Sound acquisition methods, microphones, and electronic devices

Abstract

The present application provides a sound capturing method applied to a microphone. The microphone comprises a laser magnetic mixing device and a diaphragm device, wherein the diaphragm device comprises a membrane configured to respond to sound vibrations, and the laser magnetic mixing device and the diaphragm device are configured separately to detect vibrations of the membrane. In this method, a first voltage signal is acquired using the laser magnetic mixing device, and a second voltage signal is simultaneously acquired using the diaphragm device. If the first voltage signal is below a preset threshold, the first voltage signal is converted into an audio signal; or if the first voltage signal is greater than the preset threshold, the second voltage signal is converted into an audio signal. According to the method of the present application, the audio signal can be collected in two different ways, so that a transition between the two signals is implemented using a preset threshold, and the more matching signal is selected and converted into an audio signal. This can ensure the quality of the audio signal. The present application further relates to a microphone and an electronic device.

Description

Technology Field

[0001] This application claims priority to Chinese patent application No. 202111276854.9, filed with the China National Intellectual Property Administration on October 29, 2021, with the title of the invention "SOUND CAPTURING METHOD, MICROPHONE, AND ELECTRONIC DEVICE", the entirety of which is incorporated herein by reference.

[0002] Technology field

[0003] The present application relates to the field of electronic devices, and specifically to a sound capturing method, a microphone, and an electronic device using the sound capturing method or including the microphone. Background Technology

[0004] There are multiple scenarios in which electronic devices use microphones for sound pickup, such as telephone calls, video calls, voice assistants, teleconference, mass live streaming, and online teaching, all of which require microphones to extract audio signals. The signal-to-noise ratio of conventional microphones generally does not exceed 70 dB. However, as usage requirements continue to rise, some scenarios require the microphone's signal-to-noise ratio to increase to 80 dB or higher. Consequently, it is difficult for conventional microphones to meet these performance requirements.

[0005] The present application provides a sound capturing method for improving the sound pickup signal-to-noise ratio of a microphone. The present application further relates to a microphone and an electronic device. Specifically, the following technical solutions are included.

[0006] According to a first aspect, the present application provides a sound capturing method applied to a microphone, wherein the microphone comprises a laser self-mixing apparatus and a diaphragm apparatus, the diaphragm apparatus comprises a membrane, the membrane is configured to respond to sound vibrations, and the laser self-mixing apparatus and the diaphragm apparatus are configured separately to detect vibrations of the membrane. The method comprises:

[0007] A step of acquiring a first voltage signal using a laser magnetic mixing device and simultaneously acquiring a second voltage signal using a diaphragm device; and

[0008] The method includes the step of converting the first voltage signal into an audio signal if the first voltage signal is below a preset threshold; or the step of converting the second voltage signal into an audio signal if the first voltage signal is greater than a preset threshold.

[0009] The sound capturing method in the present application corresponds to a microphone comprising both a laser magnetic mixing device and a diaphragm device. A first voltage signal can be acquired using a laser magnetic mixing device, and a second voltage signal can be acquired using a diaphragm device. The first voltage signal and the second voltage signal are signals acquired by the laser magnetic mixing device and the diaphragm device, respectively, based on the response of the membrane to external sound vibrations. Next, the first voltage signal is compared with a preset threshold value to select whether to convert the first voltage signal into an audio signal or to convert the second voltage signal into an audio signal.

[0010] The laser magnetic mixing device is relatively sensitive to the detection of sound vibrations and can respond to sound vibrations with low sound pressure. Consequently, the response range and signal-to-noise ratio of the sound capturing method of the present application are increased. Additionally, the acoustic overload point of the diaphragm device is relatively high. When the diaphragm device is used in a scenario of vibration with relatively high sound pressure, a better sound capturing effect can be provided. Thus, according to the sound capturing method, a preset threshold is set so that the laser magnetic mixing device and the diaphragm device can complement each other and collect audio signals in their respective relatively desirable operating scenarios, thereby ensuring the sound pickup effect of the sound capturing method of the present application.

[0011] In a possible implementation, the laser magnetic mixing device includes a transmitter and a receiver, and obtaining a first voltage signal using the laser magnetic mixing device is:

[0012] Controlling the transmitter to emit laser light toward the membrane;

[0013] Using a receiver to receive laser light from a membrane and form a first current signal; and

[0014] It includes modulating a first current signal into a first voltage signal.

[0015] In this implementation, a laser self-mixing device emits laser light toward a membrane and receives the laser light formed through reflection performed by the membrane to form a first current signal. The laser light reflected by the membrane further forms a self-mixing interference effect with a portion of the laser light in the back cavity, so that vibration information of the membrane can be carried, and the first voltage signal to which the first current signal is converted can also carry vibration information.

[0016] In a possible implementation, the laser magnetic mixing device includes a transimpedance amplifier and an operational amplifier; modulating the first current signal into a first voltage signal is:

[0017] Converting a first current signal into a first modulated voltage signal using a transimpedance amplifier;

[0018] Amplifying a first modulation voltage signal using an operational amplifier; and

[0019] It includes forming a first voltage signal by performing filtering on an amplified first modulated voltage signal.

[0020] In this implementation, after the first current signal is converted into a first modulated voltage signal, the first modulated voltage signal includes high-frequency, intermediate-frequency, and low-frequency vibration information. Accordingly, filtering is performed on the first modulated voltage signal so that unnecessary high-frequency and low-frequency vibration information can be filtered out. Additionally, the first modulated voltage signal can be amplified so that the strength of the first voltage signal is increased. This facilitates the subsequent conversion of the audio signal.

[0021] In a possible implementation, the diaphragm device is provided with a diaphragm chip, and obtaining a second voltage signal using the diaphragm device is:

[0022] Collecting strain signals formed by the displacement of a membrane using a diaphragm chip; and

[0023] It includes converting the strain signal into a second voltage signal.

[0024] In this implementation, the diaphragm device uses a diaphragm chip to detect vibration of the membrane, then converts the displacement of the membrane into a strain signal, and forms a second voltage signal based on the strain signal.

[0025] In a possible implementation, converting the first voltage signal or the second voltage signal into an audio signal is:

[0026] Converting a first voltage signal or a second voltage signal into a digital signal format; and

[0027] It includes performing algorithm processing on a first voltage signal or a second voltage signal converted into a digital signal format to obtain an audio signal.

[0028] In this implementation, the first voltage signal and the second voltage signal obtained by the processing unit are each analog signals. While processing the first voltage signal or the second voltage signal into an audio signal, it is necessary to first perform digital conversion on the analog signal to obtain a signal in a digital format and perform algorithm processing on the signal in the digital format.

[0029] In a possible implementation, the method is:

[0030] The method further includes the step of forming a control signal based on a first voltage signal and outputting the control signal to a transmitter, wherein the control signal is used to adjust the wavelength of laser light emitted toward the membrane.

[0031] In this implementation, external sound vibrations change, and in response, the optimal operating point of the laser magnetic mixing device may change during the process of collecting the first voltage signal. The wavelength corresponding to the optimal operating point of the laser magnetic mixing device can be obtained through calculation. Accordingly, the wavelength of the laser light emitted toward the membrane by the transmitter is adjusted in response, ensuring that the laser magnetic mixing device always collects the first voltage signal at the optimal operating point.

[0032] In a possible implementation, the wavelength corresponding to the optimal operating point of the laser magnetic mixing device is obtained through calculations based on a phase-locked loop algorithm.

[0033] In a possible implementation, forming a control signal based on a first voltage signal and outputting the control signal to a transmitter to adjust the wavelength of laser light emitted toward the membrane is:

[0034] Obtaining the optimal operating wavelength of the laser light through calculations based on the first voltage signal and forming a control signal; and

[0035] It includes controlling the magnitude of the operating current of the transmitter based on a control signal to control the wavelength of the laser light emitted toward the membrane.

[0036] In a possible implementation, obtaining the optimal operating wavelength of the laser light through calculations based on the first voltage signal and forming a control signal is:

[0037] Converting a first voltage signal from an analog format to a digital format; and

[0038] It includes obtaining the optimal operating wavelength of the laser light through calculations based on a first voltage signal in a digital format and forming a control signal.

[0039] In a possible implementation, controlling the wavelength of the laser light emitted toward the membrane by controlling the magnitude of the transmitter's operating current based on a control signal is:

[0040] Converting a control signal from a digital format to an analog format; and

[0041] It includes controlling the magnitude of the operating current of the transmitter based on a control signal of an analog format to control the wavelength of the laser light emitted toward the membrane by the transmitter.

[0042] In this implementation, the optimal operating point of the laser magnetic mixing device is calculated based on a first voltage signal in a digital signal format. Therefore, prior to the calculation, digital conversion must be performed on the first voltage signal in an analog format. Subsequently, the optimal operating wavelength of the laser light of the laser magnetic mixing device at the optimal operating point can be obtained through calculations based on a phase-locked loop algorithm, etc. Next, the wavelength of the laser light is controlled by controlling the magnitude of the operating current of the transmitter, thereby adjusting the laser light emitted to the membrane by the transmitter.

[0043] In a possible implementation, the feedback strength C of the laser magnetic mixing device is less than 1.

[0044] In this implementation, the feedback strength C of the laser magnetic mixing device is controlled to be less than 1. This can avoid phase changes or noise fluctuations of the laser light received by the receiver, thereby ensuring the quality of the laser light received by the receiver.

[0045] In a possible implementation, the preset threshold is 0.1V.

[0046] In a possible implementation, the preset threshold is a voltage value of the audio signal corresponding to 94dB to 100dB.

[0047] In the two aforementioned implementations, the preset threshold can be set to 0.1V or to a voltage value of an audio signal corresponding to 94dB to 100dB. When the first voltage signal is equal to the preset threshold, the sound detection capability of the laser magnetic mixer is relatively sensitive, and the laser magnetic mixer can accurately capture distant sound vibrations with low sound pressure. When the first voltage signal is greater than the preset threshold, the sound detection capability of the laser magnetic mixer is degraded due to the influence of noise. In this case, the diaphragm device can complete sound capturing better.

[0048] According to a second aspect, the present application provides an electronic device, wherein the electronic device includes a microphone, and the microphone performs sound pickup using a sound capturing method according to a first aspect of the present application.

[0049] Since the electronic device according to the second aspect of the present application performs sound pickup using the sound capturing method according to the first aspect of the present application, it can be understood that the electronic device also collects audio signals in two different ways and ensures the quality of the audio signal using a preset threshold.

[0050] According to a third aspect, the present application provides a microphone comprising a substrate, a protective cover, a laser magnetic mixing device, a diaphragm device, and a processing unit. Both the protective cover and the processing unit are fixed to the substrate, and the protective cover and the substrate form an internal cavity through an enclosure, and the laser magnetic mixing device and the diaphragm device are fixed to the internal cavity and each is communicably connected to the processing unit. The diaphragm device includes a membrane and a back cavity, the back cavity is fixed to the substrate, the membrane is located on the side of the back cavity away from the substrate, and the membrane and the back cavity form a sound pickup cavity through an enclosure on the substrate. The laser magnetic mixing device includes a transmitter and a receiver, both of which are housed in the sound pickup cavity and fixed to the substrate, and the transmitter is configured to emit laser light toward the membrane, and the receiver is configured to receive laser light reflected by the membrane. The circuit board is additionally provided with a plurality of sound pickup holes, and the sound pickup cavity communicates with the outside through the plurality of sound pickup holes.

[0051] In a microphone according to a second aspect of the present application, a protective cover and a substrate form an internal cavity through an enclosure to accommodate a laser magnetic mixing device and a diaphragm device, and to protect the laser magnetic mixing device and the diaphragm device. The diaphragm device further forms a sound pickup cavity in the internal cavity through the enclosure with the substrate using a membrane and a back cavity. The substrate is further provided with a sound pickup hole. External sound vibrations can enter the sound pickup cavity through the sound pickup hole and cause the membrane to vibrate. The diaphragm device can detect the vibration of the membrane and form a second voltage signal. Next, the laser magnetic mixing device is accommodated within the sound pickup cavity. By emitting laser light toward the membrane, the laser magnetic mixing device receives the laser light that is reflected back together by the membrane and the back cavity and can form a first voltage signal through detection.

[0052] Since both the laser magnetic mixing device and the diaphragm device are disposed in the microphone according to the third embodiment of the present application, it can be understood that the sound capturing method according to the first embodiment can be applied to the microphone according to the third embodiment of the present application and implemented thereby. Specifically, the microphone in the present application can acquire a first voltage signal and a second voltage signal using the laser magnetic mixing device and the diaphragm device, respectively, and convert an audio signal using a preset threshold value, so that the laser magnetic mixing device and the diaphragm device can complement each other and collect audio signals in their respective relatively preferred operating scenarios, thereby ensuring the sound pickup effect of the microphone in the present application.

[0053] In a possible implementation, the membrane includes a reflective unit, the reflective unit is located on the surface of the membrane facing the substrate, and laser light emitted by a transmitter is received by a receiver after being reflected by the reflective unit.

[0054] In this implementation, the reflection unit is placed on the surface of the membrane facing the substrate, so that the laser light emitted by the transmitter can be reflected better, ensuring that the receiver effectively receives the reflected laser light.

[0055] In a possible implementation, the reflector unit is located at the geometric center of the membrane, and the transmitter and receiver on the substrate are located within the projection area of ​​the reflector unit on the substrate.

[0056] In this implementation, the geometric center of the membrane is the region of the membrane with the largest amplitude. Since the reflector, transmitter, and receiver are all positioned corresponding to the geometric center of the membrane, the magnetic mixing efficiency of the reflected laser light can be improved. This helps to extract vibration information.

[0057] In a possible implementation, the distance H between the reflector unit and the transmitter satisfies the condition: 20 µm ≤ H ≤ 100 µm.

[0058] In this implementation, since the distance between the reflection unit and the transmitter is limited, the reflection path of the laser light can be controlled, and the magnetic mixing efficiency of the laser light can be guaranteed.

[0059] In a possible implementation, the diaphragm device includes a diaphragm chip, and the diaphragm chip is configured to detect vibration of the membrane, form a second voltage signal, and transmit the second voltage signal to a processing unit.

[0060] In this implementation, the diaphragm chip can convert the displacement of the membrane into a strain signal and finally form a second voltage signal and transmit the second voltage signal to a processing unit.

[0061] In a possible implementation, the membrane is a piezoelectric diaphragm or a piezoresistive diaphragm, and the diaphragm chip is a piezoelectric diaphragm chip or a piezoresistive diaphragm chip.

[0062] In this implementation, the diaphragm device may be implemented by a piezoresistive diaphragm device or a piezoelectric diaphragm device, and the diaphragm chip is correspondingly a piezoresistive diaphragm chip or a piezoelectric diaphragm chip, thereby enabling reliable acquisition of the second voltage signal.

[0063] In a possible implementation, the thickness D of the membrane satisfies the condition: 0.1 µm ≤ D ≤ 1 µm.

[0064] In this implementation, since the thickness D of the membrane is controlled, the corresponding ability of the membrane for external sound can be ensured.

[0065] In a possible implementation, the membrane is provided with a barrier layer, the barrier layer is located on the side of the membrane facing the substrate, and the back cavity is fixed to the membrane through the barrier layer.

[0066] In this implementation, the barrier layer is connected between the back cavity and the body of the membrane, so that insulation between the back cavity and the membrane can be achieved, and it can be ensured that the diaphragm chip reliably detects vibrations of the membrane and forms a second voltage signal.

[0067] In a possible implementation, the diaphragm chip is a piezoresistive diaphragm chip, a piezoresistive sensitive unit is placed on the diaphragm, and the piezoresistive sensitive unit is configured to detect vibrations of the membrane and transmit a displacement signal of the membrane to the piezoresistive diaphragm chip.

[0068] In a possible implementation, the diaphragm chip is a piezoelectric diaphragm chip, the body of the membrane is made of a piezoelectric material, and a metal layer is disposed on the body of the membrane. The body is configured to detect vibrations of the diaphragm and generate an electric charge. The metal layer collects the electric charge and transmits a charge signal to the piezoelectric diaphragm chip using a transmitting unit.

[0069] In the two aforementioned implementations, the operating principles of the diaphragm device are different, and accordingly, the diaphragm chip converts all received different signals into a second voltage signal to detect vibration of the membrane.

[0070] In a possible implementation, the residual stress of the membrane is 50 MPa or less.

[0071] In this implementation, since the residual stress of the membrane is monitored, the sensitivity of the membrane can be controlled.

[0072] In a possible implementation, the membrane is made of silicon or a silicon-containing compound.

[0073] In this implementation, the membrane is made of silicon or a silicon-containing compound, so the mechanical performance of the membrane can be ensured and manufacturing becomes easy.

[0074] In a possible implementation, the membrane is provided with a penetrating balancing hole.

[0075] In this implementation, the balancing hole on the membrane penetrates between the sound pickup cavity and the inner cavity, so that the air in the inner cavity can sequentially communicate with the outside through the balancing hole and the sound pickup hole. This ensures pressure balance between the inner cavity and the sound pickup cavity.

[0076] According to a fourth aspect, the present application provides an electronic device, wherein the electronic device includes a microphone according to a third aspect, and the microphone is configured to collect an audio signal.

[0077] Since the electronic device according to the fourth aspect of the present application includes a microphone according to the third aspect of the present application for sound pickup, it can be understood that the electronic device also collects audio signals in two different ways and ensures the quality of the audio signal using a preset threshold. Brief explanation of the drawing

[0078] FIG. 1 is a schematic diagram of the internal framework of an electronic device according to the present application. FIG. 2 is a schematic diagram of the structure of an electronic device according to the present application. FIG. 3 is a schematic diagram of the structure of a microphone according to the present application. FIG. 4 is a schematic exploded view of the structure of a microphone according to the present application. FIG. 5 is a schematic exploded view of the structure of a diaphragm device of a microphone according to the present application. FIG. 6 is a schematic cross-sectional view of the structure of the internal cavity of a microphone according to the present application. FIG. 7 is a schematic plan view of the structure of a sound pickup cavity of a microphone according to the present application. FIG. 8 is a schematic cross-sectional view of a partial structure of a diaphragm device of a microphone according to the present application. FIG. 9 is a schematic diagram of the steps of a method for manufacturing a diaphragm device in a microphone according to the present application. FIGS. 10a to 10h are each schematic diagrams of the structure for each step of the method for manufacturing a diaphragm device in a microphone according to the present application. FIG. 11 is a schematic cross-sectional view of another embodiment of a partial structure of a diaphragm device of a microphone according to the present application. FIG. 12 is a flowchart of a sound capturing method according to the present application. FIG. 13 is a circuit diagram of signal processing in a microphone according to the present application. FIG. 14 is a flowchart of another embodiment of the sound capturing method according to the present application. FIG. 15 is a flowchart of another embodiment of the sound capturing method according to the present application. FIG. 16 is a circuit diagram of another embodiment of signal processing in a microphone according to the present application. Specific details for implementing the invention

[0079] The following describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings. It is evident that the described embodiments are only a part, not all, of the embodiments of the present application. All other embodiments obtained by a person skilled in the art based on the embodiments of the present application without creative effort will fall within the scope of protection of the present application.

[0080] FIG. 1 is a schematic diagram of the internal framework of an electronic device (200) according to the present application.

[0081] As illustrated in FIG. 1, the electronic device (200) includes a control chip (201) and a microphone (100) provided in the present application. The microphone (100) is electrically connected to the control chip (201), and the microphone (100) is configured to detect external sound vibrations, form an audio signal, and transmit the audio signal to the control chip (201). After receiving the audio signal detected by the microphone (100), the control chip (201) can transmit the audio signal externally to implement a remote calling function of the electronic device (200). It may also be understood that the audio signal in this specification can be understood as an audio code, and that the audio code can be transmitted externally in the form of a communication signal. The electronic device (200) according to the present application may be a terminal product such as a mobile phone, tablet, notebook computer, desktop computer, or television. In some other embodiments, after receiving an audio signal detected by the microphone (100), the control chip (201) may further analyze information such as instructions included in the audio signal (code) to respond to a user's voice control action. The electronic device (200) according to the present application may alternatively be the aforementioned terminal product, smart home appliance, etc.

[0082] As illustrated in FIG. 1, the electronic device (200) may further include an audio decoding unit (202), an audio amplification unit (203), and a speaker (204). A control chip (201) is located at the back end of the microphone (100) and is further electrically connected sequentially to the audio decoding unit (202), the audio amplification unit (203), and the speaker (204). After receiving external sound vibrations detected by the microphone (100), the control chip (201) can transmit an audio signal to the speaker (204). The audio signal is sequentially decoded and amplified, and then played back through the speaker (204). In this way, the electronic device (200) can implement the function of voice interaction with a user through sound capturing by the microphone (100). FIG. 2 is a schematic diagram of the structure of the electronic device (200) according to the present application.

[0083] As illustrated in FIG. 2, eight microphones (100) are placed on an electronic device (200). The microphones (100) are distributed in different orientations on the outer edges of the electronic device (200) and are configured to capture sound vibrations from the different orientations of the electronic device (200). Each microphone (100) is electrically connected to a control chip (201) and configured to transmit an audio signal. In some embodiments, the eight microphones (100) may be additionally numbered one by one. The control chip (201) can determine the position of the microphone (100) in the electronic device (200) currently detecting the audio signal based on audio signals received from the microphones (100) having different numbers, that is, can implement the function of orientation identification by determining the orientation of the electronic device (200) of the sound source currently emitting sound vibrations.

[0084] In a subsequent audio signal processing process, the electronic device (200) may selectively receive audio signals captured by the microphone (100) in the area of ​​the corresponding orientation based on the determined orientation of the sound source to the electronic device (200), thereby implementing a directional function for audio signal collection. Additionally, when a plurality of microphones (100) each collect audio signals and transmit the audio signals to the control chip (201), the control chip (201) may further integrate the plurality of audio signals into a single signal and then transmit the signal externally or perform operations such as voice interaction or command identification to improve the accuracy of sound vibration capturing by the electronic device (200). In some other embodiments, the distribution and quantity of microphones (100) in the electronic device (200) may alternatively be specified as required based on actual usage scenarios. This is not particularly limited in the present application.

[0085] FIG. 3 is a schematic diagram of the structure of a microphone (100) according to the present application.

[0086] The microphone (100) provided in the present application includes a substrate (10) and a protective cover (20). The protective cover (20) includes a protective plate (21) and protective walls (22). The protective walls (22) are positioned around the edges of the protective plate (21), and since the protective walls (22) are further fixed to the substrate (10), the entire protective cover (20) is fixed to the substrate (10). The protective cover (20) and the substrate (10) form an internal cavity (23) (see FIG. 6) through an enclosure.

[0087] Figure 4 is a schematic exploded view of the structure of the microphone (100).

[0088] The microphone (100) further includes a diaphragm device (30). The diaphragm device (30) is housed in an internal cavity (23) formed through an enclosure by a protective cover (20) and a substrate (10), and the diaphragm device (30) is fixed to the substrate (10). As illustrated in FIG. 4, the microphone (100) further includes a processing unit (40), and the processing unit may be an Application-Specific Integrated Circuit (ASIC). The processing unit (40) is also fixed to the substrate (10) and is also housed in the internal cavity (23). The processing unit (40) is fixed to the substrate (10), and the processing unit (40) is additionally electrically connected to the diaphragm device (30). In some other embodiments, the processing unit (40) may alternatively be located outside the protective cover (20). In other words, the processing unit (40) can be located outside the internal cavity (23). In this case, the processing unit is still fixed to the substrate (10) and electrically connected to the diaphragm device (30).

[0089] FIG. 5 is a schematic exploded view of the structure of the diaphragm device (30).

[0090] The diaphragm device (30) may be a Micro Electrical Mechanical System (MEMS) and includes a membrane (31) and a back cavity (32). In some embodiments, the membrane (31) is in the form of a thin film, and the membrane (31) may be made of silicon or a silicon-containing compound or a piezoelectric material. The back cavity (32) is in the form of a hollow ring and is provided with a penetrating through hole (321). As shown in FIG. 5, the back cavity (32) is circular, and correspondingly, the through hole (321) is designated as circular, so that the back cavity (32) is in the form of a hollow circular ring. In some other embodiments, the back cavity (32) may alternatively be rectangular, elliptical, etc., and correspondingly, the through hole (321) is specified to have a shape that matches the shape of the back cavity (32), so that the back cavity (32) has the shape of a rectangular ring or an elliptical ring.

[0091] The membrane (31) is fixed to the side of the back cavity (32) and shields the through hole (321). Since the side of the back cavity (32) away from the membrane (31) is fixed to the substrate (10), the diaphragm device (30) and the substrate (10) form a sound pickup cavity (33) through the enclosure (refer to the cross-sectional view of the structure of the internal cavity (23) of the microphone (100) shown in FIG. 6). It can be understood that the sound pickup cavity (33) is accommodated in the internal cavity (23). At least one sound pickup hole (11) is provided in the area of ​​the substrate (10) corresponding to the sound pickup cavity (33). Specifically, as illustrated in FIG. 7, the protrusion 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 all located in the receiving area (322). At least one sound pickup hole (11) penetrates the substrate (10) to enable 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 membrane (31) to vibrate. The diaphragm device (30) can convert the displacement strain of the membrane (31) into an electrical signal to collect and capture external sound vibrations, form an audio signal, and transmit the audio signal to a processing unit (40).

[0092] The shapes, sizes, and quantity of the sound pickup holes (11) of the microphone (100) according to the present application are not particularly limited. As shown in FIG. 7, there may be four sound pickup holes (11). In other embodiments, there may alternatively be a different number of sound pickup holes (11). Additionally, the shape and size of the sound pickup holes (11) may be specified as needed. If the sound pickup holes (11) can communicate with the sound pickup cavity (33) and the external space, external sound vibrations are allowed to enter the sound pickup cavity (33) through the sound pickup holes (11).

[0093] FIG. 8 illustrates an internal implementation of a diaphragm device (30). In this implementation, the membrane (31) is implemented by a piezoresistive diaphragm. Specifically, the membrane (31) comprises a body (311), a reflective unit (312), a barrier layer (313), piezoresistive sensitive units (314), transmitting units (315), and a protective layer (316). The body (311) is made of silicon or a silicon-containing compound. The body (311) is in the form of a thin film, and the body (311) has a first plane (311a) and a second plane (311b) facing each other. The first plane (311a) is the outer surface of the side of the body (311) facing the substrate (10). The second plane (311b) is the outer surface of the side of the body (311) away from the substrate (10). The direction from the first plane (311a) to the second plane (311b) is the thickness direction of the main body (311). The direction parallel to the first plane (311a) and the second plane (311b) is the planar direction of the main body (311).

[0094] A barrier layer (313) is connected between the main body (311) and the back cavity (32). That is, the barrier layer (313) is located on the first plane (311a). The barrier layer (313) is configured to fix the membrane (31) to the back cavity (32) and completely insulate the membrane (31) from the back cavity (32). A reflective unit (312) is also located on the first plane. As shown in FIG. 8, the reflective unit (312) is further positioned at the geometric center of the main body (311). The reflective unit (312) faces the interior of the sound pickup cavity (33). A protective layer (316) is located on the side of the second plane (311b), and the protective layer (316) faces the exterior of the sound pickup cavity (33). The protective layer (316) is configured to protect the remaining structural components of the main body (311) and the membrane (31).

[0095] In the thickness direction of the main body (311), the piezoresistive sensitive units (314) and the transmitting units (315) are located between the reflective unit (312) and the protective layer (316). The piezoresistive sensitive units (314) are further distributed in the planar direction of the main body (311). The piezoresistive sensitive units (314) are configured to detect vibration displacement generated by the main body (311). After external sound vibrations are transmitted to the sound pickup cavity (33) through the sound pickup hole (11), the main body (311) is excited by the external sound vibrations and generates vibration displacement. The piezoresistive sensitive units (314) generate strain signals from the vibration displacement of the main body (311) and transmit the strain signals in the reverse direction through the transmitting units (315) connected to the piezoresistive sensitive units (314). Additionally, the membrane (31) is provided with a piezoresistive diaphragm chip (341) corresponding to the piezoresistive sensitive units (314). The piezoresistive diaphragm chip (341) may be placed on the diaphragm device (30) or integrated within the processing unit (40). The piezoresistive diaphragm chip (341) is electrically connected to the piezoresistive sensitive unit (314) and is configured to convert strain signals detected by the piezoresistive sensitive unit (314) into a voltage signal (specifically, a second voltage signal (V2)) and transmit the voltage signal to the processing unit (40).

[0096] It can be understood that when a piezoresistive diaphragm chip (341) is placed on a diaphragm device (30), specifically on a second plane (311b) of a membrane (31), the piezoresistive diaphragm chip (341) can be electrically connected directly to piezoresistive sensitive units (314) through transmitting units (315) and strain signals can be collected. When the piezoresistive diaphragm chip (341) is integrated into a processing unit (40), the piezoresistive diaphragm chip (341) needs to be mated between the transmitting units (315) and the transmitting line (319) and connected to the piezoresistive sensitive units (314). Both of the above-described methods of arranging the piezoresistive diaphragm chip (341) can implement a connection between the piezoresistive diaphragm chip (341) and the piezoresistive sensitive units (314), and can allow the piezoresistive diaphragm chip (341) to collect strain signals.

[0097] In this embodiment, the total thickness of the membrane (31) may be in the range of 0.1 µm to 1 µm, and, for example, may have a value of 0.9 µm, thereby ensuring the ability of the membrane (31) to respond to the sound pressure of external sound vibrations and the displacement sensitivity of the membrane (31). The area of ​​the membrane (31) is 0.3 mm 2 up to 4mm 2 It is the range, for example, 1mm 2 In this case, a shorter side length of the membrane (31) indicates that the higher frequency range covered by the membrane (31) is greater, and a longer side length indicates that the sensitivity of the membrane (31) is relatively higher. This can be specifically adjusted based on actual application scenarios. Since the residual stress of the membrane (31) does not exceed 50 MPa, the sensitivity of the membrane (31) is guaranteed.

[0098] The shape of the reflection unit (312) may be circular, and the radius of the reflection unit (312) is in the range of 10 µm to 1000 µm, and for example, has a value of 60 µm, so a relatively large reflection area is obtained. The thickness of the reflection unit (312) may be in the range of 10 nm to 200 nm, so light reflection capability is ensured. In addition, the distance between the geometric center of the reflection unit (312) and the geometric center of the main body (311) needs to be controlled to within 10 µm.

[0099] In order to reach a preset resistance value so that a strain signal is collected, the thickness of the piezoresistive sensitive unit (314) may be in the range of 100 nm to 500 nm, for example, 180 nm.

[0100] The thickness of the protective layer (316) is in the range of 50 nm to 1000 nm, for example, 200 nm, to ensure a protective effect.

[0101] In one embodiment, the membrane (31) is additionally provided with a balancing hole (317). The balancing hole (317) penetrates the membrane (31) in the thickness direction of the membrane (31) and communicates with the sound pickup cavity (33) and the inner cavity (23). After external sound vibrations enter the sound pickup cavity (33) through the sound pickup hole (11), the atmospheric pressure in the sound pickup cavity (33) may change. Consequently, the membrane (31) forms a pressure difference between the sound pickup cavity (33) and the inner cavity (23), which may cause interference with the vibration of the membrane (31). The balancing hole (317) is provided to ensure the vibration effect of the membrane (31) by balancing the pressure within the sound pickup cavity (33) and the inner cavity (23). The diameter of the balancing hole (317) may be in the range of 0.5 µm to 5 µm, for example, 1.5 µm.

[0102] In an embodiment in which a piezoresistive diaphragm chip (341) is placed on a membrane (31), the structure of the piezoresistive diaphragm chip (341) needs to be further restricted to prevent the piezoresistive diaphragm chip (341) from affecting the vibration effect of the membrane (31). In one embodiment, the shape of the piezoresistive diaphragm chip (341) is rectangular, and the combination of the side lengths of the piezoresistive diaphragm chip (341) may be in the range of 0.5 mm x 0.5 mm to 5 mm x 5 mm, for example, 1.4 mm x 1.4 mm. The thickness of the piezoresistive diaphragm chip (341) may be in the range of 150 µm to 500 µm, for example, 220 µm.

[0103] FIGS. 9 and FIGS. 10a through 10h illustrate steps of a method for manufacturing a diaphragm device (30) according to the present application. The diaphragm device (30) according to the present application can be expanded and obtained through the following steps.

[0104] S101: Provide a silicon substrate and form two thermal oxide layers (313a and 313b) on the silicon substrate through a thermal oxidation process (see FIG. 10a).

[0105] One thermal oxide layer (313a) is located on the outer surface of one side of the silicon substrate, and another thermal oxide layer (313b) is located inside the silicon substrate and is spaced apart from the thermal oxide layer (313a) on the outer surface.

[0106] S102: A piezoresistive sensitive unit (314) is fabricated on a silicon substrate through a light boron doping process (see FIG. 10b).

[0107] The piezoresistive sensitive unit (314) is located between two thermal oxide layers (313a and 313b) and is patterned synchronously in the process of manufacturing the piezoresistive sensitive unit (314).

[0108] S103: A portion of the transmitting unit (315a) is manufactured on a silicon substrate through a high-concentration boron doping process (see FIG. 10c).

[0109] The depth of a portion of the transmitting unit (315a) in the silicon substrate is the same as the depth of the piezoresistive sensitive unit (314) in the silicon substrate, so that the portion of the transmitting unit (315a) communicates with each patterned piezoresistive sensitive unit (314).

[0110] S104: Etching the thermal oxide layer (313a) located on the outer surface of the silicon substrate to expose the structure of the transmitting unit (315a) manufactured in step S103 (see FIG. 10d).

[0111] The thermal oxide layer (313a) is etched to form a protective layer (316) of the membrane (31), and the protective layer (316) has vias (315b) formed through etching.

[0112] S105: The outer surface of the via (315b) and the protective layer (316) is filled with metal through a deposition process to form another part of the transmitting unit (315c) (see FIG. 10e).

[0113] The metal on the protective layer (316) forms a conductive structural layer outside the protective layer (316). The metal is connected to a part of the transmitting unit (315a) manufactured in step S103 through the metal filled in the via (315b), so that a part of the transmitting unit (315c) manufactured in step S105 and another part of the transmitting unit (315a) manufactured in step S103 together form the transmitting unit (315). In this way, the strain signal of the piezoresistive sensitive unit (314) is induced outside the protective layer (316). Subsequently, the transmitting unit (315) can be directly connected to the piezoresistive diaphragm chip (341) or connected to the diaphragm chip (341) through the transmitting line (319).

[0114] In some embodiments, the manufacturing of the balancing hole (317) may be further completed at this stage.

[0115] S106: The outer surface of the other side of the silicon substrate is etched through a deep reactive ion etching process to remove the material of the silicon substrate until another thermal oxide layer (313b) is exposed (see FIG. 10f).

[0116] The etching of this part of the silicon substrate is central etching, and the material of the peripheral part of the silicon substrate is retained to form the back cavity (32) of the diaphragm device (30). The material of the silicon substrate between the other thermal oxide layer (313b) and the protective layer (316) forms the body (311) of the membrane (31).

[0117] S107: Through a rinsing process, a portion of the thermal oxide layer (313b) exposed in step S106 is removed (see FIG. 10g).

[0118] The thermal oxide layer (313b) remaining after the rinsing process forms a barrier layer (313) of the membrane (31), and the barrier layer (313) is connected between the main body (311) and the back cavity (32). Additionally, after the thermal oxide layer (313b) is partially removed, the first plane (311a) of the main body (311) is also exposed. The rinsing process can be performed using a hydrofluoric acid (HF) reagent.

[0119] S108: A reflection unit (312) is manufactured on a first plane (311a) through a deposition process (see FIG. 10h).

[0120] The reflection unit (312) may be made of aluminum or an aluminum alloy.

[0121] In this way, the diaphragm device (30) provided in this embodiment of the present application can be manufactured, and the locations of each component and each layer structure and the implementation of the functions of each component and each layer structure are ensured.

[0122] FIG. 11 illustrates a different embodiment of the structure of a diaphragm device (30). In the embodiment of FIG. 11, the membrane (31) is implemented by a piezoelectric membrane. Specifically, the membrane (31) also includes a body (311), a reflective unit (312), a barrier layer (313), transmitting units (315), and a protective layer (316). The body (311) is made of a piezoelectric material. The entire body (311) is also in the shape of a thin film, and the body (311) has a first plane (311a) and a second plane (311b) facing each other. The first plane (311a) is the outer surface of the side of the body (311) facing the substrate (10). The second plane (311b) is the outer surface of the side of the body (311) away from the substrate (10). A barrier layer (313) is connected between the main body (311) and the back cavity (32). A reflective unit (312) is also located on the first plane (311a). A protective layer (316) is located on the side of the second plane (311b) and is configured to protect the remaining structural components of the main body (311) and the membrane (31).

[0123] In this embodiment, the metal layers (318) and the transmitting units (315) are arranged in the thickness direction of the main body (311) and are located between the first plane (311a) and the second plane (311b) of the main body (311). There may be one or more metal layers (318). FIG. 11 illustrates two metal layers (318). The transmitting units (315) are each electrically connected to the metal layers (318), and the transmitting units (315) partially extend further out of the second plane (311b). In this embodiment, a protective layer (316) is further located on one side of the transmitting unit (315) facing away from the reflective unit (312) and is configured to cover and protect the transmitting units (315) extending out of the second plane (311b).

[0124] After external sound vibrations are transmitted to the sound pickup cavity (33) through the sound pickup hole (11), the main body (311) is excited by the external sound vibrations and generates vibrational displacement. The main body (311), made of a piezoelectric material, can form an electric charge. A metal layer (318) disposed on the main body (311) collects the electric charge, forms a charge signal, and transmits the charge signal in the reverse direction through a transmitting unit (315) connected to the metal layer (318). Additionally, a piezoelectric diaphragm chip (342) is provided in the membrane (31) in correspondence. The piezoelectric diaphragm chip (342) may be disposed on the diaphragm device (30) or integrated within the processing unit (40). The piezoelectric diaphragm chip (342) is electrically connected to the transmitting unit (315) and is configured to convert the charge signal collected by the metal layer (318) into a second voltage signal (V2) and transmit the second voltage signal (V2) to the processing unit (40).

[0125] It can be understood that, in order to improve the sensitivity of the diaphragm device (30), the dimensions of the main body (311), the reflection unit (312), the protective layer (316), the piezoelectric diaphragm chip (342), etc., inside the diaphragm device (30) implemented by the piezoelectric diaphragm shown in FIG. 11, and embodiments of the balancing hole (317), etc., can all be specified by reference to the aforementioned piezoresistive diaphragm device (30). Accordingly, embodiments of the diaphragm device (30) according to the present application implemented by a piezoresistive membrane or a piezoelectric membrane can also achieve reliable capturing of external sound vibrations.

[0126] Refer to FIGS. 5, FIGS. 6, and FIGS. 7. The microphone (100) according to the present application further comprises a laser magnetic mixing device (60). The laser magnetic mixing device (60) is housed in a sound pickup cavity (33) and includes a transmitter (61) and a receiver (62). Both the transmitter (61) and the receiver (62) are fixed to a substrate (10). The transmitter (61) may be a VCSEL (Vertical-Cavity Surface-Emitting Laser) and is configured to emit laser light toward a reflection unit (312). The receiver (62) is configured to receive laser light reflected by the reflection unit (312). Both the laser light emitted by the transmitter (61) and the laser light reflected by the reflection unit (312) may be diffracted in the sound pickup cavity (33). The diffracted laser light strikes the first plane (311a) of the membrane (31) and the inner wall of the back cavity (32), and is partially received by the receiver (62) after reflection. Additionally, vibrations of the membrane (31) also cause a portion of the laser light to be reflected to the inner wall of the back cavity (32). When external sound vibrations cause vibrations of the membrane (31), the aforementioned laser light reflected by the reflection unit (312) can carry vibration information of the membrane (31). The laser light can be mixed with the laser light reflected by the inner wall of the back cavity (32) to form a self-mixing effect in the sound pickup cavity (33). The intensity and frequency of the self-mixing laser light beam can be varied, and the varied intensity and varied frequency also carry vibration information of the membrane (31). After receiving the laser signal obtained through mixing, the receiver (62) can compare the laser light emitted by the transmitter (61) with the laser light obtained through mixing, extract a current signal (specifically, a first current signal (A1)), convert the current signal into a voltage signal (specifically, a first voltage signal (V1)), and transmit the voltage signal to the processing unit (40).

[0127] As illustrated in FIGS. 6 and 7, the transmitter (61) and receiver (62) are additionally arranged in an overlapping manner, the transmitter (61) is fixed to the substrate (10), and the receiver (62) is positioned on the side of the transmitter (61) facing away from the substrate (10). Additionally, the membrane (31) is arranged parallel to the substrate (10), and the first plane (311a) of the membrane (31) is perpendicular to both the transmitter (61) and the receiver (62). Thus, the reflection unit (312) is also arranged perpendicular to the transmitter (61) and the receiver (62). Furthermore, the transmitter (61) and the receiver (62) on the substrate (10) are located within the projection range of the reflection unit (312) on the substrate (10). In this case, the transmitter (61) emits a laser light toward the membrane (31) in a direction perpendicular to the substrate (10), and the laser light is reflected perpendicularly by the reflection unit (312) and then received by the receiver (62), so that the flight distance of the laser light in the sound pickup cavity (33) can be shortened.

[0128] In the case of the microphone (100) according to the present application, the sound pickup cavity (33) may be defined as the front cavity of the microphone (100), and the distance between the membrane (31) and the substrate (10) is defined as the height of the front cavity. The space of the inner cavity (23), excluding the space of the sound pickup cavity (33), is defined as the rear cavity of the microphone (100). The height of the membrane (31) relative to the inner surface of the protective plate (21) is defined as the height of the rear cavity. In one embodiment, the distance H between the reflection unit (312) and the transmitter (61) is limited to satisfy the condition: 20 µm ≤ H ≤ 100 µm. Due to this limitation, the distance between the transmitter (61) and the membrane (31) is controlled. Additionally, because the distance between the transmitter (61) and the membrane (31) is limited, the flight distance of the laser light in the sound pickup cavity (33) is controlled, and the signal-to-noise ratio (SNR) of the laser signal acquired by the receiver (62) is reduced.

[0129] Since the transmitter (61) is fixed to the substrate (10), the distance between the transmitter (61) and the reflector unit (312) is controlled, and the distance between the substrate (10) and the membrane (31) is also controlled. That is, the height of the front cavity of the microphone (100) is controlled through the aforementioned limitation. Under the premise that the height and space of the internal cavity (23) are fixed, controlling the height of the front cavity of the microphone (100) means increasing the height of the rear cavity of the microphone (100). The higher the height of the rear cavity, the more it helps to increase the signal-to-noise ratio of the diaphragm device (30). In addition, in the aforementioned embodiments of the membrane (31), the main body (311) is only a 1-layer or 2-layer structure, but the microphone (100) can reach a relatively good operating state. Compared to multilayer membranes in conventional technologies, the membrane (31) in the present application is thinner, and the space of the acquired rear cavity is correspondingly larger. This helps to improve the signal-to-noise ratio of the diaphragm device (30).

[0130] Accordingly, the microphone (100) according to the present application can additionally capture external sound vibrations using a laser magnetic mixing device (60) in addition to capturing external sound vibrations using a diaphragm device (30). To ensure that the microphone (100) can achieve a better sound capturing effect, the two sound vibration capturing methods can complement each other, or a method such as a fusion algorithm can be used. Additionally, because the microphone (100) has a better sound capturing effect, the audio capturing capability of the electronic device (200) using the microphone (100) according to the present application is also improved.

[0131] FIG. 12 illustrates a sound capturing method according to the present application. The method comprises the following steps:

[0132] S100: A first voltage signal (V1) is obtained using a laser magnetic mixing device (60), and a second voltage signal (V2) is obtained simultaneously using a diaphragm device (30).

[0133] S200: If the first voltage signal (V1) is less than or equal to a preset threshold (V0), the first voltage signal (V1) is converted into an audio signal; or, if the first voltage signal (V1) is greater than the preset threshold (V0), the second voltage signal (V2) is converted into an audio signal.

[0134] It may be understood that the sound capturing method according to the present application is based on the aforementioned microphone (100) comprising both a laser magnetic mixing device (60) and a diaphragm device (30). Specifically, during step S100, when an external sound vibration occurs, a sound wave is transmitted to a sound pickup cavity (33) through a sound pickup hole (11), causing the membrane (31) to vibrate. In this case, the diaphragm device (30) detects the vibration of the membrane (31), detects the displacement of the membrane (31) in a piezoelectric or piezoresistive manner, forms a second voltage signal (V2), and transmits the second voltage signal (V2) to a processing unit (40). At the same time, the laser magnetic mixing device (60) monitors the vibration of the membrane (31), forms a first voltage signal (V1), and transmits the first voltage signal (V1) to a processing unit (40). In this case, the two voltage signals obtained by the processing unit (40) are formed based on the same external sound vibration. Specifically, the sound vibration captured by the laser magnetic mixing device (60) and the sound vibration captured by the diaphragm device (30) are sound vibrations in the same environment, and the first voltage signal (V1) and the second voltage signal (V2) are both used to reflect sound vibrations in the same environment.

[0135] After individually acquiring the first voltage signal (V1) and the second voltage signal (V2), the processing unit (40) determines the magnitude of the first voltage signal (V1) based on a preset threshold value (V0). Specifically, the processing unit (40) compares the first voltage signal (V1) with the preset threshold value (V0) and can process the first voltage signal (V1) or the second voltage signal (V2) based on the comparison result. Specifically, when the first voltage signal (V1) is less than or equal to the preset threshold value (V0), the processing unit (40) selects to process the first voltage signal (V1) and converts the first voltage signal (V1) into an audio signal that is output in the reverse direction; or, when the first voltage signal (V1) is greater than the preset threshold value (V0), the processing unit (40) selects to process the second voltage signal (V2) and converts the second voltage signal (V2) into an audio signal that is output in the reverse direction.

[0136] Because the laser magnetic mixing device (60) and the diaphragm device (30) have different sound capturing principles, the two devices also have different advantages in sound capturing. The laser magnetic mixing device (60) can be configured to be more sensitive and to collect sound vibration signals with relatively low sound vibration energy and relatively low sound pressure. However, in scenarios of relatively high sound vibration energy and high sound pressure, the noise of the laser magnetic mixing device (60) increases, the signal-to-noise ratio decreases, and the Acoustic Overload Point (AOP) of the laser magnetic mixing device (60) is relatively low. Consequently, overall sound perception ability is degraded. In contrast, the diaphragm device (30) has better perception ability in scenarios of relatively high sound pressure, can control the signal-to-noise ratio of the signal, and has a higher acoustic overload point.

[0137] The energy of external sound vibrations can be identified based on the magnitude of the sound pressure. In the case of the microphone (100) according to the present application, identification and distinction can be performed based on the magnitude of the collected first voltage signal (V1) or the magnitude of the collected second voltage signal (V2). In the sound capturing method of the present application, a preset threshold V0 can be set to control the microphone (100) to capture sound vibrations in a scenario of relatively low sound pressure using a laser magnetic mixing device (60), thereby improving the sensitivity of the microphone (100) and extending the operating range of the microphone (100). In a scenario of relatively high sound pressure, the microphone (100) according to the present application captures sound vibrations by using a diaphragm device (30), thereby ensuring the signal-to-noise ratio of the signal and improving the acoustic overload point of the microphone (100).

[0138] Additionally, since both the first voltage signal (V1) and the second voltage signal (V2) are used to reflect sound vibrations in the same environment, the first voltage signal (V1) and the second voltage signal (V2) can be considered to be time-synchronized. When the processing unit (40) switches from processing the first voltage signal (V1) to processing the second voltage signal (V2), or from processing the second voltage signal (V2) to processing the first voltage signal (V1), signal out-of-synchronization or frame loss does not occur due to the time-synchronization characteristics of the two signals. This ensures that the microphone (100) can continuously capture external sound vibrations and convert the external sound vibrations to obtain continuous audio signals.

[0139] Additionally, based on different structures of the membrane (31) and back cavity (32) within the diaphragm device (30) and different choices of the transmitter (61) and receiver (62) within the laser magnetic mixing device (60), the preset threshold value (V0) in the sound capturing method of the present application is not specified as a unique value. In some embodiments, the preset threshold value (V0) may be set to 0.1V. Specifically, when the magnitude of the first voltage signal (V1) collected by the laser magnetic mixing device (60) is 0.1V or less, the processing unit (40) processes the first voltage signal (V1) as an audio signal; or, when the magnitude of the first voltage signal (V1) is greater than 0.1V, the processing unit (40) processes the second voltage signal (V2) as an audio signal. However, in some other embodiments, the preset threshold may alternatively be defined as a voltage value formed when the laser magnetic mixing device (60) collects an audio signal corresponding to 94 dB to 100 dB. This can also ensure that the laser magnetic mixing device (60) and the diaphragm device (30) capture sound vibrations in more desirable respective operation (i.e., sound pressure) scenarios.

[0140] In the above-described embodiment, it can be understood that the preset threshold value (V0) may be a specific value or a value range. There is some overlap between the preferred operating scenarios of the diaphragm device (30) and the laser magnetic mixing device (60). In other words, in the case of overlaps (i.e., ranges of sound pressure), both the diaphragm device (30) and the laser magnetic mixing device (60) can achieve a relatively good sound vibration capturing effect.

[0141] In some embodiments, after a preset threshold value (V0) is set to a value range, a specific setting may be further performed for the signal conversion method of the processing unit (40). For example, when the processing unit (40) converts a first voltage signal (V1) into an audio signal, if the first voltage signal (V1) does not exceed the upper limit of the preset threshold value (V0), the processing unit (40) may be controlled to continuously convert the first voltage signal (V1) into an audio signal. This ensures audio signal continuity. Alternatively, when the processing unit (40) converts a second voltage signal (V2) into an audio signal, if the first voltage signal (V1) is not less than the lower limit of the preset threshold value (V0), the processing unit (40) may be controlled to continuously convert the second voltage signal (V2) into an audio signal. This may also ensure audio signal continuity. Additionally, the method of the present embodiment also avoids signal desynchronization or frame loss that may be caused by the processing unit (40) frequently switching the signal processing line of the processing unit (40).

[0142] In one embodiment, "obtaining a first voltage signal (V1) using a laser magnetic mixing device (60)" in step S100 may include the following substeps:

[0143] S110: Control the transmitter (61) to emit laser light toward the membrane (31).

[0144] S120: Using a receiver (62), receive the laser light reflected by the membrane (31) and form a first current signal (A1).

[0145] S130: Modulates the first current signal (A1) into the first voltage signal (V1).

[0146] As mentioned above, after the receiver (62) of the laser magnetic mixing device (60) receives the reflected laser light, the signal generated through detection is a current signal (i.e., a first current signal (A1)). However, the preset threshold value (V0) in the method according to the present application is a voltage signal. Therefore, the first current signal (A1) needs to be first modulated and converted into a first voltage signal (V1), and then the processing unit (40) can compare the first voltage signal (V1) with the preset threshold value (V0) for determination. In some embodiments, the laser signal received by the receiver (62) may be a laser light beam formed through magnetic mixing within the sound pickup cavity (33).

[0147] Additionally, in the embodiment, "modulating the first current signal (A1) into the first voltage signal (V1)" in step S130 further comprises the following substeps:

[0148] S131: A transimpedance amplifier is used to convert the first current signal (A1) into the first modulation voltage signal (VT1).

[0149] S132: Amplify the first modulation voltage signal (VT1) using an operational amplifier.

[0150] S133: Filtering is performed on the amplified first modulated voltage signal (VT1) to form the first voltage signal (V1).

[0151] For details, refer to FIG. 13. FIG. 13 is a circuit diagram of signal processing in a microphone (100) according to the present application. In this embodiment, the laser magnetic mixing device (60) is further provided with a transimpedance amplifier (63), an operational amplifier (64), a low-pass filter (65), and a high-pass filter (66), which are further disposed within the laser magnetic mixing device (60). The transimpedance amplifier (63) is electrically connected to a receiver (62), and the transimpedance amplifier (63) is configured to convert a first current signal (A1) into a first modulation voltage signal (VT1). The operational amplifier (64) is electrically connected to the transimpedance amplifier (63), and the operational amplifier (64) is configured to amplify the first modulation voltage signal (VT1) to increase the strength of the first modulation voltage signal (VT1), so that the amplified first modulation voltage signal (VT1) can satisfy the data processing requirements of the processing unit (40). A low-pass filter (65) and a high-pass filter (66) are connected in succession to an operational amplifier (64) and are configured to perform low-pass filtering and high-pass filtering, respectively, on an amplified first modulated voltage signal (VT1) to form a first voltage signal (V1).

[0152] The range of audio frequencies that can be received by a human ear is limited, and after conversion into an audio signal, some of the vibration information carried in the first modulation voltage signal (VT1) exceeds the range of audio frequencies that can be received by a human ear. Therefore, after filtering is performed on the amplified first modulation voltage signal (VT1), the portion of vibration information that exceeds the range of audio frequencies that can be received by a human ear can be filtered out. The first voltage signal (V1) formed after filtering is performed on the amplified first modulation voltage signal (VT1) contains only vibration information within the range of audio frequencies that can be received by a human ear. This can reduce the workload of the processing unit (40).

[0153] In the case of the diaphragm device (30), in the embodiment, "obtaining a second voltage signal (V2) using the diaphragm device (30)" in step S100 may include the following substeps:

[0154] S140: Using a diaphragm chip, a strain signal formed by the displacement of the membrane (31) is collected.

[0155] S150: Converts the strain signal into a second voltage signal (V2).

[0156] Based on the above descriptions of solutions for the diaphragm device (30), in the process of capturing external sound vibrations, the diaphragm device (30) according to the present application needs to use a diaphragm chip to detect vibrations of the membrane (31), convert the displacement of the membrane (31) into a strain signal, and form a second voltage signal (V2) based on the strain signal. The diaphragm chip may be a piezoresistive diaphragm chip (341) or a piezoelectric diaphragm chip (342). When the diaphragm chip is a piezoelectric diaphragm chip (342), the strain signal of the piezoelectric diaphragm chip (342) is specifically a charge signal, that is, a collected charge generated due to deformation of the body (311) made of a piezoelectric material during vibration. In this case, the charge signal is converted into a second voltage signal (V2).

[0157] It should be noted that the operation process in substeps S110 to S130, in which the laser magnetic mixing device (60) operates to form a first voltage signal (V1), and the operation process in substeps S140 and S150, in which the diaphragm device (30) operates to form a second voltage signal (V2), are operations completed by two different processing circuits that operate individually and are executed synchronously. The order of the aforementioned serial numbers does not indicate a specific order of the operation processes of the microphone (100), and in fact, the two operation processes are in parallel. For details, refer to FIG. 14. FIG. 14 is another schematic flowchart of a sound capturing method according to the present application.

[0158] In one embodiment, based on the examples of FIGS. 13 and 14, in the present application, "converting the first voltage signal (V1) or the second voltage signal (V2) into an audio signal" in step S200 may further include the following substeps:

[0159] S210: Converts the first voltage signal (V1) or the second voltage signal (V2) into a digital signal format.

[0160] S220: An algorithm processing is performed on the first voltage signal (V1) or the second voltage signal (V2) converted into a digital signal format to obtain an audio signal.

[0161] Specifically, in this embodiment, the processing unit (40) includes a conversion module (41) and a processing module (42). A first voltage signal (V1) input from a laser magnetic mixing device (60) is in an analog signal format, and a second voltage signal (V2) input from a diaphragm device (30) is also in an analog signal format. When the processing module (42) processes the first voltage signal (V1) or the second voltage signal (V2), it is necessary to first perform digital conversion on the first voltage signal (V1) and the second voltage signal (V2) using the conversion module (41). After the first voltage signal (V1) and the second voltage signal (V2) are converted from analog signals into digital signals, the conversion module (41) transmits the first voltage signal (V1) and the second voltage signal (V2), which are in a digital signal format, to the processing module (42), and the processing module (42) processes the first voltage signal (V1) and the second voltage signal (V2), which are in a digital signal format, into audio signals.

[0162] Refer to FIG. 15. FIG. 15 is a flowchart of another embodiment of a sound capturing method according to the present application. Also refer to FIG. 16. FIG. 16 is a circuit diagram corresponding to the flowchart. After "acquiring a first voltage signal (V1) using a laser magnetic mixing device (60)" in step S100, the method may further include the following:

[0163] S300: Forms a control signal based on the first voltage signal (V1) and outputs the control signal to the transmitter (61) to adjust the wavelength of the laser light emitted toward the membrane (31).

[0164] Specifically, as external sound vibrations change, the optimal operating point of the laser magnetic mixing device (60) (or described as the optimal operating intensity and optimal operating frequency of the laser light) may change in response to the process in which the laser magnetic mixing device (60) collects the first voltage signal (V1). Based on different magnitudes of the first voltage signal (V1), the processing unit (40) may obtain the current optimal operating point of the laser magnetic mixing device (60) through calculations based on a phase-locked loop algorithm, etc. In this case, the processing unit (40) may synchronously parse the wavelength of the laser light emitted by the laser magnetic mixing device (60) when the laser magnetic mixing device (60) operates at the optimal operating point. The processing unit (40) controls the operating current of the transmitter (61) so that the wavelength of the laser light emitted by the laser magnetic mixing device (60) can be controlled. This ensures that the laser magnetic mixing device (60) always collects the first voltage signal (V1) at the optimal operating point.

[0165] In one embodiment, in step S300, "adjusting the wavelength of laser light emitted toward the membrane (31) by the transmitter (61) based on the first voltage signal (V1) and the phase-locked loop algorithm" may further include the following substeps:

[0166] S310: The optimal operating wavelength of the laser light is obtained through calculations based on the first voltage signal (V1), and a control signal is formed.

[0167] S320: Based on the control signal, the magnitude of the operating current of the transmitter (61) is controlled to control the wavelength of the laser light emitted toward the membrane (31).

[0168] Specifically, step S310 may additionally include the following substeps:

[0169] S311: Converts the first voltage signal (V1) from an analog format to a digital format.

[0170] S312: The optimal operating wavelength of the laser light is obtained through calculations based on the first voltage signal (V1) in digital format, and a control signal is formed.

[0171] Step S320 may include the following substeps:

[0172] S321: Converts control signals from digital format to analog format.

[0173] S322: The magnitude of the operating current of the transmitter (61) is controlled based on the control signal of the analog format, thereby controlling the wavelength of the laser light emitted toward the membrane (31) by the transmitter (61).

[0174] Specifically, as mentioned above, the processing unit (40) includes a processing module (42). The optimal operating point of the laser magnetic mixing device (60) is calculated by the processing module (42) based on a first voltage signal (V1) in a digital signal format. Therefore, before the optimal operating wavelength of the laser light is obtained through calculation, the conversion module (41) needs to perform a digital format conversion on the first voltage signal (V1) in an analog format. After the calculation is completed, the processing module (42) needs to return the calculation result to the conversion module (41), and the calculation result is converted by the conversion module (41) from a digital format to an analog control signal in an analog signal format. Next, the transmitter (61) receives the analog control signal and controls the magnitude of the operating current to control the wavelength of the laser light emitted by the transmitter (61).

[0175] In FIG. 15, "converting the first voltage signal (V1) from an analog format to a digital format" in step S310 can be implemented through "converting the first voltage signal (V1) or the second voltage signal (V2) to a digital signal format" in step S210.

[0176] In one embodiment, the method according to the present application is:

[0177] The step of setting the feedback intensity C of the laser magnetic mixing device (60) to less than 1 may be additionally included.

[0178] Specifically, in this embodiment, the feedback strength of the laser magnetic mixing device (60) can be understood as a change in the intensity and frequency of the laser light obtained by the laser light transmitted by the transmitter (61) being magnetically mixed in the sound pickup cavity with respect to the intensity and frequency of the originally emitted laser light, combining the gain of the propagation medium and the optical loss, and experiencing phase superposition. The feedback strength 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 light, the height of the resonant cavity of the laser magnetic mixing device (60), etc. When the feedback strength C > 1, the optical signal received by the receiver (62) may experience a phase change and may be accompanied by high phase noise. When the feedback strength C = 1, the phase jump and phase noise of the strain signal are reduced accordingly. When the feedback strength C < 1, no phase jump occurs in the optical signal received by the receiver (62), and the phase noise is relatively low. Accordingly, in this embodiment, the feedback strength of the laser magnetic mixing device (60) is controlled so that the quality of the laser signal received by the receiver (62) can be guaranteed.

[0179] The foregoing descriptions are merely specific embodiments of the present application and are not intended to limit the scope of protection of the present application. Any modification or substitution readily understood by a person skilled in the art within the technical scope disclosed in the present application, such as removing or adding structural members and changing the shape of structural members, should be within the scope of protection of the present application. The embodiments of the present application and the features in the embodiments may be combined with one another unless there is a conflict. Accordingly, the scope of protection of the present application should be subject to the scope of protection of the claims.

Claims

Claim 1 A sound capturing method applied to a microphone, wherein the microphone comprises a laser self-mixing apparatus and a diaphragm apparatus, wherein the diaphragm apparatus comprises a membrane, wherein the membrane is configured to respond to sound vibrations, and wherein the laser self-mixing apparatus and the diaphragm apparatus are separately configured to detect vibrations of the membrane, and the method comprises: a step of acquiring a first voltage signal using the laser self-mixing apparatus and simultaneously acquiring a second voltage signal using the diaphragm apparatus; and a step of converting the first voltage signal into an audio signal if the first voltage signal is below a lower limit of a preset threshold value. A sound capturing method comprising the step of converting the second voltage signal into an audio signal when the first voltage signal is greater than the upper limit of the preset threshold, and when converting the first voltage signal into the audio signal, continuously converting the first voltage signal into the audio signal when the first voltage signal does not exceed the upper limit of the preset threshold, or when converting the second voltage signal into the audio signal when the first voltage signal is greater than or equal to the lower limit of the preset threshold, continuously converting the second voltage signal into the audio signal. Claim 2 A sound capturing method according to claim 1, wherein the laser magnetic mixing device comprises a transmitter and a receiver, and obtaining a first voltage signal using the laser magnetic mixing device comprises: controlling the transmitter to emit laser light toward the membrane; using the receiver to receive the laser light reflected by the membrane and forming a first current signal; and modulating the first current signal into the first voltage signal. Claim 3 In paragraph 2, the laser magnetic mixing device further comprises a transimpedance amplifier and an operational amplifier, and modulating the first current signal into the first voltage signal comprises: converting the first current signal into a first modulated voltage signal using the transimpedance amplifier; amplifying the first modulated voltage signal using the operational amplifier; and performing filtering on the amplified first modulated voltage signal to form the first voltage signal, a sound capturing method. Claim 4 A sound capturing method according to claim 1, wherein the diaphragm device comprises a diaphragm chip, and acquiring a second voltage signal using the diaphragm device comprises: collecting a strain signal formed by the displacement of the membrane using the diaphragm chip; and converting the strain signal into the second voltage signal. Claim 5 A sound capturing method according to claim 2, further comprising the step of forming a control signal based on the first voltage signal and outputting the control signal to the transmitter to adjust the wavelength of the laser light emitted toward the membrane. Claim 6 A sound capturing method according to claim 5, wherein forming a control signal based on the first voltage signal and outputting the control signal to the transmitter to adjust the wavelength of the laser light emitted toward the membrane comprises: obtaining an optimal operating wavelength of the laser light through a calculation based on the first voltage signal and forming the control signal; and controlling the magnitude of the operating current of the transmitter based on the control signal to control the wavelength of the laser light emitted toward the membrane. Claim 7 A sound capturing method according to claim 1, wherein the feedback coefficient C of the laser magnetic mixing device is less than 1. Claim 8 An electronic device, wherein the electronic device comprises a microphone, and the microphone performs sound pickup using a sound capturing method according to any one of claims 1 to 7. Claim 9 A microphone configured to perform sound pickup using a sound capturing method according to claim 1, comprising a substrate, a protective cover, a laser magnetic mixing device, a diaphragm device, and a processing unit, wherein both the protective cover and the processing unit are fixed to the substrate, and the protective cover and the substrate form an internal cavity through an enclosure, and the laser magnetic mixing device and the diaphragm device are fixed to the internal cavity and each is communicably connected to the processing unit; the diaphragm device comprises a membrane and a back cavity, wherein the back cavity is fixed to the substrate, and the membrane is located on the side of the back cavity away from the substrate, and the membrane and the back cavity form a sound pickup cavity through an enclosure on the substrate; the laser magnetic mixing device comprises a transmitter and a receiver, wherein both the transmitter and the receiver are received in the sound pickup cavity and fixed to the substrate, and the transmitter directs a laser toward the membrane A microphone configured to emit light, wherein the receiver is configured to receive laser light reflected by the membrane; wherein the substrate is additionally provided with a plurality of sound pickup holes, and the sound pickup cavity communicates with the outside through the plurality of sound pickup holes. Claim 10 In claim 9, the membrane comprises a reflective unit, the reflective unit is located on the surface of the membrane facing the substrate, and the laser light emitted by the transmitter is received by the receiver after being reflected by the reflective unit, a microphone. Claim 11 In claim 10, the microphone, wherein the reflection unit is located at the geometric center of the membrane, and the transmitter and the receiver on the substrate are located within the projection area of ​​the reflection unit on the substrate. Claim 12 In claim 9, the diaphragm device comprises a diaphragm chip, and the diaphragm chip is configured to detect vibration of the membrane, form a second voltage signal, and transmit the second voltage signal to the processing unit, a microphone. Claim 13 A microphone according to claim 12, wherein the membrane is a piezoelectric membrane or a piezoresistive membrane, and the diaphragm chip is a piezoelectric diaphragm chip or a piezoresistive diaphragm chip correspondingly. Claim 14 In claim 9, the thickness D of the membrane satisfies the condition: 0.1㎛ ≤ D ≤ 1㎛, a microphone. Claim 15 In claim 10, a microphone in which the distance H between the reflector unit and the transmitter satisfies the condition: 20㎛ ≤ H ≤ 100㎛. Claim 16 An electronic device comprising a microphone according to any one of claims 9 to 15, wherein the microphone is configured to collect an audio signal.

Images