Loudspeaker

Abstract

According to the loudspeaker provided by the embodiment of the utility model, the cantilever beam structure is arranged, the cantilever beam structure is connected with the vibrating diaphragm through the connecting structure, the body of the substrate is enclosed to form the cavity, and the orthographic projection part of the cantilever beam on the substrate is located in the cavity, so that when the cantilever beam vibrates, sufficient space can be provided, and the thickness of the substrate is ensured to be uniform in the thickness direction of the substrate. And the cantilever beam can realize large enough deformation or displacement. The vibrating diaphragm is connected with the cantilever beam structure through the connecting structure to form a structure of the cantilever beam and the vibrating diaphragm top cover, so that the effective vibration area can be increased in a three-dimensional space, the chip size can be reduced, and the production cost can be reduced. The distance between the cantilever beams is larger than a set threshold value, so that when the cantilever beams vibrate, the vibration displacement of the cantilever beams can be larger. The cantilever beam is connected with the diaphragm through the connecting structure, and the vibration of the cantilever beam drives the diaphragm to vibrate, so that the vibration displacement of the cantilever beam is large, the displacement of the diaphragm can be increased accordingly, and the sound pressure level output by the loudspeaker is further improved.

Description

TECHNICAL FIELD

[0001] The utility model embodiment relates to acoustoelectricity technical field, especially a kind of loudspeaker. BACKGROUND

[0002] With the development of acoustoelectricity technology, the demand for loudspeakers has gradually shifted from large and heavy designs to small, high-performance and high-precision directions.

[0003] Piezoelectric Micro-Electro-Mechanical Systems (MEMS) loudspeakers are a type of miniature acoustic device based on the piezoelectric effect, used to convert electrical signals into sound waves. Piezoelectric MEMS technology combines the characteristics of MEMS and piezoelectric materials, enabling loudspeakers to achieve small size, high performance and high precision sound output.

[0004] However, in the prior art, piezoelectric MEMS loudspeakers have the problem of small diaphragm displacement. INVENTION CONTENTS

[0005] The utility model provides a kind of loudspeaker, to realize the increase of diaphragm displacement, on the basis of realizing small, high-performance and high-precision, improve the sound pressure level of loudspeaker output.

[0006] The utility model embodiment provides a kind of loudspeaker, comprising:

[0007] A substrate, the substrate includes a body and a cavity formed by the body;

[0008] A cantilever beam structure, the cantilever beam structure includes a plurality of cantilever beams, the cantilever beam is arranged on one side of the substrate, one end of the cantilever beam is located in the body, and the part of the cantilever beam projected on the substrate is located in the cavity; The distance between each cantilever beam is greater than a set threshold value;

[0009] A diaphragm, the diaphragm is located on the side of the cantilever beam structure away from the substrate;

[0010] A connecting structure, the connecting structure is located between the cantilever beam structure and the diaphragm, and connects the cantilever beam structure and the diaphragm respectively.

[0011] Optionally, the cantilever beam structure is center-symmetric or axis-symmetric; the distance between any two cantilever beams is greater than the width of the cantilever beam.

[0012] Optionally, the cantilever beam includes a first structure part and a second structure part, and the first structure part is perpendicular to the second structure part.

[0013] Optionally, the cantilever beam includes a first end and a second end, wherein the first end is fixed to the body, and the second end is suspended; the cantilever beam includes a bottom electrode, a piezoelectric layer and a top electrode which are sequentially stacked from the substrate to the diaphragm.

[0014] Optionally, the connecting structure comprises at least one columnar structure.

[0015] Optionally, the connecting structure comprises a plurality of columnar structures, and the columnar structures are connected to the cantilever beams one by one.

[0016] Alternatively, the cantilever beams are connected to the diaphragm through the same columnar structure.

[0017] Optionally, the orthographic projection of the connecting structure on the diaphragm is located in the central region of the diaphragm, and the central region of the diaphragm is a circular region with the center of the diaphragm as the center and a first set size as the radius.

[0018] Optionally, the cavity is located in the central region of the base, and the central region of the base is a circular region with the center of the base as the center and a second set size as the radius.

[0019] The orthographic projection of the center of the diaphragm on the base coincides with the center of the base.

[0020] Optionally, the orthographic projection of the connecting structure on the base is located in the cavity.

[0021] Optionally, the connecting structure and the diaphragm are an integral structure.

[0022] The loudspeaker provided in the embodiment of the present application is provided with a cantilever beam structure, the cantilever beam structure is connected to the diaphragm through a connecting structure, one end of the cantilever beam is fixed to the base body, the base body encloses to form a cavity, and the orthographic projection of the cantilever beam on the base is located in the cavity, so that the cantilever beam has sufficient space when vibrating, and the cantilever beam can realize large deformation or displacement in the thickness direction of the base. The diaphragm is connected to the cantilever beam structure through the connecting structure to form a structure of the cantilever beam plus the diaphragm top cover, the effective vibration area can be increased in the three-dimensional space, the area of the loudspeaker chip on the wafer is hardly changed, the chip size is further reduced, and the production cost is reduced. In addition, the distance between the cantilever beams is greater than a set threshold in the embodiment of the present application, so that the vibration displacement of the cantilever beam can be large when the cantilever beam vibrates. The cantilever beam is connected to the diaphragm through the connecting structure, the vibration of the cantilever beam drives the diaphragm to vibrate, so that the vibration displacement of the cantilever beam is large, the displacement of the diaphragm is increased, and the sound pressure level output by the loudspeaker is improved. In addition, the loudspeaker provided in the embodiment of the present application is a piezoelectric MEMS loudspeaker, and the miniaturization, high efficiency and high precision of the loudspeaker can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a top view of a loudspeaker provided in the embodiment of the present application;

[0024] Figure 2 is a side view of a loudspeaker provided in the embodiment of the present application.

[0025] Figure 3 is Figure 1 a sectional view of the loudspeaker shown in FIG. 1 along AA';

[0026] Figure 4 is Figure 1 a sectional view of the loudspeaker shown in FIG. 1 along BB';

[0027] Figure 5 is a schematic diagram of the step procedure before and after forming the piezoelectric layer;

[0028] Figure 6 is a schematic diagram of the step procedure after forming the piezoelectric layer and before forming the top electrode;

[0029] Figure 7 is a schematic diagram of the step procedure after forming the top electrode and before forming the bottom electrode;

[0030] Figure 8 is a schematic diagram of the step procedure after forming the bottom electrode and before forming the diaphragm layer;

[0031] Figure 9 is a schematic diagram of the step procedure of forming the diaphragm layer to the completion of the loudspeaker preparation. DETAILED DESCRIPTION

[0032] The utility model will be further described in detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the utility model, and not limited to the utility model. In addition, it should be noted that in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.

[0033] Figure 1 is a top view of a loudspeaker provided by an embodiment of the utility model, Figure 2 is a side view of a loudspeaker provided by an embodiment of the utility model, Figure 3 is Figure 1 a sectional view of the loudspeaker shown in FIG. 1 along AA'; Figure 4 is Figure 1 a sectional view of the loudspeaker shown in FIG. 1 along BB'; Figures 1-4The loudspeaker comprises a base 110, the base 110 comprising a body 101 and a cavity 102 enclosed by the body 101; a cantilever beam structure, the cantilever beam structure comprising a plurality of cantilever beams 120, the cantilever beams 120 being arranged on one side of the base 110, one end of the cantilever beams 120 being located on the body, and the part of the cantilever beams 120 in orthographic projection on the base 110 being located in the cavity 102; the distance between each of the cantilever beams 120 is greater than a set threshold; a diaphragm 130, the diaphragm 130 being located on the side of the cantilever beam structure away from the base 110; a connecting structure 140, the connecting structure 140 being located between the cantilever beam structure and the diaphragm 130 and connecting the cantilever beam structure and the diaphragm 130 respectively.

[0034] It should be noted that, Figure 3 and Figure 4 The diaphragm 130 is not shown in the figures.

[0035] The loudspeaker can be formed based on a MEMS process. The base 110 can be silicon on insulator (SOI) on an insulating substrate.

[0036] Specifically, the cantilever beam structure is located on one side of the base 110, the cantilever beam structure comprises a plurality of cantilever beams 120, and the edges of the cantilever beams 120 are located on the body of the base 110, and the end of the cantilever beams 120 on the body can be fixed with the body. Each of the cantilever beams 120 can comprise two ends, respectively denoted as a first end and a second end, wherein the first end is fixed with the body of the base, and the second end is suspended, i.e. the orthographic projection of the second end on the base 110 is located in the cavity 102. The part of the cantilever beams 120 in orthographic projection on the base 110 is located in the cavity 102, which can provide sufficient space for the cantilever beams 120 to vibrate, so as to ensure that the cantilever beams 120 can realize a large enough deformation or displacement in the thickness direction of the base 110. In an optional embodiment of the present application, the cantilever beams 120 can comprise a bottom electrode 121, a piezoelectric layer 122 and a top electrode 123 which are sequentially stacked from the base 110 to the diaphragm 130.

[0037] In the present embodiment, the loudspeaker further comprises a connecting structure 140 and a diaphragm 130, the connecting structure 140 connecting the cantilever beam structure and the diaphragm 130, and when the cantilever beam structure vibrates, the diaphragm 130 also vibrates to emit sound. The diaphragm 130 is a flexible diaphragm 130 to ensure that it can have a large enough elastic deformation. The material of the diaphragm 130 can be silicon, and the material of the connecting structure 140 can also be silicon.

[0038] The distance between each cantilever beam 120 is greater than a set threshold, so that when the cantilever beam 120 vibrates, the vibration displacement of the cantilever beam 120 can be large. The cantilever beam 120 is connected to the diaphragm 130 through the connecting structure 140, and the vibration of the cantilever beam 120 drives the diaphragm 130 to vibrate. Therefore, the vibration displacement of the cantilever beam 120 is large, which can increase the displacement of the diaphragm 130. According to the acoustic distance, the sound pressure level output by the loudspeaker is positively correlated with the displacement of the diaphragm 130. Therefore, the increase in the displacement of the diaphragm 130 can increase the sound pressure level output by the loudspeaker. In addition, the diaphragm 130 is connected to the cantilever beam structure through the connecting structure 140 to form a structure of the cantilever beam 120 plus the diaphragm 130 top cover. This structure can increase the effective vibration area in the three-dimensional space without changing the area of the loudspeaker chip on the wafer, which is conducive to reducing the size of the chip and reducing the production cost.

[0039] The loudspeaker of the embodiment is provided with a cantilever beam structure. The cantilever beam structure is connected to the diaphragm through a connecting structure, and one end of the cantilever beam is fixed to the body of the base. The body of the base encloses a cavity, and the part of the cantilever beam that is orthogonally projected on the base is located in the cavity. This can provide sufficient space for the cantilever beam to deform or displace sufficiently in the thickness direction of the base. The diaphragm is connected to the cantilever beam structure through the connecting structure to form a structure of the cantilever beam plus the diaphragm top cover. This structure can increase the effective vibration area in the three-dimensional space without changing the area of the loudspeaker chip on the wafer, which is conducive to reducing the size of the chip and reducing the production cost. In addition, the distance between each cantilever beam in the embodiment is greater than a set threshold, which further increases the vibration displacement of the cantilever beam when the cantilever beam vibrates. The cantilever beam is connected to the diaphragm through the connecting structure, and the vibration of the cantilever beam drives the diaphragm to vibrate. Therefore, the vibration displacement of the cantilever beam is large, which can increase the displacement of the diaphragm, thereby increasing the sound pressure level output by the loudspeaker. In addition, the loudspeaker of the embodiment is a piezoelectric MEMS loudspeaker, which can realize the miniaturization, high efficiency and high precision of the loudspeaker.

[0040] On the basis of the above technical solution, the cantilever beam structure can be center-symmetric or axis-symmetric.

[0041] The cantilever beam structure is center-symmetric or axis-symmetric, including the shape of the orthographic projection of the cantilever beam structure on the base 110. In this way, the uniformity of the diaphragm 130 vibration can be ensured, the distortion performance and manufacturing yield of the loudspeaker can be improved, and the product performance and yield can be improved.

[0042] On the basis of the above technical solution, the distance between any two cantilever beams is greater than the width of the cantilever beam, so that the distance between the cantilever beams is large enough to allow the cantilever beams to vibrate with a large displacement. Correspondingly, the diaphragm can vibrate with a large displacement.

[0043] Continue to refer to Figure 1 Optionally, the cantilever beam 120 includes a first structural part 121 and a second structural part 122, with the first structural part 121 perpendicular to the second structural part 122.

[0044] like Figure 1 As shown, the cantilever beam 120 includes a first structural portion 121 and a second structural portion 122, the first structural portion 121 and the second structural portion 122 being formed perpendicularly to each other as shown in the figure. Figure 1 The "L"-shaped cantilever beam 120 is shown. In an optional embodiment of this utility model, the first structural portions 121 of each cantilever beam 120 are parallel to each other, and the second structural portions 122 of each cantilever beam 120 are also parallel to each other. In this case, the distance between any two cantilever beams 120 can refer to the distance between the first structural portions 121 of the two cantilever beams 120, or it can refer to the distance between the second structural portions 122 of the two cantilever beams 120.

[0045] Based on the above embodiments, optionally, the connection structure 140 includes at least one columnar structure.

[0046] In one optional embodiment of this utility model, the cross-section of the columnar structure can be circular, that is, the columnar structure can be a cylindrical structure. In other optional embodiments of this utility model, the cross-section of the columnar structure can also be rectangular, trapezoidal, or other shapes, and this utility model embodiment does not impose specific limitations here.

[0047] Optionally, the connecting structure 140 includes multiple columnar structures, which are connected one-to-one with the cantilever beams 120; that is, each cantilever beam 120 is connected to the diaphragm 130 through a columnar structure, so that when each cantilever beam 120 vibrates, the diaphragm 130 can be driven to vibrate through the corresponding connecting structure 140, thus ensuring the reliability of vibration transmission.

[0048] In another optional embodiment of the present invention, the connecting structure 140 includes a columnar structure, and each cantilever beam 120 is connected to the diaphragm 130 through the same columnar structure.

[0049] Specifically, each cantilever beam 120 is connected to the diaphragm 130 through the same columnar structure. Correspondingly, the columnar structure is set at the ends of each cantilever beam 120 that are close to each other. The vibration of each cantilever beam 120 is transmitted to the diaphragm 130 through the same columnar structure. This can reduce the number of holes in the fabrication process, which only requires forming a through hole corresponding to a columnar structure to form the connection structure 140, thus simplifying the fabrication process.

[0050] On the basis of the above embodiments, optionally, the connecting structure 140 and the diaphragm 130 are an integral structure, and correspondingly, the materials of the connecting structure 140 and the diaphragm 130 are also the same. In the preparation of the loudspeaker, the connecting structure 140 and the diaphragm 130 can be formed in one process, which is beneficial to simplify the preparation process.

[0051] Optionally, the orthographic projection of the connecting structure 140 on the diaphragm 130 is located in the central region of the diaphragm 130, and the central region of the diaphragm 130 is a circular region with the center of the diaphragm 130 as the center and a first set size as the radius. In this way, when the cantilever beam 120 vibrates, the central region of the diaphragm 130 is driven to vibrate to drive the diaphragm 130 to vibrate. Compared with the orthographic projection of the connecting structure 140 on the diaphragm 130 being located in the edge region of the diaphragm 130, the diaphragm 130 can be made to displace more, thereby improving the sound pressure level of the loudspeaker.

[0052] Optionally, the cavity 102 is located in the central region of the base 110, and the central region of the base 110 is a circular region with the center of the base 110 as the center and a second set size as the radius. The orthographic projection of the center of the diaphragm 130 on the base 110 coincides with the center of the base 110. The second set size is greater than the first set size.

[0053] Specifically, the orthographic projection of the connecting structure 140 on the diaphragm 130 is located in the central region of the diaphragm 130, and the cavity 102 is arranged in the central region of the base 110 to provide sufficient space for the vibration of the cantilever beam 120 and the diaphragm 130. Correspondingly, the orthographic projection of the connecting structure 140 on the base 110 is located in the cavity 102.

[0054] The preparation process of the loudspeaker is introduced below.

[0055] Figure 5 is a schematic diagram of the steps of forming a piezoelectric layer and before forming a piezoelectric layer. Referring to Figure 5 The preparation method of the loudspeaker includes S1, providing a base; the base 110 can be SOI, and the SOI can include two silicon layers (for example, denoted as a first silicon layer 111 and a second silicon layer 113) and a silicon oxide layer 112 between the two silicon layers.

[0056] S2, forming a lower electrode layer 1210 on one side of the base 110;

[0057] S3, forming a piezoelectric layer 1220 on one side of the first electrode layer 1210. The piezoelectric layer 1220 is a piezoelectric film.

[0058] In the above S2 and S3 steps, the lower electrode layer 1210 and the piezoelectric layer 1220 can be formed by using a sputtering process.

[0059] Figure 6 is a schematic diagram of the step process from forming the piezoelectric layer to forming the top electrode. Referring to Figure 6 After the above S3 step, further comprising:

[0060] S4, spin-coating photoresist 200 on the side of the piezoelectric layer 1220 away from the substrate 110.

[0061] S5, photoetching and developing the photoresist 200.

[0062] S6, patterning the piezoelectric layer 1220.

[0063] After patterning the piezoelectric layer 1220, the bottom electrode via hole and other specific structures required can be formed.

[0064] S7, removing the photoresist 200.

[0065] S8, spin-coating photoresist 200 again and performing exposure and development, leaving the photoresist 200 at the position where the top electrode is not required to be formed.

[0066] S9, forming the top electrode layer 1230 on the side of the piezoelectric layer 1220 and the photoresist 200 away from the substrate 110.

[0067] S10, performing a lift-off process to remove the photoresist 200 and the material of the top electrode layer 1230 above the photoresist 200.

[0068] Specifically, the lift-off process can adopt a Lift-off process. After S10, the top electrode and the top electrode pad, the bottom electrode pad and the connecting line are formed.

[0069] Figure 7 is a schematic diagram of the step process from forming the top electrode to forming the bottom electrode. Referring to Figure 7 After the above S10 step, further comprising:

[0070] S11, spin-coating photoresist 200 again on the side of the top electrode layer 1230 away from the substrate 110 and performing exposure and development.

[0071] S12, etching the bottom electrode layer 1210 and part of the substrate 110.

[0072] Specifically, in this step, the silicon layer in the substrate 110 close to the bottom electrode layer 1210 can be etched. When etching the bottom electrode layer 1210, ion beam etching (IBE) process can be adopted, and when etching the substrate 110, deep reactive ion etching (DRIE) process can be adopted.

[0073] S13, removing the photoresist 200.

[0074] After the S13 step, a cantilever beam structure can be formed.

[0075] Figure 8 is a schematic diagram of the step sequence from forming the bottom electrode to forming the diaphragm layer. Referring to Figure 8 After the S10 step, the method further includes:

[0076] S14, forming a sacrificial layer 300 on the side of the top electrode layer 1230 away from the substrate 110.

[0077] S15, spin-coating a photoresist 200 on the side of the sacrificial layer 300 away from the substrate 110 and performing exposure and development.

[0078] S16, etching the sacrificial layer 300 to form a via hole in the sacrificial layer 300 corresponding to the position where the connecting structure is to be formed. When etching the sacrificial layer 300, an inductively coupled plasma (ICP) etching process can be used.

[0079] S17, removing the photoresist.

[0080] Figure 9 is a schematic diagram of the step sequence from forming the diaphragm layer to completing the loudspeaker. Referring to Figure 9 After the S17 step, the method further includes:

[0081] S18, forming a diaphragm layer 1300 on the side of the sacrificial layer 300 away from the substrate 110.

[0082] The material of the diaphragm layer 1300 can be Poly-Si, and a sputtering process can be used to form the diaphragm layer 1300.

[0083] S19, spin-coating a photoresist 200 on the side of the diaphragm layer 1300 away from the substrate 110 and performing exposure and development, leaving the photoresist at the position where the diaphragm is to be formed.

[0084] S20, etching the diaphragm layer 1300 to form a diaphragm.

[0085] When etching the diaphragm layer 1300, a reactive ion etching process can be used.

[0086] S21, removing the photoresist.

[0087] S22, spin-coating a photoresist 200 on the side of the substrate 110 away from the bottom electrode layer 1210 and performing exposure and development.

[0088] S23, etching the substrate 110 to form a cavity.

[0089] Specifically, the silicon oxide layer in the substrate and the silicon layer in the substrate away from the bottom electrode layer can be etched.

[0090] S24, removing the photoresist.

[0091] After step S24, the structure of the loudspeaker is formed. As shown in Figure 9 The connecting structure 140 can be an integral structure with the diaphragm 130. The bottom electrode 121 forms the bottom electrode layer 1210, and the top electrode 123 forms the top electrode layer 1230.

[0092] It should be noted that the above only describes the preferred embodiments of the present application and the principles of the technology applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A loudspeaker, characterized by The application relates to a loudspeaker, comprising: a base, which comprises a body and a cavity enclosed by the body; a cantilever beam structure, which comprises a plurality of cantilever beams arranged on one side of the base, one end of each of the cantilever beams being located on the body, and the part of the cantilever beam structure projected on the base being located in the cavity; the distance between any two of the cantilever beams is greater than a set threshold value; a diaphragm, which is located on the side of the cantilever beam structure away from the base; a connecting structure, which is located between the cantilever beam structure and the diaphragm and connects the cantilever beam structure and the diaphragm respectively.

2. The loudspeaker of claim 1, wherein, The cantilever beam structure is centrosymmetric or axially symmetric; the distance between any two of the cantilever beams is greater than the width of the cantilever beam.

3. The loudspeaker of claim 1 or 2, wherein, The cantilever beam comprises a first structure part and a second structure part, and the first structure part is perpendicular to the second structure part.

4. The loudspeaker of claim 1, wherein, The cantilever beam comprises a first end part and a second end part, wherein the first end part is fixed to the body and the second end part is suspended; The cantilever beam comprises a bottom electrode, a piezoelectric layer and a top electrode arranged in sequence from the base to the diaphragm.

5. The loudspeaker of claim 1, wherein, The connecting structure comprises at least one columnar structure.

6. The loudspeaker of claim 5, wherein, The connecting structure comprises a plurality of columnar structures, and each of the columnar structures is connected to one of the cantilever beams one by one. Alternatively, each of the cantilever beams is connected to the diaphragm through the same columnar structure.

7. The loudspeaker of claim 1, wherein, The projection of the connecting structure on the diaphragm is located in the central region of the diaphragm, and the central region of the diaphragm is a circular region with the center of the diaphragm as the center and a first set size as the radius.

8. The loudspeaker of claim 1 or 7, wherein, The cavity is located in the central region of the base, and the central region of the base is a circular region with the center of the base as the center and a second set size as the radius; the projection of the center of the diaphragm on the base coincides with the center of the base.

9. The loudspeaker of claim 1, wherein, The projection of the connecting structure on the base is located in the cavity.

10. The loudspeaker of claim 1, wherein, The connecting structure and the diaphragm are an integral structure.

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