WO2022100551A1 - Mems piezoelectric microspeaker, microspeaker unit, and electronic device - Google Patents

Abstract

The present invention provides an MEMS piezoelectric microspeaker, a microspeaker unit, and an electronic device. The MEMS piezoelectric microspeaker comprises: an MEMS piezoelectric actuator for generating a speaker sound wave; and a miniature microphone integrated in the MEMS piezoelectric microspeaker and configured to generate a sound pressure signal on the basis of the speaker sound wave to adjust the sound output performance of the MEMS piezoelectric actuator. A sound pressure measurement portion of the miniature microphone is located outside the MEMS piezoelectric actuator and is separated from the MEMS piezoelectric actuator.

Description

MEMS piezoelectric micro-speaker, micro-speaker unit and electronic equipment

This disclosure claims the priority of a Chinese patent application with the application number 202011255318.6 and the application title "MEMS Piezoelectric Microspeaker, Microspeaker Unit and Electronic Equipment", which was filed with the China Patent Office on November 11, 2020, the entire contents of which are by reference Incorporated in this disclosure.

technical field

The present disclosure relates to the technical field of MEMS piezoelectric micro-speakers, and more particularly, to a MEMS piezoelectric micro-speaker, a micro-speaker unit and an electronic device.

Background technique

A microspeaker is a tiny device that converts electrical signals into sound waves. Microspeakers can be fabricated using MEMS technology. Micro speakers can be widely used in various electronic devices, such as in-ear headphones, headphones, mobile phones, tablet computers, etc.

The microspeaker includes an actuator. Actuators can be implemented piezoelectrically through MEMS technology to generate loudspeaker sound waves. For example, on a MEMS silicon wafer, the actuator is implemented in the form of piezoelectric ceramic PZT. The MEMS piezoelectric actuator can be a diaphragm, a cantilever, or the like.

For example, US Pat. No. 8,811,636 B2 discloses a microspeaker with piezoelectric, metallic and dielectric diaphragms. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 8,014,547 B2 discloses a piezoelectric speaker and a method of manufacturing the same. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 8,275,158 B2 discloses a piezoelectric microspeaker. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 8,401,220 B2 discloses a piezoelectric microspeaker with curved leads and a method of making the same. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 8,520,868 B2 discloses a piezoelectric microspeaker with curved leads and a method of making the same. This patent is incorporated herein by reference in its entirety.

For example, U.S. Patent No. 8,335,329 B2 discloses a piezoelectric microspeaker and a method of making the same. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 8,114,697 B2 discloses a piezoelectric microphone, a speaker, a microphone-speaker integrated device, and a method of manufacturing the same, wherein the microphone and speaker can be placed separately on the same silicon substrate. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 10,284,986 B2 discloses a piezoelectric speaker and a method of making the same. This patent is incorporated herein by reference in its entirety.

For example, US patent application US 2018/0317017 A1 discloses a piezoelectric speaker and a method of manufacturing the same. This patent is incorporated herein by reference in its entirety.

For example, US patent application US 2018/0317017 A1 discloses a piezoelectric speaker and a method of manufacturing the same. This patent is incorporated herein by reference in its entirety.

For example, US Pat. No. 9,980,051 B2 discloses a MEMS speaker with an actuator structure and a diaphragm spaced apart. This patent is incorporated herein by reference in its entirety.

For example, Chinese patent application CN106488366 A1 discloses a MEMS speaker with a position sensor. This patent is incorporated herein by reference in its entirety.

For example, Chinese patent application CN107925834 A discloses a MEMS speaker with a closed control system. This patent is incorporated herein by reference in its entirety.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure provide new technical solutions for MEMS piezoelectric microspeakers.

According to a first aspect of the present disclosure, there is provided a micro-speaker, comprising: a MEMS piezoelectric actuator for generating speaker sound waves; and a micro-microphone integrated inside the MEMS piezoelectric micro-speaker for generating sound pressure signals based on the speaker sound waves to It is used to adjust the sound output performance of the MEMS piezoelectric actuator, wherein the sound pressure detection part of the micro-microphone is located outside the MEMS piezoelectric actuator and is separated from the MEMS piezoelectric actuator.

According to a second aspect of the present disclosure, there is provided a micro-speaker unit including a housing, a MEMS piezoelectric micro-speaker and a micro-speaker driver chip according to an embodiment, wherein the MEMS piezoelectric micro-speaker and the micro-speaker driver chip are provided in the housing.

According to a third aspect of the present disclosure, there is provided an electronic device including a micro speaker unit according to an embodiment.

In various embodiments, the sound output performance of the MEMS piezoelectric micro-speaker can be adjusted through the sound signal of the micro-microphone, thereby improving the MEMS piezoelectric micro-speaker.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not limiting of the embodiments of the present disclosure.

Furthermore, any of the embodiments of the present disclosure is not required to achieve all of the effects described above.

Other features and advantages of embodiments of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings.

Description of drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are just some of the embodiments described in the embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings can also be obtained according to these drawings.

FIG. 1 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to one embodiment.

FIG. 2 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

FIG. 3 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

FIG. 4 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

FIG. 5 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

Figure 6 shows a schematic block diagram of a MEMS piezoelectric microspeaker unit according to another embodiment.

Figure 7 shows a schematic diagram of an electronic device according to another embodiment.

Detailed ways

Various exemplary embodiments will now be described in detail with reference to the accompanying drawings.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses in any way.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further discussion in subsequent figures.

In the following, various embodiments and examples of the present disclosure are described with reference to the accompanying drawings.

Here, the MEMS piezoelectric micro-speaker includes: a MEMS piezoelectric actuator and a micro-microphone integrated inside the MEMS piezoelectric micro-speaker. MEMS piezoelectric actuators generate speaker sound waves. MEMS piezoelectric actuators are components that generate acoustic vibrations. Micro microphones generate sound pressure signals based on speaker sound waves, which are used to adjust the sound output performance of MEMS piezoelectric actuators. The sound pressure detection part of the micro microphone is located outside the MEMS piezoelectric actuator and is separated from the MEMS piezoelectric actuator.

At present, due to the small size of the MEMS piezoelectric microspeaker, it is difficult to improve the acoustic performance of the MEMS piezoelectric microspeaker, or higher costs are required to improve the acoustic performance of the MEMS piezoelectric microspeaker. In addition, the reliability of MEMS piezoelectric microspeakers also needs to be considered when adding structures to improve performance.

In the embodiments herein, the sound output performance of the MEMS piezoelectric micro-speaker can be adjusted through the sound pressure signal obtained by the micro-microphone, thereby improving the MEMS piezoelectric micro-speaker. The feedback adjustment of the MEMS piezoelectric micro-speaker using the sound pressure signal can improve the performance of the MEMS piezoelectric micro-speaker at a low cost. The technology of micro-microphones is relatively mature and has a high degree of integration. Through this design, the existing mature technology can be fully utilized to realize the performance improvement of the MEMS piezoelectric microspeaker. In addition, since the technology of the micro-microphone is relatively mature, it is also beneficial to improve the stability of the performance improvement of the MEMS piezoelectric micro-speaker.

Here, the use of die-level micro-microphones, rather than microphone modules, can improve the integration of MEMS piezoelectric micro-speakers. In addition, the packaged micro-microphone module will affect the MEMS piezoelectric actuator, and the micro-microphone can be combined with the MEMS piezoelectric micro-speaker to avoid or reduce the impact on the MEMS piezoelectric micro-speaker. In addition, the micro-microphone is also manufactured by MEMS technology, therefore, the micro-microphone and MEMS piezoelectric micro-speaker are also suitable to be integrated together.

The sound pressure signal can directly reflect the current state of the MEMS piezoelectric micro-speaker, so the MEMS piezoelectric micro-speaker can be adjusted more accurately.

In addition, the micro-microphone integrated inside the MEMS piezoelectric micro-speaker can reflect the direct state of the MEMS piezoelectric micro-speaker without the influence of the intermediate sound path.

Since the micro-microphone is integrated inside the MEMS piezoelectric micro-speaker, the integration of the MEMS piezoelectric micro-speaker can be improved, and it is not necessary to set other detection devices outside the MEMS piezoelectric micro-speaker to detect the output performance of the speaker for adjustment. .

In this embodiment, since the sound pressure detection part of the micro-microphone is located outside the MEMS piezoelectric actuator and is separated from the MEMS piezoelectric actuator, the detection of the micro-microphone will not affect the sound-emitting part of the MEMS piezoelectric micro-speaker The effect is that there is no need to provide a specially designed structure on the MEMS piezoelectric actuator of the MEMS piezoelectric micro-speaker for the sound pressure detection part. On the one hand, this leaves more design freedom for the design of the MEMS piezoelectric actuator of the microspeaker. Designers can design various forms of MEMS piezoelectric actuators as needed. On the other hand, the operation of the sound pressure detection portion of the micro-microphone does not affect the operation of the MEMS piezoelectric actuator, thereby introducing no disturbance to the MEMS piezoelectric micro-speaker, or less disturbance to the micro-speaker. This can also improve the detection accuracy of the detection section.

Various embodiments of the MEMS piezoelectric microspeaker are described below with reference to FIGS. 1-5.

FIG. 1 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to one embodiment.

As shown in FIG. 1 , the MEMS piezoelectric microspeaker includes a top cover 11 and a substrate 18 . Top cover 11 and substrate 18 surround the internal components of the microspeaker. Substrate 18 may be a PCB substrate. A sound hole 12 is provided in the top cover 11 . In Figure 1, the acoustic holes 12 are arranged as front-firing acoustic holes. However, the sound hole 12 may also be a side-firing sound hole, that is, arranged on the side surface of the top cover 11 .

A MEMS piezoelectric actuator is arranged inside the MEMS piezoelectric micro-speaker. The MEMS piezoelectric actuator includes a substrate 17 , a piezoelectric ceramic actuation plate 15 , an upper electrode 14 and a lower electrode 16 . The substrate 17 divides the MEMS piezoelectric microspeaker into a front cavity 13 and a rear cavity 19 . The piezoelectric ceramic actuating plate 15 is provided on the substrate 17 . As shown in FIG. 1 , the upper electrode 14 is provided above the piezoelectric ceramic actuating plate 15 , and the lower electrode 16 is provided below the piezoelectric ceramic actuating plate 15 . The upper electrode 14 and the lower electrode 16 are connected to wirings in the substrate 18 and thus connected to the corresponding driving chips.

In this embodiment, the vibrating component of the micro-microphone is a MEMS piezoelectric actuator. The capacitive detection electrode 21 of the micro-microphone is located on the substrate 18 opposite the MEMS piezoelectric actuator in the back cavity 19 of the MEMS piezoelectric micro-speaker. The detection electrode 21 is a MEMS piezoelectric actuator and is separate from the MEMS piezoelectric actuator. The detection electrodes 21 are connected to the microphone-specific integrated circuit ASIC of the micro-microphone, for example, by wiring in the substrate 18 .

The microphone application specific integrated circuit ASIC is not shown in FIG. 1 . The microphone-specific integrated circuit ASIC can be set together with the driving chip of the MEMS piezoelectric micro-speaker, or can be set separately.

Here, the MEMS piezoelectric actuator can be used as the back plate of the micro-microphone. The detection electrode 21 and the back plate form a capacitance for detecting sound signals. The sound signal detected by the micro microphone is output by the detection electrode 21 . Since the detection electrode 21 is located on the relatively fixed substrate 18, detection noise, eg, noise generated by vibration itself, and noise generated in the metal electrode and its leads due to vibration can be reduced. In addition, this arrangement can also reduce the mechanical loss of the operation of the detection electrode 21 due to vibration, thereby improving the stability of the device. In this design, only the ground reference for the micro-microphone needs to be formed in the MEMS piezoelectric actuator. This structure can simplify the design and fabrication process of MEMS piezoelectric microspeakers. Furthermore, the processing of the detection electrode 21 does not affect the MEMS piezoelectric actuator.

The MEMS piezoelectric actuator may or may not include the substrate 17 . The substrate 17 may be a metal substrate. The piezoelectric ceramic actuating plate 15 is provided on the metal substrate 17 . The influence of external noise (eg, electromagnetic noise) on the detection electrode 21 can be shielded or mitigated by the metal substrate 17 , thereby improving the detection performance of the micro-microphone.

As shown in FIG. 1 , the substrate 18 also includes an air outlet 20 . The air outlet 20 communicates the rear cavity 19 with the outside. In this case, the air pressure in the rear chamber 19 may be the atmospheric pressure of air. The air pressure in the front chamber 13 is also the atmospheric pressure of air. In this way, the pressure on both sides of the MEMS piezoelectric actuator is balanced.

FIG. 2 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

In FIG. 2 , the capacitance detection electrode 22 is connected to the microphone ASIC 23 . Microphone ASIC 23 is disposed in back cavity 19 and on substrate 18 .

FIG. 3 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

In FIG. 3 , the capacitance detection electrodes 22 are connected to the microphone ASIC 24 . Microphone application specific integrated circuits 24 are embedded in substrate 18 . In this way, it is possible to provide protection for the microphone ASIC 24, avoiding or reducing external mechanical shocks or electromagnetic influences to which the microphone ASIC 24 is subjected.

4 and 5 illustrate schematic structural diagrams of MEMS piezoelectric microspeakers according to further embodiments. In the various embodiments of Figures 4 and 5, the micro-microphone includes a micro-electromechanical microphone die and a microphone-specific integrated circuit ASIC. Since the micro-microphone includes an independent micro-electro-mechanical microphone die, the reliance on the MEMS piezoelectric micro-speaker structure can be further reduced, thereby providing a higher degree of freedom in design.

In Figure 4, the microelectromechanical microphone die 25 is located in the back cavity 19 of the MEMS piezoelectric microspeaker. The MEMS microphone die 25 is connected to a microphone application specific integrated circuit ASIC 26 . In this case, the micro-microphone can be protected to avoid or reduce the influence of external airflow and electromagnetics on the micro-microphone.

As previously mentioned, the substrate 17 may be a metal substrate. Thereby, better electromagnetic shielding is provided for the micro-microphone, thereby further avoiding the influence of external factors on the detection with the micro-microphone.

FIG. 5 shows a schematic structural diagram of a MEMS piezoelectric microspeaker according to another embodiment.

The microelectromechanical microphone die 27 is located in the front cavity 13 of the MEMS piezoelectric microspeaker and is horizontally separated from the MEMS piezoelectric actuator. The MEMS microphone die 27 is connected to a microphone application specific integrated circuit ASIC 28 .

Since the microelectromechanical microphone die 27 is horizontally separated from the MEMS piezoelectric actuator, mutual influence between them can be avoided.

In Figures 4 and 5, the microphone ASICs 26, 28 may be located above the substrate 18; they may also be located within the substrate 18 as previously described, thereby providing protection for the microphone ASICs.

Figure 6 shows a schematic block diagram of a micro speaker unit according to another embodiment.

As shown in FIG. 6 , the micro-speaker unit may include a housing 30 , the MEMS piezoelectric micro-speaker 31 described above, and a micro-speaker driving chip 32 . The MEMS piezoelectric micro-speaker 31 and the micro-speaker driving chip 32 are arranged in the housing 30 .

Figure 7 shows a schematic diagram of an electronic device according to another embodiment. The electronic device includes the micro speaker unit depicted in FIG. 6 . The electronic device may be various earplugs, headsets, portable mobile electronic devices, and the like.

In FIG. 7 , the electronic device is described by taking a true wireless stereo headset as an example. In FIG. 7 , the true wireless stereo headset includes a pair of ear tips 40 and 42 . The above-described micro speaker unit 41 is included in the earplug 40 , and the above-described micro speaker unit 43 is included in the earplug 42 .

The above are only specific implementations of the embodiments of the present disclosure. It should be noted that for those skilled in the art, some improvements and modifications can be made without departing from the principles of the embodiments of the present disclosure. , these improvements and modifications should also be regarded as the protection scope of the embodiments of the present disclosure.

Claims (10)

1. A MEMS piezoelectric micro-speaker, comprising:

   MEMS piezoelectric actuators that generate speaker sound waves; and

   The micro-microphone integrated inside the MEMS piezoelectric micro-speaker generates a sound pressure signal based on the sound wave of the speaker to adjust the sound output performance of the MEMS piezoelectric actuator, wherein the sound pressure detection part of the micro-microphone is located in the MEMS piezoelectric actuator external to the actuator and separate from the MEMS piezoelectric actuator.
2. The MEMS piezoelectric microspeaker of claim 1, wherein the micromicrophone comprises a microelectromechanical microphone die and a microphone application specific integrated circuit.
3. The MEMS piezoelectric microspeaker of claim 2, wherein the microelectromechanical microphone die is located in the back cavity of the MEMS piezoelectric microspeaker.
4. The MEMS piezoelectric microspeaker of claim 2, wherein the microelectromechanical microphone die is located in the front cavity of the MEMS piezoelectric microspeaker and is horizontally separated from the MEMS piezoelectric actuator.
5. The MEMS piezoelectric micro-speaker according to any one of claims 1 to 4, wherein the vibrating part of the micro-microphone is the MEMS piezoelectric actuator, and the detection electrode of the micro-microphone is located behind the MEMS piezoelectric micro-speaker On the substrate opposite the MEMS piezoelectric actuator in the cavity, and the detection electrodes are connected to the microphone-specific integrated circuit of the micro-microphone.
6. 6. The MEMS piezoelectric microspeaker of claim 5, wherein the microphone-specific integrated circuit is embedded in a substrate.
7. The MEMS piezoelectric microspeaker according to claim 5 or 6, wherein the substrate comprises an air outlet, and the air outlet communicates the back cavity with the outside.
8. The MEMS piezoelectric microspeaker according to any one of claims 1 to 7, wherein the MEMS piezoelectric actuator comprises a metal substrate and a piezoelectric ceramic actuating plate disposed on the metal substrate.
9. A micro-speaker unit, comprising a housing, a MEMS piezoelectric micro-speaker and a micro-speaker driving chip according to any one of claims 1 to 8, wherein the MEMS piezoelectric micro-speaker and the micro-speaker driving chip are arranged on in the housing.
10. An electronic device comprising the micro speaker unit according to claim 9.

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