Loudspeaker and electronic equipment

Abstract

The embodiment of the invention provides a loudspeaker. The loudspeaker comprises a substrate, an annular vibrating diaphragm, a cantilever structure and a driver, a through cavity is formed in the middle of the substrate; the annular vibrating diaphragm is located in the cavity and close to the top of the substrate, and the peripheral wall of the annular vibrating diaphragm is fixed to the substrate; the cantilever structure comprises more than two cantilever beams, the cantilever beams are located in an inner hole of the annular vibrating diaphragm, the outer side ends of the cantilever beams are fixed with the inner peripheral wall of the annular vibrating diaphragm, the inner side ends of the cantilever beams are free ends, and a gap is formed between every two adjacent cantilever beams; the driver is used for driving the annular vibrating diaphragm to vibrate. The loudspeaker can maintain a low THD level, and has a relatively high sound pressure level in middle and high frequency bands.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of sound - producing devices, and particularly to a loudspeaker and an electronic device. Background Art

[0002] As a commonly used electro - acoustic transducer device, loudspeakers are widely used in various electronic devices (such as terminal devices like mobile phones, tablets, earphones, etc.). Among them, piezoelectric loudspeakers have become the current mainstream research direction due to their simple structure and the ability to operate at low voltages.

[0003] In an existing piezoelectric loudspeaker, the diaphragm is a fully - enclosed structure with a high degree of constraint, which is prone to high - order nonlinear effects, limiting the overall vibration displacement of the diaphragm, resulting in a decrease in the output sound pressure level. At the same time, the nonlinear effects will also introduce harmonic distortion, leading to a reduction in sound quality. In another existing piezoelectric loudspeaker, the diaphragm is an open - type structure with a high degree of freedom, which can generate a larger displacement, but is prone to generating larger gaps, resulting in an acoustic short - circuit effect, thereby reducing the output sound pressure level and affecting the sound quality. At the same time, the diaphragm of the open - type structure has a low stiffness, and it is difficult to maintain high - frequency performance. Summary of the Invention

[0004] The embodiments of the present application provide a loudspeaker and an electronic device having the loudspeaker. The loudspeaker can maintain a relatively low THD (Total Harmonic Distortion) level through structural optimization and has a relatively high sound pressure level in the mid - to - high - frequency band.

[0005] In the first aspect of the embodiments of the present application, a loudspeaker is provided, which includes a substrate, an annular diaphragm, a cantilever structure, and a driver; a through - cavity is provided in the middle of the substrate; the annular diaphragm is located in the cavity and close to the top of the substrate, and the outer peripheral wall of the annular diaphragm is fixed to the substrate; the cantilever structure includes more than two cantilever beams. The cantilever beams are located in the inner hole of the annular diaphragm. The outer ends of the cantilever beams are fixed to the inner peripheral wall of the annular diaphragm, the inner ends of the cantilever beams are free ends, and a gap is formed between adjacent two cantilever beams; the driver is used to drive the annular diaphragm to vibrate.

[0006] With the above - mentioned arrangement, under the driving action of the driver, the outer end where the outer peripheral wall of the annular diaphragm is located uses the substrate as an anchor point, and the inner end where the inner peripheral wall is located can vibrate relative to the substrate, thereby driving the cantilever beams to vibrate together. The annular diaphragm and the cantilever beams jointly serve as a sound - producing structure. This loudspeaker forms a semi - enclosed diaphragm structure through the annular diaphragm and the cantilever structure. Through the structural constraint of the annular diaphragm, the resonance frequency can be increased under the same vibration area, the SPL in the mid - to - high - frequency band can be raised. At the same time, because the gap between adjacent two cantilever beams reduces the nonlinear effects, it is beneficial to maintain a relatively low THD level. The cantilever beams only transmit displacement and have no driving effect themselves, which can avoid the acoustic short - circuit phenomenon caused by excessive expansion of the gap during operation.

[0007] In an achievable manner, the inner end of the cantilever beam is close to the center of the cavity. In this way, the cantilever lengths of the cantilever beams are substantially the same, which is beneficial to improving the consistency of vibration.

[0008] In an achievable manner, the cantilever beams are symmetrically arranged around the center of the cavity. In this way, the consistency of vibration of the cantilever beams can be ensured, which is beneficial to reducing the nonlinear effect and improving the sound generation performance.

[0009] In an achievable manner, the driver is in a ring structure and is arranged on the ring-shaped diaphragm so that the inner peripheral side of the ring-shaped diaphragm moves relative to the substrate. The driver and the ring-shaped diaphragm may have a substantially coincident ring-shaped area so that the entire inner peripheral side of the ring-shaped diaphragm can vibrate and drive each cantilever beam to vibrate.

[0010] In an achievable manner, the driver is a piezoelectric driver, and the piezoelectric driver includes a bottom electrode layer, a top electrode layer, and a piezoelectric layer located between the bottom electrode layer and the top electrode layer; at least one of the bottom electrode layer, the top electrode layer, and the piezoelectric layer has at least one groove structure. In this way, by providing the groove structure on at least one layer structure of the piezoelectric driver, the stiffness of the overall speaker can be adjusted or the release of residual stress can be achieved, thereby regulating the resonance frequency distribution of the speaker.

[0011] Exemplarily, the material of the piezoelectric layer of the piezoelectric driver can be PZT (lead zirconate titanate), AlN (aluminum nitride), AlScN (scandium-doped aluminum nitride), ZnO (zinc oxide).

[0012] Exemplarily, the piezoelectric layer of the piezoelectric driver can be in the form of a piezoelectric thin film or a piezoelectric ceramic block.

[0013] In an achievable manner, at least part of the groove structure of the piezoelectric driver penetrates the layer structure to which it belongs in the axial direction of the speaker.

[0014] In an achievable manner, in the projection plane perpendicular to the axial direction of the speaker, the projection of the groove structure is located in the extending direction of the projection of the gap. In this way, it is convenient for processing and is also beneficial to ensuring the vibration consistency of each cantilever beam.

[0015] In an achievable manner, the piezoelectric layer is in a compressive stress state. By changing the stress state of the piezoelectric layer, the resonance frequency distribution of the speaker can be regulated. For example, the SPL output of the speaker can be tilted towards the high-frequency band to obtain a better high-frequency SPL response.

[0016] In an achievable manner, the driver includes more than two independent driving units. By this means, the stiffness of the overall speaker can be changed to adjust the sound generation performance of the speaker.

[0017] Exemplarily, each driving unit is arranged on the annular diaphragm in a centrosymmetric manner.

[0018] Exemplarily, the driver is an electrostatic driver.

[0019] In an implementable manner, within the projection plane perpendicular to the axial direction of the speaker, a part of the projection area of the driver is located within the projection area of the substrate and / or the projection area of the cantilever beam. The driver can be conveniently processed or manufactured as needed, especially in the field of MEMS; by extending the driver to the area of the cantilever beam, the stiffness of the cantilever beam can be changed, and the vibration displacement of the cantilever beam can be adjusted, thereby adjusting the sound generation performance of the speaker.

[0020] In an implementable manner, the cantilever beam and the annular diaphragm are of an integral structure, and / or the annular diaphragm and the substrate are of an integral structure.

[0021] In an implementable manner, the gap is filled with a flexible material, or the width of the gap is lower than a set value.

[0022] Filling the gap within the cantilever structure with a flexible material can avoid the phenomenon of acoustic short circuit caused by excessive expansion of the gap during operation, reduce the requirements for the gap size, and facilitate processing. Exemplarily, the flexible material filled in the gap can be organic polymer materials such as Parylene (poly-p-xylene, also known as parylene), PI (Polyimide), polypropylene, PDMS (Polydimethylsiloxane), etc.

[0023] In the case where the gap within the cantilever structure is not filled with a flexible material, by defining the upper limit value of the width of the gap, that is, setting the gap width to be lower than a set value, the phenomenon of acoustic short circuit caused by excessive expansion of the gap during the vibration of the cantilever beam can be avoided, which is beneficial to ensuring the acoustic performance of the speaker. Exemplarily, the set value is 30 - 50 μm.

[0024] In an implementable manner, the annular diaphragm has a hollowed-out structure, and / or the substrate has a hollowed-out structure. In this way, the overall stress state and resonant frequency of the speaker 10 can be adjusted.

[0025] In an implementable manner, the speaker is a MEMS speaker.

[0026] The second aspect of the embodiments of the present application provides an electronic device, including the speaker as described above. In specific applications, the electronic device can be a terminal device with a sound generation function such as a mobile phone, a computer, a tablet, a learning machine, and a smart wearable device, etc. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of the speaker in the first embodiment of the present application;

[0028] Figure 2 is Figure 1 a schematic structural view of another perspective of the loudspeaker shown;

[0029] Figure 3 is Figure 1 a top view of the loudspeaker shown;

[0030] Figure 4 is Figure 3 a sectional view taken along the line A-A in

[0031] Figure 5 is Figure 1 an exploded view of the loudspeaker shown;

[0032] Figure 6 a schematic structural view of the loudspeaker in the second embodiment of the present application;

[0033] Figure 7 is Figure 6 a schematic structural view of another perspective of the loudspeaker shown;

[0034] Figure 8 is Figure 6 a top view of the loudspeaker shown;

[0035] Figure 9 is Figure 8 a three-dimensional sectional view of the loudspeaker shown in the direction of B-B;

[0036] Figure 10 a schematic structural view of the loudspeaker in the third embodiment of the present application;

[0037] Figure 11 is Figure 10 a schematic structural view of another perspective of the loudspeaker shown;

[0038] Figure 12 is Figure 10 a top view of the loudspeaker shown;

[0039] Figure 13 is a three-dimensional sectional view of the loudspeaker shown in FIG. 12 in the direction of C-C;

[0040] Figure 14 a schematic structural view of the loudspeaker in the fourth embodiment of the present application;

[0041] Figure 15 is Figure 14 a partial enlarged view of the I part in

[0042] Figure 16 is Figure 14 a top view of the loudspeaker shown;

[0043] Figure 17 isFigure 16 Cross-sectional view in the D-D direction;

[0044] Figure 18 is Figure 16 Stereoscopic cross-sectional view of the shown loudspeaker in the E-E direction;

[0045] Figure 19 is Figure 14 Exploded view of the shown loudspeaker;

[0046] Figure 20 Schematic structural diagram of the loudspeaker in the fifth embodiment of the present application;

[0047] Figure 21 is Figure 20 Partial enlarged view of part II in [the figure];

[0048] Figure 22 is Figure 20 Stereoscopic cross-sectional view of the shown loudspeaker in the F-F direction;

[0049] Figure 23 is Figure 20 Exploded view of the shown loudspeaker;

[0050] Figure 24 is the comparison curve graph of SPL performance of the piezoelectric layer of the loudspeaker in the first embodiment under the stress-free state and the stressed state. Detailed implementation manners

[0051] The embodiment of the present application provides a loudspeaker, which can have a relatively high sound pressure level in the medium and high frequency bands while maintaining a low THD level.

[0052] The loudspeaker provided by the embodiment of the present application can be applied to various electronic devices, such as terminal devices with loudspeakers like mobile phones, tablets, headphones, etc.; the loudspeaker can be applied to sound generating devices in the field of MEMS (Micro Electro-Mechanical Systems), or can also be applied to sound generating devices in non-MEMS fields.

[0053] For the convenience of description, the following is an explanation of the noun terms involved in the present application.

[0054] THD, Total Harmonic Distortion, is an indicator of the harmonic distortion of an electrical signal. It can be understood as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency signal. The larger the total harmonic distortion, the greater the proportion of harmonic components. A lower total harmonic distortion enables the output system to generate a more accurate output signal with fewer harmonics and closer to the original sampled signal. Harmonic distortion is caused by the incomplete linearity of the system. When the system outputs a signal, in addition to the original frequency, other harmonic frequencies appear. The total harmonic distortion is a parameter that describes the proportion of these harmonic components.

[0055] SPL, Sound Pressure Level, is obtained by taking the common logarithm of the ratio of the measured sound pressure to the reference sound pressure and then multiplying by 20. The unit is decibel.

[0056] The loudspeaker provided by the embodiment of the present application includes a substrate, an annular diaphragm, a cantilever structure, and a driver. The middle of the substrate has a through cavity. The annular diaphragm is located in the cavity of the substrate and is disposed near the top of the substrate. The outer peripheral wall of the annular diaphragm is fixed to the substrate, that is, the outer peripheral wall of the annular diaphragm is anchored by the substrate. The cantilever structure includes more than two cantilever beams. The cantilever beams are located in the inner hole of the annular diaphragm. The outer ends of the cantilever beams are fixed to the inner peripheral wall of the annular diaphragm. A gap is formed between adjacent two cantilever beams, that is, the outer ends of the cantilever beams are anchored by the annular diaphragm, and the inner ends are free ends. The driver is used to drive the annular diaphragm to vibrate.

[0057] With such a setting, under the driving action of the driver, the outer end where the outer peripheral wall of the annular diaphragm is located takes the substrate as an anchor point, and the inner end where the inner peripheral wall is located can vibrate relative to the substrate, thereby driving the cantilever beams to vibrate together. The annular diaphragm and the cantilever beams jointly serve as a sounding structure.

[0058] The loudspeaker adopting the above scheme forms a semi-closed diaphragm structure through the annular diaphragm and the cantilever structure. Through the structural constraint of the annular diaphragm, the resonance frequency can be increased under the same vibration area, and the SPL in the middle and high frequency bands can be raised. At the same time, since the gap between adjacent two cantilever beams reduces the nonlinear effect, it is beneficial to maintain a relatively low level of THD. The cantilever beams only transfer displacement and have no driving effect by themselves, which can avoid the acoustic short-circuit phenomenon caused by excessive expansion of the gap during operation.

[0059] To better understand the technical solution and technical effect of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0060] Please refer to Figures 1 to 5 , Figure 1 , which is a schematic structural diagram of the loudspeaker in the first embodiment of the present application; Figure 2 is Figure 1 a schematic structural diagram of the loudspeaker shown in another perspective; Figure 3 isFigure 1 Top view of the shown loudspeaker; Figure 4 is Figure 3 Cross-sectional view taken along the line A-A in Figure 5 is Figure 1 Exploded view of the shown loudspeaker.

[0061] In this embodiment, the loudspeaker 10 includes a substrate 11, an annular diaphragm 12, a cantilever structure 13, and a driver 14.

[0062] The middle part of the substrate 11 has a through cavity 11a, which penetrates the top wall and the bottom wall of the substrate 11.

[0063] The annular diaphragm 12 is an annular closed structure with an inner hole in the middle. The annular diaphragm 12 has an inner peripheral wall relatively close to the center and an outer peripheral wall relatively far from the center. The annular diaphragm 12 is located in the cavity 11a of the substrate 11 and is arranged close to the top end of the substrate 11. The outer peripheral wall of the annular diaphragm 12 is fixed to the substrate 11, and the inner peripheral wall of the annular diaphragm 12 is closer to the center of the cavity 11a of the substrate 11 than the outer peripheral wall.

[0064] The cantilever structure 13 includes more than two cantilever beams 131, and the cantilever beams 131 are located in the inner hole of the annular diaphragm 12; the cantilever beams 131 have an outer end and an inner end. The outer end refers to the end relatively far from the center of the cavity 11a of the substrate 11, and the inner end refers to the end relatively close to the center of the cavity 11a of the substrate 11. The outer end of the cantilever beam 131 is fixed to the inner peripheral wall of the annular diaphragm 12, the inner end of the cantilever beam 131 is a free end, and a gap 132 is formed between adjacent two cantilever beams 131.

[0065] The driver 14 is used to drive the annular diaphragm 12 to vibrate.

[0066] In application, the bottom wall of the substrate 11 is arranged on structures such as a circuit board. The annular diaphragm 12 is placed at the top inside the cavity 11a of the substrate 11, the cantilever structure 13 is placed in the inner hole of the annular diaphragm 12. The annular diaphragm 12 and the cantilever structure 13 together close the top opening of the cavity 11a of the substrate 11. Also, because a gap 132 is formed between adjacent two cantilever beams 131 of the cantilever structure 13, the annular diaphragm 12, the cantilever structure 13, and the substrate 11 form a semi-closed diaphragm structure.

[0067] During operation, the driver 14 drives the annular diaphragm 12 to vibrate. Since the outer peripheral wall of the annular diaphragm 12 is fixed to the substrate 11, under the drive of the driver 14, the side where the inner peripheral wall of the annular diaphragm 12 is located (hereinafter referred to as the inner peripheral side) vibrates relative to the substrate 11, driving the cantilever beams 131 to vibrate together. The annular diaphragm 12 and the cantilever beams 13 vibrate together as a sound-generating structure.

[0068] With the above structural arrangement of the loudspeaker 10, the outer peripheral wall of the annular diaphragm 12 is anchored to the substrate 11. This structure can increase the resonance frequency under the same vibration area. At the same time, the design of the gaps 132 between adjacent cantilever beams 131 reduces the non-linear effect. The cantilever beams 131 only transmit displacement, which can avoid excessive expansion of the gaps 132 during operation and cause acoustic short circuit. Generally speaking, it can improve the SPL of the loudspeaker 10 in the mid-high frequency band and maintain a low level of THD, having good acoustic performance.

[0069] In this embodiment, the substrate 11 has a three-layer structure, which are the first layer 111, the second layer 112, and the third layer 113 in sequence from the bottom wall to the top wall of the substrate 11. The cavity 11a penetrates through the first layer 111, the second layer 112, and the third layer 113. The stacking direction of the three-layer structure of the substrate 11 is consistent with the axis direction S of the loudspeaker 10, and the axis direction S of the loudspeaker 10 is parallel to the direction where the center line of the cavity 11a is located.

[0070] The position of the annular diaphragm 12 in the cavity 11a can correspond to the position where the third layer 113 is located, that is, the outer peripheral wall of the annular diaphragm 12 is fixed to the third layer 113.

[0071] In one implementation, the annular diaphragm 12 and the third layer 113 of the substrate 11 can be an integrally formed structure, and each cantilever beam 131 of the cantilever structure 13 can also be an integrally formed structure with the annular diaphragm 12. As Figure 4 and Figure 5 shown, the inner peripheral wall of the third layer 113 of the substrate 11 extends towards the center of the cavity 11a to form the annular diaphragm 12, and the cantilever beams 131 extend from the inner peripheral wall of the annular diaphragm 12 towards the center of the cavity 11a; in the circumferential direction of the annular diaphragm 12, adjacent cantilever beams 131 are spaced apart to form gaps 132.

[0072] In Figure 4 and Figure 5 the shown examples, the third layer 113 of the substrate 11, the annular diaphragm 12, and the cantilever beams 131 are an integral structure. In Figure 4 the boundary between the annular diaphragm 12 and the third layer 113 is schematically shown by a dotted line, and in Figure 5 the areas where the third layer 113, the annular diaphragm 12, and the cantilever beams 131 are located are schematically shown by different patterns.

[0073] This structural arrangement can improve the stiffness and stability of the overall structure of the loudspeaker 10.

[0074] In other implementation manners, the annular diaphragm 12 can be fixed to the third layer 113 of the substrate 11 only by integral molding, that is, the annular diaphragm 12 and the third layer 113 are of an integral structure, and the outer end of the cantilever beam 131 is fixed to the annular diaphragm 12 by means such as bonding; alternatively, the annular diaphragm 12 and the cantilever beam 131 can be fixed only by integral molding, that is, the annular diaphragm 12 and the cantilever beam 131 are of an integral structure, and the outer peripheral wall of the annular diaphragm 12 is fixed to the third layer 113 of the substrate 11 by means such as bonding.

[0075] In other implementation manners, the number of layers of the substrate 11 can be one layer, two layers, four layers or other layers, and the fixing position of the annular diaphragm 12 to the substrate 11 can be adjusted adaptively according to the structure of the substrate 11. For example, when the substrate 11 is a two-layer structure, the annular diaphragm 12 can be integrally molded with the top layer of the substrate 11 close to the top wall or fixed by means such as bonding; when the substrate 11 is a one-layer structure, the annular diaphragm 12 can be integrally molded with the substrate 11 or fixed by means such as bonding, and the annular diaphragm 12 is arranged close to the top wall of the substrate 11.

[0076] When the speaker 10 is used in the MEMS field, the substrate 11 can be selected as an SOI (Silicon on Insulator) wafer. The SOI wafer is a three-layer structure, including a bulk silicon layer, a buried oxide layer and a top silicon layer. The bulk silicon layer is the first layer 111 of the substrate 11, the buried oxide layer is the second layer 112 of the substrate 11, and the top silicon layer is the third layer 113 of the substrate 11. The top silicon layer is used as a device layer and can be used to form the annular diaphragm 12 and the cantilever beam 131. The buried oxide layer between the bulk silicon layer and the top silicon layer is used as an electrical isolation layer. When used in the MEMS field, the substrate 11 of the speaker 10 can also be selected from other semiconductor materials.

[0077] In this embodiment, the inner ends of the cantilever beams 131 of the cantilever structure 13 are all arranged close to the center of the cavity 11a of the substrate 11. In this way, the cantilever lengths of the cantilever beams 131 are basically the same, which is beneficial to improving the consistency of vibration.

[0078] In one implementation manner, the cantilever beams 131 of the cantilever structure 13 are arranged symmetrically around the center of the cavity 11a. It can be understood that the cantilever beams 131 form a central symmetric structure, and the symmetric center is the center of the cavity 11a. With such an arrangement, the consistency of vibration of the cantilever beams 131 can be ensured, which is beneficial to reducing the non-linear effect and improving the sound generation performance.

[0079] In specific implementation, the outer dimensions of the cantilever beams 131 are the same, and the cantilever beams 131 are evenly distributed along the circumferential direction of the annular diaphragm 12.

[0080] In a specific implementation, the width dimensions of the gaps 132 of the cantilever structure 13 are the same, that is, the dimensions of the gaps 132 between any two adjacent cantilever beams 131 of the cantilever structure 13 are the same. In this way, it is beneficial to ensure the consistency of the vibration amplitudes of the cantilever beams 131, so as to improve the sound generation performance.

[0081] The gap 132 between two adjacent cantilever beams 131 should not be too large and should not exceed a set value. In other words, the width of the gap 132 between two adjacent cantilever beams 131 has an upper limit value. This can prevent the vibration displacement of the cantilever beam 131 during operation from being too large, resulting in excessive expansion of the gap 132 between two adjacent cantilever beams 131 and causing an acoustic short-circuit phenomenon.

[0082] Exemplarily, in the field of MEMS, the above set value can be selected within the range of 30 - 50 μm. In application, the value range of the set value can also be determined according to simulation or experiment.

[0083] In other implementation manners, according to the required sound generation performance, the cantilever beams 131 of the cantilever structure 13 can also be arranged in other ways, such as symmetrically arranged relative to a set axis; the outer dimensions of the cantilever beams 131 of the cantilever structure 13 can also be set to be not completely the same.

[0084] In other implementation manners, the loudspeaker 10 can also fill a flexible material in the gap 132 between two adjacent cantilever beams 131. The filling of the flexible material will not affect the vibration of the cantilever beam 131, and can reduce the dimensional requirements for the gap 132, facilitate processing, and is beneficial to reducing the manufacturing cost of the loudspeaker 10.

[0085] On the basis that the gap 132 of the cantilever structure 13 is filled with a flexible material, there are no particularly strict requirements for the width dimension of the gap 132, and the width dimension of the gap 132 can be determined according to the required performance of the loudspeaker 10.

[0086] Exemplarily, the flexible material filled in the gap 132 can be an organic polymer material such as Parylene (poly-p-xylene, also known as parylene), PI (Polyimide), polypropylene, PDMS (Polydimethylsiloxane).

[0087] In this embodiment, the driver 14 is in a ring structure and is arranged on the ring diaphragm 12, so that the inner peripheral side of the ring diaphragm 12 moves relative to the substrate 11. The driver 14 directly drives the ring diaphragm 12 to vibrate through its own vibration. The driver 14 and the ring diaphragm 12 have a substantially overlapping ring area, so that the entire inner peripheral side of the ring diaphragm 12 can vibrate and drive each cantilever beam 131 to vibrate.

[0088] The driver 14 can be a piezoelectric driver, including a bottom electrode layer 141, a top electrode layer 143, and a piezoelectric layer 142 located between the bottom electrode layer 141 and the top electrode layer 143. By applying voltage to the piezoelectric layer 142 through the bottom electrode layer 141 and the top electrode layer 143, the piezoelectric layer 142 will deform and vibrate under the action of the voltage, thereby driving the annular diaphragm 12 to vibrate.

[0089] In the MEMS field, the piezoelectric material of the piezoelectric layer 142 of the driver 14 can be selected from PZT (lead zirconate titanate), AlN (aluminum nitride), AlScN (scandium-doped aluminum nitride), ZnO (zinc oxide), etc., and the form of the piezoelectric layer 142 can be a piezoelectric thin film. In non-MEMS fields, piezoelectric ceramic blocks can be used to make piezoelectric drivers.

[0090] In one implementation, the driver 14 is an integral structure, that is, the driver 14 is in a circumferentially continuous annular structure.

[0091] Exemplarily, in the projection plane perpendicular to the axis direction S of the speaker 10, the projection area of the driver 14 completely covers the area where the annular diaphragm 12 is located. In this way, the driver 14 can provide a relatively large driving force to the annular diaphragm 12.

[0092] Exemplarily, in the projection plane perpendicular to the axis direction S of the speaker 10, a part of the projection area of the driver 14 can also be in the projection area of the substrate 11 and / or the projection area of the cantilever beam 131. In other words, a part of the projection area of the driver 14 is in the projection area of the substrate 11, or a part of the projection area of the driver 14 is in the projection area of the cantilever beam 131, or a part of the projection area of the driver 14 is in the projection area of the substrate 11 and a part is in the projection area of the cantilever beam 131. It can be understood that a part of the driver 14 can extend outward to the area where the substrate 11 is located, or a part can extend inward to the area where the cantilever beam 131 is located.

[0093] In the MEMS field, the driver 14 can be formed by semiconductor processing methods such as deposition and etching, and each film layer of the driver 14 extends to the area where the substrate 11 is located, which is convenient for the deposition process and subsequent etching and forming.

[0094] The substrate 11 serves as a border structure for anchoring the annular diaphragm 12. The partial arrangement of the driver 14 on the substrate 11 will not have a significant impact on the sound emission of the speaker 10; the cantilever beam 131 serves as a driven structure. The partial arrangement of the driver 14 on the cantilever beam 131 will increase the mass load of the cantilever beam 131, affect the vibration of the cantilever beam 131, and thus affect the sound emission performance. Generally speaking, the larger the mass load of the cantilever beam 131, the smaller the vibration displacement; the smaller the mass load of the cantilever beam 131, the larger the vibration displacement. The appropriate reduction of the mass load of the cantilever beam 131 is also beneficial to increasing the resonance frequency to enhance the response in the mid-high frequency band. In applications, it is possible to select whether the driver 14 extends to the cantilever beam 131 and the size of the area extending to the cantilever beam 131 according to the actual performance requirements of the speaker 10, and adjust the stiffness / mass of the cantilever beam 131 to meet the actual performance requirements.

[0095] In one implementation, the outer contour of the substrate 11 is generally square, and the cavity 11a has a circular structure. Correspondingly, the outer peripheral contour of the annular diaphragm 12 arranged in the cavity 11a is circular; the inner hole of the annular diaphragm 12 is also circular, that is, the annular diaphragm 12 as a whole has a circular ring structure.

[0096] In other implementations, the cavity 11a of the substrate 11 can be of other shapes, and the annular diaphragm 12 can also be of other shapes. For example, Figures 6 to 9 In the second embodiment shown, the outer contour of the substrate 11 of the speaker 10 is generally square, the cavity 11a has a square structure, and the outer peripheral contour of the annular diaphragm 12 adapted to the cavity 11a is square; the inner hole of the annular diaphragm 12 is also square.

[0097] In specific implementations, the thickness of the piezoelectric layer 142 of the driver 14 affects the magnitude of the driving force applied to the annular diaphragm 12. The thicknesses of the annular diaphragm 12 and the cantilever beam 131 also affect the sound emission performance. The performance of the speaker 10 can be adjusted by adjusting the thickness of at least one of the piezoelectric layer 142, the annular diaphragm 12, and the cantilever beam 131. For example, the speaker 10 can be maintained at a certain SPL output level in the mid-high frequency band.

[0098] In Figures 1 to 5 the first embodiment shown and Figures 6 to 9 the second embodiment shown, the outer peripheral contour shape and the inner hole shape of the annular diaphragm 12 are the same. In other implementations, the outer peripheral contour and the inner hole shape of the annular diaphragm 12 can also be different. For example, the outer peripheral contour of the annular diaphragm 12 is square, and its inner hole can be circular. The outer peripheral contour of the annular diaphragm 12 only needs to be adapted to the shape of the cavity 11a of the substrate 11, and is not limited to the circular or square shapes shown in the figure, and can also be other polygons. The inner hole of the annular diaphragm 12 is not limited to the circular or square shapes shown in the figure, and can also be elliptical or any other polygon.

[0099] In Figures 1 to 5 the first embodiment shown and Figures 6 to 9 in the second embodiment shown, there are four cantilever beams 131 disposed within the annular diaphragm 12. In Figures 1 to 5 the first embodiment shown, since the inner hole of the annular diaphragm 12 is circular, each of the adapted cantilever beams 131 is in a fan shape, and the overall outer contour formed by the four cantilever beams 131 is a circle adapted to the inner hole of the annular diaphragm 12. The four cantilever beams 131 together form four slits 132, and the four slits 132 communicate at the center of the cavity 11a of the substrate 11, and the four slits 132 are arranged in a cross shape. In Figures 6 to 9 the second embodiment shown, since the inner hole of the annular diaphragm 12 is square, each of the adapted cantilever beams 131 is in a triangular shape, and the overall outer contour formed by the four cantilever beams 131 is a square adapted to the inner hole of the annular diaphragm 12. The four cantilever beams 132 together form four slits 132, and the four slits 132 communicate at the center of the cavity 11a of the substrate 11, and the four slits 132 are arranged in an X shape.

[0100] In other implementation manners, the number of the cantilever beams 131 disposed within the annular diaphragm 12 can be other numbers, not limited to four, and can be two, three, five or more. For example, Figures 10 to 13 in the third embodiment shown, the cavity 11a of the substrate 11 of the loudspeaker 10 has a circular structure, the annular diaphragm 12 is in a circular ring shape, the cantilever structure 13 includes six cantilever beams 131, and on the basis that the inner hole of the annular diaphragm 12 is circular, each cantilever beam 131 is in a fan shape. The six cantilever beams 131 together form six slits 132, and the six slits 132 communicate at the center of the cavity 11a.

[0101] Figures 1 to 13 For the loudspeaker 10 shown, the outer contour of the substrate 11 is schematically shown as square. In other implementation manners, the outer contour of the substrate 11 can be circular or any other polygon, without limitation.

[0102] Figures 6 to 9 The loudspeaker 10 shown and Figures 10 to 13 the structural composition and the mutual relationship of the loudspeaker 10 shown are similar to those of the loudspeaker 10 shown in Figures 1 to 5 For the components or structures with the same functions in the figure, the same reference signs are used for schematic illustration, and the description of the loudspeaker 10 shown in Figures 1 to 5 can be referred to for understanding, and will not be repeated.

[0103] In Figures 1 to 13Among the speakers 10 shown, each layer structure of the driver 14 of the speaker 10 (including the bottom electrode layer 141, the piezoelectric layer 142, and the top electrode layer 143) is a circumferentially continuous and uninterrupted structure. In practical applications, the overall stiffness can be adjusted or the release of residual stress can be achieved by setting groove structures in each layer structure of the driver 14, so as to regulate the resonant frequency distribution of the speaker 10 and obtain the required performance.

[0104] Please refer to Figures 14 to 19 , Figure 14 which is a schematic structural diagram of the speaker in the fourth embodiment of the present application; Figure 15 is Figure 14 a partial enlarged view of part I in Figure 16 is Figure 14 a top view of the speaker shown; Figure 17 is Figure 16 a sectional view taken along the D-D direction in Figure 18 is Figure 16 a three-dimensional sectional view of the speaker shown in the E-E direction; Figure 19 is Figure 14 an exploded view of the speaker shown. To clearly show the differences and connections between this embodiment and the previous embodiments, the components or structures with the same functions are denoted by the same reference numerals in the figures.

[0105] In this embodiment, groove structures are provided in both the top electrode layer 143 and the piezoelectric layer 142 of the piezoelectric driver 14 of the speaker 10. For the convenience of understanding and description, the groove structure of the top electrode layer 143 is called the first groove 1441, and the groove structure of the piezoelectric layer 142 is called the second groove 1442.

[0106] In specific implementation, the number of the first grooves 1441 in the top electrode layer 143 is the same as the number of the second grooves 1442 in the piezoelectric layer 142, and the positions of the first grooves 1441 and the second grooves 1442 correspond one by one.

[0107] Each of the first grooves 1441 in the top electrode layer 143 penetrates the top electrode layer 143 in the axial direction S of the speaker 10. Thus, the top electrode layer 143 is actually divided into several relatively independent top electrode blocks 1431, and the several top electrode blocks 1431 are arranged in a ring structure around the center of the cavity 11a, that is to say, the top electrode layer 143 is discontinuously arranged in the circumferential direction.

[0108] In the illustrated example, the top electrode layer 143 is provided with four penetrating first grooves 1441, that is, the top electrode layer 143 is divided into four relatively independent top electrode blocks 1431.

[0109] The second grooves 1442 in the piezoelectric layer 142 do not penetrate the piezoelectric layer 142, and the piezoelectric layer 142 is still a circumferentially continuous ring structure.

[0110] The settings of the first groove 1441 and the second groove 1442 can change the overall stiffness of the driver 14 and also release the residual stress, so that the performance of the speaker 10 can be optimized.

[0111] The speaker 10 provided in this embodiment can be applied to the MEMS field. When applied to the MEMS field, the top electrode layer 143, the piezoelectric layer 142, and the bottom electrode layer 141 are formed by means such as deposition and etching. Generally, etching is performed from top to bottom. Therefore, to set the second groove 1442 on the piezoelectric layer 142, a through first groove 1441 is first etched on the top electrode layer 143 at the top of the piezoelectric layer 142, so that the positions of the first groove 1441 and the second groove 1442 correspond.

[0112] In this embodiment, the cantilever structure 13 of the speaker 10 is provided with four cantilever beams 131, and four gaps 132 are formed. The four first grooves 1441 of the top electrode layer 143 and the four second grooves 1442 of the piezoelectric layer 142 respectively correspond to the four gaps 132. In the projection plane perpendicular to the axis direction S of the speaker 10, the projections of the first groove 1441 and the second groove 1442 are located on the extension direction of the projection of the gap 132. When the first groove 1441, the second groove 1442, and the gap 132 are all simplified to lines, it can be considered that the projections of the first groove 1441, the second groove 1442, and the gap 132 are collinear. For reference, Figure 16 Understand.

[0113] The groove structures of the top electrode layer 143 and the piezoelectric layer 142 of the speaker 10 can also be in other forms. For example, Figures 20 to 23 In the fifth embodiment shown, in the axis direction S of the speaker 10, the first groove 1441 of the top electrode layer 143 penetrates the top electrode layer 143, and the second groove 1442' of the piezoelectric layer 142 also penetrates the piezoelectric layer 142. There are four first grooves 1441, and there are also four second grooves 1442'. The four grooves 1442' of the piezoelectric layer 142 all penetrate the piezoelectric layer 142, dividing the piezoelectric layer 142 into four piezoelectric blocks 1421, and the piezoelectric layer 142 is discontinuously arranged in the circumferential direction.

[0114] In Figures 14 to 19 the fourth embodiment shown and Figures 20 to 23 the fifth embodiment shown, the groove structures of the piezoelectric layer 142 are the same, and none of them penetrate the piezoelectric layer 142, or all of them penetrate the piezoelectric layer 142. In other implementation manners, some groove structures of the piezoelectric layer 142 can penetrate, and some groove structures do not penetrate.

[0115] In Figures 14 to 19 the fourth embodiment shown and Figures 20 to 23In the fifth embodiment shown, both the top electrode layer 143 and the piezoelectric layer 142 are provided with groove structures. In other implementation manners, the speaker 10 may also be provided with the first groove 1441 only in the top electrode layer 143, and the first groove 1441 may be provided to penetrate or not penetrate the top electrode layer 143. In other implementation manners, the speaker 10 may also be provided with at least one groove structure on each layer structure of the driver 14, and some of the groove structures may penetrate the layer structures in the axial direction S of the speaker 10. For example, the groove structure of the top electrode layer 143 penetrates the top electrode layer 143, the groove structure of the piezoelectric layer 142 penetrates the piezoelectric layer 142, and the groove structure of the bottom electrode layer 141 penetrates the bottom electrode layer 141.

[0116] In Figures 14 to 19 the fourth embodiment shown and Figures 20 to 23 in the fifth embodiment shown, in the projection plane perpendicular to the axial direction S of the speaker 10, the projection of the groove structure is located in the extending direction of the projection of the gap 132 of the cantilever structure 13. In other implementation manners, the position of the groove structure may have nothing to do with the gap 132, and the number of the groove structures may also have nothing to do with the gap 132.

[0117] In other implementation manners, if the processing permits, for example, in non-MEMS fields, when groove structures are provided on both the top electrode layer 143 and the piezoelectric layer 142, the positions of the groove structures of the two may not correspond, and the numbers may not correspond either. The groove structure of the top electrode layer 143 may also not penetrate the top electrode layer 143. If the processing permits, groove structures may also be provided only on the piezoelectric layer 142, or only on the bottom electrode layer 141, or on both the bottom electrode layer 141 and the piezoelectric layer 142. The position and number of the groove structures may or may not be adapted to the gap 132.

[0118] In Figures 14 to 19 the fourth embodiment shown and Figures 20 to 23 in the fifth embodiment shown, although the top electrode layer 143 of the driver 14 or both the top electrode layer 143 and the piezoelectric layer 142 are divided into several independent structures, the bottom electrode layer 141 is still a circumferentially continuous annular structure, and the formed driver 14 is still an integral annular structure as a whole. In other implementation manners, the driver 14 may include two or more independent driving units, and each driving unit forms an annular structure as a whole to drive the inner circumferential side of the annular diaphragm 12 to move relative to the substrate 11, so as to drive each cantilever beam 131 to vibrate. In specific implementation, each driving unit is arranged on the annular diaphragm 12 in a centrosymmetric manner to provide a relatively balanced driving force for the annular diaphragm 12. It should be noted that in the MEMS field, if groove structures penetrating the respective layer structures are provided on all three layer structures of the driver 14, then two or more relatively independent driving units will be formed.

[0119] In practical applications, the setting position, the number of settings, the arrangement method, etc. of the slot structure of the driver 14 are all set according to the performance requirements of the required speaker 10, so as to obtain a speaker 10 that meets the performance requirements.

[0120] In other implementation manners, the speaker 10 may also be provided with a hollowing structure on the annular diaphragm 12, and / or a hollowing structure is provided on the substrate 11 to adjust the overall stress state and resonance frequency of the speaker 10. The hollowing structure may be in the form of a slot or a through hole, and its shape may be regularly set or irregularly set. When the substrate 11 is provided with more than two layer structures, the hollowing structure of the substrate 11 may be provided on at least one of the layer structures.

[0121] In other implementation manners, when the driver 14 of the speaker 10 adopts a piezoelectric driver, the resonance frequency distribution of the speaker 10 may also be adjusted by controlling the stress state of the piezoelectric layer 142 of the driver 14. For example, the piezoelectric layer 142 may be in a compressive stress state to generate gain for high-frequency signals, so that the SPL output inclines towards the high-frequency band, and a better high-frequency SPL response is obtained. The magnitude of the compressive stress of the piezoelectric layer 142 may be set according to the actual performance requirements of the speaker 10. Reference may be made to Figure 24 , in order to Figures 1 to 5 take the speaker 10 shown as an example, Figure 24 FIG. shows a schematic diagram of the SPL performance comparison curves of the piezoelectric layer 142 of the driver 14 of the speaker 10 in a stress-free state and a compressive stress state. Among them, the piezoelectric layer 142 adopts an AIN piezoelectric material. The dotted line in the figure indicates the SPL frequency spectrum response curve of the speaker 10 in a stress-free state, and the solid line indicates the SPL frequency spectrum response curve of the speaker 10 in a -100 MPa stress state. It can be seen from the figure that in the mid-low frequency stage, the SPL responses of the speaker 10 in the stress-free state and the speaker 10 in the stress state are basically the same, and in the high-frequency stage, the SPL response of the speaker 10 in the stress state is better.

[0122] In other implementation manners, the driver 14 of the speaker 10 may adopt an electrostatic driver. The moving part of the electrostatic driver is provided on the annular diaphragm 12 to drive the inner peripheral side of the annular diaphragm 12 to move relative to the substrate 11. The electrostatic driver as a whole also has an annular structure, which may be an integral annular structure or an annular structure formed by enclosing a plurality of driving units.

[0123] In addition to the foregoing speaker 10, the embodiment of the present application also provides an electronic device, which includes the foregoing speaker 10 and can realize a sound generation function through the speaker 10. In a specific application scenario, the electronic device may be a terminal device with a sound generation function such as a mobile phone, a computer, a tablet, a learning machine, and a smart wearable device.

[0124] In this text, specific examples are used to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A loudspeaker, characterized in that, Comprising: A substrate having a through cavity in the middle; An annular diaphragm located within the cavity and near the top of the substrate, with the outer peripheral wall of the annular diaphragm fixed to the substrate; A cantilever structure including more than two cantilever beams. The cantilever beams are located within the inner hole of the annular diaphragm. The outer ends of the cantilever beams are fixed to the inner peripheral wall of the annular diaphragm, and the inner ends of the cantilever beams are free ends. A gap is formed between adjacent two of the cantilever beams; A driver for driving the annular diaphragm to vibrate.

2. The loudspeaker according to claim 1, characterized in that, The inner ends of the cantilever beams are close to the center of the cavity.

3. The loudspeaker according to claim 2, wherein Each of the cantilever beams is symmetrically arranged around the center of the cavity.

4. The loudspeaker according to any one of claims 1 to 3, characterized in that The driver is in an annular structure and is arranged on the annular diaphragm to enable the inner peripheral side of the annular diaphragm to move relative to the substrate.

5. The loudspeaker according to claim 4, characterized in that, The driver is a piezoelectric driver, and the piezoelectric driver includes a bottom electrode layer, a top electrode layer, and a piezoelectric layer located between the bottom electrode layer and the top electrode layer; at least one of the bottom electrode layer, the top electrode layer, and the piezoelectric layer has at least one groove structure.

6. The loudspeaker according to claim 5, characterized in that, At least part of the groove structure of the piezoelectric driver penetrates the layer structure in the axial direction of the speaker.

7. The loudspeaker according to claim 5 or 6, characterized in that, In the projection plane perpendicular to the axial direction of the speaker, the projection of the groove structure is located in the extending direction of the projection of the gap.

8. The loudspeaker according to any one of claims 5 to 7, characterized in that, The piezoelectric layer is in a compressive stress state.

9. The loudspeaker according to claim 4, characterized in that, The driver includes more than two independent driving units.

10. The loudspeaker according to claim 9, wherein Each of the driving units is symmetrically arranged around the center on the annular diaphragm.

11. The loudspeaker according to claim 4, characterized in that, The driver is an electrostatic driver.

12. The loudspeaker according to any one of claims 4-11, characterized in that, In the projection plane perpendicular to the axial direction of the speaker, part of the projection area of the driver is within the projection area of the substrate and / or the projection area of the cantilever beam.

13. The loudspeaker according to any one of claims 1-12, characterized in that, The cantilever beam and the annular diaphragm are of an integral structure, and / or the annular diaphragm and the substrate are of an integral structure.

14. The loudspeaker according to any one of claims 1-13, characterized in that, The gap is filled with a flexible material, or the width of the gap is lower than a set value.

15. The loudspeaker according to any one of claims 1 to 14, characterized in that, The annular diaphragm has a hollowed-out structure, and / or the substrate has a hollowed-out structure.

16. The loudspeaker according to any one of claims 1 to 15, characterized in that, The speaker is a MEMS speaker.

17. An electronic device, including a speaker, characterized in that, The speaker is the speaker according to any one of claims 1-16.

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