A directional microphone, diaphragm unit, and electronic device

Abstract

The embodiment of the application provides a directional microphone, a diaphragm unit and an electronic device, the directional microphone comprises: a diaphragm unit which is a bottomless box structure. Further comprising a microphone signal processing chip and a first PCB, the diaphragm unit and the plane where the contact surface of the first PCB is located jointly form a front cavity, the first PCB comprises at least one first PCB first opening, the at least one first PCB first opening is communicated with the front cavity, and the at least one first PCB first opening serves as a front cavity communication pipe. The bottom edge of the bottomless box part is fixedly connected to the first PCB, the bottomless box part and the plane where the contact surface of the first PCB is located jointly form a containing cavity, the containing cavity contains a rear cavity, and the rear cavity is connected with the rear cavity communication pipe formed by the opening. 0.5<=f2:f1<=1.25 is satisfied. By controlling the numerical range of f2:f1 to be close to 1:1, the resonance frequencies of the front cavity and the rear cavity as the two Helmholtz resonance cavities in front and behind the diaphragm are similar, so that the directivity of the directional microphone is improved.

Description

Technical Field

[0001] This application relates to the field of electronic device technology, and more particularly to a directional microphone, a diaphragm unit, and an electronic device. Background Technology

[0002] In recent years, with the rapid development and popularization of electronic devices, electronic devices with directional sound pickup functions, such as voice recorders and mobile phones, have long been integrated into all aspects of people's lives.

[0003] However, existing electronic devices with directional sound pickup capabilities often suffer from poor sound reception from specific directions due to the poor directionality of their internal directional microphones. Furthermore, the low sensitivity of directional microphones fails to meet the growing demands of users. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a directional microphone, diaphragm unit, and electronic device that can improve sound pickup sensitivity and effectively enhance the bandwidth of directional applications.

[0005] In a first aspect, embodiments of this application provide a directional microphone, comprising: a diaphragm unit, the diaphragm unit being a bottomless box structure, the top surface of the diaphragm unit including a diaphragm; a microphone signal processing chip, used to acquire electrical signals output by the diaphragm unit and process them to obtain microphone signals; and a first PCB, the bottom edge of the diaphragm unit being fixedly connected to the first PCB, the plane containing the contact surfaces of the diaphragm unit and the first PCB forming a front cavity, the first PCB including at least one first PCB first opening. At least one first PCB with a first opening connects to the front cavity, serving as the front cavity connecting pipe; a bottomless box component, the bottom edge of which is fixedly connected to the first PCB, the plane where the bottomless box component and the first PCB contact surface are located encloses to form an accommodating cavity, the accommodating cavity at least accommodates a diaphragm unit, and an air-filled rear cavity, the rear cavity being connected to the rear cavity connecting pipe formed by the opening; wherein, the resonant frequency f1 of the front cavity and the resonant frequency f2 of the rear cavity satisfy 0.5≤f2:f1≤1.25.

[0006] This application embodiment controls the numerical range of f1:f2 to around 1:1, so that the resonant frequencies of the two Helmholtz resonant cavities before and after the diaphragm of the front cavity and the rear cavity are similar, thereby improving the directivity of the directional microphone.

[0007] In some possible implementations, the bottomless housing component includes a shell comprising a top cover and sidewalls surrounding the top cover. The top cover includes at least one top cover opening serving as a connecting tube for the rear cavity. The rear cavity can be formed using the shell and a first PCB. The shell has the advantages of being easy to manufacture and having easily adjustable design dimensions.

[0008] In some possible implementations, the bottomless housing component includes a second PCB and a retaining wall, with the two side edges of the retaining wall connected to the first PCB and the second PCB, respectively. The second PCB includes at least one second PCB first opening, which serves as a connecting tube for the rear cavity. The second PCB may have other functional circuits. This design reduces the size of the directional microphone and improves the integration of the electronic device.

[0009] In some possible implementations, the projection of the front cavity connecting tube onto the height of the directional microphone lies within the projection of the rear cavity connecting tube onto the height of the directional microphone in a plane parallel to the length and width directions of the directional microphone. Therefore, it possesses corresponding acoustic characteristics and can adapt to the appropriate electronic device mounting space and opening positions.

[0010] In some possible implementations, in a plane parallel to the length and width directions of the directional microphone, the projection of the front cavity connecting tube onto the height direction of the directional microphone coincides with, is tangent to, or has a predetermined distance from the projection of the rear cavity connecting tube onto the height direction of the directional microphone. Therefore, it possesses corresponding acoustic characteristics and can adapt to the corresponding electronic device installation space and opening positions.

[0011] In some possible implementations, the first PCB further includes at least one first PCB second opening, which serves as the rear cavity connecting pipe. Therefore, it possesses corresponding acoustic characteristics and can adapt to the corresponding electronic device mounting space and opening location.

[0012] In some possible implementations, the ratio S2:S1≥2.5 is also included; where S1 is the cross-sectional area of ​​the front cavity connecting tube and S2 is the cross-sectional area of ​​the rear cavity connecting tube. By controlling the ratio of S2:S1, the numerical range of f1:f2 can be controlled to around 1:1, making the resonant frequencies of the two Helmholtz resonant cavities before and after the diaphragm of the front and rear cavities similar, thereby improving the directivity of the directional microphone.

[0013] Some possible implementations also include satisfying 3.5 ≤ V2:V1 ≤ 20; where V1 is the volume of the front cavity and V2 is the volume of the rear cavity. By controlling the ratio of V2:V1, the numerical range of f1:f2 can be controlled to around 1:1, making the resonant frequencies of the two Helmholtz resonators before and after the diaphragm similar, thereby improving the directivity of the directional microphone.

[0014] In some possible implementations, the bottomless housing component includes a top cover and side walls, with the thickness of the top cover being greater than the thickness of the side walls. By increasing the thickness of the top cover, the volume V2 of the rear cavity formed by the bottomless housing component and the first PCB is occupied, thereby adjusting the V2:V1 ratio and controlling the f1:f2 ratio to around 1:1. This makes the resonant frequencies of the two Helmholtz resonators before and after the diaphragm in the front and rear cavities similar, thus improving the directivity of the directional microphone.

[0015] In some possible implementations, the accommodating cavity also contains a filler material that occupies space within the cavity. By utilizing the filler material to occupy space within the cavity, the volume V2 of the rear cavity is reduced, thereby adjusting the V2:V1 ratio. By controlling the numerical range of f1:f2 to around 1:1, the resonant frequencies of the two Helmholtz resonators, acting as the diaphragm before and after the front and rear cavities, are similar, thus improving the directivity of the directional microphone.

[0016] In some possible implementations, the filler includes sound-absorbing cotton and / or dike adhesive.

[0017] In some possible implementations, a first occupier connection is also included. This first occupier connection is located between the bottom edge of the diaphragm unit and the first PCB, connecting the diaphragm unit and the first PCB. By utilizing the space occupied by the first occupier connection, the volume V2 of the rear cavity is reduced, and the volume V1 of the front cavity is increased, thereby adjusting the V2:V1 ratio. By controlling the value range of f1:f2 to around 1:1, the resonant frequencies of the front and rear cavities, which act as two Helmholtz resonant cavities before and after the diaphragm, are similar, thereby improving the directivity of the directional microphone.

[0018] In some possible implementations, the first spacer connection includes a gasket and / or adhesive.

[0019] In some possible implementations, a second occupier connection is also included. The microphone signal processing chip is located within the accommodating cavity, and the second occupier connection is positioned between the microphone signal processing chip and the first PCB, connecting the microphone signal processing chip and the first PCB. By utilizing the space occupied by the second occupier in the accommodating cavity, the volume V2 of the rear cavity is reduced, thereby adjusting the V2:V1 ratio. By controlling the value range of f1:f2 to around 1:1, the resonant frequencies of the two Helmholtz resonant cavities before and after the diaphragm in the front and rear cavities are similar, thereby improving the directivity of the directional microphone.

[0020] In some possible implementations, the second spacer connection includes a gasket and / or adhesive.

[0021] Among the possible implementations is one that satisfies 0.19 ≤ H. PCB :H a ≤0.538; where H PCB H is the thickness of the first PCB. a The height of the directional microphone is defined as follows. The length L1 of the front cavity connecting tube and / or the volume V2 of the rear cavity are adjusted by changing the thickness of the first PCB and / or the height of the bottomless box structure, thereby adjusting the V2:V1 ratio. The numerical range of f1:f2 is controlled to be around 1:1, so that the resonant frequencies of the two Helmholtz resonant cavities before and after the diaphragm in the front and rear cavities are similar, thus improving the directivity of the directional microphone.

[0022] In some possible implementations, the diaphragm unit further includes: a support, comprising a support body and a support through-hole, the support through-hole extending through the support body along the height direction of the diaphragm unit; a back electrode, the back electrode being a metal plate with a sound passage, the edge of the back electrode being connected to the sidewall of the support through-hole; the diaphragm includes a MEMS chip diaphragm, the MEMS chip diaphragm including a diaphragm body, multiple fixed comb-tooth diaphragms, a closed-shape diaphragm, multiple fixed support portions, and multiple movable comb-tooth diaphragms, the diaphragm body being fixedly connected to the top surface of the support body, the diaphragm body including an opening, and the multiple fixed comb-tooth diaphragms being fixedly connected... The fixed comb diaphragm is connected to the edge of the opening of the diaphragm body, and the fixed comb diaphragm and the diaphragm body are both at a first height. One end of the fixed support is connected to the edge of the opening of the diaphragm body, and the other end of the fixed support is connected to the edge of the closed-shape diaphragm. The movable comb diaphragm is connected to the edge of the closed-shape diaphragm, and the movable comb diaphragm and the closed-shape diaphragm are both at a second height. In the vertical projection formed by projecting along the height direction of the diaphragm unit, the projection of the movable comb diaphragm and the projection of the fixed comb diaphragm are alternately arranged; wherein, the first height is higher than the second height.

[0023] Because the moving comb diaphragm is sensitive to small airflows, while the closed-shape diaphragm is sensitive to sound pressure differences, a design that combines both can detect small airflows and sound pressure differences. The moving diaphragm, composed of the closed-shape and moving comb diaphragms, is connected to the stationary diaphragm body only by a fixed support; this design enhances the sensitivity of directional microphones.

[0024] In some possible implementations, the shape of the closed-shape diaphragm includes circular, elliptical, triangular, rectangular, or polygonal shapes.

[0025] In some possible implementations, the microphone signal processing chip acquires a first capacitance δC1 between the moving comb diaphragm and the fixed comb diaphragm, and a second capacitance δC2 between the closed-shape diaphragm and the back electrode, and outputs a differential output signal based on the first capacitance δC1 and the second capacitance δC2. By using differential output, the error signals of δC1 and δC2 can be eliminated through subtraction, thereby improving the signal-to-noise ratio of the directional microphone 40.

[0026] In some possible implementations, 0.8 ≤ f2: f1 ≤ 1.25 is satisfied.

[0027] In some possible implementations, the condition S2:S1≥2.75 is satisfied; where S1 is the cross-sectional area of ​​the front cavity connecting tube and S2 is the cross-sectional area of ​​the rear cavity connecting tube.

[0028] Secondly, embodiments of this application also provide a diaphragm unit, comprising: a bracket, including a bracket body and a bracket through hole, the bracket through hole penetrating the bracket body along the height direction of the diaphragm unit; a back electrode, the back electrode being a metal plate with a sound passage hole, the edge of the back electrode being connected to the sidewall of the bracket through hole; and a MEMS chip diaphragm, the MEMS chip diaphragm including a diaphragm body, multiple fixed comb-tooth diaphragms, a closed-shape diaphragm, multiple fixed support portions, and multiple movable comb-tooth diaphragms, the diaphragm body being fixedly connected to the top surface of the bracket body, the diaphragm body including an opening, and the multiple fixed comb-tooth diaphragms being fixedly connected to the bracket body. The opening edge of the diaphragm body, and the fixed comb diaphragm and the diaphragm body are both at a first height, one end of the fixed support is connected to the opening edge of the diaphragm body, the other end of the fixed support is connected to the edge of the closed-shape diaphragm, the movable comb diaphragm is connected to the edge of the closed-shape diaphragm, and the movable comb diaphragm and the closed-shape diaphragm are both at a second height, in the vertical projection formed by projecting along the height direction of the diaphragm unit, the projection of the movable comb diaphragm and the projection of the fixed comb diaphragm are alternately arranged; wherein, the first height is higher than the second height.

[0029] Because the moving comb diaphragm is sensitive to small airflows, while the closed-shape diaphragm is sensitive to sound pressure differences, a design that combines both can detect small airflows and sound pressure differences. The moving diaphragm, composed of the closed-shape and moving comb diaphragms, is connected to the stationary diaphragm body only by a fixed support; this design enhances the sensitivity of directional microphones.

[0030] In some possible implementations, the shape of the closed-shape diaphragm includes circular, elliptical, triangular, rectangular, or polygonal shapes.

[0031] Thirdly, this application embodiment also provides a directional microphone, including any of the aforementioned diaphragm units, and further including a microphone signal processing chip. The microphone signal processing chip acquires a first capacitance δC1 between the moving comb diaphragm and the fixed comb diaphragm, and a second capacitance δC2 between the closed-shape diaphragm and the back electrode, and outputs a differential output signal formed based on the first capacitance δC1 and the second capacitance δC2. By using differential output, the error signals of δC1 and δC2 can be eliminated by subtraction, thereby improving the signal-to-noise ratio of the directional microphone 40.

[0032] Fourthly, this application also provides an electronic device, including any of the above-described directional microphones, further comprising a first housing, a first multilayer board, a first sealing assembly, a microphone connecting plate, a second sealing assembly, a second multilayer board, and a second housing; the first housing, the first multilayer board, the first sealing assembly, the microphone connecting plate, the directional microphone, the second sealing assembly, the second multilayer board, and the second housing are sequentially connected; the first sealing assembly is used for sealing the acoustic channel of the front cavity connecting tube, the second sealing assembly is used for sealing the acoustic channel of the rear cavity connecting tube, and the microphone connecting plate is used to realize the electrical connection between the directional microphone and an external circuit; the first housing, the first multilayer board, the first sealing assembly, and the microphone connecting plate are all provided with through holes whose positions correspond to the positions of the front cavity connecting tube, and the second sealing assembly, the second multilayer board, and the second housing are all provided with through holes whose positions correspond to the positions of the rear cavity connecting tube. This provides beneficial effects corresponding to the above-described directional microphone.

[0033] Fifthly, embodiments of this application also provide an electronic device, including any of the aforementioned directional microphones, or including any of the aforementioned diaphragm units. This provides beneficial effects corresponding to the aforementioned directional microphones or diaphragm units. Attached Figure Description

[0034] Figure 1 A schematic diagram of the front structure of a mobile phone provided in an embodiment of this application;

[0035] Figure 2 A schematic diagram of the back structure of a mobile phone provided in an embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the structure of a directional microphone in related technologies;

[0037] Figure 4 For along Figure 3 Cross-sectional view of AA';

[0038] Figure 5 A schematic diagram of the structure of a directional microphone provided in this application;

[0039] Figure 6 The first embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0040] Figure 7 The second embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0041] Figure 8 The third embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0042] Figure 9 The fourth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0043] Figure 10 The fifth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0044] Figure 11 The sixth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0045] Figure 12 The seventh embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0046] Figure 13 The eighth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0047] Figure 14 The ninth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0048] Figure 15 The tenth embodiment of this application provides along Figure 5 Cross-sectional view of BB' formation;

[0049] Figure 16 A schematic diagram of the structure of an electronic device provided in this application;

[0050] Figure 17 For along Figure 16 Cross-sectional view of CC' formation;

[0051] Figure 18 A schematic diagram of the structure of a directional microphone (without housing shown) provided for this application;

[0052] Figure 19 This application provides a schematic diagram of the structure of a diaphragm unit;

[0053] Figure 20 A top view of a MEMS chip diaphragm provided in this application;

[0054] Figure 21 For along Figure 19 Cross-sectional view of DD' formation;

[0055] Figure 22 A partial structural schematic diagram of another MEMS chip diaphragm provided in this application;

[0056] Figure 23 A partial structural schematic diagram of another MEMS chip diaphragm provided in this application;

[0057] Figure 24 When sound is incident from the side closest to the diaphragm, it travels along... Figure 19 Cross-sectional view of DD' formation;

[0058] Figure 25 When sound is incident from the side closest to the dorsal pole, it travels along... Figure 19 Cross-sectional view of DD' formation;

[0059] Figure 26 This is a frequency-suppression ratio curve comparing the embodiments of this application with the prior art. Detailed Implementation

[0060] 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 some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0061] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0062] The terms "up," "down," "left," and "right," used in this document to indicate direction, are intended only to clearly explain the embodiments and describe one possible arrangement or layout of the components. They are not intended to limit the relationship between components or the orientation of the components.

[0063] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first target object" and "second target object," etc., are used to distinguish different target objects, not to describe a specific order of target objects.

[0064] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0065] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units means two or more processing units; multiple systems means two or more systems.

[0066] This application provides an electronic device, which may be a mobile phone, tablet computer, personal digital assistant (PDA), in-vehicle computer, smart wearable device, smart home device, etc. This application does not impose any special limitation on the specific form of the above-mentioned electronic device. Figure 1 This is a schematic diagram of the front structure of a mobile phone provided in an embodiment of this application. Figure 2 This is a schematic diagram of the back structure of a mobile phone provided in an embodiment of this application. See also... Figure 1 and Figure 2 For ease of explanation, we will use a mobile phone as an example.

[0067] like Figure 1 and Figure 2As shown, the mobile phone 100 includes a mid-frame 10, a back cover 20, and a display panel 30. The back cover 20 and the display panel 30 are positioned opposite each other, with the mid-frame 10 located between them. The mid-frame 10, the back cover 20, and the display panel 30 can form a receiving cavity. The receiving cavity houses a motherboard, a directional microphone, a battery, and a retaining wall (not shown) for securing the battery. The directional microphone can be mounted on the mid-frame 10. The motherboard houses a processor and a memory. The memory stores computer program code. The computer program code includes computer instructions. The processor invokes the computer instructions to cause the mobile phone 100 to perform corresponding operations.

[0068] The material of the back cover 20 may include, for example, opaque materials such as plastic, vegan leather, and fiberglass; or it may include translucent materials such as glass. This application does not limit the material of the back cover 20.

[0069] The display panel 30 includes, for example, a liquid crystal display (LCD) panel, an organic light-emitting diode (OLED) display panel, and an LED display panel, wherein the LED display panel includes, for example, a micro-LED display panel and a mini-LED display panel. This application embodiment does not limit the type of the display panel 30.

[0070] The following section describes the structure of a directional microphone.

[0071] A directional microphone works by detecting the sound pressure difference between the front and back of a diaphragm. When sound waves reach the diaphragm, the difference in their path causes different pressures on both sides, driving the diaphragm to vibrate. The diaphragm is then connected to an electromagnetic system, which converts the mechanical vibration into an electrical signal. Figure 3 This is a schematic diagram of the structure of a directional microphone in related technologies. Figure 4 For along Figure 3 See the cross-sectional diagram formed by AA'. Figure 3 and Figure 4As shown in the diagram above, the structure of a directional microphone can be divided into a diaphragm, a front cavity connecting tube, a front cavity body, a rear cavity connecting tube, and a rear cavity body. During sound pickup, sound can be incident at 0 degrees, meaning it enters the microphone directly through the front cavity connecting tube. Sound can also be incident at 180 degrees, meaning it enters directly through the rear cavity connecting tube. Other typical cases include sound incident at 90 degrees and 270 degrees. These two cases refer to external sound propagating towards the side walls of the microphone. Ideally, a directional microphone could completely receive sound incident at 0 degrees and 180 degrees, but would not receive sound incident at 90 degrees or 270 degrees. However, current directional microphones do not meet this requirement and are quite different from the ideal. The evaluation dimensions and indicators of directional microphones are mainly reflected in the following aspects. First, directivity. Directivity can be described by off-axis rejection ratio (OCR), measured in decibels (dB). It measures the difference in a microphone's ability to receive sound from different directions. For example, for a figure-eight directional microphone, its OCR can be expressed as the difference between the signal received from a sound wave incident at 0 degrees and the signal received from a sound wave incident at a side (90 degrees). Second, bandwidth. Bandwidth refers to the frequency range within which a certain OCR ratio can be maintained, measuring the effective operating frequency band of the device. Third, signal-to-noise ratio (SNR). SNR reflects the difference between the microphone's sensitivity and its noise floor, used to measure the device's sound pickup capability, measured in dB.

[0072] To enhance the directivity of a directional microphone, the inventors of this application discovered that resonance can be generated between the front and rear cavities, thereby improving the directivity of the microphone. Specifically, the front and rear cavities can be used as two Helmholtz resonant cavities before and after the diaphragm, coupled via diaphragm coupling. The resonant frequency f of the entire system can be approximately expressed by Equation 1, i.e.:

[0073]

[0074] Where f0 is the resonant frequency of the diaphragm, f1 is the resonant frequency of the front cavity, and f2 is the resonant frequency of the rear cavity. This formula shows that by designing a diaphragm with lower resonant frequencies, or by designing the structural parameters of a directional microphone to obtain lower f1 and f2, the overall resonant frequency of the microphone can be reduced, thereby improving the microphone's signal-to-noise ratio.

[0075] The formula for calculating f1 is Equation 2, namely:

[0076]

[0077] The formula for calculating f2 is Equation 3, namely:

[0078]

[0079] Where d1 is the cross-sectional diameter of the anterior cavity connecting tube, d2 is the cross-sectional diameter of the posterior cavity connecting tube, V1 is the volume of the anterior cavity, V2 is the volume of the posterior cavity, L1 is the length of the anterior cavity connecting tube, and L2 is the length of the posterior cavity connecting tube.

[0080] To achieve resonance between the front and rear cavities, f1 and f2 can be made approximately equal, thereby improving the directional performance of the directional microphone near the resonant frequency and enhancing its high-frequency directional effect. Alternatively, adjusting the structural parameters of the directional microphone can lower the overall resonant frequency, shifting the resonance peak to a lower frequency range, which can improve the microphone's signal-to-noise ratio and overall sensitivity. For example, the ratio of f2 to f1 can be constrained within the range of 0.5-1.25 to ensure good resonance between the front and rear cavities. Alternatively, the ratio of f2 to f1 can also be constrained within the range of 0.5-1.25 to ensure excellent resonance between the front and rear cavities.

[0081] In order to make f1 and f2 approach equal and obtain a better resonance effect, this application provides the following exemplary embodiments. Figure 5 A schematic diagram of a directional microphone provided in this application is shown below. Figure 5 For ease of description, we define the microphone's length as the X-axis, width as the Y-axis, and height as the Z-axis.

[0082] The following embodiments adjust the ratio between f1 and f2 by adjusting the ratio of the cross-sectional area S1 of the front connecting tube to the cross-sectional area S2 of the rear connecting tube. This allows S2:S1 ≥ 2.5. Optionally, the ratio of S2 to S1 can be limited to S2:S1 ≥ 2.75, thereby ensuring that the ratio between f1 and f2 approaches 1:1.

[0083] Example 1

[0084] Figure 6 The first embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 6The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube with a cross-sectional area of ​​S2. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming a receiving cavity with the first PCB 41. The receiving cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 is a bottomless box structure. The top surface of the diaphragm unit 43 is the diaphragm, and the sidewalls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the connection between the first PCB 41 and the second cavity. The first PCB first opening 412 serves as the front cavity connecting pipe, and its cross-sectional area is S1. In a plane parallel to the X and Y axes, the projection of the first PCB first opening 412 in the Z-axis direction lies within the projection of the top cover opening 4212 in the Z-axis direction. In other words, the front cavity connecting pipe and the rear cavity connecting pipe are arranged opposite each other.

[0085] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0086] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0087] Example 2

[0088] Figure 7 The second embodiment of this application provides along Figure 5 See the cross-sectional view of BB'. Figure 7 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube with a cross-sectional area of ​​S2. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming an accommodating cavity with the first PCB 41. The accommodating cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the side walls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the connection between the first PCB 41 and the second cavity. The first PCB first opening 412 serves as the front cavity connecting pipe, and its cross-sectional area is S1. In a plane parallel to the X and Y axes, the projection of the first PCB first opening 412 in the Z-axis direction coincides with, is tangent to, or has a preset distance from the projection of the top cover opening 4212 in the Z-axis direction. The preset distance can be determined according to actual needs. In other words, the front cavity connecting pipe and the rear cavity connecting pipe are offset.

[0089] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0090] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0091] Example 3

[0092] Figure 8 The third embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 8 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and multiple top cover openings 4212, which serve as rear cavity connecting pipes with a total cross-sectional area S2. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming a receiving cavity with the first PCB 41. The receiving cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 is a bottomless box structure. The top surface of the diaphragm unit 43 is the diaphragm, and the sidewalls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), so that a second cavity is formed between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the position where the first PCB 41 connects to the second cavity. The first PCB first opening 412 serves as the front cavity connecting pipe, and its cross-sectional area is S1. In a plane parallel to the X and Y axes, the projection of the first PCB first opening 412 in the Z-axis direction is located within the projection of the top cover opening 4212 in the Z-axis direction. In other words, the front cavity connecting pipe and the rear cavity connecting pipe are arranged opposite each other.

[0093] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0094] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0095] Example 4

[0096] Figure 9 The fourth embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 9 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and multiple top cover openings 4212, which serve as rear cavity connecting tubes with a cross-sectional area of ​​S2. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming a receiving cavity with the first PCB 41. The receiving cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 is a bottomless box structure. The top surface of the diaphragm unit 43 is the diaphragm, and the sidewalls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), so that a second cavity is formed between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the position where the first PCB 41 connects to the second cavity. The first PCB first opening 412 serves as the front cavity connecting tube, and its cross-sectional area is S1. In a plane parallel to the X and Y axes, the projection of the first PCB first opening 412 in the Z-axis direction coincides with, is tangent to, or has a preset distance from the projection of the top cover opening 4212 in the Z-axis direction. The preset distance can be determined according to actual needs. In other words, the anterior cavity connecting tube and the posterior cavity connecting tube are misaligned.

[0097] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0098] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0099] Example 5

[0100] Figure 10 The fifth embodiment of this application provides along Figure 5 See the cross-sectional view of BB'. Figure 10The directional microphone 40 includes a first printed circuit board (PCB) 41, a second PCB 45, a barrier 46, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The second PCB 45 can be a PCB specifically for the directional microphone 40, or it can be a PCB for other functional circuits. The barrier 46 is located between the first PCB 41 and the second PCB 45. The two side edges of the barrier 46 are connected to the first PCB 41 and the second PCB 45 respectively, forming a cavity. The cavity contains the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The second PCB 45 includes a second PCB body 451 and a second PCB first opening 452, which serves as a connecting tube for the rear cavity, with a cross-sectional area of ​​S2. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the sidewalls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. This second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, located at the position where the first PCB 41 connects to the second cavity. The first PCB first opening 412 serves as the front cavity connecting pipe, with a cross-sectional area of ​​S1. In a plane parallel to the X and Y axes, the projection of the first PCB first opening 412 in the Z-axis direction lies within the projection of the top cover opening 4212 in the Z-axis direction. In other words, the front cavity connecting pipe and the rear cavity connecting pipe are arranged opposite each other.

[0101] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0102] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0103] Example 6

[0104] Figure 11The sixth embodiment of this application provides along Figure 5 See the cross-sectional view of BB'. Figure 11 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming a receiving cavity with the first PCB 41. The receiving cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the side walls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411, a first PCB first opening 412, and a first PCB second opening 413. The first PCB first opening 412 is located at the position where the first PCB 41 connects to the second cavity, and the first PCB second opening 413 is located at the position where the first PCB 41 connects to the first cavity. The first PCB first opening 412 serves as the front cavity connecting tube, with a cross-sectional area of ​​S1. The first PCB second opening 413 serves as the rear cavity connecting tube, with a cross-sectional area of ​​S2.

[0105] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0106] This embodiment can constrain the ratio of f1 to f2 to around 1, or within the required range, by designing the ratio of S2 to S1.

[0107] The above embodiments describe several design methods for the cavity structure of the directional microphone 40, including cases where the rear cavity connecting tube is a single hole and cases where the rear cavity connecting tube is multi-hole. It should be understood that in the embodiments described herein, not only can the number of holes in the rear cavity connecting tube be determined according to actual needs, but the front cavity connecting tube can also be set to a single hole or multiple holes according to actual needs. Furthermore, whether the component opposite to the first PCB 41 is the housing 42 or the second PCB 45 can be determined according to actual needs. Additionally, whether the rear cavity connecting tube is located on the first PCB 41, or on the housing 42 or the second PCB 45 opposite to the first PCB 41, can also be determined according to actual needs. Moreover, whether the front cavity connecting tube and the rear cavity connecting tube are arranged opposite each other or staggered can also be determined according to actual needs. Furthermore, the location of the rear cavity connecting tube can also be the side wall 422 of the housing 42, or the baffle 46. The rear cavity connecting pipe can be formed by opening a through hole in the side wall 422 or the baffle 46, or it can be a notch formed by the side wall 422 partially surrounding the top cover, or the first end and the second end of the baffle 46 are not in contact along the length direction, but there is a gap between the first end and the second end, with the gap serving as the rear cavity connecting pipe. In other words, without affecting the function of the technical features in the embodiments, any feature in any embodiment of this application can be combined with each other to obtain new embodiments.

[0108] The following embodiments adjust the proportional relationship between f1 and f2 by adjusting the ratio of the volume V1 of the front cavity to the volume V2 of the rear cavity. In order to make f1 and f2 approach each other, the ratio of V2 to V1 can be set to a range of 3.5-20.

[0109] Example 7

[0110] Figure 12 The seventh embodiment of this application provides along Figure 5 See the cross-sectional view of BB'. Figure 12The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming an accommodating cavity with the first PCB 41. The accommodating cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the side walls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the connection between the first PCB 41 and the second cavity. The first PCB first opening 412 serves as the front cavity connecting pipe. In this embodiment, the top cover body 4211 is thickened, but its external dimensions remain consistent with the original directional microphone 40. This reduces the volume V2 of the rear cavity without requiring redesign of other component dimensions for the directional microphone 40.

[0111] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0112] This embodiment can constrain the ratio of V2 to V1 to the range of 3.5-20 by designing the ratio range of V2 to V1.

[0113] Alternatively, the top cover 421 can be replaced with the second PCB 45 and the retaining wall 46. By thickening the second PCB 45, the space occupied by the first cavity can be occupied, thereby adjusting the ratio range of V2 to V1. This will not be elaborated further in this article.

[0114] Example 8

[0115] Figure 13 The eighth embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 13 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming an accommodating cavity with the first PCB 41. The accommodating cavity contains the diaphragm unit 43, the ASIC chip 44, filler 46, and a first air cavity, which serves as the rear cavity. The filler may include materials such as sound-absorbing cotton or damming adhesive. The diaphragm unit 43 has a bottomless box structure. The top surface of the diaphragm unit 43 is the diaphragm, and the sidewalls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), so that a second cavity is formed between the diaphragm unit 43 and the first surface of the first PCB 41. The second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the position where the first PCB 41 connects to the second cavity. The first PCB first opening 412 serves as the front cavity connecting tube.

[0116] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0117] In this embodiment, the space occupied by the filling material is reduced, thereby reducing the size of the first cavity and the volume of the cavity, thus constraining the ratio of V2 to V1 to the range of 3.5-20.

[0118] Example 9

[0119] Figure 14 The ninth embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 14 The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, an application-specific integrated circuit (ASIC) chip 44, a first spacer connection 47, and a second spacer connection 48. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the side walls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 via the first spacer connection part 47, so that the diaphragm unit 43, the first spacer connection part 47, and the first surface of the first PCB 41 together form a second cavity, which serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41 via the second spacer connection part 48. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, which is located at the position where the first PCB 41 connects to the second cavity. The first PCB first opening 412 serves as a front cavity connecting tube. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming an accommodating cavity with the first PCB 41. The accommodating cavity houses the diaphragm unit 43, the first spacer connection portion 47 connecting the diaphragm unit 43 and the first surface of the first PCB 41, the ASIC chip 44, the second spacer connection portion 48 connecting the ASIC chip 44 and the first surface of the first PCB 41, and a first air cavity, which serves as the rear cavity. The first spacer connection portion 47 and the second spacer connection portion 48 can be gaskets or adhesives, occupying more space and reducing the volume of the first cavity through their spacer function.

[0120] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0121] In this embodiment, the first space-occupying connecting part 47 and the second space-occupying connecting part 48 occupy more space, reduce the volume of the first cavity, and reduce the volume of the rear cavity, thereby constraining the ratio of V2 to V1 to the range of 3.5-20.

[0122] The following embodiments adjust the thickness H of the first PCB41 PCB 40 H of directional microphone a The ratio of f1 to f2 can be used to adjust the proportional relationship between them. To make f1 and f2 approach each other, H can be set... PCB :H a The ratio ranges from 25% to 53.8%. Optionally, H can also be set. PCB :H a The ratio ranges from 19% to 53.8%.

[0123] Example 10

[0124] Figure 15 The tenth embodiment of this application provides along Figure 5 See the cross-sectional diagram of BB'. Figure 15The directional microphone 40 includes a first printed circuit board (PCB) 41, a housing 42, a diaphragm unit 43, and an application-specific integrated circuit (ASIC) chip 44. The housing 42 includes a top cover 421 and side walls 422, with the side walls 422 surrounding the top cover to form a bottomless box structure. The top cover 421 includes a top cover body 4211 and a top cover opening 4212, which serves as a rear cavity connecting tube. The material of the housing 42 can be selected according to actual needs, for example, it can be made of metal. The edge of the housing 42 is connected to the first surface of the first PCB 41, thereby forming an accommodating cavity with the first PCB 41. The accommodating cavity houses the diaphragm unit 43, the ASIC chip 44, and a first air cavity, which serves as the rear cavity. The diaphragm unit 43 has a bottomless box structure; the top surface of the diaphragm unit 43 is the diaphragm, and the side walls of the diaphragm unit 43 are the diaphragm unit body. The bottom edge of the diaphragm unit 43 is fixedly connected to the first surface of the first PCB 41 by a gasket or adhesive (not shown in the figure), forming a second cavity between the diaphragm unit 43 and the first surface of the first PCB 41. This second cavity serves as the front cavity. The ASIC chip 44 is fixedly connected to the first surface of the first PCB 41. The first PCB 41 includes a first PCB body 411 and a first PCB first opening 412, located at the connection point between the first PCB 41 and the second cavity. The first PCB first opening 412 serves as a connecting tube for the front cavity. This embodiment of the invention requires control of the height H of the directional microphone 40. a With the thickness H of the first PCB41 PCB The ratio range is 25%-53.8%, or 19%-53.8%. This can be achieved, for example, by reducing the height of the housing 42, thus reducing V2 to adjust the ratio range of V2 to V1. It can also be achieved by increasing the thickness H of the first PCB 41. PCB This is achieved by increasing the thickness H of the first PCB41. PCB This increases the length L1 of the front cavity connecting tube, thereby changing the L1:L2 ratio and making f1 and f2 closer together. Furthermore, the thickness H of the first PCB 41 can be increased while reducing the height of the housing 42. PCB This causes f1 and f2 to converge.

[0125] The diaphragm unit 43 is used to pick up sound wave vibrations, convert the mechanical signal of the sound wave vibration into an electrical signal, and transmit the electrical signal to the ASIC chip 44 through the flying wire between the diaphragm unit 43 and the ASIC chip 44. The ASIC chip 44 is used to analyze the electrical signal output by the diaphragm unit, and transmit the microphone signal output by the ASIC chip 44 to the first PCB 41 for further transmission through the flying wire between the ASIC chip 44 and the first PCB 41.

[0126] The embodiments of the present invention use H PCB :H a The ratio range is adjusted to 25%-53.8% or 19%-53.8% to make f1 and f2 approach each other.

[0127] The above embodiments provide a scheme for processing the signals of the diaphragm unit 43 using an ASIC chip 44. However, in addition to the ASIC chip 44, any microphone signal processing chip can be used. This embodiment of the invention does not limit the specific type of microphone signal processing chip.

[0128] The directional microphone 40 described above can be applied not only to the mobile phone 100, but also to any electronic device that requires directional sound pickup functionality. An exemplary assembly diagram of a directional microphone 40 applied to an electronic device will be given below. Figure 16 This is a schematic diagram of the structure of an electronic device provided in this application. Figure 17 For along Figure 16 See the cross-sectional view of CC'. Figure 16 and Figure 17The electronic device 200 includes a first housing 210, a first multilayer board 220, a first sealing assembly 230, a microphone connection board 240, a directional microphone 40, a second sealing assembly 250, a second multilayer board 260, and a second housing 270 arranged sequentially. The first multilayer board 220 and the second multilayer board 260 may be circuit boards that implement other functions of the electronic device 200. The first sealing assembly 230 is used to seal the acoustic channel of the front cavity connecting tube of the directional microphone 40, and the second sealing assembly 250 is used to seal the acoustic channel of the rear cavity connecting tube of the directional microphone 40. The microphone connection board 240 may be a PCB or a flexible printed circuit (FPC), and can be electrically connected to the first PCB 41 of the directional microphone 40 to connect the directional microphone 40 to external circuitry. The first outer shell 210, the first multilayer board 220, the first sealing component 230, the microphone connecting plate 240, the second sealing component 250, the second multilayer board 260, and the second outer shell 270 all have openings. The openings in the first outer shell 210, the first multilayer board 220, the first sealing component 230, and the microphone connecting plate 240 correspond to the positions of the front cavity connecting tube of the directional microphone 40. The openings in the second sealing component 250, the second multilayer board 260, and the second outer shell 270 correspond to the positions of the rear cavity connecting tube of the directional microphone 40. A mesh fabric is provided at the openings of the first sealing component 230 and the second sealing component 250, covering the openings of both components. The material of the mesh fabric can be determined according to actual needs, for example, it can be plastic or metal.

[0129] It should be noted that in some other embodiments, the first multilayer board 220 and the second multilayer board 250 may be omitted.

[0130] On the other hand, the present invention also provides a diaphragm unit 43, which can be applied to any type of directional microphone 40, including the embodiments described above. Figure 18 This application provides a structural schematic diagram of a directional microphone (without a housing shown). Figure 19 This is a schematic diagram of the structure of a diaphragm unit provided in this application. Figure 20 This is a top view of a MEMS chip diaphragm provided in this application. Figure 21 For along Figure 19 See the cross-sectional view of DD'. Figures 18-21The directional microphone 40 includes a diaphragm unit 43 and an ASIC chip 44. The diaphragm unit 43 includes a bracket 431, a back electrode 432, and a micro-electro-mechanical systems (MEMS) chip diaphragm 433. The bracket 431 includes a bracket body 4311 and a bracket through-hole 4312. The through-hole 4312 is open along the height direction of the diaphragm unit 43, and the back electrode 432 is disposed within the through-hole 4312. The back electrode 432 is a metal plate with a sound passage. The MEMS chip diaphragm 433 includes a diaphragm body 4331, multiple fixed comb-tooth diaphragms 4332, a closed-shape diaphragm 4333, multiple fixed support portions 4334, and multiple movable comb-tooth diaphragms 4335. The diaphragm body 4331 is fixedly connected to the top surface of the bracket body 4311 for fixing the MEMS chip diaphragm 433. The diaphragm body 4331 includes an opening, and multiple fixed comb-tooth diaphragms 4332 are fixedly connected to the edge of the opening in the diaphragm body 4331, with the surfaces of the fixed comb-tooth diaphragms 4332 and the surface of the diaphragm body 4331 located on the same plane. In other words, the fixed comb-tooth diaphragms 4332 and the diaphragm body 4331 are at the same height and are both located on a plane parallel to the length and width directions of the diaphragm unit 43. One end of the fixed support 4334 is connected to the edge of the opening in the diaphragm body 4331, and the other end is connected to the edge of the closed-shape diaphragm 4333. The closed-shape diaphragm 4333 is movably connected to the diaphragm body 4331 through the multiple fixed support 4334. The placement of the multiple fixed support 4334 can be determined according to actual needs and can be distributed around the periphery of the closed-shape diaphragm 4333. The height of the closed-shape diaphragm 4333 is lower than the height of the diaphragm body 4331. The movable comb-tooth diaphragm 4335 is connected to the edge of the closed-shape diaphragm 4333. In the vertical projection formed by projecting along the height direction of the diaphragm unit 43, the projection of the movable comb-tooth diaphragm 4335 and the projection of the fixed comb-tooth diaphragm 4332 alternate. There may be a gap between the projection of the movable comb-tooth diaphragm 4335 and the projection of the fixed comb-tooth diaphragm 4332, and there may also be a gap between the projection of the fixed support 4334 and the projection of the fixed comb-tooth diaphragm 4332. The height of the movable comb-tooth diaphragm 4335 is lower than the height of the fixed comb-tooth diaphragm 4332.

[0131] Figure 22 This is a partial structural schematic diagram of another MEMS chip diaphragm provided in this application. Figure 23 For a partial structural schematic diagram of another MEMS chip diaphragm provided in this application, see [link to schematic diagram]. Figure 22 and Figure 23 The shape of the closed-shape diaphragm 4333 can be not only circular, but also elliptical, triangular, rectangular, polygonal, or other closed shapes. This application embodiment does not limit the specific shape of the closed-shape diaphragm 4333.

[0132] The ASIC chip 44 acquires the first capacitance δC1 between the moving comb diaphragm 4335 and the fixed comb diaphragm 4332, and the second capacitance δC2 between the closed-shape diaphragm 4333 and the back electrode 432. By measuring the changes in the first capacitance δC1 and the second capacitance δC2, the vibration of the sound waves near the diaphragm unit 43 can be determined. Figure 24 When sound is incident from the side closest to the diaphragm, it travels along... Figure 19 See the cross-sectional view of DD'. Figure 24 The dashed box in the diagram represents the initial positions of the moving comb diaphragm 4335 and the closed-shape diaphragm 4333. When sound is incident from the direction closest to the diaphragm, the moving comb diaphragm 4335 moves downward, increasing the distance between the moving comb diaphragm 4335 and the fixed comb diaphragm 4332, thus decreasing the first capacitance δC1. Simultaneously, the distance between the closed-shape diaphragm 4333 and the back electrode 432 decreases, increasing the second capacitance δC2. The ASIC chip 44 uses differential output, and the total change in capacitance is calculated as δC2 - (-δC1). Figure 25 When sound is incident from the side closest to the dorsal pole, it travels along... Figure 19 See the cross-sectional view of DD'. Figure 25 The dashed box in the diagram represents the initial positions of the moving comb diaphragm 4335 and the closed-shape diaphragm 4333. When sound is incident from the direction closest to the back electrode 432, the moving comb diaphragm 4335 moves upward, the distance between the moving comb diaphragm 4335 and the fixed comb diaphragm 4332 decreases, and the first capacitance δC1 increases. Simultaneously, the distance between the closed-shape diaphragm 4333 and the back electrode 432 increases, and the second capacitance δC2 decreases. The ASIC chip 44 uses differential output, calculating the total capacitance change as δC1 - (-δC2). By using differential output, the error signals of δC1 and δC2 can be eliminated through subtraction, improving the signal-to-noise ratio of the directional microphone 40. Since the moving comb diaphragm 4335 is sensitive to small airflows, while the closed-shape diaphragm 4333 is sensitive to sound pressure differences, having both the moving comb diaphragm 4335 and the closed-shape diaphragm 4333 allows for the detection of both small airflows and sound pressure differences. The movable diaphragm, consisting of a closed-shape diaphragm 4333 and a movable comb diaphragm 4335, is connected to the fixed diaphragm body 4331 only by a fixed support part 4334. This design can improve the sensitivity of the directional microphone 40.

[0133] Figure 26 For a frequency-suppression ratio graph comparing the embodiments of this application with the prior art, see [link / reference]. Figure 26The diaphragm resonant frequency f0 of the aforementioned diaphragm unit 43 is within the range of 0.8-1.2. Compared to the prior art, the 1kHz suppression ratio is improved from 16dB to 21dB, and the bandwidth satisfied by the 10dB suppression ratio is improved from 200-2kHz to 200-10kHz. Since the maximum voice bandwidth requirement is typically 8kHz, it is evident that the embodiments of the present invention can effectively improve the bandwidth for directional applications and enhance voice pickup quality.

[0134] The above embodiments provide a scheme for processing the signals of the diaphragm unit 43 using an ASIC chip 44. However, in addition to the ASIC chip 44, any microphone signal processing chip can be used. This embodiment of the invention does not limit the specific type of microphone signal processing chip.

[0135] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many variations under the guidance of this application without departing from the spirit and scope of the claims. Those skilled in the art will understand that this invention is not limited to the specific embodiments described herein. Various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of this invention, and all such changes and substitutions are within the scope of protection of this application.

Claims

1. A directional microphone, characterized in that, include: A diaphragm unit, wherein the diaphragm unit is a box structure without a bottom surface, and the top surface of the diaphragm unit includes a diaphragm; A microphone signal processing chip is used to acquire the electrical signal output by the diaphragm unit and process the electrical signal output by the diaphragm unit to obtain a microphone signal. The first PCB has the bottom edge of the diaphragm unit fixedly connected to it. The plane where the diaphragm unit and the first PCB are in contact forms a front cavity. The first PCB includes at least one first PCB first opening, which communicates with the front cavity and serves as the front cavity communication tube. A bottomless box component, the bottom edge of which is fixedly connected to the first PCB, the plane where the bottomless box component and the first PCB are in contact forms an accommodating cavity, the accommodating cavity at least accommodates a diaphragm unit and an air-filled rear cavity, the rear cavity being connected to a rear cavity connecting tube formed by an opening; The resonant frequency f1 of the front cavity and the resonant frequency f2 of the rear cavity satisfy 0.5≤f2:f1≤1.

25.

2. The directional microphone according to claim 1, characterized in that, The bottomless box component includes a housing, which includes a top cover and side walls. The side walls are arranged around the top cover, and the top cover includes at least one top cover opening, which serves as a connecting pipe for the rear cavity.

3. The directional microphone according to claim 1, characterized in that, The bottomless box component includes a second PCB and a retaining wall. The two sides of the retaining wall are connected to the first PCB and the second PCB respectively. The second PCB includes at least one second PCB first opening, which serves as the rear cavity connecting pipe.

4. The directional microphone according to claim 2 or 3, characterized in that, In a plane parallel to the length and width directions of the directional microphone, the projection of the front cavity connecting tube in the height direction of the directional microphone lies within the projection of the rear cavity connecting tube in the height direction of the directional microphone.

5. The directional microphone according to claim 2 or 3, characterized in that, In a plane parallel to the length and width directions of the directional microphone, the projection of the front cavity connecting tube onto the height direction of the directional microphone coincides with, is tangent to, or has a preset distance from the projection of the rear cavity connecting tube onto the height direction of the directional microphone.

6. The directional microphone according to claim 1, characterized in that, The first PCB also includes at least one first PCB second opening, which serves as the rear cavity connecting pipe.

7. The directional microphone according to claim 1, characterized in that, This also includes satisfying S2:S1≥2.5; Wherein, S1 is the cross-sectional area of ​​the front cavity connecting tube, and S2 is the cross-sectional area of ​​the rear cavity connecting tube.

8. The directional microphone according to claim 1, characterized in that, This also includes conditions that satisfy 3.5≤V2:V1≤20; Wherein, V1 is the volume of the front cavity and V2 is the volume of the rear cavity.

9. The directional microphone according to claim 1, characterized in that, The bottomless box component includes a top cover and side walls, wherein the thickness of the top cover is greater than the thickness of the side walls.

10. The directional microphone according to claim 1, characterized in that, The cavity also contains a filler material, which occupies the space of the cavity.

11. The directional microphone according to claim 10, characterized in that, The filler includes sound-absorbing cotton and / or dike adhesive.

12. The directional microphone according to claim 1, characterized in that, It also includes a first spacer connection portion, which is located between the bottom edge of the diaphragm unit and the first PCB, connecting the diaphragm unit and the first PCB.

13. The directional microphone according to claim 12, characterized in that, The first spacer connection includes a gasket and / or adhesive.

14. The directional microphone according to claim 1, characterized in that, It also includes a second occupier connection part, wherein the microphone signal processing chip is located within the accommodating cavity, and the second occupier connection part is located between the microphone signal processing chip and the first PCB, connecting the microphone signal processing chip and the first PCB.

15. The directional microphone according to claim 14, characterized in that, The second spacer connection includes a gasket and / or adhesive.

16. The directional microphone according to claim 1, characterized in that, It also includes satisfying 0.19≤H PCB :H a ≤0.538; Among them, H PCB H is the thickness of the first PCB. a The height of the directional microphone.

17. The directional microphone according to claim 1, characterized in that, The diaphragm unit further includes: The bracket includes a bracket body and a bracket through hole, wherein the bracket through hole extends through the bracket body along the height direction of the diaphragm unit; A back electrode, wherein the back electrode is a metal plate with a sound passage hole, and the edge of the back electrode is connected to the side wall of the through hole of the bracket; The diaphragm includes a MEMS chip diaphragm, which comprises a diaphragm body, multiple fixed comb-tooth diaphragms, a closed-shape diaphragm, multiple fixed support portions, and multiple movable comb-tooth diaphragms. The diaphragm body is fixedly connected to the top surface of the support body. The diaphragm body includes an opening. Multiple fixed comb-tooth diaphragms are fixedly connected to the edge of the opening in the diaphragm body, and the fixed comb-tooth diaphragms and the diaphragm body are both at a first height. One end of the fixed support portion is connected to the edge of the opening in the diaphragm body, and the other end of the fixed support portion is connected to the edge of the closed-shape diaphragm. The movable comb-tooth diaphragms are connected to the edge of the closed-shape diaphragm, and the movable comb-tooth diaphragms and the closed-shape diaphragm are both at a second height. In the vertical projection formed by projecting along the height direction of the diaphragm unit, the projections of the movable comb-tooth diaphragms and the fixed comb-tooth diaphragms are alternately arranged. The first height is higher than the second height.

18. The directional microphone according to claim 17, characterized in that, The shape of the closed-shape diaphragm includes circular, elliptical, triangular, rectangular, or polygonal shapes.

19. The directional microphone according to claim 17, characterized in that, The microphone signal processing chip acquires the first capacitance δC1 between the moving comb diaphragm and the fixed comb diaphragm, and the second capacitance δC2 between the closed-shape diaphragm and the back electrode, and outputs a differential output signal based on the first capacitance δC1 and the second capacitance δC2.

20. The directional microphone according to claim 1, characterized in that, It satisfies 0.8≤f2:f1≤1.

25.

21. The directional microphone according to claim 1, characterized in that, The condition S2:S1≥2.75 is satisfied. Wherein, S1 is the cross-sectional area of ​​the front cavity connecting tube, and S2 is the cross-sectional area of ​​the rear cavity connecting tube.

22. A diaphragm unit, characterized in that, include: The bracket includes a bracket body and a bracket through hole, wherein the bracket through hole extends through the bracket body along the height direction of the diaphragm unit; A back electrode, wherein the back electrode is a metal plate with a sound passage hole, and the edge of the back electrode is connected to the side wall of the through hole of the bracket; The MEMS chip diaphragm includes a diaphragm body, multiple fixed comb-tooth diaphragms, a closed-shape diaphragm, multiple fixed support portions, and multiple movable comb-tooth diaphragms. The diaphragm body is fixedly connected to the top surface of the support body. The diaphragm body includes an opening. The multiple fixed comb-tooth diaphragms are fixedly connected to the edge of the opening of the diaphragm body, and the fixed comb-tooth diaphragms and the diaphragm body are at a first height. One end of the fixed support portion is connected to the edge of the opening of the diaphragm body, and the other end of the fixed support portion is connected to the edge of the closed-shape diaphragm. The movable comb-tooth diaphragms are connected to the edge of the closed-shape diaphragm, and the movable comb-tooth diaphragms and the closed-shape diaphragm are at a second height. In the vertical projection formed by projecting along the height direction of the diaphragm unit, the projections of the movable comb-tooth diaphragms and the fixed comb-tooth diaphragms are alternately arranged. The first height is higher than the second height.

23. The diaphragm unit according to claim 22, characterized in that, The shape of the closed-shape diaphragm includes circular, elliptical, triangular, rectangular, or polygonal shapes.

24. A directional microphone, characterized in that, The device includes the diaphragm unit as described in claim 22 or 23, and further includes a microphone signal processing chip, wherein the microphone signal processing chip acquires a first capacitance δC1 between the moving comb diaphragm and the fixed comb diaphragm, and a second capacitance δC2 between the closed-shape diaphragm and the back electrode, and outputs a differential output signal formed based on the first capacitance δC1 and the second capacitance δC2.

25. An electronic device, characterized in that, The directional microphone, including any one of claims 1-21, further includes a first housing, a first multilayer board, a first sealing assembly, a microphone connection plate, a second sealing assembly, a second multilayer board, and a second housing; The first housing, the first multilayer board, the first sealing assembly, the microphone connection plate, the directional microphone, the second sealing assembly, the second multilayer board, and the second housing are connected in sequence. The first sealing assembly is used to seal the acoustic channel of the front cavity connecting tube, and the second sealing assembly is used to seal the acoustic channel of the rear cavity connecting tube. The microphone connection plate is used to realize the electrical connection between the directional microphone and the external circuit. The first housing, the first multilayer board, the first sealing assembly, and the microphone connection plate are all provided with through holes whose positions correspond to the positions of the front cavity connecting tube. The second sealing assembly, the second multilayer board, and the second housing are all provided with through holes whose positions correspond to the positions of the rear cavity connecting tube.

26. An electronic device, characterized in that, It includes any one of the directional microphones described in claims 1-21, or the diaphragm unit described in claim 22 or 23, or the directional microphone described in claim 24.

Images