Pressure sensor and manufacturing method therefor

Abstract

One or more embodiments of the present description relate to a pressure sensor, comprising: a capacitor formed by a first electrode, a second electrode, and a dielectric layer arranged opposite to the first electrode and the second electrode, a first conductive microstructure configured to be in contact with the dielectric layer being provided on the first electrode, wherein the thickness of the dielectric layer is less than 5 μm. By designing the dielectric layer, the dielectric layer has a small thickness and a high dielectric coefficient, so that the pressure sensor has high sensitivity.

Description

A pressure sensor and its fabrication method Cross-references

[0001] This specification claims priority to international application No. PCT / CN2024 / 131780, filed on November 13, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This specification relates to the field of acoustic technology, and in particular to a pressure sensor and its fabrication method. Background Technology

[0003] Pressure sensors, which convert pressure signals into electrical signals to measure pressure, are widely used in industries such as manufacturing, agriculture, and medicine. Building on this foundation, the rise of consumer electronics and the development of human-computer interaction technologies have placed higher demands on the size, sensitivity, accuracy, and linearity of pressure sensors.

[0004] Based on this, it is desirable to propose a pressure sensor with high sensitivity. Summary of the Invention

[0005] This specification provides a pressure sensor comprising a first electrode, a second electrode, and a capacitor formed by a dielectric layer disposed opposite to the second electrode; a first conductive microstructure is disposed on the first electrode and configured to contact the dielectric layer; when the first electrode and the dielectric layer approach each other in response to external pressure, the first conductive microstructure contacts the dielectric layer and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance; the thickness of the dielectric layer is less than 5 μm.

[0006] Another embodiment of this specification provides a method for fabricating a pressure sensor, comprising: fabricating a first conductor layer on a first side of a first substrate, the first conductor layer including a first conductor and a second conductor separated from each other; fabricating an elastic conductive microstructure on the first conductor on a side away from the first substrate; fabricating a second conductor layer; forming a dielectric layer on the second conductor layer; and positioning one side of the first substrate with the elastic conductor microstructure opposite to one side of the second substrate with the dielectric layer, such that the second conductor is fixedly connected to a portion of the dielectric layer.

[0007] Another embodiment of this specification provides a method for fabricating a pressure sensor, comprising: fabricating a first conductor layer on a first side of a first substrate, the first conductor layer including a first conductor and a second conductor separated from each other; fabricating an elastic conductive microstructure on the side of the first conductor away from the first substrate; fabricating a second conductor layer; forming dielectric layers on two opposing surfaces of the second conductor layer; fabricating a third conductor layer on a first side of the second substrate; fabricating an elastic conductive microstructure on the side of the third conductor layer away from the second substrate; aligning the first side of the first substrate with the dielectric layer on one surface of the second conductor layer, and aligning the first side of the second substrate with the dielectric layer on the other surface of the second conductor layer, such that a portion of the second conductor and the third conductor layer are fixedly connected. Attached Figure Description

[0008] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0009] Figure 1 is a schematic diagram of the structure of an ionized pressure sensor according to some embodiments of this specification;

[0010] Figure 2 is a schematic diagram of the structure of a pressure sensor according to some embodiments of this specification;

[0011] Figures 3A and 3B are schematic diagrams of the structure of the first conductive microstructure shown in some embodiments according to this specification;

[0012] Figure 4 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0013] Figure 5 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0014] Figure 6 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0015] Figure 7 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0016] Figures 8A-8E are schematic flowcharts illustrating the fabrication method of a pressure sensor according to some embodiments of this specification;

[0017] Figures 9A-9G are schematic flowcharts illustrating methods for fabricating pressure sensors according to other embodiments of this specification. Detailed Implementation

[0018] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0019] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0020] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0021] Pressure sensors are used to convert pressure signals into electrical signals to detect pressure. A traditional capacitive pressure sensor (also known as a flat-plate pressure sensor) is a typical pressure sensor solution. It includes a parallel-plate capacitor. When external pressure is applied to the capacitive pressure sensor, the distance between the electrodes of the parallel-plate capacitor changes, causing a change in the capacitor's capacitance. The resulting electrical signal reflects the presence of external pressure and, more importantly, its magnitude.

[0022] Traditional capacitive pressure sensors, while simple in structure, have relatively low sensitivity. Ionized pressure sensors, as a new type of capacitive pressure sensor, have emerged to address this need.

[0023] Figure 1 is a schematic diagram of the structure of an ionized pressure sensor according to some embodiments of this specification.

[0024] As shown in Figure 1, the ionotropic pressure sensor 100 includes a substrate 111 and a substrate 112 disposed opposite to each other. A support layer 120 and two opposing electrodes (electrode 130 and electrode 140) are disposed between the substrate 111 and the substrate 112. The electrode 130 may include a conductive layer 131 and a gel layer 132 (or may only include the gel layer 132). The substrate (including substrate 111 and substrate 112) may be made of a printed circuit board (PCB), a flexible printed circuit board (FPC), etc. The conductive layer 131 and the electrode 140 may be made of conductors such as metal or conductive silicone. The gel layer 132 is made of ionotropic gel and may have conductive microstructures in contact with the conductive layer 131 and / or the electrode 140.

[0025] Based on the above structure, when external pressure is applied to the ionized pressure sensor 100, the contact area between the surface of the gel layer 132 and the electrode 140 will change, which in turn will cause the capacitance of the ionized capacitor to change. The resulting electrical signal can reflect the existence of external pressure, and even further reflect the magnitude of the external pressure.

[0026] Ionized pressure sensors offer higher sensitivity than traditional capacitive pressure sensors (i.e., parallel-plate pressure sensors), but their design and fabrication complexity is significantly increased, leading to a substantial rise in manufacturing costs. Furthermore, if subjected to excessive pressure, the ionogel within the gel layer of an ionized pressure sensor may be extruded, causing sensing performance failure. Therefore, ionized pressure sensors exhibit lower reliability.

[0027] Based on this, the embodiments of this specification provide a pressure sensor that overcomes the shortcomings of other capacitive pressure sensors, while also having the characteristics of simple structure, high sensitivity, low cost and easy mass production.

[0028] Figure 2 is a structural schematic diagram of a pressure sensor according to some embodiments of this specification.

[0029] As shown in Figure 2, the pressure sensor 200 includes a first capacitor formed by a first electrode 210, a second electrode 220, and a first dielectric layer 230 disposed opposite to both. A first conductive microstructure 210A is disposed on the first electrode 210 and configured to contact the first dielectric layer 230. In this specification, the first conductive microstructure refers to a structure capable of conducting electricity and containing pores (or voids); or, the first conductive microstructure is capable of conducting electricity, and pores (or voids) can be formed between the first conductive microstructure and the dielectric layer (e.g., the first dielectric layer 230). When the first electrode 210 and the first dielectric layer 230 approach each other in response to external pressure, the contact between the first conductive microstructure 210A and the first dielectric layer 230 causes deformation of the first conductive microstructure 210A. This deformation can change the capacitance of the first capacitor and generate a sensing signal that changes with the capacitance.

[0030] It can be understood that, along the thickness direction (or pressure-sensitive direction) of the pressure sensor 200, the area directly opposite the first capacitor is the sensitive area of ​​the pressure sensor 200, as shown in Figure 2. The pressure sensor 200 has a sensitive area P. When external pressure is applied to this sensitive area P, the pressure sensor 200 can accurately identify the external pressure.

[0031] Figures 3A and 3B are schematic diagrams of the structure of a first conductive microstructure according to some embodiments of this specification.

[0032] Referring to Figures 3A and 3B, a pore can be formed between the first conductive microstructure 210A and the dielectric layer (e.g., the first dielectric layer 230). When the sensitive area P of the pressure sensor 200 is subjected to pressure, although the distance between the bottom end of the first electrode 210 and the opposite electrode (e.g., the second electrode 220 shown in Figure 2, or the second part 422 of the second electrode 420 shown in Figure 4, or the third electrode 460, or the third electrode 560 shown in Figure 5, or the third electrode 660 shown in Figure 6) (i.e., the thickness of the first dielectric layer 230) remains unchanged, due to the presence of the first conductive microstructure 210A, the first conductive microstructure 210A deforms, causing changes in the contact area and the equivalent dielectric constant between the first conductive microstructure 210A and the first dielectric layer 230. This results in the pressure sensor 200 having higher sensitivity than traditional variable-pitch pressure sensors.

[0033] The capacitance value of the capacitor (e.g., the first capacitor) inside the pressure sensor 200 can be calculated using the following formulas (1) to (3): C = C1 + C2 (1) Where C is the capacitance of the first capacitor within the pressure sensor 200; C1 is the capacitance generated by the portion of the first conductive microstructure 210A in contact with the first dielectric layer 230; C2 is the capacitance generated by the portion of the first conductive microstructure 210A not in contact with the first dielectric layer 230; t is the thickness of the first dielectric layer 230; ε0 is the absolute dielectric constant; ε r1 ε is the relative permittivity of the first dielectric layer 230; S1 is the contact area between the first conductive microstructure 210A and the first dielectric layer 230; S2 is the area of ​​the portion of the first conductive microstructure 210A that is not in contact with the first dielectric layer 230 (i.e., the sum of the areas at the openings of the pores); r2 d is the overall equivalent dielectric constant of the air in the non-contact portion and the first dielectric layer 230; d is the average distance between the non-contact portion of the first electrode 210 (or the first conductive microstructure 210A) and the opposite electrode (e.g., the second electrode 220 shown in FIG. 2, or the second part 422 of the second electrode 420 shown in FIG. 4, or the third electrode 460, or the third electrode 560 shown in FIG. 5, or the third electrode 660 shown in FIG. 6).

[0034] From the above formulas (1) to (3), it can be seen that C1 is proportional to S1, while C2 is proportional to S2. When the pressure sensor 200 is subjected to external pressure, the first conductive microstructure 210A deforms, S1 increases, causing C1 to increase, but d decreases, and ε r2 Increasing the capacitance of C2 increases the capacitance of C1, and the simultaneous effect of these two factors increases the total capacitance C, thereby giving the pressure sensor 200 extremely high sensitivity. Furthermore, under external pressure, the rate of change of the contact area of ​​the first conductive microstructure 210A is much greater than the rate of change of d; correspondingly, C1 contributes more to the sensitivity than C2. Therefore, when S1 remains constant, the larger the proportion of C1 in the capacitance C of the first capacitor, the higher the sensitivity of the pressure sensor 200. In other words, the smaller the thickness t of the first dielectric layer 230 and the higher the relative permittivity ε... r1 The higher the value, the greater the proportion of C1 in the pressure sensor 200, and the higher the overall sensitivity of the pressure sensor 200.

[0035] Referring to Figures 3A and 3B, in some embodiments, in order to make the first conductive microstructure 210A easily deformable when the sensitive area of ​​the pressure sensor 200 is subjected to pressure, resulting in a large change in the contact area and equivalent dielectric constant between it and the first dielectric layer 230, thereby making the pressure sensor 200 more sensitive, the first conductive microstructure 210A includes a plurality of spaced flexible conductive protrusions (not shown in the figures), and pores are formed between the flexible conductive protrusions (or, pores are formed between the flexible conductive protrusions and the first dielectric layer 230).

[0036] Since the thickness and pore size of the first conductive microstructure 210A can affect the degree of change in the contact area between the first electrode 210 (or the first conductive microstructure 210A) and the first dielectric layer 230 under external pressure, in order to make the pressure sensor 200 have high sensitivity while having a small size to achieve device miniaturization, it is necessary to design the size of the flexible conductive protrusions and pores.

[0037] In some embodiments, the top of the flexible conductive protrusion can be defined as a protrusion of the first conductive microstructure 210A, such as protrusion M shown in FIG. 3A; the bottom of the aperture can be defined as a concave point of the first conductive microstructure 210A, such as concave point N shown in FIG. 3A. The longitudinal distance between protrusion M and concave point N and the lateral distance between adjacent protrusion M and concave point N can represent the size of the flexible conductive protrusion and the aperture. The longitudinal distance between protrusion M and concave point N refers to the distance d1 between protrusion M and concave point N in the thickness direction, and the lateral distance between protrusion M and concave point N refers to the distance d2 between protrusion M and concave point N in the width direction.

[0038] It should be noted that when determining the longitudinal distance between the protrusion M and the concave point N, if the heights of the multiple flexible conductive protrusions of the first conductive microstructure 210A are consistent, then the top of any flexible conductive protrusion can be defined as the protrusion M, and the bottom of any pore can be defined as the concave point N; if the heights of the multiple flexible conductive protrusions of the first conductive microstructure 210A are different, then the top of the highest flexible conductive protrusion can be defined as the protrusion M, and the bottom of the lowest pore can be defined as the concave point N.

[0039] When determining the lateral distance between adjacent protrusions M and concave points N, if the multiple flexible conductive protrusions of the first conductive microstructure 210A are uniformly distributed, then the lateral distance between any two adjacent protrusions M and concave points N can be used as the lateral distance between adjacent protrusions and concave points of the first conductive microstructure 210A. If the multiple flexible conductive protrusions of the first conductive microstructure 210A are not uniformly distributed, then the multiple flexible conductive protrusions and their corresponding adjacent pores can determine the lateral distance between multiple adjacent protrusions M and concave points N, and the average, minimum, or maximum value of the multiple lateral distances can be used as the lateral distance between adjacent protrusions and concave points of the first conductive microstructure 210A.

[0040] In other embodiments, any point on any flexible conductive protrusion can be taken as a protrusion, and any point on an adjacent hole of the flexible conductive protrusion can be taken as a concave point. The lateral distance between the concave point and the protrusion can be regarded as the lateral distance between a pair of adjacent concave points and protrusions.

[0041] In some embodiments, to achieve high sensitivity and small size for device miniaturization, the longitudinal distance d1 between the bump M and the concave point N of the first conductive microstructure 210A is less than 300 μm, and the lateral distance d2 between adjacent bump M and concave point N of the first conductive microstructure 210A is less than 1 mm. In some embodiments, to ensure that the first conductive microstructure 210A can generate sufficient deformation to guarantee the sensitivity range of the pressure sensor 200 to external pressure, the longitudinal distance d1 between the bump M and the concave point N is 1 μm-250 μm, and the lateral distance d2 between adjacent bump M and concave point N is 1 μm-800 μm. In some embodiments, to ensure a large contact area between the first conductive microstructure 210A and the first dielectric layer 230 while providing sufficient deformation space for the first conductive microstructure 210A to guarantee the sensitivity of the pressure sensor 200, the longitudinal distance d1 between the bump M and the concave point N is 10μm-200μm, and the lateral distance d2 between adjacent bump M and concave point N is 10μm-700μm. In some embodiments, the longitudinal distance d1 between the bump M and the concave point N is 100μm-150μm, and the lateral distance d2 between adjacent bump M and concave point N is 100μm-500μm. Through the above dimensional design, while ensuring a large contact area between the first conductive microstructure 210A and the first dielectric layer 230, sufficient deformation space is provided for the first conductive microstructure 210A, thereby enabling the pressure sensor 200 to have high sensitivity.

[0042] In some embodiments of this specification, the first conductive microstructure 210A can achieve variations in the contact area between the first electrode 210 and the first dielectric layer 230. By designing the longitudinal distance d1 between the protrusions M and concave points N of the first conductive microstructure 210A and the lateral distance between adjacent protrusions M and concave points N, the first conductive microstructure 210A can possess both good stability and good deformation capability, thereby enabling the pressure sensor 200 to have high sensitivity.

[0043] The first dielectric layer 230 is used to separate the first electrode 210 from the opposite electrode (e.g., the second electrode 220 shown in FIG. 2, or the second portion 422 of the second electrode 420 shown in FIG. 4, or the third electrode 460, or the third electrode 560 shown in FIG. 5, or the third electrode 660 shown in FIG. 6), thereby forming a capacitor.

[0044] The first dielectric layer 230 is made of an insulating material with a high dielectric constant. In some embodiments, the material of the first dielectric layer 230 may include, but is not limited to, aluminum oxide, titanium dioxide, magnesium oxide, barium titanate, insulating resin, parylene, etc.

[0045] The thinner the first dielectric layer 230, the larger its dielectric constant, and the higher the sensitivity of the pressure sensor 200. Specifically, referring to formulas (1) to (3) mentioned above, reducing the thickness of the first dielectric layer 230 can reduce d, and C2 is inversely proportional to d. Therefore, the thinner the first dielectric layer 230, the larger C2 can be (and thus the larger C). In addition, the relative dielectric constant ε of C1 and the first dielectric layer 230... r1 Proportional to the dielectric constant ε of the first dielectric layer 230 r1 The larger the value, the larger C1 becomes (which also makes C larger). Increasing C can improve the sensitivity of the pressure sensor 200.

[0046] Accordingly, in some embodiments, in order to maintain a high level of sensitivity of the pressure sensor 200 and to make the pressure sensor 200 small in size for ease of use, the thickness of the first dielectric layer 230 is less than 5 μm, and the relative permittivity of the first dielectric layer 230 is greater than 2. Preferably, the thickness of the first dielectric layer 230 is less than 1 μm, and the relative permittivity of the first dielectric layer 230 is greater than 6.

[0047] In some embodiments, the first dielectric layer 230 can be formed by anodizing or physical vapor deposition. The first dielectric layer 230 prepared by anodizing is thinner, resulting in higher sensitivity of the pressure sensor 200. Furthermore, anodizing offers advantages such as process control, high efficiency, and low cost. Physical vapor deposition can also produce a thinner first dielectric layer 230, leading to higher sensitivity of the pressure sensor 200.

[0048] In some embodiments of this specification, the thickness and relative permittivity of the first dielectric layer 230 are designed to improve the sensitivity of the pressure sensor 200. The first dielectric layer 230 is fabricated using a suitable process to meet specific requirements.

[0049] As shown in FIG4, in some embodiments, the pressure sensor 200 further includes a first substrate 240 and a protective layer 250 located around the first capacitor. The first substrate 240 is disposed on one side of the pressure sensor 200 in the thickness direction. Specifically, the first substrate 240 is located outside the first electrode 210. The protective layer 250 is located on the other side of the pressure sensor 200 in the thickness direction.

[0050] The first substrate 240 and the protective layer 250 provide a protective housing for the pressure sensor 200. The first substrate 240 and the protective layer 250 are themselves non-conductive. In some embodiments, the first substrate 240 may be made of a rigid insulating material such as epoxy fiberglass board (Flame Retardant Type 4, FR-4) or ceramic. In some embodiments, the first substrate 240 may also be made of a flexible insulating material such as polyethylene terephthalate (PET), polyimide (PI), polydimethylsiloxane (PDMS), or silicone. In some embodiments, the thickness of the first substrate 240 may be in the range of 1 μm to 500 μm. In some embodiments, the protective layer 250 may have the same or similar material and structure as the first substrate 240.

[0051] In some embodiments, the first electrode 210 includes a first elastic conductor 211, and a first conductive microstructure 210A is disposed on the surface of the first elastic conductor 211. Specifically, the first conductive microstructure 210A may be disposed on the surface of the first elastic conductor 211 facing the first dielectric layer 230.

[0052] In some embodiments, the first conductive microstructure 210A may be an integral structure formed with the first elastic conductor 211, or it may be a separate structure connected to the first elastic conductor 211.

[0053] In some embodiments, the first electrode 210 is a single-layer conductor structure. In this specification, a single-layer structure refers to a structure made of the same material. In this case, the first elastic conductor 211 can constitute the first electrode 210. In some embodiments, the material of the first elastic conductor 211 may include, but is not limited to, conductive silicone, conductive PDMS, or other flexible conductive materials. Based on this, a first conductive microstructure 210A is present on the surface of the first electrode 210, which contacts the first dielectric layer 230. The first conductive microstructure 210A is made of conductive silicone, conductive PDMS, or other flexible conductive materials doped with conductive particles (which is the same material as the first electrode 210). For example, if the first electrode 210 is made of conductive silicone, then the first conductive microstructure 210A is made of conductive silicone doped with conductive particles.

[0054] In some embodiments, the first electrode 210 is a multilayer conductor structure, comprising a first conductor 212 and a first elastic conductor 211 stacked sequentially, the first elastic conductor 211 being located on the side of the first conductor 212 facing the first dielectric layer 230, and the first conductive microstructure 210A being located on the surface of the first elastic conductor 211 on the side facing the first dielectric layer 230.

[0055] In some embodiments, the first conductor 212 is formed of a conductive material. For example, the first conductor 212 may be formed of a metallic element (e.g., aluminum, copper, silver, etc.), an alloy (e.g., aluminum alloy, titanium alloy, etc.), flexible conductive silicone, indium tin oxide (ITO) conductive film, or conductive ink, etc.

[0056] For example, when the first conductor 212 is formed of metal, the first elastic conductor 211 can be bonded to the first conductor 212. As another example, when both the first conductor 212 and the first elastic conductor 211 are formed of conductive silicone, the first conductor 212 and the first elastic conductor 211 can be integrally formed, in which case the first conductor 212 and the first elastic conductor 211 can be considered as a single-layer conductor structure. Yet another example, when the first conductor 212 is conductive ink, the first conductor 212 can be formed directly on the surface of the first elastic conductor 211.

[0057] In some embodiments of this specification, by providing a first conductive microstructure 210A on the first electrode 210 that contacts the first dielectric layer 230, the change in the contact area between the first dielectric layer 230 and the first electrode 210 can be increased, thereby improving the sensitivity of the pressure sensor 200. By designing the first dielectric layer 230 to have a thinner thickness and a higher dielectric constant, the pressure sensor 200 can achieve higher sensitivity.

[0058] In some embodiments, the first electrode and the second electrode serve as the inlet / outlet of a capacitor within the pressure sensor, and the first electrode and the second electrode can be located on opposite sides of the capacitor, respectively. For example, as shown in FIG2, a first capacitor is formed between the first electrode 210 and the second electrode 220, and the first electrode 210 and the second electrode 220 can serve as the inlet and outlet of the first capacitor, respectively, and the first electrode 210 and the second electrode 220 are located on opposite sides of the thickness direction of the first capacitor (for example, the first electrode 210 and the second electrode 220 are located on opposite sides of the first dielectric layer 230 in the thickness direction).

[0059] In some embodiments, the first electrode and the second electrode serve as the input / output terminals of a capacitor within the pressure sensor. The first electrode and the second electrode can be located on the same side of the dielectric layer of the capacitor to facilitate connection to the same circuit board and simplify circuit design. In this case, to form a capacitor within the piezoelectric sensor, the piezoelectric sensor may also include a third electrode (e.g., the third electrode 460 shown in FIG. 4, the third electrode 560 shown in FIG. 5, etc.) disposed on the side of the dielectric layer opposite to the first electrode. A second capacitor is formed between the first electrode and the third electrode.

[0060] In some embodiments, the second electrode and the third electrode, located on opposite sides of the dielectric layer in the thickness direction, can be electrically connected. In this case, a second capacitor is formed between the first electrode and the third electrode, and the third electrode is connected to an external circuit through the second electrode. In this case, the third electrode can be part of the second electrode; please refer to the relevant description in Figure 4 for details.

[0061] In some embodiments, the second electrode and the third electrode located on opposite sides of the dielectric layer in the thickness direction can be insulated from each other. In this case, the third electrode can serve as a floating electrode, and a second capacitor can be formed between the first electrode and the third electrode. A third capacitor can also be formed between the second electrode and the third electrode. Please refer to the relevant description in Figure 5 for details.

[0062] Figure 4 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0063] As shown in Figure 4, the pressure sensor 400 includes a first electrode 410, a second electrode 420, a first dielectric layer 430, a first substrate 440, and a protective layer 450. The first electrode 410 has a first conductive microstructure 410A configured to contact the first dielectric layer 430. The first electrode 410 includes a first elastic conductor 411 and a first conductor 412, and the first conductive microstructure 410A is disposed on the surface of the first elastic conductor 411 facing the first dielectric layer 430. The first electrode 410, the first conductive microstructure 410A, the first substrate 440, and the protective layer 450 are the same as or similar to the first electrode 210, the first conductive microstructure 210A, the first substrate 240, and the protective layer 250 in Figure 2.

[0064] Referring to Figure 4, in some embodiments, the second electrode 420 may include a first portion 421 and a second portion 422. The first portion 421 of the first electrode 410 and the second electrode 420 is disposed on a first side of the first substrate 440 facing the first dielectric layer 430. The second portion 422 of the second electrode 420 is disposed opposite to the first portion 421 and the first electrode 410. The first dielectric layer 430 is disposed on the side of the second portion 422 of the second electrode 420 near the first electrode 410. The first portion 421 and the second portion 422 of the second electrode 420 are electrically connected. Elsewhere in this specification, the second portion 422, which is opposite to the first electrode 410, may also be considered as a third electrode 460. In the configuration of Figure 4, the third electrode 460 is electrically connected to the first portion 421 of the second electrode 420. The first electrode 410, the first dielectric layer 430, and the second portion 422 of the second electrode 420 together form a second capacitor. Furthermore, the second part 422 of the second electrode 420 is electrically connected to the first part 421, thereby transferring the lead-in end / or lead-out end of the second capacitor corresponding to the second electrode 420 to the same side as the first electrode 410, so that the lead-in end and lead-out end of the second capacitor can be directly electrically connected to the same circuit board.

[0065] In some embodiments, the first portion 421 of the second electrode 420 is annular, and the first electrode 410 is located within the annular ring. In some embodiments, the annular ring may include, but is not limited to, a circular ring, a rectangular ring, a triangular ring, a polygonal ring, or an irregular ring. With the above design, while the first electrode 410 and the second electrode 420, which serve as the inlet and outlet of the second capacitor, are disposed on the same side of the second capacitor, mutual interference between the second electrode 420 and the first electrode 410 can be avoided.

[0066] In some embodiments, the first dielectric layer 430 may not be provided between the first portion 421 and the second portion 422 of the second electrode 420. That is, in the width direction, the first dielectric layer 430 is located within the annulus of the first portion 421 of the second electrode 420. In this case, the first portion 421 and the second portion 422 of the second electrode 420 can be directly connected. For example, the first portion 421 and the second portion 422 of the second electrode 420 can be directly bonded together with conductive adhesive (e.g., conductive adhesive layer 423 shown in FIG. 4).

[0067] In some embodiments, a first dielectric layer 430 may also be provided between the first portion 421 and the second portion 422 of the second electrode 420. For example, in the width direction, the distance between the two ends of the first dielectric layer 430 may be the same as or similar to the distance between the two ends of the second portion 422 of the second electrode 420. When the first dielectric layer 430 is provided between the first portion 421 and the second portion 422 of the second electrode 420, in order to electrically connect the first portion 421 and the second portion 422 of the second electrode 420, in some embodiments, a through hole may be provided in the area of ​​the first dielectric layer 430 opposite to the first portion 421 of the second electrode 420, and the first portion 421 and the second portion 422 of the second electrode 420 are fixedly connected by conductive adhesive passing through the through hole, as shown in FIG4.

[0068] In some embodiments, the second portion 422 of the second electrode 420 has a first surface opposite to the first electrode 410, and the second portion 422 of the second electrode 420 also has a second surface opposite to the first portion 421 of the second electrode 420. For example, the outline of the second surface of the second portion 422 of the second electrode 420 is annular, and the first surface of the second portion 422 of the second electrode 420 is located within the annular outline of the second surface. As another example, the second surface of the second portion 422 of the second electrode 420 and the first surface are different regions on the same plane, and the first surface is surrounded by the second surface.

[0069] The first dielectric layer 430 includes a first portion located on a first surface and a second portion located on a second surface. For example, the first portion of the first dielectric layer 430 has an annular outline, and the second portion of the first dielectric layer 430 is located within the annular outline of the first portion of the first dielectric layer 430. It should be noted that, in the width direction, the first portion and the second portion of the first dielectric layer 430 can be disconnected or connected through a third portion of the first dielectric layer 430. The third portion of the first dielectric layer 430 corresponds to the region between the first portion 421 of the second electrode 420 and the first electrode 410 in the width direction.

[0070] In some embodiments, a second portion of the first dielectric layer 430 is provided with a through-hole, and the first portion 421 and the second portion 422 of the second electrode 420 can be fixedly connected by conductive adhesive passing through the through-hole. When the first electrode 410 and the first portion of the first dielectric layer 430 approach each other in response to external pressure, the first conductive microstructure 410A contacts the first portion of the first dielectric layer 430 and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance.

[0071] As shown in Figure 4, a conductive adhesive layer 423 is provided on the side of the first part 421 of the second electrode 420 facing the first dielectric layer 430. The conductive adhesive layer 423 is connected to the first dielectric layer 430, and the side of the conductive adhesive layer 430 facing the first dielectric layer 430 passes through the through hole on the first dielectric layer 430 and is fixedly connected to the second part 422 of the second electrode 420.

[0072] In some embodiments, the first portion 421 of the second electrode 420 may include a second conductor 4211, the second conductor 4211 being located on the side of the first substrate 440 facing the first dielectric layer 430, and the conductive adhesive layer 423 being located on the side of the second conductor 4211 facing the second portion 422 of the second electrode 420.

[0073] In some embodiments, the second conductor 4211 is formed of a conductive material, such as a metallic element (e.g., aluminum, copper, silver, etc.), an alloy (e.g., aluminum alloy, titanium alloy, etc.), or a flexible conductive material (e.g., conductive silicone, etc.). In some embodiments, the second conductor 4211 and the first conductor 412 may be made of the same or different materials.

[0074] In some embodiments, the second conductor 4211 is flush with the first conductor 412, and the first conductor 412 and the second conductor 4211 may belong to the same conductor layer to facilitate processing and reduce the difficulty of the process.

[0075] The conductive adhesive layer 423 includes a main body and conductive adhesive. Specifically, one side of the main body is connected to the second conductor 4211 via conductive adhesive, and the other side of the main body is connected to the first dielectric layer 430 or the second portion 422 of the second electrode 420 via conductive adhesive. The main body of the conductive adhesive layer 423 mainly serves to support and fix the components. The annular main body, the first substrate 440, and the protective layer 450 can form a cavity, which can protect the second capacitor composed of the first electrode 410, the first dielectric layer 430, and the second portion 422 of the second electrode 420.

[0076] In some embodiments, the main body is made of a flexible conductive material (e.g., conductive silicone), so that when the pressure sensor 400 responds to external pressure and the first electrode 410 moves closer to the second electrode 420, the main body can deform, reducing the difficulty for the first electrode 410 and the first dielectric layer 430 to move closer to each other, thereby improving the sensitivity of the pressure sensor 400.

[0077] In some embodiments, the second portion 422 of the second electrode 420 (or the third electrode 460) may include a third conductor 4221. The third conductor 4221 has the same or similar material and structure as the first conductor 212 and / or the second conductor 2211.

[0078] In some embodiments, when the third conductor 4221 is made of a corrosion-resistant metal such as aluminum alloy or titanium alloy, the pressure sensor 400 may not have a protective layer 450.

[0079] In some embodiments, the first portion 421 and the second portion 422 of the second electrode 420 are fixedly connected by a conductive adhesive (e.g., a conductive adhesive layer 423), the melting point of which is lower than that of the first conductive microstructure 410A. Thus, during the hot-pressing process of fabricating the pressure sensor 400, when the conductive adhesive is in a molten state, the first conductive microstructure 410A can remain solid, thereby maintaining its structure and reducing the difficulty of fabrication. On the other hand, when the first dielectric layer 430 has through-holes, during the hot-pressing process of fabricating the pressure sensor 400, when the conductive adhesive is in a molten state, the first conductive microstructure 410A remains solid, preventing it from penetrating into the through-holes and thus avoiding accidental conductive connection between the first electrode 410 and the second portion 422 of the second electrode 420.

[0080] In some embodiments of this specification, the second electrode 420 is designed such that the lead-in and lead-out terminals of the second capacitor formed between the third electrode 460 (or the second portion 422 of the second electrode 420) and the first electrode 410 are on the same side, thereby facilitating connection to the same circuit board and simplifying circuit design. On the other hand, designing the thickness of the first dielectric layer 430 can reduce the difficulty of fabricating vias on the second dielectric layer, making it easier to achieve electrical conductivity between the first portion 421 of the second electrode 420 and the third electrode 460 (or the second portion 422 of the second electrode 420) on both sides of the first dielectric layer 430.

[0081] Figure 5 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0082] As shown in Figure 5, the pressure sensor 400 includes a first electrode 510, a second electrode 520, a first dielectric layer 530, a first substrate 540, and a protective layer 550. The first electrode 510 has a first conductive microstructure 510A configured to contact the first dielectric layer 530. The first electrode 510 includes a first elastic conductor 511 and a first conductor 512, and the first conductive microstructure 510A is disposed on the surface of the first elastic conductor 511 facing the first dielectric layer 530. The second electrode 520 includes a second conductor 5211, which is fixedly connected to the first dielectric layer 530 via a conductive adhesive layer 523. The first electrode 510, the first conductive microstructure 510A, the first substrate 540, and the protective layer 550 are the same as or similar to the first electrode 510, the first conductive microstructure 510A, the first substrate 540, and the protective layer 550 in FIG4. The second electrode 520 (second conductor 5211) is the same as or similar to the first part 421 (second conductor 4211) of the second electrode 420 in FIG4. The conductive adhesive layer 523 is the same as or similar to the conductive adhesive layer 423 in FIG4.

[0083] In some embodiments, the pressure sensor 500 further includes a third electrode 560 disposed on the side of the first dielectric layer 530 opposite to the first electrode 510. The first electrode 510, the first dielectric layer 530, and the third electrode 560 together form a second capacitor. In the configuration shown in FIG5, the third electrode 560 and the second electrode 520 are not electrically connected.

[0084] The third electrode 560 has a first surface opposite to the first electrode 510 and a second surface opposite to the second electrode 520. For example, the second surface of the third electrode 560 has an annular outline, and the first surface of the third electrode 560 is located within the annular outline of the second surface. As shown in FIG5, in some embodiments, the first surface and the second surface of the third electrode 560 are different regions on the same surface of the third electrode 560, with the first surface surrounded by the second surface.

[0085] The first dielectric layer 530 includes a first portion located on a first surface and a second portion located on a second surface. For example, the first portion of the first dielectric layer 530 has an annular outline, and the second portion of the first dielectric layer 530 is located within the annular outline of the first portion of the first dielectric layer 530. The second electrode 520 is in contact with the second portion of the first dielectric layer 530. It should be noted that, in the width direction, the first portion and the second portion of the first dielectric layer 530 can be disconnected or connected through a third portion of the first dielectric layer 530. The third portion of the first dielectric layer 530 corresponds to the region between the second electrode 520 and the first electrode 510 in the width direction.

[0086] When the first electrode 510 and the first portion of the first dielectric layer 530 approach each other in response to external pressure, the first conductive microstructure 510A contacts the first portion of the first dielectric layer 530 and deforms, thereby changing the capacitance of the second capacitor and generating a sensing signal that changes with the capacitance.

[0087] In some embodiments, the second portion of the first dielectric layer 530 does not have vias. Therefore, the fabrication steps of the first dielectric layer 530 are reduced during the fabrication of the pressure sensor 500, lowering the difficulty of the fabrication process and making the fabrication process of the first dielectric layer 530 more controllable and convenient.

[0088] At this time, the second electrode 520 and the third electrode 560, located on both sides of the first dielectric layer 530 in the thickness direction, can be insulated from each other. The third electrode 560 is not electrically connected to the first electrode 510 or the second electrode 520, and the third electrode 560 serves as a floating electrode. The second electrode 520, the first dielectric layer 530, and the third electrode 560 together form a third capacitor. The second capacitor and the third capacitor are connected in series. Accordingly, the total capacitance value of the pressure sensor 400 can be calculated using the following formula (4): Where C represents the total capacitance of the pressure sensor 400, C1 represents the capacitance of the second capacitor formed by the first electrode 510, the first dielectric layer 530, and the third electrode 560, and C2 represents the capacitance of the third capacitor formed by the second electrode 520, the first dielectric layer 530, and the third electrode 560. Since the contact area between the second electrode 520 and the first dielectric layer 530, and the contact area between the third electrode 560 and the first dielectric layer 530 remain constant, the capacitance C2 of the third capacitor formed by the second electrode 520, the first dielectric layer 530, and the third electrode 560 is a fixed value. The total capacitance C of the pressure sensor 500 changes with the capacitance C1 of the second capacitor formed by the first electrode 510, the first dielectric layer 530, and the third electrode 560.

[0089] In some embodiments, since the third electrode 560 is a floating electrode and not grounded, it is susceptible to electromagnetic interference from the external environment. Therefore, the pressure sensor 500 can be applied in scenarios with low electromagnetic interference, such as when it is installed inside the button housing of an electronic device. The pressure sensor 500 is used to detect the pressure applied to the button. Since the button housing can provide electromagnetic shielding, the pressure sensor 500 is less susceptible to electromagnetic interference.

[0090] To enhance the anti-interference capability of the pressure sensor 500, in some embodiments, an additional grounding shielding layer may be provided on the side of the protective layer 550 facing away from the first substrate 540.

[0091] In other embodiments, the second electrode 520 may also be disposed on the side of the third electrode 560 away from the first electrode 510. A second dielectric layer may be disposed between the second electrode 520 and the third electrode 560. The second electrode 520, the second dielectric layer, and the third electrode 560 may form another third capacitor, which is connected in series with the second capacitor. The total capacitance value of the pressure sensor 500 may be determined with reference to formula (4).

[0092] In some embodiments of this specification, by providing a third electrode 560 and employing a via-less first dielectric layer 530 structure, the fabrication process of the first dielectric layer 530 becomes more controllable and convenient. Simultaneously, the via-less first dielectric layer 530 also insulates the second electrodes 520 and the third electrode 560 on both sides from each other, thereby forming a third capacitor between the second electrodes 520 and the third electrode 560, further enhancing the sensitivity of the pressure sensor 500.

[0093] Figure 6 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0094] As shown in Figure 6, the pressure sensor 500 includes a first electrode 610, a second electrode 620, a first dielectric layer 630, and a first substrate 640. The first electrode 610 has a first conductive microstructure 610A configured to contact the first dielectric layer 630. The first electrode 610 includes a first elastic conductor 611 and a first conductor 612, and the first conductive microstructure 610A is disposed on the surface of the first elastic conductor 611 facing the first dielectric layer 630. The first electrode 610, the first conductive microstructure 610A, and the first substrate 640 are the same as or similar to the first electrode 410, the first conductive microstructure 410A, and the first substrate 440 in Figure 4.

[0095] The second electrode 620 includes a first portion 621 and a second portion 622. The first portion 621 includes a second conductor 6211, which is fixedly connected to the second portion 622 of the second electrode 620 via a conductive adhesive layer 623. The second portion 622 of the second electrode 620 includes a third conductor 6221. The first portion 621 of the second electrode 620 is the same as or similar to the first portion 421 of the second electrode 420 in FIG. 4.

[0096] In some embodiments, the first portion 621 and the first electrode 610 are disposed on the same side of the third conductor 6221, and the first electrode 610 and the first dielectric layer 630 are both located within the annular first portion 621 or the annular conductive adhesive layer 623. The third conductor 6221 and the second conductor 6211 are directly connected through the conductive adhesive layer 623. In this case, through the electrical connection between the third conductor 6221, the conductive adhesive layer 623, and the second conductor 6211, the third conductor 6221 can be connected to the first electrode 610 on the same circuit board.

[0097] In some embodiments, the pressure sensor 600 further includes a third electrode 660 disposed on the side of the first dielectric layer 630 opposite to the first electrode 610.

[0098] The third electrode 660 has a first surface opposite to the first electrode 610 and a second surface opposite to the second electrode 620. Specifically, the third electrode 660 includes a second surface opposite to the second portion 622 of the second electrode 620. As shown in FIG6, in some embodiments, the first surface and the second surface of the third electrode 660 are two surfaces of the third electrode 660 that are opposite to each other.

[0099] The pressure sensor 600 includes a first dielectric layer 630 located on a first surface of a third electrode 660 and a second dielectric layer 670 located on a second surface of the third electrode 660. In other embodiments, the first dielectric layer 630 and the second dielectric layer 670 may also be considered as two portions of the same dielectric layer located on different surfaces of the third electrode 660.

[0100] A second capacitor is formed between the first electrode 610, the first dielectric layer 630, and the third electrode 660, and a third capacitor is formed between the third electrode 660, the second dielectric layer 670, and the second portion 622 of the second electrode 620. The second capacitor and the third capacitor are connected in series.

[0101] When the first electrode 610 and the first dielectric layer 630 approach each other in response to external pressure, the first conductive microstructure 610A contacts the first portion of the first dielectric layer 630 and deforms, thereby changing the capacitance of the second capacitor and generating a sensing signal that changes with the capacitance.

[0102] In some embodiments, a second conductive microstructure 620A configured to contact the second dielectric layer 670 is disposed on the second electrode 620. Specifically, the second conductive microstructure 620A is disposed on the second portion 622 of the second electrode 620. When the second portion 622 of the second electrode 620 and the second dielectric layer 670 approach each other in response to external pressure, the second conductive microstructure 620A contacts the second dielectric layer 670 and deforms, thereby changing the capacitance of the third capacitor and generating a sensing signal that changes with the capacitance.

[0103] In some embodiments, the second conductive microstructure 620A may have the same or similar material, size, structure, etc. as the first conductive microstructure 610A (or the first conductive microstructure 210A).

[0104] In some embodiments, the second portion 622 of the second electrode 620 further includes a second elastic conductor 6222. A second conductive microstructure 620A is formed on the surface of the second elastic conductor 6222 facing the second dielectric layer 670. The second elastic conductor 6222 is located on the side of the third conductor 6221 facing the first electrode 610. The second elastic conductor 6222 may have the same or similar material and structure as the first elastic conductor 611 (or the first elastic conductor 211).

[0105] In some embodiments, the pressure sensor 600 may not have a protective layer. Accordingly, the pressure sensor 600 may include a second substrate 680. The second substrate 680 and the first substrate 640 may be located on two surfaces in the thickness direction of the pressure sensor 600, so that both surfaces in the thickness direction of the pressure sensor 600 can be used as sensitive areas to be subjected to external pressure.

[0106] In some embodiments, the total capacitance of the pressure sensor 600 can be calculated using the following formula (5): Where C represents the total capacitance of the pressure sensor 600, C1 represents the capacitance of the second capacitor formed by the first electrode 610, the first dielectric layer 630, and the third electrode 660, and C3 represents the capacitance of the third capacitor formed by the second part 622 of the second electrode 620, the second dielectric layer 670, and the third electrode 660. C1 and C2 are variables controlled by external pressure; therefore, the total capacitance C of the pressure sensor 600 has higher sensitivity.

[0107] In some embodiments of this specification, by designing the second electrode 620 and setting the third electrode 660 and the second dielectric layer 670, the capacitance C1 of the second capacitor formed by the first electrode 610, the first dielectric layer 630, and the third electrode 660, and the capacitance C2 of the third capacitor formed by the second part 622 of the second electrode 620, the second dielectric layer 670, and the third electrode 660, are all variables controlled by external pressure, thereby improving the sensitivity of the total capacitance C of the pressure sensor 600.

[0108] Figure 7 is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0109] As shown in Figure 7, the pressure sensor 700 includes a first electrode 710, a second electrode 720, a first dielectric layer 730, a first substrate 740, and a protective layer 750. The first electrode 710 has a first conductive microstructure 710A configured to contact the first dielectric layer 730. The first electrode 710 includes a first elastic conductor 711 and a first conductor 712, and the first conductive microstructure 710A is disposed on the surface of the first elastic conductor 711 facing the first dielectric layer 730. The second electrode 720 includes a first portion 721 and a second portion 722. The first portion 721 includes a second conductor 7211, which is fixedly connected to the first dielectric layer 730 via a conductive adhesive layer 723. The second portion 722 includes a third conductor 7221 (or, a third electrode 760). The first electrode 710, the first conductive microstructure 710A, the second electrode 720, the first dielectric layer 730, the first substrate 740, and the protective layer 750 are the same as or similar to the first electrode 410, the first conductive microstructure 410A, the second electrode 420, the first dielectric layer 430, the first substrate 440, and the protective layer 450 in FIG4.

[0110] During use, when other conductors (such as human skin or liquids like sweat or water) come into contact with or approach the pressure sensor 700, parasitic capacitance is introduced between these other conductors and the electrodes (such as the first electrode 710), thereby changing the capacitance measurement value of the pressure sensor. To solve this problem, the pressure sensor 700 may further include a conductive shielding layer 790, which is disposed on a second side of the first substrate 740 opposite to the first side. The second side of the first substrate 740 is the side of the first substrate 740 facing away from the first electrode 710. In some embodiments, the conductive shielding layer 790 and the second electrode 720 are configured to be grounded. The conductive shielding layer 790, the second conductor 7211, the conductive adhesive layer 723, and the third conductor 7221 surround the first conductor 712 and are grounded, thereby effectively shielding the parasitic capacitance generated when other conductors come into contact with or approach the pressure sensor 700, thereby improving the measurement accuracy of the pressure sensor 700.

[0111] In some embodiments, the material of the conductive shielding layer 790 may include a conductor, and the material of the conductive shielding layer 790 may be the same as or similar to that of the first conductor 712, the second conductor 7211, and the third conductor 7221.

[0112] In some embodiments, the pressure sensor 700 may further include another protective layer 780, which may be disposed on the side of the conductive shielding layer 790 facing away from the first substrate 740. The other protective layer 780 can protect the conductive shielding layer 790 and improve the reliability of the pressure sensor 700. The material and structure of the other protective layer 780 may be the same as or similar to that of the protective layer 750.

[0113] In some embodiments of this specification, by providing a conductive shielding layer on the outside of the pressure sensor 700, the parasitic capacitance generated when other conductors contact or approach the pressure sensor 700 is effectively shielded, thereby improving the measurement accuracy of the pressure sensor 700 and enhancing its reliability and anti-interference capability.

[0114] The pressure sensors provided in the various embodiments of this specification can be applied to headphones, glasses, wristbands, watches, rings, heart rate monitors, etc. In practical applications, the unshielded side of the pressure sensor (the side where the first substrate 410 is located in Figure 4) can be placed inside electronic devices such as headphones, while the shielded side (the side where the protective layer 450 is located in Figure 4) can be placed on the outside, thereby improving the reliability and anti-interference capability of the pressure sensor in practical applications.

[0115] Figures 8A-8E are schematic flowcharts illustrating the fabrication method of a pressure sensor according to some embodiments of this specification.

[0116] Please refer to Figures 8A-8E. Some embodiments of this specification also provide a method for preparing a pressure sensor.

[0117] Referring to Figure 8A, the fabrication method includes: fabricating a first conductor layer on a first side of a first substrate 840, the first conductor layer including a first conductor 812 and a second conductor 8211 separated from each other. In some embodiments, the first conductor 812 may correspond to the first conductor 412 of Figure 4, the second conductor 8211 may correspond to the second conductor 4211 of Figure 4, and the first substrate 840 may correspond to the first substrate 440 of Figure 4.

[0118] In some embodiments, the second conductor 8211 can be a ring, and the first conductor 812 is located within the ring. The second conductor 8211 can serve as a support and fixation element, protecting the capacitor subsequently formed by the first conductor 812, thereby shielding electromagnetic interference to a certain extent, improving the measurement accuracy of the pressure sensor, and enhancing the reliability and anti-interference capability of the pressure sensor.

[0119] Referring to Figure 8B, the fabrication method further includes: fabricating an elastic conductive microstructure 810A on the side of the first conductor 812 away from the first substrate 840. In some embodiments, the elastic conductive microstructure 810A may correspond to the first conductive microstructure 410A in Figure 4.

[0120] In some embodiments, fabricating an elastic conductive microstructure 810A on the side of the first conductor 812 away from the first substrate 840 may include: printing conductive silicone ink containing foamed particles on the side of the first conductor 812 away from the first substrate 840; or, printing conductive silicone ink on the side of the first conductor 812 away from the first substrate 840 and pressing it onto the conductive silicone ink using a mold to obtain the elastic conductive microstructure 810A.

[0121] In some embodiments, the material of the foamed particles may include polystyrene (EPS / EPP), polyethylene (EVA / PE), thermoplastic elastomers (TPE / TPU), polyvinyl chloride (PVC), etc. Conductive silicone ink incorporating foamed particles can form an elastic conductive microstructure 810A under the foaming process.

[0122] In some embodiments, the conductive silicone ink can be replaced by other elastic conductive inks (e.g., conductive PDMS ink, etc.). In some embodiments, when the conductive silicone ink or other elastic conductive ink is not fully cured, it can be imprinted using a mold. After it is fully cured, the mold is removed to obtain an elastic conductor 811 having an elastic conductive microstructure 810A. The elastic conductor 811 can correspond to the first elastic conductor 411 in FIG4.

[0123] Referring to Figure 8C, the fabrication method further includes: fabricating a second conductor layer 8221. In some embodiments, the second conductor layer 8221 may correspond to the third conductor 8221 in Figure 4.

[0124] In some embodiments, a second conductor layer 8221 may be formed on a first side of the second substrate 850, specifically in a manner similar to the fabrication of the first conductor layer. In some embodiments, a metal plate of a predetermined size may also be directly obtained and used as the second conductor layer 8221.

[0125] Referring to Figure 8D, the fabrication method further includes forming a dielectric layer 830 on the second conductor layer 8221. In some embodiments, the dielectric layer 830 may correspond to the first dielectric layer 430 of Figure 4.

[0126] In some embodiments, forming a dielectric layer 830 on the second conductor layer 8221 may include: forming the dielectric layer 830 on the second conductor layer 8221 by anodizing; or forming the dielectric layer 830 on the second conductor layer 8221 by physical vapor deposition.

[0127] In some embodiments, the main flow of the anodizing process includes pretreatment and oxidation, and the metal substrate for the anodizing process may include aluminum. The pretreatment step is mainly used to remove impurities, oil, and oxide layers from the aluminum surface to ensure uniformity during subsequent anodizing and the quality of the formed film (e.g., dielectric layer 830). The oxidation step mainly generates an aluminum oxide film on the aluminum alloy surface through an electrochemical method.

[0128] In some embodiments, the pretreatment steps may include chemical degreasing (alkaline solution) or ultrasonic cleaning, alkaline etching (removing the natural oxide film on the surface and slightly etching the surface to expose a uniform metal substrate), pickling (neutralizing residual alkaline solution and removing aluminum hydroxide from the surface to make the surface smooth), and water washing (thoroughly rinsing with deionized water after each of the above steps to prevent cross-contamination of solutions).

[0129] In some embodiments, during the oxidation step, the anode material may include metallic aluminum or an aluminum alloy, and the cathode material may include lead plate or graphite; the electrolyte used may be a sulfuric acid solution, for example, a sulfuric acid solution with a mass fraction of 15-20%; the ambient temperature may be 18-22°C; the voltage may be a DC voltage of 12-20V; and the current density may be 1A / dm³. 2 -2A / dm 2 The duration can be 30s-120s. The duration of the oxidation step can be adjusted according to the required thickness of the dielectric layer 830 to ensure that the thickness of the dielectric layer is less than 5μm, thereby enabling the fabricated pressure sensor to have high sensitivity.

[0130] In some embodiments, when a metal plate of a preset size is used directly as the second conductor layer 8221, a dielectric layer 830 can be formed on the surface of the metal plate by anodizing, wherein one dielectric layer 830 serves as a protective layer (corresponding to the protective layer 450 in FIG4).

[0131] In some embodiments, where a second conductor layer 8221 is formed on a first side of the second substrate 850, a dielectric layer 830 can be formed on the surface of the second conductor layer 8221 away from the first side of the second substrate 850 by anodizing.

[0132] Referring to Figure 8E, the fabrication method further includes: placing one side of a first substrate 840 with an elastic conductor microstructure 810A opposite to one side of a second substrate 850 with a dielectric layer 830, and fixing the second conductor 8211 to a portion of the dielectric layer 830. The second substrate 850 may correspond to the protective layer 450 in Figure 4 or the second substrate 680 in Figure 6.

[0133] In some embodiments, the second conductor 8211 may be fixedly connected to a portion of the dielectric layer 830 by covering one side of the second conductor 8211 with a conductive adhesive layer 823 (e.g., by pasting the conductive adhesive layer 823 or by screen printing the conductive adhesive layer 823). The conductive adhesive layer 823 may correspond to the conductive adhesive layer 423 in FIG4.

[0134] In some embodiments, the method of fixing the second conductor 8211 to a portion of the dielectric layer 830 may also include: placing the first side of the first substrate 840 with the conductive adhesive layer 823 opposite to the first side of the second substrate 850 with the dielectric layer 830 and applying pressure, so that the conductive adhesive layer 823 is bonded to a portion of the dielectric layer 830.

[0135] Figures 9A-9G are schematic flowcharts illustrating methods for fabricating pressure sensors according to other embodiments of this specification.

[0136] Please refer to Figures 9A-9G. Some embodiments of this specification also provide another method for preparing a pressure sensor.

[0137] Referring to FIG9A, the fabrication method includes: fabricating a first conductor layer on a first side of a first substrate 940, the first conductor layer including a first conductor 912 and a second conductor 9211 separated from each other. In some embodiments, the first conductor 912 may correspond to the first conductor 612 of FIG6, the second conductor 9211 may correspond to the second conductor 6211 of FIG6, and the first substrate 940 may correspond to the first substrate 640 of FIG6.

[0138] Referring to FIG9B, the fabrication method further includes: fabricating an elastic conductive microstructure 910A on the side of the first conductor 912 away from the first substrate 940. In some embodiments, the elastic conductive microstructure 910A may correspond to the first conductive microstructure 610A of FIG6.

[0139] Referring to Figure 9C, the fabrication method further includes: fabricating a second conductor layer 960. In some embodiments, the second conductor layer 960 may correspond to the third electrode 660 of Figure 6.

[0140] In some embodiments, the steps shown in Figures 9A-9C are the same as or similar to the steps shown in Figures 8A-8C.

[0141] Referring to Figure 9D, in some embodiments, the fabrication method further includes forming dielectric layers on two opposing surfaces of the second conductor layer 960. That is, a first dielectric layer 930 and a second dielectric layer 970 are formed on the two surfaces of the second conductor layer 960, respectively. In some embodiments, the first dielectric layer 930 may correspond to the first dielectric layer 630 of FIG. 6, and the second dielectric layer 970 may correspond to the second dielectric layer 670 of FIG. 6.

[0142] Based on the steps shown in Figure 9D, the two surfaces of the second conductor 9211 are processed respectively to complete the steps shown in Figure 9D.

[0143] Referring to Figure 9E, the fabrication method further includes: fabricating a third conductor layer 9221 on a first side of the second substrate 980. The second substrate 980 can correspond to the second substrate 680 shown in Figure 6, and the third conductor layer 9221 can correspond to the third conductor 6221 in Figure 6. The fabrication method of the third conductor layer 9221 is the same as or similar to that of the first conductor layer.

[0144] Referring to Figure 9F, the fabrication method further includes: fabricating an elastic conductive microstructure 920A on the side of the third conductor layer 9221 away from the second substrate 980. The elastic conductive microstructure 920A can correspond to the second conductive microstructure 620A in Figure 6. The fabrication method of the elastic conductive microstructure 920A is the same as or similar to that of the elastic conductive microstructure 910A.

[0145] Referring to Figure 9G, the fabrication method further includes: placing the first side of the first substrate 940 opposite to the dielectric layer 930 on one surface of the second conductor layer 960, placing the first side of the second substrate 980 opposite to the dielectric layer 970 on another surface of the second conductor layer 960, and fixing a portion of the second conductor 9211 to the third conductor layer 9221.

[0146] In some embodiments, the way in which the second conductor 9211 is fixedly connected to a portion of the third conductor layer 9221 is the same as or similar to the way in which the second conductor 8211 is fixedly connected to a portion of the dielectric layer 830, and will not be described again here.

[0147] The aforementioned pressure sensor can be efficiently manufactured using the preparation methods described in one or more embodiments, which is beneficial for large-scale production.

[0148] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0149] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0150] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0151] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the specific characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ general methods of digit reservation. Although the numerical ranges and parameters used to confirm their breadth in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0152] For each patent, patent application, patent application publication, etc., referenced in this application, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this application, as well as documents that limit the broadest scope of the claims of this application (currently or subsequently appended to this application). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or terminology used in the supplementary materials of this application and the content of this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0153] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A pressure sensor, comprising a first electrode, a second electrode, and a capacitor formed by a dielectric layer disposed opposite to the second electrode; The first electrode has a first conductive microstructure configured to contact the dielectric layer; when the first electrode and the dielectric layer approach each other in response to external pressure, the first conductive microstructure contacts the dielectric layer and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance. The thickness of the dielectric layer is less than 5 μm.

2. The pressure sensor according to claim 1, wherein, The thickness of the dielectric layer is less than 500 nm.

3. The pressure sensor according to claim 1, wherein, The relative permittivity of the dielectric layer is greater than 2.

4. The pressure sensor according to claim 1, wherein, The dielectric layer is formed by anodizing or physical vapor deposition.

5. The pressure sensor according to claim 1, wherein, The dielectric layer is made of materials including, but not limited to, one or more combinations of the following: aluminum oxide, titanium dioxide, magnesium oxide, barium titanate, insulating resin, and parylene.

6. The pressure sensor according to claim 1, wherein, The first electrode includes a first elastic conductor, and the first conductive microstructure is disposed on the surface of the first elastic conductor.

7. The pressure sensor according to claim 1, wherein, It also includes a third electrode; The third electrode has a first surface opposite to the first electrode and a second surface opposite to the second electrode; The dielectric layer includes a first portion located on the first surface and a second portion located on the second surface; When the first electrode and the first portion of the dielectric layer approach each other in response to external pressure, the first conductive microstructure contacts the first portion of the dielectric layer and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance.

8. The pressure sensor according to claim 7, wherein, The first surface and the second surface are different regions on the same surface of the third electrode; the second electrode is in contact with a second portion of the dielectric layer.

9. The pressure sensor according to claim 7, wherein, A second conductive microstructure configured to contact the dielectric layer is disposed on the second electrode; When the second electrode and the second portion of the dielectric layer approach each other in response to external pressure, the second conductive microstructure contacts the second portion of the dielectric layer and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance.

10. The pressure sensor according to claim 9, wherein, The first surface and the second surface are two surfaces on the third electrode that are opposite to each other.

11. The pressure sensor according to claim 9, wherein, The second electrode includes a second elastic conductor, and the second conductive microstructure is formed on the surface of the second elastic conductor.

12. The pressure sensor according to claim 1 or 9, wherein, The longitudinal distance between the protrusions and concave points of the first conductive microstructure is less than 300 μm, and the lateral distance between adjacent protrusions and concave points of the first conductive microstructure is less than 1 mm. Alternatively, the longitudinal distance between the protrusions and concave points of the second conductive microstructure is less than 300 μm, and the lateral distance between adjacent protrusions and concave points of the second conductive microstructure is less than 1 mm.

13. The pressure sensor according to claim 1, wherein, It also includes a first substrate; the second electrode includes a first portion and a second portion; The first electrode and the first portion of the second electrode are disposed on the first side surface of the first substrate; the first portion of the second electrode is annular, and the first electrode is located inside the annular shape. The second portion of the second electrode is disposed opposite to the first electrode and the first portion of the second electrode; The dielectric layer is disposed on the second portion of the second electrode on the side close to the first electrode; The first part of the second electrode is electrically and fixedly connected to the second part of the second electrode.

14. The pressure sensor according to claim 13, wherein, It also includes a conductive shielding layer; The conductive shielding layer is disposed on the second side of the first substrate, and the second side of the first substrate is disposed opposite to the first side of the first substrate.

15. The pressure sensor according to claim 14, wherein, The conductive shielding layer and the second electrode are configured to be grounded.

16. The pressure sensor according to claim 13, wherein, The second portion of the second electrode has a first surface opposite to the first electrode and a second surface opposite to the first portion of the second electrode; The dielectric layer includes a first portion located on the first surface and a second portion located on the second surface; The second part of the dielectric layer has a through hole, and the first part of the second electrode and the second part of the second electrode are fixedly connected by conductive adhesive that passes through the through hole; When the first electrode and the first portion of the dielectric layer approach each other in response to external pressure, the first conductive microstructure contacts the first portion of the dielectric layer and deforms, thereby changing the capacitance and generating a sensing signal that changes with the capacitance.

17. The pressure sensor according to claim 13 or 16, wherein, The first part of the second electrode and the second part of the second electrode are fixedly connected by conductive adhesive; the melting point of the conductive adhesive is lower than the melting point of the first conductive microstructure.

18. A method for manufacturing a pressure sensor, comprising: A first conductor layer is formed on a first side of a first substrate, the first conductor layer comprising a first conductor and a second conductor that are separated from each other; An elastic conductive microstructure is fabricated on the side of the first conductor away from the first substrate; Fabricate a second conductor layer; A dielectric layer is formed on the second conductor layer; One side of the first substrate with the elastic conductor microstructure is placed opposite the side of the second substrate with the dielectric layer, such that the second conductor is fixedly connected to a portion of the dielectric layer.

19. The preparation method according to claim 18, wherein, The second conductor is ring-shaped, and the first conductor is located inside the ring.

20. The preparation method according to claim 18, wherein, The step of fabricating an elastic conductive microstructure on the side of the first conductor away from the first substrate includes: The first conductor is printed with conductive silicone ink containing foamed particles on the side away from the first substrate; or, conductive silicone ink is printed on the first conductor on the side away from the first substrate, and then the conductive silicone ink is pressed onto the conductive silicone ink using a mold to obtain the elastic conductive microstructure.

21. The preparation method according to claim 18, wherein, The formation of a dielectric layer on the second conductor layer includes: forming the dielectric layer on the second conductor layer by anodizing; or forming the dielectric layer on the second conductor layer by physical vapor deposition.

22. A method for manufacturing a pressure sensor, comprising: A first conductor layer is formed on a first side of a first substrate, the first conductor layer comprising a first conductor and a second conductor that are separated from each other; An elastic conductive microstructure is fabricated on the side of the first conductor away from the first substrate; Fabricate a second conductor layer; A dielectric layer is formed on two opposing surfaces of the second conductor layer; A third conductor layer is fabricated on the first side of the second substrate; An elastic conductive microstructure is fabricated on the side of the third conductor layer away from the second substrate; The first side of the first substrate is aligned with the dielectric layer on one surface of the second conductor layer, and the first side of the second substrate is aligned with the dielectric layer on the other surface of the second conductor layer, such that the second conductor is fixedly connected to a portion of the third conductor layer.

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