Loudspeaker and method for making the same

Abstract

The present invention provides a method for preparing a loudspeaker, and a loudspeaker obtained by the preparation method. The loudspeaker includes a base having a receiving cavity and a vibration sound-generating component received in the receiving cavity, wherein the vibration sound-generating component includes a transmission diaphragm spanning the inner wall of the base, a first diaphragm stacked on the transmission diaphragm, and a driver stacked on the transmission diaphragm to drive the transmission diaphragm and the first diaphragm to vibrate and generate sound; the transmission diaphragm and the first diaphragm have different stiffnesses. The loudspeaker architecture of the present invention realizes the deep decoupling of the driving structure and the displacement structure. The driver is only responsible for generating in-plane stress and does not warp out of the plane itself, so that the vibration of the loudspeaker is largely free from the influence of the driver's own performance, and it is easy to obtain a high level of sound pressure output in the full frequency band.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion, and in particular to a loudspeaker and a preparation method thereof. Background Art

[0002] Speakers are widely used in personal terminals and smart electronic devices, and are mainly used to convert electrical signals into sound signals. Traditional speakers usually use a dynamic structure, which has excellent low-frequency performance but lacks high-frequency hearing. At the same time, the assembly structure used by traditional speakers has significantly restricted production efficiency, which has increased production costs accordingly.

[0003] In response to the above problems, market players are trying to develop micro speakers based on MEMS (Micro-Electro-Mechanical System). The micro speakers are mainly based on piezoelectric drive mode. The use of MEMS technology can effectively improve efficiency and rapidly expand production capacity. At the same time, good high-frequency performance can be obtained by controlling the piezoelectric drive mode.

[0004] However, the existing MEMS speaker structures have not yet achieved the decoupling of the drive structure and the displacement structure, so the drive structure needs to assume the functions of providing power and displacement at the same time. There will be mutual constraints between the two, and the vibration displacement of the speaker is still greatly limited, so that the overall performance of the speaker cannot be further optimized.

[0005] Therefore, it is necessary to provide a new loudspeaker and a preparation method thereof to solve the above technical problems. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a method for preparing a loudspeaker, and a loudspeaker prepared by the method.

[0007] The present invention provides a method for preparing a loudspeaker, the method comprising the following steps:

[0008] Providing an SOI wafer, and etching a top silicon film of the SOI wafer to form the first diaphragm;

[0009] forming a bottom electrode on the first diaphragm and the buried oxide layer of the SOI wafer;

[0010] forming a piezoelectric film on the bottom electrode;

[0011] forming a top electrode on the piezoelectric film;

[0012] Etching the bottom electrode, the piezoelectric film and the top electrode respectively to form the driver;

[0013] Depositing a polymer on the first diaphragm, the driver and the buried oxide layer to form the transmission diaphragm;

[0014] Performing cavity etching on the bottom silicon film of the SOI wafer so that the buried oxide layer is partially exposed in the cavity;

[0015] The buried oxide layer exposed in the cavity is released to form the speaker.

[0016] The present invention provides a loudspeaker prepared according to the above method, the loudspeaker comprising a base having a receiving cavity and a vibration sound-generating component received in the receiving cavity, the vibration sound-generating component comprising a transmission diaphragm spanning the inner wall of the base, a first diaphragm stacked on the transmission diaphragm, and a driver stacked on the transmission diaphragm to drive the transmission diaphragm and the first diaphragm to vibrate and generate sound; wherein the transmission diaphragm and the first diaphragm have different stiffnesses.

[0017] As an improvement of the above-mentioned loudspeaker, the first diaphragm and the driver are located on the same side of the transmission diaphragm, and the first diaphragm is arranged around the driver.

[0018] As an improvement of the above-mentioned loudspeaker, the first diaphragm includes a plurality of sub-diaphragms, and the plurality of sub-diaphragms are distributed at intervals along the circumference of the transmission diaphragm.

[0019] As an improvement of the above-mentioned loudspeaker, the driver adopts a piezoelectric film driver.

[0020] The present invention provides a method for preparing a loudspeaker from another perspective, the method comprising the following steps:

[0021] Providing a piezoelectric block, and arranging electrodes and electrode lead wires on the piezoelectric block to form the driver;

[0022] Providing a base with a receiving cavity and a transmission bracket, and fixing two ends of the transmission bracket to the driver and the inner side wall of the base respectively;

[0023] The first diaphragm is arranged between the inner side wall of the base and the driver to form the loudspeaker.

[0024] The present invention further provides a loudspeaker prepared according to the method of another angle mentioned above, the loudspeaker comprising a base having a receiving cavity and a vibration and sound-generating component received in the receiving cavity, the vibration and sound-generating component comprising a transmission bracket fixed to the inner wall of the base, a first diaphragm stacked on the transmission bracket, and a driver fixed to the transmission bracket to drive the transmission bracket and the first diaphragm to vibrate and generate sound; wherein the transmission bracket and the first diaphragm have different stiffnesses.

[0025] As an improvement of the above-mentioned speaker, the transmission bracket includes a fixing portion and at least one transmission portion extending from the outer peripheral wall of the fixing portion to the inner side wall of the base and abutting against the inner side wall of the base; wherein,

[0026] The fixing portion is provided with a through hole penetrating the fixing portion in a thickness direction thereof, and the driver is inserted into the through hole.

[0027] As an improvement of the above-mentioned speaker, the transmission bracket includes a plurality of transmission parts, and the plurality of transmission parts are arranged at equal intervals along the circumference of the fixing part.

[0028] As an improvement of the above-mentioned loudspeaker, the driver adopts a piezoelectric block driver.

[0029] In the loudspeaker of the present invention, the vibration generating component includes a transmission diaphragm or a transmission bracket, which generates an in-plane expansion effect by receiving the in-plane stress generated by the driver. Based on the different stiffness between the first diaphragm and the transmission diaphragm or the transmission bracket, the first diaphragm constrains the in-plane expansion and contraction of the transmission diaphragm or the transmission bracket, thereby generating out-of-plane warping, driving the entire system to vibrate out-of-plane. The loudspeaker architecture of the present invention achieves a deep decoupling of the driving structure and the displacement structure. The driver is only responsible for generating in-plane stress and does not generate out-of-plane warping itself, so that the vibration of the loudspeaker is largely free from the influence of the driver's own performance, and it is easy to obtain a high level of sound pressure output in the full frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a loudspeaker according to an embodiment of the present invention;

[0031] Figure 2 is a cross-sectional view of a loudspeaker according to another embodiment of the present invention;

[0032] Figure 3 A schematic structural diagram of a loudspeaker according to another embodiment of the present invention;

[0033] Figure 4 is a cross-sectional view of a loudspeaker according to another embodiment of the present invention;

[0034] Figure 5 is a flowchart of a method for preparing a loudspeaker according to another embodiment of the present invention;

[0035] FIG6 is a schematic structural diagram of a method for preparing a loudspeaker according to another embodiment of the present invention;

[0036] Figure 7 It is a flowchart of a loudspeaker preparation method according to another embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] Since the current speaker structure fails to achieve decoupling of the driving structure and the displacement structure, the present invention sets a transmission structure in the speaker to transfer the in-plane stress generated by the driver through the transmission structure, so that the driver is only responsible for generating in-plane stress and does not experience out-of-plane warping itself, thereby achieving complete decoupling of force and displacement.

[0039] It should be noted that the present invention does not impose any specific limitation on the specific structure of the loudspeaker, and appropriate deformation can be made under the condition that force and displacement decoupling can be achieved.

[0040] like Figure 1 and Figure 2 As shown, one aspect of the present invention provides a first architecture of a speaker, wherein the speaker 100 includes a base 110 having a receiving cavity and a vibration sound-generating component received in the receiving cavity, wherein the vibration sound-generating component includes a transmission diaphragm 120 spanning the inner wall of the base 110, a first diaphragm 130 stacked on the transmission diaphragm 120, and a driver 140 stacked on the transmission diaphragm 120 to drive the transmission diaphragm 120 and the first diaphragm 130 to vibrate and generate sound; wherein the transmission diaphragm 120 and the first diaphragm 130 have different stiffnesses.

[0041] Please refer to Figure 2 As shown, based on the above architecture, if a dynamic input carrying an audio signal is applied to the driver 140, the driver 140 receives the above audio driving signal to generate stress and strain in the plane, and transmits the stress and strain to the transmission diaphragm 120, and the transmission diaphragm 120 generates an in-plane expansion and contraction effect by itself by receiving the stress and strain transmitted by the driver 140, and transmits the in-plane expansion and contraction to the first diaphragm 130. At the same time, the first diaphragm 130 superimposed on the transmission diaphragm 120 inhibits the in-plane expansion and contraction of the transmission diaphragm 120, that is, the first diaphragm 130 constrains the in-plane expansion and contraction of the transmission diaphragm 120, and due to the mismatch between the stiffness of the first diaphragm 130 and the stiffness of the transmission diaphragm 120, the first diaphragm 130 and the transmission diaphragm 120 undergo out-of-plane warping together, and driven by the out-of-plane warping displacement, the driver 140 also vibrates up and down out of the plane, that is, the entire structure vibrates reciprocatingly out-of-plane and restores the audio signal. That is to say, the transmission diaphragm in this example is a transmission structure, which completely decouples force and displacement. The driver is only responsible for generating in-plane stress and does not warp itself, which is equivalent to a driving structure. The transmission diaphragm and the first diaphragm form a composite warping layer, which is equivalent to a displacement structure.

[0042] Specifically, the base of this example is a base containing a closed inner receiving cavity, so that the transmission diaphragm 120 is connected across the inner wall of the base 110 to support the transmission diaphragm 120, and the first diaphragm 130 is placed on the transmission diaphragm 120 and close to the edge of the receiving cavity, and the other end of the first diaphragm 130 is close to the driver 140, and the driver 140 is arranged in the central area of ​​the transmission diaphragm 120, that is, the driver 140 and the first diaphragm 130 are connected to each other through the transmission diaphragm 120.

[0043] Further, such as Figure 1 and Figure 2 As shown, the first diaphragm 130 and the driver 140 are located on the same side (eg, the upper surface) of the transmission diaphragm 120 , and the first diaphragm 130 is disposed around the driver 140 .

[0044] Furthermore, in some other embodiments, Figure 1 As shown, the first diaphragm 130 includes a plurality of sub-diaphragms 131, which are spaced apart along the circumference of the transmission diaphragm 120. That is, the plurality of sub-diaphragms are spaced apart around the driver, and of course, the plurality of sub-diaphragms in this example are equally spaced apart.

[0045] It should be noted that this example does not specifically limit the number and shape of the sub-diaphragms, the shape of the driver and the base, and the three should be matched. For example, the multiple sub-diaphragms are in a trapezoidal structure, and correspondingly, the driver is in a polyhedral structure that matches the number of sub-diaphragms, and the base receiving cavity is also in a polyhedral shape.

[0046] For example, Figure 1 As shown, the first diaphragm 130 includes six sub-diaphragms 131, each of which is in a trapezoidal structure, and the upper bottom edge of the trapezoidal structure is close to the driver 140, and the lower bottom edge is close to the inner wall of the base 110. Correspondingly, the driver 140 is in a hexahedral structure, and the receiving cavity formed by the base 110 is also in a hexahedral shape. Of course, for those skilled in the art, other numbers of sub-diaphragms and drivers of other shapes can also be set according to actual needs.

[0047] It should be noted that since the main function of the transmission diaphragm is to transmit the stress and strain provided by the driver, the overall stiffness of the transmission diaphragm should not be too large. If the stiffness is too large, the transmission of stress and strain may be hindered.

[0048] Specifically, in some preferred embodiments, the overall stiffness of the transmission diaphragm is at least smaller than the overall stiffness of the driver.

[0049] It should be further explained that, based on the premise that the stiffness of the transmission diaphragm and the first diaphragm are different, the first diaphragm and the transmission diaphragm can arbitrarily select different materials with matching stiffness. Under the same driving force, the maximum warping displacement solution can be optimized to maximize the performance benefits of the speaker.

[0050] Furthermore, the stiffness of the driver in this example should also be reasonably configured. It should be understood that the overall stiffness of the driver should not be too large to prevent the driver from generating sufficient out-of-plane displacement. Of course, the overall stiffness of the driver should not be too small to prevent the driver from generating arched warping.

[0051] Specifically, in some embodiments, the rigidity of the driver is evenly distributed. Alternatively, in other embodiments, the rigidity of the driver is symmetrically distributed along its central axis, which can prevent the driver from warping due to uneven internal rigidity while providing driving force.

[0052] It should be noted that the driver of this example adopts a piezoelectric film driver, including a top electrode, a piezoelectric layer and a bottom electrode, wherein the piezoelectric layer is a piezoelectric film. In other words, the driver of this example can be completed by MEMS processing. It should be understood that the driver of this example can be a piezoelectric drive mode, but it is not limited to the piezoelectric drive mode, and any drive mode that can generate and transmit stress and strain, such as electrostatic drive and electromagnetic drive, can also be used.

[0053] It should be noted that the piezoelectric material used in the piezoelectric layer of this example includes but is not limited to lead zirconate titanate (PZT), aluminum nitride (AlN), zinc oxide (ZnO), etc., and no specific limitation is made to this.

[0054] like Figure 3 and Figure 4 As shown, another aspect of the present invention provides a second structure of a speaker, wherein the speaker 100 includes a base 110 having a receiving cavity and a vibration sound-generating component received in the receiving cavity, wherein the vibration sound-generating component includes a transmission bracket 150 fixed to the inner wall of the base 110, a first diaphragm 130 stacked on the transmission bracket 150, and a driver 140 fixed to the transmission bracket 150 to drive the transmission bracket 150 and the first diaphragm 130 to vibrate and generate sound; wherein the transmission bracket 150 and the first diaphragm 130 have different stiffnesses.

[0055] It should be understood that the working principle of the speaker in this example is the same as that of the speaker formed by the first structure mentioned above, and will not be repeated here.

[0056] Specifically, the base of this example is also a base containing a closed inner receiving cavity, so that the transmission bracket 150 is fixed on the inner wall of the base 110 to support the transmission bracket 150, and the first diaphragm 130 is placed below the transmission bracket 150 and close to the edge of the receiving cavity. The other end of the first diaphragm 130 abuts against the driver 140, and the driver 140 is arranged in the central area of ​​the transmission bracket 150.

[0057] It should be noted that the transmission structure of this example is a transmission bracket, that is, a bracket with a certain rigidity is used. Figure 3 to Figure 4 As shown, the transmission bracket 150 includes a fixing portion 151 and at least one transmission portion 152 extending from the outer peripheral wall of the fixing portion 151 to the inner wall of the base 110 and abutting against the inner wall of the base 110; wherein the fixing portion 151 is provided with a through hole running through its thickness direction, and the driver 140 is penetrated in the through hole.

[0058] It is still necessary to explain that the fixing portion on the transmission structure of this example is located in the central area thereof, so that the driver is inserted into the through hole and is also arranged in the central area of ​​the base receiving cavity.

[0059] Furthermore, in some embodiments, Figure 3 As shown, the transmission bracket 150 includes a plurality of transmission parts 152 , and the plurality of transmission parts 152 are arranged at equal intervals along the circumference of the fixing part 151 .

[0060] It should be noted that this example does not specifically limit the shape of the fixing part, the shape of the driver, and the shape and number of the transmission part. Figure 3 As shown, the fixing part 151 is annular, and correspondingly, the driver 140 is also circular, and the transmission bracket 150 includes six transmission parts 152, and the transmission parts 152 are rod-shaped. Of course, for those skilled in the art, other shapes of fixing parts, drivers and transmission parts can also be set.

[0061] It should be further explained that this example does not specifically limit the structure of the base. For example, in some embodiments, it can be a circular ring structure. Of course, in other embodiments, it can also be a triangular ring structure or other polygonal ring structures.

[0062] It still needs to be explained that, since the main function of the transmission bracket is to transmit the stress and strain provided by the driver, the overall stiffness of the transmission bracket should not be too large. If the stiffness is too large, the transmission of stress and strain may be hindered.

[0063] Specifically, in some preferred embodiments, the overall stiffness of the transmission bracket is at least smaller than the overall stiffness of the driver.

[0064] It still needs to be explained that, based on the premise that the stiffness of the transmission bracket and the first diaphragm are different, the first diaphragm and the transmission bracket can arbitrarily select different materials with matching stiffness. Under the same driving force, the maximum warping displacement solution can be optimized to maximize the performance benefits of the speaker.

[0065] Furthermore, the stiffness of the driver in this example should also be reasonably configured, and its overall stiffness should not be too large to prevent insufficient out-of-plane displacement. Of course, the overall stiffness of the driver should not be too small to prevent itself from arching and warping.

[0066] Specifically, in some embodiments, the rigidity of the driver is evenly distributed. Alternatively, in other embodiments, the rigidity of the driver is symmetrically distributed along its central axis, which can prevent the driver from warping due to uneven internal rigidity while providing driving force.

[0067] It should still be noted that the driver of this example uses a piezoelectric block driver and still adopts a piezoelectric drive mode, but the material selected is a piezoelectric block, and compared with the MEMS processing technology, this variant structure is easier to process using traditional assembly technology.

[0068] like Figure 5 As shown, another aspect of the present invention provides a method S200 for preparing the loudspeaker of the first structure described above, the method comprising the following steps S210-S280:

[0069] S210, provide an SOI wafer 160, which includes a bottom silicon film 161, a buried oxide layer 162 formed by silicon oxide, and a top silicon film 163 stacked in sequence from bottom to top. First, the SOI wafer 160 is cleaned, and the top silicon film 163 of the SOI wafer 160 is etched to form a first diaphragm 130, please refer to Figure 6 (ab).

[0070] S220 , forming a bottom electrode 141 on the first diaphragm 130 and the buried oxide layer 162 of the SOI wafer 160 , that is, depositing a bottom metal electrode on the first diaphragm and the buried oxide layer, please refer to FIG. 6( c ).

[0071] S230 , forming a piezoelectric film 142 on the bottom electrode 141 , that is, depositing a piezoelectric film on the bottom electrode, please refer to FIG. 6( d ).

[0072] S240 , forming a top electrode 143 on the piezoelectric film 142 , that is, depositing a top metal electrode on the piezoelectric film, please refer to FIG. 6( e ).

[0073] S250 , etching the bottom electrode 141 , the piezoelectric film 142 , and the top electrode 143 respectively to form the driver 140 , please refer to FIG. 6( f ).

[0074] S260 , depositing a polymer on the first diaphragm 130 , the driver 140 and the buried oxide layer 162 to form the transmission diaphragm 120 , please refer to FIG. 6( g ).

[0075] S270 , performing cavity etching on the bottom silicon film 161 of the SOI wafer 160 , so that the buried oxide layer 162 is partially exposed in the cavity, that is, etching the back cavity, please refer to FIG. 6( h ).

[0076] S280 , releasing the buried oxide layer 162 exposed in the cavity, ie, releasing the oxide layer, and completing the manufacturing to form the loudspeaker 100 , please refer to FIG. 6 ( i ).

[0077] It should be noted that in this example preparation method, the bottom silicon film and buried oxide layer in the central area are removed, so that only the edge area of ​​the SOI wafer remains, forming the base of the speaker.

[0078] It should be further explained that, in this example, the stiffness requirements for the first diaphragm, the transmission diaphragm and the driver can refer to the speaker of the first architecture described above, and will not be repeated here.

[0079] like Figure 7 As shown, another aspect of the present invention provides a method S300 for preparing the loudspeaker of the first structure described above, the method comprising the following steps S310-S330:

[0080] S310, providing a piezoelectric block, and setting electrodes and electrode lead wires on the piezoelectric block to form a driver.

[0081] S320, respectively fix the two ends of the transmission bracket to the driver and the inner wall of the base.

[0082] S330, a first diaphragm is arranged between the inner wall of the base and the driver, and the first diaphragm and the transmission bracket are made of materials with different stiffness, and the first diaphragm is attached to the bottom of the transmission bracket to form a speaker.

[0083] It should be noted that, in this example, the stiffness requirements for the first diaphragm, the transmission bracket and the driver can refer to the speaker of the second architecture described above, and will not be repeated here.

[0084] The present invention provides a loudspeaker and a method for preparing the same, which have the following beneficial effects compared to the prior art: a vibration generating component includes a transmission diaphragm or a transmission bracket, which generates an in-plane expansion and contraction effect by receiving the in-plane stress generated by a driver, and then based on the different stiffness of the first diaphragm and the transmission diaphragm or the transmission bracket, the first diaphragm constrains the in-plane expansion and contraction of the transmission diaphragm or the transmission bracket to generate out-of-plane warping, driving the entire system to vibrate out-of-plane. The loudspeaker architecture of the present invention achieves a deep decoupling of the drive structure and the displacement structure, the driver is only responsible for generating in-plane stress, and does not generate out-of-plane warping itself, so that the vibration of the loudspeaker is largely free from the influence of the driver's own performance, and it is easy to obtain a high level of sound pressure output in the full frequency band.

[0085] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a loudspeaker, It is characterized in that The method comprises the following steps: Providing an SOI wafer, and etching a top silicon film of the SOI wafer to form a first diaphragm; forming a bottom electrode on the first diaphragm and the buried oxide layer of the SOI wafer; forming a piezoelectric film on the bottom electrode; forming a top electrode on the piezoelectric film; Etching the bottom electrode, the piezoelectric film and the top electrode respectively to form a driver; Depositing a polymer on the first diaphragm, the driver and the buried oxide layer to form a transmission diaphragm, wherein the transmission diaphragm has a different stiffness from the first diaphragm; Performing cavity etching on the bottom silicon film of the SOI wafer so that the buried oxide layer is partially exposed in the cavity; The buried oxide layer exposed in the cavity is released to form the speaker.

2. A loudspeaker prepared according to the method for preparing a loudspeaker according to claim 1, It is characterized in that The speaker includes a base with a receiving cavity and a vibration and sound-generating component received in the receiving cavity, wherein the vibration and sound-generating component includes a transmission diaphragm spanning the inner wall of the base, a first diaphragm stacked on the transmission diaphragm, and a driver stacked on the transmission diaphragm to drive the transmission diaphragm and the first diaphragm to vibrate and generate sound; wherein the transmission diaphragm and the first diaphragm have different stiffnesses.

3. The loudspeaker according to claim 2, It is characterized in that The first diaphragm and the driver are located on the same side of the transmission diaphragm, and the first diaphragm is arranged around the driver.

4. The loudspeaker according to claim 2, It is characterized in that The first diaphragm includes a plurality of sub-diaphragms, and the plurality of sub-diaphragms are distributed at intervals along the circumference of the transmission diaphragm.

5. The loudspeaker according to any one of claims 2 to 4, It is characterized in that The driver adopts a piezoelectric film driver.

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