Ultralow frequency digital sounding chip
By employing a hexagonal structure and cantilever beam design in the MEMS digital sound chip, the problems of stress concentration and deformation at the diaphragm edge in the square design were solved, achieving higher sound pressure level and consistency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-04-07
AI Technical Summary
The pixel-based sound-generating units of existing MEMS digital sound-generating chips generally adopt a square design, which leads to stress concentration at the edge of the diaphragm, making it prone to local deformation and reducing sound pressure uniformity.
The pixel-emitting unit adopts a hexagonal structure and is combined with a cantilever beam design. The cantilever beam wraps around the diaphragm, with the fixed end of the cantilever beam connected to the fixed support area and the free end connected to the diaphragm. The shape of the cantilever beam is similar to the outer periphery of the diaphragm, which increases the effective area of the diaphragm and reduces stress concentration.
The sound pressure level is increased, the stress distribution at the edge of the diaphragm is more uniform, deformation is reduced, and the consistency of sound pressure is improved.
Smart Images
Figure CN121815172A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of digital sound generation chip technology, and in particular to an ultra-low frequency digital sound generation chip. Background Technology
[0002] MEMS digital audio chips are miniaturized audio output devices based on microelectromechanical systems technology. They can directly convert digital signals into sound and feature small size, low power consumption, and high integration.
[0003] The pixel-emitting units of existing MEMS digital sound chips generally adopt a square design, which leads to stress concentration at the edge of the diaphragm. Furthermore, the right-angled structure is prone to local deformation during vibration, reducing the uniformity of sound pressure. Summary of the Invention
[0004] The purpose of this invention is to provide an ultra-low frequency digital sound chip to solve the problem that existing MEMS digital sound chips using square pixel sound units are prone to stress concentration and low sound pressure.
[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an ultra-low frequency digital sound chip, comprising at least a plurality of pixel sound units; The pixel sound-emitting unit has a hexagonal structure; the pixel sound-emitting unit includes at least an electrode layer, a diaphragm layer spaced apart from the electrode layer, and an oxide layer connected between the electrode layer and the diaphragm layer; The diaphragm layer includes a fixed support region, a diaphragm, and a plurality of cantilever beams connecting the fixed support region and the diaphragm. The plurality of cantilever beams are distributed around the outer periphery of the diaphragm, and the fixed ends and free ends of the plurality of cantilever beams are arranged circumferentially along the outer periphery of the diaphragm. The fixed support region is located outside the cantilever beams. The fixed end of each cantilever beam is connected to the fixed support region, and the free end of the cantilever beam is connected to the diaphragm.
[0006] Optionally, the outer periphery of the diaphragm layer is a regular hexagon; along the height direction of the diaphragm layer, a plurality of void structures penetrating the diaphragm layer are formed inside the diaphragm layer; both ends of the void structures are hook-shaped structures; the plurality of void structures are arranged circumferentially around the outer periphery of the diaphragm.
[0007] Optionally, the gap structure includes a first gap and a second gap; a plurality of first gaps are arranged circumferentially around the outer side of the diaphragm, and a plurality of second gaps are arranged circumferentially around the outer side of the first gap; the cantilever beam is formed between the first gap and the second gap; the number of first gaps and second gaps is the same.
[0008] Optionally, the number of the first gap and the second gap is six, and the first gap and the second gap form six cantilever beams; the fixed support ends of the cantilever beams correspond one-to-one with the apex of the diaphragm layer; the hook-shaped structure of the first gap bends toward the center of the diaphragm layer, and the hook-shaped structure of the second gap bends toward the edge of the diaphragm layer.
[0009] Optionally, the number of the first gap and the second gap is six, and the first gap and the second gap form six cantilever beams; the fixed end corresponds one-to-one with the midpoint of the side length of the diaphragm layer, the middle part of the first gap protrudes toward the edge of the diaphragm layer; the hook-shaped structure of the first gap bends toward the center of the diaphragm layer, and the hook-shaped structure of the second gap bends toward the edge of the diaphragm layer.
[0010] Optionally, the pattern formed by the void structure is a centrally symmetrical structure; the number of void structures is six, with adjacent void structures partially staggered, and a cantilever beam formed between the staggered portions of adjacent void structures; the hook-shaped structure at one end of the void structure bends toward the edge of the diaphragm layer, and the hook-shaped structure at the other end of the void structure bends toward the center of the diaphragm layer.
[0011] Optionally, the number of the first gap and the number of the second gap are both three; the pattern formed by the first gap and the second gap is 120 degrees rotationally symmetrical.
[0012] Optionally, the fixed end of the cantilever beam protrudes toward the geometric center of the diaphragm.
[0013] Optionally, the electrode layer has a plurality of electrode holes penetrating the electrode layer along the height direction of the electrode layer; the electrode layer has a plurality of protrusions facing the diaphragm, and there is a gap between the protrusions and the diaphragm; the protrusions and the electrode holes are evenly distributed within the projection of the diaphragm onto the electrode layer; the oxide layer has a regular hexagonal ring structure, and the fixed support area is located in the oxide layer; there is a gap between the diaphragm and the electrode layer.
[0014] Optionally, the pixel sound unit further includes a silicon substrate, and the electrode layer is a structure formed on the surface of the silicon substrate itself; a back cavity is provided on the side of the silicon substrate facing away from the electrode layer, and the electrode hole communicates with the back cavity.
[0015] Compared with existing technologies, the present invention provides an ultra-low frequency digital sound chip, comprising at least multiple pixel sound units; each pixel sound unit has a hexagonal structure; each pixel sound unit includes at least an electrode layer, a diaphragm layer spaced apart from the electrode layer, and an oxide layer connecting the electrode layer and the diaphragm layer; the diaphragm layer includes a fixed support region, a diaphragm, and multiple cantilever beams connecting the fixed support region and the diaphragm, the multiple cantilever beams being distributed around the outer periphery of the diaphragm, and the fixed ends and free ends of the multiple cantilever beams being arranged circumferentially along the outer periphery of the diaphragm, the fixed support region being located around the periphery of the cantilever beams; the fixed end of each cantilever beam is connected to the fixed support region, and the free end of the cantilever beam is connected to the diaphragm. In this application, the cantilever beams surround the diaphragm, and the two ends of the cantilever beams are arranged sequentially along the outer periphery of the diaphragm. The shape and orientation of the cantilever beams are similar to the outer periphery of the diaphragm, which can maximize the effective area of the diaphragm and improve the sound pressure level of the pixel sound unit. Furthermore, the pixel-based sound unit adopts a hexagonal structure, which makes the stress distribution at the edge of the diaphragm more uniform and less prone to deformation. Attached Figure Description
[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of a cascaded pixel sound-generating unit for an ultra-low frequency digital sound-generating chip provided by the present invention; Figure 2 This is a cross-sectional schematic diagram of the pixel sound-emitting unit provided by the present invention; Figure 3 A schematic diagram of the structure of the diaphragm layer with twelve cantilever beams and fixed supports at both ends provided by the present invention; Figure 4 An enlarged view of the upper right corner structure of the diaphragm layer with twelve cantilever beams and fixed ends at both ends, provided for the present invention; Figure 5 This is a schematic diagram of the experimental results obtained from an experiment on a pixel-based sound-generating unit with twelve cantilever beams and fixed supports at both ends. Figure 6 A schematic diagram of the structure of the diaphragm layer with twelve cantilever beams and fixed ends in the middle, provided by the present invention; Figure 7 An enlarged view of the upper right corner structure of the diaphragm layer with twelve cantilever beams and fixed ends in the middle, provided for the present invention; Figure 8 A schematic diagram of the structure of the diaphragm layer with six cantilever beams and central symmetry provided for the present invention; Figure 9An enlarged view of the upper left corner structure of the diaphragm layer with six cantilever beams and central symmetry provided for this invention; Figure 10 A schematic diagram of the experimental results obtained by the present invention for a pixel sound-generating unit with a diaphragm layer having six cantilever beams and central symmetry. Figure 11 A schematic diagram of the structure of the diaphragm layer with six cantilever beams and 120-degree rotational symmetry provided by the present invention; Figure 12 A schematic diagram of the structure of the diaphragm layer with small notches provided by the present invention; Figure 13 This is a schematic diagram of the electrode layer provided by the present invention.
[0017] Figure label: 1-Diaphragm layer, 11-Fixed support area, 12-Cantilever beam, 121-Free end, 122-Fixed end, 13-Diaphragm, 14-Gap structure, 141-First gap, 142-Second gap, 2-Oxide layer, 3-Electrode layer, 31-Protrusion structure, 32-Electrode hole, 4-Substrate, 41-Back cavity. Detailed Implementation
[0018] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.
[0019] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.
[0020] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, 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 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 of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.
[0021] Existing MEMS digital sound-generating chips generally adopt a square pixel sound-generating unit array design. The diaphragm of the square pixel sound-generating unit has uneven stress distribution at the edges, which is prone to deformation. In addition, the right-angled structure is prone to local deformation during vibration, which reduces the uniformity of sound pressure.
[0022] To address the aforementioned problems, this invention provides an ultra-low frequency digital sound chip, which will be described below with reference to the accompanying drawings.
[0023] See Figure 1 This invention provides an ultra-low frequency digital sound chip comprising at least multiple pixel sound units. Each pixel sound unit has a regular hexagonal structure. Compared to other regularly tessellated polygons, the isotropy of the hexagonal structure is closer to that of a circle, resulting in a more uniform stress distribution around the diaphragm and reducing the likelihood of deformation. Multiple pixel sound units are cascaded into an array in a row and column configuration. The digital sound chip can generate sound through this array configuration.
[0024] like Figure 2 As shown, the pixel sound unit includes a substrate 4, an electrode layer 3 disposed on the substrate 4, a diaphragm layer 1 disposed at a distance from the electrode layer 3, and an oxide layer 2 connecting the electrode layer 3 and the diaphragm layer 1; the outer periphery of the diaphragm layer 1, the oxide layer 2 and the electrode layer 3 are all regular hexagons; the electrode layer 3 is a structure formed on the surface of the substrate 4 itself; a back cavity 41 is provided on the side of the substrate 4 facing away from the electrode layer 3.
[0025] Optionally, the substrate can be a silicon substrate.
[0026] Depend on Figure 1 and Figure 2As can be seen from the structure, the cantilever beam of this application wraps around the diaphragm, and the two ends of the cantilever beam are arranged sequentially along the outer periphery of the diaphragm. The shape and orientation of the cantilever beam are similar to the outer periphery of the diaphragm, which can maximize the effective area of the diaphragm, improve the sound pressure level of the pixel sound unit, and thus improve the sound pressure level of the digital sound chip. Furthermore, the pixel sound unit adopts a hexagonal structure, which makes the stress distribution at the edge of the diaphragm more uniform and less prone to deformation.
[0027] See Figures 3-12 The aforementioned diaphragm layer 1 includes a fixed support region 11, a diaphragm 13, and multiple cantilever beams 12 connecting the fixed support region 11 and the diaphragm 13. The multiple cantilever beams 12 are distributed around the outer periphery of the diaphragm, with their fixed ends and free ends arranged circumferentially along the outer periphery of the diaphragm 13. The fixed support region is located outside the cantilever beams. The fixed end of each cantilever beam is connected to the fixed support region, and the free end of the cantilever beam 12 is connected to the diaphragm 13. Along the height direction of the diaphragm layer, multiple void structures penetrating the diaphragm layer 1 are formed within the diaphragm layer 1. Both ends of the void structures are hook-shaped structures. The void structures are obtained by etching the diaphragm layer. The multiple void structures are arranged circumferentially around the outer periphery of the diaphragm 13. The void structures are arranged in a nested or staggered manner to form cantilever beams, or only in a staggered manner. The shape formed by the multiple cantilever beams matches the outer periphery of the diaphragm 13, approximating a regular hexagon, thus increasing the effective area of the diaphragm. Since each void structure has hook-shaped structures at both ends, and the hook-shaped structures have a certain curvature, stress concentration at the edge of the diaphragm layer can be reduced.
[0028] The aforementioned void structure may include two different shapes of void structures or all of the same shape. The enclosed cantilever beams may be 12 or 6. The void structure and the enclosed cantilever beams will be described in detail below.
[0029] When the void structure has two different shapes, as one example, such as Figure 3As shown, the gap structure 14 includes a first gap 141 and a second gap 142; the pattern formed by the first gap 141 and the pattern formed by the second gap 142 are nested and arranged, and the first gap 141 and the second gap 142 are partially staggered. Specifically, multiple first gaps 141 are arranged circumferentially around the outer periphery of the diaphragm 13, and multiple second gaps 142 are arranged circumferentially around the outer periphery of the first gaps 141; the number of first gaps 141 and second gaps 142 is the same, both being six. Six cantilever beams are formed between the gaps 142. The fixed ends 122 of the cantilever beams correspond one-to-one with the apex of the diaphragm layer, that is, the center of the fixed end 122 is located on the line connecting the apex and the center point of the diaphragm layer. The free ends 121 of the cantilever beams correspond to the center of the second gap 142, that is, the center of the free end 121 is located on the line connecting the center point of the second gap 142 and the center point of the diaphragm layer. The hook-shaped structure of the first gap 141 bends towards the center of the diaphragm layer; the hook-shaped structure of the second gap 142 bends towards the edge of the diaphragm layer. The fixed ends 122 of the cantilever beams 12 correspond to the apex, thus maximizing the effective area of the diaphragm.
[0030] like Figure 4 As shown, the first gap includes a first end and a second end with hook-like structures, and a third end connecting the first end and the second end. The connecting structures between the first end and the third end, and between the second end and the third end, are all arc-shaped. To reduce stress, the length of the first end P21 of the first gap is 20 μm-60 μm, the length of the third end P22 of the first gap is 20 μm-60 μm, and the radius R21 of the connecting structure between the first end and the third end is 5 μm-20 μm. The second gap structure includes two hook-like structures and a main structure connecting the two hook-like structures. The radius of the connecting structure between the main structure of the second gap structure and any one of the hook-like structures is 10 μm-70 μm.
[0031] See Figure 5 ,right Figure 3 The pixel-based sound-generating unit underwent optical, electrical, and mechanical testing. Experimental data showed that at an adsorption voltage of 78V, the lower amplitude was 2.6μm, and the upper amplitude was 0.8μm; the adsorption time at 90V was within 5μs, and the release time was 2μs; amplitude consistency was consistent, with an average amplitude of 3.4-3.47μm; and no significant attenuation was observed. Here, adsorption voltage is the voltage driving the diaphragm movement; lower amplitude is the maximum amplitude reached by the diaphragm moving downwards from its equilibrium position; upper amplitude is the maximum amplitude reached by the diaphragm moving upwards from its equilibrium position; adsorption time is the time it takes for the diaphragm to move from its equilibrium position towards the lowest point of the electrode; and release time is the time it takes for the diaphragm to release from the lowest point back to its equilibrium position.
[0032] As another embodiment, such as Figure 6As shown, the void structure 14 includes a first void 141 and a second void 142; the number of first voids 141 and second voids 142 is the same, both being six; the shapes formed by the first voids 141 and the shapes formed by the second voids 142 are nested and arranged, and the first voids 141 and second voids 142 are staggered, forming six cantilever beams. Specifically, multiple first voids 141 are arranged circumferentially around the outer periphery of the diaphragm 13, and multiple second voids 142 are arranged circumferentially around the outer periphery of the first voids 141; a cantilever beam 12 is formed between the first voids 141 and the second voids 142; the fixed ends 122 of the cantilever beam 12 correspond one-to-one with the midpoint of the side length of the diaphragm layer, that is, the center of symmetry of the two closest fixed ends 122 is located on the line connecting the midpoint of the side length of the diaphragm layer and the center point of the diaphragm layer. The middle part of the first void 141 protrudes towards the edge of the diaphragm layer. Figure 6 The effective area of the diaphragm accounts for 75% of the total area of the diaphragm layer, the stress does not exceed 2000 MPa, and the resonant frequency is below 200 kHz. To reduce stress, such as... Figure 7 As shown, the outer cantilever control point P1 of the cantilever beam is set to 48.8 μm. The hook-shaped structure of the second void structure includes a first arc and a second arc connecting the first arc and the main body of the second void structure. The radius of the second arc is set to 106 μm, and the radius of the first arc is set to 2 μm.
[0033] When the void structure has the same shape, as one example, such as Figure 8 As shown, there are six void structures 14, and the shape formed by the void structures 14 is a centrally symmetrical structure, which can improve the second mode shape of the diaphragm and achieve an area utilization rate of 71.3%. The void structures 14 are partially staggered, and a cantilever beam 12 is formed between the staggered parts of the two adjacent void structures 14. The fixed ends 122 and free ends 121 of the cantilever beam 12 are arranged circumferentially along the outer periphery of the diaphragm 13. In this embodiment, six fixed ends are formed, and each of the six fixed ends corresponds to one of the six vertices of the diaphragm layer. That is, the distance between the fixed end and the line connecting the vertex and the center point is within a first preset distance range. The first preset distance range can be set as needed. The hook-shaped structure at one end of the void structure 14 bends toward the edge of the diaphragm layer, and the hook-shaped structure at the other end of the void structure 14 bends toward the center of the diaphragm layer.
[0034] See Figure 9The void structure includes an outer cantilever structure and an inner cantilever structure. The connection between the inner and outer cantilever structures has a protrusion towards the edge of the diaphragm layer. The outer cantilever structure includes a hook-shaped structure that bends towards the edge of the diaphragm layer. The inner cantilever structure includes a hook-shaped structure that bends towards the center of the diaphragm layer and an arc-shaped structure that protrudes towards the center of the diaphragm layer. The radius R31 of the hook-shaped structure in the inner cantilever structure is 4um-20um, the radius R32 of the arc-shaped structure is 50um-200um, and the distance P31 between the two endpoints of the inner cantilever structure is 60um-120um.
[0035] See Figure 10 ,right Figure 8 The pixel-based sound-generating unit underwent optical, electrical, and mechanical testing. Based on the experimental data, the following results were obtained: with a pulse signal frequency of 20kHz and 70% duty cycle, the adsorption voltage was 50-52V, the lower amplitude was 2.52-2.56μm, the upper amplitude was 0.33-0.4μm, the adsorption time at 70V was within 5μs, and the release time was 3-4μs; the amplitude consistency was non-attenuating; and the average amplitude was 3.4-3.47μm.
[0036] As an optional implementation, the multiple void structures of the diaphragm layer form six cantilever beams, with the fixed ends of the cantilever beams corresponding to the three vertices of the diaphragm layer. That is, the distance between the fixed ends and the lines connecting the vertices and center point of the diaphragm lies within a second preset distance range, which can be set as needed. Figure 11 (a)-(d), the void structure includes a first void and a second void, each with three voids; the shapes formed by the first voids and the shapes formed by the second voids are nested and arranged, and the first voids and the second voids are staggered. Specifically, multiple first voids are arranged circumferentially around the outer periphery of the diaphragm, and multiple second voids are arranged circumferentially around the outer periphery of the first voids; a cantilever beam is formed between the first voids and the second voids; the shapes formed by the first voids and the second voids are rotationally symmetrical by 120 degrees. Figure 11 (e) The void structures of the diaphragm layer are all the same in shape and size. There are six void structures. The void structures are staggered. The staggered parts of the void structures form a cantilever beam. The fixed end and free end of the cantilever beam are arranged circumferentially along the outer periphery of the diaphragm. The shape formed by the void structures is 120 degrees rotationally symmetrical.
[0037] As an optional implementation method, see [link to implementation details]. Figure 12The fixed end of the cantilever beam can have a small notch protruding towards the geometric center of the diaphragm. The radius of the notch is about 20 μm, which can reduce stress. The notch is applicable to all the above embodiments, that is, whether the void structure is the same, the void structure includes two different shapes, the total number of void structures is six, or the total number of void structures is twelve, stress can be reduced by setting a small notch at the fixed end. For example, Figure 12 (a) The gap structure 14 includes two different structures: a first gap 141 and a second gap 142. The number of both the first and second gaps is three. The patterns formed by the first gaps and the second gaps are nested and arranged, with the first and second gaps interleaved. Specifically, multiple first gaps are arranged circumferentially around the outer periphery of the diaphragm, and multiple second gaps are arranged circumferentially around the outer periphery of the first gaps. A cantilever beam 12 is formed between the first gaps 141 and the second gaps 142. The fixed end 122 of the cantilever beam 12 has a small notch protruding towards the geometric center of the diaphragm 13. The hook-like structures at both ends of the first gap 141 bend towards the edge of the diaphragm layer. The hook-like structures at both ends of the second gap 142 bend towards the center point of the diaphragm layer; as shown... Figure 12 (b) The gap structures have the same shape and the number of gap structures is six. Two adjacent gap structures 14 are staggered and a cantilever beam 12 is formed between the staggered parts of two adjacent gap structures 14. The fixed end 122 and the free end 121 of the cantilever beam 12 are arranged circumferentially along the outer periphery of the diaphragm 13. The fixed end 122 of the cantilever beam 12 is set with a small notch protruding toward the geometric center of the diaphragm.
[0038] As an alternative approach, this application sets the height of the cantilever beam to 0.5µm-3µm, the width of the cantilever beam to 2µm-20µm, and the length of the cantilever beam to 10µm-100µm. It should be noted that the height of the cantilever beam refers to its thickness along the direction perpendicular to the substrate, and the width of the cantilever beam refers to the distance between the void structures forming the cantilever beam.
[0039] In practical applications, the bending stiffness of a cantilever beam reflects its ability to resist bending deformation. The formula for calculating the bending stiffness is shown in formula (1), and the formula for calculating the frequency is shown in formula (2). (1) (2) in, The elastic modulus of a material is an intrinsic property of the material. For example, the elastic modulus of steel is about 200 GPa, while that of aluminum alloy is about 70 GPa. The difference in value directly affects the final stiffness value. The moment of inertia is the cross-sectional moment, a parameter directly related to the cross-sectional shape of the cantilever beam; for rectangular cross-sections... Circular cross-section ; This refers to the span, or length, of the cantilever beam. This represents the number of cantilever beams. For frequency, To concentrate on quality.
[0040] From formulas (1) and (2), it can be seen that, under the same material conditions, the smaller the number of cantilever beams and the smaller the moment of inertia of the cross section, the smaller the bending stiffness and the smaller the frequency.
[0041] Therefore, through the parameter settings of the cantilever beams described above, it can be seen that the pixel sound-generating unit of this application has a small number of cantilever beams with small size, which enables the digital sound-generating chip to achieve ultra-low frequencies. The ultra-low frequency digital sound-generating chip of this application can be applied in the frequency range of 20K-120KHz.
[0042] See Figure 2 and Figure 13 The electrode layer 3 has multiple electrode holes 32 extending through it along its height. These holes 32 communicate with the back cavity 41 and are used to conduct air, creating a certain degree of damping. Multiple protrusions 31 facing the diaphragm are also present on the electrode layer, with gaps between them. These protrusions 31 provide support for the diaphragm. The protrusions 31 and electrode holes 32 are evenly distributed within the projection of the diaphragm 13 onto the electrode layer 3. The oxide layer 2 has a regular hexagonal ring structure, and the fixed support area 11 is located on the solid structure of the oxide layer 2. There is a gap between the diaphragm 13 and the electrode layer 3. With a fixed electrode hole size, adjusting the number and distribution of the electrode holes affects the damping formed by the gap between the diaphragm and the electrode layer. Different electrode hole distributions affect local damping, and the distribution of electrode holes in the electrode layer needs to be adjusted according to the damping design requirements.
[0043] For example, the aperture of the electrode holes is 4.5 μm, the thickness of the electrode layer is 6 μm-30 μm, the distance between the electrode layer and the cantilever beam is 11 μm, the number of electrode holes is 234 or 246, and the spacing between the electrode holes is 15 μm. The protrusion structure 31 is dome-shaped with a radius of 4 μm and a height of 0.25 μm, and the number of protrusion structures 31 is 50-100.
[0044] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.
[0045] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely exemplary descriptions of the invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include such modifications and modifications.
Claims
1. An ultra-low frequency digital sound chip, characterized in that, It includes at least multiple pixel-based sound-emitting units; The pixel sound-emitting unit has a hexagonal structure; the pixel sound-emitting unit includes at least an electrode layer, a diaphragm layer spaced apart from the electrode layer, and an oxide layer connected between the electrode layer and the diaphragm layer; The diaphragm layer includes a fixed support region, a diaphragm, and a plurality of cantilever beams connecting the fixed support region and the diaphragm. The plurality of cantilever beams are distributed around the outer periphery of the diaphragm, and the fixed ends and free ends of the plurality of cantilever beams are arranged circumferentially along the outer periphery of the diaphragm. The fixed support region is located outside the cantilever beams. The fixed end of each cantilever beam is connected to the fixed support region, and the free end of the cantilever beam is connected to the diaphragm.
2. The ultra-low frequency digital sound chip according to claim 1, characterized in that, The outer periphery of the diaphragm layer is a regular hexagon; along the height direction of the diaphragm layer, a plurality of void structures penetrating the diaphragm layer are formed inside the diaphragm layer; both ends of the void structures are hook-shaped structures; the plurality of void structures are arranged circumferentially around the outer periphery of the diaphragm.
3. The ultra-low frequency digital sound chip according to claim 2, characterized in that, The void structure includes a first void and a second void; a plurality of first voids are arranged circumferentially around the outer side of the diaphragm, and a plurality of second voids are arranged circumferentially around the outer side of the first void; the cantilever beam is formed between the first void and the second void; the number of first voids and second voids is the same.
4. The ultra-low frequency digital sound chip according to claim 3, characterized in that, The number of the first gap and the second gap is six, and the first gap and the second gap form six cantilever beams; the fixed support ends of the cantilever beams correspond one-to-one with the apex of the diaphragm layer; the hook-shaped structure of the first gap bends toward the center of the diaphragm layer, and the hook-shaped structure of the second gap bends toward the edge of the diaphragm layer.
5. The ultra-low frequency digital sound chip according to claim 3, characterized in that, The number of the first gap and the second gap is six, forming six cantilever beams; the fixed support ends correspond one-to-one with the midpoint of the side length of the diaphragm layer, the middle part of the first gap protrudes toward the edge of the diaphragm layer; the hook-shaped structure of the first gap bends toward the center of the diaphragm layer, and the hook-shaped structure of the second gap bends toward the edge of the diaphragm layer.
6. The ultra-low frequency digital sound chip according to claim 2, characterized in that, The shape formed by the void structure is a centrally symmetrical structure; there are six void structures, with adjacent void structures partially staggered, and a cantilever beam is formed between the staggered portions of adjacent void structures; the hook-shaped structure at one end of the void structure bends toward the edge of the diaphragm layer, and the hook-shaped structure at the other end of the void structure bends toward the center of the diaphragm layer.
7. The ultra-low frequency digital sound chip according to claim 3, characterized in that, The number of the first gap and the number of the second gap are both three; the pattern formed by the first gap and the second gap is 120 degrees rotationally symmetrical.
8. The ultra-low frequency digital sound chip according to claim 6 or claim 3, characterized in that, The fixed end of the cantilever beam protrudes toward the geometric center of the diaphragm.
9. The ultra-low frequency digital sound chip according to claim 1, characterized in that, The electrode layer has multiple electrode holes that penetrate the electrode layer along its height direction; the electrode layer has multiple protrusions facing the diaphragm, and there is a gap between the protrusions and the diaphragm; the protrusions and the electrode holes are evenly distributed within the projection of the diaphragm onto the electrode layer; the oxide layer has a regular hexagonal ring structure, and the fixed support area is located in the oxide layer; there is a gap between the diaphragm and the electrode layer.
10. The ultra-low frequency digital sound chip according to claim 9, characterized in that, The pixel sound unit also includes a silicon substrate, and the electrode layer is a structure formed on the surface of the silicon substrate itself; a back cavity is provided on the side of the silicon substrate opposite to the electrode layer, and the electrode hole communicates with the back cavity.