front cavity of the MEMS microphone and the increase of the remaining volume of the back cavity can make the first-order resonance peak of the frequency response of the MEMS microphone move backward, thereby improving the signal-to-noise ratio. At the same time, since the front cavity (the first accommodating cavity) is directly in contact with the environment, the reduction of the remaining volume of the front cavity (the first accommodating cavity) can reduce the interference of stray sound waves and reflected sound from the environment, thereby improving the purity of the signal, and the increase of the remaining volume of the back cavity (the second accommodating cavity) can effectively reduce the reaction force (air elasticity effect) of the air on the diaphragm when the diaphragm moves, thereby improving the low-frequency response capability of the MEMS microphone, reducing the noise interference of the diaphragm, and further significantly improving the signal-to-noise ratio of the MEMS microphone.
[0036] In the first embodiment of the first component 40 disclosed in the application, the first component 40 includes an insulating structure 41 connected with at least one of the inner wall of the first shell 10 and the first surface. For example, with reference to Figure 1 , Figure 1 For the case where the insulating structure 41 is connected with the first surface. With reference to Figure 2 , Figure 2In the case of connecting the insulating structure 41 to the inner wall of the first shell 10. In the case of ensuring the communication between the first hole 11 and the second hole 31, the insulating structure 41 can be designed to be attached to both the inner wall of the first shell 10 and the first surface. It should be noted that the insulating structure 41 can be a silica gel structure made of silica gel or a heat-resistant polymer structure made of a heat-resistant polymer (the heat-resistant polymer can be polyimide (PI) in particular). Silica gel has good flexibility and elasticity, can absorb mechanical vibration or impact, and reduce the influence of environmental vibration on the pickup performance of the MEMS microphone. The heat-resistant polymer has low dielectric constant and excellent insulation performance, which helps to reduce the parasitic capacitance in the MEMS microphone and improve signal integrity.
[0037] In the second embodiment of the first assembly 40 disclosed in the present application, referring to Figure 3 , the first assembly 40 includes an ASIC chip 42, and the substrate 30 is a circuit board. The ASIC chip 42 is electrically connected to the substrate 30. The ASIC chip 42 is used to process electrical signals from the MEMS chip 50. The ASIC chip 42 is relatively thin, usually as low as 100 μm, so that when the ASIC chip 42 is arranged in the first accommodating cavity, the first accommodating cavity can accommodate the ASIC chip 42 without increasing the original volume. Moreover, when the ASIC chip 42 is placed in the first accommodating cavity, the remaining volume of the first accommodating cavity can be further reduced, and the volume of the MEMS chip 50 is not occupied, further improving the signal-to-noise ratio of the MEMS microphone. In some embodiments, the first surface is provided with a sink 32, and the ASIC chip 42 is fixed in the sink 32. In this way, the volume of the first accommodating cavity can be increased to accommodate the ASIC chip 42, thereby further optimizing the structural design. It should be noted that when the ASIC chip 42 is located in the first accommodating cavity, it can be flip-chip soldered (the functional area of the ASIC chip 42 faces the first surface, and the substrate of the ASIC chip 42 faces away from the first surface) on the first surface. In this way, the ASIC chip 42 can be protected from damage caused by electrostatic discharge. The ASIC chip 42 can be wrapped with light-shielding insulation glue to further avoid light noise and damage caused by electrostatic discharge. It should be noted that the first assembly 40 can include only the ASIC chip 42, or both the insulating structure 41 and the ASIC chip 42. When the first assembly 40 includes both the insulating structure 41 and the ASIC chip 42, the insulating structure 41 can wrap the ASIC chip 42.
[0038] In the third embodiment of the first assembly 40 disclosed in the present application, referring to Figure 3 and Figure 4The first component 40 includes an anti-static device 43. The anti-static device 43 can enhance the ability of the MEMS microphone to resist electrostatic discharge impact, thereby improving the reliability and stability of the device. Specifically, the anti-static device 43 is connected to the first surface and is electrically connected to the ASIC chip 42. Specifically, the anti-static device 43 can be an IPD chip (chip of integrated passive device) integrated with a capacitor and / or a resistor, or can be an anti-static circuit composed of a capacitor, a resistor, and the like. The volume of the IPD chip or the capacitor, the resistor, and the like is small, and in the case of not increasing the volume of the first accommodating cavity, it can further occupy a part of the volume of the first accommodating cavity, and reduce the remaining volume of the first accommodating cavity. It should be noted that when the anti-static device 43 is an IPD chip, the IPD chip can be connected to any transmission pin of the ASIC chip 42, which can resist the electrostatic impact from the first hole 11 into the inside of the first accommodating cavity. When the anti-static device 43 is an anti-static circuit composed of a capacitor, a resistor, and the like, the application exemplarily provides an anti-static circuit, which refers to Figure 5 The anti-static circuit includes a resistor and a capacitor, the resistor is connected in series with the transmission pin of the ASIC chip 42, and the capacitor is connected in parallel with the transmission pin of the ASIC chip 42. The anti-static circuit can be provided on each transmission pin of the ASIC chip 42, or preferably, the anti-static circuit can be provided on the power pin (VDD pin) of the ASIC chip 42.
[0039] It is worth mentioning that in order to avoid the MEMS chip 50 being impacted by electrostatic discharge, in some embodiments, the projection of the first hole 11 in the thickness direction of the substrate 30 does not overlap with the projection of the second hole 31, which can effectively avoid the impact of electrostatic discharge directly entering the MEMS chip 50 through the first hole 11 and the second hole 31, enhance the ability of the MEMS microphone to resist electrostatic discharge impact, thereby improving the reliability and stability of the device.
[0040] In some embodiments, referring to Figure 4 The first component 40 does not include the ASIC chip 42, and the ASIC chip 42 is located in the second accommodating cavity and is connected to the second surface. The substrate 30 is a circuit board, the MEMS chip 50 is electrically connected to the ASIC chip 42, the ASIC chip 42 is electrically connected to the substrate 30, and the anti-static device 43 is electrically connected to the ASIC chip 42 through the substrate 30.
[0041] In some embodiments, referring to Figure 4The second shell 20 comprises a bottom plate 21 and a surrounding plate 22, the surrounding plate 22 is hollow in the middle, and the bottom plate 21 and the substrate 30 are both circuit boards. The bottom plate 21 and the substrate 30 are oppositely arranged, the surrounding plate 22 is located between the bottom plate 21 and the substrate 30, and the two ends of the surrounding plate 22 are fixedly connected with the bottom plate 21 and the substrate 30 respectively, and the bottom plate 21 and the substrate 30 are electrically connected through the surrounding plate 22. Compared with directly opening the second accommodating cavity on the bottom plate 21, the second accommodating cavity with a larger volume can be formed by enclosing the second accommodating cavity through the bottom plate 21 and the surrounding plate 22. Further, the surrounding plate 22 is provided with a conductive through hole 221, and the substrate 30 and the bottom plate 21 are electrically connected through the conductive through hole 221. It should be noted that the surrounding plate 22 can also be directly provided as a circuit board. The surface of the bottom plate 21 away from the substrate 30 is provided with a solder pad 211, for electrically connecting other devices with the MEMS microphone.
[0042] It should be noted that in some embodiments, the distance from the inner wall of the first shell 10 away from the first surface to the first surface is less than the distance from the inner wall of the second shell 20 away from the second surface to the second surface, so that the volume of the first accommodating cavity formed by enclosing is less than the volume of the second accommodating cavity.
[0043] The embodiments of the present application also provide an electronic device, which comprises the MEMS microphone disclosed in any of the above.
[0044] In the description of the present application, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can be explicitly or implicitly included one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.
[0045] In the above embodiments, the description of each embodiment is focused on, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.
[0046] The embodiments, implementation manners and related technical features of the present application can be combined, replaced with each other without conflict.
[0047] The above is only the preferred embodiment of the present application, and does not limit the present application in any form, but any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiment, still belongs to the scope of the technical scheme of the present application.
Claims
1. A MEMS microphone, characterized in that, include: The first housing (10) has a first hole (11); Second shell (20); The substrate (30) has a first surface and a second surface disposed opposite to each other, and a second hole (31) is formed through the first surface and the second surface. A MEMS chip (50) is connected to the second surface. The projection of the MEMS chip (50) and the second hole (31) on the second surface overlaps. The first housing (10) is connected to the first surface to form a first accommodating cavity. The second housing (20) is connected to the second surface to form a second accommodating cavity. The MEMS chip (50) is located in the second accommodating cavity. The first hole (11) and the second hole (31) are connected. The first accommodating cavity contains a first component (40) that occupies the volume of the first accommodating cavity. The remaining volume of the first accommodating cavity is smaller than the remaining volume of the second accommodating cavity.
2. The MEMS microphone according to claim 1, characterized in that, In the thickness direction of the substrate (30), the projection of the first hole (11) does not overlap with the projection of the second hole (31).
3. The MEMS microphone according to claim 1, characterized in that, The first component (40) includes an insulating structure (41) connected to at least one of the inner wall of the first housing (10) and the first surface.
4. The MEMS microphone according to claim 3, characterized in that, The insulating structure (41) is a silicone structure or a heat-resistant polymer structure.
5. The MEMS microphone according to claim 1, characterized in that, The substrate (30) is a circuit board, and the first component (40) includes an ASIC chip (42), which is electrically connected to the substrate (30).
6. The MEMS microphone according to claim 5, characterized in that, The first surface has a groove (32) and the ASIC chip (42) is fixed in the groove (32).
7. The MEMS microphone according to claim 1, characterized in that, The substrate (30) is a circuit board, and an ASIC chip (42) is also connected to the second surface. The MEMS chip (50) is electrically connected to the ASIC chip (42), and the ASIC chip (42) is electrically connected to the substrate (30).
8. The MEMS microphone according to claim 5 or 7, characterized in that, The first component (40) includes an antistatic device (43) which is connected to the first surface and electrically connected to the ASIC chip (42).
9. The MEMS microphone according to claim 1, characterized in that, The second housing (20) includes a base plate (21) and a surrounding plate (22). The surrounding plate (22) is hollow in the middle. Both the base plate (21) and the substrate (30) are circuit boards. The base plate (21) and the substrate (30) are arranged opposite to each other. The surrounding plate (22) is located between the base plate (21) and the substrate (30). Both ends of the surrounding plate (22) are fixedly connected to the base plate (21) and the substrate (30) respectively. The base plate (21) and the substrate (30) are electrically connected through the surrounding plate (22).
10. The MEMS microphone according to claim 1, characterized in that, The distance from the inner wall of the first housing (10) away from the first surface to the first surface is less than the distance from the inner wall of the second housing (20) away from the second surface to the second surface.
11. An electronic device, characterized in that, Includes the MEMS microphone as described in any one of claims 1-10.