WO2024051441A1 - Mems扬声器阵列 - Google Patents

Mems扬声器阵列 Download PDF

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Publication number
WO2024051441A1
WO2024051441A1 PCT/CN2023/112681 CN2023112681W WO2024051441A1 WO 2024051441 A1 WO2024051441 A1 WO 2024051441A1 CN 2023112681 W CN2023112681 W CN 2023112681W WO 2024051441 A1 WO2024051441 A1 WO 2024051441A1
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WO
WIPO (PCT)
Prior art keywords
diaphragm
diaphragm unit
speaker array
mems speaker
units
Prior art date
Application number
PCT/CN2023/112681
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English (en)
French (fr)
Inventor
张孟伦
孙铭超
庞慰
Original Assignee
天津大学
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Application filed by 天津大学 filed Critical 天津大学
Publication of WO2024051441A1 publication Critical patent/WO2024051441A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers

Definitions

  • the present application relates to the field of MEMS speakers, and in particular, to a MEMS speaker array.
  • MEMS Micro-Electro-Mechanical System
  • MEMS Micro-Electro-Mechanical System
  • CMOS complementary metal-oxide-semiconductor
  • embodiments of the present application provide a MEMS speaker array, which can improve the sound generation efficiency of the MEMS speaker array while ensuring that the MEMS speaker array has a sufficiently wide operating bandwidth.
  • Embodiments of the present application provide a MEMS speaker array, including a substrate and a diaphragm unit array arranged on the substrate. Sound holes are provided on the substrate.
  • the diaphragm unit array includes at least two diaphragm units arranged at intervals. , the diaphragm units are correspondingly arranged in the sound hole, and at least two diaphragm units have at least two different resonant frequencies.
  • the at least two diaphragm units include at least one first diaphragm unit and at least one second diaphragm unit, and the first diaphragm unit and the second diaphragm unit respectively have different resonant frequencies.
  • At least one of an acoustic damping component and a mechanical damping component is provided on the diaphragm unit.
  • a sound hole is provided on the base, and the diaphragm unit is correspondingly arranged in the sound hole.
  • the MEMS speaker array includes the acoustic damping component, and the acoustic damping component is arranged opposite to the sound hole.
  • the MEME speaker array includes the acoustic damping member, which is disposed on a side of the sound hole away from the diaphragm unit.
  • an acoustic damping member covers at least part of the diaphragm unit.
  • the acoustic damping member covers all surfaces of the diaphragm unit.
  • the acoustic damping component includes a damping net.
  • the acoustic damping member is a damping plate
  • the damping plate is provided with a plurality of through holes
  • the plurality of through holes are arranged opposite to the diaphragm unit.
  • the damping plate is a silicon plate.
  • a plurality of the through holes form at least two through hole arrays, and different through hole arrays are respectively arranged corresponding to the diaphragm units.
  • At least two of the through hole arrays include a first through hole array and a second through hole array, and the first through hole array and the second through hole array have different through holes.
  • the number and/or size of the through holes is such that the diaphragm units corresponding to the first through hole array and the second through hole array have different acoustic damping.
  • the mechanical damping component includes a mechanical damping layer covering at least part of the diaphragm unit, and the mechanical damping layer covers at least one of the diaphragm units.
  • the diaphragm unit and the hole wall of the sound hole together form a back cavity.
  • the diaphragm unit and the sound hole together form at least two back cavities, the at least two back cavities include a first back cavity, and the first back cavity corresponds to the Some of the diaphragm units in the diaphragm unit array.
  • the first back cavity corresponds to a single diaphragm unit in the diaphragm unit array.
  • each of the back cavities corresponds to different diaphragm units.
  • the at least two back cavities further include a second back cavity, and the third back cavity
  • the two back cavities correspond to at least two of the diaphragm units.
  • it also includes an upper cover, the upper cover is connected to the base, the upper cover is disposed on a side of the diaphragm unit away from the back cavity, and the upper cover and the diaphragm unit form at least one front cavity.
  • the number of the back cavities is at least two; and/or the number of the front cavities is at least two.
  • each front cavity corresponds to a different diaphragm unit.
  • the first diaphragm unit and the second diaphragm unit respectively have different shapes; and/or the first diaphragm unit and the second diaphragm unit respectively With different diaphragm coverage areas.
  • the type of the diaphragm unit includes at least one of a cantilever beam diaphragm unit and a fixed circular diaphragm unit.
  • a driver is further included, and the driver is configured to drive the diaphragm unit to couple with vibration.
  • the driver is arranged around the circumferential outside of the diaphragm unit, and the driver couples vibration with the diaphragm unit through a coupling structure.
  • the first diaphragm unit and the second diaphragm unit respectively have different diaphragm coverage areas; and/or the first diaphragm unit and the second diaphragm unit have different diaphragm coverage areas.
  • the membrane units respectively correspond to different free boundary lengths of the driver; and/or, the first diaphragm unit and the second diaphragm unit respectively have different shapes.
  • a mass block is also included.
  • the driver drives the diaphragm unit to couple vibration through the mass block, and the mass blocks corresponding to different diaphragm units have different masses.
  • the diaphragm units in the diaphragm unit array are arranged side by side at intervals along the same direction, and an air cavity is formed between each adjacent diaphragm unit.
  • Different diaphragms Units come in different sizes.
  • different diaphragm units have different thicknesses in the arrangement direction; and/or different diaphragm units have different extension dimensions in the length direction of the diaphragm unit, wherein, The length direction of the diaphragm unit and the arrangement direction of the diaphragm unit are perpendicular to each other.
  • the resonant frequencies of each of the diaphragm units in the diaphragm unit array increase sequentially, and among the diaphragm units arranged in order according to the resonant frequency, two adjacent ones
  • the vibration phase difference of the diaphragm unit is less than 180 degrees.
  • the vibration phase difference of two adjacent diaphragm units is less than 120 degrees.
  • the vibration phase difference of two adjacent diaphragm units is less than 90 degrees.
  • the number of input signal ports corresponding to the MEMS speaker array is smaller than the number of the diaphragm units.
  • the number of input signal ports corresponding to the MEMS speaker array is 1.
  • the vibration phase difference of different diaphragm units is greater than 120 degrees before adding at least one of the acoustic damping member and the mechanical damping member; the vibration phase difference of different diaphragm units is The phase difference is less than 120 degrees after adding at least one of the acoustic damping member and the mechanical damping member.
  • the vibration phase difference of different diaphragm units is greater than 90 degrees before adding at least one of the acoustic damping member and the mechanical damping member; the vibration phase difference of different diaphragm units is The phase difference is less than 90 degrees after adding at least one of the acoustic damping member and the mechanical damping member.
  • the MEMS speaker array provided by the embodiment of the present application includes a substrate and a diaphragm unit array arranged on the substrate.
  • the diaphragm unit array includes at least two diaphragm units arranged at intervals, and the at least two diaphragm units have at least two different diaphragm units. the resonant frequency.
  • multiple different resonant frequencies can cover a relatively wide operating bandwidth, thereby satisfying the operating bandwidth of the MEMS speaker array. Improve the sound efficiency of MEMS speaker arrays.
  • Figure 1A is a schematic top view of a MEMS speaker array provided by an embodiment of the present application.
  • Figure 1B is a schematic cross-sectional view at A-A in Figure 1A;
  • Figure 1C is a schematic bottom view of the MEMS speaker array provided by the embodiment of the present application.
  • Figure 1D is a schematic diagram of the damping net 50 covering part of the diaphragm unit in the embodiment of the present application;
  • Figure 1E is a schematic diagram of a driving method of the MEMS speaker array provided by the embodiment of the present application.
  • Figure 1F is a schematic diagram of another driving method of the MEMS speaker array provided by the embodiment of the present application.
  • Figure 1G is a simulation rendering of the frequency response of the phase difference to the sound pressure level in the MEMS speaker array provided by the embodiment of the present application;
  • Figure 2A is a schematic schematic diagram of a structure of a multi-resonant speaker provided by an embodiment of the present application
  • Figure 2B is a schematic diagram comparing the frequency response curves of the MEMS speaker array and the single resonant frequency speaker provided by the embodiment of the present application;
  • Figure 2C is a schematic diagram of experimental results when the resonant frequency is 2 in the MEMS speaker array provided by the embodiment of the present application;
  • Figure 3A is a schematic cross-sectional view of the cross-sectional structure at A-A in Figure 1A without applying a damping structure;
  • Figure 3B is a schematic cross-sectional view of the cross-sectional structure at A-A in Figure 1A with a damping structure applied but without an independent back cavity;
  • Figure 3C is a schematic diagram comparing the frequency response curves of the multi-resonant frequency MEMS speaker array with independent back cavity and acoustic damping provided by the embodiment of the present application and the structure of Figures 3A and 3B;
  • Figure 3D is a schematic diagram of another experimental result when the resonant frequency is 2 in the MEMS speaker array provided by the embodiment of the present application;
  • Figure 4A is a schematic structural diagram of the damping plate in the embodiment of the present application.
  • Figure 4B is another structural schematic diagram of the damping plate in the embodiment of the present application.
  • Figure 5 is a schematic cross-sectional view of a structure of a MEMS speaker array provided by an embodiment of the present application.
  • Figure 6 is a structural schematic diagram in which the damping structure is a mechanical damping component in the embodiment of the present application.
  • Figure 7 is a schematic structural diagram of applying a damping net on the basis of Figure 6;
  • Figure 8 is a schematic structural diagram of a part of the diaphragm unit covered by the mechanical damping member in the embodiment of the present application;
  • Figure 9 is a schematic structural diagram of at least two back cavities in an embodiment of the present application.
  • Figure 10A is a schematic structural diagram of a front cavity in an embodiment of the present application.
  • Figure 10B is another structural schematic diagram with a front cavity in the embodiment of the present application.
  • Figure 11A is a first structural schematic diagram of a diaphragm unit array provided by an embodiment of the present application.
  • Figure 11B is a second structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 12 is a third structural schematic diagram of a diaphragm unit array provided by an embodiment of the present application.
  • Figure 13 is a fourth structural schematic diagram of a diaphragm unit array provided by an embodiment of the present application.
  • Figure 14A is a fifth structural schematic diagram of a diaphragm unit array provided by an embodiment of the present application.
  • Figure 14B is a schematic cross-sectional view at B-B in Figure 14A;
  • Figure 15 is a sixth structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 16A is a seventh structural schematic diagram of a diaphragm unit array provided by an embodiment of the present application.
  • Figure 16B is a schematic structural diagram of the eighth diaphragm unit array provided by an embodiment of the present application.
  • Figure 16C is a ninth structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 16D is a tenth structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 17A is a schematic structural diagram of an eleventh diaphragm unit array provided by an embodiment of the present application.
  • Figure 17B is a schematic cross-sectional structural diagram at D-D in Figure 17A;
  • Figure 17C is a twelfth structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 18A is a thirteenth structural schematic diagram of the diaphragm unit array provided by the embodiment of the present application.
  • Figure 18B is a partially enlarged schematic view of E in Figure 18A;
  • Figure 18C is a schematic structural diagram of the damping plate and upper cover provided by the embodiment of the present application.
  • Figure 18D is another structural schematic diagram of the damping plate and upper cover provided by the embodiment of the present application.
  • Figure 19A is another structural schematic diagram of the damping plate and upper cover provided by the embodiment of the present application.
  • Figure 19B is another structural schematic diagram of the damping plate and upper cover provided by the embodiment of the present application.
  • Figure 20A is a schematic cross-sectional view of a structure of a diaphragm unit provided by an embodiment of the present application.
  • Figure 20B is a schematic cross-sectional view of another structure of the diaphragm unit provided by the embodiment of the present application.
  • FIG. 20C is another structural schematic diagram of a diaphragm unit provided by an embodiment of the present application.
  • the inventor of this application discovered during actual work that the MEMS diaphragm array can achieve very high energy conversion efficiency near the resonant frequency, thereby improving the sound generation efficiency of the MEMS diaphragm.
  • the sound generation efficiency of a single vibration unit in the MEMS diaphragm array The resonant frequency can only cover a very narrow bandwidth, while MEMS speakers require a wider operating bandwidth. Therefore, while improving the sound efficiency of MEMS speakers, there is a technical problem of being unable to meet the operating bandwidth of MEMS speakers.
  • embodiments of the present application provide a MEMS speaker.
  • Multiple diaphragm units are arranged to form an array, and the multiple diaphragm units have different resonant frequencies. In this way, multiple different resonant frequencies can make the MEMS speaker
  • the array covers a wide operating bandwidth, thereby improving the sound efficiency of the MEMS speaker array while meeting the operating bandwidth of the MEMS speaker array.
  • FIG. 1A is a schematic top view of a MEMS speaker array provided by an embodiment of the present application.
  • an embodiment of the present application provides a MEMS speaker array 100 , including: a substrate 23 and a diaphragm unit array arranged on the substrate 23 .
  • the base 23 can provide a supporting foundation for devices such as the diaphragm unit array disposed on the base 23 .
  • the substrate 23 can be made of crystalline semiconductor material.
  • the substrate 23 can be a silicon (Si) substrate.
  • the substrate 23 can also be a silicon germanium (SiGe) substrate or silicon carbide (SiC). substrate, silicon-on-insulator (SOI) substrate, etc.; in addition, the substrate 23 can be a single-layer structure or a multi-layer composite structure, and the specific adaptive design is based on actual needs, which will not be detailed here.
  • the substrate 23 is a silicon substrate as an example for introduction.
  • the diaphragm unit array includes at least two diaphragm units 10 arranged at intervals, and the at least two diaphragm units 10 have at least two different resonant frequencies.
  • the diaphragm unit array includes at least two diaphragm units 10 arranged at intervals, and by making at least two diaphragm units 10 have at least two different resonant frequencies, the resonance state of one diaphragm unit 10 is achieved. Afterwards, the resonance state of the next diaphragm unit 10 can be entered, so that the MEMS speaker array 100 can cover a wider operating bandwidth, and the diaphragm units 10 in the MEMS speaker array 100 can achieve higher energy near their respective resonant frequencies. conversion efficiency, thereby improving the sound generation efficiency of the MEMS speaker array 100.
  • the vibration unit is provided with driveable electrodes and/or functional materials (such as piezoelectric films, electromagnetic films, capacitive electrodes, etc.) to form different types of MEMS speakers (piezoelectric, electromagnetic, electrostatic, etc.).
  • driveable electrodes and/or functional materials such as piezoelectric films, electromagnetic films, capacitive electrodes, etc.
  • the at least two diaphragm units 10 include at least one first diaphragm unit 10 and at least one second diaphragm unit 10 , and the first diaphragm unit 10 and the second diaphragm unit 10 respectively have different resonances. frequency.
  • the MEMS speaker array 100 can cover the frequency band of 2 kHz to 10 kHz by setting 4 to 6 diaphragm units 10 with different resonant frequencies, or by setting 10 to 20 diaphragm units 10 with different resonant frequencies.
  • the membrane unit 10 enables the MEMS speaker array 100 to cover the frequency band of 2 kHz to 20 kHz. Therefore, the MEMS speaker array 100 can set the number of diaphragm units 10 with different resonant frequencies according to the requirements of the specific frequency band, which is not specifically limited here.
  • the MEMS speaker array 100 includes six diaphragm units 10 with different resonant frequencies.
  • a damping structure can be provided on at least one diaphragm unit 10.
  • the damping structure is On the one hand, it can reduce the resonance peak of the diaphragm unit 10 at the resonance, thereby suppressing the sound pressure level peak; on the other hand, it weakens the acoustic coupling between different diaphragm units 10, and at the same time, the vibration phase difference between different diaphragm units 10 is reduced. Small, thereby raising the sound pressure level valleys between different resonances, thereby enabling the MEMS speaker array 100 to obtain flat and smooth high-output sound pressure frequency response characteristics.
  • this method solves the sound cancellation problem caused by phase reversal in the mechanical/acoustic part of the MEMS speaker array 100, it simplifies the complexity of the circuit part that controls the MEMS speaker array 100: the circuit that controls the MEMS speaker array 100 does not require For inputting different electrical signal amplitudes and phases to the diaphragm unit 10 with different resonant frequencies (for example, the circuit part does not require a frequency divider to input high-frequency electrical signals and low-frequency electrical signals to the high-frequency unit and low-frequency unit respectively, and no circuit is required. The part inputs electrical signals of different phases to the high-frequency unit and the low-frequency unit respectively).
  • This method has a simple structure, low cost, and high integration.
  • the number of input signal ports of the control circuit to the MEMS speaker array 100 is much smaller than the number of diaphragm units 10 with different resonant frequencies. For example, only one input signal is needed to control all vibrations.
  • the number of input signal ports corresponding to the membrane unit 10, that is, the MEMS speaker array, is 1.
  • FIG. 1E six diaphragm units 10 are driven through one input signal channel (the input signal channel is represented by St in the figure); and as shown in Figure 1F, through two signal channels (two signal channels Indicated by St1 and St2 respectively in the figure), six diaphragm units 10 are driven.
  • the acoustic coupling between each diaphragm unit 10 can be weakened, The resonance peaks of the multiple diaphragm units 10 are smoothly transitioned.
  • the spacing between the resonant frequencies between adjacent diaphragm units 10 may, for example, satisfy the following conditions:
  • the resonant frequencies of each diaphragm unit 10 in the diaphragm unit array increase sequentially, and among the diaphragm units 10 arranged in order according to the resonant frequency, the vibration phase difference of two adjacent diaphragm units 10 is less than 180° degree, that is, in the frequency range between when the previous diaphragm unit 10 reaches the resonant frequency and when the next diaphragm unit 10 reaches the resonant frequency, the vibration phase difference between the two is within 180 degrees.
  • the vibration phase difference of the diaphragm unit 10 is less than 120 degrees, that is, in the frequency range between when the previous diaphragm unit 10 reaches the resonant frequency and when the next diaphragm unit 10 reaches the resonant frequency, the vibration phase difference between the two is within 120 degrees.
  • the vibration phase difference of two adjacent diaphragm units 10 is less than 90 degrees, that is, from the time the previous diaphragm unit 10 reaches the resonant frequency to the next diaphragm
  • the unit 10 reaches the frequency band between the resonant frequencies, and the vibration phase difference between the two is within 90 degrees.
  • multiple diaphragm units 10 can alternately become the main sound-emitting units of the MEMS speaker array 100 as the resonant frequency changes, thereby making the MEMS speaker array 100 covers a resonance state with high energy conversion efficiency in a wide frequency band. While improving the sound generation efficiency, it can weaken the acoustic coupling between each diaphragm unit 10, so that the MEMS speaker array 100 can obtain a flat and smooth high output sound pressure frequency. Response characteristics.
  • Figure 1G is a simulation rendering of the frequency response of the phase difference to the sound pressure level in the MEMS speaker array provided by the embodiment of the present application. It can be seen from FIG. 1G that the smaller the vibration phase difference between two adjacent diaphragm units 10, the smoother the transition between resonance peaks and the flatter the response. After adding damping, the vibration phase difference of the diaphragm unit 10 is reduced, which raises the sound pressure level valley between different resonances.
  • the vibration phase difference of different diaphragm units 10 is greater than 120 degrees before adding damping elements, but is less than 120 degrees after adding damping elements; or the vibration phase difference of different diaphragm units 10 is greater than 90 degrees before adding damping elements, and adding damping elements Then less than 90 degrees.
  • the damping structure may be at least one of an acoustic damping member and a mechanical damping member 80 . It can be understood that by providing the acoustic damping member or the mechanical damping member 80 , acoustic damping or mechanical damping may be applied to the MEMS speaker array 100 . Mechanical damping is used to block or weaken the acoustic coupling between the diaphragm units 10.
  • the base 23 is provided with a sound hole 110, and the diaphragm unit 10 is correspondingly disposed in the sound hole 110.
  • the shape of the sound hole 110 can match the shape of the diaphragm unit 10 , and when the diaphragm unit 10 is disposed in the sound hole 110 , at least one side wall of the diaphragm unit 10 is in contact with the sound hole 110 A gap is provided between the hole walls, so that the diaphragm unit 10 can have a corresponding vibration space in the sound hole 110, thereby achieving the purpose of vibrating and producing sound.
  • the cross-sectional shape of each diaphragm unit 10 is rectangular, and the cross-sectional shape of the sound hole 110 is correspondingly rectangle.
  • one diaphragm unit 10 is arranged opposite to one sound hole 110; alternatively, multiple diaphragm units 10 may be arranged opposite to one sound hole 110. Specifically, adaptive design is performed according to actual needs, for example, in In FIG. 1A , one diaphragm unit 10 corresponds to one sound hole 110 .
  • the MEMS speaker array 100 includes an acoustic damping member disposed opposite to the sound hole 110 .
  • the acoustic damping member may be located within the sound hole 110 ; or, the acoustic damping member may be disposed on a side of the sound hole 110 away from the diaphragm unit 10 and cover at least part of the diaphragm unit 10 .
  • At least one diaphragm unit 10 must first have a front cavity 300 or a back cavity 30 that is independent of other units, and at the same time, on the side of its front cavity 300 or back cavity 30 Cover acoustic damping pieces to block acoustic coupling paths.
  • the diaphragm unit 10 and the hole walls of the sound hole 110 together form a back cavity 30, as shown in FIGS. 1B and 1C.
  • the MEMS speaker array 100 further includes an upper cover 90 , which may be made of semiconductor materials such as silicon; the upper cover 90 is connected to the base 23 , and is disposed away from the back cavity 30 of the diaphragm unit 10 on one side, and the upper cover 90 and the diaphragm unit 10 form at least one front cavity 300 .
  • an upper cover 90 which may be made of semiconductor materials such as silicon; the upper cover 90 is connected to the base 23 , and is disposed away from the back cavity 30 of the diaphragm unit 10 on one side, and the upper cover 90 and the diaphragm unit 10 form at least one front cavity 300 .
  • the acoustic damping member can cover the back cavity 30 area (as shown in 1B and 1C) or the front cavity 300 area (as shown in Figures 10A and 10B) corresponding to all diaphragm units 10; it can also cover part of the diaphragm unit. 10 corresponds to the back cavity 30 area (as shown in FIG. 1D) or the front cavity 300 area.
  • the acoustic damping component includes a damping net 50
  • the damping net 50 can be connected to the side of the base 23 away from the vibration unit through bonding or other means.
  • the damping net 50 and the base 23 face away from each other.
  • An adhesive layer 40 is provided between one side of the diaphragm unit 10 , wherein the adhesive layer 40 can be arranged near the edge around the damping net 50 to fix the damping net 50 to the base through the adhesive layer 40 23 away from the diaphragm unit 10 , thereby weakening the acoustic coupling between the diaphragm units 10 .
  • the six diaphragm units 10 have different shapes and sizes, and the MEMS speaker array 100 will generate six different resonant frequencies.
  • the resonance of each diaphragm unit 10 The frequency is optimized and designed according to actual needs, so that in the frequency range between when the previous diaphragm unit 10 reaches the resonance state and when the next diaphragm unit 10 reaches the resonance state, the vibration phase difference between the two can be within 120 degrees, for example. To ensure that the sound cancellation is at a small level, thereby ensuring the smoothness of the frequency response curve.
  • Figure 2A is a schematic diagram of the simulation effect of a structure of a multi-resonance speaker provided by an embodiment of the present application
  • Figure 2B is a comparison chart of the frequency response curves of the multi-resonance structure speaker shown in this embodiment and a single resonant frequency speaker of the same area
  • FIG. 2C is a schematic diagram of experimental results when the resonant frequency is 2 in the MEMS speaker array provided by the embodiment of the present application.
  • f1 ⁇ f15 in Figure 2A represent 15 different resonant frequencies; it can be seen from Figure 2A that the MEMS speaker array 100 with multiple resonant frequencies can achieve higher bandwidth and sensitivity at the same time; from Figure 2B and Figure 2C It can be clearly seen that the MEMS speaker array 100 with multiple resonant frequencies has a flatter response and wider bandwidth than the MEMS speaker array 100 with a single resonant frequency without damping (such as the damping network 50). At the same time, with the applied Compared with the damped single resonant frequency MEMS speaker, the MEMS speaker array 100 with multiple resonant frequencies has higher sensitivity and better response amplitude.
  • the MEMS speaker array 100 with multiple resonant frequencies only needs to add small damping to achieve an extremely flat response; while for the MEMS speaker array 100 with a single resonant frequency of the same area, a larger damping needs to be added.
  • the damping can achieve a comparable flatness, resulting in its lower sensitivity; therefore, the MEMS speaker array 100 with multiple resonant frequencies can achieve higher bandwidth and sensitivity at the same time, while the MEMS speaker array 100 with a single resonant frequency and The damped single resonant frequency MEMS speaker array 100 can only satisfy one of bandwidth and sensitivity.
  • Figure 3C is a schematic diagram comparing the frequency response curves of the multi-resonant frequency MEMS speaker array with independent back cavity and acoustic damping provided by the embodiment of the present application and the structure of Figures 3A and 3B;
  • Figure 3D is the MEMS speaker array provided by the embodiment of the present application. Schematic diagram of another experimental result when the medium resonant frequency is 2.
  • no damping structure may be provided on the diaphragm unit 10 , as shown in FIG. 3A ; or, a damping structure may be provided on each diaphragm unit 10 , but the back cavities 30 are connected to each other, that is, each back cavity 30 is interconnected.
  • the diaphragm unit 10 does not have an independent back cavity 30, as shown in Figure 3B; by simulating and comparing the structures of Figures 1B, 3A and 3B, the comparison results are shown in Figures 3C and 3D.
  • the MEMS speaker array 100 has a flatter response than the multi-resonant frequency MEMS speaker array 100 without added acoustic damping and the multi-resonant frequency MEMS speaker array 100 with added acoustic damping but no independent cavity/back cavity.
  • the multi-resonant frequency MEMS speaker array 100 with added damping but without independent front/rear cavities will experience very low sound pressure level valleys.
  • the acoustic damping member can also be a damping plate 60 .
  • the damping plate 60 is provided with a plurality of through holes 61 , and the plurality of through holes 61 are arranged opposite to the diaphragm unit 10 .
  • the through hole 61 on the damping plate 60 has a damping function to weaken the acoustic coupling of the diaphragm unit 10 through the through hole 61 .
  • the size and distribution of the through holes 61 on the damping plate 60 can be adaptively designed and adjusted according to the actual situation.
  • the material of the damping plate 60 can be a semiconductor material such as silicon, and can be etched through a process such as etching small holes. Formed, when the material of the damping plate 60 is a semiconductor material such as silicon, the damping plate 60 can be connected to the base 23 of the MEMS speaker array 100 through bonding. For example, in FIG. 5 , the damping plate 60 and the base 23 are connected.
  • a bonding layer 70 is disposed between the damping plates 60 and the substrate 23 to realize a bonding connection between the damping plate 60 and the substrate 23 through the bonding layer 70 .
  • the plurality of through holes 61 may be evenly distributed on the damping plate 60 , and the aperture size of each through hole 61 is equal, as shown in FIG. 4A .
  • the plurality of through holes 61 form at least two through hole arrays 611 , and different through hole arrays 611 are respectively arranged corresponding to the diaphragm unit 10 , that is, one through hole array 611 corresponds to at least one diaphragm unit 10 .
  • the at least two via arrays 611 include a first via array 611 and a second via array 611 , the first via array 611 and the second via array 611 having different numbers of vias 61 and/or Or the size of the through holes 61 so that the diaphragm units 10 corresponding to the first through hole array 611 and the second through hole array 611 have different acoustic damping.
  • At least two via arrays 611 include a first via array 611 , a second via array 611 , a third via array 611 , a fourth via array 611 , and a fifth via array 611 .
  • Hole array 611 and sixth through-hole array 611 wherein the through-holes 61 of each through-hole array 611 have different sizes, and the number of through-holes 61 of each through-hole array 611 is also different. In this way, different through-hole arrays 611 have different acoustic properties. Damping to weaken the acoustic coupling with its corresponding diaphragm unit 10.
  • the damping structure is a mechanical damping component 80.
  • the mechanical damping component 80 includes a mechanical damping layer covering at least part of the diaphragm unit 10.
  • the mechanical damping layer covers at least one diaphragm unit. Yuan 10.
  • a mechanical damping layer is provided on the diaphragm unit 10 , and the mechanical damping layer covers the entire diaphragm unit 10 ; of course, the mechanical damping layer can also cover only part of the diaphragm unit 10 , as shown in FIG. 8
  • the acoustic coupling of the diaphragm unit 10 can be weakened.
  • the material of the mechanical damping layer may be a high-loss material, for example, the polymer material Parylene (PI).
  • PI Parylene
  • a damping net 50 is also provided on a side of the diaphragm unit 10 away from the mechanical damping layer, wherein the damping net 50 can cover at least one diaphragm unit.
  • the mechanical damping layer can also cover at least one diaphragm unit 10. For example, in Figure 7, one side of the diaphragm unit 10 is covered with a mechanical damping layer, and the side of the diaphragm unit 10 facing away from the mechanical damping layer A damping net 50 covering the entire diaphragm unit 10 is provided.
  • the acoustic coupling of the diaphragm unit 10 can be further weakened, thereby enabling the MEMS speaker array 100 to obtain flatter and smoother high-output sound pressure frequency response characteristics.
  • the diaphragm unit 10 and the sound hole 110 together form at least two back cavities 30 , and the at least two back cavities 30 include a first back cavity.
  • the diaphragm units 10 in the diaphragm unit array corresponds to some of the diaphragm units 10 in the diaphragm unit array.
  • the first back cavity may correspond to one diaphragm unit 10 unit, or may correspond to two or more diaphragm units 10.
  • the first back cavity corresponds to two diaphragm units 10.
  • each back cavity 30 corresponds to a different diaphragm unit 10 respectively.
  • one back cavity 30 corresponds to one diaphragm unit 10 .
  • At least two back cavities 30 further include second back cavities, and the second back cavities correspond to at least two diaphragm units 10 , that is to say, the second back cavities correspond to two or more diaphragms.
  • the first back cavity can correspond to one diaphragm unit 10 or two or more diaphragm units 10.
  • the number of back chambers 30 is one, and the number of front chambers 300 is one, two, or more than two.
  • the number of back cavities 30 is at least two; and/or the number of front cavities 300 is The quantity is at least two.
  • each front cavity 300 is independent of each other and corresponds to different diaphragm units 10 .
  • the damping net 50 covers each front cavity corresponding to each diaphragm unit 10 . 300 area.
  • the number of back cavities 30 is at least two, and the number of front cavities 300 is also at least two.
  • one diaphragm unit 10 is provided corresponding to one back cavity 30 and one front cavity 300 respectively; or, At least two diaphragm units 10 correspond to a common back cavity 30 , and each diaphragm unit 10 independently corresponds to a front cavity; or, at least two diaphragm units 10 correspond to a common front cavity 300 , and each diaphragm unit 10 corresponds to a common front cavity 300 , and each diaphragm unit 10 corresponds to a common front cavity 300 .
  • the units 10 each independently correspond to a back cavity 30 and so on.
  • the number of the back cavities 30 , the number of the front cavities 300 and the number of the diaphragm units 10 can be arbitrarily combined, and there is no limit here.
  • the upper cover 90 is provided with a hollow structure, and the hollow structure is provided corresponding to the diaphragm unit 10 to reduce the acoustic coupling between the diaphragm units 10 through the hollow structure.
  • the first diaphragm unit 10 and the second diaphragm unit 10 respectively have different shapes; and/or the first diaphragm unit 10 and the second diaphragm unit 10 respectively have different diaphragm coverage areas. . That is to say, each diaphragm unit 10 in the diaphragm unit array may have a different shape, so as to achieve different resonant frequencies of the diaphragm unit 10 by changing the shape of the diaphragm unit 10; or the diaphragm unit 10 may have different shapes.
  • the size is different, that is, the coverage area of each diaphragm unit 10 can be different in size to achieve different resonant frequencies through the size of the diaphragm unit 10; or, the shape and size of each diaphragm unit 10 are different to achieve different resonant frequencies through the cover plate.
  • the differences in shape and size of the diaphragm unit 10 jointly achieve changes in the resonant frequency.
  • the type of the diaphragm unit 10 may include at least one of a cantilever beam diaphragm unit 10 and a fixed circular diaphragm unit 10 .
  • each diaphragm unit 10 evenly use four identical triangular cantilever beams as the planar structure of one diaphragm unit 10 , and each diaphragm unit 10 has the same shape.
  • each diaphragm The size of the area covered by the average structure of unit 10 varies so that The resonant frequencies of the two diaphragm units 10 are different.
  • FIG. 11B four identical triangular cantilever beams are also used as the planar structure of a diaphragm unit 10 .
  • the diaphragm unit array has nine diaphragm units 10 , and four of the diaphragm units are The coverage areas of the four diaphragm units 10 are equal in size. Therefore, the resonant frequencies of the four diaphragm units 10 are equal, while the resonant frequencies of the other five diaphragm units 10 are different in size.
  • the three diaphragm units 10 added in 11B can be represented by the seventh diaphragm unit 10 , the eighth diaphragm unit 10 , and the ninth diaphragm unit 10 respectively.
  • each diaphragm unit 10 is a fixed circular diaphragm, and the coverage area of the planar structure of each diaphragm unit 10 is not equal, because each fixed circular diaphragm is a fully enclosed structure.
  • the front cavity 300 and the back cavity 30 of the diaphragm unit 10 are isolated, so that a smoother low-frequency response can be obtained.
  • the diaphragm unit array integrates diaphragm units 10 of different shapes on a planar structure such as a fixed circular diaphragm, a triangular cantilever beam, a straight trapezoidal cantilever beam, an inverted trapezoidal cantilever beam, etc.
  • a planar structure such as a fixed circular diaphragm, a triangular cantilever beam, a straight trapezoidal cantilever beam, an inverted trapezoidal cantilever beam, etc.
  • Different resonant frequencies are achieved by changing the shape of the diaphragm unit 10 on the planar structure.
  • the structure in the thickness direction can also be changed to achieve different resonant frequencies; for example, as shown in Figures 14A and 14B, by A part of each diaphragm unit 10 is etched and removed to change the equivalent mass and equivalent stiffness of the diaphragm unit 10, thereby changing the resonant frequency.
  • each diaphragm unit 10 can have different equivalent masses and equivalent stiffnesses, so that each diaphragm unit 10 has a different equivalent mass and equivalent stiffness. 10 have different resonant frequencies.
  • the number of diaphragm units 10 in the diaphragm unit array can be set as needed, and there is no specific limit on the number.
  • the diaphragm units 10 are equal to each other, so that the 24 diaphragm units 10 all have different diaphragm frequencies.
  • the MEMS speaker array 100 further includes a driver 400 configured to drive the diaphragm unit 10 to couple vibrations.
  • the driver 400 is disposed around the circumferential outside of the diaphragm unit 10, and the driver 400 couples vibration with the diaphragm unit 10 through the coupling structure 500, as shown in FIG. 16A.
  • the electrodes of the driver 400 may fully cover or partially cover the circumferential outside of the vibration unit.
  • the first diaphragm unit 10 and the second diaphragm unit 10 respectively have different shapes, so that each diaphragm unit 10 has different resonant frequencies through different shapes, as shown in FIG. 16B .
  • the first diaphragm unit 10 and the second diaphragm unit 10 respectively have different diaphragm coverage areas.
  • the diaphragm unit 10 includes three diaphragm units 10 , and the three diaphragm units 10 have different diaphragm coverage areas, that is, the three diaphragm units 10 have different planar dimensions, so that each of the three diaphragm units 10 has different diaphragm coverage areas.
  • the diaphragm unit 10 has different resonant frequencies.
  • the first diaphragm unit 10 and the second diaphragm unit 10 respectively correspond to different free boundary lengths of the driver 400 to achieve different resonant frequencies, as shown in FIG. 16D .
  • the MEMS speaker array 100 also includes a mass block 600.
  • the driver 400 drives the diaphragm unit 10 to couple vibration through the mass block 600.
  • the mass blocks 600 corresponding to different diaphragm units 10 have different masses, as shown in Figure 17A and Figure 17A. As shown in 17B, it can be understood that each diaphragm unit 10 can have different resonant frequencies through mass blocks 600 of different masses.
  • each diaphragm unit 10 in the planar structure may be the same or different; for example, in FIG. 17C , the shape and size of each diaphragm unit 10 in the planar structure are the same.
  • the mass blocks 600 corresponding to each diaphragm unit 10 are different to achieve different resonant frequencies of each diaphragm unit 10 .
  • a damping structure can be provided on the diaphragm unit 10 to achieve different resonant frequencies. That is to say, the above-mentioned ways of changing the resonant frequency can be freely combined. Here , without specific restrictions.
  • each diaphragm unit 10 in the diaphragm unit array is spaced and arranged side by side in the same direction, and an air cavity is formed between each adjacent diaphragm unit 10.
  • Different diaphragm units 10 have different sizes.
  • an air cavity is formed between adjacent diaphragm units 10 .
  • L1 to L9 are the widths of the air cavities
  • L0 is the distance from the end of the diaphragm unit 10 to the base 23 .
  • Distance in this embodiment, can be achieved by changing the size of the diaphragm unit 10 to achieve different resonant frequencies, and the width of each air cavity can be the same or different.
  • L0 is less than 30 ⁇ m
  • the two air cavities can be approximately independent of each other.
  • the MEMS speaker array 100 also includes a lower cover, which is disposed on the side of the diaphragm unit 10 away from the upper cover 90 and covers all or part of the diaphragm unit 10; in some embodiments, the lower cover acts as a damping plate 60 , its material can be silicon material.
  • the lower cover is used as the damping plate 60 as an example for description.
  • Figure 18C shows the structure of the damping plate 60 (lower cover) and the upper cover 90.
  • figure a in Figure 18C is a schematic diagram of the damping plate 60
  • figure b in Figure 18C is a schematic diagram of the upper cover 90
  • the damping plate 60 and the upper cover The cover 90 can be connected to the corresponding structure in FIG. 18A to form an independent cavity.
  • h in the figure represents an air hole, and the air hole can have a damping effect to weaken the acoustic coupling between the diaphragm units 10 .
  • the structures of the damping plate 60 and the upper cover 90 may be the same. As shown in FIG. 18D , multiple small holes of the same shape and size may be etched on the damping plate 60 and the upper cover 90 . Damping is achieved through small holes, thereby weakening the acoustic coupling between the diaphragm units 10 .
  • the plurality of small holes can form a plurality of different small hole arrays, and each small hole array is respectively arranged corresponding to the diaphragm unit 10 .
  • the extension dimensions of the diaphragm unit 10 in the length direction of the diaphragm unit 10 are different, wherein the length direction of the diaphragm unit 10 and the arrangement direction of the diaphragm unit 10 are perpendicular to each other.
  • each diaphragm unit 10 has different resonant frequencies.
  • FIGS. 19A and 19B different resonant frequencies can be achieved by changing the length of the diaphragm unit 10 .
  • the shape and structure of the damping plate 60 and the upper cover 90 can be the same, and the damping plate 60 and the upper cover 90 can have the same shape and structure.
  • a damping hole is formed on the upper cover, and the structural shape of the damping hole can match the shape and size of the diaphragm unit 10.
  • Figure a in Figure 19A is a schematic structural diagram of the damping plate 60 and the upper cover 90;
  • Figure b in Figure 19A is a schematic diagram of the vibration film unit 10.
  • the damping holes formed on the damping plate 60 and the upper cover 90 can be at least two damping hole arrays, correspondingly, as shown in Figure 19B (b)
  • multiple diaphragm units 10 can also form corresponding diaphragm arrays, wherein the diaphragm array includes at least two diaphragm units 10; so that one diaphragm array corresponds to one damping hole array, and different damping hole arrays
  • the shape and size can be different.
  • the cross-sectional structures in the thickness direction of the diaphragm unit 10 of all MEMS speaker arrays 100 include a stacked structural layer 1, a piezoelectric layer 2, and an electrical layer.
  • Electrode layer 3 wherein the electrode layer 3 includes a top electrode and a bottom electrode, and the materials of the top electrode and the bottom electrode can be molybdenum, platinum, gold and other conductive metals; the piezoelectric layer 2 can be AlN and its rare earth doped structure; structure
  • the material of layer 1 may be, for example, silicon, AlN and other materials.
  • the piezoelectric layer 2 includes a first electrode 21 and a second electrode 22 , and there are two first electrodes 21 , and the two electrodes are located outside the electrode layer 3 respectively; there are also two second electrodes 22 , and both electrodes are located outside the electrode layer 3 .
  • the second electrode layers 22 are respectively located on opposite sides of the structural layer 1; when the material of the structural layer 1 is a conductive material, the electrodes on the side close to the structural layer 1 can be omitted.
  • MEMS speaker array 100 made of piezoelectric material diaphragms
  • other types of MEMS speaker arrays 100 may also be used, such as the electrostatic MEMS speaker array 100 made of electrode material diaphragms, or the electromagnetic MEMS speaker array 100 made of electromagnetic material diaphragms. MEMS speaker array 100.
  • the MEMS speaker array provided by the embodiment of the present application includes a substrate and a diaphragm unit array arranged on the substrate.
  • a sound hole is provided on the substrate.
  • the diaphragm unit array includes at least two diaphragm units arranged at intervals.
  • the diaphragm units are correspondingly arranged on Within the sound hole, at least two diaphragm units have at least two different resonant frequencies.
  • multiple different resonant frequencies can cover a relatively wide operating bandwidth, thereby satisfying the operating bandwidth of the MEMS speaker array. Improve the sound efficiency of MEMS speaker arrays.

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Abstract

一种MEMS扬声器阵列（100），涉及MEMS扬声器领域，用于解决MEMS扬声器的发声效率和工作带宽无法同时满足的技术问题。MEMS扬声器阵列（100）包括基底（23）和设置在基底（23）上的振膜单元阵列，振膜单元阵列包括至少两个间隔设置的振膜单元（10），且至少两个振膜单元（10）具有至少两个不同的谐振频率，能够满足MEMS扬声器阵列（100）的工作带宽的同时，提高MEMS扬声器阵列（100）的发声效率。

Description

MEMS扬声器阵列
本申请要求于2022年09月08日提交中国专利局、申请号为202211097030.X、申请名称为“MEMS扬声器阵列”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MEMS扬声器领域，尤其涉及一种MEMS扬声器阵列。
背景技术
MEMS(Micro-Electro-Mechanical System)扬声器，即微机电系统扬声器，其相对传统扬声器具有高线性度、易于大批量制造、与CMOS兼容等优势。然而，相关技术中，在提高MEMS扬声器的发声效率的同时，存在无法满足MEMS扬声器的工作带宽的技术问题。
发明内容
鉴于上述问题，本申请实施例提供一种MEMS扬声器阵列，能够提高MEMS扬声器阵列的发声效率的同时，保证MEMS扬声器阵列具有足够宽的工作带宽。
为了实现上述目的，本申请实施例提供如下技术方案：
本申请实施例提供一种MEMS扬声器阵列，包括基底和设置在所述基底上的振膜单元阵列，所述基底上设置有声孔，所述振膜单元阵列包括至少两个间隔设置的振膜单元，所述振膜单元对应设置于所述声孔内，且至少两个振膜单元具有至少两个不同的谐振频率。
作为一种可选的实施方式，所述至少两个振膜单元包括至少一个第一振膜单元和至少一个第二振膜单元，所述第一振膜单元和所述第二振膜单元分别具有不同的谐振频率。
作为一种可选的实施方式，所述振膜单元上设置有声学阻尼件和机械阻尼件中的至少一者。
作为一种可选的实施方式，所述基底上设置有声孔，所述振膜单元对应设置于所述声孔内。
作为一种可选的实施方式，所述MEMS扬声器阵列包括所述声学阻尼件，所述声学阻尼件与所述声孔相对设置。
作为一种可选的实施方式，所述MEME扬声器阵列包括所述声学阻尼件，所述声学阻尼件设置于所述声孔的背离所述振膜单元的一侧。
作为一种可选的实施方式，声学阻尼件覆盖至少部分所述振膜单元。
作为一种可选的实施方式，所述声学阻尼件覆盖所有所述振膜单元的表面。
作为一种可选的实施方式，所述声学阻尼件包括阻尼网。
作为一种可选的实施方式，所述声学阻尼件为阻尼板，所述阻尼板上设置有多个通孔，多个所述通孔和所述振膜单元相对设置。
作为一种可选的实施方式，所述阻尼板为硅板。
作为一种可选的实施方式，多个所述通孔形成至少两个通孔阵列，不同的所述通孔阵列分别和所述振膜单元对应设置。
作为一种可选的实施方式，至少两个所述通孔阵列包括第一通孔阵列和第二通孔阵列，所述第一通孔阵列和所述第二通孔阵列具有不同的通孔数量和/或通孔大小，以使所述第一通孔阵列和所述第二通孔阵列对应的振膜单元具有不同的声学阻尼。
作为一种可选的实施方式，所述机械阻尼件包括覆盖至少部分所述振膜单元的机械阻尼层，所述机械阻尼层覆盖至少一个所述振膜单元。
作为一种可选的实施方式，所述振膜单元和所述声孔的孔壁共同围成背腔。
作为一种可选的实施方式，所述振膜单元和所述声孔共同围成至少两个背腔，所述至少两个背腔包括第一背腔，所述第一背腔对应于所述振膜单元阵列中的部分所述振膜单元。
作为一种可选的实施方式，所述第一背腔对应于所述振膜单元阵列中的单个所述振膜单元。
作为一种可选的实施方式，各所述背腔分别对应于不同所述振膜单元。
作为一种可选的实施方式，所述至少两个背腔还包括第二背腔，所述第 二背腔对应至少两个所述振膜单元。
作为一种可选的实施方式，还包括上盖，所述上盖连接于所述基底，所述上盖设置于所述振膜单元的背离所述背腔的一侧，且所述上盖和所述振膜单元围成至少一个前腔。
作为一种可选的实施方式，所述背腔的数量为至少两个；和/或，所述前腔的数量为至少两个。
作为一种可选的实施方式，所述前腔为至少两个，且各所述前腔分别对应不同所述振膜单元。
作为一种可选的实施方式，所述第一振膜单元和所述第二振膜单元分别具有不同的形状；和/或，所述第一振膜单元和所述第二振膜单元分别具有不同的振膜覆盖面积。
作为一种可选的实施方式，所述振膜单元的类型包括悬臂梁式振膜单元和固支圆膜振膜单元中的至少一种。
作为一种可选的实施方式，还包括驱动器，所述驱动器被配置为带动所述振膜单元耦合振动。
作为一种可选的实施方式，所述驱动器围设于所述振膜单元周向外侧，且所述驱动器通过耦合结构和所述振膜单元耦合振动。
作为一种可选的实施方式，所述第一振膜单元和所述第二振膜单元分别具有不同的振膜覆盖面积；和/或，所述第一振膜单元和所述第二振膜单元分别对应不同的驱动器自由边界长度；和/或，所述第一振膜单元和所述第二振膜单元分别具有不同的形状。
作为一种可选的实施方式，还包括质量块，所述驱动器通过所述质量块带动所述振膜单元耦合振动，不同振膜单元对应的所述质量块具有不同的质量。
作为一种可选的实施方式，所述振膜单元阵列中的各所述振膜单元沿同一方向间隔并排排列，且每相邻所述振膜单元之间形成空气腔，不同所述振膜单元具有不同的大小。
作为一种可选的实施方式，不同所述振膜单元在排列方向上具有不同厚度；和/或，不同所述振膜单元在所述振膜单元的长度方向上的延伸尺寸不同，其中，所述振膜单元的长度方向和所述振膜单元的排列方向相互垂直。
作为一种可选的实施方式，所述振膜单元阵列中的各所述振膜单元的谐振频率依次递增，且依照谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于180度。
作为一种可选的实施方式，根据谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于120度。
作为一种可选的实施方式，根据谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于90度。
作为一种可选的实施方式，所述MEMS扬声器阵列对应的输入信号端口数小于所述振膜单元的数量。
作为一种可选的实施方式，所述MEMS扬声器阵列对应的输入信号端口数为1。
作为一种可选的实施方式，不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之前大于120度；不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之后小于120度。
作为一种可选的实施方式，不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之前大于90度；不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之后小于90度。
本申请实施例提供的MEMS扬声器阵列，包括基底和设置在基底上的振膜单元阵列，振膜单元阵列包括至少两个间隔设置的振膜单元，且至少两个振膜单元具有至少两个不同的谐振频率。上述方案中，通过使至少两个振膜单元具有至少两个不同的谐振频率，这样，多个不同的谐振频率可以覆盖比较宽的工作带宽，从而在能够满足MEMS扬声器阵列的工作带宽的同时，提高MEMS扬声器阵列的发声效率。
除了上面所描述的本申请实施例解决的技术问题、构成技术方案的技术特征以及由这些技术方案的技术特征所带来的有益效果外，本申请实施例提供的MEMS扬声器阵列所能解决的其他技术问题、技术方案中包含的其他技术特征以及这些技术特征带来的有益效果，将在具体实施方式中作出进一步详细的说明。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作一简单地介绍，显而易见地，下面描述中的附图是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1A为本申请实施例提供的MEMS扬声器阵列的俯视示意图；
图1B为图1A中A-A处的剖面示意图；
图1C为本申请实施例提供的MEMS扬声器阵列的仰视示意图；
图1D为本申请实施例中阻尼网50覆盖部分振膜单元的示意图；
图1E为本申请实施例提供的MEMS扬声器阵列的一种驱动方式示意图；
图1F为本申请实施例提供的MEMS扬声器阵列的另一种驱动方式示意图；
图1G为本申请实施例提供的MEMS扬声器阵列中相位差对声压级频率响应的仿真效果图；
图2A为本申请实施例提供的多谐振扬声器的一种结构的原理示意图；
图2B为本申请实施例提供的MEMS扬声器阵列与单一谐振频率扬声器的频率响应曲线对比示意图；
图2C为本申请实施例提供的MEMS扬声器阵列中谐振频率为2时的一种实验结果示意图；
图3A为图1A中A-A处的剖面结构且未施加阻尼结构的剖面示意图；
图3B为图1A中A-A处的剖面结构并施加阻尼结构但没有独立背腔的剖面示意图；
图3C为本申请实施例提供的具有独立背腔并施加声学阻尼的多谐振频率MEMS扬声器阵列与图3A和图3B结构的频率响应曲线对比示意图；
图3D为本申请实施例提供的MEMS扬声器阵列中谐振频率为2时的另一种实验结果示意图；
图4A为本申请实施例中阻尼板的一种结构示意图；
图4B为本申请实施例中阻尼板的另一种结构示意图；
图5为本申请实施例提供的MEMS扬声器阵列的一种结构的剖面示意图；
图6为本申请实施例中阻尼结构为机械阻尼件的一种结构示意图；
图7为在图6的基础上施加阻尼网的结构示意图；
图8为本申请实施例中机械阻尼件覆盖部分振膜单元的结构示意图；
图9为本申请实施例中具有至少两个背腔的一种结构示意图；
图10A为本申请实施例中具有前腔的一种结构示意图；
图10B为本申请实施例中具有前腔的另一种结构示意图；
图11A为本申请实施例提供的振膜单元阵列的第一种结构示意图；
图11B为本申请实施例提供的振膜单元阵列的第二种结构示意图；
图12为本申请实施例提供的振膜单元阵列的第三种结构示意图；
图13为本申请实施例提供的振膜单元阵列的第四种结构示意图；
图14A为本申请实施例提供的振膜单元阵列的第五结构示意图；
图14B为图14A中B-B处的剖面示意图；
图15为本申请实施例提供的振膜单元阵列的第六结构示意图；
图16A为本申请实施例提供的振膜单元阵列的第七结构示意图；
图16B为本申请实施例提供的振膜单元阵列的第八结构示意图；
图16C为本申请实施例提供的振膜单元阵列的第九结构示意图；
图16D为本申请实施例提供的振膜单元阵列的第十结构示意图；
图17A为本申请实施例提供的振膜单元阵列的第十一结构示意图；
图17B为图17A处D-D处的剖面结构示意图；
图17C为本申请实施例提供的振膜单元阵列的第十二结构示意图；
图18A为本申请实施例提供的振膜单元阵列的第十三结构示意图；
图18B为图18A处的E处的局部放大示意图；
图18C为本申请实施例提供的阻尼板和上盖的一种结构示意图；
图18D为本申请实施例提供的阻尼板和上盖的另一种结构示意图；
图19A为本申请实施例提供的阻尼板和上盖的又一种结构示意图；
图19B为本申请实施例提供的阻尼板和上盖的又一种结构示意图；
图20A为本申请实施例提供的振膜单元的一种结构的剖面示意图；
图20B为本申请实施例提供的振膜单元的另一种结构的剖面示意图；
图20C为本申请实施例提供的振膜单元的又一种结构示意图。
附图标记：
100-MEMS扬声器阵列；10-振膜单元；110-声孔；23-基底；
30-背腔；40-粘接层；50-阻尼网；60-阻尼板；61-通孔；
611-通孔阵列；70-键合层；80-机械阻尼件；90-上盖；300-前腔；
400-驱动器；500-耦合结构；600-质量块；1-结构层；2-压电层；
21-第一电极；22-第二电极；3-电极层。
具体实施方式
本申请的发明人在实际工作过程中发现，MEMS振膜阵列在谐振频率附近能达到非常高的能量转化效率，从而能够提升MEMS振膜的发声效率，然而，MEMS振膜阵列中单个振动单元的谐振频率只能覆盖非常窄的带宽，而MEMS扬声器所需要的工作带宽较宽，因此，在提高MEMS扬声器的发声效率的同时，存在无法满足MEMS扬声器的工作带宽的技术问题。
为了解决上述问题，本申请实施例提供一种MEMS扬声器，通过设置多个振膜单元组成阵列，并使多个振膜单元具有不同的谐振频率，这样，多个不同的谐振频率可以使MEMS扬声器阵列覆盖较宽的工作带宽，从而能够在满足MEMS扬声器阵列的工作带宽的同时，提高MEMS扬声器阵列的发声效率。
为了使本申请实施例的上述目的、特征和优点能够更加明显易懂，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅仅是本申请的一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动的前提下所获得的所有其它实施例，均属于本申请保护的范围。
图1A为本申请实施例提供的MEMS扬声器阵列的俯视示意图。请参照图1A所示，本申请实施例提供一种MEMS扬声器阵列100，包括：基底23和设置在基底23上的振膜单元阵列。
可以理解的是，基底23可以为设置在基底23上的振膜单元阵列等器件提供支撑基础。该基底23可以为晶体半导体材料制成，例如，基底23可以为硅(Si)基底，基底23还可以为锗化硅(SiGe)基底、碳化硅(SiC) 基底、绝缘体上硅(silicon-on-insulator，简称SOI)基底等；另外，基底23可以为单层结构，也可以为多层复合结构，具体根据实际需求进行适应性设计，在此不做具体限制，在本申请实施例中，以基底23为硅基底为例进行介绍。
在一些实施例中，振膜单元阵列包括至少两个间隔设置的振膜单元10，且至少两个振膜单元10具有至少两个不同的谐振频率。
上述方案中，振膜单元阵列包括至少两个间隔设置的振膜单元10，并通过使至少两个振膜单元10具有至少两个不同的谐振频率，这样，达到一个振膜单元10的谐振状态之后可以进入下一个振膜单元10的谐振状态，从而使得MEMS扬声器阵列100能够覆盖较宽的工作带宽，且MEMS扬声器阵列100中的振膜单元10在各自的谐振频率附件能够达到较高的能量转化效率，从而能够提高MEMS扬声器阵列100的发声效率。
在一些实施例中，振动单元上具有可驱动的电极和/或功能材料(如压电薄膜、电磁薄膜、电容电极等)，以形成不同类型的MEMS扬声器(压电、电磁、静电等)。
在一些实施例中，至少两个振膜单元10包括至少一个第一振膜单元10和至少一个第二振膜单元10，第一振膜单元10和第二振膜单元10分别具有不同的谐振频率。
示例性的，MEMS扬声器阵列100可以通过设置4～6个不同谐振频率的振膜单元10，使MEMS扬声器阵列100可以覆盖2kHz～10kHz的频段，或者通过设置10～20个具有不同谐振频率的振膜单元10，使MEMS扬声器阵列100可以覆盖2kHz～20kHz的频段，因此，MEMS扬声器阵列100可根据具体频段的需求设置具有不同谐振频率的振膜单元10的数量，在此不做具体限制。
在图1A中，MEMS扬声器阵列100包括六个谐振频率均不相同的振膜单元10。
另外，由于各振动单元的谐振频率不同，当各谐振单元越过谐振频率之后，位移相位会反转，导致产生的声压与阵列中未反相的单元产生异相抵消，声压级频率响应曲线会出现较大的起伏，出现了声压级尖峰和声压级深谷，影响MEMS扬声器阵列100的性能。
为了降低各振膜单元10在谐振处的声压级尖峰，抬升不同谐振频率之间的声压深谷，在本申请实施例中，可以在至少一个振膜单元10上设置阻尼结构，阻尼结构一方面能够降低振膜单元10在谐振处的谐振峰，从而抑制声压级尖峰；另一方面减弱了不同振膜单元10之间的声学耦合，同时不同振膜单元10之间的振动相位差减小，从而抬升不同谐振之间的声压级深谷，进而使MEMS扬声器阵列100能够获得平坦光滑的高输出声压频率响应特性。由于这种方法在MEMS扬声器阵列100的机械/声学部分解决了相位反转带来的声音抵消问题，因此简化了控制MEMS扬声器阵列100的电路部分的复杂度：控制MEMS扬声器阵列100的电路不需要针对不同谐振频率振膜单元10的输入不同的电信号幅值和相位(如电路部分不需要分频器来向高频单元和低频单元分别输入高频电信号和低频电信号，也不需要电路部分向高频单元和低频单元分别输入不同相位的电信号)。这种方法结构简单，成本低，集成度高，控制电路对MEMS扬声器阵列100的输入信号端口数远小于不同谐振频率振膜单元10的个数，例如可以仅需要一路输入信号就可以控制所有振膜单元10，即MEMS扬声器阵列对应的输入信号端口数为1。
示例性的，在图1E中，通过一路输入信号通道(输入信号通道在图中用St表示)驱动六个振膜单元10；而在图1F所示，通过两路信号通道(两路信号通道在图中分别用St1和St2表示)驱动六个振膜单元10。
在一些实施例中，通过在至少一个振膜单元10上设置阻尼结构，并优化相邻振膜单元10之间的谐振频率之间的间隔，可以减弱各振膜单元10之间的声学耦合，使得多个振膜单元10的谐振峰平滑过渡。
其中，相邻振膜单元10之间的谐振频率之间的间隔例如可满足如下条件：
在一个示例中，振膜单元阵列中的各振膜单元10的谐振频率依次递增，且依照谐振频率顺序排列的各振膜单元10中，相邻两个振膜单元10的振动相位差小于180度，即在前一个振膜单元10达到谐振频率之后至后一个振膜单元10达到谐振频率之间的频段内，两者的振动相位差在180度以内。
优选的，根据谐振频率顺序排列的各振膜单元10中，相邻两个振膜单元 10的振动相位差小于120度，即在前一个振膜单元10达到谐振频率之后至后一个振膜单元10达到谐振频率之间的频段内，两者的振动相位差在120度以内。
进一步优选的，根据谐振频率顺序排列的各振膜单元10中，相邻两个振膜单元10的振动相位差小于90度，即在前一个振膜单元10达到谐振频率之后至后一个振膜单元10达到谐振频率之间的频段内，两者的振动相位差在90度以内。
通过使相邻振膜单元10之间的谐振频率的间隔满足如上条件，多个振膜单元10随着谐振频率的改变，可以交替成为MEMS扬声器阵列100的主要发声单元，从而能够使MEMS扬声器阵列100覆盖较宽频段内处于高能量转化效率的谐振状态，提升发声效率的同时，可以减弱各振膜单元10之间的声学耦合，从而使MEMS扬声器阵列100能够获得平坦光滑的高输出声压频率响应特性。
图1G为本申请实施例提供的MEMS扬声器阵列中相位差对声压级频率响应的仿真效果图。由图1G可知，相邻两个振膜单元10的振动相位差越小，谐振峰之间的过渡越平滑，响应越平坦。在加入阻尼后，振膜单元10的振动相位差减小，抬升了不同谐振之间的声压级深谷。例如，不同振膜单元10的振动相位差在加入阻尼件之前大于120度，加入阻尼件之后小于120度；或者不同振膜单元10的振动相位差在加入阻尼件之前大于90度，加入阻尼件之后小于90度。
在一些实施例中，阻尼结构可以是声学阻尼件和机械阻尼件80中的至少一者，可以理解的是，通过设置声学阻尼件或机械阻尼件80，可以向MEMS扬声器阵列100施加声学阻尼或机械阻尼，以阻断或减弱振膜单元10之间的声学耦合。
在一些实施例中，基底23上设置有声孔110，振膜单元10对应设置于声孔110内，
可以理解的是，声孔110的形状可以与振膜单元10的形状相匹配，且振膜单元10设置在声孔110内时，振膜单元10的至少一侧的侧壁与声孔110的孔壁之间设置有间隙，这样，以使得振膜单元10在声孔110内能够具有相应的振动空间，从而实现振动发声的目的。示例性的，在图1A中，各振膜单元10的截面形状为矩形，声孔110的截面形状也相应的为 矩形。
在一些实施例中，一个振膜单元10与一个声孔110相对设置；或者，也可以是多个振膜单元10与一个声孔110相对设置，具体根据实际需求进行适应性设计，例如，在图1A中，一个振膜单元10对应一个声孔110。
在一些实施例中，MEMS扬声器阵列100包括声学阻尼件，声学阻尼件与声孔110相对设置。
在一些实施例中，声学阻尼件可以位于声孔110内；或者，声学阻尼件设置于声孔110的背离振膜单元10的一侧，并覆盖至少部分振膜单元10。
需要说明的是，若向MEMS扬声器阵列100施加声学阻尼，首先要让至少一个振膜单元10拥有独立于其他单元的前腔300或背腔30，同时在其前腔300或背腔30一侧覆盖声学阻尼件，以阻断声学耦合路径。
在一些实施例中，振膜单元10和声孔110的孔壁共同围成背腔30，如图1B和1C中所示。
在一些实施例中，MEMS扬声器阵列100还包括上盖90，上盖90的材料可以为硅等半导体材料；上盖90连接于基底23，上盖90设置于振膜单元10的背离背腔30的一侧，且上盖90和振膜单元10围成至少一个前腔300。
其中，声学阻尼件可以覆盖全部振膜单元10对应的背腔30区域(如1B和1C中所示)或前腔300区域(如图10A和图10B所示)；也可以覆盖部分振膜单元10所对应的背腔30区域(如图1D中所示)或前腔300区域。
在一些实施例中，如图1B所示，声学阻尼件包括阻尼网50，阻尼网50可通过粘接等方式连接于基底23的背离振动单元的一侧，例如，阻尼网50和基底23背离振膜单元10的一侧之间设置有粘接层40，其中，粘接层40可以布置在阻尼网50的四周的靠近边缘处，以通过粘接层40将阻尼网50固定粘接于基底23的背离振膜单元10的一侧，从而减弱振膜单元10之间的声学耦合。
示例性的，在图1A至图1C中，六个振膜单元10的形状大小不同，MEMS扬声器阵列100会产生六个不同的谐振频率，各振膜单元10的谐振 频率根据实际需求进行优化设计，以使得在前一个振膜单元10达到谐振状态之后至后一个振膜单元10达到谐振状态之间的频段内，二者的振动相位差例如可以在120度以内，以保证声抵消在一个较小的水平，从而保证频率响应曲线的平滑性。
图2A为本申请实施例提供的多谐振扬声器的一种结构的仿真效果示意图；图2B为本实施例中所展示的多谐振结构扬声器与相同面积的单一谐振频率扬声器的频率响应曲线对比图；图2C为本申请实施例提供的MEMS扬声器阵列中谐振频率为2时的一种实验结果示意图。其中，图2A中的f1～f15代表15个不同的谐振频率；从图2A中可以看出，具有多谐振频率的MEMS扬声器阵列100可以同时达到较高的带宽和灵敏度；从图2B和图2C中可以明显看出，具有多个谐振频率的MEMS扬声器阵列100拥有比不加阻尼(例如阻尼网50)的单一谐振频率MEMS扬声器阵列100更加平坦的响应和更宽的带宽，同时，与施加了阻尼的单一谐振频率MEMS扬声器相比，具有多谐振频率的MEMS扬声器阵列100的灵敏度更高，响应幅值也更加优异。
另外，需要说明的是，具有多谐振频率的MEMS扬声器阵列100，只需要添加较小的阻尼就可以达到极为平坦的响应；而对于相同面积的单一谐振频率MEMS扬声器阵列100则需要施加更大的阻尼才能达到与之相当的平坦度，从而导致了其较低的灵敏度；因此，具有多谐振频率的MEMS扬声器阵列100可以同时达到较高的带宽和灵敏度，而单一谐振频率的MEMS扬声器阵列100和施加了阻尼的单一谐振频率MEMS扬声器阵列100在带宽和灵敏度之间只能满足带宽和灵敏度中的一者。
图3C为本申请实施例提供的具有独立背腔并施加声学阻尼的多谐振频率MEMS扬声器阵列与图3A和图3B结构的频率响应曲线对比示意图；图3D为本申请实施例提供的MEMS扬声器阵列中谐振频率为2时的另一种实验结果示意图。
在一些实施例中，也可以在振膜单元10上不设置阻尼结构，如图3A所示；或者，也可以在各振膜单元10上设置阻尼结构，但各背腔30相互连通，即各振膜单元10所对应的不具有独立背腔30，如图3B所示；通过将例如图1B、图3A和图3B的结构进行仿真比较，比较结果例如图3C和图3D所示，从图中可以明显的看出，有独立背腔30并施加了声学阻尼的多谐振频率 MEMS扬声器阵列100拥有比未添加声学阻尼的多谐振频率MEMS扬声器阵列100和添加了声学阻尼但没有独立腔/后腔的多谐振频率MEMS扬声器阵列100更加平坦的响应。添加了阻尼但没有独立前/后腔的多谐振频率MEMS扬声器阵列100会出现非常低的声压级深谷。
在另一些实施例中，如图4A和图4B所示，声学阻尼件还可以为阻尼板60，阻尼板60上设置有多个通孔61，多个通孔61和振膜单元10相对设置，可以理解的是，阻尼板60上的通孔61具有阻尼功能，以通过通孔61减弱振膜单元10的声学耦合。
其中，阻尼板60上的通孔61的大小和分布可根据实际情况进行适应性设计和调节，另外，阻尼板60的材料可以为硅等半导体材料，并通过例如刻蚀小孔的工艺刻蚀形成，当阻尼板60的材料为硅等半导体材料时，阻尼板60可通过键合的方式与MEMS扬声器阵列100的基底23形成连接，示例性，在图5中，阻尼板60与基底23之间设置有键合层70，以通过键合层70实现阻尼板60与基底23之间的键合连接。
在一些实施例中，多个通孔61可以在阻尼板60上均匀分布，且各通孔61的孔径尺寸大小相等，如图4A中所示。
在另一些实施例中，多个通孔61形成至少两个通孔阵列611，不同通孔阵列611分别和振膜单元10对应设置，即一个通孔阵列611至少对应一个振膜单元10。
在一些实施例中，至少两个通孔阵列611包括第一通孔阵列611和第二通孔阵列611，第一通孔阵列611和第二通孔阵列611具有不同的通孔61数量和/或通孔61大小，以使第一通孔阵列611和第二通孔阵列611对应的振膜单元10具有不同的声学阻尼。
示例性的，如图4B中所示，至少两个通孔阵列611包括第一通孔阵列611、第二通孔阵列611、第三通孔阵列611、第四通孔阵列611、第五通孔阵列611、第六通孔阵列611，其中，各通孔阵列611的通孔61大小不同，同时各通孔阵列611的通孔61数量也不同，这样，不同通孔阵列611具有不同的声学阻尼，以减弱与其对应的振膜单元10的声学耦合。
在一些实施例中，阻尼结构为机械阻尼件80，机械阻尼件80包括覆盖至少部分振膜单元10的机械阻尼层，机械阻尼层覆盖至少一个振膜单 元10。示例性的，如图6所示，在振膜单元10上设置机械阻尼层，且机械阻尼层覆盖全部振膜单元10；当然，机械阻尼层也可以只覆盖部分振膜单元10，如图8中所示，通过在振膜单元10上设置机械阻尼层，可以减弱振膜单元10的声学耦合。
其中，机械阻尼层的材料可以为高损耗材料，例如可以为高分子材料聚对二甲苯(Parylene，简称PI)。
在一些实施例中，在振膜单元10上设置机械阻尼层的同时，还在振膜单元10背离机械阻尼层的一侧设置有阻尼网50，其中，阻尼网50可以至少覆盖一个振膜单元10，机械阻尼层也可以覆盖至少一个振膜单元10，示例性的，在图7中，在振膜单元10的一侧覆盖有机械阻尼层，在振膜单元10背离机械阻尼层的一侧设置有覆盖全部振膜单元10的阻尼网50。通过在振膜单元10上同时设置机械阻尼层和阻尼网50，可以进一步减弱振膜单元10的声学耦合，从而使MEMS扬声器阵列100能够获得更加平坦光滑的高输出声压频率响应特性。
在一些实施例中，继续参照图1B和图9所示，振膜单元10和声孔110共同围成至少两个背腔30，至少两个背腔30包括第一背腔，第一背腔对应于振膜单元阵列中的部分振膜单元10。
可以理解的是，第一背腔可以对应于一个振膜单元10单元，也可以对应于两个或者两个以上的振膜单元10，例如，在图9中，第一背腔对应于两个振膜单元10；在图1B中，第一背腔对应于振膜单元阵列中的单个振膜单元10。
在一些实施例中，各背腔30分别对应于不同的振膜单元10。例如，在图1B中，一个背腔30对应一个振膜单元10。
在一些实施例中，至少两个背腔30还包括第二背腔，第二背腔对应至少两个振膜单元10，也就是说，第二背腔对应两个或者两个以上的振膜单元10，而第一背腔可以对应一个振膜单元10，也可以对应两个或者两个以上的振膜单元10，具体可根据需要进行适应性设计，在此不做具体限制。
在一些实施例中，背腔30的数量为一个，前腔300的数量为一个、两个或者两个以上。
在另一些实施例中，背腔30的数量为至少两个；和/或，前腔300的 数量为至少两个。
在一些实施例中，前腔300为至少两个，如图10A中，各前腔300相互独立且分别对应不同振膜单元10，另外，阻尼网50覆盖各振膜单元10对应的各前腔300区域。
在一些实施例中，背腔30的数量为至少两个，前腔300的数量也为至少两个，例如，一个振膜单元10分别与一个背腔30和一个前腔300对应设置；或者，至少两个振膜单元10对应一个共用的背腔30，而各振膜单元10分别独立对应一个前腔；又或者，至少两个振膜单元10对应一个共用的前腔300，而各振膜单元10分别独立对应一个背腔30等，背腔30的数量、前腔300的数量以及振膜单元10的数量可以进行任意组合，在此，不做限制。
在另一些实施例中，如图10B所示，上盖90设置为镂空结构，镂空结构与振膜单元10对应设置，以通过镂空结构减弱振膜单元10之间的声学耦合。
在一些实施例中，第一振膜单元10和第二振膜单元10分别具有不同的形状；和/或，第一振膜单元10和第二振膜单元10分别具有不同的振膜覆盖面积。也就是说，振膜单元阵列中的各振膜单元10可以具有不同的形状，以通过改变振膜单元10的形状实现振膜单元10的谐振频率的不同；也可以使各振膜单元10的大小不同，即各振膜单元10的覆盖面积可以大小不等，以通过振膜单元10的大小实现谐振频率的不同；又或者，各振膜单元10的形状、大小均不同，以通过盖板振膜单元10的形状和大小的不同共同实现谐振频率的改变。
可以理解的是，通过使第一振膜单元10和第二振膜单元10的形状、大小等的不同，以使得不同振膜单元10具有不同的谐振频率，从而提升MEMS扬声器阵列100的带宽。
振膜单元10的类型可以包括悬臂梁式振膜单元10、固支圆膜振膜单元10中的至少一种。
在一个示例中，如图11A所示，六个振膜单元10均匀采用四个相同的三角形悬臂梁作为一个振膜单元10的平面结构，各振膜单元10的形状相同，通过使各振膜单元10的平均结构所覆盖面积的大小不同，以使得 两个振膜单元10的谐振频率不同。
在另一个示例中，如图11B所示，也采用四个相同的三角形悬臂梁作为一个振膜单元10的平面结构，振膜单元阵列具有9个振膜单元10，且其中四个振膜单元10的覆盖面积大小相等，因此，该四个振膜单元10的谐振频率相等，其他5个的谐振频率大小不等。
为了便于理解，11B中增加的三个振膜单元10可分别用第七振膜单元10、第八振膜单元10和第九振膜单元10表示。
在再一个示例中，如图12所示，各振膜单元10为固支圆膜，且各振膜单元10的平面结构的覆盖面积大小不相等，由于各固支圆膜是全封闭结构的振膜单元10，其前腔300和背腔30隔绝，这样，能够获得更平缓的低频响应。
在又一个示例中，如图13所示，振膜单元阵列集成了固支圆膜、三角形悬臂梁、正梯形悬臂梁、倒梯形悬臂梁等在平面结构上的不同形状的振膜单元10，通过改变振膜单元10在平面结构上的形状来实现不同的谐振频率。
另外，通过改变振膜单元10在平面结构上的形状、大小来实现不同谐振频率外，还可以改变厚度方向的结构实现不同的谐振频率；示例性的，如图14A和图14B所示，通过将各振膜单元10的一部分刻蚀去除，改变振膜单元10的等效质量和等效刚度，从而实现谐振频率的改变。
可以理解的是，振膜单元阵列中，不同的振膜单元10刻蚀去除的部分不同，这样，可以使得各振膜单元10具有不同的等效质量和等效刚度，从而使得各振膜单元10具有不同的谐振频率。
需要说明的是，振膜单元阵列中的振膜单元10的数量可根据需要进行设置，具体没有数量限制，示例性的，如图15所示，振膜单元阵列中有24个覆盖面积大小不等的振膜单元10，以使24个振膜单元10均具有不同的振膜频率。
在一些实施例中，MEMS扬声器阵列100还包括驱动器400，驱动器400被配置为带动振膜单元10耦合振动。
在一些实施例中，驱动器400围设于振膜单元10周向外侧，且驱动器400通过耦合结构500和振膜单元10耦合振动，如图16A中所示，其 中，驱动器400的电极可以全覆盖或者部分覆盖振动单元的周向外侧。
在一些实施例中，第一振膜单元10和第二振膜单元10分别具有不同的形状，以通过不同的形状各振膜单元10具有不同的谐振频率，如图16B中所示。
在一些实施例中，第一振膜单元10和第二振膜单元10分别具有不同的振膜覆盖面积。示例性的，在图16C中，振膜单元10包括3个振膜单元10，3个振膜单元10具有不同的振膜覆盖面积，即3个振膜单元10的平面尺寸不同，以使得各振膜单元10具有不用的谐振频率。
在一些实施例中，第一振膜单元10和第二振膜单元10分别对应不同的驱动器400的自由边界长度，以实现不同的谐振频率，如图16D中所示。
在一些实施例中，MEMS扬声器阵列100还包括质量块600，驱动器400通过质量块600带动振膜单元10耦合振动，不同振膜单元10对应的质量块600具有不同的质量，如图17A和图17B中所示，可以理解的是，通过不同质量的质量块600，可以使得各振膜单元10具有不同的谐振频率。
需要说明的是，各振膜单元10在平面结构上的形状、大小可以相同，也可以不同；示例性的，在图17C中，各振膜单元10在平面结构上的形状、大小相同，通过与各振膜单元10相对应的质量块600不同，以实现各振膜单元10的谐振频率不同。
当然，也可以在包括质量块600的基础上，通过在振膜单元10上设置阻尼结构，以实现不同的谐振频率，也就是说，上述可以改变谐振频率的各方式可以进行自由组合，在此，不做具体限制。
在一些实施例中，振膜单元阵列中的各振膜单元10沿同一方向间隔并排排列，且每相邻振膜单元10之间形成空气腔，不同振膜单元10具有不同的大小。
示例性的，如图18A和图18B所示，相邻振膜单元10之间形成了空气腔，图中L1～L9为空气腔的宽度，L0为振膜单元10的端部到基底23的距离，在本实施例中，可以通过改变振膜单元10的大小以实现不同的谐振频率，各空气腔的宽度可以相同也可以不同。其中，当L0小于30μ m时，两个空气腔可以近似为相互独立。
另外，MEMS扬声器阵列100还包括下盖，下盖设置在振膜单元10背离上盖90的一侧，且覆盖全部或部分振膜单元10；在一些实施例中，下盖充当为阻尼板60，其材料可以为硅材料。
下面实施例中，以下盖为阻尼板60为例进行说明。
图18C为阻尼板60(下盖)和上盖90的结构，例如，图18C中的a图为阻尼板60的示意图；图18C中的b图为上盖90的示意图；阻尼板60和上盖90可以与图18A中所对应的结构连接形成独立的空腔，图中的h代表气孔，该气孔可以为具有阻尼作用，以减弱振膜单元10之间的声学耦合。
在另一些实施例中，阻尼板60和上盖90的结构可以相同，如图18D中所示，可以在阻尼板60和上盖90上刻蚀多个形状以及大小相同或不同的小孔，以通过小孔实现阻尼，从而减弱振膜单元10之间的声学耦合。其中，多个小孔可以形成多个不同的小孔阵列，且各小孔阵列分别与振膜单元10对应设置。
在一些实施例中，不用振膜单元10在振膜单元10的长度方向上的延伸尺寸不同，其中，振膜单元10的长度方向和振膜单元10的排列方向相互垂直。通过使振膜单元10在长度方向上的延伸尺寸不同，以使得各振膜单元10具有不同的谐振频率。
另外，如图19A和图19B所示，可通过改变振膜单元10的长度实现不同的谐振频率，其中，阻尼板60和上盖90的形状结构可相同，且在阻尼板60和上盖90上形成阻尼孔，阻尼孔的结构形状可以与振膜单元10的形状、大小相匹配，如图19A中的a图为阻尼板60和上盖90的结构示意图；图19A中的b图为振膜单元阵列的结构示意图；或者，如图19B中的a图所示，阻尼板60和上盖90上形成的阻尼孔可以为至少两个阻尼孔阵列，相应的，如图19B中的b图所示，多个振膜单元10也可以形成相应的振膜阵列，其中，振膜阵列包括至少两个振膜单元10；以使得一个振膜阵列对应一个阻尼孔阵列，且不同的阻尼孔阵列的形状、大小可以不同。
如图20A、图20B及图20C所示，上述所有MEMS扬声器阵列100的振膜单元10厚度方向的剖面结构，包括层叠设置的结构层1、压电层2和电 极层3，其中，电极层3包括顶电极和底电极，且顶电极和底电极的材料可以为钼、铂、金等导电金属；压电层2可以为AlN及其稀土掺杂结构；结构层1的材料可以为例如硅、AlN等材料。在图20C中，压电层2包括第一电极21和第二电极22，且第一电极21为两个，两个电极分别位于电极层3的外侧；第二电极22也为两个，两个第二电极22层分别位于结构层1的相对两侧；当结构层1的材料为导电材料时，靠近结构层1一侧的电极可以省去。
另外，除压电材料振膜构成的压电MEMS扬声器阵列100外，还可以为其他类型的MEMS扬声器阵列100，例如电极材料振膜构成的静电MEMS扬声器阵列100，或者电磁材料振膜构成的电磁MEMS扬声器阵列100。
本申请实施例提供的MEMS扬声器阵列，包括基底和设置在基底上的振膜单元阵列，基底上设置有声孔，振膜单元阵列包括至少两个间隔设置的振膜单元，振膜单元对应设置于声孔内，且至少两个振膜单元具有至少两个不同的谐振频率。上述方案中，通过使至少两个振膜单元具有至少两个不同的谐振频率，这样，多个不同的谐振频率可以覆盖比较宽的工作带宽，从而在能够满足MEMS扬声器阵列的工作带宽的同时，提高MEMS扬声器阵列的发声效率。
本说明书中各实施例或实施方式采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分相互参见即可。
在本说明书的描述中，参考术语“一个实施方式”、“一些实施方式”、“示意性实施方式”、“示例”、“具体示例”、或“一些示例”等的描述意指结合实施方式或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一个实施方式或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施方式或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施方式或示例中以合适的方式结合。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并 不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (37)

  1. 一种MEMS扬声器阵列，其特征在于，包括基底和设置在所述基底上的振膜单元阵列，所述振膜单元阵列包括至少两个间隔设置的振膜单元，且至少两个振膜单元具有至少两个不同的谐振频率。
  2. 根据权利要求1所述的MEMS扬声器阵列，其特征在于，所述至少两个振膜单元包括至少一个第一振膜单元和至少一个第二振膜单元，所述第一振膜单元和所述第二振膜单元分别具有不同的谐振频率。
  3. 根据权利要求2所述的MEMS扬声器阵列，其特征在于，所述振膜单元上设置有声学阻尼件和机械阻尼件中的至少一者。
  4. 根据权利要求3所述的扬声器阵列，其特征在于，所述基底上设置有声孔，所述振膜单元对应设置于所述声孔内。
  5. 根据权利要求4所述的MEMS扬声器阵列，其特征在于，所述MEMS扬声器阵列包括所述声学阻尼件，所述声学阻尼件与所述声孔相对设置。
  6. 根据权利要求5所述的MEMS扬声器阵列，其特征在于，所述声学阻尼件设置于所述声孔的背离所述振膜单元的一侧。
  7. 根据权利要求5所述的MEMS扬声器阵列，其特征在于，所述声学阻尼件覆盖至少部分所述振膜单元。
  8. 根据权利要求5所述的MEMS扬声器阵列，其特征在于，所述声学阻尼件覆盖所有所述振膜单元的表面。
  9. 根据权利要求5所述的MEMS扬声器阵列，其特征在于，所述声学阻尼件包括阻尼网。
  10. 根据权利要求5所述的MEMS扬声器阵列，其特征在于，所述声学阻尼件为阻尼板，所述阻尼板上设置有多个通孔，多个所述通孔和所述振膜单元相对设置。
  11. 根据权利要求10所述的MEMS扬声器阵列，其特征在于，所述阻尼板为硅板。
  12. 根据权利要求10所述的MEMS扬声器阵列，其特征在于，多个所述通孔形成至少两个通孔阵列，不同所述通孔阵列分别和所述振膜单元对应设置。
  13. 根据权利要求12所述的MEMS扬声器阵列，其特征在于，至少两 个所述通孔阵列包括第一通孔阵列和第二通孔阵列，所述第一通孔阵列和所述第二通孔阵列具有不同的通孔数量和/或通孔大小，以使所述第一通孔阵列和所述第二通孔阵列对应的振膜单元具有不同的声学阻尼。
  14. 根据权利要求3所述的MEMS扬声器阵列，其特征在于，所述机械阻尼件包括覆盖至少部分所述振膜单元的机械阻尼层，所述机械阻尼层覆盖至少一个所述振膜单元。
  15. 根据权利要求4所述的MEMS扬声器阵列，其特征在于，所述振膜单元和所述声孔的孔壁共同围成背腔。
  16. 根据权利要求15所述的MEMS扬声器阵列，其特征在于，所述振膜单元和所述声孔共同围成至少两个背腔，所述至少两个背腔包括第一背腔，所述第一背腔对应于所述振膜单元阵列中的部分所述振膜单元。
  17. 根据权利要求16所述的MEMS扬声器阵列，其特征在于，所述第一背腔对应于所述振膜单元阵列中的单个所述振膜单元。
  18. 根据权利要求17所述的MEMS扬声器阵列，其特征在于，各所述背腔分别对应于不同所述振膜单元。
  19. 根据权利要求16所述的MEMS扬声器阵列，其特征在于，所述至少两个背腔还包括第二背腔，所述第二背腔对应至少两个所述振膜单元。
  20. 根据权利要求15所述的MEMS扬声器阵列，其特征在于，还包括上盖，所述上盖连接于所述基底，所述上盖设置于所述振膜单元的背离所述背腔的一侧，且所述上盖和所述振膜单元围成至少一个前腔。
  21. 根据权利要求20所述的MEMS扬声器阵列，其特征在于，所述背腔的数量为至少两个；和/或，所述前腔的数量为至少两个。
  22. 根据权利要求21所述的MEMS扬声器阵列，其特征在于，所述前腔为至少两个，且各所述前腔分别对应不同所述振膜单元。
  23. 根据权利要求2所述的MEMS扬声器阵列，其特征在于，所述第一振膜单元和所述第二振膜单元分别具有不同的形状；和/或，所述第一振膜单元和所述第二振膜单元分别具有不同的振膜覆盖面积。
  24. 根据权利要求23所述的MEMS扬声器阵列，其特征在于，所述振膜单元的类型包括悬臂梁式振膜单元和固支圆膜振膜单元中的至少一种。
  25. 根据权利要求2所述的MEMS扬声器阵列，其特征在于，还包括驱 动器，所述驱动器被配置为带动所述振膜单元耦合振动。
  26. 根据权利要求25所述的MEMS扬声器阵列，其特征在于，所述驱动器围设于所述振膜单元周向外侧，且所述驱动器通过耦合结构和所述振膜单元耦合振动。
  27. 根据权利要求26所述的MEMS扬声器阵列，其特征在于，所述第一振膜单元和所述第二振膜单元分别具有不同的振膜覆盖面积；和/或，
    所述第一振膜单元和所述第二振膜单元分别对应不同的驱动器自由边界长度；和/或，
    所述第一振膜单元和所述第二振膜单元分别具有不同的形状。
  28. 根据权利要求25所述的MEMS扬声器阵列，其特征在于，还包括质量块，所述驱动器通过所述质量块带动所述振膜单元耦合振动，不同振膜单元对应的所述质量块具有不同的质量。
  29. 根据权利要求1或2所述的MEMS扬声器阵列，其特征在于，所述振膜单元阵列中的各所述振膜单元沿同一方向间隔并排排列，且每相邻所述振膜单元之间形成空气腔，不同所述振膜单元具有不同的大小。
  30. 根据权利要求29所述的MEMS扬声器阵列，其特征在于，不同所述振膜单元在排列方向上具有不同厚度；
    和/或，
    不同所述振膜单元在所述振膜单元的长度方向上的延伸尺寸不同，其中，所述振膜单元的长度方向和所述振膜单元的排列方向相互垂直。
  31. 根据权利要求1至3中任一项所述的MEMS扬声器阵列，其特征在于，所述振膜单元阵列中的各所述振膜单元的谐振频率依次递增，且依照谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于180度。
  32. 根据权利要求31所述的MEMS扬声器阵列，其特征在于，根据谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于120度。
  33. 根据权利要求32所述的MEMS扬声器阵列，其特征在于，根据谐振频率顺序排列的各所述振膜单元中，相邻两个所述振膜单元的振动相位差小于90度。
  34. 根据权利要求1-3中任一项所述的MEMS扬声器阵列，其特征在于，所述MEMS扬声器阵列对应的输入信号端口数小于所述振膜单元的数量。
  35. 根据权利要求34所述的MEMS扬声器阵列，其特征在于，所述MEMS扬声器阵列对应的输入信号端口数为1。
  36. 根据权利要求3所述的MEMS扬声器阵列，其特征在于，不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之前大于120度；不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之后小于120度。
  37. 根据权利要求36所述的MEMS扬声器阵列，其特征在于，不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之前大于90度；不同所述振膜单元的振动相位差在加入所述声学阻尼件和所述机械阻尼件中的至少一者之后小于90度。
PCT/CN2023/112681 2022-09-08 2023-08-11 Mems扬声器阵列 WO2024051441A1 (zh)

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Publication number Priority date Publication date Assignee Title
US20170048623A1 (en) * 2015-08-10 2017-02-16 Knowles Electronics, Llc Dual band mems acoustic device
CN211240071U (zh) * 2019-10-23 2020-08-11 四川瑞昊微电子科技有限公司 一种振膜与压电片复合的扬声器
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