Full-band piezoelectric mems speaker and method of manufacturing the same
By integrating multiple vibration units on the MEMS speaker diaphragm layer, the problem of poor response to low-frequency signals in the existing technology is solved, and the full-band acoustic performance is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF MACAU
- Filing Date
- 2026-02-13
- Publication Date
- 2026-06-12
AI Technical Summary
Existing piezoelectric MEMS loudspeakers have a narrow frequency response range because of the micron-level physical size of the fully fixed diaphragm, which results in good response to high-frequency signals but poor response to low-frequency signals.
Several vibration units are integrated on a diaphragm layer of a MEMS loudspeaker. Each vibration unit responds to input signals of different frequency bands. By adapting vibration units with different resonant frequencies, sound pressure superposition is generated in the audible frequency range, thereby improving the full-band acoustic performance.
It achieves optimized response to low-frequency signals, expands the frequency response range, and improves full-band acoustic performance.
Smart Images
Figure CN122205331A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microelectromechanical systems (MEMS) loudspeaker technology, and in particular to a full-band piezoelectric MEMS loudspeaker and its fabrication method. Background Technology
[0002] A piezoelectric MEMS loudspeaker is a device that uses an alternating electric field to vibrate a piezoelectric actuator. The piezoelectric actuator drives a diaphragm to strike the air, converting electrical energy into sound energy. The structure of a piezoelectric MEMS loudspeaker includes a piezoelectric actuator, a fully fixed diaphragm, and a supporting substrate. The fully fixed diaphragm is fixed to the supporting substrate on all four sides. The piezoelectric actuator drives the central region of the fully fixed diaphragm, where the diaphragm vibrates with the largest amplitude, generating sound waves that radiate outwards.
[0003] In related technologies, due to the micron-level physical size of piezoelectric MEMS loudspeakers, piezoelectric MEMS loudspeakers usually use a fully fixed diaphragm. The fully fixed diaphragm has a better response to high-frequency signals, but a poor response to low-frequency signals, and the frequency response range is relatively narrow. Summary of the Invention
[0004] In view of this, embodiments of this application provide a full-band piezoelectric MEMS loudspeaker and a method for fabricating a full-band piezoelectric MEMS loudspeaker. The piezoelectric MEMS loudspeaker integrates several vibration units, with different vibration units responding to input signals in different frequency ranges, thus optimizing the response to low-frequency signals and improving the frequency response range.
[0005] To achieve the above objectives, embodiments of this application provide a full-band piezoelectric MEMS loudspeaker, including a supporting substrate layer and a diaphragm layer distributed along the thickness direction; The diaphragm layer has N vibration units disposed on the plane of the diaphragm layer. The Nth vibration unit is used to generate sound waves in response to the Nth frequency band signal, where N is an integer greater than or equal to 2. The vibration unit includes a first electrode, a piezoelectric layer and a second electrode distributed along the thickness direction. The supporting base layer has a diaphragm support on the base layer plane. The diaphragm support abuts against the diaphragm layer and is used to isolate N vibration units. The area surrounded by the diaphragm support forms a back cavity.
[0006] In some embodiments, the diaphragm layer plane includes a central region and an outer edge region, and the diaphragm layer is provided with a first vibration unit and a plurality of second vibration units; The first vibration unit is disposed in the central region, and the first vibration unit is used to generate high-frequency sound waves in the range of human ear audibility. Several second vibration units are arranged circumferentially along the central region in the outer edge region. The second vibration units are used to generate mid-frequency and low-frequency sound waves in the range of human hearing.
[0007] In some embodiments, a first slotted gap is provided between adjacent second vibration units, the first slotted gap being used to separate adjacent second vibration units.
[0008] In some embodiments, the first vibration unit is provided with a second slotted slit.
[0009] In some embodiments, the diaphragm support supports the bottom surface of the diaphragm layer around the edge of the first vibrating unit.
[0010] To achieve the above objectives, this application also provides a method for fabricating a full-band piezoelectric MEMS loudspeaker, used to fabricate the full-band piezoelectric MEMS loudspeaker described in this application embodiment. The fabrication method includes: Pre-treatment of the supporting substrate layer; A diaphragm layer is formed on the supporting substrate layer by deposition and photolithography, wherein the diaphragm layer comprises N vibration units; Etching is performed on the back side of the supporting substrate layer to form a diaphragm support and a back cavity; The supporting substrate layer and the diaphragm layer are encapsulated to obtain a MEMS loudspeaker.
[0011] In some embodiments, the diaphragm layer includes a first vibration unit, a second vibration unit, and a third vibration unit; The process of forming a diaphragm layer on the supporting substrate by deposition and photolithography includes: An insulating layer, a first electrode layer, and a piezoelectric layer are sequentially deposited on the front side of the supporting substrate layer. Photoresist is coated on the piezoelectric layer, and a diaphragm pattern is transferred through a preset mask. The diaphragm pattern includes a first vibration unit region, a second vibration unit region, and a third vibration unit region. The first electrode layer and the piezoelectric layer are etched according to the diaphragm pattern to form a first vibration unit, a second vibration unit and a third vibration unit; A second electrode layer is deposited on the etched piezoelectric layer to form a diaphragm layer.
[0012] In some embodiments, the formation of the diaphragm layer on the supporting substrate layer by deposition and photolithography further includes: A first slot is etched on the second electrode layer, wherein the first slot is disposed between the second vibration unit and the third vibration unit, and the first slot is used to separate the second vibration unit and the third vibration unit.
[0013] In some embodiments, the formation of the diaphragm layer on the supporting substrate layer by deposition and photolithography further includes: A second slot is etched on the second electrode layer, wherein the second slot is located within the first vibration unit.
[0014] In some embodiments, etching the back side of the supporting substrate to form a diaphragm support and a back cavity includes: Photoresist is coated on the back side of the supporting substrate layer, and a back cavity pattern is transferred through a preset mask. The back side of the supporting substrate layer is etched to form a diaphragm support and a back cavity; wherein the back cavity extends through the supporting substrate layer to the insulating layer, and the diaphragm support supports the diaphragm layer around the edge of the first vibrating unit.
[0015] The embodiments of this application include at least the following beneficial effects: This application provides a full-range piezoelectric MEMS loudspeaker and a method for fabricating it. The method integrates several vibration units on a diaphragm layer of the MEMS loudspeaker. Each vibration unit responds to input signals at different frequency bands, generating sound at those bands. When a voltage is applied to the MEMS loudspeaker, the vibration units adapted to different resonant frequencies respond to low, mid, and high-frequency acoustic signals respectively, achieving sound pressure level superposition within the audible frequency range and improving full-range acoustic performance. Attached Figure Description
[0016] Figure 1 This is a schematic cross-sectional view of the MEMS loudspeaker shown in an embodiment of this application; Figure 2 This is a schematic diagram of the front structure of the MEMS speaker shown in the embodiment of this application; Figure 3 This is a schematic diagram of the back structure of the MEMS speaker shown in the embodiment of this application; Figure 4 This is a schematic diagram of the front structure of another MEMS loudspeaker as shown in an embodiment of this application; Figure 5 This is a schematic diagram of the rear structure of another MEMS speaker as shown in an embodiment of this application; Figures 6-1 to 6-3 This is a schematic diagram showing the deformation of the diaphragm layer as a function of frequency, as illustrated in the embodiments of this application. Figure 7 This is a schematic diagram showing the maximum value of the deformation of the diaphragm layer as a function of frequency, as illustrated in the embodiments of this application. Figures 8-1 to 8-6 This is a schematic diagram of the sound pressure level generated by the diaphragm layer shown in the embodiments of this application; Figure 9 This is a schematic flowchart illustrating the fabrication method of the piezoelectric MEMS loudspeaker shown in the embodiments of this application; Figure 10This is a schematic diagram illustrating the fabrication process of the piezoelectric MEMS loudspeaker shown in an embodiment of this application. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.
[0018] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”
[0019] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.
[0021] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.
[0022] 1) Micro-Electro-Mechanical Systems Speaker (MEMS) is a type of micro-system that integrates electronic circuits and mechanical structures by using semiconductor technology to fabricate a micro-substrate such as silicon.
[0023] 2) MEMS loudspeakers are miniaturized, highly integrated sound-generating devices manufactured using semiconductor microfabrication technology. Piezoelectric MEMS loudspeakers utilize the deformation of piezoelectric materials under an electric field to drive a diaphragm to produce sound. They are compact in structure and have low power consumption, and are commonly used in portable medical devices, miniature alarms, and other applications.
[0024] In related technologies, piezoelectric MEMS loudspeakers typically use a fully fixed diaphragm. Due to the micron-level physical size of the piezoelectric fully fixed diaphragm, it has a good response to high-frequency signals, but a poor response to low-frequency signals, and a relatively narrow frequency response range.
[0025] In view of this, embodiments of this application provide a full-band piezoelectric MEMS loudspeaker and a method for fabricating a full-band piezoelectric MEMS loudspeaker. The piezoelectric MEMS loudspeaker integrates several vibration units, with different vibration units responding to input signals in different frequency ranges, thus optimizing the response to low-frequency signals and improving the frequency response range.
[0026] Figure 1 This is a cross-sectional schematic diagram of the MEMS loudspeaker shown in an embodiment of this application.
[0027] Figure 2 This is a schematic diagram of the front structure of the MEMS speaker shown in the embodiment of this application.
[0028] Figure 3 This is a schematic diagram of the back structure of the MEMS speaker shown in an embodiment of this application.
[0029] See Figures 1 to 5 The present application provides a full-band piezoelectric MEMS loudspeaker, which includes a support substrate layer and a diaphragm layer distributed along the thickness direction; The diaphragm layer has N vibration units on its plane. The Nth vibration unit is used to generate sound waves in response to the Nth frequency band signal, where N is an integer greater than or equal to 2. The vibration unit includes a first electrode 16, a piezoelectric layer 17, and a second electrode 18 distributed along the thickness direction.
[0030] The supporting base layer has a diaphragm support 21 on the base layer plane. The diaphragm support 21 abuts against the diaphragm layer and is used to isolate N vibration units. The area surrounded by the diaphragm support forms a back cavity 22.
[0031] In this embodiment, a plurality of vibration units are integrated on a diaphragm layer of a MEMS loudspeaker. Each vibration unit responds to input signals of different frequency bands and generates sound by vibrating in different frequency bands. When a voltage is applied to the MEMS loudspeaker, the vibration units adapted to different resonant frequencies respond to low, mid, and high frequency acoustic signals respectively, achieving sound pressure superposition within the audible frequency range and improving the full-band acoustic performance.
[0032] In one embodiment, the diaphragm layer plane includes a central region and an outer edge region, and the diaphragm layer is provided with a first vibration unit and a plurality of second vibration units; the first vibration unit is disposed in the central region and is used to generate high-frequency sound waves in the audible frequency range of the human ear; the plurality of second vibration units are disposed circumferentially in the outer edge region along the central region and are used to generate mid-frequency sound waves and low-frequency sound waves in the audible frequency range of the human ear.
[0033] In one exemplary embodiment, such as Figures 2 to 3 As shown, the diaphragm layer has a first vibration unit 11a and second vibration units 12a to 15a disposed on the plane of the diaphragm layer. The first vibration unit 11a is located in the central region of the plane of the diaphragm layer, and the second vibration units 12a, 13a, 14a, and 15a are distributed circumferentially around the first vibration unit 11a. Each vibration unit is provided with an independent first electrode 16, a piezoelectric layer 17, and a second electrode 18, which respond to input signals of different frequency bands respectively. The first vibration unit 11a is a fully fixed diaphragm, and its edge is fixed to the diaphragm support. The second vibration units are fixed to the diaphragm support only on one side, and the diaphragm support isolates the first vibration unit and the second vibration unit.
[0034] To prevent vibration waves from being transmitted to adjacent vibration units, a first slotted gap 14 is provided between the second vibration units.
[0035] In this exemplary embodiment, the audible frequency range of the human ear can be divided into five corresponding frequency bands, with the first frequency band signal being the lowest frequency band signal and the fifth frequency band signal being the highest frequency band signal. Specifically, vibration unit 11a responds to the first frequency band signal, vibration unit 12a responds to the second frequency band signal, and so on, with vibration unit 15a responding to the fifth frequency band signal.
[0036] Figure 4 This is a schematic diagram of the front structure of another MEMS speaker as shown in an embodiment of this application.
[0037] Figure 5 This is a schematic diagram of the rear structure of another MEMS speaker as shown in an embodiment of this application.
[0038] In another exemplary embodiment, such as Figures 4 to 5As shown, the vibration unit includes a first vibration unit 11b, a second vibration unit 12b, and a third vibration unit 13b. The first vibration unit 11b is disposed in the central region of the diaphragm layer plane and is used to respond to high-frequency drive signals. The second vibration unit 12b and the third vibration unit 13b are disposed circumferentially around the central region of the diaphragm layer. The second vibration unit 12b is used to respond to mid-frequency drive signals, and the third vibration unit 13b is used to respond to the lowest frequency drive signals.
[0039] In this embodiment, the audible frequency range is divided into three bands: low frequency, mid frequency, and high frequency. The first vibration unit 11b is a fully fixed diaphragm with the smallest area, used to respond to high-frequency drive signals and generate high-frequency sound waves. The second vibration unit 12b is a single-sided fixed diaphragm with a medium area, used to respond to mid-frequency drive signals and generate mid-frequency sound waves. The third vibration unit 13b is a single-sided fixed diaphragm with the largest area, used to respond to low-frequency drive signals and generate low-frequency sound waves.
[0040] Preferably, in this embodiment, the first vibration unit 11b is a unit with a radius of 2000. The circle. The length of the first slotted gap 14 between the first vibration unit and the second vibration unit is 2000. , width is 4 The second vibration element 12b contains two symmetrical regions, each with a radius of 4000. and radius 2000 Take the difference set of the concentric circles formed by the semicircles. The region with the included angle. The third vibration element 13b contains two symmetrical regions, each with a radius of 4000. and radius 2000 The semicircle (the whole circle is taken as) Take the difference set of the concentric circles formed by the sector regions. The region of the included sector.
[0041] See Figure 3 and Figure 5 In some embodiments, the diaphragm support is supported on the bottom surface of the diaphragm layer around the edges of the first vibration unit 11a and the first vibration unit 11b.
[0042] See Figures 2 to 5 In some embodiments, a first slotted gap 14 is provided between the second vibration units, and the first slotted gap 14 is used to separate adjacent second vibration units.
[0043] In this embodiment, the narrow slit design of the first slot 14 not only avoids acoustic short circuits, but also optimizes vibration efficiency through diaphragm segmentation, reduces crosstalk, and further improves acoustic performance.
[0044] See Figures 4 to 5 In some embodiments, the first vibration unit 11b is provided with a second slot 15, which divides the first vibration unit 11b, thereby weakening the acoustic short-circuit effect and optimizing the vibration efficiency.
[0045] Preferably, the second slot 15 is within a radius of 2000 mm of the first vibration unit 11b. The central area forms a cross-shaped slit, and the width of the second slot 15 is 4. .
[0046] The following is a test analysis of the MEMS speaker shown in this embodiment.
[0047] Figure 6 is a schematic diagram showing the deformation of the diaphragm layer as a function of frequency in an embodiment of this application; Figure 7 This is a schematic diagram showing the maximum value of the deformation of the diaphragm layer as a function of the characteristic frequency, as illustrated in the embodiments of this application. Figure 8 is a schematic diagram of the sound pressure level generated by the diaphragm layer shown in the embodiment of this application.
[0048] Figure 6-1 This represents the displacement change of the diaphragm center of the first vibration unit 11b when a sweep frequency signal is input. Figure 6-2 This represents the displacement change of the diaphragm center of the second vibration unit 12b when a sweep frequency signal is input. Figure 6-3 This represents the displacement change of the diaphragm center of the third vibration unit 13b when a sweep frequency signal is input. For example... Figures 6-1 to 6-3 As shown, the displacement of the diaphragm center of the three vibration units in the frequency range of 4kHz to 5kHz corresponds to the optimal response at low frequency, mid frequency and high frequency, respectively.
[0049] like Figure 7 As shown in the embodiments of this application, the MEMS loudspeaker generates corresponding peak values in low-frequency, mid-frequency, and high-frequency signal inputs, respectively.
[0050] This application embodiment tests the sound pressure level of the loudspeaker in a swept-frequency signal. In the response to six frequency signals, the sound pressure contour lines on the loudspeaker's diaphragm layer are as follows: Figures 8-1 to 8-6 As shown in the figure, the results show that the speaker can achieve a sound pressure level of 80dB to 110dB in all six frequency signals, which is superior to the full-frequency sound pressure performance of traditional fixed diaphragm speakers.
[0051] To achieve the above objectives, this application also provides a method for fabricating a full-band piezoelectric MEMS loudspeaker, which is used to fabricate the full-band piezoelectric MEMS loudspeaker described in this application.
[0052] Figure 9This is a schematic flowchart illustrating the fabrication method of the piezoelectric MEMS loudspeaker shown in the embodiments of this application.
[0053] See Figure 9 The fabrication method of the piezoelectric MEMS loudspeaker shown in this application embodiment includes the following steps: Step 101: Pre-treat the supporting substrate layer; Step 102: A diaphragm layer is formed on the supporting substrate layer by deposition and photolithography, wherein the diaphragm layer includes N vibration units; Step 103: Etch the back side of the supporting substrate layer to form the diaphragm support and back cavity; Step 104: Encapsulate the supporting substrate layer and the diaphragm layer to obtain a MEMS loudspeaker.
[0054] In some embodiments, the diaphragm layer includes a first vibration unit, a second vibration unit, and a third vibration unit; The process of forming a diaphragm layer on the supporting substrate by deposition and photolithography includes: Step 201: Sequentially deposit an insulating layer, a first electrode layer, and a piezoelectric layer on the front side of the supporting substrate layer; Step 202: Coat the piezoelectric layer with photoresist and transfer the diaphragm pattern through a preset mask. The diaphragm pattern includes a first vibration unit region, a second vibration unit region, and a third vibration unit region. Step 203: Etch the first electrode layer and the piezoelectric layer according to the diaphragm pattern to form the first vibration unit, the second vibration unit and the third vibration unit; Step 204: Deposit a second electrode layer on the etched piezoelectric layer to form a diaphragm layer.
[0055] In some embodiments, etching the back side of the supporting substrate to form a diaphragm support and a back cavity includes: Step 301: Coat the back of the support substrate with photoresist and transfer the cavity pattern through a preset mask; Step 302: Etch the back side of the supporting substrate layer to form a diaphragm support and a back cavity; wherein the back cavity extends through the supporting substrate layer to the insulating layer, and the diaphragm support supports the diaphragm layer around the edge of the first vibration unit.
[0056] In some embodiments, the formation of the diaphragm layer on the supporting substrate layer by deposition and photolithography further includes: A first slot is etched on the second electrode layer, wherein the first slot is disposed between the second vibration unit and the third vibration unit, and the first slot is used to separate the second vibration unit and the third vibration unit.
[0057] In some embodiments, the formation of the diaphragm layer on the supporting substrate layer by deposition and photolithography further includes: A second slot is etched on the second electrode layer, wherein the second slot is located within the first vibration unit.
[0058] The preparation method shown in the embodiments of this application is illustrated below with specific application examples.
[0059] Figure 10 This is a schematic diagram illustrating the fabrication process of the piezoelectric MEMS loudspeaker shown in an embodiment of this application. The fabrication method includes the following steps: Substrate pretreatment: Select a monocrystalline silicon substrate (supporting substrate layer), clean and dry it to remove surface impurities; Thin film deposition: See Figure 10 (a) A 400 nm thick layer was deposited using chemical vapor deposition (CVD). The first electrode was formed by sequentially depositing 20 nm Ti and 200 nm Pt layers using a sputtering process; a sol-gel method was then used to deposit the first electrode. A thick PZT piezoelectric layer is applied and annealed to optimize piezoelectric performance. Patterning: See Figure 10 (b) The PZT piezoelectric layer, the first electrode and the narrow slit are defined by photolithography, and the patterning is completed by reactive ion etching (RIE). Second electrode preparation: See [link / reference] Figure 10 (c) Sputtering deposits of 20 nm Ti and 250 nm Au, followed by a lift-off process to form a second electrode; Back cavity preparation: See Figure 10 (d) Deep reactive ion etching (DRIE) is used to etch the back side of the single-crystal silicon substrate to form the back cavity and diaphragm support, thus completing the chip fabrication; Packaging: Employs wafer-level packaging technology, with acoustic holes in the packaging layer to ensure effective sound wave radiation.
[0060] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.
[0061] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.
[0062] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.
[0063] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.
[0064] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0065] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.
[0066] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
[0067] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0068] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0069] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0070] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.
Claims
1. A full-range piezoelectric MEMS loudspeaker, characterized in that, This includes a supporting substrate layer and a diaphragm layer distributed along the thickness direction; The diaphragm layer has N vibration units disposed on the plane of the diaphragm layer. The Nth vibration unit is used to generate sound waves in response to the Nth frequency band signal, where N is an integer greater than or equal to 2. The vibration unit includes a first electrode, a piezoelectric layer and a second electrode distributed along the thickness direction. The supporting base layer has a diaphragm support on the base layer plane. The diaphragm support abuts against the diaphragm layer and is used to isolate N vibration units. The area surrounded by the diaphragm support forms a back cavity.
2. The piezoelectric MEMS loudspeaker as described in claim 1, characterized in that, The diaphragm layer plane includes a central region and an outer edge region, and the diaphragm layer is provided with a first vibration unit and a plurality of second vibration units; The first vibration unit is disposed in the central region, and the first vibration unit is used to generate high-frequency sound waves in the range of human ear audibility. Several second vibration units are arranged circumferentially along the central region in the outer edge region. The second vibration units are used to generate mid-frequency and low-frequency sound waves in the range of human hearing.
3. The piezoelectric MEMS loudspeaker as described in claim 2, characterized in that, A first slotted gap is provided between adjacent second vibration units, and the first slotted gap is used to separate adjacent second vibration units.
4. The piezoelectric MEMS loudspeaker as described in claim 2, characterized in that, The first vibration unit is provided with a second slotted gap.
5. The piezoelectric MEMS loudspeaker as described in claim 2, characterized in that, The diaphragm support supports the bottom surface of the diaphragm layer around the edge of the first vibration unit.
6. A method for fabricating a full-band piezoelectric MEMS loudspeaker, characterized in that, The method for fabricating the full-band piezoelectric MEMS loudspeaker according to any one of claims 1 to 5 includes: Pre-treatment of the supporting substrate layer; A diaphragm layer is formed on the supporting substrate layer by deposition and photolithography, wherein the diaphragm layer comprises N vibration units; Etching is performed on the back side of the supporting substrate layer to form a diaphragm support and a back cavity; The supporting substrate layer and the diaphragm layer are encapsulated to obtain a MEMS loudspeaker.
7. The preparation method according to claim 6, characterized in that, The diaphragm layer includes a first vibration unit, a second vibration unit, and a third vibration unit; The process of forming a diaphragm layer on the supporting substrate by deposition and photolithography includes: An insulating layer, a first electrode layer, and a piezoelectric layer are sequentially deposited on the front side of the supporting substrate layer. Photoresist is coated on the piezoelectric layer, and a diaphragm pattern is transferred through a preset mask. The diaphragm pattern includes a first vibration unit region, a second vibration unit region, and a third vibration unit region. The first electrode layer and the piezoelectric layer are etched according to the diaphragm pattern to form a first vibration unit, a second vibration unit and a third vibration unit; A second electrode layer is deposited on the etched piezoelectric layer to form a diaphragm layer.
8. The preparation method according to claim 7, characterized in that, The process of forming a diaphragm layer on the supporting substrate by deposition and photolithography further includes: A first slot is etched on the second electrode layer, wherein the first slot is disposed between the second vibration unit and the third vibration unit, and the first slot is used to separate the second vibration unit and the third vibration unit.
9. The preparation method according to claim 7, characterized in that, The process of forming a diaphragm layer on the supporting substrate by deposition and photolithography further includes: A second slot is etched on the second electrode layer, wherein the second slot is located within the first vibration unit.
10. The preparation method according to claim 7, characterized in that, The etching process on the back side of the supporting substrate layer to form a diaphragm support and a back cavity includes: Photoresist is coated on the back side of the supporting substrate layer, and a back cavity pattern is transferred through a preset mask. The back side of the supporting substrate layer is etched to form a diaphragm support and a back cavity; wherein the back cavity extends through the supporting substrate layer to the insulating layer, and the diaphragm support supports the diaphragm layer around the edge of the first vibrating unit.