WO2021036416A1 - 麦克风芯片、麦克风及终端设备 - Google Patents

麦克风芯片、麦克风及终端设备 Download PDF

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Publication number
WO2021036416A1
WO2021036416A1 PCT/CN2020/095940 CN2020095940W WO2021036416A1 WO 2021036416 A1 WO2021036416 A1 WO 2021036416A1 CN 2020095940 W CN2020095940 W CN 2020095940W WO 2021036416 A1 WO2021036416 A1 WO 2021036416A1
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Prior art keywords
grating
microphone chip
diaphragm
substrate
light
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PCT/CN2020/095940
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English (en)
French (fr)
Inventor
方东明
李明
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to JP2022512819A priority Critical patent/JP2022546379A/ja
Priority to EP20858536.4A priority patent/EP4021015B1/en
Publication of WO2021036416A1 publication Critical patent/WO2021036416A1/zh
Priority to US17/681,285 priority patent/US11902742B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
    • H04R23/008—Transducers other than those covered by groups H04R9/00 - H04R21/00 using optical signals for detecting or generating sound
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
    • G02F1/125—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves in an optical waveguide structure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/14—Measuring arrangements characterised by the use of optical techniques for measuring distance or clearance between spaced objects or spaced apertures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2290/00—Aspects of interferometers not specifically covered by any group under G01B9/02
    • G01B2290/30—Grating as beam-splitter
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2290/00—Aspects of interferometers not specifically covered by any group under G01B9/02
    • G01B2290/45—Multiple detectors for detecting interferometer signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02015—Interferometers characterised by the beam path configuration
    • G01B9/02027—Two or more interferometric channels or interferometers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02055—Reduction or prevention of errors; Testing; Calibration
    • G01B9/02056—Passive reduction of errors
    • G01B9/02057—Passive reduction of errors by using common path configuration, i.e. reference and object path almost entirely overlapping
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
    • H04R1/04—Structural association of microphone with electric circuitry therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/003—Mems transducers or their use
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2410/00—Microphones
    • H04R2410/03—Reduction of intrinsic noise in microphones

Definitions

  • This application relates to the field of optical chips, in particular to a microphone chip, a microphone and a terminal device.
  • An optical microphone is a microphone that accepts external sound signals through optical fiber or optical structure sensing with light waves as a carrier.
  • the microphone chip in the current optical microphone may include a substrate and a vibrating membrane with a mirror arranged oppositely; a grating substrate with a grating, a light emitter, and a photodetector located between the substrate and the vibrating membrane; and a driving structure and corresponding Drive control circuit.
  • a driving structure and corresponding Drive control circuit When sound pressure acts on the diaphragm, the diaphragm is deformed, which drives the mirror below the diaphragm to move downward. Part of the light emitted by the light emitter is reflected on the lower surface of the grating, and part of the light is transmitted to the mirror through the grating slits.
  • the driving structure is connected with the vibrating membrane, and under the control of the driving control circuit, the driving structure can drive the vibrating membrane to move closer to or away from the grating, so as to adjust the distance between the mirror and the grating to realize the modulation of incident light.
  • the microphone chip is provided with a drive structure and a drive control circuit, this increases the difficulty and complexity of the manufacturing process on the one hand, and on the other hand increases mechanical noise and circuit noise, which affects the pickup performance of the microphone chip.
  • the embodiments of the present application provide a microphone chip, a microphone, and a terminal device.
  • the technical solution is as follows:
  • a microphone chip in a first aspect, includes:
  • a grating group located between the substrate and the diaphragm
  • a light emitter and a light detector located between the substrate and the grating group
  • the grating group includes a plurality of gratings, and at least two gratings of the plurality of gratings have different distances from the reflecting mirror.
  • the microphone chip provided by the embodiment of the present application, at least two of the multiple gratings have different distances from the reflector. Therefore, the distance between the reflector and the grating can be changed without the need for a drive structure and a drive control circuit. It is simple, and because the setting of the driving structure and the driving control circuit is reduced, the difficulty and complexity of the manufacturing process are reduced, and the mechanical noise and circuit noise are reduced. Thus, the sound pickup performance of the microphone chip is effectively improved.
  • any two adjacent gratings to the reflecting mirror are different.
  • the difference g between the distances between at least two gratings of the plurality of gratings and the reflecting mirror satisfies: (2n-1) ⁇ /8- ⁇ /16 ⁇ g ⁇ (2n-1) ⁇ /8+ ⁇ /16, the ⁇ is the wavelength of the light emitted by the light emitter, and n is an integer greater than 0.
  • the difference g between the distances between at least two gratings of the plurality of gratings and the reflecting mirror is an odd multiple of ⁇ /8, where ⁇ is the wavelength of the light emitted by the light emitter.
  • the embodiment of the application reduces the difficulty of the manufacturing process on the basis of simplifying the structure, and ensures that the microphone chip is stably in the linear working area, thereby improving the microphone detection sensitivity and signal-to-noise ratio.
  • the difference between the distances between any two adjacent gratings and the reflecting mirror is an odd multiple of ⁇ /8.
  • the grating group can be fixed between the substrate and the diaphragm in a variety of ways.
  • the following two implementation methods are used as examples for description:
  • the grating group is fixed between the substrate and the diaphragm through the grating base.
  • the microphone chip also includes:
  • a supporting structure the supporting structure is fixed between the substrate and the diaphragm, and the grating base is fixedly connected to the supporting structure.
  • a plurality of gratings of the grating group are arranged on a side of the grating substrate close to the diaphragm and/or a side away from the diaphragm;
  • the light emitter and the light detector are located on the substrate.
  • a plurality of gratings of the grating group are located on a side of the grating substrate close to the diaphragm;
  • the light emitter and the light detector are located on the side of the grating substrate away from the diaphragm.
  • the grating substrate has a first opening.
  • the grating group is fixed between the substrate 11 and the diaphragm 12 through a supporting structure, and the microphone chip further includes:
  • a support structure the support structure is fixed between the substrate and the diaphragm;
  • Each of the gratings is fixed on the supporting structure.
  • the grating substrate can avoid the interaction between the grating substrate and the air, thereby reducing the noise caused by the air damping phenomenon.
  • the diaphragm has a second opening
  • the grating includes a plurality of slits and a peripheral area surrounding the plurality of slits, and the peripheral area has a third opening.
  • the aforementioned first opening, second opening and third opening all have the effect of reducing the air damping phenomenon.
  • a plurality of the second openings are provided on the diaphragm, and at least two of the second openings have different sizes;
  • At least two of the second openings have different shapes.
  • the size range of the second opening is 1-200um; and/or, the total area of the second opening on the diaphragm accounts for 1% to 5% of the total area of the diaphragm.
  • the second openings formed are equivalent to the aforementioned micro-holes, which have a sound absorption effect on high-frequency sound. .
  • the diaphragm is a circular diaphragm.
  • the shape of the diaphragm is circular, such a diaphragm occupies a smaller space area compared to diaphragms with other shapes, which can ensure the miniaturization of the microphone chip.
  • the stress around it is uniform, is not prone to breakage, has a long service life, and can ensure the stability of the performance of the microphone chip.
  • the boundary shape of the grating group is a circle or an arc.
  • the volume of the microphone chip can be effectively reduced; in another In an alternative example, when the microphone chip does not include the grating substrate, when the boundary shape of the grating group and the shape of the diaphragm are both circular, the volume of the microphone chip can be effectively reduced.
  • the microphone chip includes two optical transmitters, wherein the wavelengths of the light emitted by the two optical transmitters are ⁇ 1 and ⁇ 2 respectively ; and the ⁇ satisfies:
  • ⁇ 1 and ⁇ 2 are close, for example , the difference between ⁇ 1 and ⁇ 2 is less than 1, then a larger combined wavelength ⁇ is obtained through the above wavelength formula.
  • the larger the wavelength of the light emitted by an optical transmitter the higher the manufacturing cost.
  • Two optical transmitters with a smaller wavelength are used to achieve a larger combined wavelength ⁇ , and there is no need to directly set the optical transmitter with a larger wavelength. Reduce the manufacturing cost of the microphone chip.
  • the microphone chip includes one optical transmitter and three optical detectors; wherein, the three optical detectors are respectively used to receive the -1 order and three optical detectors diffracted by the grating group. 0-order and +1-order diffracted light.
  • the microphone chip further includes:
  • the control circuit is used to control the light emitter to emit light.
  • a microphone including: the microphone chip of any one of the first aspects, and a packaging structure of the microphone chip.
  • the microphone provided in the embodiments of the present application can be used as a standalone microphone, and can also be applied to scenes that require long-distance high-fidelity pickup of human voices in fields such as intelligent audio, autonomous driving, human-computer interaction, Internet of Things, Internet of Vehicles, and robots.
  • Using the microphone provided by the embodiment of the present application can effectively improve the detection sensitivity of the optical microphone, thereby improving the signal-to-noise ratio and dynamic range of the optical microphone.
  • a terminal device including a processor, a memory, and the microphone chip of any one of the first aspects.
  • the terminal device may be the Internet of Things such as smart speakers, autonomous driving, human-computer interaction, Internet of Vehicles, or robots.
  • the microphone chip is used to collect sound waves, convert the sound waves into electrical signals and input them to the processor;
  • the processor is used to process the electrical signal converted into sound waves
  • the memory is used to store data obtained by the processor processing the electrical signal.
  • the microphone chip provided by the embodiment of the present application, at least two of the multiple gratings have different distances from the reflector. Therefore, the distance between the reflector and the grating can be changed without the need for a drive structure and a drive control circuit. It is simple, and because the setting of the driving structure and the driving control circuit is reduced, the difficulty and complexity of the manufacturing process are reduced, and the mechanical noise and circuit noise are reduced. Thus, the sound pickup performance of the microphone chip is effectively improved.
  • FIG. 1 is a schematic structural diagram of a microphone chip provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of the relationship between the output light intensity and the cavity length L of the F-P cavity provided by an embodiment of the present application;
  • 3 and 4 are schematic top views of two types of grating groups provided by an embodiment of the application.
  • 5 to 15 are schematic cross-sectional views of several grating groups provided by embodiments of the application.
  • 16 to 22 are schematic structural diagrams of several microphone chips provided by embodiments of the application.
  • FIG. 23 and FIG. 24 are schematic top views of another two kinds of grating groups provided by an embodiment of the application.
  • FIG. 25 is a schematic diagram of a top view structure of a grating substrate provided by an embodiment of the present application.
  • FIG. 26 is a schematic diagram of a top view structure of a diaphragm provided by an embodiment of the present application.
  • FIG. 27 is a schematic diagram of the relationship between the diffracted light intensity and the diffraction order provided by an embodiment of the present application.
  • FIG. 28 is a schematic structural diagram of another microphone chip provided by an embodiment of the application.
  • FIG. 29 is a schematic structural diagram of a microphone provided by an embodiment of this application.
  • FIG. 30 is a schematic structural diagram of a terminal device provided by an embodiment of this application.
  • the signal-to-noise ratio (SIGNAL-NOISE RATIO, SNR) is an important indicator of microphone performance.
  • the signal-to-noise ratio of the microphone is equal to the ratio of the signal received by the microphone to the inherent noise of the microphone.
  • the microphone sensitivity represents the acoustic-electric conversion efficiency of the microphone.
  • the inherent noise of the microphone includes mechanical noise and circuit noise (such as thermal noise, shot noise, or dark current noise, etc.).
  • An optical microphone is a microphone that accepts external sound signals through optical fiber or optical structure sensing with light waves as a carrier. It converts sound signals into light signals. Optical microphones can not only "pick” signals, but also “select” signals, thereby suppressing various noise signals in the environment, which is more reliable than electrical microphones.
  • the optical microphone uses photoacoustic sensing technology and photoelectric signal demodulation technology to sense sound signals and vibrations. It has excellent performance that traditional microphones do not have, such as high sensitivity, strong anti-electromagnetic interference, wide detection spectrum range or remote monitoring Calls, etc., suitable for use in complex electromagnetic environments and harsh environmental conditions.
  • optical microphones can be divided into three types: intensity modulation type, phase modulation interference type and polarization state modulation type.
  • the phase modulation interference type optical microphone adopts the diffraction grating method for signal demodulation.
  • a diffraction grating is an optical element that makes the amplitude or phase (or both) of incident light undergo periodic spatial modulation through a regular structure.
  • the specific principle of the diffraction grating method is to use sound pressure to change the optical path of light, change the interference fringes of the grating, change the electrical signal detected by the photodetector, and restore the sound signal through phase demodulation technology.
  • the embodiment of the present application provides a microphone chip 1, and the microphone chip 1 may also be referred to as a sound sensor or a microphone sensor. As shown in Figure 1, the microphone chip 1 includes:
  • the substrate 11 and the diaphragm 12 are usually arranged in parallel; a mirror 121 located on the side of the diaphragm 12 close to the substrate 11; a grating group located between the substrate 11 and the diaphragm 12; The light emitter 14 and the light detector 15 between the substrate 11 and the grating group.
  • the substrate 11 may be a silicon-based or a printed circuit board (Printed Circuit Board, PCB).
  • the light emitter 14 is used to emit laser light
  • the light detector 15 is used to detect the light diffracted by the grating group.
  • the light emitter 14 may be a vertical cavity surface emitting laser (VCSEL) or other types of lasers
  • the light detector is a photodetector (PD, Photodetector) or a diode light detector.
  • the diaphragm 12 is a sensitive structure for sensing sound pressure. Under the action of external sound pressure, a certain small deformation will occur. The small deformation can be estimated by the light detector 15 through the intensity change of the detected light signal To calculate the sound pressure.
  • the material of the diaphragm can be semiconductor materials (such as single crystal silicon), metals, metal alloys, or high molecular polymers.
  • the reflector 121 can be attached to the diaphragm 12 by pasting or coating, and is used to reflect the light emitted by the light emitter 14.
  • the reflector 121 is a metal film.
  • the reflectivity of the reflector 121 is usually above 90%.
  • the grating group includes a plurality of gratings 13, and at least two gratings 13 of the plurality of gratings have different distances from the mirror 121.
  • the distance between the grating and the mirror refers to the vertical distance between the two. In one case, the distance is the distance between the upper surface of the grating and the upper surface of the mirror (that is, the gap between the two). Vertical distance; in another case, the distance is the vertical distance between the lower surface of the mirror and the upper surface of the grating. The embodiments of this application do not limit this.
  • the thickness of the grating 13 should not be too thick to prevent the laser light emitted by the light emitter 14 from passing through the grating 13 to the reflector 121; in general, the thickness of the grating 13 can be in the range of 10nm-100um, which is not specifically limited in this application .
  • the grating group includes two gratings 13, and assuming that the distance from the mirror to the grating is the vertical distance between the lower surface of the mirror and the upper surface of the grating, the distance between the two gratings 13 and the mirror 121 They are d1 and d2, which are different.
  • the microphone chip provided by the embodiment of the present application, at least two of the multiple gratings have different distances from the reflector. Therefore, there is no need to provide a drive structure and a drive control circuit, so that the distance between at least one grating and the reflector meets the requirements. Thereby ensuring the sensitivity of the microphone chip, not only the structure is simple, but also due to the reduction of the drive structure and the setting of the drive control circuit, the difficulty and complexity of the manufacturing process are reduced, the mechanical noise and the circuit noise are reduced, and the signal noise of the microphone chip is improved. ratio. Thus, the sound pickup performance of the microphone chip is effectively improved.
  • the cavity formed by the mirror 121 and the grating 13 is equivalent to a Fabry-Perot (Fabry-Perot, FP) cavity, and the distance between the mirror 121 and the grating 13 is equivalent to The cavity length L of the FP cavity.
  • FIG. 2 is a schematic diagram of the relationship between the output light intensity and the cavity length L of the FP cavity provided by an embodiment of the present application.
  • the horizontal axis is the cavity length L
  • the unit is 10 -6 m (meters)
  • the vertical axis is the normalized (also called normalization) output light intensity, the unit is 1.
  • the cavity length change ⁇ L satisfies the relationship: - ⁇ /16 ⁇ L ⁇ /16, there is a certain linear relationship between the output light intensity and the cavity length L, that is, The cavity length L is in the linear region in FIG. 2.
  • the linear relationship between the output light intensity of the microphone chip and the cavity length L is referred to as the microphone chip being in a linear working area.
  • the distance between at least two gratings in the plurality of gratings and the reflector (that is, the vertical difference or height difference between the two gratings) g is ⁇ Odd multiple of /8, the ⁇ is the wavelength of the light emitted by the light emitter. That is, the distance between the mirror and the grating group is not limited, and it is only necessary to ensure that the drop g of at least two gratings is an odd multiple of ⁇ /8. It should be understood that the difference between the distance between at least two of the gratings and the mirror, g, which is an odd multiple of ⁇ /8, is also within the protection scope of the present application.
  • g is different from an odd multiple of ⁇ /8.
  • the value is less than or equal to ⁇ /16; the grating can be realized by micro-nano machining, and the manufacturing precision of the distance difference between the two gratings can be accurate to the nm level.
  • the distance between any two adjacent gratings to the mirror is different; further, the distance between any two adjacent gratings to the mirror (that is, the vertical difference or height difference between the two) g is ⁇ / Odd multiples of 8.
  • any grating in the grating group is the reference grating A
  • the distance L1 between the reference grating A and the mirror is in the linear region
  • the grating B adjacent to the reference grating A and the mirror The distance L2 is usually in the nonlinear region. That is, L1 and L2 satisfy:
  • both m and n are non-negative integers, namely 0, 1, 2....
  • L2 is in a non-linear region (that is, not a linear region) except for the endpoints.
  • the values of P4 and P3 on the vertical axis are the same. Obviously, only the end point P3 of this distance L2 is in the linear region, or basically not Belongs to the linear region.
  • L1 and L2 satisfy:
  • m is a non-negative integer, namely 0, 1, 2....
  • L2 is the distance corresponding to points P5 to P6 in Figure 2. Since the slopes of the corresponding points of the area between P5 and P6 and the area between P2 and P3 are the same, therefore, the grating B The distance L2 from the mirror is in the linear region. Among them, the position-corresponding point means that the values of the two points on the vertical axis are equal.
  • L1 and L2 satisfy:
  • p is a positive integer, namely 1, 2...
  • m is a non-negative integer, namely 0, 1, 2....
  • the range of L2 is transformed into: It can be seen with reference to Fig. 2 that the distance L2 is in the linear region.
  • the distance between the reference grating A and the mirror is the distance corresponding to the points P3 to P4 in Figure 2 above
  • the distance L2 from the grating B to the mirror is the distance corresponding to the points P7 to P8 in Figure 2 above. Since the area between the points P7 and P8 and the area between the points P1 and P3 have the same slopes of the corresponding points, the grating
  • the distance L2 between B and the mirror is in the linear region. Among them, the position-corresponding point means that the values of the two points on the vertical axis are equal.
  • the minimum difference g between the distances between at least two of the gratings and the mirror can be ⁇ /8 ⁇ 106.3nm, the g value can also be 318.8nm (3 ⁇ /8) or 531.3nm (5 ⁇ /8).
  • the microphone chip can be simply debugged, such as the distance between the grating group and the reflector, and then the microphone chip can be simply tested to achieve the microphone chip in the linear working area.
  • the assembly, debugging and testing process Both are relatively simple.
  • Increasing the detection sensitivity of the microphone chip can effectively improve the signal-to-noise ratio of the microphone chip, and one of the main measures to improve the detection sensitivity of the microphone chip is to make the microphone chip in a linear working area.
  • the traditional microphone chip controls the diaphragm through the drive structure and the corresponding drive control circuit, so that the distance between the mirror and the grating is located in the linear region.
  • Such adjustment complexity is relatively high.
  • the embodiment of the application replaces the grating with a grating group.
  • the difficulty of the manufacturing process is reduced, and the microphone chip is ensured to be in the linear working area stably. Thereby improving the detection sensitivity of the microphone, as well as the signal-to-noise ratio.
  • the grating is an optical element composed of a large number of parallel slits 131.
  • the slits 131 are formed by a plurality of grid bars 132 arranged in parallel, wherein every two adjacent grid bars form a slit 131.
  • the slits 131 of the grating can be of equal width and equal spacing (the spacing is the width of the grid), or unequal width and/or unequal spacing.
  • the boundary shape of the grating group can also have many kinds, as long as the normal diffraction and phase interference functions of the grating group are ensured.
  • the boundary shape of the grating group refers to the shape enclosed by the edge of the orthographic projection of the grating group on the substrate, that is, the boundary shape of the grating group when viewed from above.
  • the boundary shape of the grating group shown in FIG. 3 is a rectangle
  • the boundary shape of the grating group shown in FIG. 4 is a circle.
  • the boundary shape of the grating group may also be an ellipse, a trapezoid, a triangle, or other irregular shapes.
  • the light spot projected by the light emitter is usually circular.
  • the boundary area of the grating group is slightly greater than or equal to the projected spot area
  • the boundary shape of the grating group is a circle or an arc shape
  • such a grating group will diffract light compared to a grating group whose boundary shape is other shapes
  • the effect is not much different, but the overall area of the grating group is reduced, and the occupied space area is small, which can ensure the miniaturization of the microphone chip.
  • the length of the grating bars in the grating may be equal or unequal. Taking the aforementioned FIGS. 3 and 4 as an example, the lengths of the grating bars in the grating in FIG. 3 are equal, and the lengths of the grating bars in the grating in FIG. 4 are not equal.
  • the cross-section of each grid bar can be rectangular, triangular, zigzag, or irregular shape, etc.
  • FIG. 5 is a schematic diagram of the AA cross-sectional view of the grating group shown in FIG. 3 or FIG. 4. In FIG.
  • each grating bar 132 is rectangular as an example for description. It is worth noting that, in Fig. 5, the double-grating grating group adopts the "left high and right low” implementation mode. In fact, the "left low and right high” implementation mode can also be adopted.
  • the shapes and/or sizes of different gratings in the grating group may be the same or different.
  • the embodiments of this application do not limit this. Wherein, when the shapes and/or sizes of the gratings in the grating group are the same, the difficulty and complexity of the manufacturing process can be reduced.
  • the grating group in the embodiment of the present application can be obtained by combining multiple gratings in various forms, as long as it is ensured that the distance difference between at least two gratings in the multiple gratings to the reflector satisfies the aforementioned difference formula.
  • FIGS. 5 to 15 are the structures of several exemplary grating groups provided by the embodiments of the application. Among them, FIG. 5 shows that the grating group includes two gratings (that is, the grating group is a double grating structure).
  • Fig. 6 to Fig. 9 are schematic diagrams of the structure when the grating group includes 3 gratings (that is, the grating group is a three-grating structure); Figs.
  • the grating group 10 to 12 are the grating group including 4 gratings (that is, the grating group is four gratings).
  • 13-15 are schematic diagrams of the structure when the grating group includes five gratings (that is, the grating group has a five-grating structure). Any one of the structural schematic diagrams in FIGS. 5 to 15 may be an A-A cross-sectional view of the grating group shown in FIG. 3 or FIG. 4. It is worth noting that the grating group in the embodiment of the present application may be based on a dual grating structure with a distance difference after performing one or more operations such as axisymmetric, center symmetry, angle rotation, etc. on the grating section (that is, the aforementioned AA section). structure.
  • the grating group may also include 6 gratings or 7 gratings, etc., and its cross-sectional shape may also be other shapes. This is not repeated in the embodiment of the application.
  • the grating group can be fixed between the substrate and the diaphragm in a variety of ways.
  • the following two implementation methods are used as examples for description:
  • the grating group is fixed between the substrate and the diaphragm through the grating base.
  • the microphone chip 1 further includes:
  • the grating base 16 can be arranged parallel to the substrate; the support structure 17, the The supporting structure 17 is fixed between the substrate 11 and the diaphragm 12, and the grating base 16 and the supporting structure 17 are fixedly connected.
  • the grating substrate 16 can have a variety of shapes, such as the step shape shown in FIGS. 1, 17 to 21 or the plate shape shown in FIG. 16, as long as the grating group is effectively fixed and the grating in the fixed grating group It suffices that the aforementioned distance difference exists between them.
  • the use of a plate-shaped grating substrate to fix the grating group can simplify the manufacturing difficulty of the grating substrate and reduce the manufacturing cost.
  • the material of the grating substrate needs to be matched with the light emitted by the emitter to ensure that the light emitted by the light emitter 14 passes through.
  • the grating substrate 16 may be made of a transparent material, such as transparent plastic, glass, or quartz. If the light emitted by the emitter 34 is infrared light, the grating substrate 16 can be made of a filter capable of transmitting infrared light (that is, the filter is used to filter other light except infrared light).
  • the grating group can be fixed on the grating substrate by directly making, pasting or transferring on the grating substrate.
  • the gratings in the grating group can be fixed on at least one side of the grating substrate 16 according to the situation, and the positions of the light emitter 14 and the light detector 15 can also be adjusted accordingly.
  • the embodiment of the present application uses the following optional methods as examples to illustrate the arrangement of the gratings in the grating group:
  • the multiple gratings 13 of the grating group are arranged on the side of the grating substrate 16 close to the diaphragm 12.
  • the multiple gratings 13 of the grating group are arranged on the side of the grating substrate 16 away from the diaphragm 12.
  • the multiple gratings 13 of the grating group are arranged on the side of the grating substrate 16 close to the diaphragm 12 and the side away from the diaphragm 12. That is, a part of the grating 13 in the grating group is arranged on the side of the grating substrate 16 close to the diaphragm 12, and the other part of the grating 13 is arranged on the side of the grating substrate 16 close to the diaphragm 12.
  • the light emitter 14 and the light detector 15 are located on the substrate 11.
  • FIGS. 17 to 19 the working principle of the microphone chip provided by the embodiment of the present application is described: when sound pressure acts on the diaphragm, the diaphragm 12 is deformed, driving the mirror 121 below the diaphragm 12 upward or downward
  • part of the light emitted by the light emitter 14 is reflected on the lower surface of the grating 13, and a part of it is transmitted to the mirror 121 through the grating slit, and then reflected by the mirror 121 to the upper surface of the grating 13, so that the light with optical path difference Diffraction and phase interference occur through the grating 13, and after receiving the diffracted light from the grating through the photodetector 15, the optical signal is converted into an electrical signal, and the electrical signal is transmitted to a subsequent processing chip, and the processing chip performs signal demodulation.
  • the multiple gratings 13 of the grating group are located on the side of the grating substrate 16 close to the diaphragm 12; the light emitter 14 and the light detector 15 are located on the side of the grating substrate 16 away from the vibration film.
  • the arrangement of the device is more compact, and the distance from the substrate 11 to the light emitter 14 and the light detector 15 can be reduced, so as to reduce the overall thickness of the microphone chip and realize the miniaturization of the microphone chip.
  • the supporting structure 17 can be implemented in multiple ways, as long as it is ensured that the grating base 16 is effectively fixed between the substrate 11 and the diaphragm 12.
  • the supporting structure 17 may include a plurality of columnar structures, such as a spacer (Photo Spacer, PS), and the two ends of each columnar structure (that is, the end where the two parallel surfaces are located) are connected to each other, respectively.
  • the substrate 11 and the diaphragm 12 are fixedly connected.
  • the multiple columnar structures can be evenly distributed around the edges of the substrate 11 and the diaphragm 12 to achieve effective support for the substrate 11 and the diaphragm 12.
  • the support structure 17 is a ring structure, that is, its top view shape is a ring, and the two ends of the support structure 17 are respectively fixedly connected to the substrate 11 and the diaphragm 12.
  • the supporting structure 17 can be distributed around the edges of the substrate 11 and the diaphragm 12, and the substrate 11 and the diaphragm 12 are enclosed to form a cavity for placing the grating group, the light emitter and the photodetector, so as to achieve the effect of the substrate 11 and the diaphragm 12. support.
  • the cavity is a closed cavity, which can block external dust and improve the service life of the microphone chip.
  • the supporting structure can be made of frame sealing glue.
  • the supporting structure can also be other supporting structures, such as a hollow support frame (which can achieve good heat dissipation of the microphone chip), etc., which is not limited in this application.
  • the grating substrate 16 can be fixed on the supporting structure 17 in multiple ways.
  • the side surface of the support structure 17 has a card interface, and the edge of the grating substrate 16 can be inserted into the card interface to be fixedly connected to the support structure 17.
  • the support structure 17 may have a plurality of card interfaces corresponding to at least two sides of the support structure 17 (for example, at least two sides of the front, rear, left, and right sides of the support structure 17 when the support structure 17 is placed horizontally), so that The grating substrate 16 is more firmly clamped on the supporting structure 17.
  • the supporting structure 17 is the supporting structure in the aforementioned first alternative implementation, one or more of the plurality of columnar structures is provided with the card interface on the side facing the grating substrate; if the supporting structure 17 is the aforementioned In the support structure in the second optional implementation manner, one or more inner surfaces of the support structure 17 are provided with the card interface.
  • the support structure 17 is composed of an upper support 171 and a lower support 172, and the edge of the grating substrate 16 can be clamped to the upper support 171 and the lower support 172. 172 are fixedly connected to the supporting structure 17.
  • the support structure 17 is the support structure in the aforementioned first alternative implementation, each of the plurality of column structures is divided into two upper and lower parts, and the aforementioned upper support 171 is composed of the upper part of the plurality of column structures.
  • the aforementioned lower support 172 is composed of lower parts of multiple columnar structures; if the support structure 17 is the support structure in the aforementioned second alternative implementation, the support structure 17 is divided into upper and lower parts, and the upper support 171 is It is the upper part of the support structure 17, and the lower support 172 is the lower part of the support structure 17.
  • the edge of the grating substrate 16 may be fixedly connected to the supporting structure 17 by means of adhesive bonding (ie, glue or adhesive connection).
  • the grating group is fixed between the substrate and the diaphragm through a supporting structure.
  • the microphone chip 1 further includes:
  • the supporting structure 17 is fixed between the substrate 11 and the diaphragm 12; each grating 13 is fixed on the supporting structure 17.
  • the structure and material of the support structure 17 can refer to the structure and material of the support structure 17 in the foregoing embodiment, and the fixing method of the grating 13 on the support structure 17 can also refer to the structure and material of the grating substrate 16 on the support structure 17 in the foregoing embodiment.
  • the fixing method will not be repeated in the embodiment of this application.
  • the fixed connection between the grating group and the supporting structure can be realized by micro-machining and micro-assembly technology.
  • the structure of the grating group may be as shown in FIG. 3 and FIG. 4, and the respective grating bars of each grating may be arranged at intervals and not connected to each other.
  • the structure of each grating in the grating group can be as shown in FIG. 23 and FIG. 24.
  • the grating also includes a connection to each grating 132.
  • the connection bar 133 can be a linear connection bar or a non-linear connection bar, such as a curved connection bar.
  • connection bar 133 can ensure the connection of the various grid bars in the grating and play a role of fixing the grid bars.
  • Fig. 23 and Fig. 24 both take the grating group including two gratings as an example for description, but the number of gratings in the grating group is not limited.
  • the A-A cross-sectional schematic diagrams of the grating groups shown in FIGS. 23 and 24 and similar grating groups can still be referred to the foregoing FIGS. 5 to 15, and details are not repeated in the embodiment of the present application.
  • each grating can be made by etching (for example, laser etching) a plurality of parallel notches on a transparent sheet-like structure such as a glass sheet, and the notches are the aforementioned slits. Between every two notches is the aforementioned grating, so that each grating is actually a sheet-like structure with a notch, and the aforementioned grating substrate 16 can be fixed on the support structure 17 by using the fixing method of the aforementioned grating substrate 16 on the support structure 17 .
  • the grating substrate will introduce mechanical noise due to the phenomenon of air damping.
  • the air damping phenomenon refers to a physical phenomenon in which the amplitude of the mechanical resonance motion of the device gradually decreases due to the existence of air resistance.
  • the grating is directly fixed to the supporting structure without setting the grating substrate.
  • the grating is similar to floating between the diaphragm and the substrate, thereby reducing the thickness of the microphone chip and realizing the miniaturization of the chip.
  • the grating substrate is provided, so the interaction between the grating substrate and the air can be avoided, thereby reducing the noise caused by the air damping phenomenon.
  • the grating substrate 16 has a first opening 161.
  • FIG. 25 is a schematic top view of a grating substrate 16.
  • the grating substrate 16 has one or more of the first openings 161.
  • the shape and/or size (or area) of the plurality of first openings 161 may be the same or different.
  • the shape of the plurality of first openings 161 may include one or more of a circle, a rectangle, a honeycomb shape (ie, a regular hexagon), a triangle, an ellipse, or other irregular shapes.
  • the first opening 161 includes two types of openings, which are circular and irregular, as examples, but the embodiment of the present application does not limit the shape of the first opening.
  • the grating substrate 16 Since the larger the number of the first openings, the larger the size, the smaller the interaction between the grating substrate 16 and the air, and the air damping phenomenon is correspondingly weakened. Therefore, under the premise of ensuring that the grating substrate 16 can effectively carry the grating group, it is possible to provide as many first openings as possible and larger in size. Further, the plurality of first openings 161 may be uniformly distributed on the grating substrate, for example, distributed in a center-symmetrical or axisymmetrical manner, which can ensure that the grating substrate is uniformly stressed and increase the life of the grating substrate.
  • the shape and/or size of the boundary of the grating base (that is, the boundary of the orthographic projection of the grating base on the substrate) needs to be matched with the grating group in order to effectively carry the grating group.
  • the shape of the grating substrate may be the same as the boundary shape of the grating group.
  • the boundary shape of the grating substrate is as shown in FIG. 25, and both shapes are circular.
  • the boundary size of the grating base can be greater than or equal to the boundary size of the grating group to ensure that the area where the grating group is projected on the substrate is located in the area where the grating base is projected on the substrate.
  • the diameter of the circle corresponding to the grating substrate is larger than the diameter of the circle corresponding to the grating group.
  • FIG. 26 is a schematic diagram of a top view of the diaphragm 12.
  • the diaphragm 12 has one or more second openings 122.
  • the shape and/or size (or area) of the plurality of second openings 122 may be the same or different.
  • the shape of the plurality of second openings 122 may include one or more of a circle, a rectangle, a triangle, an ellipse, or other irregular shapes.
  • the second opening 122 includes a circular shape. The opening is described as an example, but the embodiment of the present application does not limit the shape of the second opening.
  • the plurality of second openings 122 may be uniformly distributed on the diaphragm 12, for example, distributed in a center-symmetrical or axisymmetrical manner, which can ensure that the diaphragm 12 is uniformly stressed and increase the life of the diaphragm 12. Since the reflector is usually located in the middle of the diaphragm 12, the second openings 122 are usually distributed on the edge of the diaphragm 12.
  • the sizes of at least two second openings 122 are different; and/or, the shapes of at least two second openings 122 are different.
  • the size and shape of the plurality of second openings 122 can be obtained through simulation through simulation software, can also be set according to the experience of experts, and can also be obtained according to actual needs or theoretical calculations.
  • the diaphragm of the traditional microphone chip is not open. If the diaphragm is not open, the sensitivity of the microphone chip will become worse with the increase of atmospheric pressure, and it is easy to cause the microphone when the pressure difference between the inside and outside the cavity is too large. The chip is damaged.
  • the embodiment of the present application opens holes on the diaphragm, which reduces air damping, reduces mechanical noise, and improves the signal-to-noise ratio of the microphone. On the other hand, it allows the pressure inside and outside the cavity to communicate, which can also release the stress of the diaphragm to a certain extent.
  • a second opening 122 may be provided on the diaphragm 12 based on the micro-perforation sound absorption theory to achieve the sound absorption effect of the diaphragm.
  • the micro-perforation sound absorption theory refers to the provision of micro-holes (also called micro-perforations) with a diameter of less than 1.0 mm on a film (or plate structure) with a thickness of less than 1.0 mm (millimeters), and the opening rate (that is, the opening area)
  • the sum of the ratio of the total area of the diaphragm) is usually 1% to 5%, that is, the total area of the second opening on the diaphragm accounts for 1% to 5% of the total area of the diaphragm, and a certain thickness is reserved on one side of the diaphragm.
  • 5-20 cm (centimeters) of air layer to form a micro-perforated sound-absorbing structure, which is a resonant high-acoustic resistance structure with sound-absorbing characteristics.
  • the second openings formed are equivalent to the aforementioned micro-holes, which have a sound absorption effect on high-frequency sound. .
  • the size range of the second opening on the diaphragm may be 1-200um (micrometers).
  • the combination of second openings of different sizes can increase the width of the absorbed frequency (also called the sound absorption bandwidth), and realize the filtering of high-frequency noise of multiple frequencies, thereby expanding Filter out the range of noise.
  • the sound absorption effect is formed by arranging the second opening on the diaphragm, which is an effective noise reduction method and can improve the sensitivity, signal-to-noise ratio and dynamic range of the microphone chip.
  • the microphone sensor is used to pick up human voices, and the human voice frequency range is 20 Hz (hertz) to 20 kHz (kilohertz), so it is necessary to filter out noise higher than 20 kHz.
  • multiple second openings with a fixed diameter of 10 um or 20 um can be provided to filter out noise higher than 20 kHz.
  • multiple second openings with multiple diameter combinations ranging from 10um to 20um to filter out noise higher than 20kHz such as the combination of second openings with diameters of 10um and 20um, so that the diaphragm
  • the sound absorption bandwidth is greatly increased, and the high-frequency sound absorption effect will be better.
  • the shape of the diaphragm 12 can be a circle, a rectangle, a triangle, or other irregular shapes, as long as it can produce a small deformation to achieve the sound pickup performance of the microphone chip.
  • the diaphragm 12 is a circular diaphragm.
  • the shape of the diaphragm is circular, such a diaphragm occupies a smaller space area compared to diaphragms with other shapes, which can ensure the miniaturization of the microphone chip.
  • the stress around it is uniform, is not prone to breakage, has a long service life, and can ensure the stability of the performance of the microphone chip.
  • the peripheral area may have a third opening to reduce the air damping phenomenon.
  • Noise is an area located at the edge of the grating that does not affect the diffraction and phase interference functions of the grating. For example, in some scenes, if the grating is a grating in the grating group shown in Fig. 23 or Fig.
  • the grating includes a connecting bar
  • the peripheral area is the area where the connecting bar 133 is located, a third Aperture, or the grating is obtained by engraving etching marks on a transparent sheet-like structure such as a glass sheet
  • the peripheral area is the peripheral area surrounding the plurality of marks on the transparent sheet-like structure, and a third opening can be provided on the periphery. hole.
  • the microphone chip is provided with a grating substrate with first openings, part or all of the third openings can be connected to the first openings to reduce the barrier of the grating to the first openings.
  • the size of the grating itself is relatively small, that is, the grating has no or almost no peripheral area.
  • the grating in the grating group as shown in Figure 3 and Figure 4 there is no need to set the grating opening. hole.
  • the shape and/or size (or area) of the plurality of third openings may be the same or different.
  • the shape of the plurality of third openings may include one or more of a circle, a rectangle, a triangle, an ellipse or other irregular shapes, and the shape of the third opening may refer to the aforementioned first opening and the first opening.
  • the shape of three openings may refer to the top structure diagram of the grating 13 in FIG. 25.
  • the relationship between the diffracted light intensity of a grating and the diffraction order is shown in FIG. 27, the horizontal axis represents the order of diffracted energy, and the vertical axis represents the normalized diffracted light intensity.
  • the diffracted light passing through the mirror and the upper reflecting surface of the grating will produce a phase difference of ⁇ /2.
  • the diffraction energy of the diffraction pattern is mainly concentrated in the ⁇ 1 order; when the distance between the mirror and a grating is an even multiple of ⁇ /4, the difference between the mirror and the upper reflective surface of the grating The diffracted light will produce a phase difference of 0.
  • the diffraction energy of the diffraction pattern is mainly concentrated on the 0th order, and the light intensity at the ⁇ 1st order is 0.
  • the aforementioned grating group is equivalent to a special grating, and the relationship curve between the diffracted light intensity and the diffraction order can also refer to FIG. 27.
  • the diffracted light intensity is concentrated at the 0th order (that is, the maximum light intensity appears at the 0th order) or is concentrated at At ⁇ 1 level (that is, the maximum light intensity appears at ⁇ 1 level), the diffracted light intensity of the grating group is concentrated at the 0 level and/or ⁇ 1 level.
  • the diffraction When the distance between the reflecting mirror and a certain grating is not an integer multiple of ⁇ /4, for example, when the distance between at least two gratings in the plurality of gratings and the reflecting mirror is an odd multiple of ⁇ /8, the diffraction
  • the relationship curve between light intensity and diffraction order is equivalent to the curve formed by the weighted superposition of the solid curve and the dashed curve in Figure 27.
  • the diffraction energy is mainly concentrated in the 0th and ⁇ 1st orders. In some cases, the diffraction energy will also be partially Distributed at ⁇ 3 levels.
  • the number and location of the light emitters and light detectors need to be determined based on the relationship between the aforementioned diffracted light intensity and the number of diffraction orders.
  • the grating equation can be used to calculate the light receiver’s Target position; in another alternative, it can be obtained by using simulation software based on one or more of the parameters of the position of the light emitter, the light-emitting angle of the light emitter, the position of the reflector, and the position of the grating group. The target position of the optical receiver.
  • the light detector When there is at least one target position, the light detector is set at one or more target positions.
  • the light at the target position is stronger than the designated light intensity threshold, for example, the designated light intensity threshold is 0.
  • the target position is the aforementioned -3, -1, 0, +1, and +3 corresponding positions.
  • Fig. 1 Fig. 16, Fig. 18, and Fig. 20 to Fig. 22, there can be one light emitter; and as shown in Fig. 17 and Fig. 19, there can also be two or more light emitters.
  • the wavelength of the light emitters can be the same or different.
  • the number of optical receivers can be one, two, three (as shown in Figure 1, Figure 16, Figure 18 to Figure 22), four, five, or six ( Figure 17).
  • the microphone chip includes 1 light emitter 14 and 3 light detectors 15; among them, the 3 light detectors 15 are respectively used to receive -1 diffracted by the grating group. Order, 0 order and +1 order diffracted light. In this way, the light intensity detection sensitivity can be higher when the light intensity detection is performed at the 0th order and ⁇ 1 order where the diffraction energy is concentrated. Using the combination of the light emitter and the light detector shown in FIG. 18 or FIG. 22 can effectively adapt to this application scenario.
  • the microphone chip includes 2 light emitters 14 and 6 light detectors 15; the 6 light detectors 15 are respectively used to receive the -3 and -1 orders diffracted by the grating group. Order, 0 order, 0 order, +1 order and +3 order diffracted light.
  • the microphone chip includes 2 light emitters 14 and 5 light detectors 15; the 5 light detectors 15 are respectively used to receive the -3, -1, 0, and + which are diffracted by the grating group. 1st order and +3 order diffracted light.
  • the receiving effect of the diffracted light intensity can be improved, and the detection sensitivity can be improved.
  • the diffracted light intensity of ⁇ 5th order and later is very weak.
  • a photodetector is generally used to receive the diffracted light intensity of 0th, ⁇ 1, and ⁇ 3 orders at most. In order to save the manufacturing cost of the microphone chip.
  • the wavelength ⁇ of the light emitted by the aforementioned optical transmitter may have different definitions in different application scenarios.
  • the wavelength ⁇ of the light emitted by the light transmitter is equal to the wavelength of the light emitted by the one light transmitter; in another case, when the microphone chip includes multiple Optical transmitter, the wavelengths of the light emitted by the plurality of optical transmitters are equal, then the wavelength ⁇ of the light emitted by the optical transmitter is equal to the wavelength of the light emitted by any one of the plurality of optical transmitters; in another case
  • the wavelength ⁇ of the light emitted by the light emitter is equal to the combined wavelength of the multiple wavelengths.
  • the light emitted by the emitter has k wavelengths, which are ⁇ 1 to ⁇ k , and k is an integer greater than 1.
  • the wavelength ⁇ of the light emitted by the optical transmitter satisfies the combined wavelength formula:
  • max means seeking the maximum value, i ⁇ j, i ⁇ [1,k], j ⁇ [1,k].
  • the combined wavelength ⁇ is the maximum value of the combined wavelengths of every two wavelengths among the k kinds of wavelengths.
  • the microphone chip includes two optical transmitters 14, the wavelengths of the light emitted by the two optical transmitters 14 are ⁇ 1 and ⁇ 2 respectively , and the two wavelengths are different; then ⁇ satisfies the wavelength formula:
  • ⁇ 1 and ⁇ 2 are close, for example , the difference between ⁇ 1 and ⁇ 2 is less than 1, then a larger combined wavelength ⁇ is obtained through the above wavelength formula.
  • the larger the wavelength of the light emitted by an optical transmitter the higher the manufacturing cost.
  • two optical transmitters with a smaller wavelength are used to achieve a larger combined wavelength ⁇ , and there is no need to directly set the optical transmitter with a larger wavelength. The manufacturing cost of the microphone chip can be reduced.
  • FIGS. 16 to 22 in the embodiments of the present application are cross-sectional views of the microphone chip.
  • the light emitter and the light detector are deployed in the same horizontal direction, but in fact the light emitter and the light
  • the positions of the detectors are slightly staggered, they do not overlap each other, and they do not block each other.
  • the top-view shape of the light emitter is a round shape (ie ring shape), which is arranged around the light detector, or the light emitter and the light detector are arranged next to each other.
  • the figure is only schematically drawn, which is not limited in the embodiment of the present application.
  • the microphone chip 1 further includes:
  • the control circuit 18 can be electrically connected to the light emitter 14 for controlling the light emitter 14 to emit light.
  • the control circuit 18 may be located on the substrate 11.
  • the microphone chip 1 may also include a driving circuit, which may be electrically connected to the light emitter 14 for driving the light emitter 14 to emit light.
  • the driving circuit may be located on the substrate 11.
  • the microphone chip 1 may also include a receiving circuit, which may be electrically connected to the photodetector 15 for receiving the signal output by the photodetector 15.
  • the receiving circuit may be located on the substrate 11.
  • the microphone chip can also be equipped with other optical elements for adjusting the optical path, such as a mirror or a prism.
  • the microphone chip provided by the embodiment of the present application, at least two of the multiple gratings have different distances from the reflector. Therefore, the distance between the reflector and the grating can be realized without the need for a drive structure and a drive control circuit.
  • the change not only has a simple structure, but also reduces the difficulty and complexity of the manufacturing process and reduces the mechanical noise and circuit noise due to the reduction of the drive structure and the setting of the drive control circuit. Thus, the sound pickup performance of the microphone chip is effectively improved.
  • the difference g between the distances between at least two of the gratings and the mirror is an odd multiple of ⁇ /8, on the basis of simplifying the structure, the difficulty of the manufacturing process is reduced, and the microphone chip is stable in linearity. Work area. Thereby improving the microphone detection sensitivity and signal-to-noise ratio.
  • An embodiment of the present application provides a microphone, as shown in FIG. 29, including: the microphone chip 1 provided in any of the foregoing embodiments of the present application, and the packaging structure 2 of the microphone chip 1.
  • the microphone may further include a main board 3, and both the microphone chip 1 and the packaging structure 2 are arranged on the main board.
  • the packaging structure 2 may be a casing, and the packaging structure 2 has a sound inlet 21 so that sound signals pass through the sound inlet 21 and pass into the microphone chip 1 through the inside of the casing.
  • the microphone may also include a processing chip 4 and a package 5 of the processing chip, a signal import connection point (pad) 61 for importing signals to the processing chip 4 and a signal export connection point 62 for exporting signals from the processing chip 4.
  • the package body 5 can be insulating glue.
  • the microphone chip 1 and the processing chip 4 are electrically connected through a signal line 71, and the processing chip 4 and the signal introduction connection point 61 are electrically connected through a signal line 72.
  • the processing chip 4 may be an application specific integrated circuit (ASIC) chip.
  • ASIC application specific integrated circuit
  • the main board may be a PCB.
  • the substrate of the microphone chip 1 can be an integral structure with the motherboard, that is, the substrate is the motherboard.
  • the sound inlet 21 is staggered from the microphone chip 1, that is, the orthographic projection of the sound inlet 21 on the motherboard and the orthographic projection of the microphone chip 1 on the motherboard do not overlap, which can prevent pollutants from the external environment from entering the microphone chip. Improve the service life of the microphone chip.
  • the microphone may also be equipped with other optical elements outside the microphone chip for adjusting the optical path, such as a mirror or a prism.
  • the microphone provided in the embodiments of the present application can be used as a standalone microphone, and can also be applied to scenes that require long-distance high-fidelity pickup of human voices in fields such as intelligent audio, autonomous driving, human-computer interaction, Internet of Things, Internet of Vehicles, and robots.
  • Using the microphone provided by the embodiment of the present application can effectively improve the detection sensitivity of the optical microphone, thereby improving the signal-to-noise ratio and dynamic range of the optical microphone.
  • An embodiment of the present application provides a terminal device, including the microphone provided in the foregoing embodiment of the present application.
  • the terminal device may be the Internet of Things such as smart speakers, autonomous driving, human-computer interaction, Internet of Vehicles, or robots.
  • FIG. 30 shows a structural block diagram of a terminal device 3000 provided by an exemplary embodiment of the present application.
  • the terminal device 3000 can be: smart phones, tablet computers, MP3 players (Moving Picture Experts Group Audio Layer III, dynamic image expert compression standard audio layer 3), MP4 (Moving Picture Experts Group Audio Layer IV, dynamic image expert compression standard Audio level 4) Player, laptop or desktop computer.
  • the terminal device 3000 may also be called user equipment, portable terminal device, laptop terminal device, desktop terminal, and other names.
  • the terminal device 3000 includes a processor 3001 and a memory 3002.
  • the processor 3001 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and so on.
  • the processor 3001 can adopt at least one hardware form among DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array, Programmable Logic Array). achieve.
  • the processor 3001 may also include a main processor and a coprocessor.
  • the main processor is a processor used to process data in the awake state, also called a CPU (Central Processing Unit, central processing unit); the coprocessor is A low-power processor used to process data in the standby state.
  • the processor 3001 may be integrated with a GPU (Graphics Processing Unit, image processor), and the GPU is used for rendering and drawing content that needs to be displayed on the display screen.
  • the processor 3001 may further include an AI (Artificial Intelligence) processor, and the AI processor is used to process computing operations related to machine learning.
  • AI Artificial Intelligence
  • the memory 3002 may include one or more computer-readable storage media, which may be non-transitory.
  • the memory 3002 may also include high-speed random access memory and non-volatile memory, such as one or more magnetic disk storage devices and flash memory storage devices.
  • the non-transitory computer-readable storage medium in the memory 3002 is used to store at least one instruction.
  • the terminal device 3000 may optionally further include: a peripheral device interface 3003 and at least one peripheral device.
  • the processor 3001, the memory 3002, and the peripheral device interface 3003 may be connected by a bus or a signal line.
  • Each peripheral device can be connected to the peripheral device interface 3003 through a bus, a signal line, or a circuit board.
  • the peripheral device includes: at least one of a radio frequency circuit 3004, a touch display screen 3005, a camera 3006, an audio circuit 3007, a positioning component 3008, and a power supply 3009.
  • the peripheral device interface 3003 can be used to connect at least one peripheral device related to I/O (Input/Output) to the processor 3001 and the memory 3002.
  • the processor 3001, the memory 3002, and the peripheral device interface 3003 are integrated on the same chip or circuit board; in some other embodiments, any one of the processor 3001, the memory 3002, and the peripheral device interface 3003 or The two can be implemented on a separate chip or circuit board, which is not limited in this embodiment.
  • the radio frequency circuit 3004 is used for receiving and transmitting RF (Radio Frequency, radio frequency) signals, also called electromagnetic signals.
  • the radio frequency circuit 3004 communicates with a communication network and other communication devices through electromagnetic signals.
  • the radio frequency circuit 3004 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals.
  • the radio frequency circuit 3004 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, and so on.
  • the radio frequency circuit 3004 can communicate with other terminal devices through at least one wireless communication protocol.
  • the wireless communication protocol includes, but is not limited to: metropolitan area networks, various generations of mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and/or WiFi (Wireless Fidelity, wireless fidelity) networks.
  • the radio frequency circuit 3004 may also include a circuit related to NFC (Near Field Communication), which is not limited in this application.
  • the display screen 3005 is used to display UI (User Interface).
  • the UI can include graphics, text, icons, videos, and any combination thereof.
  • the display screen 3005 also has the ability to collect touch signals on or above the surface of the display screen 3005.
  • the touch signal may be input to the processor 3001 as a control signal for processing.
  • the display screen 3005 may also be used to provide virtual buttons and/or virtual keyboards, also called soft buttons and/or soft keyboards.
  • the display screen 3005 may be a flexible display screen, which is arranged on the curved surface or the folding surface of the terminal device 3000. Furthermore, the display screen 3005 can also be set as a non-rectangular irregular pattern, that is, a special-shaped screen.
  • the display screen 3005 may be made of materials such as LCD (Liquid Crystal Display) and OLED (Organic Light-Emitting Diode).
  • the camera assembly 3006 is used to capture images or videos.
  • the camera assembly 3006 includes a front camera and a rear camera.
  • the front camera is set on the front panel of the terminal device, and the rear camera is set on the back of the terminal device.
  • the camera assembly 3006 may also include a flash.
  • the flash can be a single-color flash or a dual-color flash. Dual color temperature flash refers to a combination of warm light flash and cold light flash, which can be used for light compensation under different color temperatures.
  • the audio circuit 3007 may include the aforementioned microphone 1 and a speaker.
  • the microphone 1 is used to collect the sound waves of the user and the environment, and convert the sound waves into electrical signals and input them to the processor 3001.
  • the processor 3001 is used to process the received electrical signals.
  • the memory 3002 can store the processed data to To realize the recording or storage of data corresponding to the sound waves; or the electric signal processed by the microphone 1 can also be input to the radio frequency circuit 3004 to realize voice communication.
  • the microphone can also be an array microphone or an omnidirectional collection microphone.
  • the speaker is used to convert the electrical signal from the processor 3001 or the radio frequency circuit 3004 into sound waves.
  • the speaker can be a traditional thin-film speaker or a piezoelectric ceramic speaker.
  • the speaker can not only convert the electrical signal into human audible sound waves, but also convert the electrical signal into human inaudible sound waves for distance measurement and other purposes.
  • the audio circuit 3007 may also include a headphone jack.
  • the positioning component 3008 is used to locate the current geographic location of the terminal device 3000 to implement navigation or LBS (Location Based Service, location-based service).
  • the positioning component 3008 may be a positioning component based on the GPS (Global Positioning System, Global Positioning System) of the United States, the Beidou system of China, the Granus system of Russia, or the Galileo system of the European Union.
  • the power supply 3009 is used to supply power to various components in the terminal device 3000.
  • the power source 3009 may be alternating current, direct current, disposable batteries, or rechargeable batteries.
  • the rechargeable battery may support wired charging or wireless charging.
  • the rechargeable battery can also be used to support fast charging technology.
  • the terminal device 3000 further includes one or more sensors 3010.
  • the one or more sensors 3010 include, but are not limited to: an acceleration sensor 3011, a gyroscope sensor 3012, a pressure sensor 3013, a fingerprint sensor 3014, an optical sensor 3015, and a proximity sensor 3016.
  • the acceleration sensor 3011 can detect the magnitude of acceleration on the three coordinate axes of the coordinate system established by the terminal 3000.
  • the acceleration sensor 3011 can be used to detect the components of gravitational acceleration on three coordinate axes.
  • the processor 3001 may control the touch display screen 3005 to display the user interface in a horizontal view or a vertical view according to the gravity acceleration signal collected by the acceleration sensor 3011.
  • the acceleration sensor 3011 may also be used for the collection of game or user motion data.
  • the gyroscope sensor 3012 can detect the body direction and rotation angle of the terminal device 3000, and the gyroscope sensor 3012 can cooperate with the acceleration sensor 3011 to collect the user's 3D actions on the terminal device 3000. Based on the data collected by the gyroscope sensor 3012, the processor 3001 can implement the following functions: motion sensing (such as changing the UI according to the user's tilt operation), image stabilization during shooting, game control, and inertial navigation.
  • the pressure sensor 3013 may be arranged on the side frame of the terminal device 3000 and/or the lower layer of the touch display screen 3005.
  • the processor 3001 performs left and right hand recognition or quick operation according to the holding signal collected by the pressure sensor 3013.
  • the processor 3001 controls the operability controls on the UI interface according to the user's pressure operation on the touch display screen 3005.
  • the operability control includes at least one of a button control, a scroll bar control, an icon control, and a menu control.
  • the fingerprint sensor 3014 is used to collect the user's fingerprint.
  • the processor 3001 identifies the user's identity according to the fingerprint collected by the fingerprint sensor 3014, or the fingerprint sensor 3014 identifies the user's identity according to the collected fingerprint.
  • the processor 3001 authorizes the user to perform related sensitive operations, including unlocking the screen, viewing encrypted information, downloading software, paying, and changing settings.
  • the fingerprint sensor 3014 may be provided on the front, back or side of the terminal device 3000. When a physical button or a manufacturer logo is provided on the terminal device 3000, the fingerprint sensor 3014 can be integrated with the physical button or the manufacturer logo.
  • the optical sensor 3015 is used to collect the ambient light intensity.
  • the processor 3001 may control the display brightness of the touch screen 3005 according to the intensity of the ambient light collected by the optical sensor 3015. Specifically, when the ambient light intensity is high, the display brightness of the touch display screen 3005 is increased; when the ambient light intensity is low, the display brightness of the touch display screen 3005 is decreased.
  • the processor 3001 may also dynamically adjust the shooting parameters of the camera assembly 3006 according to the ambient light intensity collected by the optical sensor 3015.
  • the proximity sensor 3016 also called a distance sensor, is usually set on the front panel of the terminal device 3000.
  • the proximity sensor 3016 is used to collect the distance between the user and the front of the terminal device 3000.
  • the processor 3001 controls the touch screen 3005 to switch from the on-screen state to the off-screen state; when the proximity sensor 3016 When it is detected that the distance between the user and the front of the terminal device 3000 is gradually increasing, the processor 3001 controls the touch display screen 3005 to switch from the rest screen state to the bright screen state.
  • FIG. 12 does not constitute a limitation on the terminal device 3000, and may include more or fewer components than shown in the figure, or combine certain components, or adopt different component arrangements.
  • the embodiments of this application can surround the boundary shape of the grating group, the shape of the grating, the material of the grating substrate, the shape of the diaphragm, the material of the diaphragm, the shape of the mirror, the mirror material, and the grating.
  • a certain combination of the distance difference between the optical transmitter and the optical detector can form a variety of implementations of the microphone chip to obtain various embodiments.
  • the grating group is not only limited to double gratings, but can also have a certain three Grating, four-grating or five-grating, etc., as long as the grating group matches the shape of the light spot emitted by the light emitter (for example, the grating group can cover the light spot of the light emitter in the arrangement direction of the photodetector); the diaphragm can have Holes, non-holes, and holes with different diameters; the cross-sectional shape of the grating bars can be rectangular, triangular, zigzag, or irregular. It should be noted that in the description of the drawings, the same symbols are used for similar or identical parts. The implementations not shown or described in the drawings are those known to those skilled in the art.
  • the program can be stored in a computer-readable storage medium.
  • the storage medium mentioned can be a read-only memory, a magnetic disk or an optical disk, etc.

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Abstract

本申请公开了一种麦克风芯片、麦克风及终端设备，可用于手机、录音机以及其他需要进行声音收集的设备中。该麦克风芯片，所述麦克风芯片包括：相对的基板和振膜；位于所述振膜上靠近所述基板的一侧的反射镜；位于所述基板和振膜之间的光栅组；位于所述基板与所述光栅组之间的光发射器和光探测器；其中，所述光栅组包括多个光栅，该多个光栅中至少两个光栅到所述反射镜的距离不同。本申请降低了制造工艺的难度和复杂度，减少了机械噪声和电路噪声。

Description

麦克风芯片、麦克风及终端设备
本申请要求于2019年8月30日提交的申请号为201910817689.X、发明名称为“麦克风芯片、麦克风及终端设备”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
本申请涉及光学芯片领域，特别涉及一种麦克风芯片、麦克风及终端设备。
背景技术
光学麦克风是以光波为载体，通过光纤或光学结构传感的方式接受外界的声音信号的麦克风。
目前的光学麦克风中的麦克风芯片可以包括相对设置的基板和具有反射镜的振膜；位于基板和振膜之间的设置有光栅的光栅基底、光发射器和光探测器；以及驱动结构和相应的驱动控制电路。当声压作用在振膜上，振膜发生形变，带动振膜下方的反射镜向下移动，光发射器发出的光，一部分在光栅下表面发生反射，一部分透过光栅狭缝透射到反射镜，被反射镜再次反射到光栅上表面，这样具有光程差的光通过光栅发生衍射以及相位干涉，光探测器接收到光栅的衍射光后，将光信号转化为电信号，并将电信号传输至后续的处理芯片，由该处理芯片进行信号解调。该驱动结构与振膜连接，驱动结构在驱动控制电路的控制下可以带动振膜靠近或远离光栅运动，以调整反射镜与光栅的距离从而实现对入射光的调制。
但是，由于麦克风芯片中设置有驱动结构和驱动控制电路，这样一方面增加制造工艺的难度和复杂度，另一方面会增加机械噪声和电路噪声，影响麦克风芯片的拾音性能。
发明内容
本申请实施例提供了一种麦克风芯片、麦克风及终端设备。所述技术方案如下：
第一方面，提供了一种麦克风芯片，所述麦克风芯片包括：
相对的基板和振膜；
位于所述振膜上靠近所述基板的一侧的反射镜；
位于所述基板和振膜之间的光栅组；
位于所述基板与所述光栅组之间的光发射器和光探测器；
其中，所述光栅组包括多个光栅，所述多个光栅中至少两个光栅到所述反射镜的距离不同。
本申请实施例提供的麦克风芯片，所述多个光栅中至少两个光栅到反射镜的距离不同，因此，无需设置驱动结构以及驱动控制电路，即可实现反射镜与光栅距离的变化，不仅结构简单，还由于减少了驱动结构以及驱动控制电路的设置，而降低了制造工艺的难度和复杂度，减少了机械噪声和电路噪声。从而有效提高了麦克风芯片的拾音性能。
进一步地，任意相邻的两个光栅到所述反射镜的距离不同。
可选地，所述多个光栅中至少两个光栅到所述反射镜的距离之差g满足：(2n-1)λ/8-λ/16≤g≤(2n-1)λ/8+λ/16，所述λ为所述光发射器发射的光的波长，n为大于0的整数。
可选地，所述多个光栅中至少两个光栅到所述反射镜的距离之差g为λ/8的奇数倍，所述λ为所述光发射器发射的光的波长。
本申请实施例通过将光栅替换为光栅组，在简化结构的基础上，降低了制造工艺难度，并保证了麦克风芯片稳定地处于线性工作区，从而提高麦克风探测灵敏度和信噪比。
进一步地，任意相邻的两个光栅到所述反射镜的距离之差为λ/8的奇数倍。
本申请实施例中光栅组可以通过多种方式固定在基板和振膜之间，下面以以下两种实现方式为例进行说明：
在第一种实现方式中，光栅组通过光栅基底固定在基板和振膜之间。所述麦克风芯片还包括：
位于所述基板和振膜之间的光栅基底，所述光栅基底用于布置所述光栅组，并透过所述光发射器发射的光；
支撑结构，所述支撑结构固定于所述基板和振膜之间，所述光栅基底与所述支撑结构固定连接。
可选地，所述光栅组的多个光栅布置在所述光栅基底的靠近所述振膜的一侧和/或远离所述振膜的一侧；
所述光发射器和所述光探测器位于所述基板上。
可选地，所述光栅组的多个光栅位于所述光栅基底的靠近所述振膜的一侧；
所述光发射器和所述光探测器位于所述光栅基底的远离所述振膜的一侧。
可选地，所述光栅基底具有第一开孔。
在第二种实现方式中，光栅组通过支撑结构固定在基板11和振膜12之间，所述麦克风芯片还包括：
支撑结构，所述支撑结构固定于所述基板和振膜之间；
每个所述光栅固定在所述支撑结构上。
在第二种实现方式中，通过将光栅直接与支撑结构固定，无需设置光栅基底，光栅类似于悬浮在振膜和基板之间，从而减少麦克风芯片的厚度，实现芯片小型化，并且由于未设置光栅基底，因此可以避免光栅基底与空气的相互作用，从而减少了空气阻尼现象所带来的噪声。
可选地，所述振膜上具有第二开孔；
和/或，所述光栅包括多个狭缝和环绕所述多个狭缝的周边区域，所述周边区域上具有第三开孔。
前述第一开孔、第二开孔和第三开孔均具有减少空气阻尼现象的作用。
可选地，所述振膜上设置有多个所述第二开孔，至少两个所述第二开孔的尺寸不同；
和/或，至少两个所述第二开孔的形状不同。
例如，述第二开孔的尺寸范围是1-200um；和/或，所述振膜上第二开孔的总面积占所述振膜总面积的1％至5％。
根据微穿孔吸声理论，在振膜上开孔，如果开孔得到的第二开孔的数目和直径适当，形成的第二开孔即相当于前述微孔，对高频声音有吸声效应。第二开孔的尺寸越小，吸收的频率越高。这样可以有效滤除麦克风芯片所处环境中的高频噪声。
可选地，所述振膜为圆形振膜。
当振膜的形状为圆形时，这样的振膜相对于形状为其他形状的振膜，占用空间面积较小，能够保证麦克风芯片的小型化。并且，圆形振膜在受力时，其周围的应力均匀，不容易发生破裂，使用寿命较长，可以保证麦克风芯片性能的稳定性。
可选地，所述光栅组的边界形状为圆形或圆弧形。
在一种可选示例中，当麦克风芯片包括光栅基底时，当光栅组的边界形状、振膜的形状以及光栅基底的形状均为圆形时，可以有效减少麦克风芯片的体积；在另一种可选示例中，当麦克风芯片不包括光栅基底时，当光栅组的边界形状与振膜的形状均为圆形时，可以有效减少麦克风芯片的体积。
可选地，所述麦克风芯片包括2个所述光发射器，其中，所述2个所述光发射器发射的光的波长分别为λ 1和λ 2；所述λ满足：
Figure PCTCN2020095940-appb-000001
双波长的检测范围，从单波长的λ 1/4或λ 2/4提高到λ/4，最大检测灵敏度是在h＝λ/8，h为反射镜到光栅的距离。通过设置两种波长可以避开检测灵敏度低的检测点，扩大麦克风芯片的线性工作区，在一定范围内增大麦克风芯片的测量量程。
并且，当两个发光波长不同的光发射器的波长接近时，例如λ 1和λ 2的差值小于1，则通过上述波长公式，得到了一个更大的合成波长λ。通常一个光发射器发出的光的波长越大，其制造成本较高，则采用波长较小的两个光发射器来实现较大的合成波长λ，无需直接设置波长较大的光发射器，降低麦克风芯片的制造成本。
可选地，所述麦克风芯片包括1个所述光发射器和3个所述光探测器；其中，所述3个所述光探测器分别用于接收所述光栅组衍射的-1级、0级和+1级的衍射光。
可选地，所述麦克风芯片还包括：
控制电路，所述控制电路用于控制所述光发射器发光。
第二方面，提供一种麦克风，包括：第一方面任一所述的麦克风芯片，以及所述麦克风芯片的封装结构。
本申请实施例提供的麦克风可以作为单独的麦克风使用，也可以应用于智能音响、自动驾驶、人机交互等物联网、车联网、机器人等领域需要长距离高保真拾取人声的场景。采用本申请实施例提供的麦克风，可以有效提高光学麦克风的探测灵敏度，以此提高光学麦克风的信噪比和动态范围等性能。
第三方面，提供一种终端设备，包括处理器、存储器以及第一方面任一所述的麦克风芯片。示例的，该终端设备可以为智能音响、自动驾驶、人机交互等物联网、车联网或机器人等。
其中，所述麦克风芯片用于采集声波，将声波转换成电信号输入至所述处理器；
所述处理器，用于对声波转换成的电信号进行处理；
所述存储器，用于存储所述处理器对所述电信号处理得到的数据。
本申请实施例提供的麦克风芯片，所述多个光栅中至少两个光栅到反射镜的距离不同，因此，无需设置驱动结构以及驱动控制电路，即可实现反射镜与光栅距离的变化，不仅结构简单，还由于减少了驱动结构以及驱动控制电路的设置，而降低了制造工艺的难度和复杂度，减少了机械噪声和电路噪声。从而有效提高了麦克风芯片的拾音性能。
附图说明
图1是本申请实施例提供的一种麦克风芯片的结构示意图；
图2是本申请实施例提供的输出光强与F-P腔的腔长L的关系示意图；
图3和图4为本申请实施例提供的两种光栅组的俯视示意图；
图5至图15分别为本申请实施例提供的几种光栅组的截面示意图；
图16至图22分别为本申请实施例提供的几种麦克风芯片的结构示意图；
图23和图24为本申请实施例提供的另外两种光栅组的俯视示意图；
图25是本申请实施例提供的一种光栅基底的俯视结构示意图；
图26是本申请实施例提供的一种振膜的俯视结构示意图；
图27是本申请实施例提供的一种衍射光强与衍射级数的关系示意图；
图28为本申请实施例提供的另一种麦克风芯片的结构示意图；
图29为本申请实施例提供的一种麦克风的结构示意图；
图30为本申请实施例提供的一种终端设备的结构示意图。
具体实施方式
随着物联网技术的发展，各种智能车、智能家居、智慧城市等智能化场景越来越多。在这些智能化场景中，通过麦克风进行声音的拾取，尤其远距离声音的可靠拾取，是一个技术难题。
信噪比(SIGNAL-NOISE RATIO，SNR)是麦克风性能的一个重要指标，麦克风的信噪比等于麦克风接收的信号与麦克风固有噪声之比。麦克风灵敏度表示麦克风的声-电转换效率，麦克风固有噪声包括机械噪声和电路噪声(例如含热噪声、散粒噪声或暗电流噪声等)。
对于常用的电学麦克风(如驻极体麦克风或电容式麦克风等)来说，麦克风录到声音信号的同时，也会录到周围环境的各种噪声信号，如果录音距离较远，将会导致麦克风录音信号的信噪比不足，从而使得麦克风拾取的声音信号模糊不清，可读性差。因此，光学麦克风应运而生。光学麦克风是以光波为载体，通过光纤或光学结构传感的方式接受外界的声音信号的麦克风。其将声音信号转化为光信号。光学麦克风不仅能够“拾取”信号，而且还能够“挑选”信号，从而抑制环境中各种噪声信号，相较于电学麦克风拾音的可靠性要高。光学麦克风采用光声传感技术和光电信号解调技术，对声音信号和振动进行传感，具有传统麦克风不具备的优异性能，比如灵敏度高、抗电磁干扰强、探测频谱范围宽或远距离监控通话等，适合于复杂电磁环境和恶劣环境条件下使用。
为了便于读者理解，下面对光学麦克风的工作原理进行简单介绍。根据工作原理，光学麦克风可分为三种类型：强度调制型、相位调制干涉型和偏振态调制型。其中，相位调制干涉型的光学麦克风，采用衍射光栅法进行信号解调。其中，衍射光栅是通过有规律的结构，使入射光的振幅或相位(或两者同时)受到周期性空间调制的光学元件。衍射光栅法的具体原理为利用声压改变光的光程，使光栅的干涉条纹发生变化，使得光探测器探测到的电信号发生变化，并通过相位解调技术还原声音信号。
本申请实施例提供一种麦克风芯片1，该麦克风芯片1也可以称为声音传感器或者麦克风传感器。如图1所示，麦克风芯片1包括：
相对的基板11和振膜12，该基板11和振膜12通常平行设置；位于振膜12上靠近基板11的一侧的反射镜121；位于基板11和振膜12之间的光栅组；位于基板11与光栅组之间的光发射器14和光探测器15。
其中，基板11可以是硅基或印制电路板(Printed Circuit Board，PCB)。光发射器14用于发射激光，光探测器15用于探测经过光栅组衍射后的光。示例的，光发射器14可以为垂直腔面发射激光器(Vertical Cavity Surface Emitting Laser，VCSEL)或其他类型激光器，光探测器为光电探测器(PD，Photodetector)或二极管光检测器。
该麦克风芯片1中，振膜12是感受声压的敏感结构，在外界声压作用下，会发生一定的微小形变，该微小形变可被光探测器15通过检测到的光信号的强度变化推算出来，从而计算声压。振膜的材料可以为半导体材料(如单晶硅)、金属、金属合金或高分子聚合物等。
反射镜121可以通过粘贴或者镀膜的方式附着于振膜12上，用于反射光发射器14发出的光。示例的，该反射镜121是一层金属薄膜。可选地，该反射镜121的反射率通常在90％以上。
光栅组包括多个光栅13，所述多个光栅中至少两个光栅13到反射镜121的距离不同。本申请实施例中，光栅与反射镜的距离指的是两者的垂直距离，在一种情况下，该距离为光栅的上表面与反射镜的上表面之间(即两者的间隙)的垂直距离；在另一种情况下，该距离为反射镜的下表面与光栅的上表面之间的垂直距离。本申请实施例对此不做限定。光栅13的厚度不能太厚，以防止光发射器14发出的激光无法透过光栅13到达反射镜121；一般情况下，光栅13的厚度可以为10nm-100um的范围内，本申请不做具体限定。
如图1所示，假设光栅组包括2个光栅13，假设反射镜到光栅的距离为反射镜的下表面与光栅的上表面之间的垂直距离，则2个光栅13到反射镜121的距离分别为d1和d2，两者不同。
由于光栅和反射镜的之间的距离需通过装配方式实现，很难制作得非常精确，精度通常是在10um甚至mm级别，无法满足精度要求，所以在传统的麦克风芯片中，会设置有驱动结构和驱动控制电路来调整振膜12位置，从而保证反射镜和光栅之间的距离满足要求，保证麦克风芯片的灵敏度；然而，这样一方面会增加制造工艺的难度和复杂度，另一方面会增加机械噪声和电路噪声，无法保证麦克风芯片的信噪比，影响麦克风芯片的拾音性能。
而本申请实施例提供的麦克风芯片，所述多个光栅中至少两个光栅到反射镜的距离不同，因此，无需设置驱动结构以及驱动控制电路，让至少一个光栅与反射镜的距离满足要求，从而保证麦克风芯片的灵敏度，不仅结构简单，还由于减少了驱动结构以及驱动控制电路的设置，而降低了制造工艺的难度和复杂度，减少了机械噪声和电路噪声，提高了麦克风芯片的信噪比。从而有效提高了麦克风芯片的拾音性能。
具体地，在本申请实施例中，反射镜121与光栅13形成的腔体，相当于法布里-珀罗(Fabry-Perot，F-P)腔，反射镜121与光栅13之间的距离相当于F-P腔的腔长L。如图2所示，图2是本申请实施例提供的输出光强与F-P腔的腔长L的关系示意图。其中横轴为腔长L，单位为10 -6m(米)，纵轴是归一化(也称标准化)后的输出光强，单位为1。由图2可知，当入射光波长λ为一定值时，输出光强与F-P腔的腔长L为一近似余弦函数。当腔长L等于λ/4的偶数倍，即L＝2mλ/4时(m为整数)，麦克风芯片的输出光强取得最大值(即图2中M点)；而当腔长L等于λ/4的奇数倍，即L＝(2m+1)λ/4时(m为整数)，麦克风芯片的输 出光强取得最小值(即图2中N点)，上述两种情况下，余弦函数均为非线性的，麦克风芯片的灵敏度最低。以图2中横轴变化范围为λ/4的一段余弦函数为例，在余弦函数的P2点(在该点余弦函数曲线的斜率取得最大值)，输出光强的线性最好，灵敏度也最高。在P2点，当麦克风芯片受到的外界扰动很小时(腔长变化量ΔL满足关系：-λ/16<ΔL<λ/16，即腔长变化量ΔL在图中P1点到P3点之间的长度为λ/8的范围内)，输出光强与腔长L存在一定线性关系，通过测量输出光强的变化量，就可以较为准确地反推出外部声压变化的大小。
由此可知，对于F-P腔的腔长L，其初始的腔长满足L＝nλ/4+λ/8时输出光强的线性最好，n为整数。在此基础上，腔长变化量ΔL满足关系：-λ/16<ΔL<λ/16，输出光强与腔长L存在一定线性关系，也即是，
Figure PCTCN2020095940-appb-000002
腔长L处于图2中的线性区域。本申请实施例将麦克风芯片输出光强与腔长L存在这种线性关系称为麦克风芯片处于线性工作区。
可选地，在本申请实施例提供的麦克风芯片中，所述多个光栅中至少两个光栅到反射镜的距离之差(即两者在竖直方向上的落差或者高度差)g为λ/8的奇数倍，该λ为光发射器发射的光的波长。也即是，不限定反射镜到光栅组的距离，只需保证至少两个光栅的落差g为λ/8的奇数倍即可。应理解，多个光栅中至少两个光栅到反射镜的距离之差g与λ/8的奇数倍有一定差别也在本申请的保护范围内，例如，g为与λ/8的奇数倍相差小于等于λ/16的值；光栅可以通过微纳机械加工实现，两个光栅之间的距离差的制作精度可以精确到nm级别。
其中，任意相邻两个光栅到反射镜的距离不同；进一步地，任意相邻两个光栅到反射镜的距离之差(即两者在竖直方向上的落差或者高度差)g为λ/8的奇数倍。
参考前述原理以及图2，假设光栅组中的任一个光栅为基准光栅A，若该基准光栅A与反射镜的距离L1处于线性区域内，则与该基准光栅A相邻的光栅B与反射镜的距离L2通常处于非线性区域内。即L1和L2满足：
Figure PCTCN2020095940-appb-000003
Figure PCTCN2020095940-appb-000004
其中，m和n均为非负整数，即0、1、2...。
则L2的范围由公式二变形为：
Figure PCTCN2020095940-appb-000005
参考图2可以看出，L2除端点外均处于非线性区域(即不是线性区域)内。
例如，假设该基准光栅A与反射镜的距离L1为前述图2中P1至P3点对应距离，即
Figure PCTCN2020095940-appb-000006
光栅B与该基准光栅A到反射镜的距离之差g为λ/8，即，n＝3，m＝0，则光栅B到反射镜的距离
Figure PCTCN2020095940-appb-000007
即距离L2为前述图2中P3至P4点对应距离(或称腔长)，P4点与P3点在纵轴上的值相同，显然该距离L2只有端点P3处于线性区域中，或者说基本不属于线性区域。
若该基准光栅A与反射镜的距离L1不处于线性区域内，则与该基准光栅A相邻的光栅B与反射镜的距离L2处于线性区域内。在第一种情况下下，L1和L2满足：
Figure PCTCN2020095940-appb-000008
Figure PCTCN2020095940-appb-000009
其中，m为非负整数，即0、1、2...。
则，在第一种情况下，L2的范围变形为：
Figure PCTCN2020095940-appb-000010
参考图2可以看出，距离L处于线性区域内。
例如，假设m＝1，则L2为图2中P5至P6点对应距离，由于P5至P6点之间的区域与P2至P3点之间的区域的位置对应点的斜率一致，因此，光栅B与反射镜的距离L2处于线性区域内。其中，位置对应点指的是两个点在纵轴上的值相等。
在第二种情况下，L1和L2满足：
Figure PCTCN2020095940-appb-000011
Figure PCTCN2020095940-appb-000012
其中，p为正整数，即1、2...，m为非负整数，即0、1、2...。
在第二种情况下，L2的范围变形为：
Figure PCTCN2020095940-appb-000013
参考图2可以看出，距离L2处于线性区域内。
例如，假设该基准光栅A与反射镜的距离为前述图2中P3至P4点对应距离，光栅B与该基准光栅A到反射镜的距离之差g为3λ/8，即，p＝4，m＝1，则，
Figure PCTCN2020095940-appb-000014
光栅B到反射镜的距离L2为前述图2中P7至P8点对应距离，由于P7点至P8点之间的区域与P1至P3点之间的区域的位置对应点的斜率一致，因此，光栅B与反射镜的距离L2处于线性区域内。其中，位置对应点指的是两个点在纵轴上的值相等。
由上述原理可知，无论光栅组中任一光栅与反射镜之间的距离为多少，基于前述距离差设置光栅组中的光栅，可以保证：无论任一时刻，均至少有一个光栅与振膜的距离处于线性区域。而只要有一个光栅与振膜的距离处于线性区域，即可保证麦克风芯片工作在线性工作区，因此，所述多个光栅中至少两个光栅到反射镜的距离之差g为λ/8的奇数倍可以保证麦克风芯片始终工作于线性工作区。
示例的，假设光发射器发出的光的波长为λ＝850nm(纳米)，为了使麦克风处于线性工作区，所述多个光栅中至少两个光栅到反射镜的距离之差g最小可以取λ/8≈106.3nm，g值也可以取318.8nm(3λ/8)或531.3nm(5λ/8)等。
进一步的，在振膜振动过程中，即使一个光栅与反射镜的距离不处于线性区域中，还存在其他光栅与反射镜的距离处于线性区域中。相当于光栅之间起到了相互补偿的作用。并且，在装配完成后，可以对麦克风芯片进行简单调试，例如调试光栅组与反射镜的距离，然后对该麦克风芯片进行简单检测，即可实现麦克风芯片处于线性工作区，装配、调试和检测过程均较为简便。
提高麦克风芯片的探测灵敏度可以有效提高麦克风芯片的信噪比，而提高麦克风芯片的探测灵敏度的一个主要措施是使得麦克风芯片处于线性工作区。传统的麦克风芯片，通过驱动结构和相应的驱动控制电路控制振膜，使得反射镜和光栅的距离位于线性区域，这样的调节复杂度较高，而本申请实施例通过将光栅替换为光栅组，在简化结构的基础上，降低了制 造工艺难度，并保证了麦克风芯片稳定地处于线性工作区。从而提高麦克风探测灵敏度，以及信噪比。
图3和图4分别为本申请实施例提供的两种光栅组的俯视示意图。光栅是由大量平行狭缝131构成的光学元件，这些狭缝131是由多个平行排列的栅条132形成，其中，每两个相邻的栅条形成一条狭缝131。在本申请实施例中，光栅的狭缝131可以等宽等间距(该间距即栅条的宽度)，也可以不等宽和/或不等间距。该光栅组的边界形状也可以有多种，只要保证光栅组的正常的衍射和相位干涉功能即可。其中，光栅组的边界形状指的是光栅组在基板上的正投影的边缘所围成的形状，也即是光栅组被俯视时的边界形状。图3所示的光栅组的边界形状为矩形，图4所示的光栅组的边界形状为圆形。可选地，光栅组的边界形状还可以为椭圆形、梯形或者三角形或者其他不规则形状。考虑到光发射器投射的光斑通常是圆形的。在光栅组的边界面积略大于或等于投射光斑面积情况下，当光栅组的边界形状为圆形或圆弧形时，这样的光栅组相对于边界形状为其他形状的光栅组，对光的衍射效果相差不大，但是光栅组整体面积减小，占用空间面积较小，能够保证麦克风芯片的小型化。
可选地，光栅中栅条的长度可相等，也可以不相等。以前述图3和图4为例，图3中的光栅中栅条的长度相等，图4中的光栅中栅条的长度不相等。每个栅条的截面可以呈矩形、三角形、锯齿形或不规则形状等，为了便于说明，后续实施例均以每个栅条132的截呈矩形为例进行说明，例如，参见图5，图5是图3或图4所示的光栅组的A-A截面示意图，图5中，每个栅条132的截呈矩形为例进行说明。值得说明的是，在图5中，双光栅的光栅组，采用“左高右低”的实现方式，实际上，也可以采取“左低右高”实现方式。
进一步的，光栅组中不同光栅的形状和/或尺寸可以相同也可以不同。本申请实施例对此不做限定。其中，当光栅组中的光栅的形状和/或尺寸相同时，可以减少制造工艺的难度和复杂度。
本申请实施例中的光栅组可以由多个光栅以多种形式组合得到，只要保证所述多个光栅中至少两个光栅到反射镜的距离之差满足前述差值公式即可。则请参考图5至图15，图5至图15为本申请实施例提供的几种示例性光栅组的结构，其中，图5是光栅组包括2个光栅(即光栅组为双光栅结构)时的结构示意图；图6至图9是光栅组包括3个光栅(即光栅组为三光栅结构)时的结构示意图；图10至图12是光栅组包括4个光栅(即光栅组为四光栅结构)时的结构示意图；图13至图15是光栅组包括5个光栅(即光栅组为五光栅结构)时的结构示意图。图5至图15中的任一种结构示意图均可以为前述图3或图4所示的光栅组的A-A截面图。值得说明的是，本申请实施例中的光栅组可以是基于具有距离差的双光栅结构在光栅截面(即前述A-A截面)进行一次或多次轴对称、中心对称、角度旋转等操作后的变形结构。光栅组还可以包括6个光栅或者7个光栅等，其截面形状还可以为其他形状。本申请实施例对此不再赘述。
值得说明的是，图5至图15各个光栅的栅条的疏密程度，以及栅条的条数只是示意性绘制，本申请实施例并不对此进行限制。
本申请实施例中光栅组可以通过多种方式固定在基板和振膜之间，下面以以下两种实现方式为例进行说明：
在第一种实现方式中，光栅组通过光栅基底固定在基板和振膜之间。如图1以及图16至图21所示，麦克风芯片1还包括：
位于基板11和振膜12之间的光栅基底16，该光栅基底16用于布置光栅组，并透过光发射器14发射的光，该光栅基底16可以与基板平行设置；支撑结构17，该支撑结构17固定于基板11和振膜12之间，光栅基底16与支撑结构17固定连接。
其中，光栅基底16的形状可以有多种，例如图1、图17至图21所示的台阶状或图16所示的板状，只要保证有效固定光栅组，并使得固定的光栅组中光栅之间存在前述距离差即可。其中，采用板状光栅基底来固定光栅组，可以简化光栅基底的制造难度，降低制造成本。
该光栅基底的材质需要与发射器发射的光匹配，以保证透过光发射器14发射的光。示例的，若发射器34发射的光为可见光，光栅基底16可以采用透明材质制成，例如透明塑料、玻璃或者石英等。若发射器34发射的光为红外光，光栅基底16可以采用能够透射红外光的滤光片(即该滤光片用于滤除除红外光之外的其他光)制作。
光栅组可以通过在光栅基底上直接制作、粘贴或者转印等方式固定在光栅基底上。在本申请实施例中，光栅组中的光栅可以根据情况固定在光栅基底16的至少一侧，光发射器14和光探测器15的位置也可以相应调整。本申请实施例以以下几种可选方式为例对光栅组中光栅的布置方式进行说明：
在第一种可选方式中，如图1和图17至图21所示，光栅组的多个光栅13布置在光栅基底16的靠近振膜12的一侧。
在第二种可选方式中，如图20所示，光栅组的多个光栅13布置在光栅基底16的远离振膜12的一侧。
在第三种可选方式中，如图16所示，光栅组的多个光栅13布置在光栅基底16的靠近振膜12的一侧和远离振膜12的一侧。也即是光栅组中一部分光栅13布置在光栅基底16的靠近振膜12的一侧，另一部分光栅13布置在光栅基底16的靠近振膜12的一侧。
在前述三种可选方式中，光发射器14和光探测器15位于基板11上。
以图17至19为例，对本申请实施例提供的麦克风芯片的工作原理进行说明：当声压作用在振膜上，振膜12发生形变，带动振膜12下方的反射镜121向上或向下移动，光发射器14发出的光，一部分在光栅13下表面发生反射，一部分透过光栅狭缝透射到反射镜121，被反射镜121再次反射到光栅13上表面，这样具有光程差的光通过光栅13发生衍射以及相位干涉，通过光探测器15接收光栅的衍射光后，将光信号转化为电信号，并将电信号传输至后续的处理芯片，由该处理芯片进行信号解调。
在第四种可选方式中，如图21所示，光栅组的多个光栅13位于光栅基底16的靠近振膜12的一侧；光发射器14和光探测器15位于光栅基底16的远离振膜12的一侧。也即是光栅组以及光发射器14和光探测器15分别位于光栅基底16的两侧，且光发射器14和光探测器15在光栅基底16的同一侧。这样光发射器14发出的光仅需经过光栅基底16即可到达光栅，光发射器14与光栅基底16之间的距离较短。在保证光发射器14发散角的前提下，器件的布置更紧凑，可以减少基板11到光发射器14和光探测器15的距离，以减少麦克风芯片的整体厚度，实现麦克风芯片的小型化。
第四种可选方式中的麦克风芯片的原理可以参考前述三种可选方式的工作原理，本申请实施例对此不再赘述。
本申请实施例中，该支撑结构17可以有多种实现方式，只要保证将光栅基底16有效固定在基板11和振膜12之间即可。
在第一种可选实现方式中，支撑结构17可以包括多个柱状结构，如隔垫物(Photo Spacer，PS)，每个柱状结构的两端(即两个平行的表面所在端)分别与基板11和振膜12固定连接。该多个柱状结构可以绕基板11和振膜12边缘均匀分布，实现对基板11和振膜12的有效支撑。
在第二种可选实现方式中，支撑结构17为环形结构，即其俯视形状呈环形，支撑结构17的两端分别与基板11和振膜12固定连接。该支撑结构17可以绕基板11和振膜12边缘分布，与基板11和振膜12围成用于放置光栅组、光发射器和光探测器的腔体，实现对基板11和振膜12的有效支撑。该腔体为封闭腔体，可以阻挡外界灰尘，提高麦克风芯片的使用寿命。示例的，该支撑结构可以采用封框胶制成。
需要说明的是，该支撑结构还可以为其他用于支撑的结构，例如镂空的支撑架(可以实现麦克风芯片的良好散热)等，本申请对此不做限定。
本申请实施例中，光栅基底16在支撑结构17上的固定方式也可以有多种。
在一种可选实现方式中，如图16所示，支撑结构17的侧面具有卡接口，光栅基底16的边缘可以插入该卡接口，以与支撑结构17固定连接。示例的，支撑结构17上可以具有多个卡接口，该多个卡接口与支撑结构17的至少两侧(例如支撑结构17水平放置时的前后左右四侧中的至少两侧)对应，以使光栅基底16更为稳固地卡接在支撑结构17上。例如，若支撑结构17为前述第一种可选实现方式中的支撑结构时，多个柱状结构中的一个或多个柱状结构的朝向光栅基底的侧面设置该卡接口；若支撑结构17为前述第二种可选实现方式中的支撑结构时，支撑结构17的一个或多个内表面设置该卡接口。
在另一种可选实现方式中，如图17所示，支撑结构17由上支撑件171和下支撑件172两部分组成，光栅基底16的边缘可以卡接在上支撑件171和下支撑件172之间，以与支撑结构17固定连接。例如，若支撑结构17为前述第一种可选实现方式中的支撑结构时，多个柱状结构中每个柱状结构均分为上下两部分，前述上支撑件171由多个柱状结构的上部分组成，前述下支撑件172由多个柱状结构的下部分组成；若支撑结构17为前述第二种可选实现方式中的支撑结构时，支撑结构17分为上下两部分，上支撑件171即为支撑结构17的上部分，下支撑件172即为支撑结构17的下部分。
在又一种可选实现方式中，如图18所示，光栅基底16的边缘可以通过胶接(即胶水或者粘接剂连接)的方式与支撑结构17固定连接。
在第二种实现方式中，光栅组通过支撑结构固定在基板和振膜之间，如图22所示，麦克风芯片1还包括：
支撑结构17，支撑结构17固定于基板11和振膜12之间；每个光栅13固定在支撑结构17上。
该支撑结构17的结构和材质可以参考前述实施例中的支撑结构17的结构和材质，光栅13在支撑结构17上的固定方式，也可以参考前述实施例中光栅基底16在支撑结构17上的固定方式，本申请实施例不再赘述。该光栅组与支撑结构的固定连接可以通过微机械加工和微组装工艺来实现。
在一种可选示例中，当采用光栅基底承载光栅组时，光栅组的结构可以如图3和图4所示，每个光栅的各个栅条均可以间隔设置，互相之间不连接。而当不再设置光栅基底后，光栅组中每个光栅的结构可以如图23和图24所示，该光栅除了狭缝131和栅条132之外，还 包括与各个栅条132连接的连接条133，该连接条133可以为线形连接条，也可以为非线形连接条，如曲线连接条，通过该连接条133可以保证光栅中的各个栅条连接，起到对栅条的固定作用。当采用前述图19或图20所示的固定方式将光栅13固定在支撑结构17上，可以至少将连接条133所在侧与支撑结构17固定。图23和图24均以光栅组包括2个光栅为例进行说明，但并不对光栅组中光栅的个数进行限定。并且，图23和图24所示的光栅组以及类似的光栅组的A-A截面示意图仍然可以参考前述图5至图15，本申请实施例不再赘述。
在另一种可选示例中，每个光栅可以通过在如玻璃片等透明片状结构上刻蚀(例如激光刻蚀)出多个平行刻痕制成，该刻痕即为前述狭缝，每两个刻痕之间即为前述栅条，这样每个光栅实际为一个带有刻痕的片状结构，可以采用前述光栅基底16在支撑结构17上的固定方式，固定在支撑结构17上。
需要说明的是，在前述第一种实现方式中，光栅基底由于空气阻尼现象，会引入机械噪声。其中，空气阻尼现象指的是由于存在空气阻力，造成器件的机械谐振运动的振幅逐步减小的物理现象。
而在第二种实现方式中，通过将光栅直接与支撑结构固定，无需设置光栅基底，光栅类似于悬浮在振膜和基板之间，从而减少麦克风芯片的厚度，实现芯片小型化，并且由于未设置光栅基底，因此可以避免光栅基底与空气的相互作用，从而减少了空气阻尼现象所带来的噪声。
进一步可选地，如图17至图21所示，光栅基底16具有第一开孔161。请参考图25，图25是一种光栅基底16的俯视结构示意图。光栅基底16具有一个或多个该第一开孔161。当光栅基底16具有多个第一开孔161时，该多个第一开孔161的形状和/或尺寸(或面积)可以相同也可以不同。示例的，多个第一开孔161的形状可以包括圆形、矩形、蜂窝状(即正六边形)、三角形、椭圆形或其他不规则形状中的一种或多种，图25中，以第一开孔161包括圆形和不规则条状两种类型的开孔为例进行说明，但本申请实施例并不对第一开孔的形状进行限定。
由于第一开孔的个数越多，尺寸越大，光栅基底16与空气的相互作用越小，空气阻尼现象相应减弱。因此，可以在保证光栅基底16对光栅组有效承载的前提下，尽量设置更多以及尺寸更大的第一开孔。进一步的，该多个第一开孔161可以在光栅基底上均匀分布，例如呈中心对称或轴对称分布，这样可以保证光栅基底受力均匀，提高光栅基底的寿命。
值得说明的是，光栅基底的边界(即光栅基底在基板上正投影的边界)的形状和/或尺寸需要与光栅组匹配，以实现对光栅组的有效承载。示例的，光栅基底的形状可以与光栅组边界形状相同，例如，当光栅组的边界形状如图4所示时，光栅基底的边界形状如图25所示，两者的形状均为圆形。光栅基底的边界尺寸可以大于或等于光栅组的边界尺寸，以保证光栅组在基板上正投影所在区域位于光栅基底在基板上正投影所在区域中。例如，光栅基底的边界和光栅组的边界呈圆形时，光栅基底对应的圆形的直径大于光栅组对应的圆形的直径。
可选地，如图18至图22所示，振膜12上具有第二开孔122，以减少空气阻尼现象所带来的噪声。请参考图26，图26是一种振膜12的俯视结构示意图。
振膜12具有一个或多个该第二开孔122。当振膜12具有多个第二开孔122时，该多个第二开孔122的形状和/或尺寸(或面积)可以相同也可以不同。示例的，多个第二开孔122的形状可以包括圆形、矩形、三角形、椭圆形或其他不规则形状中的一种或多种，图26中， 以第二开孔122包括圆形的开孔为例进行说明，但本申请实施例并不对第二开孔的形状进行限定。
由于第二开孔的个数越多，尺寸越大，振膜12与空气的相互作用越小，空气阻尼现象相应减弱。因此，可以在保证振膜12对反射镜有效固定的前提下，尽量设置更多以及尺寸更大的第二开孔。进一步的，该多个第二开孔122可以在振膜12上均匀分布，例如呈中心对称或轴对称分布，这样可以保证振膜12受力均匀，提高振膜12的寿命。由于反射镜通常位于振膜12的中部，因此第二开孔122通常分布在振膜12的边缘。
示例的，振膜12上设置有多个第二开孔122时，至少两个第二开孔122的尺寸不同；和/或，至少两个第二开孔122的形状不同。该多个第二开孔122的尺寸和形状可以通过仿真软件经过模拟得到，也可以根据专家的经验设置，还可以根据实际需要或理论计算得到。
传统的麦克风芯片的振膜并不开孔，如果振膜不开孔，随着大气压力的升高，麦克风芯片的灵敏度会变差，并且在于腔内和腔外压力差过大时容易导致麦克风芯片损坏。本申请实施例在振膜上开孔，一方面减小空气阻尼，降低机械噪声，提高麦克风信噪比，另一方面使腔内外气压相通，也可在一定程度上释放振膜的应力。
另外，由于振膜12的厚度通常较薄，可以基于微穿孔吸声理论在振膜12上设置第二开孔122，以实现振膜的吸声效应。
其中，微穿孔吸声理论指的是在厚度小于1.0mm(毫米)的薄膜(或板状结构)上设置直径小于1.0mm的微孔(也称微穿孔)，开孔率(即开孔面积之和占薄膜整体面积的比例)通常为1％至5％，也即是振膜上第二开孔的总面积占振膜总面积的1％至5％，在薄膜一侧预留一定厚度(例如5-20cm(厘米))的空气层，从而形成微穿孔吸声结构，该结构为一具有吸声特性的共振高声阻结构。
根据微穿孔吸声理论，在振膜上开孔，如果开孔得到的第二开孔的数目和直径适当，形成的第二开孔即相当于前述微孔，对高频声音有吸声效应。第二开孔的尺寸越小，吸收的频率越高。这样可以有效滤除麦克风芯片所处环境中的高频噪声。
示例的，振膜上第二开孔的尺寸范围可以是1-200um(微米)。当振膜上具有多个第二开孔时，不同尺寸的第二开孔组合可以增加吸收的频率的宽度(也称吸声带宽)，实现多种频率的高频噪声的滤除，从而扩大滤除噪声的范围。通过在振膜上设置第二开孔来形成吸声效应，是一种有效降噪手段，能够提高麦克风芯片的灵敏度、信噪比和动态范围。
例如，假设采用该麦克风传感器来拾取人声，而人声频率范围为20Hz(赫兹)～20kHz(千赫兹)，因此需要滤除的是高于20kHz的噪声。则可以设置直径为10um或20um的固定直径的多个第二开孔来实现高于20kHz的噪声的滤除。进一步的，还可以采用直径范围在10um～20um的多种直径组合的多个第二开孔来实现高于20kHz的噪声的滤除，如10um和20um直径的第二开孔组合，这样振膜的吸声带宽大大增加，高频吸声的效果会更好。
在本申请实施例中，振膜12的形状可以为圆形、矩形、三角形或其他不规则形状等多种形状，只要能够产生微小形变，以实现麦克风芯片的拾音性能即可。
示例的，振膜12为圆形振膜。当振膜的形状为圆形时，这样的振膜相对于形状为其他形状的振膜，占用空间面积较小，能够保证麦克风芯片的小型化。并且，圆形振膜在受力时，其周围的应力均匀，不容易发生破裂，使用寿命较长，可以保证麦克风芯片性能的稳定性。
进一步可选地，如图22所示，当光栅13包括多个狭缝和环绕该多个狭缝的周边区域时， 该周边区域上可以具有第三开孔，以减少空气阻尼现象所带来的噪声。该周边区域为位于光栅边缘的不影响光栅的衍射和相位干涉功能的区域。例如，在一些场景中，如光栅为图23或图24所示的光栅组中的光栅，光栅包括连接条时，该周边区域为连接条133所在区域，则可以在连接条133上设置第三开孔，或者，光栅通过在如玻璃片等透明片状结构上刻蚀刻痕得到，则周边区域为该透明片状结构上环绕该多个刻痕的外围区域，可以在该外围设置第三开孔。当麦克风芯片设置有带有第一开孔的光栅基底时，则部分或全部第三开孔可以和第一开孔连通，以减少光栅对第一开孔的阻挡。需要说明的是，在另一些场景中，光栅本身尺寸就比较小，也即是光栅没有或者基本没有周边区域，如图3和图4所示的光栅组中的光栅，则无需设置该光栅开孔。
当光栅13具有多个第三开孔时，该多个第三开孔的形状和/或尺寸(或面积)可以相同也可以不同。示例的，多个第三开孔的形状可以包括圆形、矩形、三角形、椭圆形或其他不规则形状中的一种或多种，第三开孔的形状可以参考前述第一开孔和第三开孔的形状。示例的，该光栅13的俯视结构图可以参考图25中光栅基底的俯视结构示意图。
同理地，由于第三开孔的个数越多，尺寸越大，光栅13与空气的相互作用越小，空气阻尼现象相应减弱。因此，可以在保证光栅13自身性能的前提下，尽量设置更多以及尺寸更大的第三开孔。
本申请实施例中，一个光栅的衍射光强与衍射级数的关系参见图27，横轴表示衍射能量的级数，纵轴表示归一化的衍射光强。基于光栅衍射理论可知，当反射镜与某一光栅的距离为λ/4的奇数倍时，经由反射镜和该某一光栅的上反射面的衍射光将产生的相位差为π/2，参考图27中实线曲线，衍射图形的衍射能量主要集中在±1级；当反射镜与某一光栅的距离为λ/4的偶数倍时，经由反射镜和该某一光栅的上反射面的衍射光将产生的相位差为0，参考图27中虚线曲线，衍射图形的衍射能量主要集中0级，±1级处的光强为0。需要说明的是，前述光栅组相当于一个特殊光栅，其衍射光强与衍射级数的关系曲线也可以参考图27。
由此可以看出，当每个光栅到反射镜的距离为λ/4的整数倍时，对于每个光栅，其衍射光强集中在0级(即最大光强出现在0级)或集中在±1级处(即最大光强出现在±1级)，则光栅组的衍射光强集中在0级和/或±1级处。当反射镜与某一光栅的距离不为λ/4的整数倍时，例如，当所述多个光栅中至少两个光栅到反射镜的距离之差g为λ/8的奇数倍时，衍射光强与衍射级数的关系曲线相当于是图27中的实线曲线和虚线曲线加权叠加所形成的曲线，衍射能量主要集中在0级和±1级，在一些情况下，衍射能量也会部分分布在±3级处。
本申请实施例中，光发射器和光探测器的个数和设置位置需要基于前述衍射光强与衍射级数的关系确定。在一种可选方式中，可以基于光发射器的位置、光发射器的发光角度、反射镜的位置和光栅组的位置中的一种或多种参数，采用光栅方程计算得到光接收器的目标位置；在另一种可选方式中，可以基于光发射器的位置、光发射器的发光角度、反射镜的位置和光栅组的位置中的一种或多种参数，采用仿真软件模拟得到光接收器的目标位置。当目标位置有至少一个时，将光探测器设置在一个或多个目标位置上。在该目标位置上的光强大于指定光强阈值，例如该指定光强阈值为0。通常该目标位置即为前述的-3级、-1级、0级、+1级和+3级对应位置。
其中，对于光栅组中的任一光栅，该光栅满足的光栅方程为：d(sinα+sinβ)＝cλ；其中，λ为前述光发射器发射的光的波长λ，d为该光栅的狭缝的间距，也称光栅常数，α为光 发射器发射的光在该光栅的入射角，β为光栅衍射角，c为整数，取值为0，±1，±2，……。
如图1、图16、图18、图20至图22所示，光发射器可以是一个；又如图17和图19所示，光发射器也可以是两个甚至多个。光发射器的波长可以是相同，也可以不同。同理，光接收器可以是一个，也可以是两个、三个(如图1、图16、图18至图22所示)、四个、五个或六个(图17)等。
在一种示例中，如图18或图22所示，麦克风芯片包括1个光发射器14和3个光探测器15；其中，3个光探测器15分别用于接收光栅组衍射的-1级、0级和+1级的衍射光。这样能够在衍射能量集中的0级和±1级进行光强检测时，光强检测灵敏度较高。采用图18或图22所示的光发射器和光探测器的组合可以有效适配该应用场景。
在另一种示例中，如图17所示，麦克风芯片包括2个光发射器14和6个光探测器15；6个光探测器15分别用于接收光栅组衍射的-3级、-1级、0级、0级、+1级和+3级的衍射光。
在又一种示例中，麦克风芯片包括2个光发射器14和5个光探测器15；5个光探测器15分别用于接收光栅组衍射的-3级、-1级、0级、+1级和+3级的衍射光。
本申请实施例中，当采用两个光发射器和多个光接收器，可以提高衍射光强的接收效果，提高探测灵敏度。
根据光栅衍射理论以及图27可知，±5级及以后的衍射光强非常弱，通常一般最多采用光探测器对0级、±1级、±3级的衍射光强进行接收。以节约麦克风芯片的制造成本。
本申请实施例中，前述光发射器发射的光的波长λ在不同应用场景中可以有不同的定义。在一种情况下，当麦克风芯片包括一个光发射器，该光发射器发射的光的波长λ等于该一个光发射器发射的光的波长；在另一种情况下，当麦克风芯片包括多个光发射器，该多个光发射器发射的光的波长相等，则该光发射器发射的光的波长λ等于该多个光发射器中任一光发射器发射的光的波长；在又一种情况下，当麦克风芯片包括多个光发射器，该多个光发射器发射的光的波长有多种，则该光发射器发射的光的波长λ等于该多种波长的合成波长。
假设该个发射器发射的光有k种波长，分别为λ 1至λ k，k为大于1的整数。光发射器发射的光的波长λ满足合成波长公式：
Figure PCTCN2020095940-appb-000015
其中，max表示求最大值，i≠j，i∈[1,k]，j∈[1,k]。
也即是，合成波长λ为这k种波长中每两个波长的合成波长中的最大值。
示例的，当麦克风芯片包括2个光发射器14，其中，2个光发射器14发射的光的波长分别为λ 1和λ 2，两个波长不同；则λ满足波长公式：
Figure PCTCN2020095940-appb-000016
双波长的检测范围，从单波长的λ 1/4或λ 2/4提高到λ/4，最大检测灵敏度是在h＝λ/8，h为反射镜到光栅的距离。通过设置两种波长可以避开检测灵敏度低的检测点，扩大麦克风芯片的线性工作区，在一定范围内增大麦克风芯片的测量量程。
并且，当两个发光波长不同的光发射器的波长接近时，例如λ 1和λ 2的差值小于1，则通过上述波长公式，得到了一个更大的合成波长λ。通常一个光发射器发出的光的波长越大，其制造成本较高，而采用波长较小的两个光发射器来实现较大的合成波长λ，无需直接设置波长较大的光发射器，可以降低麦克风芯片的制造成本。
值得说明的是，本申请实施例中的附图16至图22等为麦克风芯片的截面图，图中存在光发射器和光探测器部署在同一水平方向上的情况，但是实质上光发射器和光探测器位置稍有错开，并不相互重叠，也不会产生相互阻挡。例如光发射器的俯视形状为回字形(即环状)，其环绕光探测器设置，或者光发射器和光探测器紧邻设置，图中只是示意性绘制，本申请实施例对此不做限定。
可选地，如图28所示，麦克风芯片1还包括：
控制电路18，该控制电路18可以与光发射器14电连接，用于控制光发射器14发光。示例的，该控制电路18可以位于基板11上。
进一步的，该麦克风芯片1还可以包括驱动电路，该驱动电路可以与光发射器14电连接，用于驱动光发射器14发光。该驱动电路可以位于基板11上。
进一步的，该麦克风芯片1还可以包括接收电路，该接收电路可以与光探测器15电连接，用于接收光探测器15输出的信号。该接收电路可以位于基板11上。
值得说明的是，该麦克风芯片中还可以基于具体功能，设置其他光学元件，用于调整光路，例如反射镜或棱镜等等。
综上所述，本申请实施例提供的麦克风芯片，所述多个光栅中至少两个光栅到反射镜的距离不同，因此，无需设置驱动结构以及驱动控制电路，即可实现反射镜与光栅距离的变化，不仅结构简单，还由于减少了驱动结构以及驱动控制电路的设置，而降低了制造工艺的难度和复杂度，减少了机械噪声和电路噪声。从而有效提高了麦克风芯片的拾音性能。
当所述多个光栅中至少两个光栅到反射镜的距离之差g为λ/8的奇数倍时，在简化结构的基础上，降低了制造工艺难度，并保证了麦克风芯片稳定地处于线性工作区。从而提高麦克风探测灵敏度和信噪比。
本申请实施例提供一种麦克风，如图29所示，包括：本申请前述任一实施例提供的麦克风芯片1，以及麦克风芯片1的封装结构2。
进一步可选的，该麦克风还可以包括主板3，该麦克风芯片1和封装结构2均设置在主板上。
示例的，该封装结构2可以为壳体，该封装结构2上具有入声孔21，以便于声音信号经过该入声孔21，通过壳体内部传入麦克风芯片1。
该麦克风还可以包括处理芯片4、以及处理芯片的封装体5，用于向处理芯片4导入信号的信号导入连接点(pad)61和用于从处理芯片4导出信号的信号导出连接点62。该封装体5可以为绝缘胶水。麦克风芯片1与处理芯片4通过信号线71电连接，处理芯片4与信号导入连接点61通过信号线72电连接。示例的，处理芯片4可以为专用集成电路(Application Specific Integrated Circuit，ASIC)芯片。
其中，主板可以为PCB。麦克风芯片1的基板可以与该主板为一体结构，也即是，基板就是该主板。该入声孔21与麦克风芯片1错开，也即是入声孔21在主板上的正投影和麦克风芯片1在主板上的正投影不重叠，这样可以避免外界环境的污染物进入麦克风芯片中，提高麦克风芯片的使用寿命。
值得说明的是，该麦克风中还可以基于具体功能，在麦克风芯片外设置其他光学元件，用于调整光路，例如反射镜或棱镜等等。
本申请实施例提供的麦克风可以作为单独的麦克风使用，也可以应用于智能音响、自动驾驶、人机交互等物联网、车联网、机器人等领域需要长距离高保真拾取人声的场景。采用本申请实施例提供的麦克风，可以有效提高光学麦克风的探测灵敏度，以此提高光学麦克风的信噪比和动态范围等性能。
本申请实施例提供一种终端设备，包括本申请上述实施例提供的麦克风。示例的，该终端设备可以为智能音响、自动驾驶、人机交互等物联网、车联网或机器人等。
图30示出了本申请一个示例性实施例提供的终端设备3000的结构框图。该终端设备3000可以是：智能手机、平板电脑、MP3播放器(Moving Picture Experts Group Audio Layer III，动态影像专家压缩标准音频层面3)、MP4(Moving Picture Experts Group Audio Layer IV，动态影像专家压缩标准音频层面4)播放器、笔记本电脑或台式电脑。终端设备3000还可能被称为用户设备、便携式终端设备、膝上型终端设备、台式终端等其他名称。
通常，终端设备3000包括有：处理器3001和存储器3002。
处理器3001可以包括一个或多个处理核心，比如4核心处理器、8核心处理器等。处理器3001可以采用DSP(Digital Signal Processing，数字信号处理)、FPGA(Field－Programmable Gate Array，现场可编程门阵列)、PLA(Programmable Logic Array，可编程逻辑阵列)中的至少一种硬件形式来实现。处理器3001也可以包括主处理器和协处理器，主处理器是用于对在唤醒状态下的数据进行处理的处理器，也称CPU(Central Processing Unit，中央处理器)；协处理器是用于对在待机状态下的数据进行处理的低功耗处理器。在一些实施例中，处理器3001可以在集成有GPU(Graphics Processing Unit，图像处理器)，GPU用于负责显示屏所需要显示的内容的渲染和绘制。一些实施例中，处理器3001还可以包括AI(Artificial Intelligence，人工智能)处理器，该AI处理器用于处理有关机器学习的计算操作。
存储器3002可以包括一个或多个计算机可读存储介质，该计算机可读存储介质可以是非暂态的。存储器3002还可包括高速随机存取存储器，以及非易失性存储器，比如一个或多个磁盘存储设备、闪存存储设备。在一些实施例中，存储器3002中的非暂态的计算机可读存储介质用于存储至少一个指令。
在一些实施例中，终端设备3000还可选包括有：外围设备接口3003和至少一个外围设备。处理器3001、存储器3002和外围设备接口3003之间可以通过总线或信号线相连。各个外围设备可以通过总线、信号线或电路板与外围设备接口3003相连。具体地，外围设备包括：射频电路3004、触摸显示屏3005、摄像头3006、音频电路3007、定位组件3008和电源3009中的至少一种。
外围设备接口3003可被用于将I/O(Input/Output，输入/输出)相关的至少一个外围设备连接到处理器3001和存储器3002。在一些实施例中，处理器3001、存储器3002和外围设备接口3003被集成在同一芯片或电路板上；在一些其他实施例中，处理器3001、存储器3002和外围设备接口3003中的任意一个或两个可以在单独的芯片或电路板上实现，本实施例对此不加以限定。
射频电路3004用于接收和发射RF(Radio Frequency，射频)信号，也称电磁信号。射频电路3004通过电磁信号与通信网络以及其他通信设备进行通信。射频电路3004将电信号转换为电磁信号进行发送，或者，将接收到的电磁信号转换为电信号。可选地，射频电路3004 包括：天线系统、RF收发器、一个或多个放大器、调谐器、振荡器、数字信号处理器、编解码芯片组、用户身份模块卡等等。射频电路3004可以通过至少一种无线通信协议来与其它终端设备进行通信。该无线通信协议包括但不限于：城域网、各代移动通信网络(2G、3G、4G及5G)、无线局域网和/或WiFi(Wireless Fidelity，无线保真)网络。在一些实施例中，射频电路3004还可以包括NFC(Near Field Communication，近距离无线通信)有关的电路，本申请对此不加以限定。
显示屏3005用于显示UI(UserInterface，用户界面)。该UI可以包括图形、文本、图标、视频及其它们的任意组合。当显示屏3005是触摸显示屏时，显示屏3005还具有采集在显示屏3005的表面或表面上方的触摸信号的能力。该触摸信号可以作为控制信号输入至处理器3001进行处理。此时，显示屏3005还可以用于提供虚拟按钮和/或虚拟键盘，也称软按钮和/或软键盘。在一些实施例中，显示屏3005可以为一个，设置终端设备3000的前面板；在另一些实施例中，显示屏3005可以为至少两个，分别设置在终端设备3000的不同表面或呈折叠设计；在再一些实施例中，显示屏3005可以是柔性显示屏，设置在终端设备3000的弯曲表面上或折叠面上。甚至，显示屏3005还可以设置成非矩形的不规则图形，也即异形屏。显示屏3005可以采用LCD(Liquid Crystal Display，液晶显示屏)、OLED(Organic Light-Emitting Diode,有机发光二极管)等材质制备。
摄像头组件3006用于采集图像或视频。可选地，摄像头组件3006包括前置摄像头和后置摄像头。通常，前置摄像头设置在终端设备的前面板，后置摄像头设置在终端设备的背面。在一些实施例中，后置摄像头为至少两个，分别为主摄像头、景深摄像头、广角摄像头、长焦摄像头中的任意一种，以实现主摄像头和景深摄像头融合实现背景虚化功能、主摄像头和广角摄像头融合实现全景拍摄以及VR(Virtual Reality，虚拟现实)拍摄功能或者其它融合拍摄功能。在一些实施例中，摄像头组件3006还可以包括闪光灯。闪光灯可以是单色温闪光灯，也可以是双色温闪光灯。双色温闪光灯是指暖光闪光灯和冷光闪光灯的组合，可以用于不同色温下的光线补偿。
音频电路3007可以包括前述麦克风1和扬声器。麦克风1用于采集用户及环境的声波，并将声波转换为电信号输入至处理器3001，该处理器3001用于对接收的电信号进行处理，存储器3002可以对处理得到的数据进行存储，以实现对声波对应的数据的录制或存储等；或者麦克风1处理得到的电信号还可以输入至射频电路3004以实现语音通信。出于立体声采集或降噪的目的，麦克风可以为多个，分别设置在终端设备3000的不同部位。麦克风还可以是阵列麦克风或全向采集型麦克风。扬声器则用于将来自处理器3001或射频电路3004的电信号转换为声波。扬声器可以是传统的薄膜扬声器，也可以是压电陶瓷扬声器。当扬声器是压电陶瓷扬声器时，不仅可以将电信号转换为人类可听见的声波，也可以将电信号转换为人类听不见的声波以进行测距等用途。在一些实施例中，音频电路3007还可以包括耳机插孔。
定位组件3008用于定位终端设备3000的当前地理位置，以实现导航或LBS(Location Based Service，基于位置的服务)。定位组件3008可以是基于美国的GPS(Global Positioning System，全球定位系统)、中国的北斗系统、俄罗斯的格雷纳斯系统或欧盟的伽利略系统的定位组件。
电源3009用于为终端设备3000中的各个组件进行供电。电源3009可以是交流电、直流电、一次性电池或可充电电池。当电源3009包括可充电电池时，该可充电电池可以支持有线 充电或无线充电。该可充电电池还可以用于支持快充技术。
在一些实施例中，终端设备3000还包括有一个或多个传感器3010。该一个或多个传感器3010包括但不限于：加速度传感器3011、陀螺仪传感器3012、压力传感器3013、指纹传感器3014、光学传感器3015以及接近传感器3016。
加速度传感器3011可以检测以终端3000建立的坐标系的三个坐标轴上的加速度大小。比如，加速度传感器3011可以用于检测重力加速度在三个坐标轴上的分量。处理器3001可以根据加速度传感器3011采集的重力加速度信号，控制触摸显示屏3005以横向视图或纵向视图进行用户界面的显示。加速度传感器3011还可以用于游戏或者用户的运动数据的采集。
陀螺仪传感器3012可以检测终端设备3000的机体方向及转动角度，陀螺仪传感器3012可以与加速度传感器3011协同采集用户对终端设备3000的3D动作。处理器3001根据陀螺仪传感器3012采集的数据，可以实现如下功能：动作感应(比如根据用户的倾斜操作来改变UI)、拍摄时的图像稳定、游戏控制以及惯性导航。
压力传感器3013可以设置在终端设备3000的侧边框和/或触摸显示屏3005的下层。当压力传感器3013设置在终端设备3000的侧边框时，可以检测用户对终端设备3000的握持信号，由处理器3001根据压力传感器3013采集的握持信号进行左右手识别或快捷操作。当压力传感器3013设置在触摸显示屏3005的下层时，由处理器3001根据用户对触摸显示屏3005的压力操作，实现对UI界面上的可操作性控件进行控制。可操作性控件包括按钮控件、滚动条控件、图标控件、菜单控件中的至少一种。
指纹传感器3014用于采集用户的指纹，由处理器3001根据指纹传感器3014采集到的指纹识别用户的身份，或者，由指纹传感器3014根据采集到的指纹识别用户的身份。在识别出用户的身份为可信身份时，由处理器3001授权该用户执行相关的敏感操作，该敏感操作包括解锁屏幕、查看加密信息、下载软件、支付及更改设置等。指纹传感器3014可以被设置终端设备3000的正面、背面或侧面。当终端设备3000上设置有物理按键或厂商Logo时，指纹传感器3014可以与物理按键或厂商Logo集成在一起。
光学传感器3015用于采集环境光强度。在一个实施例中，处理器3001可以根据光学传感器3015采集的环境光强度，控制触摸显示屏3005的显示亮度。具体地，当环境光强度较高时，调高触摸显示屏3005的显示亮度；当环境光强度较低时，调低触摸显示屏3005的显示亮度。在另一个实施例中，处理器3001还可以根据光学传感器3015采集的环境光强度，动态调整摄像头组件3006的拍摄参数。
接近传感器3016，也称距离传感器，通常设置在终端设备3000的前面板。接近传感器3016用于采集用户与终端设备3000的正面之间的距离。在一个实施例中，当接近传感器3016检测到用户与终端设备3000的正面之间的距离逐渐变小时，由处理器3001控制触摸显示屏3005从亮屏状态切换为息屏状态；当接近传感器3016检测到用户与终端设备3000的正面之间的距离逐渐变大时，由处理器3001控制触摸显示屏3005从息屏状态切换为亮屏状态。
本领域技术人员可以理解，图12中示出的结构并不构成对终端设备3000的限定，可以包括比图示更多或更少的组件，或者组合某些组件，或者采用不同的组件布置。
根据本申请实施例要点和核心模块的构造思想，本申请实施例可以围绕光栅组的边界形状、光栅形状、光栅基底的材料、振膜形状、振膜材料、反射镜形状、反射镜材料、光栅的距离差、光发射器和光探测器等进行一定的组合，可以形成多种实现麦克风芯片的方案，以 得到多种实施例，例如：光栅组不仅仅局限于双光栅，也可以是具有一定三光栅、四光栅或五光栅等，只要保证光栅组与光发射器所发射的光斑形状匹配(例如光栅组能够在光探测器排布方向上覆盖光发射器的光斑)即可；振膜可以有孔、无孔、带不同直径的孔；光栅的栅条的截面形状可以是长方形，可以是三角形、锯齿形，还可以是不规则形状等。需要说明的是，在附图描述中，相似或相同的部分都使用相同的符号。附图中未绘示或描述的实现方式，为所属技术领域技术人员所知的形式。以上所述仅为本申请实施例具有代表性的具体实施例而已，并不用于限制本申请实施例，凡在本申请实施例的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请实施例的保护范围之内。
需要说明的是，为使本申请实施例的说明清晰，参考附图可能未显示不相关的部件，并且为了清晰，层和区域的厚度可能被夸大。当陈述一层在另一层或基底“上”时，该层可以直接在另一层或基底“上”，或者它们之间可以布置第三层。另外，虽然本申请实施例提供包含特定值的参数的示范，但应了解，参数无需确切等于相应的值，而是可在可接受的误差容限或设计约束内近似于相应的值。
本领域普通技术人员可以理解实现上述实施例的全部或部分步骤可以通过硬件来完成，也可以通过程序来指令相关的硬件完成，所述的程序可以存储于一种计算机可读存储介质中，上述提到的存储介质可以是只读存储器，磁盘或光盘等。
以上所述仅为本申请的可选实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (17)

  1. 一种麦克风芯片，其特征在于，所述麦克风芯片包括：
    相对的基板和振膜；
    位于所述振膜上靠近所述基板的一侧的反射镜；
    位于所述基板和振膜之间的光栅组；
    位于所述基板与所述光栅组之间的光发射器和光探测器；
    其中，所述光栅组包括多个光栅，所述多个光栅中至少两个光栅到所述反射镜的距离不同。
  2. 根据权利要求1所述的麦克风芯片，其特征在于，所述多个光栅中至少两个光栅到所述反射镜的距离之差g满足：
    (2n-1)λ/8-λ/16≤g≤(2n-1)λ/8+λ/16，所述λ为所述光发射器发射的光的波长，n为大于0的整数。
  3. 根据权利要求2所述的麦克风芯片，其特征在于，
    所述多个光栅中至少两个光栅到所述反射镜的距离之差g为λ/8的奇数倍，所述λ为所述光发射器发射的光的波长。
  4. 根据权利要求1至3中任一所述的麦克风芯片，其特征在于，所述麦克风芯片还包括：
    位于所述基板和振膜之间的光栅基底，所述光栅基底用于布置所述光栅组，并透过所述光发射器发射的光；
    支撑结构，所述支撑结构固定于所述基板和振膜之间，所述光栅基底与所述支撑结构固定连接。
  5. 根据权利要求4所述的麦克风芯片，其特征在于，所述光栅组的多个光栅布置在所述光栅基底的靠近所述振膜的一侧和/或远离所述振膜的一侧；
    所述光发射器和所述光探测器位于所述基板上。
  6. 根据权利要求4所述的麦克风芯片，其特征在于，
    所述光栅组的多个光栅位于所述光栅基底的靠近所述振膜的一侧；
    所述光发射器和所述光探测器位于所述光栅基底的远离所述振膜的一侧。
  7. 根据权利要求4至6中任一所述的麦克风芯片，其特征在于，
    所述光栅基底具有第一开孔。
  8. 根据权利要求1至3中任一所述的麦克风芯片，其特征在于，所述麦克风芯片还包括：
    支撑结构，所述支撑结构固定于所述基板和振膜之间；
    每个所述光栅固定在所述支撑结构上。
  9. 根据权利要求1至8中任一所述的麦克风芯片，其特征在于，
    所述振膜上具有第二开孔；
    和/或，所述光栅包括多个狭缝和环绕所述多个狭缝的周边区域，所述周边区域上具有第三开孔。
  10. 根据权利要求9所述的麦克风芯片，其特征在于，所述第二开孔的尺寸范围是1-200um；
    和/或，所述振膜上第二开孔的总面积占所述振膜总面积的1％至5％。
  11. 根据权利要求1至10中任一所述的麦克风芯片，其特征在于，
    所述振膜为圆形振膜。
  12. 根据权利要求1至11中任一所述的麦克风芯片，其特征在于，
    所述光栅组的边界形状为圆形或圆弧形。
  13. 根据权利要求2或3所述的麦克风芯片，其特征在于，所述麦克风芯片包括2个所述光发射器，其中，所述2个所述光发射器发射的光的波长分别为λ 1和λ 2；所述λ满足：
    Figure PCTCN2020095940-appb-100001
  14. 根据权利要求1至13中任一所述的麦克风芯片，其特征在于，所述麦克风芯片包括1个所述光发射器和3个所述光探测器，其中，所述3个所述光探测器分别用于接收所述光栅组衍射的-1级、0级和+1级的衍射光。
  15. 根据权利要求1至14中任一所述的麦克风芯片，其特征在于，所述麦克风芯片还包括：
    控制电路，所述控制电路用于控制所述光发射器发光。
  16. 一种麦克风，其特征在于，包括：权利要求1至15中任一所述的麦克风芯片，以及所述麦克风芯片的封装结构。
  17. 一种终端设备，其特征在于，包括处理器、存储器至少一个如权利要求1至15中任一所述的麦克风芯片，
    所述至少一个麦克风芯片用于采集声波，将声波转换成电信号输入至所述处理器；
    所述处理器，用于对声波转换成的电信号进行处理；
    所述存储器，用于存储所述处理器对所述电信号处理得到的数据。
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