Vibration sensor and audio device

Abstract

The application discloses a kind of vibration sensor and audio equipment, it is related to audio equipment technical field, the vibration sensor includes substrate, support, vibration component, sensitive capacitor component and signal conditioning chip, substrate has connecting surface;Support is fixedly arranged in connecting surface;Vibration component includes diaphragm and mass block;Diaphragm is suspended in support, and is formed with substrate and / or support at least one cavity is collectively enclosed;Mass block is attached to diaphragm;Sensitive capacitor component includes first electrode and at least one second electrode arranged at intervals;Mass block is configured as first electrode;At least one second electrode is contained in cavity;First electrode and second electrode are electrically connected substrate;Signal conditioning chip is electrically connected substrate;Wherein, mass block can change the distance between first electrode and second electrode when vibrating with diaphragm.The application aims to reduce the overall size of sensor.

Description

Technical Field

[0001] This invention relates to the field of audio equipment technology, and in particular to a vibration sensor and an audio device. Background Technology

[0002] With the increasing popularity of TWS earbuds, call noise reduction has become a key technology. Current mainstream dual- or multi-microphone solutions are greatly affected by environmental noise and lack stability. Bone conduction sensors, however, pick up speech by detecting vibrations transmitted through bones, thus avoiding most airborne noise and providing a cleaner voice signal. Therefore, bone conduction sensors can improve call noise reduction performance in complex environments.

[0003] A bone conduction sensor is typically a microelectromechanical system that integrates multiple functions. Its core component is a MEMS microphone unit, which is responsible for directly contacting or closely fitting the user's bone surface (such as the bones behind the temples, auricle, or jawbone) to pick up mechanical vibrations transmitted through the bones by the vibration of the vocal cords.

[0004] However, in order to pick up air vibrations, traditional MEMS microphones require the design of complex perforated diaphragm structures and independent backplates. These components not only occupy a lot of vertical space, but also require additional encapsulation cavities. In the internal design of TWS earphones, where the space is already very limited, this greatly restricts the miniaturization and weight reduction of the whole device and increases the integration difficulty. Summary of the Invention

[0005] The main objective of this invention is to provide a vibration sensor and audio device that aims to reduce the overall size of the sensor.

[0006] To achieve the above objectives, the present invention provides a vibration sensor comprising: A substrate having a connecting surface; The support member is fixedly disposed on the connecting surface; A vibration assembly, comprising a diaphragm and a mass block; the diaphragm is suspended from the support member and, together with the substrate and / or the support member, forms at least one cavity; the mass block is attached to the diaphragm. A sensitive capacitor assembly, comprising a first electrode and at least one second electrode spaced apart; a mass block configured as the first electrode; at least one second electrode housed in the cavity; both the first and second electrodes being electrically connected to the substrate; and A signal conditioning chip, wherein the signal conditioning chip is electrically connected to the substrate; The mass block can change the distance between the first electrode and the second electrode when the diaphragm vibrates.

[0007] In one embodiment, the support includes a membrane support substrate, one end of which is fixedly connected to the connecting surface, and the diaphragm is disposed at the end of the membrane support substrate away from the connecting surface; The diaphragm, the film support substrate, and the substrate together form a first cavity; The second electrode is disposed on the connecting surface and accommodated in the first cavity.

[0008] In one embodiment, the support further includes a support housing disposed on the film support substrate and insulated from the film support substrate; at least a portion of the support housing is located on the side of the diaphragm away from the substrate and is spaced apart from the diaphragm; the support housing and the diaphragm together enclose a second cavity; The sensitive capacitor assembly includes two second electrodes. One second electrode is disposed on the connection surface and housed in the first cavity, and the other second electrode is disposed on the side of the support housing facing the diaphragm and housed in the second cavity.

[0009] In one embodiment, the signal conditioning chip is located on the side of the support housing facing away from the substrate, and the orthographic projection of the signal conditioning chip on the substrate at least partially overlaps with the orthographic projection of the diaphragm on the substrate.

[0010] In one embodiment, the support housing is provided with an electrical connection layer, which is electrically connected to the second electrode and the substrate.

[0011] In one embodiment, the membrane support substrate is made of a conductive material, and the membrane support substrate is electrically connected to the substrate and the mass block.

[0012] In one embodiment, the film support substrate is a conductive ring, and one end face of the conductive ring is attached to the substrate; The vibration assembly also includes at least one second wire, which electrically connects the mass block and the membrane support substrate.

[0013] In one embodiment, the vibration sensor has a first ventilation channel penetrating the mass block and the diaphragm, the first ventilation channel communicating with the first cavity.

[0014] In one embodiment, the vibration sensor further includes a housing, the housing being connected to the connecting surface, and the housing and the substrate together forming a receiving space; the housing has an equalizing hole communicating with the receiving space; The support, the sensitive capacitor assembly, and the signal conditioning chip are all housed within the receiving space.

[0015] The present invention also provides an audio device including the vibration sensor as described above.

[0016] This invention utilizes a sensitive capacitor assembly structure, where a mass block is configured as the first electrode and a second electrode is housed within a cavity formed by a diaphragm, a support member, and a substrate, along with a signal conditioning chip. This structure converts vibration into a capacitance change signal, which is then output as an electrical signal, achieving a reduction in the overall size of the vibration sensor. Specifically, when bone vibration is transmitted to the sensor, the diaphragm causes the mass block to vibrate, thereby changing the distance between the two electrodes and generating a capacitance change. The signal conditioning chip is responsible for accurately converting this capacitance change into an electrical signal that can be processed later. This design eliminates the complex perforated membrane structure and independent back electrode plate found in traditional MIC MEMS. It assigns the function of a capacitor electrode to the mass block, which was originally only used as the core of vibration sensing, and the substrate / support member, which originally only served as structural support. This "multi-purpose" design allows multiple functional components (vibrating mass, support structure, capacitor electrode plate) that were originally scattered to be highly integrated into a compact structure. This not only significantly reduces the thickness of the sensor in the vertical direction and the overall size, but also reduces the number of components and lowers product costs. Furthermore, because the electrodes are enclosed within a cavity surrounded by a diaphragm, support, and substrate, the sensor primarily senses changes in capacitance within the cavity. This makes it extremely difficult for sound wave stimuli from the external air to drive effective capacitance changes in the electrodes within the cavity, effectively isolating them. Consequently, bone conduction vibrations can be directly and efficiently transmitted to the diaphragm and mass block, driving the first electrode to shift relative to the second electrode, thus precisely changing the capacitance value. In this way, the sensor can more accurately pick up bone conduction speech signals, significantly improving the signal-to-noise ratio in noisy environments and ensuring clearer and more stable call quality. In summary, this invention, through electrode integration design, not only achieves sensor miniaturization but also improves its bone conduction sound pickup performance in complex noisy environments, resulting in higher reliability and lower cost. It provides a superior and more adaptable call noise reduction solution for micro-wearable devices such as TWS earphones. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the vibration sensor provided by the present invention; Figure 2 This is a schematic diagram of another embodiment of the vibration sensor provided by the present invention; Figure 3 This is a schematic diagram of the structure of the vibration assembly provided by the present invention; Figure 4 This is a schematic diagram of another embodiment of the vibration sensor provided by the present invention.

[0019] Explanation of icon numbers: 100. Vibration sensor; 1. Substrate; 2. Support; 21. Membrane support substrate; 21a. Conductive ring; 22. Support housing; 3. Vibration assembly; 31. Diaphragm; 32. Mass block; 321. Block body; 322. Conductive part; 33. First wire; 4. First electrode; 5. Second electrode; 6. Signal conditioning chip; 7. First ventilation channel; 8. Housing; 81. Pressure equalization hole.

[0020] 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

[0021] 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.

[0022] 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.

[0023] 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. 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 where both A and B are satisfied. 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.

[0024] This invention proposes a vibration sensor 100.

[0025] Please see Figure 1 In one embodiment, the vibration sensor 100 includes a substrate 1, a support member 2, a vibration assembly 3, a sensitive capacitor assembly, and a signal conditioning chip 6. The substrate 1 has a connection surface; the support member 2 is fixedly disposed on the connection surface; the vibration assembly 3 includes a diaphragm 31 and a mass block 32; the diaphragm 31 is suspended on the support member 2 and together with the substrate 1 and / or the support member 2, forms a cavity; the mass block 32 is attached to the diaphragm 31; the sensitive capacitor assembly includes a first electrode 4 and a second electrode 5 spaced apart; the mass block 32 is configured as the first electrode 4; the second electrode 5 is housed in the cavity; both the first electrode 4 and the second electrode 5 are electrically connected to the substrate 1; the signal conditioning chip 6 is electrically connected to the substrate 1; wherein, the distance between the first electrode 4 and the second electrode 5 can be changed when the mass block 32 vibrates with the diaphragm 31.

[0026] As can be seen, substrate 1 is typically designed as a circuit board with conductive lines. It not only carries the electrode leads of the sensitive capacitor component but also integrates the electrical connections of the signal conditioning chip 6. All capacitance change signals caused by vibration are transmitted to the signal conditioning chip 6 through the lines on substrate 1 for amplification, filtering, analog-to-digital conversion, and other processing. In addition, substrate 1 usually also has interfaces (such as pads, pins, etc.) for connecting to the outside of the sensor (such as the main circuit board of the headset), so that the processed electrical signals can be further utilized by the headset system, for example, for call noise reduction algorithms.

[0027] It should be noted that the term "suspended" in "diaphragm 31 is suspended in support member 2" means that diaphragm 31 is supported by support member 2, but the area below it remains suspended and does not directly contact support member 2. This design provides the necessary space for the free vibration of diaphragm 31, ensuring that it can effectively respond to external vibrations. Therefore, under the above structural design, the specific form of support member 2 is diverse. It can be a structure with a back cavity (such as a ring or frame shape), or a flexible beam, etc. Its core objective is to provide support for diaphragm 31 and ensure that the movement of diaphragm 31 is not obstructed.

[0028] In the design of this vibration sensor 100, the construction of the "cavity" is a key structural feature, which is directly related to the formation of the sensitive capacitance and the working environment. This cavity is a closed or semi-closed micro-space formed by the cooperation of at least two of the three core structural components: diaphragm 31, substrate 1, and support member 2. For example, "diaphragm 31 + substrate 1": the diaphragm 31 acts as a movable "lid," bending downwards or fitting together with the relatively fixed surface of the substrate 1 to form an approximately closed space with an upper opening (defined by the edge of the diaphragm 31) and a lower closing (defined by the surface of the substrate 1). This structure is relatively simple and easy to manufacture. Alternatively, "diaphragm 31 + support member 2": the support member 2 can be designed with a certain height or a specific shape (e.g., a hook shape, with the diaphragm 31 located at the opening of the hook), thus forming a space together with the surface of the diaphragm 31. Or, "diaphragm 31 + substrate 1 + support member 2": the support member 2 provides the sidewalls, the substrate 1 provides the bottom surface, and the diaphragm 31 provides the top surface.

[0029] In addition, regarding the "mass block 32 being configured as the first electrode 4", there are two implementation methods: one is that the mass block 32 itself is made of conductive material (such as metal or doped semiconductor), and can be directly used as the first electrode 4 without additional processing; the other is that the mass block 32 consists of two parts: a non-conductive block body 321 (mainly providing inertial mass) and a conductive part 322 attached thereto. In this case, the conductive part 322 (usually a metal or heavily doped polycrystalline silicon layer) performs the function of the first electrode 4. This design allows the block body 321 to be made of non-conductive material, while the electrode is precisely constructed by adding a conductive layer, providing greater design flexibility.

[0030] It should also be noted that, since the second electrode 5 needs to be combined with the first electrode 4 to form a capacitor, and the second electrode 5 needs to be positioned within the cavity while maintaining a certain air gap with the first electrode 4, the second electrode 5 can be positioned on the connecting surface of the substrate 1, forming an air gap cavity with the mass block 32 suspended thereon; or, the second electrode 5 can be positioned on the surface of the support member 2 facing the diaphragm 31, with an air gap cavity formed between the mass block 32 and the support member 2. Of course, other placement positions and methods that meet the above conditions are also possible, and are not specifically limited here.

[0031] In the above structure, there are various structures and methods for realizing the electrical connection between the first electrode 4 (mass block 32) and the second electrode 5 and the substrate 1 (which is then connected to the signal conditioning chip 6), and the electrical connection between the signal conditioning chip 6 and the substrate 1. For example, when a relatively large wiring space is required for the signal conditioning chip 6, the connection distance is relatively long. Metal wire bonding technology can be used. By preparing tiny metal contact points on the electrode and chip pads, and then using metal wires (usually gold wires or copper wires) for precision welding, weak capacitance change signals or drive signals can be effectively transmitted out or introduced into the chip. For example, for cases where the connection distance is short, conductive adhesive bonding or welding can be considered.

[0032] In this embodiment, by employing a sensitive capacitor assembly structure in which the mass block 32 is configured as the first electrode 4 and the second electrode 5 is housed within a cavity formed by the diaphragm 31, the support member 2, and the substrate 1, and a signal conditioning chip 6 is used to convert vibration into a capacitance change signal and ultimately output it as an electrical signal, the overall size of the vibration sensor 100 can be reduced. Specifically, when bone vibration is transmitted to the sensor, the diaphragm 31 drives the mass block 32 to vibrate, thereby changing the distance between the two electrodes and generating a capacitance change. The signal conditioning chip 6 is responsible for accurately converting this capacitance change into an electrical signal that can be processed subsequently. This design eliminates the complex perforated membrane structure and independent back electrode plate found in traditional MIC MEMS. Instead, it assigns the function of capacitive electrodes to the mass block 32, which originally served only as the core of vibration sensing, and the substrate 1 / support member 2, which originally only provided structural support. This "multi-purpose" design allows multiple functional components (vibrating mass, support structure, and capacitive electrode plate) that were originally scattered to a highly integrated structure. This not only significantly reduces the thickness of the sensor in the vertical direction and the overall size, but also reduces the number of components and lowers product costs. Furthermore, since the electrodes are enclosed within a cavity surrounded by the diaphragm 31, support member 2, and substrate 1, the sensor primarily senses changes in capacitance within the cavity. This makes it extremely difficult for sound wave stimuli from the outside air to drive effective capacitance changes in the electrodes within the cavity, thus effectively isolating them. Consequently, vibrations transmitted through the bones can be directly and efficiently transmitted to the diaphragm 31 and mass block 32, driving the first electrode 4 to shift relative to the second electrode 5, thereby precisely changing the capacitance value. This design enables the sensor to more accurately pick up bone conduction voice signals, significantly improving the signal-to-noise ratio in noisy environments and ensuring clearer and more stable call quality. In summary, this invention, through electrode integration design, not only achieves sensor miniaturization but also fundamentally improves its bone conduction sound pickup performance in complex noisy environments, resulting in higher reliability and lower cost. It provides a superior and more adaptable call noise reduction solution for micro-wearable devices such as TWS earphones.

[0033] Furthermore, it is easy to understand that the material selection and structural design of the first electrode 4 and the second electrode 5 constituting the capacitor are crucial. Typically, the first electrode 4 plays a relatively fixed role as a reference, while the second electrode 5 is closely connected to the mass block 32, or to the mass block 32 itself, thus allowing it to move with external excitation. The core requirement for both the first electrode 4 and the second electrode 5 is excellent conductivity to ensure extremely low self-resistance.

[0034] In terms of morphology, the first electrode 4 and the second electrode 5 are typically configured as strips or sheets. Strip or sheet structures are generally easier to manufacture precisely and mass-produce using semiconductor or micro / nano fabrication processes such as photolithography, deposition, and etching. This not only facilitates alignment and connection with other planar components (such as substrate 1, conductive ring 21a, film support substrate 21, etc.), but also helps in designing reasonable current paths, reducing contact resistance and line resistance, thereby improving conductivity. In addition, by adjusting the length, width, and spacing of the first electrode 4 and the second electrode 5, parasitic parameters such as capacitance and inductance can be precisely controlled, optimizing the electrical characteristics of the device. Furthermore, the shapes of the first electrode 4 and the second electrode can be flexibly designed according to specific applications and manufacturing processes, and are not limited here.

[0035] Please see Figure 2 In one embodiment, the support member 2 includes a film support substrate 21, one end of which is fixedly connected to the connection surface, and a diaphragm 31 is disposed at the end of the film support substrate 21 away from the connection surface; the diaphragm 31, the film support substrate 21 and the substrate 1 together form a first cavity; the second electrode 5 is disposed on the connection surface and accommodated in the first cavity.

[0036] In this embodiment, the film support substrate 21 is typically designed in a circular shape, or other ring-shaped structures (e.g., square rings, elliptical rings, etc.). One end face of the ring-shaped film support substrate 21 is firmly fixed to the connecting surface of the substrate 1, while the diaphragm 31 is disposed at the end of the film support substrate 21 away from the substrate 1 (i.e., the diaphragm 31 is disposed in the central opening area of ​​the ring structure or attached to the end face of the film support substrate 21), thereby allowing the central portion of the diaphragm 31 to vibrate freely. In this way, the diaphragm 31 (as the central moving part), the ring-shaped film support substrate 21 (as the support and sidewall), and the substrate 1 (as the bottom) together enclose the first cavity. At the same time, the second electrode 5, which serves as the other electrode plate of the sensitive capacitor, is disposed on the connecting surface of the substrate 1, and its position is located inside the first cavity, that is, it typically covers the surface of the substrate 1 and is surrounded by the diaphragm 31 and the support substrate.

[0037] Thus, the annular membrane support substrate 21 can provide relatively uniform support force around the diaphragm 31, and the characteristics of its membrane (such as thickness and material) determine the stiffness and flexibility of the support, which directly affects the natural frequency and vibration mode of the diaphragm 31. Therefore, by optimizing the size and material of the annular support substrate, the vibration characteristics of the diaphragm 31 can be better controlled to match specific acoustic requirements (for example, for call noise reduction, a specific frequency response may be required).

[0038] In one embodiment, the vibration sensor 100 has a first ventilation channel 7 that runs through the mass block 32 and the diaphragm 31 and communicates with a first cavity.

[0039] In this embodiment, the formation of the first ventilation channel 7 is actually achieved by drilling a hole in the mass block 32 and the diaphragm 31, so that there is an airflow path between the first cavity and the outside. Its main purpose is to reduce the damping effect of the compression membrane in the air gap, thereby improving the overall performance of the vibration sensor 100.

[0040] When the diaphragm 31 (or mass block 32) vibrates, the air gap between the first electrode 4 and the second electrode 5 changes periodically. When the air gap decreases, the air trapped in the gap is compressed; when the air gap increases, the air needs to expand or be replenished from the outside. This compression and expansion of the air generates a counterforce, hindering the rapid movement of the diaphragm 31. This effect is called diaphragm damping, which consumes vibration energy and reduces the sensitivity of the sensor. By setting the first ventilation channel 7, when the air gap decreases, the mass block 32 moves closer to the second electrode 5, the air gap space becomes smaller, and the compressed air in the first cavity can flow to other spaces through the first ventilation channel 7, effectively preventing a sharp increase in air pressure in the air gap, thereby reducing compression resistance. When the air gap increases, the mass block 32 moves away from the second electrode 5, the air gap space becomes larger, and external air can smoothly enter the first cavity through the first ventilation channel 7 to increase the air gap, replenishing the vacuum or low-pressure area generated by expansion, thereby reducing expansion resistance or suction. In this way, the damping force of the extrusion membrane that hinders the free vibration of the diaphragm 31 is significantly reduced, allowing the diaphragm 31 to respond to external vibrations more quickly and with greater amplitude, thereby improving the sensitivity of the sensor, improving the dynamic response range, and optimizing the performance of the vibration sensor 100.

[0041] Furthermore, to ensure the dynamic stability of the vibration assembly 3, the first ventilation channel 7 is preferably located near the center of mass of the mass block 32 and the diaphragm 31 assembly. This significantly reduces the reaction torque generated by airflow through the ventilation channel during vibration, avoiding unnecessary lateral disturbances or torsional forces on the diaphragm 31, and helping to ensure that the diaphragm 31 vibrates only in a direction perpendicular to the diaphragm surface. This directly improves the sensor's vibration linearity, frequency response flatness, and signal measurement accuracy, enabling the sensor to respond more stably and accurately to external vibrations or sound pressure changes.

[0042] Please continue reading. Figure 2 In one embodiment, the support member 2 further includes a support housing 22, which is disposed on the film support substrate 21 and is insulated from the film support substrate 21; at least a portion of the structure of the support housing 22 is located on the side of the diaphragm 31 away from the substrate 1 and is spaced apart from the diaphragm 31; the support housing 22 and the diaphragm 31 together form a second cavity; the sensitive capacitor assembly includes two second electrodes 5, one second electrode 5 is disposed on the connection surface and housed in the first cavity, and the other second electrode 5 is disposed on the side of the support housing 22 facing the diaphragm 31 and housed in the second cavity.

[0043] In this embodiment, the support housing 22 is not completely "pressed" onto the diaphragm 31, but a part of the structure is "suspended" above the diaphragm 31 at a certain distance. This "suspended" part together with the diaphragm 31 forms a second cavity. The formation of the second cavity provides physical space for setting the second electrode, and makes the movement of the mass block 32 affect not only its distance from the second electrode 5 set on the substrate 1, but also its distance from the second electrode 5 set on the support housing 22, so as to create a structural basis for realizing the differential capacitor structure.

[0044] Furthermore, the insulation between the support housing 22 and the film support substrate 21 is to ensure that the two electrodes constituting the dual-capacitor structure are electrically isolated, preventing short circuits, ensuring the independence and measurement accuracy of the first and second capacitors, reducing parasitic effects and interference, thereby enabling subsequent differential signal processing to be performed effectively, ultimately improving the overall performance of the sensor. Here, "insulation" can be understood as: to ensure that the two independent chambers (capacitors) can be used normally and do not interfere with each other, a good wall (insulating layer) is needed to separate them.

[0045] To achieve insulation, an insulating adhesive / insulating filler can be provided between the support housing 22 and the film support substrate 21; or, during the manufacturing process, an insulating material (such as silicon dioxide, silicon nitride, etc.) can be deposited or grown on the film support substrate 21 first, and then the support housing 22 structure can be formed by etching, bonding or other processes; or, the support housing 22 can be set as an insulating material, and a conductive layer can be provided on the support housing 22 as the second electrode 5.

[0046] Specifically, one capacitor (first capacitor C1) is formed by the mass block 32 and the second electrode 5 on the substrate 1, while the other capacitor (second capacitor C2) is formed by the mass block 32 and the second electrode 5 on the supporting housing 22. When external sound pressure is applied to the diaphragm 31, the diaphragm 31 moves along with the mass block 32. This movement simultaneously affects the capacitance values ​​of both C1 and C2. For example, when the diaphragm 31 moves closer to C1, the capacitance value of C1 increases, but at the same time, the diaphragm 31 moves away from C2, causing the capacitance value of C2 to decrease. This reverse or specific coupling change between C1 and C2 is the basis for differential processing to effectively extract the target acoustic signal.

[0047] However, besides the target sound pressure level, there are other external factors, such as thermal expansion and contraction caused by temperature changes, or physical shocks and vibrations to the equipment. These factors simultaneously and in the same direction affect both C1 and C2. The interference signals generated by these factors are called common-mode interference. If only the value of a single capacitor (C1 or C2) is measured, these common-mode interferences will be directly superimposed on the effective signal, thereby reducing the signal-to-noise ratio (SNR) and measurement accuracy. Since the common-mode interference affects C1 and C2 simultaneously and in the same direction, calculating their difference (C1 - C2) or ratio (C1 / C2) can significantly suppress or even eliminate these interference terms. For the effective signal caused by the target sound pressure level, since the changes in C1 and C2 are opposite or specifically coupled, their difference or ratio will amplify the effective signal. Therefore, through this dual-capacitor structure and differential processing method, common-mode interference can be effectively filtered out while enhancing the target acoustic signal, ultimately achieving high signal-to-noise ratio and high-precision measurement.

[0048] In one embodiment, the mass block 32 is disposed in the first cavity.

[0049] by Figure 1For example, one side of the substrate 1 is positioned close to the vibration source, and the first cavity and the second cavity are arranged vertically. Placing the mass block 32 in the lower first cavity lowers its center of gravity. Due to the low center of gravity, when the sound pressure acts perpendicularly on the diaphragm 31, the main driving force is to overcome the electrostatic force / capacitance change force between the diaphragm 31 and the electrode, causing the diaphragm 31 and the mass block 32 to translate vertically as a whole. Even if there are some minor non-perpendicular interference forces, the low center of gravity structure is better able to resist the resulting rotational tendency. This ensures that the motion mode of the diaphragm 31 is closer to the ideal single-degree-of-freedom vertical motion.

[0050] In one embodiment, the vibration sensor 100 also has a second ventilation duct that extends through the support housing 22 and communicates with the second cavity.

[0051] In this embodiment, the second ventilation duct is formed by drilling a hole in the support housing 22 and the second motor, so that there is an airflow path between the second cavity and the outside. Its main purpose is to reduce the damping effect of the compression membrane in the air gap, thereby improving the overall performance of the vibration sensor 100.

[0052] When the diaphragm 31 (or mass block 32) vibrates, the air gap between the first electrode 4 and the second electrode 5 changes periodically. When the air gap decreases, the air trapped within it is compressed; when the air gap increases, the air needs to expand or be replenished from the outside. This compression and expansion of the air generates a counterforce, hindering the rapid movement of the diaphragm 31. This effect is called diaphragm damping, which consumes vibration energy and reduces the sensor's sensitivity. By providing a second ventilation channel, when the air gap decreases, the mass block 32 moves closer to the second electrode 5, reducing the air gap space. The compressed air in the second cavity can flow to the outside through the second ventilation channel, effectively preventing a sharp increase in air pressure within the air gap, thereby reducing compression resistance. When the air gap increases, the mass block 32 moves further away from the second electrode 5, increasing the air gap space. External air can smoothly enter the second cavity through the second ventilation channel to increase the air gap, replenishing the vacuum or low-pressure area generated by expansion, thereby reducing expansion resistance or suction. In this way, the damping force of the extrusion membrane that hinders the free vibration of the diaphragm 31 is significantly reduced, allowing the diaphragm 31 to respond to external vibrations more quickly and with greater amplitude, thereby improving the sensitivity of the sensor, improving the dynamic response range, and optimizing the performance of the vibration sensor 100.

[0053] Of course, in other embodiments, the first ventilation channel 7 and the second ventilation channel can be provided simultaneously. Thus, when the vibration of the diaphragm 31 causes a change in the volume of the first or second cavity, air can not only flow through the first ventilation channel 7 within the first cavity, but also achieve more effective pressure balance with the second cavity and even the external environment (or at least the space connected to the second cavity) through the second ventilation channel. This significantly reduces the instantaneous pressure change amplitude inside the first cavity caused by the movement of the diaphragm 31, significantly weakening the damping effect of the compression membrane. The pressure in the air gap can more quickly converge to the pressure outside or in the second cavity, reducing the "air cushion" effect that hinders the movement of the diaphragm 31, thereby further improving the sensor's sensitivity.

[0054] Please see Figure 1 and Figure 2 As can be seen, in the above embodiments, the position of the signal conditioning chip 6 is very flexible. For example, it can be located on the side or edge of the substrate 1 and connected to the pads on the substrate 1 by wire bonding or flip-chip bonding. Another option is to place it on the back of the substrate 1, that is, on the side away from the diaphragm 31, and use the metallized vias or edge connection paths inside the substrate 1 to guide the signal from the sensitive capacitor component to the chip.

[0055] However, with the increasing demand for miniaturization and lightweighting of electronic devices, in order to achieve a more compact layout and make full use of vertical space, in one embodiment, the signal conditioning chip 6 is located on the side of the support housing 22 facing away from the substrate 1, and the orthographic projection of the signal conditioning chip 6 on the substrate 1 and the orthographic projection of the diaphragm 31 on the substrate 1 are at least partially overlapped.

[0056] In this embodiment, "the projection area of ​​the signal conditioning chip 6 on the substrate 1 and the projection area of ​​the diaphragm 31 on the substrate 1 are at least partially overlapping each other". This means that the chip, which may have originally occupied the edge or back of the substrate 1, is now "stacked" in the space directly above the diaphragm 31. This frees up the area occupied by the signal conditioning chip 6 on the substrate 1, thereby greatly improving space utilization.

[0057] Furthermore, a protective layer (such as protective adhesive or protective paint) can be applied to the signal conditioning chip 6 to enhance its environmental resistance and prevent moisture, dust, or physical damage.

[0058] Of course, the second electrode 5 does not need to be set on the support housing 22, so that the support housing 22 only serves as a basic structural support and chip mounting function.

[0059] For example, in one embodiment, the support member 2 further includes a support housing 22, which is disposed on the film support substrate 21 and is insulated from the film support substrate 21; at least a portion of the structure of the support housing 22 is located on the side of the diaphragm 31 facing away from the substrate 1; the signal conditioning chip 6 is located on the side of the support housing 22 facing away from the substrate 1, and the orthographic projection of the signal conditioning chip 6 on the substrate 1 at least partially overlaps with the orthographic projection of the diaphragm 31 on the substrate 1.

[0060] In this embodiment, since the support housing 22 no longer needs to serve as the mounting surface for the second electrode 5, it does not need to form a second cavity together with the diaphragm 31. Therefore, the support housing 22 can be designed with a simpler shape, such as a plate, sheet, or block. Furthermore, to avoid short circuits or the introduction of unnecessary parasitic capacitance, the support housing 22 needs to be insulated from the film support substrate 21. This requires the support housing 22 to be made of an insulating material, or an insulating layer to be provided at the connection between the support housing 22 and the film support substrate 21, such as using insulating adhesive to bond the support housing 22 and the film support substrate 21, thereby ensuring the accuracy and stability of the change in the first capacitance C1.

[0061] In one embodiment, the support housing 22 is provided with an electrical connection layer, which is electrically connected to the second electrode 5 and the substrate 1.

[0062] In this embodiment, by directly integrating the electrical connection layer on the support housing 22, the need for additional connecting wires, lead frames or other connectors to connect the second electrode 5 is eliminated, making the overall structure simpler and more compact.

[0063] It should be noted that the choice of electrical connection layer is indeed very broad. The specific material or technology chosen largely depends on the specific requirements of the application scenario regarding conductivity, cost, durability, manufacturability, and environmental adaptability. For example, the electrical connection layer can be a gold-plated layer formed on the support housing 22. Gold has extremely low resistivity and is an excellent conductive material; at the same time, it is also a chemically stable precious metal that is not easily oxidized or corroded. Forming an electrical connection layer by gold plating not only ensures very low contact resistance and conduction resistance between the second electrode 5 and the substrate 1, guaranteeing efficient signal transmission and stable power supply, reducing signal loss and heat generation, but also effectively protects the underlying substrate (i.e., the support housing 22) from reactions with air, moisture, or other environmental factors, thereby preventing degradation or failure of electrical connection performance and ensuring long-term reliable connection. Of course, in addition to gold plating, depending on different needs, the electrical connection layer can also be a copper-plated layer, a silver-plated layer, a tin-plated layer, or a conductive adhesive layer, among other forms.

[0064] Please see Figure 3In one embodiment, the membrane support substrate 21 is made of a conductive material and is electrically connected to the substrate 1.

[0065] It should be noted that the film support substrate 21 can be a metal material with conductive properties, such as copper, aluminum, silver, gold, etc.

[0066] In this embodiment, the film support substrate 21 is used as part of the signal path, enabling the direct transmission of the induced signal generated by the first capacitor to the processing circuitry on the substrate 1. This eliminates the need for separate connecting electrodes or wires, simplifying the overall structure. Simultaneously, the film support substrate 21 is directly electrically connected to the substrate 1, forming a more stable and direct electrical path. This integrated connection method is generally more reliable than using additional wires or connectors, and reduces the occurrence of potential problems such as poor contact.

[0067] Please continue reading. Figure 3 In one embodiment, the film support substrate 21 is a conductive ring 21a, and one end face of the conductive ring 21a is attached to the substrate 1; the vibration component 3 also includes at least one first wire 33, which is electrically connected to the first electrode 4 and the film support substrate 21.

[0068] In this embodiment, the conductive ring 21a is tightly bonded to the substrate 1 by means of pressing, welding, or conductive adhesive bonding. This structural design not only simplifies the overall structure and reduces additional fixing components, but more importantly, it directly constructs a stable and low-impedance electrical path, thereby significantly improving the reliability of the electrical connection. Meanwhile, the first electrode 4 (mass block 32) can be directly connected to the film support substrate 21 via the first wire 33, which optimizes signal transmission efficiency, effectively reduces contact resistance and signal loss, and ensures that the signal sensed or applied by the mass block 32 can be transmitted efficiently and with low noise, improving the high sensitivity and stability of the sensitive capacitor assembly.

[0069] It should be noted that the first conductor 33 can be a metal wire with good conductivity, such as gold wire, copper wire, silver wire, or aluminum wire. The specific material selected usually needs to be comprehensively considered based on factors such as electrical performance requirements (e.g., conductivity, contact resistance), mechanical performance requirements (e.g., fatigue resistance, ductility), corrosion resistance, and cost in the actual application scenario, and no specific limitation is made here.

[0070] Furthermore, in one embodiment, the vibration component 3 includes four first wires 33, which are connected in a cross shape to the mass block 32 and the membrane support substrate 21.

[0071] In this embodiment, the cross-shaped symmetrical layout helps to balance the forces on the mass block 32 in all directions, which can reduce unexpected vibration modes (such as tilting and twisting) and improve the stability and reliability of the vibration component 3.

[0072] Please see Figure 1 and Figure 2 In one embodiment, the vibration sensor 100 further includes a housing 8, the housing 8 is connected to a connecting surface, and the housing 8 and the substrate 1 together form a receiving space; the housing 8 is provided with an equalizing hole 81 that communicates with the receiving space; the support member 2, the sensitive capacitor assembly and the signal conditioning chip 6 are all disposed in the receiving space.

[0073] In this embodiment, the housing space formed by the outer shell 8 and the substrate 1 provides robust physical protection for the internal support 2, sensitive capacitor assembly, and signal conditioning chip 6, preventing damage to the internal components from the external environment (such as dust, moisture, and physical impact) and ensuring the stability of the overall structure. The pressure equalization holes 81 on the outer shell 8 allow for pressure exchange between the internal housing space and the external environment, preventing excessive pressure differences between the internal and external environments due to temperature changes and other factors. This avoids pressure impacts on the internal structure (especially the sensitive capacitor gaps), ensuring stable sensor operation under various environments. Furthermore, during the user's reflow soldering process, the pressure equalization holes 81 play a crucial role in balancing the internal air pressure, preventing component damage or soldering defects caused by pressure differences between the internal and external air sources.

[0074] It should be noted that since different devices or systems have different requirements for the installation space and shape of the sensor, the shape of the housing 8 can be freely selected or designed according to various factors such as specific application scenarios, installation space, heat dissipation requirements, cost considerations and aesthetics, without being bound by a certain specific structure, thereby optimizing the overall design.

[0075] Please see Figure 4 In one embodiment, the support member 2 includes a film support substrate 21 and a support housing 22. One end of the film support substrate 21 is fixedly connected to the connection surface, and the diaphragm 31 is disposed at the end of the film support substrate 21 away from the connection surface. The diaphragm 31, the film support substrate 21, and the substrate 1 together form a first cavity. The support housing 22 is disposed on the film support substrate 21 and is insulated from the film support substrate 21. At least a portion of the structure of the support housing 22 is located on the side of the diaphragm 31 away from the substrate 1 and is spaced apart from the diaphragm 31. The support housing 22 and the diaphragm 31 together form a second cavity. The second electrode 5 is disposed on the side of the support housing 22 facing the diaphragm 31 and is accommodated in the second cavity.

[0076] It should be noted that, in this embodiment, the second electrode 5 of the vibration sensor 100 is disposed in the second cavity formed by the support housing 22 and the diaphragm 31 to form a single-capacitor vibration sensor 100.

[0077] The present invention also provides an audio device, including a vibration sensor 100. The specific structure of the vibration sensor 100 is as described in the above embodiments. Since this audio device adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here. The audio device can be a smart headset, a smart speaker, a microphone, a recording device, or any electronic device that requires precise sensing of vibration or acoustic environment.

[0078] 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 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 vibration sensor, characterized in that, include: A substrate having a connecting surface; The support member is fixedly disposed on the connecting surface; A vibration assembly, comprising a diaphragm and a mass block; the diaphragm is suspended from the support member and, together with the substrate and / or the support member, forms at least one cavity; the mass block is attached to the diaphragm. A sensitive capacitor assembly includes a first electrode and at least one second electrode spaced apart; a mass block is configured as the first electrode; at least one second electrode is housed in the cavity; both the first electrode and the second electrode are electrically connected to the substrate. as well as A signal conditioning chip, wherein the signal conditioning chip is electrically connected to the substrate; The mass block can change the distance between the first electrode and the second electrode when the diaphragm vibrates; The support includes a membrane support substrate, one end of which is fixedly connected to the connecting surface, and the diaphragm is disposed at the end of the membrane support substrate away from the connecting surface. The diaphragm, the film support substrate, and the substrate together form a first cavity; The second electrode is disposed on the connecting surface and accommodated in the first cavity; The support member further includes a support housing, which is disposed on the membrane support substrate and is insulated from the membrane support substrate; at least a portion of the support housing is located on the side of the diaphragm away from the substrate and is spaced apart from the diaphragm; the support housing and the diaphragm together form a second cavity; The sensitive capacitor assembly includes two second electrodes. One second electrode is disposed on the connection surface and housed in the first cavity, and the other second electrode is disposed on the side of the support housing facing the diaphragm and housed in the second cavity.

2. The vibration sensor as described in claim 1, characterized in that, The signal conditioning chip is located on the side of the support housing facing away from the substrate, and the orthographic projection of the signal conditioning chip on the substrate and the orthographic projection of the diaphragm on the substrate overlap at least partially.

3. The vibration sensor as described in claim 1, characterized in that, The support housing is provided with an electrical connection layer, which is electrically connected to the second electrode and the substrate.

4. The vibration sensor as described in claim 1, characterized in that, The membrane support substrate is made of a conductive material, and the membrane support substrate is electrically connected to the substrate and the mass block.

5. The vibration sensor as described in claim 4, characterized in that, The film support substrate is a conductive ring, and one end face of the conductive ring is attached to the substrate; The vibration assembly also includes at least one second wire, which electrically connects the mass block and the membrane support substrate.

6. The vibration sensor as described in claim 1, characterized in that, The vibration sensor has a first ventilation channel that runs through the mass block and the diaphragm, and the first ventilation channel is connected to the first cavity.

7. The vibration sensor as described in any one of claims 1 to 6, characterized in that, The vibration sensor also includes a housing, which is connected to the connecting surface. The housing and the substrate together enclose a receiving space. The housing has an equalizing hole that communicates with the receiving space. The support, the sensitive capacitor assembly, and the signal conditioning chip are all housed within the receiving space.

8. An audio device, characterized in that, Including the vibration sensor as described in any one of claims 1 to 7.

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