A directional MEMS loudspeaker array and its fabrication method

Abstract

This invention discloses a directional MEMS loudspeaker array and its fabrication method. The array includes: a substrate, which comprises multiple columnar support feet, support beams, and a diaphragm arranged in an array; each columnar support foot is connected to its adjacent columnar support feet via support beams; a diaphragm is disposed between the three support beams of every three adjacent columnar support feet arranged in a triangle, the diaphragm not contacting the support beams, and the diaphragm being connected to the three adjacent columnar support feet arranged in a triangle; a piezoelectric unit is disposed on the surface of each diaphragm, the piezoelectric unit comprising a first electrode, a piezoelectric thin film layer, and a second electrode stacked sequentially, the first electrode being disposed on the side of the piezoelectric thin film layer adjacent to the substrate. The directional MEMS loudspeaker array provided by this invention has a small size, and the size and array arrangement involved allow the emitted ultrasonic waves to spontaneously interfere, exhibiting high directivity.

Description

Technical Field

[0001] This invention relates to the technical field of directional loudspeakers, and more particularly to a directional MEMS loudspeaker array and its fabrication method. Background Technology

[0002] Currently, directional micro-electro-mechanical system (MEMS) loudspeaker systems are mainly used in outdoor scenarios such as square dancing and large indoor spaces such as bank lobbies and exhibition halls. However, the requirements for miniaturized application scenarios are gradually increasing, such as bank ATM booths and car interiors.

[0003] However, traditional ultrasonic probes are usually large in size, and their packaging and pins require additional custom printed circuit boards (PCBs) to be arrayed. This results in a large overall size and requires manual assembly, making manufacturing cumbersome. Summary of the Invention

[0004] This invention provides a directional MEMS loudspeaker array and its fabrication method. By adjusting the size and diaphragm thickness of a single ultrasonic transmitting unit, the same frequency as a traditional ultrasonic probe can be achieved. Furthermore, the small size of the loudspeaker and the array arrangement involved enable the emitted ultrasonic waves to spontaneously interfere, resulting in high directivity.

[0005] In a first aspect, embodiments of the present invention provide a directional MEMS loudspeaker array, comprising:

[0006] The substrate includes a plurality of columnar support feet, support beams and diaphragms arranged in an array;

[0007] Each of the columnar support feet is connected to the adjacent columnar support feet by a support beam. A diaphragm is provided between the three support beams of each of the three adjacent columnar support feet arranged in a triangle. The diaphragm is not in contact with the support beams, and the diaphragm is connected to the three adjacent columnar support feet arranged in a triangle respectively.

[0008] Each of the diaphragm surfaces is provided with a piezoelectric unit, the piezoelectric unit comprising a first electrode, a piezoelectric thin film layer and a second electrode stacked sequentially, the first electrode being disposed on the side of the piezoelectric thin film layer adjacent to the substrate.

[0009] Optionally, the surfaces of the support beam and the diaphragm adjacent to the piezoelectric unit are flush with the surfaces of the columnar support feet adjacent to the piezoelectric unit.

[0010] Optionally, the width of the gap between the support beam and the diaphragm is greater than or equal to 25 micrometers and less than or equal to 225 micrometers.

[0011] Optionally, the support beam has the same thickness as the diaphragm.

[0012] Optionally, the columnar support feet can be cylindrical.

[0013] Optionally, the diameter of the columnar support foot is 2000 micrometers, and the height ranges from greater than or equal to 350 micrometers to less than or equal to 725 micrometers;

[0014] The width of the support beam is greater than or equal to 50 micrometers and less than or equal to 450 micrometers.

[0015] Optionally, the distance between two adjacent diaphragms is 500 micrometers;

[0016] The diaphragm is 50 micrometers thick.

[0017] Optionally, the line connecting the geometric centers of three adjacent columnar support feet arranged in a triangle is an equilateral triangle.

[0018] Optionally, the side length of the equilateral triangle is 4330 micrometers.

[0019] Secondly, embodiments of the present invention provide a method for fabricating a directional MEMS loudspeaker array, comprising:

[0020] Provide a substrate;

[0021] A first electrode material layer and a piezoelectric material layer are sequentially formed on the first surface of the substrate;

[0022] The first electrode material layer and the piezoelectric material layer are patterned to form a plurality of first electrodes and a plurality of piezoelectric thin film layers;

[0023] A second electrode is formed on the surface of the first electrode and the piezoelectric thin film layer, forming a plurality of piezoelectric units, wherein each piezoelectric unit includes a first electrode, a piezoelectric thin film layer and a second electrode stacked sequentially.

[0024] The first surface of the substrate is etched to remove a portion of the substrate at a predetermined location;

[0025] The second surface of the substrate is etched to remove all the substrate at the preset position and thin the substrate in some other areas, forming a substrate including multiple arrayed columnar support feet, support beams and diaphragms; wherein each of the adjacent columnar support feet is connected to the adjacent columnar support feet through support beams, and a diaphragm is disposed between the three support beams of every three adjacent columnar support feet arranged in a triangle, the diaphragm is not in contact with the support beams, the diaphragm is connected to the three adjacent columnar support feet arranged in a triangle respectively, and a piezoelectric unit is disposed on the surface of each diaphragm.

[0026] In the technical solution provided in this embodiment of the invention, each columnar support foot is connected to its adjacent columnar support foot via a support beam. A diaphragm is disposed between the three support beams of every three adjacent columnar support feet arranged in a triangle. The diaphragm does not contact the support beams, and is connected to the three adjacent columnar support feet arranged in a triangle. This arrangement allows the directional MEMS speaker array to be tightly packed, resulting in a smaller size compared to traditional ultrasonic probe arrays. Each diaphragm surface is provided with a piezoelectric unit, which includes a first electrode, a piezoelectric thin film layer, and a second electrode stacked sequentially. The first electrode is disposed on the side of the piezoelectric thin film layer adjacent to the substrate. By inputting an alternating voltage into the first and second electrodes, the piezoelectric unit drives the diaphragm to vibrate. The directional MEMS speaker array designed in this embodiment of the invention is small in size, and through the array arrangement of the columnar support feet, support beams, piezoelectric units, and diaphragms, the emitted ultrasonic waves interfere in a specified direction, thus possessing directivity. The MEMS loudspeaker array of this invention addresses the shortcomings of traditional arrays, achieving similar sound pressure levels while having a smaller size. Furthermore, it is manufactured using MEMS technology in a single step, eliminating the need for additional assembly. By adjusting the size of individual ultrasonic transmitting units and the diaphragm thickness, the same frequency as traditional ultrasonic probes can be achieved. Therefore, it can replace current transmitting array modules using the driving circuitry of traditional array systems.

[0027] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a line drawing of a directional MEMS loudspeaker array provided in an embodiment of the present invention;

[0030] Figure 2 This is a perspective view of a directional MEMS loudspeaker array provided in an embodiment of the present invention;

[0031] Figure 3 This is a partially enlarged view of a directional MEMS loudspeaker array provided in an embodiment of the present invention;

[0032] Figure 4 yes Figure 3 A cross-sectional view of a directional MEMS loudspeaker array along section line AA;

[0033] Figure 5 This is a dimensional diagram of a directional MEMS loudspeaker array provided in an embodiment of the present invention;

[0034] Figure 6 This is a schematic flowchart of a method for fabricating a directional MEMS loudspeaker array according to an embodiment of the present invention;

[0035] Figures 7-27 This is a schematic diagram of the structure corresponding to each step of the fabrication method of a directional MEMS loudspeaker array provided in an embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention 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 the invention 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 a 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.

[0038] Figure 1 This is a line drawing of a directional MEMS loudspeaker array provided in an embodiment of the present invention; Figure 2 This is a perspective view of a directional MEMS loudspeaker array provided in an embodiment of the present invention. Figure 3 This is a partially enlarged view of a directional MEMS loudspeaker array provided in an embodiment of the present invention. Figure 4 yes Figure 3 A cross-sectional view of the directional MEMS loudspeaker array along section line AA, see [reference]. Figures 1-4The directional MEMS loudspeaker array includes: a substrate 30, which includes multiple columnar support feet 10, support beams 11, and diaphragms 1 arranged in an array; each columnar support foot 10 is connected to its adjacent columnar support foot 10 through a support beam 11, and a diaphragm 1 is disposed between the three support beams 11 of every three adjacent columnar support feet 10 arranged in a triangle, the diaphragm 1 and the support beams 11 are not in contact with each other, and the diaphragm 1 is connected to the three adjacent columnar support feet 10 arranged in a triangle respectively; a piezoelectric unit is disposed on the surface of each diaphragm 1, the piezoelectric unit includes a first electrode 2, a piezoelectric thin film layer 3 and a second electrode 6 stacked in sequence, the first electrode 2 being disposed on the side of the piezoelectric thin film layer 3 adjacent to the substrate.

[0039] In this design, a diaphragm 1 and a piezoelectric unit 31 constitute a transmitting unit, which is used to emit ultrasonic waves. The substrate 30 can be a silicon substrate. The piezoelectric thin film layer 3 can be made of lead zirconate titanate, and the thickness of the piezoelectric thin film layer is 2 micrometers. The first electrode 2 and the second electrode 6 can be copper electrodes, and the thickness of both the first electrode and the second electrode is 0.2 micrometers.

[0040] Specifically, an alternating voltage is input in the vertical direction of the first electrode 6 and the second electrode 2, and an electromagnetic field is generated in the horizontal direction to stretch and contract the piezoelectric film 3 in the horizontal direction, thereby driving the diaphragm 1 to vibrate. The generated ultrasonic waves can interfere with each other. Due to the thickness of the diaphragm 1, the size of the columnar support foot 10 and the support beam 11, the ultrasonic waves generated by each diaphragm 1 have the same frequency in the specified direction, while the ultrasonic waves generated in other directions have different phases and frequencies. This causes the generated ultrasonic waves to superimpose in the specified direction and cancel out in other directions.

[0041] In the technical solution provided in the embodiments of the present invention, each columnar support foot 10 is connected to its adjacent columnar support foot 10 through a support beam 11. A diaphragm 1 is disposed between the three support beams 11 of every three adjacent columnar support feet 10 arranged in a triangle. The diaphragm 1 and the support beam 11 do not contact each other, and the diaphragm 1 is connected to the three adjacent columnar support feet 10 arranged in a triangle. This arrangement allows the directional MEMS speaker array to be tightly arranged, resulting in a smaller size compared to traditional ultrasonic probe arrays. A piezoelectric unit 31 is disposed on the surface of each diaphragm 1. The piezoelectric unit 31 includes a first electrode 2, a piezoelectric thin film layer 3, and a second electrode 6 stacked sequentially. The first electrode 2 is disposed on the side of the piezoelectric thin film layer 3 adjacent to the substrate. By inputting alternating voltage into the first electrode 2 and the second electrode 6, the piezoelectric unit 31 drives the diaphragm 1 to vibrate. The directional MEMS loudspeaker array designed in this embodiment of the invention is small in size, and through the array arrangement of the columnar support foot 10, support beam 11, piezoelectric unit 31, and diaphragm 1, the emitted ultrasonic waves interfere in a specified direction, thus possessing directivity. The MEMS loudspeaker array of this embodiment of the invention can overcome the shortcomings of traditional arrays, achieving a similar emitted sound pressure level while having a smaller size, and is manufactured in one step using MEMS technology without additional assembly operations. By adjusting the size of a single ultrasonic transmitting unit and the diaphragm thickness, the same frequency as a traditional ultrasonic probe can be achieved, thus allowing the use of the driving circuit of a traditional array system to replace the current transmitting array module.

[0042] See Figure 4 Based on the above embodiments, optionally, the surfaces of the support beam 11 and the diaphragm 1 adjacent to the piezoelectric unit 31 are flush with the surfaces of the columnar support foot 10 adjacent to the piezoelectric unit 31.

[0043] In this embodiment of the invention, the surfaces of the support beam 11 and the diaphragm 1 adjacent to the piezoelectric unit 31 are flush with the surfaces of the columnar support foot 10 adjacent to the piezoelectric unit 31, making it easier to fabricate the piezoelectric unit 31 on the upper surfaces of the support beam 11, the diaphragm 1, and the columnar support foot 10.

[0044] See Figure 4 Based on the above embodiments, optionally, the width of the gap between the support beam 11 and the diaphragm 1 is greater than or equal to 25 micrometers and less than or equal to 225 micrometers. In this embodiment of the invention, by setting the width of the gap between the support beam 11 and the diaphragm 1 to be greater than or equal to 25 micrometers and less than or equal to 225 micrometers, not only can the support beam 11 and the diaphragm 1 be made easier to manufacture, but the generated ultrasonic waves can also have high directivity.

[0045] See also Figure 4Optionally, based on the above embodiments, the support beam 11 has the same thickness as the diaphragm 1.

[0046] In this embodiment of the invention, by setting the support beam 11 and the diaphragm 1 to have the same thickness, the support beam 11 and the diaphragm 1 can be formed by the same etching process, reducing the number of process steps.

[0047] See also Figure 4 Optionally, based on the above embodiments, the columnar support foot 10 can be cylindrical.

[0048] Specifically, the cylindrical column support foot 10 is connected to each support beam 11 and diaphragm 1 in the same way, and the support force on each support beam 11 and diaphragm 1 is the same, so as to avoid the vibration of the diaphragm due to inconsistent support force, which would cause the ultrasonic frequency emitted by some transmitting units to not meet the requirements.

[0049] Figure 5 This is a dimensional diagram of a directional MEMS loudspeaker array provided in an embodiment of the present invention. See also... Figure 5 Based on the above embodiments, optionally, the diameter of the columnar support foot 10 is 2000 micrometers, and the height ranges from greater than or equal to 350 micrometers to less than or equal to 725 micrometers. The width of the support beam 11 is greater than or equal to 50 micrometers and less than or equal to 450 micrometers.

[0050] Where c represents the diameter of the column base 10, d represents the height of the column base 10, and e represents the width of the support beam 11.

[0051] In this embodiment of the invention, by setting the diameter c of the columnar support foot 10 to 2000 micrometers and the height d to be greater than or equal to 350 micrometers and less than or equal to 725 micrometers, and the width e of the support beam 11 to be greater than or equal to 50 micrometers and less than or equal to 450 micrometers, the generated ultrasonic waves can interfere in a specified direction, exhibiting high directivity.

[0052] See also Figure 5 Based on the above embodiments, optionally, the distance between two adjacent diaphragms is 500 micrometers; the thickness of the diaphragm is 50 micrometers.

[0053] Where b represents the distance between two adjacent diaphragms, and f represents the diaphragm thickness. Both the diaphragm thickness and the support beam thickness are 50 micrometers. This configuration makes the diaphragm easier to manufacture and allows for a wider range of adjustable vibration frequencies.

[0054] See also Figure 5 Based on the above embodiments, optionally, the line connecting the geometric centers of three adjacent columnar support feet 10 arranged in a triangle is an equilateral triangle.

[0055] In this embodiment of the invention, the directional MEMS loudspeaker array is arranged in such a way that the line connecting the geometric centers of three adjacent columnar support feet 10 arranged in a triangular pattern forms an equilateral triangle. This makes the various transmitting units in the directional MEMS loudspeaker array more compact, the MEMS loudspeaker array smaller in size, and also enables the directional MEMS loudspeaker array to have high directivity.

[0056] See also Figure 5 Based on the above embodiments, optionally, the side length of the equilateral triangle is 4330 micrometers.

[0057] Where 'a' represents the side length of the equilateral triangle. In this embodiment of the invention, by setting the side length of the equilateral triangle to 4330, the ultrasonic waves generated by the diaphragm vibration have the same frequency, amplitude, and phase in the specified direction, achieving precise directional sound generation with high directivity.

[0058] Figure 6 This is a schematic flowchart of a method for fabricating a directional MEMS loudspeaker array provided in an embodiment of the present invention. Figures 7-27 This is a schematic diagram illustrating the structural steps of a method for fabricating a directional MEMS loudspeaker array according to an embodiment of the present invention. See also... Figure 6 The method for fabricating this directional MEMS loudspeaker array includes:

[0059] S110, Provide a substrate.

[0060] See Figure 7 A substrate 30 is provided, which may be a silicon substrate.

[0061] S120, A first electrode material layer and a piezoelectric material layer are sequentially formed on the first surface of the substrate.

[0062] For details, see Figure 8 A first electrode material layer 2 is formed on the first surface of the substrate 30 using a magnetron radio frequency sputtering process, and a piezoelectric material layer 3 is formed on the side of the first electrode material layer 2 away from the first surface of the substrate 1 using a magnetron radio frequency sputtering process.

[0063] S130. Pattern the first electrode material layer and the piezoelectric material layer to form multiple first electrodes and multiple piezoelectric thin film layers.

[0064] For details, see Figure 9 A first photoresist layer 4 is formed on the side of the piezoelectric material layer 3 away from the first surface of the substrate 1 using a spin coating process, see [link to previous section]. Figures 10-11 ,use Figure 11 The first photomask shown is used to form the first photoresist layer through exposure and development techniques. (See Figure 4) Figure 12Then, an etching process is used to form a first trench 20 and a second trench 21 on the piezoelectric material layer 3. The first trench 20 and the second trench 21 correspond to the gaps in the first photomask. See also Figure 13 Remove the first photoresist layer and form the first electrode 2 and the piezoelectric thin film 3 on the first surface of the substrate 30.

[0065] S140. A second electrode is formed on the surface of the first electrode and the piezoelectric thin film layer, forming a plurality of piezoelectric units, wherein each piezoelectric unit includes a first electrode, a piezoelectric thin film layer and a second electrode arranged in sequence.

[0066] For details, see Figure 14 A second photoresist layer 5 is formed on the piezoelectric thin film layer by spin coating process, see [link to documentation]. Figures 15-16 ,use Figure 16 The second photomask is shown, and a patterned second photoresist layer 5 is formed using photolithography and development techniques. See [reference needed]. Figure 17 The second electrode 6 is formed between the second photoresist layer 5 and the piezoelectric material layer 3 using a magnetron radio frequency sputtering process. (See also...) Figure 18 After removing the second photoresist layer 5, a second electrode 6 is formed on the surface of the first electrode 2 and the piezoelectric thin film layer 3, forming multiple piezoelectric units.

[0067] S150: Etch the first surface of the substrate to remove a portion of the substrate at a preset location.

[0068] For details, see Figure 19 A third photoresist layer 7 is formed on the surfaces of the first electrode 2, the piezoelectric thin film layer 3, and the second electrode 6 using a spin coating process, see [link to documentation]. Figures 20-21 ,use Figure 21 The third photomask shown is used to form a patterned third photoresist layer 7 through photolithography and development processes. See also Figure 22 The first surface of the substrate 30 is etched by an etching process to remove a portion of the substrate 30 at a predetermined location.

[0069] S160. The second surface of the substrate is etched so that all the substrate at the preset position is removed and the substrate in some other areas is thinned to form a substrate including multiple arrayed columnar support feet, support beams and diaphragms.

[0070] Each adjacent columnar support foot is connected to the adjacent columnar support foot by a support beam. A diaphragm is provided between the three support beams of each of the three adjacent columnar support feet arranged in a triangle. The diaphragm and the support beam do not contact each other. The diaphragm is connected to the three adjacent columnar support feet arranged in a triangle. A piezoelectric unit is provided on the surface of each diaphragm.

[0071] For details, see Figure 23The second surface of substrate 30 is polished using a polishing process, reducing the thickness of substrate 1 from 750 micrometers to 350 micrometers. See [link to relevant documentation]. Figure 24 A fourth photoresist layer 8 is formed on the second surface of the polished substrate 30 using a spin-coating process, see [link to documentation]. Figures 25-26 ,use Figure 26 The fourth photomask shown is used to pattern the fourth photoresist layer 8 using photolithography and development techniques. See [link to photomask]. Figure 27 The second surface of the substrate 30 is etched by an etching process, which thins the substrate 30 in some other areas and removes all the substrate 30 in the preset position, forming a substrate including multiple arrayed columnar support feet 10, support beams 11 and diaphragm 1. Figure 26 Corresponding to the middle and back cavity Figure 27 The portion of the second surface of the middle substrate 30 that is removed.

[0072] In the technical solution provided in the embodiments of the present invention, a substrate 30 is provided. A first electrode material layer 2 and a piezoelectric material layer 3 are sequentially formed on the first surface of the substrate 30. The first electrode material layer 2 and the piezoelectric material layer 3 are patterned to form multiple first electrodes 2 and multiple piezoelectric thin film layers 3. A second electrode 6 is formed on the surface of the first electrode 2 and the piezoelectric thin film layer 3, forming multiple piezoelectric units. Each piezoelectric unit includes a first electrode 2, a piezoelectric thin film layer 3, and a second electrode 6 sequentially stacked. The first surface of the substrate 30 is etched to remove a portion of the substrate 30 at a predetermined position. The second surface of the substrate 30 is etched to remove all of the substrate 30 at the predetermined position, and the substrate 30 in some other areas is thinned to form a substrate 30 including multiple arrayed columnar support feet 10, support beams 11, and a diaphragm 1. The fabrication method in the embodiments of the present invention is simple, low-cost, and based on silicon MEMS technology, it can be integrated with various small and micro systems.

[0073] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0074] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A directional MEMS loudspeaker array, characterized in that, include: The substrate includes a plurality of columnar support feet, support beams and diaphragms arranged in an array; Each of the columnar support feet is connected to the adjacent columnar support feet by a support beam. A diaphragm is provided between the three support beams of each of the three adjacent columnar support feet arranged in a triangle. The diaphragm is not in contact with the support beams, and the diaphragm is connected to the three adjacent columnar support feet arranged in a triangle respectively. Each of the diaphragm surfaces is provided with a piezoelectric unit, the piezoelectric unit comprising a first electrode, a piezoelectric thin film layer and a second electrode stacked sequentially, the first electrode being disposed on the side of the piezoelectric thin film layer adjacent to the substrate.

2. The directional MEMS loudspeaker array according to claim 1, characterized in that: The surfaces of the support beam and the diaphragm adjacent to the piezoelectric unit are flush with the surfaces of the columnar support feet adjacent to the piezoelectric unit.

3. The directional MEMS loudspeaker array according to claim 1, characterized in that: The width of the gap between the support beam and the diaphragm is greater than or equal to 25 micrometers and less than or equal to 225 micrometers.

4. The directional MEMS loudspeaker array according to claim 1, characterized in that: The support beam has the same thickness as the diaphragm.

5. The directional MEMS loudspeaker array according to claim 1, characterized in that: The columnar support foot is cylindrical.

6. The directional MEMS loudspeaker array according to claim 5, characterized in that: The diameter of the columnar support foot is 2000 micrometers, and the height ranges from greater than or equal to 350 micrometers to less than or equal to 725 micrometers. The width of the support beam is greater than or equal to 50 micrometers and less than or equal to 450 micrometers.

7. The directional MEMS loudspeaker array according to claim 1, characterized in that: The distance between two adjacent diaphragms is 500 micrometers; The thickness of the diaphragm is 50 micrometers.

8. The directional MEMS loudspeaker array according to claim 1, characterized in that: The line connecting the geometric centers of the three adjacent columnar support feet arranged in a triangle is an equilateral triangle.

9. The directional MEMS loudspeaker array according to claim 8, characterized in that: The side length of the equilateral triangle is 4330 micrometers.

10. A method for fabricating a directional MEMS loudspeaker array, characterized in that, include: Provide a substrate; A first electrode material layer and a piezoelectric material layer are sequentially formed on the first surface of the substrate; The first electrode material layer and the piezoelectric material layer are patterned to form a plurality of first electrodes and a plurality of piezoelectric thin film layers; A second electrode is formed on the surface of the first electrode and the piezoelectric thin film layer, forming a plurality of piezoelectric units, wherein each piezoelectric unit includes a first electrode, a piezoelectric thin film layer and a second electrode stacked sequentially. The first surface of the substrate is etched to remove a portion of the substrate at a predetermined location; The second surface of the substrate is etched to remove all the substrate at the preset position and thin the substrate in some other areas, forming a substrate including multiple arrayed columnar support feet, support beams and diaphragms; wherein each columnar support foot is connected to the adjacent columnar support foot through a support beam, and a diaphragm is disposed between the three support beams of every three adjacent columnar support feet arranged in a triangle, the diaphragm is not in contact with the support beams, the diaphragm is connected to the three adjacent columnar support feet arranged in a triangle, and a piezoelectric unit is disposed on the surface of each diaphragm.

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