CN117560614A

CN117560614A - Electroacoustic transducer, manufacturing method thereof and electronic equipment

Info

Publication number: CN117560614A
Application number: CN202210927020.8A
Authority: CN
Inventors: 王磊; 何云乾; 彭勃; 倪正阳; 许超; 朱统; 舒迎飞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-08-03
Filing date: 2022-08-03
Publication date: 2024-02-13

Abstract

The application relates to the technical field of terminals, in particular to an electroacoustic transducer, a manufacturing method thereof and electronic equipment. The electroacoustic transducer comprises a substrate, a housing and at least two microelectromechanical units arranged between the substrate and the housing. Each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, wherein the vibration components in at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate; each vibration assembly is electrically connected with a processing circuit on the substrate; an acoustic cavity of the micro-electromechanical unit is formed on one side, facing the substrate, of the vibration component in each micro-electromechanical unit, and the acoustic cavity is communicated with the external space for passing through of sound waves. The acoustic cavity of each micro-electromechanical unit can be conducted with the external space, so that the sound wave can be conducted out, and the low-frequency performance and the acoustic sensitivity of the device are improved. The additional sound guide channel is not required to be arranged, the size advantage of the micro-electromechanical unit in the thickness direction can be utilized, and the overall size of the device is not increased.

Description

Electroacoustic transducer, manufacturing method thereof and electronic equipment

Technical Field

The application relates to the technical field of terminals, in particular to an electroacoustic transducer, a manufacturing method thereof and electronic equipment.

Background

Microelectromechanical systems (micro electro mechanical systems, MEMS) are electroacoustic transducers that utilize the principles of microelectromechanical systems technology. Unlike conventional electroacoustic transducers, mems acoustic transducers are manufactured by micro-nano machining methods. The loudspeaker of the micro-electromechanical system acoustic transducer adopts piezoelectric materials as a driving unit, has the advantages of small size, thin thickness, light weight, good performance consistency and the like compared with a moving coil loudspeaker, and is very suitable for being applied to small consumer electronic products such as headphones and the like.

Wherein, single micro-electromechanical system sound transducer is limited by amplitude and vibrating area, and air promotes the volume to be limited, leads to its acoustic performance to not satisfy the in-service use requirement. The combined acoustic transducer of the multiple micro-electromechanical systems can improve the whole air pushing volume and solve the problem of insufficient performance of the acoustic transducer of the single micro-electromechanical system. However, the electroacoustic transducer of the current mems needs to be provided with a separate acoustic channel, which is not beneficial to the miniaturization of the device.

Disclosure of Invention

The application provides an electroacoustic transducer, a preparation method thereof and electronic equipment, integrates a plurality of micro-electromechanical units to sound, does not need to set an independent sound guide channel, and is beneficial to reducing the size of a device.

In a first aspect, the present application provides an electroacoustic transducer that can be applied to sound generating devices, such as headphones, to convert electrical energy into acoustic energy. The electroacoustic transducer comprises a substrate, a housing and at least two microelectromechanical units. The substrate is provided with a processing circuit, and the shell is covered on the substrate, so that a containing cavity which can contain the micro-electromechanical unit and the processing circuit can be formed between the shell and the substrate. And the shell is also provided with a sound outlet communicated with the accommodating cavity, and sound emitted by the micro-electromechanical unit can be emitted through the sound outlet. Each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, the vibration components respectively included in at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate, so that the size advantage of the micro-electromechanical units in the thickness direction can be utilized. Each vibration assembly is electrically connected to processing circuitry on the substrate and is capable of receiving audio signals from the processing circuitry. An acoustic cavity of the micro-electromechanical unit is formed on one side, facing the substrate, of the vibration component in each micro-electromechanical unit, and the acoustic cavity is communicated with the external space for passing through of sound waves.

Wherein the at least two microelectromechanical units comprise a first microelectromechanical unit and at least one second microelectromechanical unit. The vibration component included in the first micro-electromechanical unit is located between the vibration component and the substrate included in the at least one second micro-electromechanical unit. For the first micro-electromechanical unit, the first micro-electromechanical unit is provided with an acoustic guiding structure for communicating the acoustic cavity with the external space; or, the base plate is provided with an acoustic hole to communicate the acoustic cavity with the external space. For any one of the second micro-electromechanical units, the second micro-electromechanical unit is provided with an acoustic guiding structure to communicate the acoustic cavity with the external space. For different micro-electromechanical units, different sound guide structures are arranged, and audio signals with different frequencies can be loaded on the different micro-electromechanical units so as to meet the requirements of different sounding frequency bands of the device.

In one possible implementation, the sound guiding structure may be a slit extending through the vibration assembly, the slit being sized to allow sound waves to pass through. Specifically, the width of the slit is 10 μm or more. In another possible implementation, the sound guiding structure may be a sound guiding hole extending through the support structure, the sound guiding hole also being sized to be able to pass sound waves. Specifically, the width of the sound guiding hole is greater than or equal to 0.01mm ² 。

In some possible implementations, slits are provided on each vibration assembly to form an cantilever beam structure that can vibrate under the drive of electrical energy to push air into. The cantilever beam structure can reduce equivalent rigidity of the vibration sound-emitting cavity, improve acoustic sensitivity and widen corresponding bandwidth of high frequency. When the width of the kerf is smaller, the vibration assembly is equivalent to a sealing structure or an approximately sealing structure, and the vibration assembly is ensured to have smaller sound leakage below 100 Hz. When the width of the slit is relatively large, the slit may form the above-mentioned sound guiding structure located on the vibration unit.

The slit may be U-shaped, and the vibration component may form two cantilever beam structures. Alternatively, the slit may be i-shaped, and the vibration assembly may form an cantilever structure.

In some possible implementations, the support structure includes an annular support that is supported at the edge of the vibration assembly. The annular support is supported on the edge of the vibration assembly, and an acoustic cavity of the micro-electromechanical unit is formed between the annular support and the vibration assembly. The annular support is positioned on the peripheral side of the acoustic cavity of the microelectromechanical unit, and the vibration assembly is positioned on the top side of the acoustic cavity of the microelectromechanical unit.

Possibly, at least two annular supports are stacked one on top of the other in the first direction. Between any two adjacent annular supports, the annular support at the top is fixed to the side of the annular support at the bottom, which is far from the substrate. By superposing the annular supporting pieces, the at least two micro-electromechanical units are superposed along the first direction, so that the advantage of the micro-electromechanical units in the thickness direction can be utilized, the thickness of the electroacoustic transducer in the first direction can be reduced, and the size of the electroacoustic transducer in the circumferential direction of the micro-electromechanical units can be reduced.

In order to enhance the fixing effect of the annular supporting members, a buried groove may be provided between any two adjacent annular supporting members on one side of the annular supporting member located at the bottom facing away from the substrate, and the annular supporting member located at the top is fixed in the buried groove. The arrangement of the buried groove is beneficial to positioning and mounting in the structure packaging process, simplifies the packaging process and improves the packaging yield.

Further, an auxiliary adhesive may be provided in the buried groove, by means of which the annular support at the top can be fixed into the buried groove. The types of auxiliary binders vary for the structures of the different microelectromechanical units. The auxiliary adhesive may include an adhesive when each vibration assembly is connected to a processing circuit on the substrate through an external connection wire, respectively. When each vibration assembly is connected with the processing circuit on the vibration assembly through the conductive column penetrating through the supporting structure, the auxiliary adhesive comprises an adhesive and conductive adhesive. The depth of the buried groove is smaller than 100 mu m, and the strength of the supporting structure can be ensured while the buried groove packaging is realized through limiting the depth range of the buried groove. It will be appreciated that when the vibration assembly is connected to the processing circuitry thereon by means of conductive posts extending through the support structure, this helps to reduce the packaging area of the electroacoustic transducer in a direction parallel to the substrate.

In other possible implementations, at least two annular supports are arranged around one another from inside to outside, i.e. between any two adjacent annular supports, the annular support on the outside being arranged around the annular support on the inside.

Between any two adjacent annular supports, the height of the annular support on the outer side is greater than the height of the annular support on the inner side. Such an arrangement enables the vibrating assemblies supported by the two annular supports to be arranged in sequence along the first direction.

In some possible implementations, the vibration assembly includes a substrate, and a first electrode, a piezoelectric material layer, and a second electrode sequentially stacked on the substrate; the substrate is fixed on the supporting structure; the first electrode and the second electrode are electrically connected to processing circuitry on the substrate, respectively. The first electrode and the second electrode can form an electric field in an electrified state, and the piezoelectric material layer in the electric field can generate structural deformation so as to push air to sound.

The piezoelectric material layer is made of one or a combination of at least two of lead zirconate titanate, aluminum nitride, scandium-doped aluminum nitride and zinc oxide.

In some possible implementation manners, the mesh cloth covering the sound outlet is arranged at the sound outlet, and the mesh cloth can play a role in dust prevention. When the sound transmission holes are formed in the substrate, mesh cloth covering the sound transmission holes can be arranged at the sound transmission holes so as to play a role in dust prevention and protection.

In a second aspect, the application further provides an electronic device, which further includes a housing, a signal input end, and any electroacoustic transducer in the foregoing technical solutions. The shell is provided with a sound outlet nozzle, and the electroacoustic transducer is arranged in the shell and is positioned at the sound outlet nozzle. The signal output is electrically connected to a substrate of the electroacoustic transducer through which a first audio signal may be applied to a vibrating assembly in the microelectromechanical unit. The electroacoustic transducer comprises at least two micro-electromechanical units, and can apply audio signals with different frequencies to different micro-electromechanical units through the substrate so as to meet the sounding requirement of the electronic equipment. The electroacoustic transducer has higher sensitivity in the middle-high frequency band, and can improve the tone quality of the electronic equipment. The stacking of the micro-electromechanical units can realize smaller size of the device, is more suitable for being placed at the sound outlet of the electronic equipment, and further can improve the sound acquisition sensitivity of a consumer in use, namely, the high-frequency acoustic sensitivity in the electronic equipment can be improved.

In some possible implementations, the speaker further includes a moving coil speaker disposed within the housing, the moving coil speaker electrically connected to the signal input, the signal input operable to apply a second audio signal to the moving coil speaker. Wherein the frequency of the first audio signal is higher than the frequency of the second audio signal.

In a third aspect, the present application further provides a method for preparing an electroacoustic transducer, which may be used to prepare an electroacoustic transducer in the above technical solution. The preparation method can comprise the following steps:

providing a substrate, and arranging a processing circuit on the substrate; at least two micro electromechanical units are arranged on the substrate; each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, and the vibration components respectively included in at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate; each vibration component is electrically connected with the processing circuit respectively; in each micro-electromechanical unit, an acoustic cavity of the micro-electromechanical unit is formed on one side of the vibration component, facing the substrate, and the acoustic cavity is communicated with the external space for passing through acoustic waves;

fixing the housing to the substrate to encapsulate the at least two microelectromechanical units and the processing circuitry within a containment cavity between the housing and the substrate; the housing is provided with an acoustic port in communication with the receiving chamber.

At least two micro-electromechanical units can be stacked along a first direction, namely, between two adjacent micro-electromechanical units, wherein one micro-electromechanical unit is arranged on one side of the other micro-electromechanical unit away from the substrate. When the at least two microelectromechanical units comprise two microelectromechanical units stacked along a first direction; providing at least two microelectromechanical units on a substrate arrangement comprises:

Fixing a support structure of one of the micro-electromechanical units to the substrate;

a buried groove is arranged on one side of the micro-electromechanical unit, which is away from the substrate;

the support structure of the other microelectromechanical unit is fixed into the buried trench.

In some possible implementations, after the side of the microelectromechanical unit facing away from the substrate is provided with the buried groove and before the support structure of the other microelectromechanical unit is fixed in the buried groove, the preparation method may further include the steps of: and coating auxiliary adhesive in the buried groove.

In some possible implementations, after the housing is fixed to the substrate, the method of preparing may further include the steps of: a mesh cloth covering the sound outlet is arranged.

Drawings

Fig. 1 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application;

fig. 2a and fig. 2b are schematic cross-sectional views of an electroacoustic transducer according to an embodiment of the present application;

FIG. 2c is a graph of total sound pressure level versus cross-sectional area of an aperture for a sound guiding structure in an electroacoustic transducer according to an embodiment of the present application;

fig. 3a to 3g are schematic cross-sectional views of an electroacoustic transducer according to an embodiment of the present application;

fig. 4a is a schematic structural diagram of a support structure in an electroacoustic transducer according to an embodiment of the present application;

Fig. 4b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 5a and 5b are schematic views of a part of the structure of an electroacoustic transducer according to an embodiment of the present application;

fig. 6a is a schematic structural diagram of a vibration component in an electroacoustic transducer according to an embodiment of the present application;

fig. 6b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 7a is a schematic structural diagram of a vibration component in an electroacoustic transducer according to an embodiment of the present application;

fig. 7b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 8a is a schematic structural diagram of a vibration component in an electroacoustic transducer according to an embodiment of the present application;

fig. 8b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 9a is a schematic structural diagram of a vibration component in an electroacoustic transducer according to an embodiment of the present application;

fig. 9b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

Fig. 11a is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 11b is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 11c is a schematic structural diagram of a microelectromechanical unit in an electroacoustic transducer according to an embodiment of the present application;

fig. 12 is a schematic cross-sectional structure of an electroacoustic transducer according to an embodiment of the present disclosure;

fig. 13a to 13h are schematic cross-sectional views of an electroacoustic transducer according to an embodiment of the present application;

fig. 14a and 14b are schematic structural diagrams of a vibration assembly in an electroacoustic transducer according to an embodiment of the present application;

fig. 15a to 15d are schematic cross-sectional views of an electroacoustic transducer according to an embodiment of the present application;

fig. 16a is a schematic structural diagram of an electronic device according to an embodiment of the present application;

fig. 16b is a schematic cross-sectional view of a part of the structure of an electronic device according to an embodiment of the present disclosure;

fig. 16c is a schematic cross-sectional view of a part of the structure of an electronic device according to an embodiment of the present disclosure;

fig. 17a is a schematic structural diagram of an electronic device according to an embodiment of the present application;

fig. 17b is a schematic cross-sectional view of a part of the structure of an electronic device according to an embodiment of the present disclosure;

Fig. 17c is a schematic cross-sectional view of a part of the structure of an electronic device according to an embodiment of the present disclosure;

fig. 18 is a process schematic diagram of a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 19a and 19b are schematic structural views of a substrate of an electroacoustic transducer according to an embodiment of the present application;

fig. 20 is a process schematic diagram of a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 21a and 21b are schematic structural diagrams during a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 22a and 22b are schematic structural diagrams during a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 23 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 24 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 25 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 26 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 27 is a process schematic diagram of a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

Fig. 28a and 28b are schematic structural diagrams during a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 29a and 29b are schematic structural diagrams during a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 30 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 31 is a schematic structural diagram of an electroacoustic transducer according to an embodiment of the present application during a manufacturing method;

fig. 32 is a schematic structural diagram of an electroacoustic transducer manufactured by a manufacturing method of an electroacoustic transducer according to an embodiment of the present application;

fig. 33 is a schematic structural diagram of an electroacoustic transducer manufactured by the manufacturing method of the electroacoustic transducer according to the embodiment of the present application;

fig. 34 is a process schematic diagram of a method for manufacturing an electroacoustic transducer according to an embodiment of the present application;

fig. 35 is a schematic structural diagram of an electroacoustic transducer manufactured by using the manufacturing method of the electroacoustic transducer according to the embodiment of the present application;

fig. 36 is a schematic structural diagram of an electroacoustic transducer manufactured by using the manufacturing method of the electroacoustic transducer according to the embodiment of the present application.

Detailed Description

At present, micro-electromechanical system electroacoustic transducers are often adopted in loudspeaker structures for small electronic products such as headphones. The electroacoustic transducer is characterized in that the piezoelectric material drives the vibrating membrane to vibrate and sound, and the performance of the electroacoustic transducer can be improved through the integration of a plurality of micro-electromechanical system units. However, in the technology, the equivalent rigidity of the sound guide cavity of the micro-electromechanical system is high, which is not beneficial to the performance improvement of the micro-electromechanical system. And the integrated structure of a plurality of micro-electromechanical system units needs more sound guide channels, which is unfavorable for the miniaturization of the electroacoustic transducer.

Based on the above, the embodiment of the application provides an electroacoustic transducer, a preparation method thereof and an earphone. The electroacoustic transducer integrates a plurality of micro-electromechanical systems, and can achieve miniaturization of devices and good acoustic performance.

The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include, for example, "one or more" such forms of expression, unless the context clearly indicates to the contrary.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

As shown in fig. 1, an electroacoustic transducer 10 provided in an embodiment of the present application includes a substrate 1 and a housing 2 fixed to the substrate 1. The substrate 1 is provided with a processing circuit, and the electroacoustic transducer 10 can be electrically connected with the processing circuit through a bonding pad 11 on the substrate 1, and further is electrically connected with other electric devices through the processing circuit to realize signal interaction. The housing 2 is covered on the substrate 1, and a containing cavity A is formed between the housing 2 and the substrate 1. At least two micro-electromechanical units 3 are arranged in a containing cavity A formed between the shell 2 and the substrate 1, and the micro-electromechanical units 3 are used for vibrating and sounding. The casing 2 may protect the micro-electromechanical unit 3, and may be made of metal, ceramic, plastic, etc. A sound outlet k is provided in the housing 2, and penetrates the housing 2 to communicate with the accommodation chamber a, through which sound emitted from the micro-electromechanical unit 3 can be transmitted. The position of the sound outlet k is not limited, and may be set at any position of the housing 2, for example, at the top or any one side of the housing 2, as required. In the present embodiment, the sound outlet k is illustratively provided at one side of the housing 2. In connection with the state shown in fig. 1, a three-dimensional coordinate reference may be established, the first direction Z being the height direction of the electroacoustic transducer 10, the second direction X being the length direction of the electroacoustic transducer 10, and the third direction Y being the width direction of the electroacoustic transducer 10.

Illustratively, as a cross-sectional structure of an electroacoustic transducer 10 illustrated in fig. 2a, two microelectromechanical units 3 are arranged in a receiving cavity a, the two microelectromechanical units 3 being stacked along a first direction Z, which is perpendicular to the substrate 1, which may be regarded as the height direction of the electroacoustic transducer 10. Each micro-electromechanical unit 3 comprises a vibrating assembly 31 and a support structure 32. Each vibration assembly 31 is electrically connected with the bonding pad 11 on the substrate 1 through the connection wire 4, and the vibration assembly 31 can be deformed under electric driving to push air to sound. The support structure 32 of each micro-electromechanical unit 3 may provide support for the vibration assemblies 31 such that two vibration assemblies 31 can be arranged in sequence in the first direction Z. The space of the side of each vibration component 31 facing the substrate 1 is the acoustic cavity Q of the micro electromechanical unit 3 corresponding to the vibration component 31. In fig. 2a, in a bottom-located micro-electromechanical unit 3, a vibrating assembly 31, a support structure 32 and a substrate 1 form an acoustic cavity Q of the micro-electromechanical unit 3. In the microelectromechanical unit 3 at the top, the vibrating assembly 31, the support structure 32 and the microelectromechanical unit 3 at the bottom form the acoustic cavity Q of the microelectromechanical unit 3. The electroacoustic transducer 10 provided in the embodiment of the application is equivalent to stacking a plurality of micro-electromechanical units 3 in sequence along the first direction Z, and can effectively utilize the advantage of thinner thickness of a single micro-electromechanical unit 3, thereby being beneficial to realizing miniaturization of devices. The superposition of the micro-electromechanical units 3 can improve the acoustic sensitivity of the electroacoustic transducer 10, and the high-frequency response bandwidth can be expanded to be more than 20 kHz.

Wherein the at least two micro-electromechanical units 3 may comprise a first micro-electromechanical unit and at least one second micro-electromechanical unit, and the vibration component 31 of the first micro-electromechanical unit is located between the vibration component 31 of the at least one second micro-electromechanical unit and the substrate 1. Taking the structure of fig. 2a as an example, the microelectromechanical unit 3 at the bottom is the first microelectromechanical unit, and the microelectromechanical unit 3 at the top is the second microelectromechanical unit. Taking the structure of fig. 2b as an example, the microelectromechanical unit 3 closest to the substrate 1 is the first microelectromechanical unit, and the two microelectromechanical units 3 located on the side of the first microelectromechanical unit away from the substrate 1 are both the second microelectromechanical units. For the first micro-electromechanical unit, the acoustic cavity Q of the first micro-electromechanical unit is formed by the first micro-electromechanical unit and the substrate 1, and in order to communicate the acoustic cavity Q with the external space, an acoustic guiding structure may be provided on the first micro-electromechanical unit to communicate the acoustic cavity Q with the external space. Alternatively, an acoustic hole may be provided on the substrate 1 to communicate the acoustic cavity Q with the external space. For any one of the second micro-electromechanical units, an acoustic guiding structure is arranged on each of the second micro-electromechanical units to communicate the acoustic cavity Q with the external space.

Wherein when the sound guiding structure is an aperture, the cross-sectional area of the aperture needs to be capable of passing sound waves. In particular, the cross-sectional area of the holes should be greater than 0.01mm ² . For example, the cross-sectional area of the hole is 0.01mm ² 、0.1mm ² 、0.2mm ² Etc. Taking the sound guiding structure as an example of the hole, as shown in fig. 2c, the total sound pressure level through the sound wave gradually increases as the cross-sectional area of the hole increases. When the cross-sectional area of the hole reaches 0.01mm ² The sound pressure level of the sound wave passing through the hole can reach 57dB. When the cross-sectional area of the hole reaches 0.5mm ² Above, the total sound pressure level of the sound wave passing through the hole can reach 70dB, and the sound wave is nearly saturated, so that an effective sound wave conduction effect can be realized. When the sound guiding structure is a slit, the width of the slit needs to be capable of passing sound waves. Specifically, the width of the slit should be greater than 10 μm. For example, the slit width is 10 μm, 20 μm, 100 μm, etc. The length of the slit is generally greater than the width, so the area of the slit is also generally greater than or equal to 0.01mm ² Can also achieve goodIs not illustrated here.

Next, a specific structure of the electroacoustic transducer 10 provided in the embodiment of the present application will be described by taking two microelectromechanical units 3 as an example.

As shown in fig. 3a, in a first direction Z, the two micro-electromechanical units 3 are a micro-electromechanical unit 3a and a micro-electromechanical unit 3b, respectively. The micro-electromechanical unit 3a includes a vibration component 31a and a support structure 32a for supporting the vibration component 31a, the support structure 32a is fixed on the substrate 1, the vibration component 31a is disposed at the top end of the support structure 32a, and an acoustic cavity Q1 of the micro-electromechanical unit 3a is formed between the support structure 32a, the vibration component 31a and the substrate 1. The micro-electromechanical unit 3a is a full-frequency sound generating unit, and the vibration component 31a is of a sealing structure or an approximately sealing structure, so that sound leakage of the vibration component 31a below 100Hz is ensured to be less than 10dB. The vibration assembly 31a is an approximately sealed structure, for example, the vibration assembly 31a has micro-slits having a width of less than 20 μm. The substrate 1 is provided with a sound-transmitting hole t which connects the acoustic cavity Q1 to an external space, and sound waves can be transmitted to the external space through the sound-transmitting hole t, which is a space of the substrate 1 on a side away from the vibration member 31 a. The sound pressure in the sound cavity Q1 can be balanced through the sound transmission hole t, and the acoustic sensitivity is improved.

The micro-electromechanical unit 3b includes a vibration component 31b and a support structure 32b for supporting the vibration component 31b, the support structure 32b is fixed to a support structure 32a of the micro-electromechanical unit 3a, the vibration component 31b is disposed at the top end of the support structure 32b, and an acoustic cavity Q2 of the micro-electromechanical unit 3b is formed among the support structure 32b, the vibration component 31b and the micro-electromechanical unit 3 a. The micro electromechanical unit 3b is a medium-high frequency sound generating unit. A slit f2 is provided in the vibration module 31b, and the slit f2 connects the acoustic chamber Q2 to an external space, which is a space of the vibration module 31b on a side away from the vibration module 31a, through which the acoustic wave can be transmitted to the external space.

In operation, audio signals may be loaded on different micro-electromechanical units 3. In particular, the frequency of the audio signal loaded on the micro-electromechanical unit 3a may be smaller than the frequency of the audio signal loaded on the micro-electromechanical unit 3b, so that the sound pressure level between the audio signals with different frequencies can be effectively balanced, which is beneficial to improving the acoustic corresponding balance of the electroacoustic transducer 10.

As shown in fig. 3b, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 3 a. The difference is that, with respect to the micro-electromechanical unit 3a, a slit f1 is provided on the vibration member 31a, the slit f1 connects the acoustic chamber Q1 to an external space, which is a space between the vibration member 31a and the vibration member 31b, through which the acoustic wave can be transmitted to the external space. The micro-electromechanical unit 3a and the micro-electromechanical unit 3b may be middle-high frequency sounding units, and may be loaded with the same middle-high frequency audio signals.

As shown in fig. 3c, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 3 a. The difference is that, for the micro-electromechanical unit 3a, a sound guiding hole d1 is provided on the support structure 32a, the sound guiding hole d1 connects the sound cavity Q1 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d1, and the external space is the accommodation cavity a. The micro-electromechanical unit 3a may be an all-frequency sound generating unit, and the vibration component 31a is in a sealing structure or an approximately sealing structure, so that sound leakage of the vibration component 31a below 100Hz is ensured to be less than 10dB. The micro electromechanical unit 3b may be a medium-high frequency sound generating unit.

As shown in fig. 3d, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 3 a. The difference is that, for the micro-electromechanical unit 3b, a sound guiding hole d2 is provided on the support structure 32b, the sound guiding hole d2 connects the sound cavity Q2 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d2, and the external space is the accommodation cavity a.

As shown in fig. 3e, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 3 a. The difference is that, for the micro-electromechanical unit 3a, a sound guiding hole d1 is provided on the support structure 32a, the sound guiding hole d1 connects the sound cavity Q1 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d1, and the external space is the accommodation cavity a. For the micro electromechanical unit 3b, an acoustic port d2 is provided on the support structure 32b, the acoustic port d2 connects the acoustic cavity Q2 with an external space, and the acoustic wave can be transmitted to the external space through the acoustic port d2, and the external space is the accommodation cavity a. The micro-electromechanical unit 3a and the micro-electromechanical unit 3b can be full-frequency sounding units, and the vibration component 31a and the vibration component 31b are of sealing structures or approximate sealing structures, so that sound leakage of the vibration component 31a and the vibration component 31b below 100Hz is ensured to be less than 10dB.

As shown in fig. 3f, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 3 a. The difference is that the mesh cloth 6 covering the sound-transmitting holes t is arranged outside the sound-transmitting holes t, and the mesh cloth 6 can play a role in dust prevention and protection.

As shown in fig. 3g, the structure of the microelectromechanical unit 3a and the microelectromechanical unit 3b is similar to that in fig. 3 f. The difference lies in that the sound outlet k on the shell 2 is arranged on the top surface, the mesh cloth 6 covering the sound outlet k is arranged outside the sound outlet k, and the mesh cloth 6 can play a role in dust prevention and protection.

It should be understood that the external space is referenced to the acoustic cavity Q. For the micro electromechanical unit 3a, the space on the side of the vibration member 31a away from the acoustic cavity Q1, the space on the side of the support structure 32a away from the acoustic cavity Q1, and the space on the side of the substrate 1 away from the acoustic cavity Q1 all belong to the external space. For the micro-electromechanical unit 3b, the space on the side of the vibration component 31b away from the acoustic cavity Q2, the space on the side of the support structure 32b away from the acoustic cavity Q2, and the space on the side of the micro-electromechanical unit 3b away from the acoustic cavity Q2 all belong to the external space.

As shown in fig. 3a to 3g, the acoustic cavity Q of each micro-electromechanical unit 3 can be conducted with an external space, so that the acoustic wave can be conducted out, and the low-frequency performance of the device is improved. In addition, the structure can balance the pressure in the acoustic cavity Q of the micro-electromechanical unit 3 and improve the acoustic sensitivity of the device. When a plurality of micro-electromechanical units 3 are stacked along the first direction Z, no additional sound guide channel is required, and the size advantage of the micro-electromechanical units 3 in the thickness direction can be utilized without increasing the overall size of the device.

As shown in fig. 4a, in the electroacoustic transducer 10 of the embodiment of the present application, the support structure 32 of each microelectromechanical unit 3 includes an annular support 321, the annular support 321 has a hollow cylindrical shape, and the annular support 321 may be supported on an edge of the vibration assembly 31. As shown in fig. 4b, the vibrating assembly 31 may be fixed to the top of the ring-shaped support 321 to constitute the micro-electromechanical unit 3. The vibration element 31 corresponds to the top side of the acoustic chamber Q of the micro-electromechanical unit 3, and the annular support 321 surrounds the periphery of the acoustic chamber Q.

As illustrated in fig. 5a and 5b, which are schematic internal structures of an electroacoustic transducer 10, a kerf q is provided on each vibrating element 31, which kerf q enables the vibrating element 31 to be cut into at least one cantilever structure. One end of the cantilever beam type structure is fixed, and the other end is free. For one micro-electromechanical unit 3, the cantilever beam structure is mechanically free along the extension direction of the cantilever beam structure, so that the equivalent rigidity of the acoustic cavity Q of the micro-electromechanical unit 3 can be reduced, and the acoustic low-frequency performance of the micro-electromechanical unit 3 can be improved. When the width of the slit Q of the vibration element 31 of one micro-electromechanical unit 3 is large enough, the slit Q can serve as an acoustic guiding structure of the acoustic cavity Q of the micro-electromechanical unit 3, and the acoustic cavity Q is conducted with the external space, so that the acoustic wave can pass through conveniently. In fig. 5a, an acoustic port t is provided in the substrate 1 in order to connect the acoustic cavity Q of the bottom microelectromechanical element 3 to the external space. In fig. 5b, in the mems element 3 at the bottom, the slit Q of the vibrating element 31 is large enough to connect the acoustic cavity Q of the mems element 3 to the space at the top of the vibrating element 31, so that the substrate 1 does not need to be provided with an acoustic hole t.

In some embodiments, the structure of the vibration assembly 31 may be as shown with reference to fig. 6 a. The vibration assembly 31 is divided into a support area B1 and a vibration area B2. The vibration area B2 is an area within a dashed frame, the support area B1 surrounds the circumference of the vibration area B2, and the support area B1 is fixed to the support structure 32, so that the vibration assembly 31 can be fixed to the support structure 32, and the support structure 32 provides support to the vibration assembly 31. Wherein the support region B1 covers at least a partial area of the top of the support structure 32.

In fig. 6a, the slit q is i-shaped, and divides the vibration assembly 31 of the vibration region B2 into two opposing cantilever beam structures. The cross-sectional structure of the micro-electromechanical unit 3 with the vibration assembly 31 shown in fig. 6a can be seen with reference to fig. 6b, the slits q allowing the vibration assembly 31 to form two opposite cantilever beam structures, each cantilever beam structure being fixed at one end to the support structure 32 and free at the other end.

Alternatively, the structure of the vibration assembly 31 may be as shown with reference to fig. 7 a. In fig. 7a, the slit q is U-shaped, and the slit q divides the vibration assembly 31 of the vibration region B2 into one cantilever beam structure. The cross-sectional structure of the micro-electromechanical unit 3 with the vibration assembly 31 shown in fig. 7a can be seen with reference to fig. 7b, the slit q forming the vibration assembly 31 into an cantilever structure with one end fixed to the support structure 32 and the other end free.

In other embodiments, the structure of the vibration assembly 31 may be as shown with reference to fig. 8 a. In fig. 8a, the support areas B1 of the vibration assembly 31 are located at both ends of the vibration area B2. The slit q is linear, and divides the vibration component 31 of the vibration area B2 into two parts, and each part of the vibration component 31 forms a cantilever beam structure. The top view of the micro-electromechanical unit 3 with the vibration assembly 31 shown in fig. 8a can be seen with reference to fig. 8b, each cantilever structure being fixed at one end to the support structure 32 and free at the other end. It should be noted that the width of the vibration assembly 31 needs to be smaller than the width of the hollow structure of the support structure 32, so that the dimension of the vibration assembly 31 in the width direction is accommodated in the dimension range of the hollow structure of the support structure 32 in the width direction, and the cantilever structure can realize the movement of the free end.

Alternatively, as shown in fig. 9a, the slit q is linear and is located between one of the support areas B1 and the vibration area B2, and the vibration assembly 31 forms a cantilever structure. The top view of the micro-electromechanical unit 3 with the vibration assembly 31 shown in fig. 9a can be seen with reference to fig. 9b, where the cantilever structure is fixed at one end to the support structure 32 and free at the other end.

It should be appreciated that the support region B1 of the vibration assembly 31 may be secured to the top of the support structure 32, or may be secured in other securing manners. When the support region B1 of the vibration assembly 31 is fixed to the top of the support structure 32, the support region B1 may cover at least a portion of the top of the support structure 32.

In some embodiments, as shown in fig. 10, when the vibration assembly 31 has two opposite cantilever beam structures, a dome structure 33 may be provided at a slit q of the vibration assembly 31, and the dome structure 33 may be connected to the vibration assembly 31 through an elastic connection.

For a micro-electromechanical unit 3, when the width of the slit q is sufficiently small, for example, when the width of the slit q is smaller than 20 μm, an equivalent air sealing effect can be achieved by using thermal viscosity, and not only mechanical freedom of the cantilever structure can be achieved, but also the air sealing effect can be considered, so that the acoustic leakage of the vibration component 31 is <10dB below the frequency of 100 Hz. When the width of the slit Q is large, for example, when the width of the slit Q is larger than 20 μm, mechanical freedom of the cantilever structure can be realized, and the slit Q can also serve as a structure of the micro electromechanical unit 3 for communicating the acoustic cavity Q with an external space, thereby achieving the effect of sound transmission. The slit q in this case may be a slit f2 in fig. 3a or a slit f1 in fig. 3 a. In the embodiments described herein, slits q are identified as f when they are wide enough to allow sound waves to pass through, and can act as slits f of the sound guiding structure. When the slit q is sufficiently small in width to achieve a sealing effect of the vibration assembly 31, the slit is identified as q.

On the basis of the structure of the electroacoustic transducer 10 shown in fig. 2a, as shown in fig. 11a to 11c, the support structure 32 may further comprise an auxiliary support 322 for one of the microelectromechanical units 3, the auxiliary support 322 being arranged within the hollow structure of the annular support 321, the auxiliary support 322 also serving to support the vibrating assembly 31. The vibration assembly 31 between the auxiliary support 322 and the annular support 321 is provided with a slit q enabling the vibration assembly 31 between the auxiliary support 322 and the annular support 321 to form at least one cantilever beam structure.

In fig. 11a, the vibration assembly 31 between the auxiliary support 322 and the ring-shaped support 321 is formed with two cantilever beam structures. For the entire vibration assembly 31, a total of four cantilever beam structures are provided. In fig. 11b, the vibration assembly 31 between the auxiliary support 322 and the ring-shaped support 321 is formed with two cantilever beam structures. For the entire vibration assembly 31, a total of four cantilever beam structures are provided.

In fig. 11b, the vibration assembly 31 between the auxiliary support 322 and the left portion of the ring-shaped support 321 is formed with one cantilever beam structure, and the vibration assembly 31 between the auxiliary support 322 and the right portion of the ring-shaped support 321 is formed with two cantilever beam structures. For the entire vibration assembly 31, three cantilever beam structures are total.

In fig. 11b, the vibration assemblies 31 between the auxiliary supports 322 and the ring-shaped supports 321 are each formed with an cantilever beam structure. For the entire vibration assembly 31, there are a total of two cantilever beam structures.

It should be understood that the structure of the mems element 3 shown in fig. 11a to 11c can be regarded as a structure in which two mems elements 3 are arranged and combined in a horizontal direction, and the left and right mems elements 3 share the auxiliary support member 322.

Fig. 12 shows a cross-sectional structure of another electroacoustic transducer 10 according to an embodiment of the present application, in which two microelectromechanical units 3 are illustrated, two support structures 32 are each fixed to the substrate 1, and the two support structures 32 are sequentially disposed around from inside to outside. The support structures 32 are shown here in the configuration of the annular support 321 described above, wherein "disposed around" refers to between two adjacent support structures 32, the outer support structure 32 surrounds the inner support structure 32, and the shape of the support structure 32 is not limited to a circle, square, or other polygon. Between two adjacent micro-electromechanical units 3, the support structure 32 located at the outer side surrounds the support structure 32 located at the inner side. In order to align the two vibration assemblies 31 in the first direction Z, the height of the support structure 32 located at the outer side is higher than the height of the support structure 32 located at the inner side.

Based on the structure of the electroacoustic transducer 10 shown in fig. 12, fig. 13a to 13e show examples of the structure of the electroacoustic transducer 10.

As shown in fig. 13a and 13b, the micro-electromechanical unit 3a includes a vibration assembly 31a and a support structure 32a supporting the vibration assembly 31a, and the micro-electromechanical unit 3b includes a vibration assembly 31b and a support structure 32b supporting the vibration assembly 31 b. The support structures 32a and 32b are fixed to the substrate 1, and the support structures 32a and 32b support the vibration assemblies 31a and 31b in an arrangement along the first direction Z, the vibration assemblies 31a being located between the vibration assemblies 31b and the substrate 1. The vibration component 31a is disposed at the top end of the support structure 32a, and the acoustic cavity Q1 of the micro-electromechanical unit 3a is formed between the support structure 32a, the vibration component 31a and the substrate 1. The substrate 1 is provided with a sound-transmitting hole t which connects the acoustic cavity Q1 to an external space, and sound waves can be transmitted to the external space through the sound-transmitting hole t, which is a space of the substrate 1 on a side away from the vibration member 31 a. The support structure 32b, the substrate 1, the vibration assembly 31b and the micro-electromechanical unit 3a form an acoustic cavity Q2 of the micro-electromechanical unit 3b therebetween. A slit f2 is provided in the vibration module 31b, and the slit f2 connects the acoustic chamber Q2 to an external space, which is a space of the vibration module 31b on a side away from the vibration module 31a, through which the acoustic wave can be transmitted to the external space. The micro-electromechanical unit 3a is a full-frequency sound generating unit, and the micro-electromechanical unit 3b is a medium-high frequency sound generating unit. The vibration assembly 31a is provided with a slit q such that the vibration assembly 31a forms two cantilever beam structures as shown in fig. 13a or one cantilever beam structure as shown in fig. 13b, the width of the slit q being smaller than 20 μm to ensure that the vibration assembly 31a has an acoustic leakage <10dB below 100 Hz.

As shown in fig. 13c, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 13 a. The difference is that, with respect to the micro-electromechanical unit 3a, a slit f1 is provided on the vibration member 31a, the slit f1 connects the acoustic chamber Q1 to an external space, which is a space between the vibration member 31a and the vibration member 31b, through which the acoustic wave can be transmitted to the external space. The micro-electromechanical unit 3a and the micro-electromechanical unit 3b may be middle-high frequency sounding units, and may be loaded with the same middle-high frequency audio signals.

As shown in fig. 13d or 13e, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 13 a. The difference is that, for the micro-electromechanical unit 3b, a sound guiding hole d2 is provided on the support structure 32b, the sound guiding hole d2 connects the sound cavity Q2 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d2, and the external space is the accommodation cavity a. Wherein the vibration assembly 31a is provided with slits q such that the vibration assembly 31a forms two cantilever beam structures as shown in fig. 13d or one cantilever beam structure as shown in fig. 13e, and the vibration assembly 31b is provided with slits q such that the vibration assembly 31b forms two cantilever beam structures, the width of the slits q being smaller than 20 μm to ensure that the vibration assembly 31a and the vibration assembly 31b leak less than 10dB at frequencies of 100 Hz.

As shown in fig. 13f, the structure of the micro-electromechanical unit 3a and the micro-electromechanical unit 3b is similar to that in fig. 13 a. The difference is that, for the micro-electromechanical unit 3a, a sound guiding hole d1 is provided on the support structure 32a, the sound guiding hole d1 connects the sound cavity Q1 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d1, and the external space is the sound cavity Q2. The vibration assembly 31a is provided with slits q such that the vibration assembly 31a forms two cantilever beam structures, the width of the slits q being smaller than 20 μm to ensure that the vibration assembly 31a has an acoustic leakage <10dB below 100 Hz.

As shown in fig. 13g and 13h, the structure of the microelectromechanical unit 3a and the microelectromechanical unit 3b is similar to that in fig. 13 a. The difference is that, for the micro-electromechanical unit 3a, a sound guiding hole d1 is provided on the support structure 32a, the sound guiding hole d1 connects the sound cavity Q1 with an external space, and sound waves can be transmitted to the external space through the sound guiding hole d1, and the external space is the sound cavity Q2. For the micro electromechanical unit 3b, an acoustic port d2 is provided on the support structure 32b, the acoustic port d2 connects the acoustic cavity Q2 with an external space, and the acoustic wave can be transmitted to the external space through the acoustic port d2, and the external space is the accommodation cavity a. Wherein, the micro-electromechanical unit 3a and the micro-electromechanical unit 3b may be full-frequency sounding units, the vibration component 31a is provided with a slit q so that the vibration component 31a forms two cantilever beam structures, and the vibration component 31b is provided with a slit q so that the vibration component 31b forms two cantilever beam structures as shown in fig. 13g or one cantilever beam structure as shown in fig. 13h, and the width of the slit q is smaller than 20 μm to ensure that the sound leakage of the vibration component 31a and the vibration component 31b is less than 10dB below 100 Hz.

In the micro-electromechanical unit 3 provided in the embodiment of the present application, as shown in fig. 14a, the vibration component 31 includes a piezoelectric material layer 311, and a first electrode 312 and a second electrode 313 disposed on two surfaces of the piezoelectric material layer 311. The first electrode 312 and the second electrode 313 are electrically connected to the processing circuit on the substrate 1 through the bonding pads 11, respectively, and when the first electrode 312 and the second electrode 313 are energized, an electric field is formed between the first electrode 312 and the second electrode 313. The piezoelectric material layer 311 disposed between the first electrode 312 and the second electrode 313 is in an electric field, and generates a reverse piezoelectric effect to generate bending deformation. The deformation of the piezoelectric material layer 311 can drive the whole vibration assembly 31 to bend and deform, so as to push the air on two sides of the vibration assembly 31 to sound.

The piezoelectric material layer 311 may be provided with one or more layers. Specifically, the material of the piezoelectric material layer 311 may be one or a combination of more of lead zirconate titanate, aluminum nitride, scandium-doped aluminum nitride, and zinc oxide. The inverse piezoelectric effect is that when an electric field is applied in the polarization direction of dielectrics, the dielectrics generate mechanical deformation or mechanical pressure in a certain direction, and when the applied electric field is removed, the deformation or the stress is also eliminated.

In some embodiments, as shown in fig. 14b, the vibration assembly 31 may further include a substrate 314, the substrate 314 being fixed to the support structure 32, and the first electrode 312, the piezoelectric material layer 311, and the second electrode 313 being sequentially disposed on the substrate 314. The first electrode 312 may be in contact with the substrate 314, or the second electrode 313 may be in contact with the substrate 314. The substrate 314 may be a silicon-on-insulator (silicon on insulator, SOI) wafer, or a silicon wafer, in particular.

On the basis of the electroacoustic transducer 10 shown in fig. 3a, as shown in fig. 15a, when two micro-electromechanical units 3 are stacked in the first direction Z, the support structure 32b of the micro-electromechanical unit 3b located at the top may be fixed to the support structure 32a of the micro-electromechanical unit 3a located at the bottom, and the vibration assembly 31a may be perforated for the support structure 32b to pass through. Specifically, the buried groove m can be formed on the supporting structure 32a, the supporting structure 32b is fixed in the buried groove m by bonding or other modes, so that the mounting stability of the micro-electromechanical unit 3b at the top is improved, the dispensing and bonding in the packaging process are facilitated, the packaging process is simplified, and the packaging yield is improved.

The depth of the buried groove m can be set to be smaller than 100 μm, and the strength of the supporting structure is ensured while the buried groove packaging is realized.

As shown in fig. 15b, the vibration element 31a of the micro-electromechanical unit 3a is connected to the bonding pad 11a on the substrate 1 through the connection wire 4a, and the vibration element 31b of the micro-electromechanical unit 3b is connected to the bonding pad 11b on the substrate 1 through the connection wire 4 b. The connection wire 4b may be directly routed from the vibration component 31b to the pad 11b, or may be routed to the vibration component 31a and then to the pad 11b.

Further, as shown in fig. 15c, a conductive post 5 penetrating the support structure 32 may be provided, and the micro-electromechanical unit 3 is electrically connected to the substrate 1 by connecting the conductive post 5 to the pad 11 on the substrate 1. Referring specifically to fig. 15d, for the micro-electromechanical unit 3a, conductive posts 5a penetrating the support structure 32a are provided, and both ends of the conductive posts 5a are connected to the vibration assembly 31a and the bonding pads 11a on the substrate 1, respectively, so as to electrically connect the micro-electromechanical unit 3a and the substrate 1. For the micro-electromechanical unit 3b, a conductive post 5b penetrating through the supporting structure 32a and the supporting structure 32b is provided, and two ends of the conductive post 5b are respectively connected with the vibration component 31b and the bonding pad 11b on the substrate 1, so as to realize the electrical connection of the micro-electromechanical unit 3b and the substrate 1. The conductive pillars 5b are located partially within the support structure 32a and partially within the support structure 32 b. By connecting the vibration assembly 31 and the substrate 1 via the conductive posts 5, external wiring can be omitted, thereby reducing the package size of the electroacoustic transducer 10 in a direction parallel to the substrate 1, which is advantageous for further miniaturization of the device. The direction parallel to the substrate 1 refers to a direction parallel to the second direction X and the third direction Y, that is, a direction perpendicular to the first direction Z.

Based on the electroacoustic transducer 10 in the above embodiment, the embodiment of the present application also provides an electronic device. As shown in fig. 16a and 17a, the electronic device is exemplified by a headset 100. The earphone 100 includes a housing 20 and the electroacoustic transducer 10 provided in the foregoing embodiments, where the electroacoustic transducer 10 may be a side-emitting structure as a sound generating unit of the earphone 100. In fig. 16a and 17a, the housing 20 comprises in particular an earplug 201 and a handle 202, the earplug 201 having a mouthpiece n, and the electroacoustic transducer 10 being located within the earplug 201 at the mouthpiece n such that the sound outlet k on the housing 2 corresponds to the mouthpiece n. The earphone 100 also has a signal input (not shown here) capable of applying a first audio signal to the electroacoustic transducer 10 so that the electroacoustic transducer 10 performs a function such as music playing or talking under the action of the first audio signal.

Among them, the electroacoustic transducer 10 has higher sensitivity in the middle-high frequency band, and can improve the sound quality of the earphone 100. The stacking of the mems elements 3 may achieve a smaller size of the device, and is more suitable for being placed at the sound outlet n of the earphone 100, so that the sound generating unit of the earphone 100 is closer to the eardrum of the consumer, and further, the sound acquisition sensitivity of the consumer in use can be improved, which is equivalent to improving the high-frequency acoustic sensitivity of the earphone 100.

Fig. 16b shows a cross-sectional structure of a portion of the earplug 201 shown in fig. 16a, the earplug 201 having a receiving space, the receiving space being in communication with the mouthpiece n. The electroacoustic transducer 10 is disposed in the accommodation space, the sound outlet k of the electroacoustic transducer 10 is located at the side of the housing 2, and the sound outlet k of the electroacoustic transducer 10 is directed toward the sound outlet n. The electroacoustic transducer 10 receives the first audio signal, converts the first audio signal into an acoustic signal, and then emits sound from the sound outlet k to be emitted through the sound outlet n.

With further reference to the enlarged cross-sectional structure of the electroacoustic transducer 10 in the earplug 201 shown in fig. 16c, the electroacoustic transducer 10 comprises a substrate 1, a housing 2 and two stacked micro-electromechanical units 3, the two micro-electromechanical units 3 being arranged in a receiving cavity a formed by the substrate 1 and the housing 2. The acoustic cavity Q1 formed between the micro-electromechanical unit 3a located at the bottom and the substrate 1 communicates with the external space through the acoustic transmission hole t on the substrate 1, and the acoustic cavity Q2 formed between the micro-electromechanical unit 3b located at the top and the micro-electromechanical unit 3a located at the bottom communicates with the external space through the slit f2 located on the micro-electromechanical unit 3 a. The receiving chamber a communicates with the mouthpiece n through the mouthpiece k on the side of the housing 2. The sound emitted by the two micro-electromechanical units 3 can be transmitted out through the gap f2, the sound outlet k and the sound outlet mouth n.

In an earphone 100 of the example shown in fig. 17a, the electroacoustic transducer 10 may be arranged in the receiving space of the earplug 201 by way of example of a cross-sectional structure of a part of the earplug 201 in fig. 17 b. The sound outlet k of the electroacoustic transducer 10 is located on the top surface of the housing 2, and the sound outlet k faces the sound outlet mouth n. The electroacoustic transducer 10 receives the electric signal, converts the electric signal into an acoustic signal, and then emits sound from the sound outlet k to be emitted through the sound outlet nozzle n.

In the structure of the earphone 100 illustrated in fig. 17b, the earphone 100 further includes a moving coil speaker 30, and the moving coil speaker 30 is also connected to the signal input end, so as to receive the second audio signal sent by the signal input end and implement a music playing or talking function. The moving-coil speaker 30 and the electroacoustic transducer 10 simultaneously serve as generating units of the earphone 100, and can convert an audio signal into a sound signal which is output from a signal input terminal. Since the electroacoustic transducer 10 has better performance in the middle-high frequency band of the audio signal, the frequency of the first audio signal may be greater than that of the second audio signal, thereby improving the sensitivity of the earphone 100 in the middle-high frequency band and improving the sound quality of the earphone 100. Through experiments, the high-frequency bandwidth of the earphone 100 can be expanded to 20kHz, and such an audio bandwidth can enable the earphone 100 to obtain high-fidelity sound quality.

With further reference to the enlarged cross-sectional structure of the electroacoustic transducer 10 in the earplug 201 shown in fig. 17c, the electroacoustic transducer 10 comprises a substrate 1, a housing 2 and two stacked micro-electromechanical units 3, the two micro-electromechanical units 3 being arranged in a receiving cavity a formed by the substrate 1 and the housing 2. The acoustic cavity Q1 formed between the micro-electromechanical unit 3a located at the bottom and the substrate 1 communicates with the external space through the acoustic transmission hole t on the substrate 1, and the acoustic cavity Q2 formed between the micro-electromechanical unit 3b located at the top and the micro-electromechanical unit 3a located at the bottom communicates with the external space through the slit f2 located on the micro-electromechanical unit 3 a. The receiving chamber a communicates with the mouthpiece n through the mouthpiece k on the top surface of the housing 2. The sound emitted by the two micro-electromechanical units 3 can be transmitted out through the gap f2, the sound outlet k and the sound outlet mouth n.

Based on the structure of the electroacoustic transducer 10 provided in the above embodiment, the embodiment of the present application also provides a manufacturing method of the electroacoustic transducer, and the manufacturing method may be used to manufacture the electroacoustic transducer 10. As shown in fig. 18, the preparation method may include the steps of:

s1: a substrate is provided, and a processing circuit is disposed on the substrate.

When the mechanism of the electroacoustic transducer 10 is as shown in fig. 3a, the structure of the substrate 1 may be as shown with reference to fig. 19 a. When the mechanism of the electroacoustic transducer 10 is as shown in fig. 3b, the structure of the substrate 1 may be as shown with reference to fig. 19 b.

S2: at least two micro electromechanical units are arranged on the substrate; each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, and the vibration components respectively included in at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate; each vibration component is electrically connected with the processing circuit respectively; in each micro-electromechanical unit, an acoustic cavity of the micro-electromechanical unit is formed on the side, facing the substrate, of the vibration assembly, and the acoustic cavity is communicated with the external space for passing acoustic waves.

The structure of at least two micro-electromechanical units 3 may be as shown in fig. 3a to 3g, wherein two micro-electromechanical units 3 are stacked along a first direction Z. The structure of at least two micro-electromechanical units 3 may be as shown in fig. 13a to 13h, where the two micro-electromechanical units 3 are sleeved in sequence from inside to outside.

When at least two micro-electromechanical units 3 may be stacked along the first direction Z as shown in fig. 3a to 3g, or may be sleeved around as shown in fig. 13a to 13h, so long as each vibration component 31 is sequentially arranged along the first direction Z.

Illustratively, the at least two micro-electromechanical units 3 include a micro-electromechanical unit 3a and a micro-electromechanical unit 3b, the micro-electromechanical unit 3a and the micro-electromechanical unit 3b are stacked along the first direction Z, the micro-electromechanical unit 3a is disposed on the substrate 1, and the micro-electromechanical unit 3b is disposed on a side of the micro-electromechanical unit 3a facing away from the substrate 1. The micro-electromechanical unit 3a includes a vibration assembly 31a and a support structure 32a for supporting the vibration assembly 31a, the support structure 32a being fixed to the substrate 1. The micro-electromechanical unit 3b includes a vibration assembly 31b and a support structure 32b for supporting the vibration assembly 31b, the support structure 32b being fixed to the support structure 32a. In the above step S2, as shown in fig. 20, the step of disposing at least two micro-electromechanical units 3 on the substrate 1 includes the steps of:

S21: the support structure of one of the micro-electromechanical units is fixed to the substrate.

Taking the structure of the substrate 1 shown in fig. 19a as an example, the support structure 32a is fixed to the substrate 1, resulting in the structure shown in fig. 21a or fig. 22 a. The vibrating assembly 31a, the support structure 32a and the substrate 1 form an acoustic cavity Q1 of the micro-electromechanical unit 3 a. A slit q is also provided in the vibration module 31a, and the slit q forms the vibration module 31a into two cantilever beam structures. When the support structure 32a is adhesively secured to the substrate 1 by means of the adhesive 7, a structure as shown in fig. 21b or fig. 22b is obtained.

When the vibration assembly 31a and the vibration assembly 31b are electrically connected to the pads 11 on the substrate 1 by the connection wires 4, respectively, as shown in fig. 21a and 21b, the orthographic projection of at least part of the pads 11 on the substrate 1 is located outside the orthographic projection range of the support structure 32a on the substrate 1.

When the vibration component 31a is electrically connected to the pads 11 on the substrate 1 through the conductive posts 5a, the support structure 32a is provided with the conductive posts 5a penetrating the support structure 32a in the first direction Z and the first portions 51b of the conductive posts 5b when the vibration component 31b is electrically connected to the pads 11 on the substrate 1 through the conductive posts 5 b. As shown in fig. 22a and 22b, the orthographic projection of the pad 11 on the substrate 1 is within the orthographic projection range of the support structure 32a on the substrate 1. The pads 11a on the substrate 1 are correspondingly connected to the conductive posts 5a, and the pads 11b are correspondingly connected to the first portions 51b of the conductive posts 5 b. In fig. 22b, in order to avoid the conductive pillars 5, there is no overlapping area between the orthographic projection of the adhesive 7 on the substrate 1 and the orthographic projection of the pad 11 on the substrate 1.

S22: and a buried groove is arranged on one side of the micro-electromechanical unit, which is away from the substrate.

Taking the structure shown in fig. 21b as an example, the buried groove m provided on the side of the micro-electromechanical unit 3a away from the substrate 1 penetrates the vibration element 31a and extends into the support structure 32a, and the structure shown in fig. 23 can be obtained.

Taking the structure shown in fig. 22b as an example, a buried groove m provided on a side of the micro-electromechanical unit 3a away from the substrate 1 penetrates the vibration assembly 31a and extends into the support structure 32a, and the buried groove m corresponds to the first portion 51b of the conductive post 5b, so that the structure shown in fig. 24 can be obtained.

S23: the support structure of the other microelectromechanical unit is fixed into the buried trench.

As shown in fig. 25 and 26, after the support structure 32b of the micro-electromechanical unit 3b is fixed into the buried groove m, the micro-electromechanical unit 3b may be disposed in a stacked manner to a side of the micro-electromechanical unit 3a facing away from the substrate 1. An acoustic cavity Q2 of the micro-electromechanical unit 3b is formed between the micro-electromechanical unit 3b and the micro-electromechanical unit 3 a. The vibration component 31b of the micro-electromechanical unit 3b is provided with a gap f2, and the gap f2 communicates the acoustic cavity Q2 with the external space.

In fig. 26, the supporting structure 32b is provided with a second portion 52b penetrating the conductive post 5b of the supporting structure 32b in the first direction Z, and the first portion 51b of the conductive post 5b is correspondingly connected with the second portion 52b to form the conductive post 5b, so as to connect the vibration component 31b with the pad 11 b.

Wherein, after step S22 is performed and before step S23 is performed, as shown in fig. 27, the preparation method may further include the steps of:

s22': and coating auxiliary adhesive in the buried groove.

In some embodiments, on the basis of the structure shown in fig. 23, an auxiliary adhesive 8 may be applied in the buried groove m as shown in fig. 28a to more firmly fix the support structure 32b into the buried groove m. The auxiliary adhesive 8 here serves to strengthen the fixation and may in particular comprise an adhesive. After fixing the support structure 32b of the micro-electromechanical unit 3b to the buried trench m, the structure shown in fig. 28b can be obtained.

After the micro-electromechanical unit 3b and the micro-electromechanical unit 3b are combined, as shown in fig. 29a and 29b, the vibration component 31a from the micro-electromechanical unit 3a is routed to the pads 11 of the substrate 1 through the connection wires 4a to be connected to the processing circuit. The vibrating element 31b from the micro-electromechanical unit 3b is routed to the pads 11 of the substrate 1 by connecting wires 4b for connection to a processing circuit. The second connection wire 4b may be directly routed to the substrate 1 as shown in fig. 29a, or may be routed to the vibration component 31a first and then to the substrate 1 as shown in fig. 29 b.

In other embodiments, on the structural substrate shown in fig. 24, an auxiliary adhesive 8 may be applied within the buried groove m as shown in fig. 30 to more firmly fix the support structure 32b into the buried groove m. The auxiliary adhesive 8 not only plays a role of reinforcing fixation, but also can realize connection of the first portion 51b and the second portion 52b of the conductive post 5b, and the auxiliary adhesive 8 can comprise an adhesive and a conductive adhesive. After fixing the support structure 32b of the micro-electromechanical unit 3b to the buried trench m, the structure shown in fig. 31 can be obtained.

After the assembly of the microelectromechanical unit 3 is completed, the encapsulation of the housing 2 is performed.

The arrangement of the buried groove m facilitates the superposition of two adjacent micro-electromechanical units 3 along the first direction Z, is beneficial to the positioning and fixing of the micro-electromechanical units 3 positioned at the top in the packaging process, simplifies the packaging process and improves the packaging yield.

S3: fixing the housing to the substrate to encapsulate the at least two microelectromechanical units and the processing circuitry within a receiving cavity formed between the housing and the substrate; the housing is provided with an acoustic port in communication with the receiving chamber.

The structure after fixing the housing 2 to the substrate 1 can be referred to as shown in fig. 32 on the basis of the structure shown in fig. 29 a. The structure after fixing the housing 2 to the substrate 1 can be referred to as shown in fig. 33 on the basis of the structure shown in fig. 31. A receiving cavity a is formed between the housing 2 and the substrate 1, and two micro-electromechanical units 3 are located in the receiving cavity a. The casing 2 is provided with a sound outlet k. The sounds emitted by the micro-electromechanical unit 3b and the first micro-electromechanical unit 3b can be transmitted out through the sound emitting hole k. Wherein in fig. 32 the sound outlet k is located at the top of the housing 2 and in fig. 33 the sound outlet k is located at the top of the housing 2.

In some embodiments, as shown in fig. 34, after the housing 2 is fixed to the substrate 1 in step S3, the manufacturing method further includes the steps of:

S4: a mesh cloth covering the sound outlet is arranged.

In addition to the structure shown in fig. 32, a mesh cloth 9 covering the sound outlet k is provided at the sound outlet k, and the structure shown in fig. 35 can be obtained. In addition to the structure shown in fig. 33, a mesh cloth 9 covering the sound outlet k is provided at the sound outlet k, and the structure shown in fig. 36 can be obtained. The base plate 1 is also provided with a sound transmission hole t, and a mesh cloth 9 covering the sound transmission hole t can be arranged at the sound transmission hole t. The mesh cloth 9 can play a role in dust prevention and protection.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes or substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An electroacoustic transducer, comprising:

a substrate on which a processing circuit is provided;

a housing fixed on the substrate, wherein a containing cavity for containing the processing circuit is formed between the housing and the substrate, and the housing is provided with an acoustic hole communicated with the containing cavity;

The at least two micro-electromechanical units are arranged in the accommodating cavity, each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, the vibration components respectively included in the at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate; each of the vibration assemblies is electrically connected with the processing circuit; the vibration component in each micro-electromechanical unit is provided with an acoustic cavity of the micro-electromechanical unit on the side facing the substrate, and the acoustic cavity is communicated with an external space for passing acoustic waves.

2. The electroacoustic transducer of claim 1 wherein said at least two microelectromechanical units comprise a first microelectromechanical unit and at least one second microelectromechanical unit, said first microelectromechanical unit comprising said vibration assembly located between said vibration assembly and said substrate comprised by said at least one second microelectromechanical unit, respectively;

for the first micro-electromechanical unit, the first micro-electromechanical unit is provided with an acoustic guiding structure for communicating the acoustic cavity with the external space; or, the base plate is provided with an acoustic hole so as to communicate the acoustic cavity with the external space;

For any one of the second micro-electromechanical units, the second micro-electromechanical unit is provided with an acoustic guiding structure to communicate the acoustic cavity with the external space.

3. The electroacoustic transducer of claim 2 wherein said sound guiding structure is a slit extending through said vibration assembly, said slit having a width of 10 μm or more.

4. The electroacoustic transducer of claim 2 wherein said sound guiding structure is a sound guiding hole extending through said support structure, said sound guiding hole having a cross-sectional area of 0.01mm or more ² 。

5. The electroacoustic transducer of any of claims 1 to 4 wherein each of said vibration assemblies is provided with a slit to form an cantilever structure.

6. The electroacoustic transducer of claim 5 wherein said slit is U-shaped or i-shaped in shape.

7. The electroacoustic transducer of any of claims 1 to 6 wherein said support structure comprises an annular support supported at an edge of said vibration assembly; the annular support is located on a peripheral side of an acoustic cavity of the microelectromechanical unit, and the vibration assembly is located on a top side of the acoustic cavity of the microelectromechanical unit.

8. The electroacoustic transducer of claim 7 wherein at least two of said annular supports are stacked one above the other in said first direction.

9. The electroacoustic transducer according to claim 8 wherein a buried groove is provided on a side of the annular support at the bottom facing away from said base plate, said annular support at the top being fixed in said buried groove.

10. The electroacoustic transducer of claim 9 wherein an auxiliary adhesive is disposed in said buried channel.

11. The electroacoustic transducer of claim 10 wherein said auxiliary adhesive comprises an adhesive when each of said vibration assemblies is connected to said processing circuitry by a connecting wire, respectively.

12. The electroacoustic transducer of claim 10 wherein said auxiliary adhesive comprises an adhesive and a conductive paste when each of said vibration assemblies is connected to said processing circuitry by a conductive post extending through said support structure, respectively.

13. The electroacoustic transducer according to any of claims 10 to 12 wherein the depth of said buried groove is less than 100 μm.

14. The electroacoustic transducer of claim 7 wherein at least two of said annular supports are disposed sequentially around from inside to outside;

Between any two adjacent annular supports, the height of the annular support on the outer side is greater than the height of the annular support on the inner side.

15. The electroacoustic transducer of any of claims 1 to 14 wherein said vibration assembly comprises a substrate and a first electrode, a layer of piezoelectric material and a second electrode stacked in sequence on said substrate; the substrate is fixed to the support structure;

the first electrode and the second electrode are electrically connected with the processing circuit, respectively.

16. The electroacoustic transducer of claim 15 wherein the material of said piezoelectric material layer comprises one or a combination of at least two of lead zirconate titanate, aluminum nitride, scandium doped aluminum nitride, zinc oxide.

17. The electroacoustic transducer according to any of claims 1 to 16 wherein a mesh is provided at the sound outlet opening covering the sound outlet opening.

18. An electronic device, comprising: a housing, a signal input, and an electroacoustic transducer as claimed in any of claims 1-17;

the shell is provided with a sound outlet nozzle, and the electroacoustic transducer is arranged in the shell and is positioned at the sound outlet nozzle; the signal input is electrically connected with the substrate to apply a first audio signal to the vibration assembly through the substrate.

19. The electronic device of claim 18, further comprising a moving coil speaker disposed within the housing, the signal input further coupled to the moving coil speaker to apply a second audio signal to the moving coil speaker;

the frequency of the first audio signal is higher than the frequency of the second audio signal.

20. A method of manufacturing an electroacoustic transducer, comprising:

providing a substrate, and arranging a processing circuit on the substrate;

at least two micro-electromechanical units are arranged on the substrate; each micro-electromechanical unit comprises a vibration component and a supporting structure for supporting the vibration component, wherein the vibration components respectively included in the at least two micro-electromechanical units are sequentially arranged along a first direction, and the first direction is perpendicular to the substrate; each vibration component is electrically connected with the processing circuit; in each micro-electromechanical unit, an acoustic cavity of the micro-electromechanical unit is formed on one side, facing the substrate, of the vibration assembly, and the acoustic cavity is communicated with an external space for passing acoustic waves;

fixing a housing to the substrate to encapsulate the at least two microelectromechanical units and the processing circuitry within a receiving cavity formed between the housing and the substrate; the housing is provided with an acoustic port in communication with the receiving chamber.

21. The method of manufacturing of claim 20, wherein the at least two microelectromechanical units comprise two microelectromechanical units stacked along the first direction;

the disposing at least two microelectromechanical units on the substrate arrangement includes:

securing the support structure of one of the microelectromechanical units to the substrate;

the support structure of the other microelectromechanical unit is secured within the buried trench.

22. The method of manufacturing of claim 21, wherein the manufacturing method further comprises, after the step of disposing a buried trench in a side of the microelectromechanical unit facing away from the substrate, before the step of fixing the support structure of another microelectromechanical unit into the buried trench:

and coating auxiliary adhesive in the buried groove.

23. The method of any one of claims 20-22, wherein after the securing of the housing to the substrate, the method further comprises:

and arranging mesh cloth covering the sound outlet holes.