WO2023071960A1 - 声音采集方法、麦克风和电子设备 - Google Patents

声音采集方法、麦克风和电子设备 Download PDF

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Publication number
WO2023071960A1
WO2023071960A1 PCT/CN2022/126904 CN2022126904W WO2023071960A1 WO 2023071960 A1 WO2023071960 A1 WO 2023071960A1 CN 2022126904 W CN2022126904 W CN 2022126904W WO 2023071960 A1 WO2023071960 A1 WO 2023071960A1
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WIPO (PCT)
Prior art keywords
diaphragm
voltage signal
signal
microphone
laser
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PCT/CN2022/126904
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English (en)
French (fr)
Inventor
阮盛杰
谭斯克
黄林星
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华为技术有限公司
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Publication of WO2023071960A1 publication Critical patent/WO2023071960A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/08—Mouthpieces; Microphones; Attachments therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones

Definitions

  • the present application relates to the field of electronic equipment, and in particular to a sound collection method, a microphone, and an electronic device using the sound collection method or including the microphone.
  • Electronic devices have a variety of scenarios where microphones are used to pick up sound, such as telephone calls, video calls, voice assistants, remote conferences, nationwide live broadcasts, and online teaching, etc., all of which need to extract audio signals through microphones.
  • the signal-to-noise ratio of existing microphones usually does not exceed 70dB, but with the continuous improvement of use requirements, the signal-to-noise ratio of microphones needs to be increased to above 80dB in some scenarios, making it difficult for existing microphones to meet performance requirements.
  • the present application provides a sound collection method, which can improve the sound pickup signal-to-noise ratio of a microphone.
  • the present application also relates to a microphone, and an electronic device. Specifically include the following technical solutions:
  • the present application provides a sound collection method for a microphone
  • the microphone includes a laser self-mixing device and a diaphragm device
  • the diaphragm device includes a diaphragm
  • the diaphragm is used to respond to sound vibrations
  • the membrane devices are respectively used to detect the vibration of the diaphragm, and the method includes the following steps:
  • the first voltage signal is converted into an audio signal; if the first voltage signal is higher than the preset threshold, the second voltage signal is converted into an audio signal.
  • the sound collection method of the present application corresponds to a microphone that includes both a laser self-mixing device and a diaphragm device.
  • the first voltage signal can be obtained through the laser self-mixing device, and the second voltage signal can be obtained through the diaphragm device.
  • the first voltage signal and the second voltage signal are respectively signals obtained by the laser self-mixing device and the diaphragm device based on the diaphragm's response to external sound vibrations. Then, the first voltage signal is compared with a preset threshold to select to convert the first voltage signal into an audio signal, or to select to convert the second voltage signal into an audio signal.
  • the sound vibration detection of the laser self-mixing device is relatively sensitive, it can respond to sound vibrations with low sound pressure, thereby improving the response range and signal-to-noise ratio of the sound collection method of the present application.
  • the acoustic overload point of the diaphragm device is relatively high, and it can provide better sound collection effect when it is applied to a vibration scene with a large sound pressure. Therefore, by setting the preset threshold, the sound collection method can make the laser self-mixing device and the diaphragm device complement each other, and collect audio signals in their respective relatively ideal working scenarios, thereby ensuring the sound collection method of the present application. pickup effect.
  • the laser self-mixing device includes a transmitter and a receiver, and the first voltage signal is obtained through the laser self-mixing device, including:
  • the first current signal is modulated into a first voltage signal.
  • the laser self-mixing device emits laser light toward the diaphragm and receives the laser light reflected by the diaphragm to form the first current signal.
  • the laser reflected by the diaphragm will also form a self-mixing interference effect with part of the laser in the back cavity, thereby carrying the vibration information of the diaphragm, and making the first voltage signal converted from the first current signal also carry vibration information.
  • the laser self-mixing device includes a quadratic impedance amplifier and an operational amplifier, and modulates the first current signal into a first voltage signal, including:
  • the amplified first modulation voltage signal is filtered to form a first voltage signal.
  • the first modulated voltage signal after the first current signal is converted into the first modulated voltage signal, the first modulated voltage signal includes vibration information of high, medium and low frequencies. Therefore, filtering the first modulated voltage signal can filter out unnecessary high-frequency and low-frequency vibration information. Amplifying the first modulated voltage signal can increase the intensity of the first voltage signal, which facilitates the conversion of subsequent audio signals.
  • the diaphragm device is provided with a diaphragm chip, and obtaining the second voltage signal through the diaphragm device includes:
  • the strain signal formed by the displacement of the diaphragm is collected through the diaphragm chip
  • the strain signal is converted to a second voltage signal.
  • the diaphragm device senses the vibration of the diaphragm through the diaphragm chip, and then converts the displacement of the diaphragm into a strain signal, and then forms a second voltage signal based on the strain signal.
  • converting the first voltage signal or the second voltage signal into an audio signal includes:
  • Algorithm processing is performed on the first voltage signal or the second voltage signal converted into a digital signal format to obtain an audio signal.
  • the first voltage signal and the second voltage signal obtained by the processing unit are both analog signals.
  • it is necessary to first convert the analog signals into digital formats to obtain signals in digital format and convert them to audio signals. It performs algorithmic processing.
  • it also includes:
  • a control signal is formed based on the first voltage signal and output to the emitter; the control signal is used to adjust the wavelength of the laser light emitted toward the diaphragm.
  • the optimum operating point of the laser self-mixing device will change accordingly during the process of collecting the first voltage signal.
  • the wavelength corresponding to the optimum working point of the laser self-mixing device can be obtained through calculation. Accordingly, adjusting the wavelength of the laser emitted by the emitter toward the diaphragm can ensure that the laser self-mixing device is always at an optimal working point for collecting the first voltage signal.
  • a phase-locking algorithm is used to calculate the corresponding wavelength of the laser self-mixing device at the optimum working point.
  • control signal is formed based on the first voltage signal and output to the transmitter to adjust the wavelength of the laser light emitted toward the diaphragm, including:
  • the operating current of the emitter is controlled based on the control signal, so as to control the wavelength of the laser light emitted toward the diaphragm.
  • the optimal working wavelength of the laser is calculated based on the first voltage signal to form a control signal, including:
  • the optimal working wavelength of the laser is calculated based on the first voltage signal in digital format to form a control signal.
  • the operating current of the emitter is controlled based on the control signal to control the wavelength of the laser light emitted toward the diaphragm, including:
  • the operating current of the emitter is controlled based on the control signal in analog format, so as to control the wavelength of the laser light emitted by the emitter towards the diaphragm.
  • the calculation of the optimal working point of the laser self-mixing device is carried out based on the first voltage signal in digital signal format, so before the calculation, it is necessary to perform digital conversion on the first voltage signal in analog format. Then, through calculation such as a phase-locking algorithm, the optimum working wavelength of the laser light at the optimum working point of the laser self-mixing device can be obtained. Then, by controlling the size of the working current of the emitter, the wavelength of the laser can be controlled to obtain the effect of adjusting the emitter to emit laser light to the diaphragm.
  • the feedback intensity C ⁇ 1 of the laser self-mixing device is provided.
  • controlling the feedback intensity C ⁇ 1 of the laser self-mixing device can avoid phase change or noise fluctuation in the laser received by the receiver, thereby ensuring the quality of the laser received by the receiver.
  • the preset threshold is 0.1V.
  • the preset threshold value is an audio signal voltage value corresponding to 94dB-100dB.
  • the preset threshold can be set to 0.1V, or can be set to the corresponding audio signal voltage value of 94dB-100dB.
  • the laser self-mixing device has a relatively sensitive sound sensing ability, and can accurately collect sound vibrations with low sound pressure at long distances.
  • the sound sensing ability of the laser self-mixing device is affected by noise and relatively decreases. At this time, the diaphragm device can better complete the work of sound collection.
  • the present application provides an electronic device, the electronic device includes a microphone, and the microphone picks up sound by using the sound collection method provided in the first aspect of the present application.
  • the electronic device provided by the second aspect of the present application adopts the sound collection method provided by the first aspect of the present application to pick up sound, and it also has the ability to collect audio signals in two different ways, and by preset The threshold guarantees the effect of the audio signal quality.
  • the present application provides a microphone, including a substrate, a protective cover, a laser self-mixing device, a diaphragm device, and a processing unit; the protective cover and the processing unit are fixed on the substrate, and the protective cover and the substrate are enclosed to form an inner cavity.
  • the laser self-mixing device and the vibrating membrane device are fixed in the inner cavity, and are connected to the processing unit respectively;
  • the chip and the back cavity are enclosed on the substrate to form a pickup cavity;
  • the laser self-mixing device includes a transmitter and a receiver, both of which are accommodated in the pickup cavity and fixed on the substrate, and the transmitter is used to face the diaphragm
  • the laser is emitted, and the receiver is used to receive the laser reflected by the diaphragm; there are also multiple sound pickup holes on the substrate, and the sound pickup cavity communicates with the outside world through the multiple sound pickup holes.
  • an inner cavity is formed by enclosing the substrate and the protective cover to accommodate the laser self-mixing device and the diaphragm device and provide protection for both.
  • the diaphragm device passes through the diaphragm and the back cavity, and further surrounds the inner cavity with the substrate to form a pickup cavity.
  • the diaphragm device can identify the vibration of the diaphragm and form a second voltage signal.
  • the laser self-mixing device is accommodated in the sound pickup cavity, and by emitting the laser light towards the diaphragm, the laser light reflected back by the diaphragm and the back cavity can be received and induced to form a first voltage signal.
  • the microphone provided in the third aspect of the present application can apply and realize the sound collection method in the first aspect above because the laser self-mixing device and the diaphragm device are provided at the same time. That is to say, the microphone of the present application can respectively obtain the first voltage signal and the second voltage signal through the laser self-mixing device and the diaphragm device, and convert the audio signal through the preset threshold, so that the laser self-mixing device and the diaphragm device can interact with each other. As a supplement, audio signals are collected in their respective relatively ideal working scenarios to ensure the sound pickup effect of the microphone of the present application.
  • the diaphragm includes a reflection unit, and the reflection unit is located on the surface of the diaphragm facing the substrate, and the laser light emitted by the transmitter is reflected by the reflection unit and received by the receiver.
  • the laser light emitted by the transmitter can be better reflected, thereby ensuring that the receiver can effectively receive the reflected laser light.
  • the reflective unit is located at the geometric center of the diaphragm, and the positions of the transmitter and the receiver on the substrate are located within the projection area of the reflective unit on the substrate.
  • the geometric center of the diaphragm is the area with the largest amplitude
  • the reflective unit, transmitter, and receiver are all set corresponding to the geometric center of the diaphragm, which can improve the self-mixing efficiency of the reflected laser light, and is beneficial to the vibration information. extract.
  • the distance H between the reflective unit and the emitter satisfies the condition: 20um ⁇ H ⁇ 100um.
  • the distance between the reflective unit and the transmitter can be limited to control the laser reflection path and ensure the self-mixing efficiency of the laser.
  • the diaphragm device includes a diaphragm chip, and the diaphragm chip is used to detect the vibration of the diaphragm, and form a second voltage signal for transmission to the processing unit.
  • the diaphragm chip can convert the displacement of the diaphragm into a strain signal, and finally form a second voltage signal and transmit it to the processing unit.
  • the diaphragm is a piezoelectric diaphragm or a piezoresistive diaphragm
  • the diaphragm chip is a piezoelectric diaphragm chip or a piezoresistive diaphragm chip.
  • the diaphragm device can be realized by using a piezoresistive diaphragm device or a piezoelectric diaphragm device, and the corresponding diaphragm chip is a piezoresistive diaphragm chip or a piezoelectric diaphragm chip, so as to realize the second Reliable acquisition of voltage signals.
  • the thickness D of the diaphragm satisfies the condition: 0.1um ⁇ D ⁇ 1um.
  • the diaphragm is provided with a barrier layer, and the barrier layer is located on a side of the diaphragm facing the substrate, and the back chamber is fixedly connected to the diaphragm through the barrier layer.
  • the barrier layer is connected between the back cavity and the main body of the diaphragm, which can realize the insulation between the back cavity and the diaphragm, and ensure that the diaphragm chip can reliably sense the vibration of the diaphragm and form a second voltage signal.
  • the diaphragm chip is a piezoresistive diaphragm chip, and a piezoresistive sensitive unit is arranged inside the diaphragm, and the piezoresistive sensitive unit is used to sense the vibration of the diaphragm and transmit the displacement signal of the diaphragm For the piezoresistive diaphragm chip.
  • the diaphragm chip is a piezoelectric diaphragm chip
  • the diaphragm body is made of piezoelectric material with a metal layer inside. The body is used to induce the vibration of the diaphragm and generate charges. The charge is collected and the charge signal is transmitted to the piezoelectric diaphragm chip through the transmission unit.
  • the diaphragm chip converts different received signals into second voltage signals to realize the induction of diaphragm vibration.
  • the residual stress of the diaphragm is less than or equal to 50 MPa.
  • the sensitivity of the diaphragm can be controlled by monitoring the residual stress of the diaphragm.
  • the material of the diaphragm is silicon or a silicon-containing compound.
  • silicon or silicon-containing compounds are used as the material of the diaphragm, which can ensure the mechanical properties of the diaphragm and facilitate manufacture.
  • the membrane is provided with a penetrating balance hole.
  • the balance hole on the diaphragm runs through between the sound pickup cavity and the inner cavity, and the air in the inner cavity can communicate with the outside world through the balance hole and the sound pickup hole successively to ensure the pressure of the inner cavity and the sound pickup cavity balance.
  • the present application provides an electronic device, which includes the microphone provided in the third aspect above, and is used for collecting audio signals.
  • the electronic device provided by the fourth aspect of the present application includes the microphone provided by the third aspect of the present application for sound pickup, and it also has the ability to collect audio signals in two different ways, and the preset threshold guarantees The effect of audio signal quality.
  • FIG. 1 is a schematic diagram of an internal frame of an electronic device provided by the present application.
  • Fig. 2 is a schematic structural diagram of an electronic device provided by the present application.
  • Fig. 3 is a schematic structural diagram of a microphone provided by the present application.
  • FIG. 4 is a schematic diagram of an exploded structure of a microphone provided by the present application.
  • FIG. 5 is a schematic diagram of an exploded structure of a diaphragm device in a microphone provided by the present application
  • Fig. 6 is a schematic cross-sectional structure diagram of an inner cavity in a microphone provided by the present application.
  • Fig. 7 is a schematic plan view of the sound pickup cavity in a microphone provided by the present application.
  • Fig. 8 is a partial cross-sectional structural schematic diagram of a diaphragm device in a microphone provided by the present application.
  • FIG. 9 is a schematic diagram of the steps of a method for manufacturing a diaphragm device in a microphone provided by the present application.
  • Fig. 10a-Fig. 10h are respectively the structural schematic diagrams of each step of a method for manufacturing a diaphragm device in a microphone provided by the present application;
  • Fig. 11 is a schematic diagram of a partial cross-sectional structure of a diaphragm device in a microphone provided by the present application under another embodiment
  • Fig. 12 is a flow chart of a sound collection method provided by the present application.
  • Fig. 13 is a circuit diagram of signal processing in a microphone provided by the present application.
  • FIG. 14 is a flow chart of another embodiment of a sound collection method provided by the present application.
  • FIG. 15 is a flow chart of another embodiment of a sound collection method provided by the present application.
  • Fig. 16 is a circuit diagram of another embodiment of signal processing in a microphone provided by the present application.
  • FIG. 1 is a schematic diagram of an internal frame of an electronic device 200 provided in the present application.
  • an electronic device 200 includes a control chip 201 and a microphone 100 provided in this application.
  • the microphone 100 is electrically connected to the control chip 201 , and the microphone 100 is used to sense external sound vibrations and form an audio signal to transmit to the control chip 201 .
  • the control chip 201 After the control chip 201 receives the audio signal sensed by the microphone 100 , it can send the audio signal to the outside, so as to realize the remote communication function of the electronic device 200 .
  • the audio signal here can also be understood as an audio code, and the audio code can be sent out in the form of a communication signal.
  • the electronic device 200 corresponding to the present application may be a terminal product such as a mobile phone, a tablet, a notebook computer, a desktop computer, or a television.
  • the control chip 201 after the control chip 201 receives the audio signal sensed by the microphone 100, it can also parse out information such as instructions contained in the audio signal (encoding), and then respond to the user's voice control operation.
  • the electronic device 200 corresponding to this application may also be the above-mentioned terminal product, or a smart home appliance, etc.
  • the electronic device 200 may also include an audio decoding unit 202, an audio amplification unit 203, and a speaker 204, and the control chip 201 is also sequentially connected with the audio decoding unit 202, the audio amplification unit 203, and the speaker 204 at the rear end relative to the microphone 100.
  • the speaker 204 is electrically connected, and the control chip 201 can send an audio signal to the speaker 204 after receiving external sound vibrations sensed by the microphone 100 .
  • the electronic device 200 can achieve the function of voice interaction with the user through sound collection by the microphone 100 .
  • FIG. 2 is a schematic structural diagram of an electronic device 200 provided in the present application.
  • each microphone 100 is arranged in the electronic device 200 , and each microphone 100 is distributed at different positions on the outer edge of the electronic device 200 for collecting sound vibrations transmitted from different positions of the electronic device 200 .
  • Each microphone 100 is electrically connected to the control chip 201 for transmitting audio signals.
  • the eight microphones 100 can also be numbered one by one, and the control chip 201 can determine the position of the microphone 100 that currently senses the audio signal in the electronic device 200 based on the audio signals received by the microphones 100 with different numbers. , that is, the position of the sound source emitting the sound vibration relative to the electronic device 200 is judged, so as to achieve the function of position identification.
  • the electronic device 200 can selectively receive the microphone 100 in the direction area based on the determined position of the sound source relative to the electronic device 200 to collect the audio signal, so as to realize the directional function of the audio signal collection.
  • the control chip 201 can also integrate multiple audio signals into one, and then send them out or perform operations such as voice interaction and command recognition. In order to improve the accuracy of sound vibration collection by the electronic device 200 .
  • the number and distribution position of the microphones 100 in the electronic device 200 can also be set arbitrarily based on actual usage scenarios, which is not particularly limited in this application.
  • FIG. 3 shows a schematic structural diagram of a microphone 100 provided in the present application.
  • the microphone 100 provided in this application includes a substrate 10 and a protective cover 20 .
  • the protective cover 20 includes a protective plate 21 and a protective wall 22 .
  • the protective wall 22 surrounds the peripheral edge of the protective plate 21 , and the protective wall 22 is also fixedly connected with the substrate 10 , so that the protective cover 20 is fixedly connected with the substrate 10 as a whole.
  • the protective cover 20 and the substrate 10 enclose to form an inner cavity 23 (see FIG. 6 ).
  • FIG. 4 shows a schematic diagram of an exploded structure of the microphone 100 .
  • the microphone 100 also includes a diaphragm arrangement 30 .
  • the diaphragm device 30 is accommodated in the cavity 23 formed by the protective cover 20 and the substrate 10 , and the diaphragm device 30 is fixedly connected to the substrate 10 .
  • the microphone 100 further includes a processing unit 40, which may be an application specific integrated circuit (Application Specific Integrated Circuit, ASIC).
  • the processing unit 40 is also fixed on the substrate 10 and is also accommodated in the cavity 23 .
  • the processing unit 40 is fixedly connected to the substrate 10 , and the processing unit 40 is also electrically connected to the diaphragm device 30 .
  • the processing unit 40 may also be located outside the protective cover 20 , that is, the processing unit 40 may be located outside the inner cavity 23 . At this time, the processing unit is also fixedly connected to the substrate 10 and electrically connected to the diaphragm device 30 at the same time.
  • FIG. 5 shows a schematic diagram of an exploded structure of the diaphragm device 30 .
  • the diaphragm device 30 may be a micro-electro-mechanical system (Micro Electrical Mechanical System, MEMS), which includes a diaphragm 31 and a back cavity 32.
  • MEMS Micro Electrical Mechanical System
  • the diaphragm 31 is in the form of a thin film, and its material may be silicon or silicon-containing compounds, or piezoelectric materials may also be used in some embodiments.
  • the back cavity 32 is hollow and ring-shaped, and a through hole 321 is formed therein. In the diagram of FIG. 5 , the back cavity 32 is circular, and the corresponding through hole 321 is also set to be circular, so that the back cavity 32 is in the shape of a hollow ring.
  • the back cavity 32 can also be rectangular, oval, etc., and the shape of the corresponding through hole 321 is also set to match the shape of the back cavity 32, so that the back cavity 32 is in the shape of a rectangular ring or an elliptical ring. shape.
  • the diaphragm 31 is fixed on one side of the back cavity 32 and covers the through hole 321 .
  • the side of the back cavity 32 away from the diaphragm 31 is fixedly connected to the substrate 10, so that the diaphragm device 30 and the substrate 10 are surrounded to form a sound pickup cavity 33 (please refer to the cross-sectional structure of the inner cavity 23 in the microphone 100 shown in FIG. 6 ) .
  • the sound pickup cavity 33 is accommodated in the inner cavity 23 .
  • the substrate 10 is provided with at least one sound pickup hole 11 in the area corresponding to the sound pickup cavity 33. Specifically, please refer to FIG.
  • the projection of the through hole 321 of the back cavity 32 on the substrate 10 forms a receiving area 322 , and a plurality of sound pickup holes 11 are located in the receiving area 322 .
  • the at least one sound pickup hole 11 runs through the base plate 10 , thereby realizing communication between the sound pickup cavity 33 and the outside. External sound vibrations can enter the sound pickup cavity 33 through each sound pickup hole 11 and cause the diaphragm 31 to vibrate.
  • the diaphragm device 30 can convert the displacement and strain of the diaphragm 31 into electrical signals, realize the collection and capture of external sound vibrations, and form audio signals to be transmitted to the processing unit 40 .
  • the shape, size and number of the sound pickup holes 11 are not particularly limited.
  • the number of sound pickup holes 11 is four, and in other embodiments, the number of sound pickup holes 11 can also be other values.
  • the shape and size of the sound pickup hole 11 can be set arbitrarily, as long as it can be connected between the sound pickup cavity 33 and the external space, the effect of allowing external sound vibrations to enter the sound pickup cavity 33 from the sound pickup hole 11 can be achieved.
  • FIG. 8 schematically shows an implementation manner inside the diaphragm device 30 .
  • the diaphragm 31 is realized by a piezoresistive diaphragm.
  • the diaphragm 31 includes a body 311 , a reflective unit 312 , a barrier layer 313 , a piezoresistive sensitive unit 314 , a transmission unit 315 , and a protective layer 316 .
  • the material of the body 311 is silicon or a compound containing silicon.
  • the body 311 is film-shaped and has a first plane 311a and a second plane 311b opposite to each other.
  • the first plane 311 a is the outer surface of the body 311 facing the substrate 10
  • the second plane 311 b is the outer surface of the body 311 facing away from the substrate 10
  • the direction from the first plane 311a to the second plane 311b is the thickness direction of the body 311
  • the direction parallel to the first plane 311a and the second plane 311b is the plane direction of the body 311 .
  • the barrier layer 313 is connected between the body 311 and the back cavity 32, that is, the barrier layer 313 is located on the first plane 311a, which is used to realize the fixed connection between the diaphragm 31 and the back cavity 32, and make the diaphragm 31 and the back cavity 32 overall insulation.
  • the reflection unit 312 is also located on the first plane, and in the illustration of FIG. 8 , the reflection unit 312 is also disposed at the geometric center of the body 311 .
  • the reflection unit 312 is disposed toward the interior of the sound pickup cavity 33 .
  • the protection layer 316 is located on one side of the second plane 311b, and the protection layer 316 is disposed toward the outside of the sound pickup cavity 33 .
  • the protective layer 316 is used to protect the main body 311 and other components of the diaphragm 31 .
  • the piezoresistive sensitive unit 314 and the transmission unit 315 are located between the reflection unit 312 and the protective layer 316 .
  • the piezoresistive sensitive units 314 are also distributed along the plane direction of the body 311 .
  • the piezoresistive sensing unit 314 is used to sense the vibration displacement generated by the body 311 .
  • the main body 311 is excited by the external sound vibration to generate a vibration displacement, and the piezoresistive sensitive unit 314 generates a strain signal with the vibration displacement of the main body 311, and transmits the strain signal via its communication Unit 315 passes to the backend.
  • the diaphragm 31 is further provided with a piezoresistive diaphragm chip 341 corresponding to the piezoresistive sensing unit 314 .
  • the piezoresistive diaphragm chip 341 can be disposed on the diaphragm device 30 or integrated in the processing unit 40 .
  • the piezoresistive diaphragm chip 341 is electrically connected to the piezoresistive sensing unit 314, and is used to convert the strain signal sensed by the piezoresistive sensing unit 314 into a voltage signal (specifically, the second voltage signal V2), and convert the voltage signal transmitted to the processing unit 40.
  • the piezoresistive diaphragm chip 341 when the piezoresistive diaphragm chip 341 is arranged on the diaphragm device 30, specifically on the second plane 311b of the diaphragm 31, it can be electrically connected to the piezoresistive sensitive unit 314 directly through the transmission unit 315.
  • the piezoresistive diaphragm chip 341 When the piezoresistive diaphragm chip 341 is integrated in the processing unit 40, it needs to cooperate with the transmission unit 315 through the transmission line 319, and then conducts with the piezoresistive sensitive unit 314.
  • Both of the above two configurations of the piezoresistive diaphragm chip 341 can realize the conduction between the piezoresistive diaphragm chip 341 and the piezoresistive sensing unit 314 , and enable the piezoresistive diaphragm chip 341 to collect strain signals.
  • its overall thickness may be between 0.1 um and 1 um, for example, 0.9 um, so as to ensure its sound pressure responsiveness and displacement sensitivity to external sound vibrations.
  • the area of the diaphragm 31 is between 0.3 mm 2 and 4 mm 2 , such as 1 mm 2 .
  • the residual stress of the diaphragm 31 is not more than 50 MPa to ensure the sensitivity of the diaphragm 31 .
  • the reflective unit 312 its shape may be circular, and the radius of the reflective unit 312 is between 10 um and 1000 um, such as 60 um, to obtain a larger reflective area.
  • the thickness of the reflective unit 312 may be between 10nm and 200nm to ensure the ability to reflect light. Further, the offset of the geometric center of the reflection unit 312 relative to the geometric center of the body 311 needs to be controlled within 10 um.
  • the thickness of the piezoresistive sensing unit 314 can be between 100nm and 500nm, for example, 180nm, so as to form a preset resistance value and realize the collection of strain signals.
  • the thickness of the protection layer 316 is between 50nm and 1000nm, such as 200nm, to ensure the protection effect.
  • a balance hole 317 is further provided in the diaphragm 31 .
  • the balance hole 317 runs through the diaphragm 31 along the thickness direction of the diaphragm 31 , and the balance hole 317 communicates between the sound pickup cavity 33 and the inner cavity 23 .
  • the vibration of the sheet 31 creates a disturbance.
  • the opening of the balance hole 317 can balance the pressure between the sound pickup cavity 33 and the inner cavity 23 , thereby ensuring the vibration effect of the diaphragm 31 .
  • the diameter of the balance hole 317 may be between 0.5um and 5um, for example, 1.5um.
  • the structure of the piezoresistive diaphragm chip 341 also needs to be limited, so as to prevent the piezoresistive diaphragm chip 341 from affecting the vibration effect of the diaphragm 31 .
  • the shape of the piezoresistive diaphragm chip 341 is rectangular, and the combination of side lengths thereof may be between 0.5 ⁇ 0.5 mm and 5 ⁇ 5 mm, for example, 1.4 ⁇ 1.4 mm.
  • the thickness of the piezoresistive diaphragm chip 341 may be between 150um and 500um, such as 220um.
  • FIG. 9 and FIG. 10a-FIG. 10h respectively schematically illustrating the manufacturing method steps of the diaphragm device 30 of the present application.
  • the diaphragm device 30 of the present application can be unfolded and obtained through the following steps:
  • one thermal oxide layer 313a is located on one outer surface of the silicon substrate, and the other thermal oxide layer 313b is located inside the silicon substrate, and is spaced from the thermal oxide layer 313a on the outer surface.
  • the piezoresistive sensitive unit 314 is located between the two thermal oxide layers 313a and 313b, and the piezoresistive sensitive unit 314 is patterned synchronously during the fabrication process.
  • the depth of the part of the transmission unit 315 a in the silicon substrate is equal to the depth of the piezoresistive sensitive unit 314 , so that the part of the transmission unit 315 a communicates with each patterned piezoresistive sensitive unit 314 .
  • the thermal oxide layer 313a is etched to form a protective layer 316 of the diaphragm 31, and the protective layer 316 has a via hole 315b formed by etching.
  • the metal on the protection layer 316 forms a conductive structure layer located outside the protection layer 316, and this part of the metal conducts with the part of the transmission unit 315a made in step S103 through the metal filled in the via hole 315b, and then in step S105
  • the manufactured part of the transmission unit 315c and the other part of the transmission unit 315a produced in step S103 together form the transmission unit 315 to achieve the effect of leading the strain signal in the piezoresistive sensitive unit 314 to the outside of the protective layer 316 .
  • the transmission unit 315 can be directly connected to the piezoresistive diaphragm chip 341 , or connected to the diaphragm chip 341 through the transmission line 319 .
  • this step can also complete the fabrication of the balance hole 317 .
  • the etching of this part of the silicon substrate is center etching, and the material on the periphery of the silicon substrate is reserved to form the back cavity 32 of the diaphragm device 30 .
  • the silicon base material between another thermal oxide layer 313b and the passivation layer 316 is formed as the body 311 of the diaphragm 31 .
  • step S107 remove part of the thermal oxide layer 313b exposed in step S106 by a rinsing process (see FIG. 10g);
  • the remaining thermal oxide layer 313 b after the rinsing process is formed as the barrier layer 313 of the membrane 31 , which is connected between the body 311 and the back chamber 32 .
  • the thermal oxide layer 313b is partially removed, the first plane 311a of the body 311 is also exposed.
  • the rinsing process may use a hydrofluoric acid (Hydrofluoric acid, HF) reagent for rinsing.
  • HF hydrofluoric acid
  • the reflection unit 312 can be made of aluminum or aluminum alloy.
  • the diaphragm device 30 provided in the embodiment of the present application can be manufactured, and the position and function between various components and layer structures can be ensured.
  • FIG. 11 illustrates the structure of another implementation of the diaphragm device 30 .
  • the membrane 31 is realized by a piezoelectric membrane.
  • the membrane 31 also includes a body 311 , a reflection unit 312 , a barrier layer 313 , a transmission unit 315 , and a protection layer 316 .
  • the main body 311 is made of piezoelectric material and is also in the form of a film as a whole, which has a first plane 311a and a second plane 311b opposite to each other.
  • the first plane 311 a is the outer surface of the body 311 facing the substrate 10
  • the second plane 311 b is the outer surface of the body 311 facing away from the substrate 10 .
  • the barrier layer 313 is connected between the main body 311 and the back cavity 32, the reflective unit 312 is also located on the first plane 311a, and the protective layer 316 is located on the side of the second plane 311b, which is used to form a structure for the main body 311 and the rest of the diaphragm 31. protection.
  • a metal layer 318 and a transmission unit 315 are disposed between the first plane 311 a and the second plane 311 b of the body 311 .
  • the number of the metal layer 318 can be one or more layers, and it is shown as two layers in FIG. 11 .
  • the transmission unit 315 is electrically connected to each metal layer 318 respectively, and the transmission unit 315 also partially protrudes from the second plane 311b.
  • the protection layer 316 is also located on the side of the transmission unit 315 facing away from the reflection unit 312 , for covering and protecting the transmission unit 315 protruding from the second plane 311 b.
  • the main body 311 After the external sound vibration is transmitted from the sound pickup hole 11 to the sound pickup cavity 33 , the main body 311 is excited by the external sound vibration to generate a vibration displacement.
  • the body 311 made of piezoelectric material will form electric charge itself.
  • the metal layer 318 disposed in the body 311 realizes the collection of electric charges, and forms the electric charge signal to transmit to the rear end through the transmission unit 315 communicated therewith.
  • the diaphragm 31 is also provided with a piezoelectric diaphragm chip 342 correspondingly.
  • the piezoelectric diaphragm chip 342 can be disposed on the diaphragm device 30 or integrated in the processing unit 40 .
  • the piezoelectric diaphragm chip 342 is electrically connected to the transmission unit 315 for converting the charge signal collected by the metal layer 318 into a second voltage signal V2 and transmitting the second voltage signal V2 to the processing unit 40 .
  • the diaphragm device 30 realized by the piezoelectric diaphragm as shown in FIG.
  • the embodiment of 317 can be set with reference to the above-mentioned piezoresistive diaphragm device 30 to improve the sensitivity of the diaphragm device 30 . Therefore, the diaphragm device 30 of the present application adopts the above-mentioned piezoresistive or piezoelectric embodiments, and both can realize reliable collection of external sound vibrations.
  • the microphone 100 of the present application further includes a laser self-mixing device 60 .
  • the laser self-mixing device 60 is accommodated in the pickup cavity 33 , which includes a transmitter 61 and a receiver 62 . Both the transmitter 61 and the receiver 62 are fixed relative to the substrate 10, wherein the transmitter 61 may adopt a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL) for emitting laser light toward the reflection unit 312, and the receiver 62 is used for The laser light reflected back by the reflection unit 312 is received.
  • VCSEL Vertical Cavity Surface Emitting Laser
  • the laser light emitted by the transmitter 61 and the laser light reflected by the reflection unit 312 will form diffraction in the pickup cavity 33, and the part of the diffracted laser light will also irradiate the first plane 311a of the diaphragm 31 and the back cavity 32. on the inner wall, and the reflected part is received by the receiver 62. Furthermore, the vibration of the diaphragm 31 will also cause part of the laser light to be reflected to the inner wall of the back cavity 32 . When external sound vibrations cause the diaphragm 31 to vibrate, the laser light reflected by the reflection unit 312 will carry the vibration information of the diaphragm 31 .
  • the receiver 62 can compare the laser emitted by the transmitter 61 with the mixed laser, extract the current signal (specifically the first current signal A1) and convert it into a voltage signal (specifically is transmitted to the processing unit 40 as the first voltage signal V1).
  • the transmitter 61 and the receiver 62 are overlapped, the transmitter 61 is fixed on the substrate 10 , and the receiver 62 is located on the side of the transmitter 61 away from the substrate 10 . Further, the diaphragm 31 is arranged parallel to the substrate 10 , and its first plane 311 a is perpendicular to the transmitter 61 and the receiver 62 at the same time. Thus, the reflection unit 312 is also arranged perpendicular to the transmitter 61 and the receiver 62 . And the positions of the transmitter 61 and the receiver 62 on the substrate 10 are within the projection range of the reflection unit 312 on the substrate 10 .
  • the transmitter 61 emits laser light toward the diaphragm 31 in a direction perpendicular to the substrate 10 , and the laser light is vertically reflected by the reflection unit 312 and then received by the receiver 62 , which can shorten the flight distance of the laser light in the pickup cavity 33 .
  • the pickup cavity 33 can be defined as the front cavity of the microphone 100 , and the distance between the diaphragm 31 and the substrate 10 is defined as the height of the front cavity.
  • the space of the inner cavity 23 except the sound pickup cavity 33 is defined as the rear cavity of the microphone 100 .
  • the height of the diaphragm 31 relative to the inner surface of the protective plate 21 is then defined as the height of the rear cavity.
  • the distance H between the reflective unit 312 and the emitter 61 is defined to satisfy the condition: 20um ⁇ H ⁇ 100um.
  • This limitation controls the distance between the emitter 61 and the diaphragm 31, and because the distance between the emitter 61 and the diaphragm 31 is limited, the flying distance of the laser in the pickup cavity 33 is controlled, thereby reducing the reception
  • controlling the distance between the emitter 61 and the reflection unit 312 also controls the distance between the substrate 10 and the diaphragm 31 synchronously. That is, through the above definition, the height of the front cavity of the microphone 100 is controlled. On the premise that the space height of the inner cavity 23 is constant, controlling the height of the front cavity of the microphone 100 increases the height of the rear cavity of the microphone 100 , and a larger height of the rear cavity is also conducive to improving the signal-to-noise ratio of the diaphragm device 30 .
  • the body 311 only adopts a layer structure of one or two layers, and the microphone 100 can achieve a better working state, compared with the multi-layer structure in the prior art
  • the thickness of the diaphragm 31 in the present application is thinner, and the rear cavity space obtained correspondingly is also larger, which is beneficial to improve the signal-to-noise ratio of the diaphragm device 30 .
  • the microphone 100 of the present application can not only collect external sound vibrations through the diaphragm device 30 , but also collect external sound vibrations through the laser self-mixing device 60 .
  • the two sound vibration collection methods can complement each other, or use a fusion algorithm to ensure that the microphone 100 can achieve a better sound collection effect.
  • the electronic device 200 using the microphone 100 of the present application also improves its audio collection capability because of the better sound collection effect of the microphone 100 .
  • first voltage signal V1 If the first voltage signal V1 is lower than or equal to the preset threshold V0, convert the first voltage signal V1 into an audio signal; if the first voltage signal V1 is higher than the preset threshold V0, convert the second voltage signal V2 for the audio signal.
  • the sound collection method of the present application is developed based on the above-mentioned microphone 100 including the laser self-mixing device 60 and the diaphragm device 30 . Specifically, in the process of step S100 , when external sound vibration occurs, the sound wave is transmitted from the sound pickup hole 11 into the sound pickup cavity 33 , and causes the diaphragm 31 to vibrate.
  • the diaphragm device 30 itself can sense the vibration of the diaphragm 31, and use a piezoelectric or piezoresistive method to sense the displacement of the diaphragm 31 to form a second voltage signal V2 and transmit it to the processing unit 40; while the laser self-mixing
  • the device 60 also monitors the vibration of the diaphragm 31 at the same time, and generates a first voltage signal V1 and transmits it to the processing unit 40 .
  • the two voltage signals acquired by the processing unit 40 are formed based on the same external sound vibration, that is, the sound vibration collected by the laser self-mixing device 60 and the diaphragm device 30 is the sound vibration in the same environment, Both the first voltage signal V1 and the second voltage signal V2 are used to reflect the sound vibration in the same environment.
  • the processing unit 40 After the processing unit 40 acquires the first voltage signal V1 and the second voltage signal V2 respectively, it will judge the value of the first voltage signal V1 based on the preset threshold V0. That is, the processing unit 40 compares the first voltage signal V1 with the preset threshold V0, and processes the first voltage signal V1 or the second voltage signal V2 based on the comparison result. Specifically, when the first voltage signal V1 is lower than or equal to the preset threshold V0, the processing unit 40 selects the first voltage signal V1 and performs processing to convert it into an audio signal output to the rear end; and when the first voltage signal V1 When V1 is higher than the preset threshold V0, the processing unit 40 selects the second voltage signal V2 for processing and converts it into an audio signal output to the rear end.
  • the two devices Due to the difference in sound collection principles of the laser self-mixing device 60 and the diaphragm device 30 , the two devices also have their own advantages in sound collection. Among them, the laser self-mixing device 60 is relatively more sensitive, and it can be used to collect sound vibration signals with relatively small sound vibration energy and low sound pressure; The noise of the device 60 is increased, and the signal-to-noise ratio is decreased. At the same time, its acoustic overload point (Acoustic Overload Point, AOP) is also relatively low, and the overall ability to recognize the sound is reduced.
  • AOP Acoustic Overload Point
  • the diaphragm device 30 has a better ability to identify scenes with higher sound pressure, can control the signal-to-noise ratio of the signal, and has a higher acoustic overload point.
  • the energy of external sound vibration can be identified by the magnitude of the sound pressure.
  • Responding to the microphone 100 of the present application it can be identified and distinguished by the value of the collected first voltage signal V1 or by the collected value of the second voltage signal V2.
  • the sound collection method of the present application can control the microphone 100 by setting the preset threshold V0 to use the laser self-mixing device 60 to collect sound vibrations in a scene with a relatively low sound pressure, so as to improve the sensitivity of the microphone 100 and broaden the microphone 100 range.
  • the microphone 100 of the present application uses the diaphragm device 30 to collect sound vibrations, so as to ensure the signal-to-noise ratio of the signal and increase the acoustic overload point of the microphone 100.
  • both the first voltage signal V1 and the second voltage signal V2 are used to reflect sound vibrations in the same environment, they can be regarded as synchronous in time.
  • the processing unit 40 switches from processing the first voltage signal V1 to processing the second voltage signal V2, or the processing unit switches from processing the second voltage signal V2 to processing the first voltage signal V1, because the time between the two signals Synchronization characteristics without signal out-of-synchronization or frame loss, thereby ensuring that the microphone 100 can continuously collect external sound vibrations and convert them into continuous audio signals.
  • the preset threshold V0 is not a unique value either.
  • the preset threshold V0 can be set to 0.1V, that is, when the value of the first voltage signal V1 collected by the laser self-mixing device 60 is lower than or equal to 0.1V, the processing unit 40 will convert the first voltage signal to V1 is processed as an audio signal; when the value of the first voltage signal V1 is higher than 0.1V, the processing unit 40 processes the second voltage signal V2 as an audio signal.
  • the preset threshold can also be defined as the voltage value formed by the laser self-mixing device 60 when collecting the corresponding audio signal of 94dB-100dB, which can also ensure that the laser self-mixing device 60 and the diaphragm
  • the devices 30 each collect sound vibrations in their more ideal working (ie, sound pressure) scenarios.
  • the preset threshold V0 may be a certain numerical point, or may be a certain numerical range. Because the respective ideal working scenes of the diaphragm device 30 and the laser self-mixing device 60 may have a partially overlapping area, that is, in the overlapping area (that is, the range of the sound pressure), the diaphragm device 30 and the laser self-mixing device 60 are both It can achieve better sound and vibration collection effect.
  • the signal switching mode of the processing unit 40 may also be set to a certain extent. For example, when the processing unit 40 is converting the audio signal based on the first voltage signal V1, if the first voltage signal V1 does not exceed the upper limit of the preset threshold V0, the processing unit 40 can be controlled to continue converting the audio signal based on the first voltage signal V1.
  • the processing unit 40 when the processing unit 40 is converting the audio signal based on the second voltage signal V2, if the first voltage signal V1 is not lower than the lower limit of the preset threshold V0, the processing can be controlled
  • the unit 40 continuously converts the audio signal based on the second voltage signal V2, which can also ensure the continuity of the audio signal.
  • the method of this embodiment also avoids signal out-of-synchronization or frame loss that may be caused by the processing unit 40 frequently switching its processing signal lines.
  • step S100 for "obtaining the first voltage signal V1 through the laser self-mixing device 60" in step S100, the following sub-steps may be included:
  • the signal induced by it is a current signal (ie, the first current signal A1 ).
  • the preset threshold V0 of the method of the present application is a voltage signal, so the first current signal A1 needs to be modulated to convert it into the first voltage signal V1 before the processing unit 40 can compare the first voltage signal V1 with the preset threshold V0 is compared and judged.
  • the laser signal received by the receiver 62 may also be a laser beam formed by self-mixing in the pickup cavity 33 .
  • step S130 of "modulating the first current signal A1 into the first voltage signal V1" also includes the following sub-steps:
  • FIG. 13 illustrates a circuit diagram of signal processing in the microphone 100 of the present application.
  • the laser self-mixing device 60 is further provided with a quadratic impedance amplifier 63 , an operational amplifier 64 , a low-pass filter 65 , and a high-pass filter 66 .
  • the impedance amplifier 63 is electrically connected with the receiver 62, and the impedance amplifier 63 is used for converting the first current signal A1 into the first modulated voltage signal VT1;
  • the operational amplifier 64 is electrically connected with the impedance amplifier 63, and the operational amplifier 64 is used for To amplify the first modulation voltage signal VT1 to increase the intensity of the first modulation voltage signal VT1, so that the amplified first modulation voltage signal VT1 can match the data processing requirements of the processing unit 40;
  • the low-pass filter 65 and the high-pass filter 66 is successively connected to the operational amplifier 64, and is used for respectively performing low-pass filtering and high-pass filtering on the amplified first modulation voltage signal VT1 to form the first voltage signal V1.
  • the audio range that can be received by the human ear is limited, and part of the vibration information carried in the first modulation voltage signal VT1 is beyond the audio receiving range of the human ear after being converted into an audio signal. Therefore, after filtering the amplified first modulated voltage signal VT1, vibration information outside the audio receiving range of the human ear can be screened out, and the first voltage signal V1 formed after the amplified first modulated voltage signal VT1 is filtered is only Vibration information within the audio receiving range of the human ear is retained, which can reduce the workload of the processing unit 40 .
  • the "obtaining the second voltage signal V2 through the diaphragm device 30" in step S100 may include the following sub-steps:
  • the diaphragm device 30 of the present application needs to sense the vibration of the diaphragm 31 through the diaphragm chip in the process of collecting external sound vibrations, and then convert the displacement of the diaphragm 31 into a strain signal.
  • the second voltage signal V2 is then formed based on the strain signal.
  • the diaphragm chip may be a piezoresistive diaphragm chip 341 or a piezoelectric diaphragm chip 342 .
  • the strain signal is specifically a charge signal, that is, the collected charge generated by the deformation of the body 311 of the piezoelectric material during vibration, and then converts the charge signal into a second Voltage signal V2.
  • the working process of the laser self-mixing device 60 to form the first voltage signal V1 belongs to two different processing circuits working separately and synchronously running the completed operations.
  • the sequence of the above serial numbers does not represent the sequence of the specific working process of the microphone 100 , and the two are actually parallel.
  • the present application may also include the following sub-steps when step S200 "converting the first voltage signal V1 or the second voltage signal V2 into an audio signal":
  • the processing unit 40 includes a conversion module 41 and a processing module 42 .
  • the first voltage signal V1 input from the laser self-mixing device 60 is in an analog signal format
  • the second voltage signal V2 input from the diaphragm device 30 is also in an analog signal format.
  • the processing module 42 processes the first voltage signal V1 or the second voltage signal V2
  • the first voltage signal V1 and the second voltage signal V2 need to be digitally converted by the conversion module 41, so that they are converted from analog signals to After the digital signal
  • the conversion module 41 transmits the first voltage signal V1 and the second voltage signal V2 in digital signal format to the processing module 42, and the processing module 42 processes them into audio signals.
  • step S100 “obtaining the first voltage signal V1 through the laser self-mixing device 60”
  • the method may further include:
  • the laser self-mixing device 60 in the process of collecting the first voltage signal V1 its optimal operating point (or described as the optimal operating intensity and frequency of the laser) will also change accordingly .
  • the processing unit 40 can calculate the current optimal working point of the laser self-mixing device 60 through methods such as a phase-locking algorithm. At this time, the processing unit 40 can synchronously analyze the wavelength of the laser light emitted by the laser self-mixing device 60 when it works at the optimum working point.
  • the wavelength of the laser light emitted by the laser self-mixing device 60 can be controlled, thereby ensuring that the laser self-mixing device 60 is always at an optimal working point for collecting the first voltage signal V1.
  • the step S300 of "using a phase-locking algorithm based on the first voltage signal V1 to adjust the wavelength of the laser light emitted by the emitter 61 toward the diaphragm 31" may also include the following sub-steps:
  • step S310 the following sub-steps may also be included:
  • step S320 the following sub-steps may be included:
  • the processing unit 40 includes a processing module 42 .
  • the calculation of the optimal working point of the laser self-mixing device 60 is carried out by the processing module 42 based on the first voltage signal V1 in digital signal format. Therefore, before the optimum working wavelength of the laser is calculated, the conversion module 41 is required to perform digital format conversion on the first voltage signal V1 in analog format. After the calculation is completed, the processing module 42 needs to send the calculation result back to the conversion module 41 , and convert the calculation result in digital format into an analog control signal in analog signal format through the conversion module 41 . Then, the transmitter 61 receives the analog control signal and controls the size of the working current to achieve the purpose of controlling the wavelength of the laser light it emits.
  • step S310 “convert the first voltage signal V1 in analog format to a digital format” can be realized through S210 "convert the first voltage signal V1 or the second voltage signal V2 to a digital signal format”.
  • the method of the present application may also include:
  • the feedback intensity of the laser self-mixing device 60 can be understood as the laser emitted by the transmitter 61, after self-mixing in the pickup cavity, combined with the propagation medium gain, optical loss and phase superposition, Intensity and frequency changes relative to the initial emitted laser light.
  • the feedback intensity is related to the height of the front cavity of the microphone 100 , the reflectivity of the reflection unit 312 , the line width of the laser, the frequency of the laser, and the height of the resonant cavity of the laser self-mixing device 60 .

Abstract

本申请提供一种用于麦克风的声音采集方法。麦克风包括激光自混合装置和振膜装置，其中振膜装置包括用于响应声音振动的膜片。激光自混合装置和振膜装置分别用于检测膜片的振动。本方法通过激光自混合装置获取第一电压信号，并同时通过振膜装置获取第二电压信号；若第一电压信号低于或等于预设阈值，则将第一电压信号转换为音频信号；若第一电压信号高于预设阈值，则将第二电压信号转换为音频信号。本申请方法可以通过两种不同的方式进行音频信号的采集，进而通过预设阈值在两路信号之间进行切换，选取更匹配的信号转换为音频信号，可以保证音频信号的质量。本申请还涉及一种麦克风，以及一种电子设备。

Description

声音采集方法、麦克风和电子设备
本申请要求于2021年10月29日提交中国专利局，申请号为202111276854.9、申请名称为“声音采集方法、麦克风和电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电子设备领域，尤其涉及一种声音采集方法、一种麦克风、以及一种采用该声音采集方法或包括该麦克风的电子设备。
背景技术
电子设备具有多种使用麦克风拾音的场景，如电话、视频通话、语音助手、远程会议、全民直播、以及在线教学等，都需要通过麦克风提取音频信号。现有的麦克风信噪比通常不超过70dB，但随着使用需求的不断提升，部分场景中需要将麦克风的信噪比提升至80dB以上，导致现有麦克风难以满足性能需求。
发明内容
本申请提供一种声音采集方法，可以提升麦克风的拾音信噪比。本申请还涉及一种麦克风，以及一种电子设备。具体包括如下技术方案：
第一方面，本申请提供一种声音采集方法，用于麦克风，麦克风包括激光自混合装置和振膜装置，其中振膜装置包括膜片，膜片用于响应声音振动，激光自混合装置和振膜装置分别用于检测膜片的振动，本方法包括如下步骤：
通过激光自混合装置获取第一电压信号，并同时通过振膜装置获取第二电压信号；
若第一电压信号低于或等于预设阈值，则将第一电压信号转换为音频信号；若第一电压信号高于预设阈值，则将第二电压信号转换为音频信号。
本申请声音采集方法对应到同时包括激光自混合装置和振膜装置的麦克风。通过激光自混合装置可以获取第一电压信号，通过振膜装置可以获取第二电压信号。其中，第一电压信号和第二电压信号分别为激光自混合装置和振膜装置基于膜片对外界声音振动的响应所获得的信号。然后，将第一电压信号与预设阈值进行比较，以选择将第一电压信号转换形成音频信号，或选择将第二电压信号转换形成音频信号。
因为激光自混合装置的声音振动检测相对灵敏，可以对小声压的声音振动形成响应，进而提升了本申请声音采集方法的响应范围和信噪比。而振膜装置的声学过载点相对较高，其应用于较大声压振动场景中时，可以提供更好的声音采集效果。由此，本声音采集方法通过对预设阈值的设置，可以使得激光自混合装置与振膜装置相互形成补充，在各自相对理想的工作场景下进行音频信号的采集，进而保证本申请声音采集方法的拾音效果。
在一种可能的实现方式中，激光自混合装置包括发射器和接收器，通过激光自混合装置获取第一电压信号，包括：
控制发射器朝向膜片发出激光；
通过接收器接收由膜片的激光，并形成第一电流信号；
将第一电流信号调制为第一电压信号。
在本实现方式中，激光自混合装置通过朝向膜片发出激光，并接收由膜片反射后形成的激光以形成第一电流信号。其中膜片反射的激光还会与部分背腔中的激光形成自混合干涉效应，进而携带膜片的振动信息，并使得由第一电流信号转换的第一电压信号中也能够携带振动信息。
在一种可能的实现方式中，激光自混合装置包括夸阻放大器和运行放大器，将第一电流信号调制为第一电压信号，包括：
通过夸阻放大器将第一电流信号转换为第一调制电压信号；
通过运行放大器放大第一调制电压信号；
对放大后的第一调制电压信号进行滤波以形成第一电压信号。
在本实现方式中，将第一电流信号转换为第一调制电压信号之后，该第一调制电压信号中包括有高、中、低频的振动信息。因此对第一调制电压信号进行滤波，可以过滤掉不需要的高频和低频振动信息。而对第一调制电压信号进行放大，可以提升第一电压信号的强度，便于后续音频信号的转换。
在一种可能的实现方式中，振膜装置上设有振膜芯片，通过振膜装置获取第二电压信号包括：
通过振膜芯片采集膜片经位移形成的应变信号；
将应变信号转换为第二电压信号。
在本实现方式中，振膜装置通过振膜芯片感应膜片的振动，进而将膜片的位移转换为应变信号，再基于应变信号形成第二电压信号。
在一种可能的实现方式中，将第一电压信号或第二电压信号转换为音频信号，包括：
将第一电压信号或第二电压信号转换为数字信号格式；
对转换为数字信号格式的第一电压信号或第二电压信号进行算法处理以得到音频信号。
在本实现方式中，处理单元获取的第一电压信号和第二电压信号均为模拟信号，在将其处理为音频信号时，需要先对模拟信号进行数字转换，进而得到数字格式的信号并对其进行算法处理。
在一种可能的实现方式中，还包括：
基于第一电压信号形成控制信号，并输出至所述发射器；控制信号用于调节朝向所述膜片发出的激光的波长。
在本实现方式中，对应到外界声音振动的变化，激光自混合装置在采集第一电压信号的过程中，其最佳工作点会相应发生变化。通过计算可以得到激光自混合装置在最佳工作点时所对应的波长。由此对应调整发射器朝向膜片发出的激光波长，可以保证激光自混合装置始终处于最佳工作点进行第一电压信号的采集。
在一种可能的实现方式中，采用锁相算法计算得到激光自混合装置在最佳工作点时所对应的波长。
在一种可能的实现方式中，基于第一电压信号形成控制信号，并输出至发射器以调节朝向膜片发出的激光的波长，包括：
基于第一电压信号计算出激光的最佳工作波长，以形成控制信号；
基于控制信号控制发射器的工作电流大小，以控制朝向膜片发出的激光的波长。
在一种可能的实现方式中，基于第一电压信号计算出激光的最佳工作波长，以形成控制信号，包括：
将模拟格式的第一电压信号转换为数字格式；
基于数字格式的第一电压信号计算出激光的最佳工作波长，以形成控制信号。
在一种可能的实现方式中，基于控制信号控制发射器的工作电流大小，以控制朝向膜片发出的激光的波长，包括：
将数字格式的控制信号转换为模拟格式；
基于模拟格式的控制信号控制发射器的工作电流大小，以控制发射器朝向膜片发出的激光的波长。
在本实现方式中，对激光自混合装置的最佳工作点计算，是基于数字信号格式的第一电压信号来展开的，因此在计算之前，需要对模拟格式的第一电压信号进行数字转换。然后通过例如锁相算法等计算，可以得到激光自混合装置在最佳工作点处的激光的最佳工作波长。然后，通过对发射器工作电流的大小控制，可以控制到激光的波长，以得到调节发射器向膜片发出激光的效果。
在一种可能的实现方式中，激光自混合装置的反馈强度C＜1。
在本实现方式中，控制激光自混合装置的反馈强度C＜1，可以避免接收器所接收到的激光中出现相变或噪声波动，进而保证接收器所接收到的激光质量。
在一种可能的实现方式中，预设阈值为0.1V。
在一种可能的实现方式中，预设阈值为94dB-100dB所对应的音频信号电压值。
在上述两种实现方式中，预设阈值可以设定为0.1V，也可以设置为94dB-100dB所对应的音频信号电压值。激光自混合装置在该预设阈值下，其声音感应能力相对敏感，能准确采集到远距离小声压的声音振动。而在超过该预设阈值之后，激光自混合装置的声音感应能力受噪声影响，相对下降，此时振膜装置可以较好的完成声音采集的工作。
第二方面，本申请提供一种电子设备，电子设备包括麦克风，麦克风采用本申请第一方面提供的声音采集方法拾音。
可以理解的，本申请第二方面提供的电子设备，因为采用了本申请第一方面提供的声音采集方法进行拾音，其同样具备了通过两种不同的方式进行音频信号采集，并通过预设阈值保证音频信号质量的效果。
第三方面，本申请提供一种麦克风，包括基板、防护罩、激光自混合装置、振膜装置以及处理单元；防护罩与处理单元均固定于基板上，防护罩与基板合围形成一内腔，激光自混合装置与振膜装置固定于内腔中，并分别与处理单元通信连接；振膜装置包括膜片和背腔，背腔固定于基板上，膜片位于背腔远离基板一侧，膜片和背腔在基板上合围形成一拾音腔；激光自混合装置包括发射器和接收器，发射器和接收器均收容于拾音腔内，并固定于基板上，发射器用于朝向膜片发射激光，接收器用于接收由膜片反射的激光；基板上还设有多个拾音孔，拾音腔通过多个拾音孔与外界连通。
本申请第二方面提供的麦克风，通过基板和防护罩合围形成了内腔，以收容激光自混合装置和振膜装置，并对二者提供防护。振膜装置通过膜片和背腔，在内腔中进一步与基板合围形成拾音腔。基板上还设有拾音孔，外界声音振动可以通过拾音孔进入到拾音腔中，并引起膜片振动。振膜装置可以将膜片的振动识别并形成第二电压信号。然后，激光自混合装置收容于拾音腔内，通过朝向膜片发射激光，可以接收由膜片和背腔共同反射回的激光，并感应形成第一电压信号。
可以理解的，本申请第三方面提供的麦克风，因为同时设置了激光自混合装置和振膜装置，可以应用并实现上述第一方面的声音采集方法。也即本申请麦克风可以通过激光自混合 装置和振膜装置分别获取第一电压信号和第二电压信号，通过预设阈值的方式进行音频信号的转换，进而使得激光自混合装置与振膜装置相互形成补充，在各自相对理想的工作场景下进行音频信号的采集，保证本申请麦克风的拾音效果。
在一种可能的实现方式中，膜片包括反射单元，反射单元位于膜片朝向基板的表面上，发射器发出的激光经反射单元反射后，由接收器接收。
在本实现方式中，通过在膜片朝向基板的表面上设置反射单元，可以更好的对发射器发出的激光进行反射，进而保证接收器有效的接收到反射的激光。
在一种可能的实现方式中，反射单元位于膜片的几何中心，发射器和接收器在基板上的位置，位于反射单元在基板上的投影区域之内。
在本实现方式中，膜片的几何中心为其振幅最大区域，将反射单元、发射器和接收器均对应膜片的几何中心设置，可以提升反射的激光自混合效率，有利于对振动信息的提取。
在一种可能的实现方式中，反射单元与发射器之间的距离H满足条件：20um≤H≤100um。
在本实现方式中，限定反射单元与发射器之间的距离，可以控制到激光反射的行程，保证激光的自混合效率。
在一种可能的实现方式中，振膜装置包括振膜芯片，振膜芯片用于检测膜片的振动，并形成第二电压信号传输给处理单元。
在本实现方式中，振膜芯片可以将膜片的位移转换为应变信号，并最终形成第二电压信号传输给处理单元。
在一种可能的实现方式中，振膜为压电式振膜或压阻式振膜，振膜芯片为压电式振膜芯片或压阻式振膜芯片。
在本实现方式中，振膜装置可以采用压阻式振膜装置或压电式振膜装置来实现，对应振膜芯片为压阻式振膜芯片或压电式振膜芯片，以实现第二电压信号的可靠采集。
在一种可能的实现方式中，膜片的厚度D满足条件：0.1um≤D≤1um。
在本实现方式中，通过对膜片厚度D的控制，可以保证膜片对外界声音的相应能力。
在一种可能的实现方式中，膜片设有阻挡层，阻挡层位于膜片朝向基板一侧，背腔通过阻挡层与膜片固定连接。
在本实现方式中，阻挡层连接于背腔和膜片的主体之间，可以实现背腔与膜片之间的绝缘，保证振膜芯片可靠感应到膜片的振动并形成第二电压信号。
在一种可能的实现方式中，振膜芯片为压阻式振膜芯片，振膜内设有压阻敏感单元，压阻敏感单元用于感应膜片的振动，并将膜片的位移信号传输给压阻式振膜芯片。
在一种可能的实现方式中，振膜芯片为压电式振膜芯片，膜片本体为压电材料制备，内设有金属层，本体用于感应膜片的振动并产生电荷，金属层对电荷进行收集并通过传输单元将电荷信号传输给压电式振膜芯片。
在上述两种实现方式中，对应到振膜装置的工作原理不同，振膜芯片将接收到的不同信号均转换为第二电压信号，实现对膜片振动的感应。
在一种可能的实现方式中，膜片的残余应力小于或等于50MPa。
在本实现方式中，通过对膜片残余应力的监控，可以控制到膜片的灵敏度。
在一种可能的实现方式中，膜片的材料为硅或含硅化合物。
在本实现方式中，膜片的材料采用硅或含硅化合物，可以保证膜片的机械性能，并利于制造。
在一种可能的实现方式中，膜片上开设有贯穿的平衡孔。
在本实现方式中，膜片上的平衡孔贯穿于拾音腔和内腔之间，内腔中的空气得以先后通过平衡孔和拾音孔与外界连通，保证内腔和拾音腔的压力平衡。
第四方面，本申请提供一种电子设备，电子设备包括上述第三方面所提供的麦克风，用于采集音频信号。
可以理解的，本申请第四方面提供的电子设备，因为包括了本申请第三方面提供的麦克风进行拾音，其同样具备了通过两种不同的方式进行音频信号采集，并通过预设阈值保证音频信号质量的效果。
附图说明
图1是本申请提供的一种电子设备的内部框架示意图；
图2是本申请提供的一种电子设备的结构示意图；
图3是本申请提供的一种麦克风的结构示意图；
图4是本申请提供的一种麦克风的分解结构示意图；
图5是本申请提供的一种麦克风中振膜装置的分解结构示意图；
图6是本申请提供的一种麦克风中内腔的剖面结构示意图；
图7是本申请提供的一种麦克风中拾音腔的平面结构示意图；
图8是本申请提供的一种麦克风中振膜装置的局部剖面结构示意图；
图9是本申请提供的一种麦克风中振膜装置的制作方法步骤示意图；
图10a-图10h分别是本申请提供的一种麦克风中振膜装置制作方法各步骤的结构示意图；
图11是本申请提供的一种麦克风中振膜装置在另一实施例下的局部剖面结构示意图；
图12是本申请提供的一种声音采集方法流程图；
图13是本申请提供的一种麦克风中信号处理的电路图；
图14是本申请提供的一种声音采集方法在另一实施例下的流程图；
图15是本申请提供的一种声音采集方法在另一实施例下的流程图；
图16是本申请提供的一种麦克风中信号处理在另一实施例下的电路图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述，显然，所描述的实施例仅仅是本申请的一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动的前提下所获得的所有其它实施例，都属于本申请保护的范围。
图1为本申请提供的一种电子设备200的内部框架示意图。
在图1的示意中，电子设备200包括控制芯片201、以及本申请提供的麦克风100。麦克风100与控制芯片201电性连接，麦克风100用于感测外界声音振动，并形成音频信号传输给控制芯片201。控制芯片201接麦克风100感测的音频信号之后，可以将音频信号向外发送，以实现电子设备200的远程通话功能。可以理解的，此处的音频信号也可以理解为音频编码，且音频编码可以采用通讯信号的方式向外发送。对应本申请电子设备200可以为手机、平板、笔记本电脑、台式电脑或电视等终端产品。而在另一些实施例中，控制芯片201接麦克风100感测的音频信号之后，还可以解析出音频信号(编码)中所包含的指令等信息，进而响应用户的语音控制操作。对应本申请电子设备200也可以为上述终端产品，或智能家电设备 等。
在图1的示意中，电子设备200还可以包括音频解码单元202、音频放大单元203以及扬声器204，控制芯片201在相对于麦克风100的后端还依次与音频解码单元202、音频放大单元203以及扬声器204电性连接，控制芯片201在接麦克风100感测到的外界声音振动之后，可以将音频信号发送至扬声器204处，音频信号依次经解码和放大之后，通过扬声器204进行播放。由此电子设备200可以通过麦克风100的声音采集，达到与用户语音交互的功能。图2为本申请提供的一种电子设备200的结构示意图。
在图2的示意中，电子设备200内配置了八个麦克风100，各个麦克风100分布于电子设备200的外边缘不同方位处，用于采集从电子设备200的不同方位传来的声音振动。各个麦克风100均与控制芯片201电性连接，用于传输音频信号。在一些实施例中，还可以对八个麦克风100逐一编号，控制芯片201基于不同编号的麦克风100接收到的音频信号，可以判断出当前感测到音频信号的麦克风100在电子设备200中的位置，即判断出当前发出声音振动的音源相对于电子设备200的方位，达到方位识别的功能。
在后续的音频信号处理过程中，电子设备200可以基于判断到的音源相对于电子设备200的方位，选择性的接收该方位区域的麦克风100进行音频信号的采集，实现音频信号采集的指向功能。另一方面，当多个麦克风100分别采集到音频信号并传输给控制芯片201时，控制芯片201还可以将多路音频信号整合为一路，再向外发送或进行语音互动、指令识别等操作，以提升电子设备200对声音振动采集的准确率。在另一些实施例中，电子设备200中的麦克风100数量为分布位置也可以基于实际使用场景任意设置，本申请对此不做特别限定。
图3示意了本申请提供的一种麦克风100的结构示意图。
本申请提供的麦克风100包括基板10和防护罩20。防护罩20包括防护板21和防护壁22，防护壁22围设于防护板21的周缘，且防护壁22还与基板10固定连接，以使得防护罩20整体与基板10固定连接。防护罩20与基板10合围形成一内腔23(参见图6)。
图4示意了麦克风100的分解结构示意图。
麦克风100还包括振膜装置30。振膜装置30收容于防护罩20与基板10合围形成的内腔23中，且振膜装置30与基板10固定连接。在图4的示意中，麦克风100还包括处理单元40，该处理单元可以为专用集成电路(Application Specific Integrated Circuit，ASIC)。处理单元40也固定于基板10上，并同样收容于内腔23中。处理单元40与基板10固定连接，处理单元40还与振膜装置30电性连接。在另一些实施例中，处理单元40还可以位于防护罩20的外部，即处理单元40可以位于内腔23之外。此时处理单元同样与基板10固定连接，并同时与振膜装置30电性连接。
图5示意了振膜装置30的分解结构示意图。
振膜装置30可以为微机电系统(Micro Electrical Mechanical System，MEMS)，其包括膜片31和背腔32。膜片31为薄膜状，其材料可以采用硅或含硅化合物，或一些实施例中还可以采用压电材料。背腔32呈中空的环状，其内设有贯穿的通孔321。图5的示意中背腔32为圆形，对应通孔321也设置为圆形，使得背腔32呈中空的圆环形状。而在另一些实施例中，背腔32还可以为矩形、椭圆形等结构，对应通孔321的形状也与背腔32的形状匹配设置，以使得背腔32呈矩形环状或椭圆形环状。
膜片31固定于背腔32的一侧，并遮蔽通孔321。背腔32远离膜片31的一侧与基板10固定连接，由此振膜装置30与基板10合围形成一拾音腔33(请配合参见图6示意的麦克风100中内腔23的剖面结构)。可以理解的，拾音腔33收容于内腔23之内。基板10在对应拾音腔33的区 域内开设有至少一个拾音孔11。具体的，请参见图7，背腔32的通孔321在基板10上的投影形成一收容区322，多个拾音孔11均位于收容区322之内。该至少一个拾音孔11贯穿基板10，由此实现了拾音腔33与外部的连通。外部声音振动可以通过各个拾音孔11进入到拾音腔33中，并引发膜片31发生振动。振膜装置30可以将膜片31的位移应变转换为电信号，实现对外部声音振动的采集和捕捉，并形成音频信号传输给处理单元40。
对于本申请麦克风100，其拾音孔11的形状、大小和数量并不做特别的限定。在图7的示意中，拾音孔11的数量为4个，在其余实施例中，拾音孔11的数量也可以为其它数值。且拾音孔11的形状和大小都可以任意设置，只要能连通于拾音腔33和外部空间之间，都可以达到容许外部声音振动从拾音孔11进入到拾音腔33内的效果。
图8示意了振膜装置30内部的一种实现方式。在本实现方式中，膜片31采用压阻式振膜实现。具体的，膜片31包括本体311、反射单元312、阻挡层313、压阻敏感单元314、传输单元315、以及保护层316。其中本体311的材料为硅或含硅化合物。本体311为薄膜状，其具有相背的第一平面311a和第二平面311b。其中第一平面311a为本体311朝向基板10的一侧的外表面，第二平面311b为本体311背离基板10的一侧外表面。从第一平面311a至第二平面311b的方向即为本体311的厚度方向，平行于第一平面311a和第二平面311b的方向则为本体311的平面方向。
阻挡层313连接于本体311与背腔32之间，也即阻挡层313位于第一平面311a上，其用于实现膜片31与背腔32的固定连接，并使得膜片31与背腔32之间整体绝缘。反射单元312也位于第一平面上，且在图8的示意中，反射单元312还设置于本体311的几何中心位置。反射单元312朝向拾音腔33的内部设置。保护层316位于第二平面311b一侧，保护层316朝向拾音腔33的外部设置。保护层316用于对本体311以及膜片31的其余组成结构形成防护。
在本体311的厚度方向上，压阻敏感单元314和传输单元315位于反射单元312和保护层316之间。其中压阻敏感单元314还沿本体311的平面方向分布设置。压阻敏感单元314用于感应本体311所产生的振动位移。当外部声音振动从拾音孔11传入拾音腔33之后，本体311受外界声音振动的激励产生振动位移，压阻敏感单元314随本体311的振动位移产生应变信号，并经其连通的传输单元315向后端传递。进一步的，膜片31还对应压阻敏感单元314设置了压阻式振膜芯片341。压阻式振膜芯片341可以设置于振膜装置30上，也可以集成于处理单元40内。压阻式振膜芯片341与压阻敏感单元314电性连接，用于将压阻敏感单元314感应到的应变信号转换为一路电压信号(具体为第二电压信号V2)，并将该电压信号传输至处理单元40处。
可以理解的，当压阻式振膜芯片341设置于振膜装置30上，具体为设置于膜片31的第二平面311b上时，其可以直接通过传输单元315与压阻敏感单元314电性导通，并实现对应变信号的收集；而当压阻式振膜芯片341集成于处理单元40内时，其需要通过传输线319与传输单元315的配合，再与压阻敏感单元314导通。上述两种压阻式振膜芯片341的设置方式，均可以实现压阻式振膜芯片341与压阻敏感单元314的导通，并使得压阻式振膜芯片341收集到应变信号。
对于本实施例的膜片31，其整体厚度可以介于0.1um至1um之间，例如取值0.9um，以保证其对外界声音振动的声压响应能力和位移灵敏性。膜片31的面积介于0.3mm 2至4mm 2之间，例如1mm 2，此时膜片31的单边边长越小，其覆盖的高频范围越大，而单边边长越长，其灵敏度相对较高，具体可以基于实际使用场景调整。膜片31的残余应力不超过50MPa，以保证膜片31的灵敏度。
而对于反射单元312，其形状可以为圆形，且反射单元312的半径介于10um至1000um之间，例如取值60um，以获得较大的反射面积。反射单元312的厚度可以介于10nm至200nm之间，以保证对光线的反射能力。进一步，反射单元312的几何中心相对于本体311的几何中心偏移需要控制在10um之内。
压阻敏感单元314的厚度可以介于100nm至500nm之间，例如180nm，以形成预设的电阻值，实现对应变信号的采集。
保护层316的厚度则介于50nm至1000nm之间，例如200nm，以保证防护效果。
在一种实施例中，膜片31中还设有平衡孔317。平衡孔317沿膜片31的厚度方向贯穿膜片31，平衡孔317连通于拾音腔33和内腔23之间。当外部声音振动从拾音孔11进入拾音腔33之后，会引起拾音腔33内的空气压力变化，造成膜片31在拾音腔33和内腔23之间形成压力差，可能对膜片31的振动形成干扰。平衡孔317的开设，可以平衡拾音腔33与内腔23之间的压力，进而保证膜片31的振动效果。平衡孔317的孔径可以介于0.5um至5um之间，例如1.5um。
对于压阻式振膜芯片341设置于膜片31上的实施例，还需要对压阻式振膜芯片341的结构进行限定，以避免压阻式振膜芯片341影响到膜片31的振动效果。在一种实施例中，压阻式振膜芯片341的形状为矩形，其边长组合可以介于0.5×0.5mm至5×5mm之间，例如1.4×1.4mm。压阻式振膜芯片341的厚度可以介于150um至500um之间，例如220um。
请参见图9和图10a-图10h所分别示意的，本申请振膜装置30的制作方法步骤。本申请振膜装置30可以通过如下步骤展开并得到：
S101、提供一硅基底，并在硅基底上通过热氧化工艺形成两层热氧化层313a和313b(见图10a)；
其中，一层热氧化层313a位于硅基底的一侧外表面上，另一热氧化层313b位于硅基底的内部，并与外表面上的热氧化层313a相互间隔。
S102、通过轻硼掺杂工艺在硅基底中制作压阻敏感单元314(见图10b)；
其中，压阻敏感单元314位于两层热氧化层313a和313b之间，且在制作压阻敏感单元314的过程中同步对其进行图案化。
S103、通过浓硼掺杂工艺在硅基底中制作部分传输单元315a(见图10c)；
其中，该部分传输单元315a在硅基底中的深度与压阻敏感单元314的深度平齐，以使得该部分传输单元315a分别连通各个图案化的压阻敏感单元314。
S104、对位于硅基底外表面上的热氧化层313a进行刻蚀，以露出S103步骤中制作的传输单元315a结构(见图10d)；
其中，热氧化层313a经刻蚀后形成膜片31的保护层316，保护层316中具有刻蚀形成的过孔315b。
S105、通过沉积工艺在过孔315b中和保护层316的外表面上填充金属，以形成另一部分传输单元315c(见图10e)；
其中，在保护层316上的金属形成位于保护层316之外的可导电结构层，该部分金属通过过孔315b中填充的金属与步骤S103中制作的部分传输单元315a导通，进而步骤S105中制作的部分传输单元315c和步骤S103中制作的另一部分传输单元315a共同组成传输单元315，达到将压阻敏感单元314中的应变信号引至保护层316外部的效果。后续，传输单元315可以直接连通至压阻式振膜芯片341，或通过传输线319连通至振膜芯片341。
在一些实施例中，该步骤还可以完成平衡孔317的制作。
S106、通过深反应离子刻蚀工艺在硅基底的另一侧外表面上刻蚀，以去除硅基底的材料 至露出另一热氧化层313b(见图10f)；
其中，该部分硅基底的刻蚀为中心刻蚀，保留有硅基底外围的材料以形成振膜装置30的背腔32。而另一热氧化层313b与保护层316之间的硅基底材料则形成为膜片31的本体311。
S107、通过漂洗工艺去除步骤S106中露出的部分热氧化层313b(见图10g)；
其中，漂洗工艺后剩余的热氧化层313b则形成为膜片31的阻挡层313，其连接于本体311与背腔32之间。同时热氧化层313b被部分去除后，也露出了本体311的第一平面311a。该漂洗工艺可以采用氢氟酸(Hydrofluoric acid，HF)试剂进行漂洗。
S108、通过蒸镀工艺在第一平面311a上制作反射单元312(见图10h)。
其中，反射单元312可以采用铝或含铝合金制备。
由此，本申请实施例提供的振膜装置30可以完成制作，并保证各个组件和层结构之间的位置和功能实现。
图11则示意了振膜装置30另一种实现方式的结构。在图11的实现方式中，膜片31采用压电式膜片实现。具体的，膜片31也包括本体311、反射单元312、阻挡层313、传输单元315、以及保护层316。本体311为压电材料制备，整体也呈薄膜状，其具有相背的第一平面311a和第二平面311b。其中第一平面311a为本体311朝向基板10的一侧的外表面，第二平面311b为本体311背离基板10的一侧外表面。阻挡层313连接于本体311与背腔32之间，反射单元312也位于第一平面311a上，保护层316位于第二平面311b一侧，用于对本体311以及膜片31的其余组成结构形成防护。
在本实施例中，于本体311的厚度方向上，则设置有金属层318和传输单元315，位于本体311的第一平面311a和第二平面311b之间。其中金属层318的数量可以为一层或多层，图11中示意为两层。传输单元315分别与各层金属层318电性导通，且传输单元315还部分伸出第二平面311b。在本实施例中，保护层316还位于传输单元315背离反射单元312一侧，用于覆盖并保护伸出第二平面311b的传输单元315。
当外部声音振动从拾音孔11传入拾音腔33之后，本体311受外界声音振动的激励产生振动位移。采用压电材料制备的本体311自身会形成电荷。设于本体311内的金属层318实现对电荷的收集，并形成电荷信号经其连通的传输单元315向后端传递。进一步的，膜片31还对应设置了压电式振膜芯片342。压电式振膜芯片342可以设置于振膜装置30上，也可以集成于处理单元40内。压电式振膜芯片342与传输单元315电性连接，用于将金属层318收集到的电荷信号转换为第二电压信号V2，并将该第二电压信号V2传输至处理单元40处。
可以理解的，对于图11所示采用压电式振膜实现的振膜装置30，其内部如本体311、反射单元312、保护层316以及压电式振膜芯片342等尺寸限定、以及平衡孔317的实施例等，都可以参照上述压阻式的振膜装置30设置，以提升振膜装置30的灵敏度。由此，本申请振膜装置30采用上述压阻式或压电式的实施例，也都能够实现对外界声音振动的可靠采集。
请看回图5、图6和图7，本申请麦克风100还包括激光自混合装置60。激光自混合装置60收容于拾音腔33之内，其包括有发射器61和接收器62。发射器61和接收器62均相对于基板10固定，其中发射器61可以采用垂直腔面发射激光器(Vertical Cavity Surface Emitting Laser，VCSEL)，用于朝向反射单元312发射激光，接收器62则用于接收经反射单元312反射回的激光。其中，发射器61发出的激光、以及经反射单元312反射的激光，均会在拾音腔33中形成衍射，该部分衍射的激光还照射至膜片31的第一平面311a以及背腔32的内壁上，并经反射后部分被接收器62接收。进一步的，膜片31的振动也会造成部分激光被反射至背腔32的内壁上。当外界声音振动引发膜片31发生振动时，上述经反射单元312反射的激光会携带膜 片31的振动信息。该部分激光会与经背腔32的内壁反射的激光混合，在拾音腔33中形成自混合效应。自混合后的激光束的强度和频率会发生改变，该强度和频率的改变也携带有膜片31的振动信息。接收器62接收该混合后的激光信号之后，可以将发射器61发出的激光与混合后的激光进行比较，提取到电流信号(具体为第一电流信号A1)并将其转换为电压信号(具体为第一电压信号V1)传输给处理单元40。
在图6和图7的示意中，发射器61和接收器62还重叠设置，发射器61固定于基板10上，接收器62位于发射器61背离基板10一侧。进一步的，膜片31平行于基板10设置，其第一平面311a同时垂直于发射器61和接收器62。由此，反射单元312也垂直于发射器61和接收器62设置。且发射器61和接收器62在基板10上的位置，位于反射单元312在基板10上的投影范围之内。此时发射器61沿垂直于基板10的方向朝向膜片31发射激光，激光经反射单元312垂直反射后，被接收器62接收，可以减短激光在拾音腔33中的飞行距离。
对于本申请麦克风100，拾音腔33可以定义为麦克风100的前腔，膜片31相对于基板10的距离则定义为前腔高度。除拾音腔33之外的内腔23的空间则定义为麦克风100的后腔。膜片31相对于防护板21的内表面的高度则定义为后腔高度。在一种实施例中，限定反射单元312与发射器61之间的距离H满足条件：20um≤H≤100um。该限定控制了发射器61与膜片31之间的距离，并因为限定了发射器61与膜片31之间的距离，而控制了激光在拾音腔33中的飞行距离，进而减小接收器62所获取激光信号的信噪比(Signal to Noise Ratio，SNR)。
而因为发射器61固定于基板10上，控制发射器61与反射单元312之间的距离，也同步控制了基板10与膜片31之间的距离。即通过上述限定，控制了麦克风100的前腔高度。在内腔23的空间高度一定的前提下，控制麦克风100的前腔高度即增大了麦克风100的后腔高度，更大的后腔高度也有利于提升振膜装置30的信噪比。进一步的，在上述膜片31的实施例中，本体311都只采用了一层或者两层的层结构，麦克风100即可达到较好的工作状态，相较于现有技术中设置多层层结构的膜片而言，本申请中膜片31的厚度更薄，相应获得的后腔空间也更大，有利于提升振膜装置30的信噪比。
由此，本申请麦克风100除可以通过振膜装置30采集外界声音振动之外，还可以通过激光自混合装置60采集外界声音振动。两种声音振动的采集方式可以相互补充，或采用融合算法等方式，以保证麦克风100能达到更好的声音采集效果。而采用本申请麦克风100的电子设备200，也因为麦克风100所具备的更好的声音采集效果，而提升了其音频采集能力。
请参见图12所示，本申请提供的一种声音采集方法，本方法包括如下步骤：
S100、通过激光自混合装置60获取第一电压信号V1，并同时通过振膜装置30获取第二电压信号V2；
S200、若第一电压信号V1低于或等于预设阈值V0，则将第一电压信号V1转换为音频信号；若第一电压信号V1高于预设阈值V0，则将第二电压信号V2转换为音频信号。
可以理解的，本申请声音采集方法，基于上述同时包括激光自混合装置60和振膜装置30的麦克风100展开。具体的，在步骤S100的过程中，当发生外界声音振动时，声波从拾音孔11传入拾音腔33中，并引起膜片31的振动。此时振膜装置30自身可以感应到膜片31的振动，并采用压电或压阻的方式对膜片31的位移进行感应，形成第二电压信号V2传输给处理单元40；而激光自混合装置60也同时对膜片31的振动进行监测，并形成第一电压信号V1传输给处理单元40。此时，处理单元40所获取到的两路电压信号均是基于同一外界声音振动所形成的，也即激光自混合装置60和振膜装置30所采集的声音振动为同一环境中的声音振动、第一电压信号V1和第二电压信号V2均用于反映该同一环境中的声音振动。
处理单元40在分别获取到第一电压信号V1和第二电压信号V2之后，会基于预设的阈值V0来判断第一电压信号V1的数值大小。即处理单元40会对第一电压信号V1和预设阈值V0进行比较，并基于比较结果对第一电压信号V1或第二电压信号V2进行处理。具体的，当第一电压信号V1低于或等于预设阈值V0时，处理单元40选择第一电压信号V1并行进处理，将其转换为向后端输出的音频信号；而当第一电压信号V1高于预设阈值V0时，处理单元40则选择第二电压信号V2进行处理，将其转换为向后端输出的音频信号。
出于激光自混合装置60与振膜装置30各自采集声音的原理不同，两种装置在声音采集方面也各具优势。其中激光自混合装置60相对灵敏度更高，其可以用于采集声音振动能量相对较小、声压较低的声音振动信号；但在声音振动能量较大、高声压的场景下，激光自混合装置60的噪声升高，信噪比降低，同时其声学过载点(Acoustic Overload Point，AOP)也相对偏低，对声音的整体识别能力下降。而振膜装置30则对声压较高的场景具有更好的识别能力，且能够控制到信号的信噪比，同时具备更高的声学过载点。
外界声音振动的能量可以通过声压的大小来进行识别。反应到本申请麦克风100中，则可以通过采集得到的第一电压信号V1的数值大小，或通过采集得到的第二电压信号V2的数值大小来进行识别区分。本申请声音采集方法可以通过预设阈值V0的设置，来控制麦克风100在相对较低声压的场景中，采用激光自混合装置60进行声音振动的采集，以提升麦克风100的灵敏度，拓宽麦克风100的工作范围；而在相对较高声压的场景中，本申请麦克风100则采用振膜装置30进行声音振动的采集，以保证信号的信噪比，和提升麦克风100的声学过载点。
进一步的，因为第一电压信号V1和第二电压信号V2均用于反应同一环境中的声音振动，因此二者在时间上可以视为同步。当处理单元40由对第一电压信号V1切换至对第二电压信号V2进行处理，或处理单元由对第二电压信号V2切换至对第一电压信号V1进行处理时，因为两路信号的时间同步特性而不会产生信号失步或丢帧的现象，进而保证麦克风100能够持续对外界声音振动进行采集，并转换得到连续的音频信号。
另一方面，基于振膜装置30中膜片31和背腔32的结构不同，以及激光自混合装置60中发射器61和接收器62的选型差异，本申请声音采集方法中对于预设阈值V0的设定，也并非为唯一值。在一些实施例中，预设阈值V0可以设置为0.1V，即激光自混合装置60所采集到的第一电压信号V1的数值低于或等于0.1V时，处理单元40则将第一电压信号V1处理为音频信号；当第一电压信号V1的数值高于0.1V时，处理单元40则将第二电压信号V2处理为音频信号。而在另一些实施例中，还可以将预设阈值定义为激光自混合装置60在采集94dB-100dB所对应的音频信号时所形成的电压值，也可以保证到激光自混合装置60和振膜装置30各自在其更理想的工作(即声压)场景下对声音振动进行采集。
可以理解的，在上述实施例中，预设阈值V0可以为某一数值点，也可以为某一数值范围。因为振膜装置30和激光自混合装置60各自的理想工作场景可能存在部分重叠的区域，也即在该重叠区域(即声压大小的范围)内，振膜装置30和激光自混合装置60均能实现较好的声音振动采集效果。
在一些实施例中，将预设阈值V0设置为范围值后，还可以对处理单元40的信号切换方式进行一定的设置。例如当处理单元40正基于第一电压信号V1进行音频信号的转换时，若第一电压信号V1未超过预设阈值V0的上限，则可以控制处理单元40持续基于第一电压信号V1进行音频信号的转换，以保证音频信号的连续性；而当处理单元40正基于第二电压信号V2进行音频信号的转换时，若第一电压信号V1未低于预设阈值V0的下限，则可以控制处理单元40持续 基于第二电压信号V2进行音频信号的转换，也可以保证音频信号的连续性。同时，本实施例的方法也避免了处理单元40频繁切换其处理信号线路而可能造成的信号失步或丢帧现象。
在一种实施例中，对于步骤S100中的“通过激光自混合装置60获取第一电压信号V1”，可以包括如下子步骤：
S110、控制发射器61朝向膜片31发出激光；
S120、通过接收器62接收由膜片31反射的激光，并形成第一电流信号A1；
S130、将第一电流信号A1调制为第一电压信号V1。
前述中提到，激光自混合装置60的接收器62在接收到反射的激光之后，其感应产生的信号为电流信号(即第一电流信号A1)。而本申请方法的预设阈值V0为电压信号，因此需要先将第一电流信号A1进行调制，使之转换为第一电压信号V1之后，处理单元40才能将第一电压信号V1与预设阈值V0进行比较判断。而在一些实施例中，接收器62所接收到的激光信号还可以为拾音腔33内经自混合形成的激光束。
进一步的，在一种实施例中，步骤S130“将第一电流信号A1调制为第一电压信号V1”，还包括如下子步骤：
S131、通过夸阻放大器将第一电流信号A1转换为第一调制电压信号VT1；
S132、通过运行放大器放大第一调制电压信号VT1；
S133、对放大后的第一调制电压信号VT1进行滤波以形成第一电压信号V1。
具体请配合参见图13。图13示意了本申请麦克风100中信号处理的电路图。在本实施例中，激光自混合装置60内部还设有夸阻放大器63、运行放大器64、低通滤波器65、和高通滤波器66。其中夸阻放大器63与接收器62电性连通，夸阻放大器63用于将第一电流信号A1转换为第一调制电压信号VT1；运行放大器64与夸阻放大器63电性连通，运行放大器64用于放大第一调制电压信号VT1，以提升第一调制电压信号VT1的强度，使放大后的第一调制电压信号VT1能匹配到处理单元40的数据处理需求；低通滤波器65和高通滤波器66先后于运行放大器64连通，用于分别对放大后的第一调制电压信号VT1进行低通滤波和高通滤波，形成第一电压信号V1。
因为人耳能接收到的音频范围有限，而第一调制电压信号VT1中携带的部分振动信息经转换为音频信号之后，超出了人耳的音频接收范围。因此对放大后的第一调制电压信号VT1进行滤波后，能够筛除部分人耳音频接收范围之外的振动信息，放大后的第一调制电压信号VT1经滤波后形成的第一电压信号V1仅保留了位于人耳音频接收范围之内的振动信息，可以减少处理单元40的工作负荷。
而对于振膜装置30，在一种实施例中，步骤S100中的“通过振膜装置30获取第二电压信号V2”，可以包括如下子步骤：
S140、通过振膜芯片采集膜片31经位移形成的应变信号；
S150、将应变信号转换为第二电压信号V2。
基于上述关于振膜装置30的方案描述，本申请振膜装置30在采集外界声音振动的过程中，需要通过振膜芯片感应膜片31的振动，进而将膜片31的位移转换为应变信号，再基于应变信号形成第二电压信号V2。其中，振膜芯片可以为压阻式振膜芯片341，也可以为压电式振膜芯片342。当振膜芯片为压电式振膜芯片342时，其应变信号具体为电荷信号，即采集到的压电材料的本体311在振动中因形变所产生的电荷，再将电荷信号转换为第二电压信号V2。
需要提出的是，对于上述子步骤S110至S130中，关于激光自混合装置60工作形成第一电 压信号V1的工作流程，以及上述子步骤S140至S150中，关于振膜装置30工作形成第二电压信号V2的工作流程，属于两路不同的处理电路分别工作，并同步运行所完成的操作。上述序号的先后顺序并不代表麦克风100具体工作流程的顺序，二者实际为并行的关系。具体可以参见图14的本申请声音采集方法另一流程示意图。
在一种实施例中，基于图13和图14的示意，本申请在步骤S200“将第一电压信号V1或第二电压信号V2转换为音频信号”时，还可以包括如下子步骤：
S210、将第一电压信号V1或第二电压信号V2转换为数字信号格式；
S220、对转换为数字信号格式的第一电压信号V1或第二电压信号V2进行算法处理以得到音频信号。
具体的，在本实施例中，处理单元40包括转换模块41和处理模块42。从激光自混合装置60输入的第一电压信号V1为模拟信号格式，从振膜装置30输入的第二电压信号V2也为模拟信号的格式。而在处理模块42对第一电压信号V1或第二电压信号V2进行处理时，需要先通过转换模块41将第一电压信号V1和第二电压信号V2进行数字转换，使其从模拟信号转换为数字信号之后，转换模块41再将数字信号格式的第一电压信号V1和第二电压信号V2传输给处理模块42，并由处理模块42将其处理为音频信号。
请参见图15所示的本申请声音采集方法另一实施例的流程图，并同步参见图16所示的对应该流程图的电路图。在步骤S100“通过激光自混合装置60获取第一电压信号V1”之后，本方法还可以包括：
S300、基于第一电压信号V1形成控制信号，并输出至发射器61以调节朝向膜片31发出的激光的波长。
具体的，对应到外界声音振动的变化，激光自混合装置60在采集第一电压信号V1的过程中，其最佳工作点(或描述为激光的最佳工作强度和频率)也会相应发生变化。基于第一电压信号V1的数值不同，处理单元40可以通过如锁相算法等方式计算得到激光自混合装置60当前的最佳工作点。此时处理单元40可以同步解析出激光自混合装置60在最佳工作点工作时所发出的激光波长。通过处理单元40对发射器61的工作电流控制，可以控制到激光自混合装置60发出的激光的波长，进而保证激光自混合装置60始终处于最佳工作点进行第一电压信号V1的采集。
在一种实施例中，步骤S300“基于第一电压信号V1采用锁相算法以调节发射器61朝向膜片31发出的激光的波长”，还可以包括如下子步骤：
S310、基于第一电压信号V1计算出激光的最佳工作波长，以形成控制信号；
S320、基于控制信号控制发射器61的工作电流大小，以控制朝向膜片31发出的激光的波长。
具体的，对于步骤S310还可以包括如下子步骤：
S311、将模拟格式的第一电压信号V1转换为数字格式；
S312、基于数字格式的第一电压信号V1计算出激光的最佳工作波长，以形成控制信号；
而对于步骤S320，则可以包括如下子步骤：
S321、将数字格式的控制信号转换为模拟格式；
S322、基于模拟格式的控制信号控制发射器61的工作电流大小，以控制发射器61朝向膜片31发出的激光波长。
具体的，前述中提到，处理单元40包括处理模块42。对激光自混合装置60的最佳工作点计算，是处理模块42基于数字信号格式的第一电压信号V1来展开的。因此在计算得到激光的 最佳工作波长之前，还需要转换模块41对模拟格式的第一电压信号V1进行数字格式转换。处理模块42在计算完成之后还需要将计算结果传回至转换模块41，并通过转换模块41将数字格式的计算结果转换为模拟信号格式的模拟控制信号。然后，发射器61接该模拟控制信号并控制工作电流的大小，达到控制其发出的激光波长的目的。
其中，在图15中，上述步骤S310“将模拟格式的第一电压信号V1转换为数字格式”可以通过S210“将第一电压信号V1或第二电压信号V2转换为数字信号格式”来实现。
在一种实施例中，本申请方法还可以包括：
设置激光自混合装置60的反馈强度C＜1。
具体的，在本实施例中，激光自混合装置60的反馈强度，可以理解为发射器61发出的激光，在拾音腔中经自混合后，结合传播媒介增益、光损耗以及相位叠加之后，相对于初始发出的激光的强度和频率变化。反馈强度与麦克风100前腔高度、反射单元312的反射率、激光器线宽、激光的频率以及激光自混合装置60的谐振腔高度等相关。当反馈强度C＞1时，接收器62所接收到的光信号会发生相位改变，并伴随有高相噪；当反馈强度C＝1时，应变信号的相跳和相噪相应变小；而当反馈强度C＜1时，接收器62接收到的光信号中不会出现相位跳动，且相噪也相对较低。因此，通过本实施例对激光自混合装置60反馈强度的控制，可以保证接收器62所接收到的激光信号的质量。
以上描述，仅为本申请的具体实施例，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，例如减少或添加结构件，改变结构件的形状等，都应涵盖在本申请的保护范围之内；在不冲突的情况下，本申请的实施例及实施例中的特征可以相互组合。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (16)

  1. 一种声音采集方法，用于麦克风，其特征在于，所述麦克风包括激光自混合装置和振膜装置，其中所述振膜装置包括膜片，所述膜片用于响应声音振动，所述激光自混合装置和所述振膜装置分别用于检测所述膜片的振动；
    所述方法包括：
    通过所述激光自混合装置获取第一电压信号，并同时通过所述振膜装置获取第二电压信号；
    若所述第一电压信号低于或等于预设阈值，则将所述第一电压信号转换为音频信号；若所述第一电压信号高于所述预设阈值，则将所述第二电压信号转换为音频信号。
  2. 根据权利要求1所述的声音采集方法，其特征在于，所述激光自混合装置包括发射器和接收器，所述通过所述激光自混合装置获取第一电压信号，包括：
    控制所述发射器朝向所述膜片发出激光；
    通过所述接收器接收由所述膜片反射的激光，并形成第一电流信号；
    将所述第一电流信号调制为所述第一电压信号。
  3. 根据权利要求2所述的声音采集方法，其特征在于，所述激光自混合装置还包括夸阻放大器和运行放大器；
    所述将第一电流信号调制为第一电压信号，包括：
    通过夸阻放大器将所述第一电流信号转换为第一调制电压信号；
    通过运行放大器放大所述第一调制电压信号；
    对放大后的所述第一调制电压信号进行滤波以形成所述第一电压信号。
  4. 根据权利要求1-3任一项所述的声音采集方法，其特征在于，所述振膜装置包括振膜芯片，所述通过所述振膜装置获取第二电压信号，包括：
    通过所述振膜芯片采集所述膜片经位移形成的应变信号；
    将所述应变信号转换为所述第二电压信号。
  5. 根据权利要求1-4任一项所述的声音采集方法，其特征在于，还包括：
    基于所述第一电压信号形成控制信号，并输出至所述发射器；所述控制信号用于调节朝向所述膜片发出的激光的波长。
  6. 根据权利要求5所述的声音采集方法，其特征在于，所述基于所述第一电压信号形成控制信号，并输出至所述发射器以调节朝向所述膜片发出的激光的波长，包括：
    基于所述第一电压信号计算出激光的最佳工作波长，以形成所述控制信号；
    基于所述控制信号控制所述发射器的工作电流大小，以控制朝向所述膜片发出的激光的波长。
  7. 根据权利要求1-6任一项所述的声音采集方法，其特征在于，所述激光自混合装置的反馈强度C＜1。
  8. 一种电子设备，其特征在于，所述电子设备包括麦克风，所述麦克风采用如权利要求1-7任一项所述声音采集方法拾音。
  9. 一种麦克风，其特征在于，包括基板、防护罩、激光自混合装置、振膜装置以及处理单元；
    所述防护罩与所述处理单元均固定于所述基板上，所述防护罩与所述基板合围形成一内腔，所述激光自混合装置与所述振膜装置固定于所述内腔中，并分别与所述处理单元通信连接；
    所述振膜装置包括膜片和背腔，所述背腔固定于所述基板上，所述膜片位于所述背腔远离所述基板一侧，所述膜片和所述背腔在所述基板上合围形成一拾音腔；
    所述激光自混合装置包括发射器和接收器，所述发射器和所述接收器均收容于所述拾音腔内，并固定于所述基板上，所述发射器用于朝向所述膜片发射激光，所述接收器用于接收由所述膜片反射的激光；
    所述基板上还设有多个拾音孔，所述拾音腔通过所述多个拾音孔与外界连通。
  10. 根据权利要求9所述的麦克风，其特征在于，所述膜片包括反射单元，所述反射单元位于所述膜片朝向所述基板的表面上，所述发射器发出的激光经所述反射单元反射后，由所述接收器接收。
  11. 根据权利要求10所述的麦克风，其特征在于，所述反射单元位于所述膜片的几何中心，所述发射器和所述接收器在所述基板上的位置，位于所述反射单元在所述基板上的投影区域之内。
  12. 根据权利要求9-11任一项所述的麦克风，其特征在于，所述振膜装置包括振膜芯片，所述振膜芯片用于检测所述膜片的振动，并形成第二电压信号传输给所述处理单元。
  13. 根据权利要求12所述的麦克风，其特征在于，所述膜片为压电式膜片或压阻式膜片，对应所述振膜芯片为压电式振膜芯片或压阻式振膜芯片。
  14. 根据权利要求9-13任一项所述的麦克风，其特征在于，所述膜片的厚度D满足条件：0.1um≤D≤1um。
  15. 根据权利要求9-14任一项所述的麦克风，其特征在于，所述反射单元与所述发射器之间的距离H满足条件：20um≤H≤100um。
  16. 一种电子设备，其特征在于，包括如权利要求8-14任一项所述的麦克风，所述麦克风用于采集音频信号。
PCT/CN2022/126904 2021-10-29 2022-10-24 声音采集方法、麦克风和电子设备 WO2023071960A1 (zh)

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