Parallel shell structure MEMS bone conduction microphone

Abstract

The utility model discloses a parallel shell structure MEMS bone conduction microphone belongs to bone conduction microphone technical field. A parallel shell structure MEMS bone conduction microphone, including shell body and PCB, the shell body is installed at the top of PCB, wherein, both ends of PCB bottom are provided with PAD, the inside of shell body is provided with cavity board, and the cavity board is attached with PCB, and the top of cavity board is provided with inner shell. To solve the problem that the sound pressure of the diaphragm vibration of the existing vibrating membrane is easy to be affected by air and ultralow frequency to MEMS sensor, resulting in the overall sensitivity of the microphone is reduced, the parallel shell structure forms the firm and low-loss vibration transmission chain, ensures that the bone conduction vibration energy can be efficiently and faithfully transmitted to the core diaphragm and mass block assembly, the position and structure design of the inner sound hole and the outer sound hole realize the efficient coupling of the sound pressure of the diaphragm vibration to the MEMS sensor, maximize the utilization of vibration energy, improve the overall sensitivity of the microphone.

Description

Technical Field

[0001] This utility model relates to the field of bone conduction microphone technology, specifically a parallel shell structure MEMS bone conduction microphone. Background Technology

[0002] Bone conduction microphones transmit sound signals by picking up the vibrations of the speaker's own bones. They are widely used in the field of smart wearables. Currently, bone conduction MEMS microphones have a relatively complex structure and are difficult to package.

[0003] Meanwhile, the sound pressure generated by the existing diaphragm vibration is easily affected by air and ultra-low frequencies in MEMS sensors, resulting in a decrease in the overall sensitivity of the microphone. Utility Model Content

[0004] The purpose of this invention is to provide a parallel shell structure MEMS bone conduction microphone. The parallel shell structure forms a robust and low-loss vibration transmission chain, ensuring that bone conduction vibration energy can be efficiently and faithfully transmitted to the core diaphragm and mass block assembly. The position and structural design of the inner and outer sound holes realize efficient coupling of the sound pressure generated by the diaphragm vibration to the MEMS sensor, maximizing the utilization of vibration energy and improving the overall sensitivity of the microphone, thus solving the problems in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a parallel shell structure MEMS bone conduction microphone, including an outer shell and a PCB. The outer shell is mounted on top of the PCB. PADs are provided at both ends of the bottom of the PCB. A cavity plate is provided inside the outer shell and is attached to the PCB. An inner shell is provided above the cavity plate. A MEMS is provided on one side of the inner shell, and an ASIC is provided on one side of the MEMS.

[0006] Preferably, the MEMS and ASIC are connected by gold wires, and the ASIC is connected to the PCB by gold wires.

[0007] Preferably, the outer surface of the outer casing is provided with vent holes.

[0008] The above solution effectively prevents static pressure differences, ensuring that the MEMS and diaphragm operate at the designed bias point, and avoiding nonlinear distortion or sensitivity changes caused by pressure offset.

[0009] Preferably, a support ring is provided inside the inner shell, and a mass block is provided on the inner side of the support ring, wherein a diaphragm is provided above the mass block.

[0010] The addition of the mass block in the above scheme allows for precise tuning of the diaphragm's resonant frequency, optimizing the microphone's sensitivity and flatness in the target frequency band.

[0011] Preferably, an internal acoustic hole is provided between the support ring and the cavity plate.

[0012] Preferably, an external acoustic hole is provided between the MEMS and the cavity plate.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. In this utility model, the parallel shell structure forms a robust and low-loss vibration transmission chain, ensuring that bone conduction vibration energy can be efficiently and faithfully transmitted to the core diaphragm and mass block assembly. The position and structural design of the inner and outer sound holes realize the efficient coupling of the sound pressure generated by the diaphragm vibration to the MEMS sensor, maximizing the utilization of vibration energy and improving the overall sensitivity of the microphone.

[0015] 2. The present invention features a double-shell structure and a carefully designed sound hole path that effectively isolates the interference of ambient air noise. The vent hole is mainly used for air pressure balance and low-frequency filtering, rather than the main sound inlet, which further enhances the ability to pick up pure bone conduction speech in noisy environments and significantly improves the signal-to-noise ratio. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall internal structure of this utility model.

[0017] In the diagram: 1. Outer shell; 2. Inner shell; 3. PCB; 4. PAD; 5. MEMS; 6. ASIC; 7. Gold wire; 101. Cavity board; 102. External sound hole; 103. Internal sound hole; 104. Vent hole; 201. Diaphragm; 202. Mass block; 203. Support ring. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] To address the issue that existing diaphragm vibration-generated sound pressure levels in MEMS sensors are easily affected by air and ultra-low frequencies, leading to a decrease in the overall sensitivity of the microphone; please refer to... Figure 1 The present invention provides the following solution:

[0020] A parallel shell structure MEMS bone conduction microphone includes an outer shell 1 and a PCB 3. The outer shell 1 is mounted on top of the PCB 3. PAD 4 is provided at both ends of the bottom of the PCB 3. A cavity plate 101 is provided inside the outer shell 1. The cavity plate 101 is attached to the PCB 3. An inner shell 2 is provided above the cavity plate 101. A MEMS 5 is provided on one side of the inner shell 2. An ASIC 6 is provided on one side of the MEMS 5.

[0021] In this embodiment, when the sound source is conducted to the outer shell of the microphone through tissues such as bones and skin, the vibration energy acts on the entire microphone structure. The vibration energy is directly transmitted to the outer shell 1 that is in contact with the wearing surface. The vibration of the outer shell 1 is transmitted through its structure to the inner shell 2 structure that is closely fitted to it. The key components in the inner shell 2 are the diaphragm 201 and the mass block 202 coupled to it. The vibration energy transmitted to the inner shell 2 drives the diaphragm 201 to generate corresponding mechanical vibration. The mass block 202 is connected to the diaphragm 201, and its function is to optimize the vibration characteristics of the diaphragm 201 and provide the necessary inertia so that the diaphragm can more effectively follow the bone conduction vibration within a specific frequency range. The vibration of the diaphragm 201 changes the air pressure in the sealed cavity below it.

[0022] MEMS5 and ASIC6 are connected by gold wire 7, and ASIC6 is connected to PCB3 by gold wire 7. Vent holes 104 are provided on the outer surface of the outer shell 1. A support ring 203 is provided inside the inner shell 2. A mass block 202 is provided on the inner side of the support ring 203. A diaphragm 201 is provided above the mass block 202. An inner acoustic hole 103 is provided between the support ring 203 and the cavity plate 101. An outer acoustic hole 102 is provided between MEMS5 and the cavity plate 101.

[0023] In this embodiment, the inner acoustic hole 103 is located between the support ring 203 and the cavity plate 101, and is a key channel connecting the lower cavity of the diaphragm 201 and the front cavity where the MEMS5 sensor is located. The pressure fluctuations generated by the vibration of the diaphragm 201 are propagated out through the inner acoustic hole 103. The outer acoustic hole 102 is located between the MEMS5 and the cavity plate 101, and is a channel connecting the front cavity where the MEMS5 sensor is located to the outside world.

[0024] At the heart of the MEMS5 sensor is an extremely precise movable diaphragm. Pressure waves transmitted from the inner acoustic aperture 103 act on one side of the MEMS5 diaphragm, while pressure transmitted through the outer acoustic aperture 102 acts on the other side. The MEMS5 detects the dynamic pressure difference across the diaphragm caused by bone conduction vibration, and converts the detected pressure difference into a weak analog electrical signal in real time.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A parallel shell structure MEMS bone conduction microphone, characterized in that, The device includes an outer shell (1) and a PCB (3). The outer shell (1) is mounted on top of the PCB (3). PADs (4) are provided at both ends of the bottom of the PCB (3). A cavity plate (101) is provided inside the outer shell (1). The cavity plate (101) is attached to the PCB (3). An inner shell (2) is provided above the cavity plate (101). A MEMS (5) is provided on one side of the inner shell (2). An ASIC (6) is provided on one side of the MEMS (5).

2. The parallel shell structure MEMS bone conduction microphone according to claim 1, characterized in that: The MEMS (5) and ASIC (6) are connected by gold wire (7), and the ASIC (6) is connected to the PCB (3) by gold wire (7).

3. The parallel shell structure MEMS bone conduction microphone according to claim 1, characterized in that: The outer surface of the outer casing (1) is provided with a vent hole (104).

4. A parallel shell structure MEMS bone conduction microphone according to claim 1, characterized in that: The inner shell (2) is provided with a support ring (203) inside, and a mass block (202) is provided on the inner side of the support ring (203). A diaphragm (201) is provided above the mass block (202).

5. A parallel shell structure MEMS bone conduction microphone according to claim 4, characterized in that: An internal acoustic hole (103) is provided between the support ring (203) and the cavity plate (101).

6. A parallel shell structure MEMS bone conduction microphone according to claim 1, characterized in that: An external acoustic hole (102) is provided between the MEMS (5) and the cavity plate (101).

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