Damping control structure, piezoelectric loudspeaker and preparation method

Abstract

The invention relates to the technical field of semiconductor devices, in particular to a damping control structure, a piezoelectric loudspeaker and a preparation method, and the damping control structure comprises a supporting part and a damping layer; one end of the supporting piece is arranged on a substrate of the piezoelectric loudspeaker, and the damping layer is arranged at the other end of the supporting piece; a damping hole is formed in the damping layer; the damping layer comprises a first electrode, a piezoelectric layer and a second electrode which are arranged in a stacked mode, and the first electrode and the second electrode apply voltage to the piezoelectric layer so as to adjust the opening size of the damping hole in the piezoelectric layer. According to the invention, the adjustment of acoustic damping can be realized, so that the device can adapt to the acoustic requirements of different frequency ranges, and the sound quality performance of the piezoelectric loudspeaker is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a damping control structure, a piezoelectric speaker, and a preparation method thereof. Background Art

[0002] MEMS piezoelectric speakers are widely used in micro-audio systems such as wearable devices, smartphones, and headphones due to their advantages of miniaturization, high efficiency, and low power consumption. However, existing piezoelectric speakers often have difficulty effectively adjusting acoustic damping in different application scenarios, which affects sound quality. In addition, previous speakers have experienced excessive sound pressure level (SPL) peaks at the resonant frequency, resulting in significant audio signal distortion and unstable sound quality. Excessive resonance is particularly prone to occur in the high-frequency range, reducing the clarity and stability of the sound. Summary of the Invention

[0003] The purpose of this application is to provide a damping control structure, a piezoelectric speaker and a preparation method, which can realize the adjustable acoustic damping, so that the device can adapt to the acoustic requirements of different frequency ranges and effectively improve the sound quality performance of the piezoelectric speaker.

[0004] The embodiment of the present application is implemented as follows:

[0005] In the first aspect, an embodiment of the present application provides a damping control structure, which is arranged in the back cavity of a piezoelectric speaker, and includes a support member and a damping layer; one end of the support member is arranged on the substrate of the piezoelectric speaker, and the damping layer is arranged at the other end of the support member; a damping hole is opened on the damping layer; the damping layer includes a first electrode, a piezoelectric layer and a second electrode arranged in a stacked manner, and the first electrode and the second electrode apply a voltage to the piezoelectric layer to adjust the opening size of the damping hole on the piezoelectric layer.

[0006] As an optional implementation manner, the damping layer is divided into at least two adjustment areas; each of the adjustment areas has a plurality of the damping holes arranged in an array.

[0007] As an optional embodiment, a first wiring portion and a first wire are provided on the damping layer; there are multiple first wiring portions, and the multiple first wiring portions are connected to the edges of the multiple damping holes in a one-to-one correspondence through the first wire.

[0008] As an optional implementation manner, a second wiring portion and a second wire are provided on the damping layer; the second wiring portion is connected to edges of at least two of the damping holes through the second wire.

[0009] In the second aspect, an embodiment of the present application provides a piezoelectric speaker, comprising a substrate, a cantilever piezoelectric diaphragm and the above-mentioned damping control structure; the cantilever piezoelectric diaphragm is laid on the substrate; one end of the support member of the damping control structure is connected to the substrate, and there is a space between the damping layer at the other end and the cantilever piezoelectric diaphragm; the projection of the damping layer on the substrate covers the cantilever piezoelectric diaphragm.

[0010] As an optional embodiment, it also includes a circuit board and a metal packaging cover; the surface of the substrate facing away from the cantilever piezoelectric diaphragm is connected to the circuit board; the metal packaging cover is buckled on the circuit board to form a back cavity to accommodate the damping control structure.

[0011] As an optional embodiment, the support member includes an annular retaining wall structure arranged circumferentially around the cantilever piezoelectric diaphragm; the axial direction of the annular retaining wall structure is perpendicular to the substrate; the damping layer is arranged at the end of the annular retaining wall structure away from the substrate, and the damping layer is parallel to the cantilever piezoelectric diaphragm.

[0012] As an optional implementation, the damping control structure is located above the point where the cantilever piezoelectric diaphragm has the maximum displacement.

[0013] In a third aspect, an embodiment of the present application further provides a method for preparing a piezoelectric speaker, comprising:

[0014] preparing a cantilever piezoelectric diaphragm on a substrate;

[0015] A support member is prepared on a substrate, wherein the support member surrounds the circumference of the cantilever piezoelectric diaphragm to form an annular retaining wall structure;

[0016] Filling the annular retaining wall structure with a sacrificial layer covering the cantilever piezoelectric diaphragm, wherein the sacrificial layer is flush with the surface of the support member;

[0017] depositing a damping layer and etching damping holes on the damping layer;

[0018] The sacrificial layer is released through the damping hole.

[0019] As an optional implementation manner, depositing a damping layer and etching damping holes on the damping layer includes:

[0020] A first electrode, a piezoelectric layer and a second electrode are sequentially deposited on the surfaces of the support member and the sacrificial layer.

[0021] As an optional embodiment, the sequentially depositing the first electrode, the piezoelectric layer, and the second electrode on the surface of the support member and the sacrificial layer includes:

[0022] A wiring portion and a wire are provided on the surface of the second electrode, one end of the wire is connected to the wiring portion, and the other end of the wire is connected to the edge of the damping hole.

[0023] The beneficial effects of the embodiments of the present application include:

[0024] The embodiment of the present application can effectively suppress the SPL peak at the resonant frequency. When the piezoelectric speaker is close to the resonant frequency, the back cavity airflow resistance is increased by reducing the damping hole opening; the overall damping of the system is improved, thereby reducing the resonance amplitude and avoiding sound distortion. The embodiment of the present application can improve the high-frequency response and enhance the sound clarity. Since the high frequency band is prone to resonance, which is a major problem for traditional speakers, the embodiment of the present application can suppress excessive resonance by actively adjusting the damping parameters corresponding to the high frequency band, making the high-frequency output clearer and more natural. The embodiment of the present application can improve the stability and adaptability of the sound quality, since different audio content (such as music, voice, white noise) requires different damping characteristics. The dynamic damping adjustment of the embodiment of the present application enables the speaker to automatically optimize the output according to different content, thereby improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is one of the structural diagrams of the piezoelectric speaker according to an embodiment of the present application;

[0027] Figure 2 This is the second structural diagram of the piezoelectric speaker according to an embodiment of the present application;

[0028] Figure 3 This is the third structural diagram of the piezoelectric speaker according to an embodiment of the present application;

[0029] Figure 4 This is the fourth structural diagram of the piezoelectric speaker according to an embodiment of the present application;

[0030] Figure 5 This is a schematic diagram of the structure of depositing a damping layer on the surface of a support member and a sacrificial layer in an embodiment of the present application;

[0031] Figure 6 This is a schematic diagram of the structure of etching damping holes on the damping layer according to an embodiment of the present application;

[0032] Figure 7 This is a schematic diagram of the structure of the embodiment of the present application after the sacrificial layer is released.

[0033] Icons: 100-back cavity; 101-support member; 102-damping layer; 103-substrate; 104-damping hole; 105-adjustment area; 106-first wiring part; 107-first wire; 108-second wiring part; 109-second wire; 110-cantilever piezoelectric diaphragm; 111-circuit board; 112-metal packaging cover; 113-sound output cavity; 114-sacrificial layer. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. In addition, the terms "first," "second," "third," etc. are used only to distinguish the descriptions and are not to be understood as indicating or implying relative importance.

[0037] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0038] MEMS piezoelectric speakers are widely used in micro-audio systems such as wearable devices, smartphones, and headphones due to their advantages of miniaturization, high efficiency, and low power consumption. However, existing piezoelectric speakers often have difficulty effectively adjusting acoustic damping in different application scenarios, which affects sound quality. In addition, previous speakers have experienced excessive sound pressure level (SPL) peaks at the resonant frequency, resulting in significant audio signal distortion and unstable sound quality. Excessive resonance is particularly prone to occur in the high-frequency range, reducing the clarity and stability of the sound.

[0039] To solve the above technical problems, embodiments of the present application provide a damping control structure, a piezoelectric speaker, and a preparation method.

[0040] Reference Figure 1 、 Figure 2 As shown, the damping control structure provided in the embodiment of the present application is arranged in the back cavity 100 of the piezoelectric speaker, and includes a support member 101 and a damping layer 102; one end of the support member 101 is arranged on the substrate 103 of the piezoelectric speaker, and the damping layer 102 is arranged at the other end of the support member 101; a damping hole 104 is opened on the damping layer 102; the damping layer 102 includes a first electrode, a piezoelectric layer and a second electrode that are stacked, and the first electrode and the second electrode apply voltage to the piezoelectric layer to adjust the opening size of the damping hole 104 on the piezoelectric layer.

[0041] It should be noted that the back cavity 100 is an enclosed space within the piezoelectric speaker. Its volume and structure significantly influence the speaker's acoustic properties. The volume and structure of the back cavity 100 also significantly influence the resonant frequency and frequency response curve. The substrate 103 has a hole formed in it to form an acoustic cavity 113.

[0042] In the embodiment of the present application, the damping control structure is arranged in the back cavity 100 of the piezoelectric speaker, which can directly affect the propagation and reflection of sound waves in the back cavity 100, thereby achieving the regulation of the overall acoustic characteristics of the speaker.

[0043] Specifically, the embodiment of the present application changes the acoustic damping coefficient of the system by adjusting the degree of openness of the airflow channel in the back cavity 100 by adjusting the opening size of the damping hole 104. The present application designs the originally static back cavity 100 into a dynamically adjustable acoustic damping system.

[0044] It should be noted that the damping layer 102 in the embodiment of the present application comprises a sandwich structure consisting of a first electrode, a piezoelectric layer, and a second electrode. The first electrode, the piezoelectric layer, and the second electrode form a complete piezoelectric actuator. When a voltage is applied between the two electrodes, the piezoelectric layer deforms. This deformation directly affects the damping hole 104 area, thereby changing the opening size of the damping hole 104.

[0045] Therefore, the embodiment of the present application can utilize the piezoelectric effect to achieve micron-level precise control of the opening and closing of the damping hole 104, and ultimately achieve dynamic adjustment of the acoustic damping.

[0046] A DC voltage is applied to the piezoelectric layer, either positive or negative. The positive or negative voltage determines whether the piezoelectric layer opens upward or downward, while the magnitude of the voltage determines the degree of closure of the damping hole 104 in the piezoelectric layer. The corresponding hole shape varies, and the hole area can be determined based on actual conditions. For example, the damping hole 104 is a circular hole with a radius of 10 μm.

[0047] It should be noted that, during specific adjustments, voltage is used to control the deformation of the piezoelectric layer, thereby adjusting the opening size of the damping hole 104. External circuitry can intelligently adjust the applied voltage based on parameters such as the audio signal frequency and amplitude, achieving dynamic damping matching for different frequency bands (especially high frequencies). The piezoelectric layer has a fast response speed (in the microsecond range), making it suitable for real-time audio processing.

[0048] That is to say, the embodiments of the present application may also include a control system, which constructs a closed-loop control system through a controller, detects the input audio signal, and uses a control system to analyze the frequency of the audio signal. According to the analysis results, the control system adjusts the voltage applied to the piezoelectric layer to achieve damping control and ultimately achieve improvement in output sound quality.

[0049] The present embodiment dynamically adjusts system damping according to different scenarios and frequencies, utilizing the piezoelectric effect to drive deformation of the damping hole 104. This allows for high-precision, fast-response damping adjustment, reduces the resonance intensity at specific frequencies, and improves frequency response flatness. This contributes to improved overall audio quality, enhancing sound clarity and stability.

[0050] This application provides a damping control structure integrated into a piezoelectric speaker back cavity 100. By disposing a piezoelectric damping layer 102 composed of a first electrode, a piezoelectric layer, and a second electrode on a support member 101, and providing a controllable damping hole 104 therein, an external voltage is used to adjust the deformation of the piezoelectric layer to change the opening size of the damping hole 104, thereby achieving dynamic adjustment of the system's acoustic damping. This structure solves the problems of traditional piezoelectric speakers in different application scenarios, such as uncontrollable damping, severe high-frequency resonance, and unstable sound quality, thereby improving the clarity and stability of audio output. It has good application prospects and industrial value.

[0051] Specifically, the technical effects that can be produced by the embodiments of the present application are:

[0052] The embodiment of the present application can effectively suppress the SPL peak at the resonant frequency. When the piezoelectric speaker is close to the resonant frequency, the airflow resistance of the back cavity 100 is increased by reducing the opening of the damping hole 104; the overall damping of the system is improved, thereby reducing the resonance amplitude and avoiding sound distortion.

[0053] The embodiments of the present application can improve high-frequency response and enhance sound clarity. Since high-frequency bands are prone to resonance, which is a major problem for traditional speakers, the embodiments of the present application can suppress excessive resonance by actively adjusting the damping parameters corresponding to the high-frequency bands, making the high-frequency output clearer and more natural.

[0054] The embodiments of the present application can improve the stability and adaptability of sound quality. Since different audio content (such as music, speech, and white noise) requires different damping characteristics, the dynamic damping adjustment of the embodiments of the present application enables the speaker to automatically optimize the output according to different content, improving the user experience.

[0055] Reference Figure 3 、 Figure 4 As shown, as an optional embodiment, the damping layer 102 is divided into at least two adjustment areas 105; each adjustment area 105 has a plurality of damping holes 104 arranged in an array.

[0056] It should be noted that the damping layer 102 is divided into at least two adjustment zones 105 through a zoning design. Therefore, the embodiments of the present application enable independent control of different zones as needed. Each adjustment zone 105 includes multiple damping holes 104 arranged in an array. This not only helps evenly distribute sound pressure but also allows for optimization of acoustic properties by adjusting the degree of opening and closing of the damping holes 104 in different zones.

[0057] The embodiment of the present application can enhance the sound field control capability. By independently controlling the damping holes 104 in different areas, the sound field distribution of the speaker can be adjusted more finely, making the sound quality more balanced and clear.

[0058] The embodiments of the present application can enhance design flexibility. They provide greater freedom for product design through partition design and can flexibly configure the functions of each area according to the needs of actual application scenarios to meet diverse market demands.

[0059] In addition, for some complex usage scenarios, such as using headphones in a noisy environment or situations where high-fidelity sound effects are required, this design of the embodiment of the present application can achieve the best auditory experience by intelligently adjusting the state of the damping holes 104 in each area.

[0060] Reference Figure 3 As shown, as an optional embodiment, a first wiring portion 106 and a first wire 107 are provided on the damping layer 102; there are multiple first wiring portions 106, and the multiple first wiring portions 106 are connected to the edges of the multiple damping holes 104 one by one through the first wire 107.

[0061] Exemplarily, six damping holes 104 are provided on the damping layer 102 , and the six first wiring portions 106 are connected to the edges of the six damping holes 104 in a one-to-one correspondence through the first wires 107 .

[0062] Reference Figure 4As shown, as an optional embodiment, a second wiring portion 108 and a second wire 109 are provided on the damping layer 102 ; the second wiring portion 108 is connected to the edges of at least two damping holes 104 through the second wire 109 .

[0063] Exemplarily, twelve damping holes 104 are provided on the damping layer 102 , and there are six second wiring portions 108 . Each second wiring portion 108 is connected to corresponding edges of two damping holes 104 via a second wire 109 .

[0064] The shape of the damping hole 104 can be changed according to actual conditions, and can be square, circular, triangular, trapezoidal, elliptical, etc.

[0065] It should be noted that since each damping hole 104 or a group of damping holes 104 can be independently controlled by electrical signals through corresponding wiring and wires, the opening size of each damping hole 104 can be adjusted more precisely. This precision helps optimize acoustic damping, thereby improving sound quality. This arrangement allows the operating state of each damping hole 104 to be flexibly adjusted according to the needs of different application scenarios, improving the device's adaptability to various usage scenarios.

[0066] Reference Figure 1 As shown, an embodiment of the present application provides a piezoelectric speaker, including a substrate 103, a cantilever piezoelectric diaphragm 110 and the above-mentioned damping control structure; the cantilever piezoelectric diaphragm 110 is laid on the substrate 103; one end of the support member 101 of the damping control structure is connected to the substrate 103, and there is a space between the damping layer 102 at the other end and the cantilever piezoelectric diaphragm 110; the projection of the damping layer 102 on the substrate 103 covers the cantilever piezoelectric diaphragm 110.

[0067] The piezoelectric speaker provided in the embodiment of the present application integrates the piezoelectric actuator structure inside the back cavity 100, breaking through the traditional "passive" back cavity 100 design concept. Active damping adjustment is achieved through the structural design of the damping hole 104, expanding the functional boundaries of the piezoelectric speaker. It uses the inverse piezoelectric effect (i.e., electrostriction) of the piezoelectric material to control the aperture change of the damping hole 104, rather than traditional mechanical moving parts, thereby improving the system integration and reliability. In addition, the piezoelectric speaker in the embodiment of the present application can combine damping adjustment with audio signal processing to form a closed-loop control mechanism, thereby improving the intelligence level of the overall audio system.

[0068] It should be noted that the piezoelectric speaker provided in the embodiments of the present application is not only suitable for consumer electronic devices such as smartphones and headphones, but can also be extended to fields with high requirements for sound quality, such as hearing aids and car audio.

[0069] Reference Figure 1As shown, as an optional embodiment, it also includes a circuit board 111 and a metal packaging cover 112; the surface of the substrate 103 facing away from the cantilever piezoelectric diaphragm 110 is connected to the circuit board 111; the metal packaging cover 112 is buckled on the circuit board 111 to form a back cavity 100 for accommodating the damping control structure.

[0070] The metal packaging cover 112 of the embodiment of the present application is buckled onto the circuit board 111 and together with the circuit board 111 forms a closed back cavity 100 space, which plays the role of mechanical protection, electromagnetic shielding, and airtight packaging, and helps to maintain a stable internal acoustic environment.

[0071] Specifically, refer to Figure 1 、 Figure 2 As shown, the support member 101 includes an annular retaining wall structure arranged circumferentially around the cantilever piezoelectric diaphragm 110; the axial direction of the annular retaining wall structure is perpendicular to the substrate 103; the damping layer 102 is arranged at the end of the annular retaining wall structure away from the substrate 103, and the damping layer 102 is parallel to the cantilever piezoelectric diaphragm 110.

[0072] As an optional implementation, the damping control structure is located above the point where the cantilever piezoelectric diaphragm 110 has the maximum displacement.

[0073] It should be noted that the point of maximum displacement of the cantilever piezoelectric diaphragm 110 can be interpreted as the geometric center of the cantilever piezoelectric diaphragm 110. During operation, the cantilever piezoelectric diaphragm 110 has the largest amplitude at this point, and therefore the air velocity and air flow rate above the point of maximum displacement of the cantilever piezoelectric diaphragm 110 are both the highest. In this embodiment of the present application, placing the damping control structure at the point of maximum air velocity and air flow can achieve excellent damping adjustment effects. This helps further improve the audio quality of the piezoelectric speaker, enhancing sound clarity and stability.

[0074] Reference Figure 5 、 Figure 6 as well as Figure 7 As shown, the embodiment of the present application also provides a method for preparing a piezoelectric speaker, comprising:

[0075] A cantilever piezoelectric diaphragm 110 is prepared on a substrate 103;

[0076] A support member 101 is prepared on a substrate 103, and the support member 101 surrounds the circumference of the cantilever piezoelectric diaphragm 110 to form an annular retaining wall structure;

[0077] A sacrificial layer 114 covering the cantilever piezoelectric diaphragm 110 is filled into the annular retaining wall structure, and the sacrificial layer 114 is flush with the surface of the support member 101;

[0078] Depositing a damping layer 102 and etching a damping hole 104 on the damping layer 102;

[0079] The sacrificial layer 114 is released through the damping hole 104 .

[0080] It should be noted that, in the embodiment of the present application, the support member 101 can be deposited on the substrate 103 , and an annular retaining wall structure can be formed by etching the middle portion of the support member 101 .

[0081] The sacrificial layer 114 may be made flush with the surface of the support member 101 by chemical mechanical polishing.

[0082] It should be noted that after releasing the sacrificial layer 114, the cantilever piezoelectric diaphragm 110 can be etched to obtain multiple cantilever beam structures. If necessary, the cantilever piezoelectric diaphragm 110 can also be etched after being deposited on the substrate 103 but before the support member 101 is prepared to obtain multiple cantilever beam structures.

[0083] As an optional embodiment, depositing the damping layer 102 and etching the damping hole 104 on the damping layer 102 includes:

[0084] A first electrode, a piezoelectric layer and a second electrode are sequentially deposited on the surfaces of the support member 101 and the sacrificial layer 114 .

[0085] As an optional embodiment, sequentially depositing the first electrode, the piezoelectric layer, and the second electrode on the surfaces of the support member 101 and the sacrificial layer 114 includes:

[0086] A wiring portion and a wire are provided on the surface of the second electrode. One end of the wire is connected to the wiring portion, and the other end of the wire is connected to the edge of the damping hole 104 .

[0087] It should be noted that the damping layer 102 is composed of a first electrode, a piezoelectric layer, and a second electrode stacked in sequence. The two electrodes each provide an electrical path through independent wiring. By applying a DC bias voltage to the wiring, the inverse piezoelectric effect is utilized to control the opening and closing of the damping orifice 104. By adjusting the amplitude of the bias voltage, the embodiment of the present application can achieve continuous and precise control of the degree of closure of the damping orifice 104.

[0088] The embodiment of the present application is based on a dynamic damping adjustment mechanism of voltage modulation, which enables the system to compensate for fluctuations in the speaker sound pressure level in real time, thereby improving the stability of the output sound pressure level, while reducing the total harmonic distortion (THD), improving the flatness of the frequency response curve, and significantly improving the linearity and acoustic fidelity of the audio system.

[0089] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A damping control structure, arranged in a back cavity (100) of a piezoelectric speaker, characterized in that: The invention comprises a support member (101) and a damping layer (102); one end of the support member (101) is arranged on the substrate (103) of the piezoelectric speaker, and the damping layer (102) is arranged on the other end of the support member (101); a damping hole (104) is provided on the damping layer (102); the damping layer (102) comprises a first electrode, a piezoelectric layer and a second electrode which are stacked, and the first electrode and the second electrode apply a voltage to the piezoelectric layer to adjust the opening size of the damping hole (104) on the piezoelectric layer.

2. The damping control structure according to claim 1, characterized in that: The damping layer (102) is divided into at least two adjustment areas (105); each adjustment area (105) has a plurality of damping holes (104) arranged in an array.

3. The damping control structure according to claim 2, characterized in that: The damping layer (102) is provided with a first wiring portion (106) and a first wire (107); there are a plurality of first wiring portions (106), and the plurality of first wiring portions (106) are connected to the edges of the plurality of damping holes (104) in a one-to-one correspondence via the first wire (107).

4. The damping control structure according to claim 2, characterized in that: A second wiring portion (108) and a second wire (109) are provided on the damping layer (102); the second wiring portion (108) is connected to the edges of at least two of the damping holes (104) via the second wire (109).

5. A piezoelectric speaker, characterized in that: The invention comprises a substrate (103), a cantilever piezoelectric diaphragm (110) and the damping control structure according to any one of claims 1 to 4; the cantilever piezoelectric diaphragm (110) is laid on the substrate (103); one end of the support member (101) of the damping control structure is connected to the substrate (103), and a space is provided between the damping layer (102) at the other end and the cantilever piezoelectric diaphragm (110); the projection of the damping layer (102) on the substrate (103) covers the cantilever piezoelectric diaphragm (110).

6. The piezoelectric speaker according to claim 5, wherein It also includes a circuit board (111) and a metal packaging cover (112); the surface of the substrate (103) facing away from the cantilever piezoelectric diaphragm (110) is connected to the circuit board (111); the metal packaging cover (112) is buckled on the circuit board (111) to form a back cavity (100) for accommodating the damping control structure.

7. The piezoelectric speaker according to claim 5, wherein The support member (101) comprises an annular retaining wall structure arranged circumferentially around the cantilever piezoelectric diaphragm (110); the axial direction of the annular retaining wall structure is perpendicular to the substrate (103); the damping layer (102) is arranged at one end of the annular retaining wall structure away from the substrate (103), and the damping layer (102) is parallel to the cantilever piezoelectric diaphragm (110).

8. The piezoelectric speaker according to claim 5, wherein The damping control structure is located above the maximum displacement point of the cantilever piezoelectric diaphragm (110).

9. A method for preparing a piezoelectric speaker, characterized in that: include: preparing a cantilever piezoelectric diaphragm (110) on a substrate (103); A support member (101) is prepared on a substrate (103), wherein the support member (101) surrounds the circumference of the cantilever piezoelectric diaphragm (110) to form an annular retaining wall structure; Filling the annular retaining wall structure with a sacrificial layer (114) covering the cantilever piezoelectric diaphragm (110), wherein the sacrificial layer (114) is flush with the surface of the support member (101); Depositing a damping layer (102) and etching a damping hole (104) on the damping layer (102); The sacrificial layer (114) is released through the damping hole (104).

10. The method for preparing a piezoelectric speaker according to claim 9, wherein: The depositing of the damping layer (102) and etching the damping hole (104) on the damping layer (102) comprises: A first electrode, a piezoelectric layer, and a second electrode are sequentially deposited on the surfaces of the support member (101) and the sacrificial layer (114).

11. The method for preparing a piezoelectric speaker according to claim 10, wherein: The step of sequentially depositing a first electrode, a piezoelectric layer, and a second electrode on the surfaces of the support member (101) and the sacrificial layer (114) comprises: A wiring portion and a wire are provided on the surface of the second electrode, one end of the wire is connected to the wiring portion, and the other end is connected to the edge of the damping hole (104).

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