Bone-voiceprint sensor and electronic device

Abstract

The application discloses a bone voiceprint sensor and electronic equipment, and relates to the technical field of bone voiceprint sensors, wherein the bone voiceprint sensor comprises a substrate, a shell, a MEMS chip and a vibration pickup assembly, the shell is covered on the substrate and forms a containing cavity together with the substrate, the MEMS chip is located in the containing cavity and is electrically connected with the substrate, and the vibration pickup assembly is located in the containing cavity and is used for picking up external vibration signals and transmitting the vibration signals to the MEMS chip; the shell is provided with a recessed part recessed towards the containing cavity, the containing cavity is divided into a first sound cavity and a second sound cavity, the first sound cavity comprises a back cavity of the MEMS chip, and the recessed part is recessed to the second sound cavity. The technical scheme of the application is convenient for adjusting the volume difference of different sound cavities in the bone voiceprint sensor.

Description

Technical Field

[0001] This invention relates to the field of bone voiceprint sensor technology, and particularly to a bone voiceprint sensor and electronic device. Background Technology

[0002] With the increasing popularity of portable electronic devices such as TWS earphones and smart glasses, the demand for call noise reduction is also rising. Bone conduction sensors can directly pick up the sound signals of the user's vocal cord vibrations, effectively eliminating environmental noise and offering significant advantages in call noise reduction and voice enhancement.

[0003] The acoustic performance of a bone conduction sensor is closely related to the volume distribution of its internal first and second acoustic cavities. These cavities are located on opposite sides of the diaphragm of the MEMS chip, jointly participating in the transmission of vibration signals and pressure coupling. When the volumes of the two cavities differ significantly, the acoustic compliance on both sides of the diaphragm becomes asymmetrical, easily leading to nonlinear distortion and affecting the output signal quality. Therefore, adjusting the volumes of the two cavities to achieve the desired acoustic performance is a key issue in the design of bone conduction sensors. Summary of the Invention

[0004] The main objective of this invention is to provide a bone voiceprint sensor and electronic device that facilitates the adjustment of volume differences between different acoustic cavities in the bone voiceprint sensor.

[0005] To achieve the above objectives, the present invention proposes a bone voiceprint sensor, comprising: substrate; The outer shell covers the substrate and forms a receiving cavity with the substrate. The outer shell has a recessed portion that is recessed into the receiving cavity. The MEMS chip is located in the cavity and is electrically connected to the substrate; A vibration pickup component is located in the accommodating cavity. The vibration pickup component is used to pick up external vibration signals and transmit them to the MEMS chip. The accommodating cavity is divided into a first acoustic cavity and a second acoustic cavity. The first acoustic cavity includes the back cavity of the MEMS chip, and the recessed portion is recessed into the second acoustic cavity.

[0006] According to some embodiments of this application, the first acoustic cavity and the second acoustic cavity have the same volume.

[0007] According to some embodiments of this application, the bone voiceprint sensor further includes a support structure located in the accommodating cavity and fixed to the substrate. The support structure has a first opening and a second opening. The vibration pickup component is covered by the first opening, and the MEMS chip is covered by the second opening. The supporting structure, the MEMS chip, and the vibration pickup component divide the accommodating cavity into a first acoustic cavity and a second acoustic cavity. The supporting structure, the substrate, and the vibration pickup component enclose a vibration cavity. The vibration cavity and the back cavity of the MEMS chip are connected through the second opening to form the first acoustic cavity.

[0008] According to some embodiments of this application, the support structure is a plate-like structure.

[0009] According to some embodiments of this application, the support structure includes a first bearing portion and a second bearing portion connected along a first direction, wherein the width of the first bearing portion along a second direction is greater than the width of the second bearing portion along the second direction; The first opening and the vibration pickup component are disposed in the first support portion, and the second opening and the MEMS chip are disposed in the second support portion.

[0010] According to some embodiments of this application, the substrate is provided with pads located in the angle region between the first support portion and the second support portion, and the bone conduction sensor further includes bonding lines that are electrically connected to the pads and the MEMS chip respectively.

[0011] According to some embodiments of this application, the substrate has a groove on its surface facing the vibration pickup assembly, and the groove is part of the vibration cavity.

[0012] According to some embodiments of this application, the vibration pickup component includes: A diaphragm, the diaphragm being disposed over the first opening, the diaphragm, the supporting structure, and the substrate enclosing the vibration cavity; and A mass block, which is disposed on the diaphragm.

[0013] According to some embodiments of this application, the diaphragm is disposed on the side of the support structure facing the substrate; Alternatively, the diaphragm may be disposed on the side of the support structure opposite to the substrate.

[0014] According to some embodiments of this application, the vibration pickup assembly is provided with a balance hole connecting the vibration cavity and the second acoustic cavity.

[0015] According to some embodiments of this application, the vibration pickup component is disposed opposite to the recessed portion; And / or, the MEMS chip is misaligned with the recess.

[0016] According to some embodiments of this application, the bone conduction sensor further includes an ASIC chip, which is embedded inside the substrate and electrically connected to the substrate.

[0017] According to some embodiments of this application, the inner wall of the recess is provided with a through hole, and the bone voiceprint sensor further includes a sealing structure located in the recess, wherein the sealing structure seals the through hole.

[0018] This application also proposes an electronic device including a bone conduction sensor as described in any of the foregoing embodiments.

[0019] The technical solution of this invention involves providing a recessed portion on the outer shell that extends into the accommodating cavity. The volume of the second acoustic cavity can be adjusted by varying the degree of recess into the cavity, thereby regulating the volume difference between the first and second acoustic cavities and bringing their volumes closer together. Reducing the volume difference between the two acoustic cavities helps to minimize nonlinear distortion caused by acoustic cavity asymmetry, thus improving the acoustic performance of the bone conduction sensor. The degree of recess protrusion into the cavity can be flexibly designed according to actual needs, allowing for adjustment of the second acoustic cavity volume without altering the overall structure of the outer shell or the layout of the substrate, thus improving the convenience of acoustic cavity volume adjustment. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A structural diagram of an embodiment of the bone voiceprint sensor provided in this application; Figure 2 A top view of an embodiment of the bone conduction sensor provided in this application, with the outer casing removed; Figure 3 A structural diagram of an embodiment of the bone conduction sensor provided in this application, in which the blocking structure is removed and the diaphragm is located below the supporting structure; Figure 4 A structural diagram of an embodiment of the bone voiceprint sensor provided in this application, showing the removal of the blocking structure and the mass block having a balancing hole; Figure 5 This is a structural diagram of an embodiment of the bone conduction sensor provided in this application, mounted on an external circuit board.

[0022] Explanation of icon numbers: 100. Bone conduction sensor; 10. Substrate; 11. Groove; 12. Pad; 20. MEMS chip; 30. Housing; 31. Recess; 32. Through hole; 40. Sealing structure; 50. ASIC chip; 60. Vibration pickup assembly; 61. Diaphragm; 62. Mass block; 621. Balance hole; 70. Bonding wire; 80. Receptacle cavity; 81. First acoustic cavity; 811. Vibration cavity; 812. Back cavity; 82. Second acoustic cavity; 90. Support structure; 91. First bearing part; 92. Second bearing part; 93. First opening; 94. Second opening; 200. External circuit board.

[0023] The realization of the objective, 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 Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0026] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] With the increasing popularity of portable electronic devices such as TWS earphones and smart glasses, the demand for call noise reduction is also rising. Bone conduction sensors can directly pick up the sound signals of the user's vocal cord vibrations, effectively eliminating ambient noise and offering significant advantages in call noise reduction and voice enhancement.

[0028] The acoustic performance of a bone conduction sensor is closely related to the volume distribution of its internal first and second acoustic cavities. These cavities are located on opposite sides of the diaphragm of the MEMS chip, jointly participating in the transmission of vibration signals and pressure coupling. When the volumes of the two cavities differ significantly, the acoustic compliance on both sides of the diaphragm becomes asymmetrical, easily leading to nonlinear distortion and affecting the output signal quality. Therefore, adjusting the volumes of the two cavities to achieve the desired acoustic performance is a key issue in the design of bone conduction sensors.

[0029] Based on the above considerations, the present invention proposes a bone voiceprint sensor 100.

[0030] Please see Figure 1 In one embodiment of the present invention, the bone conduction sensor 100 includes a substrate 10, a MEMS chip 20, and a housing 30. The housing 30 covers the substrate 10 and forms a cavity 80 with the substrate 10. The MEMS chip 20 is located in the cavity 80 and is electrically connected to the substrate 10. A vibration pickup component 60 is located in the cavity 80 and is used to pick up external vibration signals and transmit them to the MEMS chip 20. The housing 30 is provided with a recessed portion 31 that is recessed into the cavity 80. The cavity 80 is divided into a first acoustic cavity 81 and a second acoustic cavity 82. The first acoustic cavity 81 includes the back cavity of the MEMS chip 20, and the recessed portion 31 is recessed into the second acoustic cavity 82.

[0031] Specifically, the substrate 10 can be a printed circuit board, a ceramic substrate 10, or a flexible circuit board, etc. The substrate 10 is provided with conductive traces and pads 12 to realize the electrical connection between the internal components of the bone voiceprint sensor 100 and the signal transmission with the external circuit.

[0032] Please see Figure 5 The lower surface of the substrate 10 is provided with external pads for soldering the bone conduction sensor 100 to an external circuit board 200, such as soldering the bone conduction sensor 100 to the motherboard of an electronic device. Conductive traces lead the electrical signals of the MEMS chip 20 and other electronic components from the upper surface of the substrate 10 to the external pads 12 on the lower surface, realizing the electrical interconnection between the sensor and the external device. The substrate 10 may also have a ground layer and a power layer to provide a stable operating voltage and ground reference for the MEMS chip 20 and the control circuit.

[0033] The outer shell 30 is disposed on the substrate 10, forming an accommodating cavity 80. The outer shell 30 can be made of metals such as copper alloy, stainless steel, or nickel alloy, or plastics such as liquid crystal polymer (LCP) or polyether ether ketone (PEEK), or ceramic or other composite materials, ensuring the structural strength and electromagnetic shielding performance of the outer shell 30. The outer shell 30 can be sealed and fixed to the upper surface of the substrate 10 by means of adhesives, solder, or laser welding.

[0034] The vibration pickup component 60 and the MEMS chip 20 form the pickup unit in the bone voiceprint sensor 100. The vibration pickup component 60 is used to respond to external vibration signals transmitted through solid media such as bones, electronic device housing 30, and motherboard, and generates a response vibration signal in response to the external vibration signal. The generated response vibration signal drives the air inside the accommodating cavity 80 to vibrate, thereby generating pressure fluctuations in the accommodating cavity 80 and acting on the diaphragm of the MEMS chip 20 to drive the diaphragm of the MEMS chip 20 to deform. The MEMS chip converts the vibration signal into an electrical signal. The MEMS chip 20 can be configured as at least one of a micromechanical capacitive sensor, a piezoelectric sensor, or a piezoresistive sensor.

[0035] The MEMS chip 20 can be electrically connected to the pads 12 on the substrate 10 through wire bonding or flip chip technology.

[0036] In some embodiments, a vibration cavity 811 is formed between the vibration pickup component 60 and the substrate 10. A support member can be provided on the side of the vibration pickup component 60 away from the substrate 10. The support member is opposite to the diaphragm 61 of the vibration pickup component 60, and a transition cavity is formed between the support member and the diaphragm 61. A first connecting hole is provided on the diaphragm 61, connecting the transition cavity and the vibration cavity 811. The support member is provided with a second connecting hole. The MEMS chip 20 is disposed on the side of the support member away from the substrate 10. The second connecting hole connects the back cavity 812 of the MEMS chip 20 and the transition cavity, thereby enabling the back cavity 812 and the vibration cavity 811 to be connected through the first connecting hole, the transition cavity, and the second connecting hole. With this configuration, when the vibration pickup component 60 responds to external vibration, it can drive the air in the vibration cavity 811 and the transition cavity to fluctuate, which is then transmitted to the back cavity of the MEMS chip 20 to drive the diaphragm of the MEMS chip 20 to deform. The MEMS chip then converts the vibration signal into an electrical signal.

[0037] In other embodiments, both the vibration pickup component 60 and the MEMS chip 20 can be disposed on the support structure 90. The vibration pickup component 60 is covered by the first opening 93 of the support structure 90, and the MEMS chip 20 is covered by the second opening 94 of the support structure. A vibration cavity 811 is formed between the support structure 90 and the substrate 10, and the second opening 94 connects the vibration cavity 811 and the back cavity 812. With this configuration, when the vibration pickup component 60 responds to external vibration, it can drive the air in the vibration cavity 811 to fluctuate, which is then transmitted to the back cavity of the MEMS chip 20 to drive the diaphragm of the MEMS chip 20 to deform. The MEMS chip then converts the vibration signal into an electrical signal.

[0038] In this embodiment, the outer shell 30 is provided with a recessed portion 31 recessed into the accommodating cavity 80. The recessed portion 31 is formed by stamping, stretching or bending a portion of the outer shell 30 toward the accommodating cavity 80, and its shape can be a circular pit, a square groove 11 or an annular groove, etc.

[0039] The recessed portion 31 can adjust the spatial distribution inside the accommodating cavity 80. The accommodating cavity 80 is divided into a first acoustic cavity 81 and a second acoustic cavity 82. The back cavity 812 of the MEMS chip 20 is part of the first acoustic cavity 81. The recessed portion 31 can be recessed into the first acoustic cavity 81 or into the second acoustic cavity 82. For example, the MEMS chip 20, the vibration pickup component 60 and the housing 30 can be arranged to form the second acoustic cavity 82, and the MEMS chip 20, the vibration pickup component 60 and the substrate 10 can be arranged to form the first acoustic cavity 81. Of course, it can also be arranged in reverse, so that the MEMS chip 20, the vibration pickup component 60 and the housing 30 can be arranged to form the first acoustic cavity 81, and the MEMS chip 20, the vibration pickup component 60 and the substrate 10 can be arranged to form the second acoustic cavity 82, that is, the back cavity 812 of the MEMS chip 20 is arranged facing away from the substrate 10.

[0040] The volume of the second acoustic cavity 82 is adjusted by the degree of indentation of the recess 31 into the accommodating cavity 80, thereby regulating the volume difference between the first acoustic cavity 81 and the second acoustic cavity 82 and making the volumes of the two acoustic cavities more similar. When the volume difference between the two acoustic cavities is small, the dynamic air pressure response on both sides of the MEMS diaphragm of the MEMS chip 20 tends to be symmetrical, which helps to reduce nonlinear distortion caused by acoustic cavity asymmetry, thereby improving the acoustic performance of the bone conduction sensor 100. The degree of indentation of the recess 31 into the accommodating cavity 80 can be flexibly designed according to actual needs, and the volume of the second acoustic cavity 82 can be adjusted without changing the overall structure of the outer shell 30 and the layout of the substrate 10, improving the convenience of acoustic cavity volume adjustment.

[0041] According to some embodiments of this application, the first acoustic cavity 81 and the second acoustic cavity 82 have the same volume.

[0042] In this embodiment, the first acoustic cavity 81 and the second acoustic cavity 82 have the same volume, which helps to make the acoustic compliance on both sides of the diaphragm 61 equal, and the gas reaction force experienced by the diaphragm 61 when it deforms to both sides under the drive of the vibration signal is symmetrical. The deformation amplitude and phase consistency of the diaphragm 61 in both directions are good, which helps to reduce nonlinear distortion caused by acoustic cavity asymmetry and improve the output signal quality of the bone conduction sensor 100.

[0043] The volume of the second acoustic cavity 82 is adjusted by the protrusion of the recess 31 into the accommodating cavity 80, so that the volumes of the first acoustic cavity 81 and the second acoustic cavity 82 tend to be equal. The degree of protrusion of the recess 31 into the accommodating cavity 80 can be adjusted according to the actual volume difference between the two acoustic cavities; the deeper the protrusion, the smaller the volume of the second acoustic cavity 82. Alternatively, the volume distribution of the first acoustic cavity 81 and the second acoustic cavity 82 in the accommodating cavity 80 can also be adjusted by the mounting orientation of the diaphragm 61 of the vibration pickup assembly 60 on the support structure 90.

[0044] Please see Figure 1 According to some embodiments of this application, the bone voiceprint sensor 100 further includes a support structure 90, which is disposed in the accommodating cavity 80 and fixed to the substrate 10. The support structure 90 has a first opening 93 and a second opening 94. The vibration pickup component 60 is covered in the first opening 93, and the MEMS chip 20 is covered in the second opening 94. The support structure 90, the vibration pickup component 60, and the MEMS chip 20 divide the accommodating cavity 80 into a first acoustic cavity 81 and a second acoustic cavity 82. The support structure 90, the vibration pickup component 60, and the substrate 10 enclose a vibration cavity 811. The vibration cavity 811 and the back cavity 812 of the MEMS chip 20 are connected through the second opening 94 to form the first acoustic cavity 81.

[0045] In this embodiment, both the vibration pickup component 60 and the MEMS chip 20 are mounted on the support structure 90. The support structure 90 can be made of metal, plastic, or composite material, and its shape can be ring-shaped, square-shaped, or other closed frame shapes. The vibration pickup component 60 is covered by the first opening 94 of the support structure 90. External vibrations can be transmitted to the vibration pickup component 60 through the substrate 10 and the support structure 90 to drive the vibration pickup component 60 to vibrate at the first opening 94. The vibration pickup component 60, the support structure 90, and the substrate 10 together form a vibration cavity 811. A second opening 94 is also provided on the support structure 90. The vibration cavity 811 and the back cavity 812 of the MEMS chip 20 are connected through the second opening 94 to jointly form a first acoustic cavity 81. Another part of the space of the accommodating cavity 80 serves as a second acoustic cavity 82. The first acoustic cavity 81 and the second acoustic cavity 82 are separated by the vibration pickup component 60, the support structure 90, and the MEMS chip 20.

[0046] The support structure 90 serves to support the diaphragm 61 and also carries the MEMS chip 20. This eliminates the need for additional support components or mounting platforms for the MEMS chip 20, reducing the number of components in the bone voiceprint sensor 100 and simplifying the assembly process. Furthermore, it allows for more space between the support structure 90 and the housing 30, which is beneficial for reducing the overall height of the bone voiceprint sensor 100 or providing greater deformation space for the vibration pickup assembly 60.

[0047] Meanwhile, the MEMS chip 20 is directly fixed to the support structure 90, and the vibration cavity 811 and the back cavity 812 of the MEMS chip 20 are directly connected through the second opening 94 on the support structure 90. The transmission path of air pressure change is short, which is conducive to improving the transmission efficiency and response speed of vibration signal.

[0048] In practical applications, when external vibrations are transmitted to the bone conduction sensor 100 through a solid medium, the external vibrations are transmitted to the vibration pickup component 60 through the support structure 90. The vibration pickup component 60 responds to the vibration signal by generating corresponding mechanical deformation or displacement, causing changes in air pressure or volume within the vibration cavity 811. Since the vibration cavity 811 is connected to the back cavity 812 of the MEMS chip 20, the changes in air pressure or volume within the vibration cavity 811 are transmitted to the back cavity 812 of the MEMS chip 20 through the connection path. This causes pressure fluctuations in the back cavity 812, which act on the diaphragm inside the MEMS chip 20, driving the diaphragm of the MEMS chip 20 to deform. These deformations are then converted into corresponding electrical signals through capacitance, piezoelectricity, or piezoresistive effects. Thus, the vibration signal is transmitted sequentially to the MEMS chip 20 via the support structure 90, the vibration pickup component 60, the vibration cavity 811, and the MEMS back cavity 812. The propagation path is short and direct, reducing signal loss and attenuation during transmission, which is beneficial for improving the sensor's sensitivity and signal-to-noise ratio.

[0049] Please refer to Figure 2 According to some embodiments of this application, the support structure 90 is a plate-like structure. This configuration gives the support structure 90 a flat surface, facilitating the placement of the MEMS chip 20 and the vibration pickup component 60. Furthermore, the plate-like structure does not occupy a large dimension in the packaging direction, which is beneficial for the thinning and lightening of the bone conduction sensor 100. In addition, it simplifies the overall structure of the support structure 90 and facilitates its fabrication.

[0050] Please see Figure 2 According to some embodiments of this application, the support structure 90 includes a first support portion 91 and a second support portion 92 connected along a first direction. The width of the first support portion 91 along the second direction is greater than the width of the second support portion 92 along the second direction. A first opening 93 and a vibration pickup component 60 are disposed on the first support portion 91, and a second opening 94 and a MEMS chip 20 are disposed on the second support portion 92.

[0051] In this embodiment, the first support portion 91 serves as the main mounting area for the vibration pickup component 60. Its larger width provides more mounting space for the vibration pickup component 60, allowing for a larger area. Increasing the area of ​​the vibration pickup component 60 improves its response sensitivity to vibration signals, thereby enhancing the signal-to-noise ratio and acoustic performance of the bone conduction sensor 100. The second support portion 92 has a smaller width along the second direction. The MEMS chip 20 is located on the second support portion 92, requiring relatively less physical mounting space. Reducing the width of the second support portion 92 effectively decreases the size of the support structure 90, reducing the space occupied by the support structure 90 in the accommodating cavity 80, thus providing more remaining space in the accommodating cavity 80 for arranging other components.

[0052] Please see Figure 2 According to some embodiments of this application, the substrate 10 is provided with a pad 12, which is located in the angle region between the first support portion 91 and the second support portion 92. The bone voiceprint sensor 100 also includes a bonding line 70 that is electrically connected to the pad 12 and the MEMS chip 20 respectively.

[0053] In this embodiment, the pad 12 is positioned in the angled region between the first support portion 91 and the second support portion 92, making full use of the corner space formed at the width change point of the support structure 90. Arranging the pad 12 for connecting the MEMS chip 20 in this region makes the layout of the various components in the accommodating cavity 80 more compact, which helps to reduce the size of the bone conduction sensor 100. Simultaneously, the pad 12 being located in the angled region, close to the MEMS chip 20, results in a shorter routing path for the bonding line 70, which helps to reduce signal loss and interference during transmission.

[0054] Please see Figure 1 According to some embodiments of this application, please refer to Figure 1 According to some embodiments of this application, the vibration pickup assembly 60 includes a diaphragm 61 and a mass block 62. The diaphragm 61 is covered by a first opening 93. The diaphragm 61, the support structure 90 and the substrate 10 surround and form a vibration cavity 811. The mass block 62 is disposed on the diaphragm 61.

[0055] In this embodiment, the edge region of the diaphragm 61 is connected to the support structure 90, and the central region of the diaphragm 61 is suspended to deform in response to vibration signals. The diaphragm 61 can be circular, elliptical, rectangular, other polygonal, or other shapes.

[0056] By placing a mass block 62 on the diaphragm 61, the weight of the vibrating structure in the vibration pickup assembly 60 can be increased, which helps to reduce the resonant frequency. The frequency band of bone vibration signals is usually located in a lower frequency range. By adjusting the resonant frequency of the vibration pickup assembly 60 to the frequency band range of bone vibration signals through the mass block 62, the vibration pickup assembly 60 can have a higher response sensitivity in this frequency band, thereby improving the bone voiceprint sensor 100's ability to pick up bone vibration signals.

[0057] The mass block 62 is disposed in the central region of the diaphragm 61, and the orthographic projection area of ​​the mass block 62 on the diaphragm 61 is smaller than the area of ​​the diaphragm 61. The orthographic projection shape of the mass block 62 can be circular, square, annular, or other shapes. The mass block 62 and the diaphragm 61 can be connected by bonding, integral molding, or other processes.

[0058] Please see Figure 3 According to some embodiments of this application, the diaphragm 61 is disposed on the side of the support structure 90 facing the substrate 10.

[0059] In this embodiment, the volume distribution of the first acoustic cavity 81 and the second acoustic cavity 82 within the accommodating cavity 80 can be adjusted by the placement position of the diaphragm 61. When the diaphragm 61 is located on the side of the support structure 90 facing the substrate 10, the space in the first opening 93 is divided into a part of the second acoustic cavity 82. The diaphragm 61 is closer to the substrate 10, resulting in a smaller volume of the first acoustic cavity 81 in the accommodating cavity 80. The deformation of the diaphragm 61 generates a larger air pressure change under the smaller volume of the first acoustic cavity 81, which is beneficial to improving the sensitivity of the bone conduction sensor 100.

[0060] Please see Figure 1 According to some embodiments of this application, the diaphragm 61 is disposed on the side of the support structure 90 facing away from the substrate 10. In this case, the space in the first opening 93 is enclosed below by the diaphragm 61, becoming part of the first acoustic cavity 81, thus increasing the portion of the accommodating cavity 80 that serves as the first acoustic cavity 81; while the space between the diaphragm 61 and the top wall of the outer shell 30 decreases, and the volume of the second acoustic cavity 82 decreases. This arrangement increases the acoustic compliance in the first acoustic cavity 81, allowing the diaphragm 61 to deform to a greater extent under the drive of a vibration signal, which is beneficial for improving the diaphragm 61's response to weak vibration signals. Simultaneously, the increased volume of the first acoustic cavity 81 provides the diaphragm 61 with more ample deformation space. Conversely, the decreased acoustic compliance in the second acoustic cavity 82 results in a larger gas reaction force on the diaphragm 61 when it deforms towards the second acoustic cavity 82, providing a certain degree of stiffness support for the diaphragm 61. This stiffness support helps the diaphragm 61 quickly return to its equilibrium position after the vibration signal stops, which is beneficial for improving the acoustic performance of the bone conduction sensor 100.

[0061] In this embodiment, the acoustic volume within the accommodating cavity 80 is allocated by flexibly changing the mounting orientation of the diaphragm 61 on the support structure 90. Based on specific acoustic simulation results or the noise characteristics of the wearing environment of the terminal device, a smaller acoustic cavity can be actively allocated to the side more critical to performance.

[0062] Please see Figure 4 According to some embodiments of this application, the vibration pickup assembly 60 is provided with a balance hole 621 that connects the vibration cavity 811 and the second acoustic cavity 82.

[0063] In this embodiment, a balancing hole 621 penetrates the vibration pickup assembly 60, connecting the vibration cavities 811 on both sides of the diaphragm 61 with the second acoustic cavity 82. The balancing hole 621 is used to balance the static gas pressure difference between the vibration cavity 811 and the second acoustic cavity 82. The balancing hole 621 provides a flow channel for the gas in the vibration cavity 811 and the second acoustic cavity 82, reducing the gas damping experienced by the vibration pickup assembly 60 during vibration, making the movement of the vibration pickup assembly 60 smoother. The reduction in gas damping results in a lower peak value of the resonance peak, a flatter frequency response curve, and a more uniform response sensitivity of the diaphragm 61 over a wider frequency band.

[0064] In some embodiments, the vibration pickup assembly 60 includes a mass block 62 and a diaphragm 61. The balancing hole 621 can pass through the mass block 62 and the diaphragm 61, or the balancing hole 621 can be provided on the diaphragm 61 and the balancing hole 621 can be misaligned with the mass block 62.

[0065] Please see Figure 1 According to some embodiments of this application, the vibration pickup component 60 is disposed opposite to the recess 31.

[0066] In this embodiment, the recessed portion 31, being recessed downwards, will inevitably encroach on the internal space of the accommodating cavity 80. By placing it above the vibration pickup component 60, the unused space above the vibration pickup component 60 is utilized, eliminating the need to increase the height of the outer shell 30 to avoid other taller internal components, thereby preventing an increase in the overall thickness of the bone conduction sensor 100.

[0067] Please see Figure 1 According to some embodiments of this application, the surface of the substrate 10 facing the vibration pickup assembly 60 is provided with a groove 11, which is part of the vibration cavity 811.

[0068] In this embodiment, the groove 11 increases the volume of the vibration cavity 811 without increasing the distance between the vibration pickup component 60 and the substrate 10. The increased volume of the vibration cavity 811 helps reduce gas damping within it, allowing the vibration pickup component 60 to deform more smoothly under the vibration signal, resulting in lower energy loss. Simultaneously, due to the increased volume of the vibration cavity 811, the vibration space of the vibration pickup component 60 is larger, and the air pressure change within the vibration cavity 811 is more gradual when the vibration pickup component 60 deforms towards the substrate 10.

[0069] In addition, the volume of the vibration cavity 811 is compensated by the opening of the groove 11, so that the distance between the vibration pickup component 60 and the substrate 10 can be kept within a small range, which is beneficial to reducing the overall height of the vibration pickup component 60.

[0070] Please see Figure 1 According to some embodiments of this application, the MEMS chip 20 is misaligned with the recessed portion 31.

[0071] In this embodiment, the recess 31 avoids the mounting position of the MEMS chip 20, reducing the risk of the recess 31 pressing on the MEMS chip 20 during the packaging process. Simultaneously, there is no need to increase the height of the casing 30 to allow the recess 31 to avoid the MEMS chip 20; furthermore, the heights of the recess 31 and the MEMS chip 20 in the thickness direction of the substrate 10 are independent, and their heights do not overlap in the thickness direction. This helps reduce the packaging height of the bone conduction sensor 100, which is beneficial for meeting the development requirements of thinner and smaller designs.

[0072] In some embodiments, the inner wall of the recess 31 is provided with a through hole 32 as a pressure equalization hole, which is used to balance the air pressure inside and outside the accommodating cavity 80 when the bone conduction sensor 100 undergoes the reflow soldering bonding process. After the reflow soldering bonding process is completed, sealant is injected to seal the through hole 32 to ensure the airtightness of the accommodating cavity 80. The recess 31 is set to be misaligned with the MEMS chip 20, so that it is far away from the MEMS chip 20 and the bonding line 70, so as to avoid glue dripping onto the surface of the MEMS chip 20 or the bonding line 70 during the dispensing process, thereby avoiding electrical short circuits or acoustic performance failures caused by glue contamination.

[0073] Please see Figure 1 According to some embodiments of this application, the bone voiceprint sensor 100 also includes an ASIC chip 50, which is embedded inside the substrate 10 and electrically connected to the substrate 10.

[0074] In this embodiment, the ASIC chip 50 (i.e., application-specific integrated circuit chip) is used to process the electrical signals output by the MEMS chip 20, such as amplifying, filtering, and performing analog-to-digital conversion on the electrical signals output by the MEMS chip 20, and then outputting the processed signals to external devices. By incorporating the ASIC chip 50 into the bone voiceprint sensor 100, the amplification and digitization of weak vibration signals can be directly performed within the bone voiceprint sensor 100, reducing signal loss and interference during transmission and improving the output signal quality of the bone voiceprint sensor 100.

[0075] Embedding the ASIC chip 50 inside the substrate 10 eliminates the need for an additional mounting area for the ASIC chip 50 on the surface of the substrate 10. The ASIC chip 50 also does not occupy the space of the accommodating cavity 80, which can reduce the overall package height of the sensor and facilitate the miniaturization design of the bone conduction sensor 100.

[0076] In addition, the bone voiceprint sensor 100 is provided with a vibration pickup component 60, and the ASIC chip 50 is embedded in the substrate 10 so that it does not occupy the space of the accommodating cavity 80. This allows the diaphragm 61 of the vibration pickup component 60 to be set larger, thereby improving the response sensitivity of the diaphragm 61 to vibration signals and thus improving the signal-to-noise ratio and acoustic performance of the bone voiceprint sensor 100.

[0077] Please see Figure 1 According to some embodiments of this application, the inner wall of the recess 31 is provided with a through hole 32, and the bone voiceprint sensor 100 also includes a blocking structure 40, which is located in the recess 31 and blocks the through hole 32.

[0078] In this embodiment, the inner wall of the recess 31 is provided with a through hole 32, which penetrates the wall thickness of the recess 31, connecting the accommodating cavity 80 to the external environment. This through hole 32 serves as a pressure equalization hole, used to balance the air pressure inside and outside the accommodating cavity 80 during the reflow soldering process of the bone conduction sensor 100, preventing damage to sensitive structures such as the MEMS chip 20 due to gas expansion inside the accommodating cavity 80 caused by high temperatures. The number of through holes 32 can be one or more. When there are multiple through holes 32, each through hole 32 can be evenly distributed on the bottom wall or side wall of the recess 31.

[0079] The sealing structure 40 is used to seal the through-hole 32 after the reflow soldering chip mounting process to ensure the airtightness of the accommodating cavity 80. This prevents sound waves conducted through the air from entering the accommodating cavity 80 through the through-hole 32, thus avoiding interference with the vibration signals picked up by the MEMS chip 20. It also prevents external dust, liquids, and other debris from entering the accommodating cavity 80 through the through-hole 32 and contaminating the MEMS chip 20 and other devices.

[0080] In some embodiments, the sealing structure 40 can be a sealant, such as epoxy resin, silicone, or UV-curable adhesive, which is applied to the recess 31 and covers the through hole 32 by dispensing or potting. After curing, the sealant seals the through hole 32. In other embodiments, the sealing structure 40 can be a plug, which is embedded in the through hole 32 or the recess 31. The plug can be made of metal, rubber, or plastic. In still other embodiments, the sealing structure 40 can be a sealing diaphragm, which is attached to the inner wall of the recess 31 and covers the through hole 32.

[0081] That is, by providing a recessed portion 31 on the outer shell 30 that is recessed into the accommodating cavity 80, and accommodating the sealing structure 40 for sealing the through hole 32 in the recessed portion 31, the sealing structure 40 does not protrude from the recessed portion 31 or only partially protrudes from the recessed portion 31, thus avoiding the overall increase in the height of the sensor due to the superposition of the height of the sealing structure 40 and the outer shell 30. This configuration not only ensures the sealing performance of the accommodating cavity 80 to prevent air-conducted sound waves from interfering with the vibration signal, but also reduces the overall packaging height of the bone conduction sensor 100, which is beneficial to the development of thinner and smaller electronic devices.

[0082] This application also proposes an electronic device including a bone voiceprint sensor 100, the specific structure of which refers to the above-described embodiments.

[0083] The electronic devices can be, but are not limited to, TWS (True Wireless Stereo) earphones, headphones, bone conduction headphones, smart glasses, smartwatches, wristbands, AR (Virtual Reality) devices, VR (Augmented Reality) devices, hearing aids, etc. The bone conduction sensor 100 is disposed within the housing of the electronic device and is used to pick up vibration signals transmitted through solid media such as bones, the electronic device housing 30, or the motherboard, and convert them into electrical signals for applications such as voice pickup, active noise reduction, call noise reduction, bone conduction communication, or health monitoring. Because the bone conduction sensor 100 of this application can adjust the volume difference between the two acoustic cavities on both sides of the MEMS chip 20 through the recessed portion 31, the volume difference between the two acoustic cavities is reduced, which helps to reduce nonlinear distortion caused by acoustic cavity asymmetry, thereby improving the acoustic performance of the bone conduction sensor 100 and giving the electronic device better acoustic performance.

[0084] Since the electronic device proposed in this application embodiment can adopt all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0085] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A bone conduction sensor, characterized in that, include: substrate; The outer shell covers the substrate and forms a receiving cavity with the substrate. The outer shell has a recessed portion that is recessed into the receiving cavity. The MEMS chip is located in the cavity and is electrically connected to the substrate; A vibration pickup component is located in the accommodating cavity. The vibration pickup component is used to pick up external vibration signals and transmit them to the MEMS chip. The accommodating cavity is divided into a first acoustic cavity and a second acoustic cavity. The first acoustic cavity includes the back cavity of the MEMS chip, and the recessed portion is recessed into the second acoustic cavity.

2. The bone conduction sensor as described in claim 1, characterized in that, The first acoustic cavity and the second acoustic cavity have the same volume.

3. The bone conduction sensor as described in claim 1, characterized in that, The bone conduction sensor also includes a support structure located in the accommodating cavity and fixed to the substrate. The support structure has a first opening and a second opening. The vibration pickup component is covered by the first opening, and the MEMS chip is covered by the second opening. The supporting structure, the MEMS chip, and the vibration pickup component divide the accommodating cavity into a first acoustic cavity and a second acoustic cavity. The supporting structure, the substrate, and the vibration pickup component enclose a vibration cavity. The vibration cavity and the back cavity of the MEMS chip are connected through the second opening to form the first acoustic cavity.

4. The bone conduction sensor as described in claim 3, characterized in that, The supporting structure is a plate-like structure.

5. The bone conduction sensor as described in claim 3, characterized in that, The support structure includes a first bearing portion and a second bearing portion connected along a first direction, wherein the width of the first bearing portion along the second direction is greater than the width of the second bearing portion along the second direction. The first opening and the vibration pickup component are disposed in the first support portion, and the second opening and the MEMS chip are disposed in the second support portion.

6. The bone conduction sensor as described in claim 5, characterized in that, The substrate is provided with pads located in the angled region between the first support portion and the second support portion. The bone conduction sensor also includes bonding lines that are electrically connected to the pads and the MEMS chip, respectively.

7. The bone conduction sensor as described in claim 3, characterized in that, The substrate has a groove on its surface facing the vibration pickup assembly, and the groove is part of the vibration cavity.

8. The bone conduction sensor as described in claim 3, characterized in that, The vibration pickup component includes: A diaphragm, the diaphragm being disposed over the first opening, the diaphragm, the supporting structure, and the substrate enclosing the vibration cavity; and A mass block, which is disposed on the diaphragm.

9. The bone conduction sensor as described in claim 8, characterized in that, The diaphragm is disposed on the side of the support structure facing the substrate; Alternatively, the diaphragm may be disposed on the side of the support structure opposite to the substrate.

10. The bone conduction sensor as described in claim 3, characterized in that, The vibration pickup assembly is provided with a balance hole connecting the vibration cavity and the second acoustic cavity.

11. The bone conduction sensor as described in claim 1, characterized in that, The vibration pickup component is disposed opposite to the recessed portion; And / or, the MEMS chip is misaligned with the recess.

12. The bone conduction sensor as described in claim 1, characterized in that, The bone conduction sensor also includes an ASIC chip, which is embedded inside the substrate and electrically connected to the substrate.

13. The bone conduction sensor as described in any one of claims 1 to 12, characterized in that, The inner wall of the recessed portion is provided with a through hole communicating with the second acoustic cavity; The bone conduction sensor also includes a sealing structure located in the recess, which seals the through hole.

14. An electronic device, characterized in that, Including the bone voiceprint sensor as described in any one of claims 1 to 13.

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