Bone conduction microphone

Abstract

The application discloses an analog bone conduction microphone, and relates to the technical field of electroacoustic conversion, which comprises a substrate circuit board, a shell, a metal gasket, a vibrator, an analog ASIC chip and a MEMS chip; the shell is connected to the substrate circuit board to form a containing cavity; the metal gasket is arranged in the containing cavity and has a first side face facing the substrate circuit board and a second side face facing away from the substrate circuit board, the metal gasket is provided with a conducting channel penetrating through the first side face and the second side face; the vibrator is arranged on the first side face and covers the conducting channel; the analog ASIC chip is arranged on the second side face; the MEMS chip is arranged on the second side face and opposite to the conducting channel; the MEMS chip receives the vibration signal transmitted by the vibrator through the conducting channel and converts the vibration signal into an electric signal and outputs the electric signal to the analog ASIC chip. The scheme can solve the problems of complex process, high manufacturing cost, and limited production yield and efficiency of the multilayer PCB stack packaging structure of the existing analog bone conduction microphone.

Description

Technical Field

[0001] This application relates to the field of electroacoustic conversion technology, and in particular to an analog bone conduction microphone. Background Technology

[0002] With the rapid development of audio technology, analog bone conduction microphones are increasingly widely used in high-noise and privacy-sensitive scenarios because they can pick up voice signals by detecting bone vibrations, thus effectively suppressing environmental noise. However, existing analog bone conduction microphones still need improvement in terms of structural design and packaging technology.

[0003] Currently, commonly used analog bone conduction microphones employ a multi-layer PCB stacking packaging method. Specifically, microelectromechanical chips and ASIC amplifier chips need to be fixed on the PCB packaging substrate. The middle layer PCB is hollowed out to form a cavity, and conductive cylinders are provided on the inner walls of its surrounding frame. Then, the upper, middle, and lower layers of circuit boards are interconnected through solder paste printing and reflow soldering processes. Finally, the vibrator and the outer shell are fixed on the top layer with glue, thus forming an analog bone conduction microphone that can receive vibration signals.

[0004] The aforementioned multilayer PCB stacked packaging structure has significant limitations in terms of manufacturing process. To achieve interlayer interconnection and cavity formation, precise positioning and multiple reflow soldering are required, making the overall packaging process quite complex. This results in limited production yield and efficiency, and a corresponding increase in manufacturing costs, thus hindering the large-scale application of analog bone conduction microphones. Summary of the Invention

[0005] The main purpose of this application is to propose an analog bone conduction microphone, which aims to solve the technical problems of complex process, high manufacturing cost, and limited production yield and efficiency of existing analog bone conduction microphones with multi-layer PCB board stacked packaging structure.

[0006] To achieve the above objectives, the simulated bone conduction microphone proposed in this application includes: Base circuit board; The outer casing is attached to the base circuit board to form a receiving cavity; A metal gasket is disposed in the receiving cavity; the metal gasket has a first side facing the substrate circuit board and a second side facing away from the substrate circuit board, and the metal gasket has a conductive channel that extends through the first side and the second side; An oscillator is disposed on the first side and covers the conduction channel; An analog ASIC chip is disposed on the second side; A MEMS chip is disposed on the second side and opposite to the conduction channel; the MEMS chip is electrically connected to the analog ASIC chip; the MEMS chip is used to receive the vibration signal transmitted by the oscillator through the conduction channel, and the MEMS chip is used to convert the vibration signal into an electrical signal and output it to the analog ASIC chip.

[0007] In one embodiment, the substrate circuit board has a plurality of functional pads on the side facing away from the housing, the functional pads including power pads, analog signal output pads and ground pads.

[0008] In one embodiment, the outline of the power pad differs from the outline of the analog signal output pad and the outline of the ground pad.

[0009] In one embodiment, the oscillator is fixedly connected to the substrate circuit board by either solder paste or adhesive.

[0010] In one embodiment, the metal gasket is fixedly connected to the oscillator by adhesive.

[0011] In one embodiment, the conductive channel is configured as a through hole, and the diameter of the conductive channel is 0.1 mm to 1.0 mm.

[0012] In one embodiment, the substrate circuit board is a single-layer PCB substrate, and the thickness of the substrate circuit board is 0.22mm~0.28mm.

[0013] In one embodiment, the oscillator includes a mass block, a support ring, and a film; the support ring is arranged around the outer periphery of the film; the mass block is disposed on the film and is located within the enclosed area of ​​the support ring.

[0014] In one embodiment, the housing is soldered to the base circuit board using solder paste.

[0015] In one embodiment, the outer shell has at least one vent hole, which communicates with the receiving cavity.

[0016] In one embodiment, the MEMS chip is electrically connected to the substrate circuit board via gold wires.

[0017] In one embodiment, the analog ASIC chip is electrically connected to the substrate circuit board via gold wires.

[0018] In one embodiment, the simulated bone conduction microphone adopts an LGA-type packaging structure, and the overall thickness of the simulated bone conduction microphone is no more than 1.3 mm.

[0019] The analog bone conduction microphone proposed in this application, compared to the complex packaging structure of existing technologies that employs multi-layer circuit board stacking, hollowed-out middle layers to form cavities, and requires conductive pillars for interlayer interconnection, utilizes a separate metal pad. The vibrator, MEMS chip, and analog ASIC chip are respectively positioned on opposite sides of the metal pad, and vibration signals are directly transmitted through conductive channels created on the metal pad. This structure eliminates the need for multi-layer circuit board stacking and interlayer interconnection processes, eliminating the need for precise multi-layer alignment and multiple reflow soldering, thus significantly simplifying the packaging process. This simplification directly leads to improved production yield and shorter manufacturing cycles, effectively reducing manufacturing costs. Furthermore, since the intermediate layers necessary for multi-layer circuit board stacking are no longer required, the overall height dimension of the analog bone conduction microphone can be reduced, facilitating the achievement of a thinner and lighter product. Furthermore, the metal spacer, acting as an isolation carrier between the oscillator and the MEMS chip and analog ASIC chip, prevents mechanical interference from oscillator vibration on the chip, allowing the oscillator, analog ASIC chip, and MEMS chip to operate independently. This reduces signal crosstalk, lowers background noise, and improves voice signal clarity. The structure of the metal spacer also provides greater flexibility in the internal spatial layout of the cavity, allowing for optimization of the rear cavity volume without increasing the overall dimensions, further improving acoustic performance. Based on the combined effects of these factors, this analog bone conduction microphone can reduce environmental noise interference while maintaining high-sensitivity voice pickup, thus improving call quality and user experience. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. 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 An exploded structural diagram of an embodiment of the analog bone conduction microphone provided in this application; Figure 2 A top-view assembly structure diagram of an embodiment of the simulated bone conduction microphone provided in this application; Figure 3 A frontal view assembly structure diagram of an embodiment of the simulated bone conduction microphone provided in this application; Figure 4 A schematic diagram of the assembly structure of an embodiment of the simulated bone conduction microphone provided in this application, viewed from a low angle. Figure 5A top view of the housing structure in one embodiment of the simulated bone conduction microphone provided in this application; Figure 6 A cross-sectional structural diagram of the housing in one embodiment of the simulated bone conduction microphone provided in this application; Figure 7 A top view of the metal pad structure in one embodiment of the simulated bone conduction microphone provided in this application; Figure 8 A schematic cross-sectional view of the metal pad in one embodiment of the simulated bone conduction microphone provided in this application; Figure 9 A top view of the oscillator structure in one embodiment of the simulated bone conduction microphone provided in this application; Figure 10 This is a front view structural diagram of the vibrator in one embodiment of the simulated bone conduction microphone provided in this application.

[0022] Explanation of icon numbers: 1. Base circuit board; 11. Functional pads; 111. Power pads; 112. Analog signal output pads; 113. Ground pads; 2. Outer shell; 21. Receiving cavity; 22. Vent hole; 3. Metal gasket; 31. First side; 32. Second side; 33. Conductive channel; 4. Oscillator; 41. Mass block; 42. Support ring; 43. Film; 5. Analog ASIC chips; 6. MEMS chips.

[0023] The realization of the purpose, functional features and advantages of this application 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 this application 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 this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] It should be noted that if the embodiments of this application 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 application 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. Therefore, 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 that simultaneously satisfies A and B. 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 in this application.

[0027] With the rapid development of audio technology, analog bone conduction microphones are increasingly widely used in high-noise and privacy-sensitive scenarios because they can pick up voice signals by detecting bone vibrations, thus effectively suppressing environmental noise. However, existing analog bone conduction microphones still need improvement in terms of structural design and packaging technology.

[0028] Currently, commonly used analog bone conduction microphones employ a multi-layer PCB stacking packaging method. Specifically, microelectromechanical chips and ASIC amplifier chips need to be fixed on the PCB packaging substrate. The middle layer PCB is hollowed out to form a cavity, and conductive cylinders are provided on the inner walls of its surrounding frame. Then, the upper, middle, and lower layers of circuit boards are interconnected through solder paste printing and reflow soldering processes. Finally, the vibrator and the outer shell are fixed on the top layer with glue, thus forming an analog bone conduction microphone that can receive vibration signals.

[0029] The aforementioned multilayer PCB stacked packaging structure has significant limitations in terms of manufacturing process. To achieve interlayer interconnection and cavity formation, precise positioning and multiple reflow soldering are required, making the overall packaging process quite complex. This results in limited production yield and efficiency, and a corresponding increase in manufacturing costs, thus hindering the large-scale application of analog bone conduction microphones.

[0030] In light of the above problems, this application proposes a simulated bone conduction microphone. Please refer to [link / reference needed]. Figure 1 The simulated bone conduction microphone includes: Base circuit board 1; The outer casing 2 is attached to the base circuit board 1 to form a receiving cavity 21; Metal gasket 3 is disposed in receiving cavity 21; metal gasket 3 has a first side 31 facing the base circuit board 1 and a second side 32 facing away from the base circuit board 1, and metal gasket 3 has a conduction channel 33 that passes through the first side 31 and the second side 32. The oscillator 4 is disposed on the first side 31 and covers the conduction channel 33; Analog ASIC chip 5 is located on the second side 32; MEMS chip 6 is disposed on the second side 32 and opposite to the conduction channel 33; MEMS chip 6 is electrically connected to analog ASIC chip 5; MEMS chip 6 is used to receive vibration signals transmitted by oscillator 4 through conduction channel 33, and MEMS chip 6 is used to convert vibration signals into electrical signals and output them to analog ASIC chip 5.

[0031] In this embodiment, the base circuit board 1 serves as the substrate of the entire analog bone conduction microphone, and its surface can be provided with conductive pads for connecting external circuits. The outer shell 2 covers the base circuit board 1, and together with the base circuit board 1, they enclose a closed receiving cavity 21; the receiving cavity 21 provides installation space for the internal components of the analog bone conduction microphone and isolates and protects the external environment.

[0032] A metal gasket 3 is disposed inside the receiving cavity 21. The metal gasket 3 has two opposing sides, namely a first side 31 and a second side 32. The first side 31 faces the base circuit board 1, that is, the first side 31 is opposite to the upper surface of the base circuit board 1; the second side 32 faces away from the base circuit board 1, that is, the second side 32 is opposite to the inner wall of the outer shell 2. A conductive channel 33 is formed on the metal gasket 3, penetrating the first side 31 and the second side 32; the conductive channel 33 can be a circular through hole, a square through hole, or other irregularly shaped through hole, and its function is to provide a physical path for the transmission of vibration signals.

[0033] The oscillator 4 is disposed on the first side 31 of the metal pad 3, and at least a portion of the oscillator 4 covers the opening of the conduction channel 33 on the first side 31. The oscillator 4 is a component capable of receiving external mechanical vibrations and generating corresponding displacement or deformation; the oscillator 4 can adopt various structural forms, such as a layer of elastic film, or a combination of film and attachment, or a cantilever beam vibrator, or a piezoelectric bending sheet, etc., as long as it can respond to external vibrations and cause pressure changes in the gas medium within the conduction channel 33. In this embodiment, the oscillator 4 can convert external skeletal vibrations into its own periodic motion.

[0034] An analog ASIC chip 5 (Application Specific Integrated Circuit) is disposed on the second side 32 of the metal pad 3. The analog ASIC chip 5 integrates signal amplification, filtering, and bias voltage generation circuits to amplify and filter the received analog electrical signal before outputting an analog audio signal. A MEMS chip 6 (Micro-Electro-Mechanical System) is also disposed on the second side 32 of the metal pad 3, with its position opposite to the conduction channel 33; that is, the sensitive area of ​​the MEMS chip 6 is aligned with the opening of the conduction channel 33 on the second side 32. The MEMS chip 6 and the analog ASIC chip 5 are electrically connected via conductive lines. Specifically, the output terminal of the MEMS chip 6 is connected to the input terminal of the analog ASIC chip 5, and the power supply and output terminals of the analog ASIC chip 5 can be further connected to corresponding pads on the substrate circuit board 1. The above electrical connection can be achieved using wire bonding, soldering, conductive adhesive bonding, etc., and is not limited here.

[0035] The following describes the operation of the simulated bone conduction microphone when receiving external vibration signals. When the user's bones vibrate mechanically due to sound emission, this mechanical vibration is transmitted through the shell 2 or the base circuit board 1 of the simulated bone conduction microphone to the vibrator 4 inside the receiving cavity 21. After receiving the mechanical vibration, the vibrator 4 itself generates a corresponding periodic displacement, that is, the vibrator 4 begins to vibrate. The vibration of the vibrator 4 directly changes the volume and pressure of the gas medium in the conduction channel 33. Specifically, when the vibrator 4 moves towards the base circuit board 1, the gas at the opening of the first side 31 of the conduction channel 33 is compressed, and the gas pressure increases; when the vibrator 4 moves away from the base circuit board 1, the gas in the conduction channel 33 expands, and the gas pressure decreases. Since the sensitive area of ​​the MEMS chip 6 is opposite to the opening of the second side 32 of the conduction channel 33, the pressure fluctuations generated in the conduction channel 33 can be directly transmitted to the inside of the MEMS chip 6.

[0036] MEMS chip 6 typically includes a vibrating diaphragm and a fixed electrode, which together form a variable capacitor structure. External pressure fluctuations can cause the diaphragm to deform, thereby changing the distance between the diaphragm and the fixed electrode, resulting in a change in capacitance. This capacitance change is converted into an analog electrical signal corresponding to the vibration signal by the conversion circuit inside MEMS chip 6. Thus, MEMS chip 6 can receive the vibration signal transmitted by oscillator 4 through conduction channel 33 and convert the vibration signal into an initial analog electrical signal.

[0037] The analog electrical signal output by MEMS chip 6 is typically weak and may contain noise. This signal is transmitted to analog ASIC chip 5 via the electrical connection between MEMS chip 6 and analog ASIC chip 5. The amplifier integrated within analog ASIC chip 5 amplifies this weak signal, the filtering circuitry within analog ASIC chip 5 removes high-frequency noise, and the charge pump within analog ASIC chip 5 provides a stable bias voltage to MEMS chip 6. The amplified and conditioned analog electrical signal has sufficient amplitude and signal-to-noise ratio to be used by subsequent external audio processing circuits. Finally, analog ASIC chip 5 transmits the processed analog audio signal to external devices via analog signal output pad 112 on the substrate circuit board 1, thus completing the bone conduction speech pickup process.

[0038] Compared to the complex packaging structure of existing technologies that employs multi-layer circuit board stacking, hollowed-out middle layers to form cavities, and conductive pillars for interlayer interconnection, the analog bone conduction microphone in this embodiment uses an independent metal pad 3. The vibrator 4, MEMS chip 6, and analog ASIC chip 5 are respectively arranged on both sides of the metal pad 3, and the vibration signal is directly transmitted through the conduction channel 33 opened on the metal pad 3. This structure eliminates the need for multi-layer circuit board stacking and interlayer interconnection processes, eliminating the need for precise multi-layer alignment and multiple reflow soldering, thus significantly simplifying the packaging process. This simplification directly leads to improved production yield and shorter manufacturing cycle, effectively reducing manufacturing costs. Simultaneously, since the intermediate layer required for multi-layer circuit board stacking is eliminated, the overall size of the analog bone conduction microphone in the height direction can be reduced, facilitating the product's thinner and lighter design. Furthermore, the metal spacer 3, acting as an isolation carrier between the oscillator 4 and the MEMS chip 6 and analog ASIC chip 5, prevents mechanical interference from the vibration of the oscillator 4, allowing the oscillator 4, analog ASIC chip 5, and MEMS chip 6 to operate independently. This reduces signal crosstalk, lowers the noise floor, and improves the clarity of the voice signal. The structure of the metal spacer 3 also provides greater flexibility for the spatial layout within the cavity 21, allowing for optimization of the rear cavity volume without increasing the overall dimensions, further improving acoustic performance. Based on the combined effects of these factors, this analog bone conduction microphone can reduce environmental noise interference while ensuring high-sensitivity voice pickup, thus improving call quality and user experience.

[0039] In one embodiment, refer to Figures 1 to 4 The substrate circuit board 1 has multiple functional pads 11 on the side facing away from the outer casing 2. The functional pads 11 include power pads 111, analog signal output pads 112 and ground pads 113.

[0040] Specifically, the power pad 111 can be used to connect an external power supply to provide the operating voltage for the analog bone conduction microphone; the analog signal output pad 112 can be used to output the analog audio electrical signal processed by the analog ASIC chip 5; and the ground pad 113 can be used to connect an external grounding line to form a complete electrical circuit.

[0041] In this embodiment, by centrally arranging the aforementioned functional pads 11 on the back of the substrate circuit board 1, the simulated bone conduction microphone can be directly soldered onto the circuit board of an external device using surface mount technology, achieving convenient and reliable electrical connection and mechanical fixation, which is beneficial to improving assembly efficiency and product integration.

[0042] In one embodiment, refer to Figure 4 The outline of the power pad 111 differs from the outline of the analog signal output pad 112 and the outline of the ground pad 113.

[0043] Specifically, the power pad 111 can be set as a square, while the analog signal output pad 112 and the ground pad 113 can be set as a rectangle or a circle; or the size of the power pad 111 is larger than the size of the other two pads; or the corners of the power pad 111 are provided with chamfers, rounded corners or other structures, while the outline of the other two pads is a complete rectangle.

[0044] The aforementioned differences in shape and contour make the power pad 111 a uniquely identifiable feature among the multiple functional pads 11. When the analog bone conduction microphone is mounted on the circuit board of an external device using surface mount technology, the pick-and-place machine can automatically identify the position and orientation of the power pad 111 through a vision recognition system, thereby accurately determining the mounting angle of the analog bone conduction microphone and avoiding problems such as reversed power, signal, and ground pins due to incorrect pad arrangement. Therefore, this foolproof design helps improve mounting yield and reduces the risk of mis-mounting during the production process.

[0045] In one embodiment, refer to Figure 1 The oscillator 4 is fixedly connected to the base circuit board 1 by either solder paste or glue.

[0046] In one embodiment, refer to Figure 1 The metal gasket 3 is fixedly connected to the oscillator 4 with glue, so that the vibration of the oscillator 4 can be transmitted to the MEMS chip 6 through the metal gasket 3.

[0047] Specifically, the oscillator 4 is fixedly connected to the base circuit board 1 by solder paste or glue; solder paste connection is suitable for reflow soldering process, which can form a strong metal bond and improve the connection reliability of the oscillator 4 in high vibration environment; glue connection can simplify the process and reduce production cost. Regardless of whether solder paste or glue is used, the oscillator 4 is fixed to the base circuit board 1, so that it can receive the external bone vibration transmitted through the base circuit board 1 or the outer shell 2 and transmit the vibration to the metal pad 3.

[0048] Meanwhile, the metal pad 3 is fixedly connected to the vibrator 4 with adhesive. The adhesive has a good elastic buffering effect, which can effectively transmit the vibration of the vibrator 4 to the metal pad 3, and absorb some high-frequency impacts, reducing the mechanical stress of the vibration of the vibrator 4 on the analog ASIC chip 5 and MEMS chip 6 on the other side of the metal pad 3, thereby improving the long-term stability of the analog bone conduction microphone.

[0049] Based on the above fixed structure, the oscillator 4, the metal pad 3 and the base circuit board 1 can form a stable mechanical coupling system to ensure high-fidelity transmission of vibration signals.

[0050] In one embodiment, refer to Figure 7 and Figure 8 The conduction channel 33 is configured as a through hole, and the diameter of the conduction channel 33 is 0.1mm~1.0mm.

[0051] In this embodiment, the conduction channel 33 is configured as a through-hole, which ensures that the air pressure changes caused by the vibration of the vibrator 4 are efficiently transmitted to the MEMS chip 6. If the aperture of the through-hole is too small, airflow will be obstructed and pressure loss will increase, resulting in significant attenuation of the vibration signal and thus reducing the sensitivity of the bone conduction microphone. If the aperture of the through-hole is too large, it may lead to low-frequency signal leakage, affecting the frequency response characteristics and reducing the fullness of voice pickup. Experiments have verified that limiting the aperture of the conduction channel 33 to the range of 0.1mm to 1.0mm can maintain a flat frequency response while ensuring good signal transmission efficiency, thereby balancing the sensitivity and sound quality of the bone conduction microphone and ensuring clear reproduction of the voice signal.

[0052] In one embodiment, refer to Figures 1 to 4 The substrate circuit board 1 is a single-layer PCB substrate with a thickness of 0.22mm~0.28mm.

[0053] Specifically, compared to multi-layer stacked structures, single-layer PCB substrates eliminate the need for interlayer alignment and conductive pillar interconnection processes, which helps reduce packaging complexity and improve production yield. By limiting the thickness of the substrate circuit board 1 to the range of 0.22mm to 0.28mm, sufficient mechanical strength and electrical performance can be guaranteed while providing a structural basis for the overall thinning of the analog bone conduction microphone, thus facilitating its integration into space-constrained electronic devices.

[0054] In one embodiment, refer to Figure 9 and Figure 10 The oscillator 4 includes a mass block 41, a support ring 42, and a film 43; the support ring 42 is arranged around the outer periphery of the film 43; the mass block 41 is disposed on the film 43 and is located within the enclosed area of ​​the support ring 42.

[0055] Specifically, the support ring 42 is arranged around the outer periphery of the film 43 to provide a fixed boundary condition for the film 43, so that the film 43 can remain taut during vibration and prevent the film 43 from shifting or loosening as a whole. The mass block 41 is disposed in the middle region of the film 43 and is surrounded by the support ring 42.

[0056] When the vibration of the external bone structure is transmitted to the oscillator 4, the mass block 41 generates inertial force due to its large mass, causing the film 43 to undergo elastic deformation. The support ring 42 can constrain the outer periphery of the film 43, so that the deformation energy is concentrated in the central region of the film 43, forming a mechanical resonant system. This structure can effectively amplify the amplitude of low-frequency vibration signals, improve the bone conduction microphone's sensitivity to picking up weak vibration signals, and at the same time, utilize the damping characteristics of the film 43 to suppress high-frequency noise interference, thereby improving the signal-to-noise ratio and output clarity of the voice signal.

[0057] In one embodiment, refer to Figure 1 , Figure 5 and Figure 6 The outer casing 2 is soldered to the base circuit board 1 using solder paste.

[0058] Specifically, solder paste soldering can form a uniform and strong metal connection layer in the reflow soldering process, so as to achieve reliable sealing and electromagnetic shielding between the outer shell 2 and the base circuit board 1, while preventing the outer shell 2 from loosening in a vibration environment.

[0059] In one embodiment, refer to Figure 1 , Figure 5 and Figure 6 The outer shell 2 has at least one vent hole 22, which is connected to the receiving cavity 21.

[0060] Specifically, during the reflow soldering surface mount process of the bone conduction microphone, the air inside the housing 21 expands due to heat, which may cause a sharp increase in internal air pressure, thereby damaging the thin film structure of the oscillator 4 or the MEMS chip 6. In this embodiment, by providing a vent 22 on the housing 2, the expanding gas can be allowed to escape, avoiding irreversible damage to sensitive components caused by packaging stress, thereby improving production yield.

[0061] In one embodiment, refer to Figure 1 The MEMS chip 6 is electrically connected to the substrate circuit board 1 via gold wires.

[0062] In one embodiment, refer to Figure 1 The analog ASIC chip 5 is electrically connected to the substrate circuit board 1 via gold wires.

[0063] Specifically, the output pads of the MEMS chip 6 can be wire-bonded to the corresponding input pads on the substrate circuit board 1, which can transmit the converted weak electrical signal to the internal traces of the substrate circuit board 1; the power supply terminal, ground terminal and signal output terminal of the analog ASIC chip 5 can also be wire-bonded to the corresponding pads on the substrate circuit board 1, thereby obtaining the working voltage and outputting the amplified analog audio signal to the external circuit.

[0064] This embodiment employs gold wire bonding, which enables low-resistance, high-reliability electrical interconnection. Furthermore, gold wire possesses excellent corrosion resistance and ductility, making it suitable for mass production wire bonding processes. When both the MEMS chip 6 and the analog ASIC chip 5 are connected to the substrate circuit board 1 via gold wires, signal transmission between them can be achieved through internal traces within the substrate circuit board 1. This eliminates the need for direct connection between the MEMS chip 6 and the analog ASIC chip 5, simplifying the packaging layout and improving signal transmission stability and production yield.

[0065] In one embodiment, refer to Figure 1 The analog bone conduction microphone adopts an LGA-type packaging structure, and the overall thickness of the analog bone conduction microphone is no more than 1.3mm.

[0066] Specifically, LGA (Land Grid Array) packaging is a surface-mount chip packaging form. Its substrate circuit board 1 has an array of functional pads 11 on the back and no external leads, making it suitable for high-density mounting. Using the LGA packaging structure, mass production can be carried out using mature automated surface mount equipment and reflow soldering processes, thereby improving production efficiency and reducing manufacturing costs.

[0067] Building upon the LGA-style packaging structure of the analog bone conduction microphone, the overall thickness of the microphone has been further reduced to less than 1.3mm. Compared to the common thickness of over 1.6mm in existing technologies, this represents a significant reduction in thickness, facilitating integration into space-constrained portable electronic devices. Simultaneously, the thinner packaging structure helps shorten the vibration transmission path and reduce energy loss, thereby further improving the sensitivity and clarity of voice pickup.

[0068] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A simulated bone conduction microphone, characterized in that, The simulated bone conduction microphone includes: Base circuit board; The outer casing is attached to the base circuit board to form a receiving cavity; A metal gasket is disposed in the receiving cavity; the metal gasket has a first side facing the substrate circuit board and a second side facing away from the substrate circuit board, and the metal gasket has a conductive channel that extends through the first side and the second side; An oscillator is disposed on the first side and covers the conduction channel; An analog ASIC chip is disposed on the second side; A MEMS chip is disposed on the second side and opposite to the conduction channel; the MEMS chip is electrically connected to the analog ASIC chip; the MEMS chip is used to receive the vibration signal transmitted by the oscillator through the conduction channel, and the MEMS chip is used to convert the vibration signal into an electrical signal and output it to the analog ASIC chip.

2. The simulated bone conduction microphone according to claim 1, characterized in that, The substrate circuit board has multiple functional pads on the side facing away from the housing. The functional pads include power pads, analog signal output pads, and ground pads.

3. The simulated bone conduction microphone according to claim 2, characterized in that, The outline of the power pad differs from the outline of the analog signal output pad and the outline of the ground pad.

4. The simulated bone conduction microphone according to claim 1, characterized in that, The oscillator is fixedly connected to the base circuit board by either solder paste or glue. And / or, the metal gasket is fixedly connected to the oscillator by adhesive.

5. The simulated bone conduction microphone according to claim 1, characterized in that, The conductive channel is configured as a through hole, and the diameter of the conductive channel is 0.1mm~1.0mm.

6. The simulated bone conduction microphone according to claim 1, characterized in that, The substrate circuit board is a single-layer PCB substrate, and the thickness of the substrate circuit board is 0.22mm~0.28mm.

7. The simulated bone conduction microphone according to claim 1, characterized in that, The oscillator includes a mass block, a support ring, and a film; the support ring is arranged around the outer periphery of the film; the mass block is disposed on the film and is located within the enclosed area of ​​the support ring.

8. The simulated bone conduction microphone according to claim 1, characterized in that, The outer casing is soldered to the base circuit board using solder paste; And / or, the outer shell is provided with at least one vent hole, which is in communication with the receiving cavity.

9. The simulated bone conduction microphone according to claim 1, characterized in that, The MEMS chip is electrically connected to the substrate circuit board via gold wires. And / or, the analog ASIC chip is electrically connected to the substrate circuit board via gold wires.

10. The analog bone conduction microphone according to any one of claims 1 to 9, characterized in that, The simulated bone conduction microphone adopts an LGA-type packaging structure, and the overall thickness of the simulated bone conduction microphone is no more than 1.3mm.

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