Pressure sensor

Abstract

A pressure sensor (200). The pressure sensor (200) comprises: a first capacitor formed by a first electrode (230), a second electrode (250), and a first dielectric layer (240) located therebetween, wherein a first conductive microstructure (234) in contact with the first dielectric layer (240) is arranged on the first electrode (230), and when the first electrode (230) approaches the second electrode (250) in response to an external pressure, the first conductive microstructure (234) undergoes deformation, and the deformation alters first capacitance of the first capacitor and generates a sensing signal that varies with the first capacitance.

Description

A pressure sensor Technical Field

[0001] This application relates to the field of sensing, and in particular to a pressure sensor. Background Technology

[0002] 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.

[0003] Based on this, we aim to propose a pressure sensor with a simple structure that can save on the design and manufacturing costs of pressure sensors while ensuring high accuracy and sensitivity.

[0004] Summary of the Invention

[0005] This specification provides a pressure sensor comprising: a first electrode, a second electrode, and a first capacitor formed by a first dielectric layer located between the two. The first electrode has a first conductive microstructure disposed therein, in contact with the first dielectric layer. When the first electrode moves closer to the second electrode in response to external pressure, the first conductive microstructure deforms, changing the first capacitance of the first capacitor and generating a sensing signal that changes with the first capacitance. With this configuration, when the sensitive area of ​​the pressure sensor is subjected to pressure, although the gap between the bottom of the first electrode and the second electrode (i.e., the thickness of the first dielectric layer) remains unchanged, the presence of the first conductive microstructure causes deformation within the microstructure, resulting in changes in its contact area with the first dielectric layer and its equivalent dielectric constant. This leads to a higher sensitivity of the pressure sensor compared to traditional variable-gap pressure sensors.

[0006] In some embodiments, the first conductive microstructure includes a plurality of spaced flexible conductive protrusions, with pores formed between the flexible conductive protrusions. This configuration allows the flexible conductive protrusions to easily deform when pressure is applied to the sensitive area of ​​the pressure sensor, resulting in significant changes in their contact area with the first dielectric layer and their equivalent dielectric constant, thereby giving the pressure sensor higher sensitivity.

[0007] In some embodiments, the first conductive microstructure is formed from a conductive sponge with a metal coating or a conductive foam material with a metal coating.

[0008] In some embodiments, the flexible conductive protrusion is formed of conductive silicone or conductive polydimethylsiloxane (PDMS).

[0009] In some embodiments, the thickness of the flexible conductive protrusion ranges from 1 μm to 500 μm, and the size of the pores in the flexible conductive protrusion ranges from 1 μm to 500 μm. This configuration allows the pressure sensor to have high sensitivity while maintaining a small size, thus achieving device miniaturization.

[0010] In some embodiments, when not subjected to external pressure, the ratio of the contact area between the first conductive microstructure and the first dielectric layer to the area of ​​the first dielectric layer is between one ten-thousandth and one tenth.

[0011] In some embodiments, the flexible conductive protrusions in the first conductive microstructure are non-uniformly distributed.

[0012] In some embodiments, the first electrode includes: a conductive layer, a conductive connection layer, and a conductive microstructure layer stacked sequentially, wherein the first conductive microstructure is located on the side of the conductive microstructure layer away from the conductive layer. This configuration makes the structure of the first electrode more stable.

[0013] In some embodiments, the conductive layer is formed of flexible conductive silicone or indium tin oxide (ITO) conductive film or metal; the conductive connection layer is formed of conductive silicone, conductive cloth, conductive tape or conductive epoxy; and the conductive microstructure layer is formed of conductive sponge with metal material plated on the surface, conductive foam material with metal material plated on the surface, conductive silicone or conductive polydimethylsiloxane (PDMS) doped with conductive particles.

[0014] In some embodiments, the thickness of the first dielectric layer is less than 20 μm, and the relative permittivity of the first dielectric layer is greater than 2. This configuration allows the pressure sensor to maintain a high level of sensitivity and to be small in size for ease of use.

[0015] In some embodiments, the thickness of the first dielectric layer is less than 2 μm, and the relative permittivity of the first dielectric layer is greater than 3. This configuration allows the pressure sensor to maintain a higher level of sensitivity and to be smaller in size for easier use.

[0016] In some embodiments, a dielectric microstructure in contact with the first electrode or the second electrode is disposed on the first dielectric layer, the dielectric microstructure comprising a plurality of spaced flexible dielectric protrusions. By providing a dielectric microstructure capable of elastic deformation, similar to the first conductive microstructure, on the first dielectric layer, the variation in the contact area between the first dielectric layer and the electrode (first electrode or second electrode) can be further increased, thereby improving the sensitivity of the pressure sensor.

[0017] In some embodiments, a second conductive microstructure is disposed on the second electrode in contact with the first dielectric layer. This arrangement allows the contact area between the second electrode and the first dielectric layer to change under external pressure, thereby improving the sensitivity of the pressure sensor.

[0018] In some embodiments, the first conductive microstructure and the second conductive microstructure are formed of different materials. This arrangement can prevent mutual misalignment between the first dielectric layer and the upper and lower electrodes (the first electrode or the second electrode).

[0019] In some embodiments, the pressure sensor further includes a third electrode, wherein the first electrode, the second electrode, and the third electrode are arranged at intervals, and the two outermost electrodes are grounded. This configuration can shield the pressure sensor from interference from external electrical or magnetic signals, thereby improving the accuracy of the internal sensing signal of the pressure sensor.

[0020] In some embodiments, the pressure sensor further includes a second capacitor formed by a third electrode, a fourth electrode, and a second dielectric layer located between the third and fourth electrodes, wherein the first and second capacitors are arranged along the pressure-sensitive direction of the pressure sensor. By forming two capacitors in the pressure sensor, both capacitors can be affected by external pressure and output sensing signals.

[0021] In some embodiments, the two outermost electrodes in the pressure-sensitive direction are grounded, and the two middle electrodes are electrically connected. Grounding the outer electrodes can shield the pressure sensor from interference from external electrical or magnetic signals, thereby improving the accuracy of the internal sensing signal. Furthermore, by electrically connecting the two middle electrodes, the two capacitors can also be considered as a parallel structure (the total capacitance of the two capacitors is greater than that of a single capacitor), improving the sensitivity of the pressure sensor; or the sensing signals of the two capacitors can be output separately, avoiding mutual interference between the two capacitors and further improving the sensitivity of the pressure sensor.

[0022] In some embodiments, the pressure sensor further includes a second capacitor formed by a third electrode, a fourth electrode, and a second dielectric layer located between the third electrode and the fourth electrode, wherein the second capacitor and the first capacitor are spaced apart along a direction perpendicular to the pressure-sensitive direction of the pressure sensor. By arranging the second capacitor and the first capacitor spaced apart along a direction perpendicular to the pressure-sensitive direction of the pressure sensor, simultaneous measurement of the location and magnitude of the external pressure source can be achieved.

[0023] In some embodiments, the first electrode and the third electrode are electrically connected, and a fifth electrode is provided on the side of the second electrode and the fourth electrode opposite to the first electrode and the third electrode. The first electrode, the third electrode, and the fifth electrode are grounded. This configuration can shield the internal sensing signal of the pressure sensor from interference from external electrical or magnetic signals, thereby improving the accuracy of the internal sensing signal of the pressure sensor.

[0024] In some embodiments, the first electrode and the third electrode are two different regions on a single electrode. This configuration further simplifies the structure and fabrication process of the pressure sensor.

[0025] In some embodiments, the pressure sensor further includes a third electrode located on the same side as the second electrode as the first electrode, the second electrode and the third electrode respectively facing different regions on the first electrode, and a second dielectric layer existing between the third electrode and the first electrode to form a second capacitor. By placing the third electrode and the second electrode on the same side of the first electrode, when connecting the pressure sensor to an external circuit, only the second and third electrodes need to be wired out, without requiring lead design for the first electrode. Since the second and third electrodes are both located on the same side of the capacitor, they can be easily connected to the same circuit board, thereby reducing the difficulty of wire design for the pressure sensor and significantly simplifying the structure and manufacturing process. Attached Figure Description

[0026] This application 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:

[0027] Figure 1 is a schematic diagram of the structure of an ionized pressure sensor according to some embodiments of this specification;

[0028] Figure 2A is a schematic diagram of the structure of a pressure sensor according to some embodiments of this specification;

[0029] Figure 2B is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0030] Figure 2C is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0031] Figure 2D is a schematic diagram of the structure of the conductive microstructure shown in some embodiments according to this specification;

[0032] Figure 2E is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0033] Figure 2F is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0034] Figure 3A is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0035] Figure 3B is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0036] Figure 4A is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0037] Figure 4B is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0038] Figure 5A is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0039] Figure 5B is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0040] Figure 5C is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0041] Figure 5D is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification;

[0042] Figure 5E is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0043] Figure 5F is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification;

[0044] Figure 6A is a sensitivity test diagram of a pressure sensor according to some embodiments of this specification; and

[0045] Figure 6B is a reliability test diagram of a pressure sensor according to some embodiments of this specification. Detailed Implementation

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. 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.

[0047] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0048] As indicated in this application 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 explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0049] In the description of this specification, it should be understood that the terms "first," "second," "third," "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include at least one of that feature. In the description of this specification, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this specification, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, the term "connection" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0051] Pressure sensors are used to convert pressure signals into electrical signals in order to detect pressure.

[0052] Traditional capacitive pressure sensors (also known as flat-plate pressure sensors) are a typical pressure sensor solution. They include 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 the capacitance of the parallel-plate capacitor to change. The resulting electrical signal can reflect the presence of external pressure, and even further, the magnitude of the external pressure.

[0053] 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.

[0054] Figure 1 is a schematic diagram of the structure of an ionized pressure sensor according to some embodiments of this specification.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Figure 2A is a schematic diagram of the structure of a pressure sensor according to some embodiments of this specification; Figure 2B is a schematic diagram of the structure of a pressure sensor according to other embodiments of this specification; Figure 2C is a schematic diagram of the structure of a pressure sensor according to other embodiments of this specification; Figure 2D is a schematic diagram of the structure of a conductive microstructure according to some embodiments of this specification.

[0060] As shown in Figure 2A, the pressure sensor 200 includes a first capacitor formed by a first electrode 230, a second electrode 250, and a first dielectric layer 240 located between them. A first conductive microstructure 234 is disposed on the first electrode 230, in contact with the first dielectric layer 240. In this specification, the first conductive microstructure refers to a structure capable of conducting electricity and containing pores (or voids). When the first electrode 230 moves closer to the second electrode 250 in response to external pressure, the first conductive microstructure 234 deforms. This deformation changes the first capacitance of the first capacitor and generates a sensing signal that changes with the first capacitance.

[0061] As shown in Figure 2A, the pressure sensor 200 also includes a substrate 211, a substrate 212 and a support 220 located around the first capacitor. The substrate 211 and the substrate 212 are located outside the first electrode 230 and the second electrode 250, respectively, and the support 220 is located between the substrate 211 and the substrate 212 and surrounds the first capacitor.

[0062] 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 Figures 2A to 2C. The pressure sensor 200 has a sensitive area P. When external pressure is applied to this sensitive area P (for example, on the surface of the substrate 211 or 212 directly opposite the sensitive area P), the pressure sensor 200 can accurately identify the external pressure.

[0063] Specifically, there are gaps in the first conductive microstructure 234. When the sensitive area of ​​the pressure sensor 200 is subjected to pressure, although the gap between the bottom of the first electrode 230 and the second electrode 250 (i.e. the thickness of the first dielectric layer 240) remains unchanged, the presence of the first conductive microstructure 234 causes deformation inside the first conductive microstructure 234, resulting in changes in the contact area between it and the first dielectric layer 240 and the equivalent dielectric constant. This makes the pressure sensor 200 have higher sensitivity than traditional variable-gap pressure sensors.

[0064] 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)

[0065] 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 234 in contact with the first dielectric layer 240; C2 is the capacitance generated by the portion of the first conductive microstructure 234 not in contact with the first dielectric layer 240; t is the thickness of the first dielectric layer 240; ε0 is the absolute dielectric constant; εr1 ε is the relative permittivity of the first dielectric layer 240; S1 is the contact area between the first conductive microstructure 234 and the first dielectric layer 240; S2 is the area of ​​the portion of the first conductive microstructure 234 that is not in contact with the first dielectric layer 240 (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 240; d is the average distance between the non-contact portion of the first electrode 230 (or the first conductive microstructure 234) and the second electrode 250.

[0066] As can be seen from the above formulas (1) to (3), C1 is proportional to S1, while C2 is proportional to S2. When the pressure sensor 200 is subjected to external pressure, the interior of the first conductive microstructure (e.g., the flexible conductive protrusion described below) 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 234 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 240 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.

[0067] Substrates 211 and 212 provide housing protection for the pressure sensor 200. Substrates 211 and 212 are themselves non-conductive. In some embodiments, substrates 211 and 212 can be quasi-rigid printed circuit boards or flexible printed circuit boards, or they can be made of flexible insulating materials such as polyethylene terephthalate (PET), polyimide (PI), polydimethylsiloxane (PDMS), or silicone. The thickness of substrates 211 and 212 can range from 5 μm to 500 μm.

[0068] The support 220 serves to support and fix the pressure sensor 200. The support 220 can be made of insulating adhesives, such as hot melt adhesive, silicone, epoxy, double-sided tape, etc., and is used to bond the substrate 211 and substrate 212 and provide support. As shown in Figure 2A, the support 220, substrate 211, and substrate 212 can form a cavity 260, which can accommodate the first electrode 230, the first dielectric layer 240, and the second electrode 250, thereby protecting the first capacitor formed by the first electrode 230, the first dielectric layer 240, and the second electrode 250.

[0069] In some embodiments, the first electrode 230 is a single-layer conductor structure. In this specification, a single-layer structure refers to a structure made of the same material. For example, the first electrode 230 is a single-layer structure made of conductive silicone, conductive PDMS, or other flexible conductive materials. Based on this, a first conductive microstructure is present on the surface of the first electrode 230, which contacts the first dielectric layer 240. The first conductive microstructure is made of conductive silicone, conductive PDMS, or other flexible conductive materials doped with conductive particles (the same material as the first electrode 230). For example, if the first electrode 230 is made of conductive silicone, then the first conductive microstructure is made of conductive silicone doped with conductive particles.

[0070] In some embodiments, the first electrode 230 is a multilayer conductor structure, as shown in FIG2B. The first electrode 230 includes a conductive layer 231 and a conductive microstructure layer 233 stacked sequentially. In this case, the conductive microstructure layer 233 includes a first conductive microstructure, and the first conductive microstructure is located on the side of the conductive microstructure layer 233 away from the conductive layer 231, that is, the first conductive microstructure is disposed on the side that contacts the first dielectric layer 240.

[0071] The conductive layer 231 is formed of a conductive material. For example, the conductive layer 231 may be formed of a metal (e.g., copper, silver, etc.), a flexible conductive silicone, or an indium tin oxide (ITO) conductive film.

[0072] The conductive microstructure layer 233 is a flexible conductor with a first conductive microstructure on its surface. The conductive microstructure layer 233 can be directly bonded to the conductive layer 231. For example, when the conductive layer 231 is in the form of conductive silicone, the conductive microstructure layer 233 and the conductive layer 231 can be directly bonded together.

[0073] In some embodiments, to further stabilize the structure of the first electrode 230, the first electrode 230 further includes a conductive connection layer 232. As shown in FIG2C, the first electrode 230 includes a conductive layer 231, a conductive connection layer 232, and a conductive microstructure layer 233 stacked sequentially.

[0074] The conductive connection layer 232 is used to connect the conductive layer 231 and the conductive microstructure layer 233. The conductive connection layer 232 is made of a conductive material. In some embodiments, the conductive connection layer 232 is formed of conductive silicone, conductive adhesive, conductive cloth, conductive tape, or conductive epoxy resin.

[0075] In some embodiments, the conductive layer 231, conductive connection layer 232, and conductive microstructure layer 233 of the first electrode 230 can be made of the same or different materials. For example, the conductive layer 231 is made of indium tin oxide (ITO) conductive film, the conductive connection layer 232 is made of conductive cloth, and the conductive microstructure layer 233 is made of conductive silicone. As another example, the conductive layer 231 and conductive connection layer 232 are made of conductive silicone, and the conductive microstructure layer 233 is made of conductive sponge with a metal coating or conductive foam material with a metal coating. Yet another example, the conductive layer 231, conductive connection layer 232, and conductive microstructure layer 233 are all made of conductive silicone.

[0076] In some embodiments, the conductive microstructure layer 233 is formed from a conductive sponge with a metal coating, a conductive foam material with a metal coating, or conductive silicone or conductive polydimethylsiloxane (PDMS) doped with conductive particles. Specifically, as shown in FIG2D, the conductive microstructure layer 233 includes a substrate 236 and a first conductive microstructure 234.

[0077] The substrate 236 is a structure in the conductive microstructure layer 233 used to support the first conductive microstructure 234.

[0078] In some embodiments, the first conductive microstructure 234 is formed from a conductive sponge or a conductive foam material with a metal-plated surface. For example, the first conductive microstructure 234 can be formed by electroplating an inert metal (e.g., nickel) onto the surface of a mesh-like polyester foam (or other sponge material).

[0079] In some embodiments, in order to facilitate deformation of the first conductive microstructure 234 when pressure is applied to the sensitive area of ​​the pressure sensor, resulting in significant changes in the contact area and equivalent dielectric constant between the microstructure and the first dielectric layer, thereby enhancing the sensitivity of the pressure sensor, the first conductive microstructure 234 includes a plurality of spaced flexible conductive protrusions, with pores formed between the protrusions. For example, as shown in FIG2D, the first conductive microstructure 234 includes a plurality of spaced flexible conductive protrusions (including flexible conductive protrusions 2341, 2342, 2343, 2344, 2345, 2346, 2347, and 2348); pores are formed between the flexible conductive protrusions (i.e., pores exist between adjacent flexible conductive protrusions), for example, a pore 2351 exists between flexible conductive protrusions 2341 and 2342.

[0080] In some embodiments, the flexible conductive protrusion is formed of conductive silicone or conductive polydimethylsiloxane (PDMS). In some embodiments, the flexible conductive protrusion is formed of conductive sponge with a metal-coated surface or conductive foam material with a metal-coated surface. In some embodiments, the shape of the flexible conductive protrusion is the zigzag shape shown in Figure 2D. In some embodiments, the shape of the flexible conductive protrusion can also be pyramidal, grooved, etc.

[0081] In some embodiments, the flexible conductive protrusions in the first conductive microstructure 234 are uniformly distributed. Uniform distribution means that the spacing (i.e., the width of any pore) between any adjacent flexible conductive protrusions in the first conductive microstructure 234 is equal or approximately equal. For example, as shown in FIG2D, the spacing between flexible conductive protrusions 2341 and 2342, between flexible conductive protrusions 2342 and 2343, ..., between flexible conductive protrusions 2347 and 2348 can all be equal to form uniformly distributed flexible conductive protrusions. In some embodiments, the spacing between the aforementioned flexible conductive protrusions is in the range of 1 μm to 500 μm; for example, the spacing between the aforementioned flexible conductive protrusions can be 5 μm, 50 μm, 100 μm, 200 μm, etc.

[0082] In some embodiments, the flexible conductive protrusions in the first conductive microstructure 234 are non-uniformly distributed. Non-uniform distribution means that the spacing between at least some adjacent flexible conductive protrusions in the first conductive microstructure 234 is unequal. For example, as shown in Figure 2D, the spacing between flexible conductive protrusions 2341 and 2342 is 5 μm, the spacing between flexible conductive protrusions 2342 and 2343 is 7 μm, the spacing between flexible conductive protrusions 2343 and 2344 is 5 μm, ..., and the spacing between flexible conductive protrusions 2347 and 2348 is 6 μm. As another example, the first conductive microstructure is formed by electroplating metal onto the surface of a mesh-like polyester foam (or other sponge material). Because the mesh or protrusions of the mesh-like polyester foam (or other sponge material) are non-uniformly distributed, the flexible conductive protrusions in the final first conductive microstructure are also non-uniformly distributed.

[0083] It is understandable that when the pressure sensor 200 is not subjected to external pressure, the surfaces of each flexible conductive protrusion can contact the first dielectric layer 240. At this time, it can be considered that each flexible conductive protrusion does not deform in the sensitive direction, and the contact area between the first conductive microstructure 234 and the first dielectric layer 240 is the sum of the contact areas between the ends of each flexible conductive protrusion (e.g., the end 23411 of the flexible conductive protrusion 2341) and the first dielectric layer 240, as shown in Figure 2D.

[0084] When the sensitive area of ​​the pressure sensor 200 is subjected to external pressure, each flexible conductive protrusion is squeezed in the sensitive direction, increasing the contact area between each flexible conductive protrusion and the first dielectric layer 240. At this time, the contact area between the first conductive microstructure 234 and the first dielectric layer 240 is the sum of the contact areas between each deformed flexible conductive protrusion and the first dielectric layer 240.

[0085] Under no external pressure, the ratio of the contact area between the first conductive microstructure 234 and the first dielectric layer 240 (i.e., the sum of the contact areas between the ends of each flexible conductive protrusion and the first dielectric layer 240) to the area of ​​the first dielectric layer 240 cannot be too large or too small. If the ratio is too large, the space available for the flexible conductive protrusions to deform will be too small, resulting in a small change in the contact area between the first conductive microstructure 234 and the first dielectric layer 240 under external pressure, thereby reducing the sensitivity of the pressure sensor 200. If the ratio is too small, the gaps between the flexible conductive protrusions will be too sparse. In this case, the change in capacitance of the pressure sensor 200 will be mainly dominated by the change in the distance between the first electrode 230 and the second electrode 250, i.e., the capacitance value C2 generated by the part of the first conductive microstructure 234 that is not in contact with the first dielectric layer 240 in formulas (1) to (3), resulting in a decrease in the sensitivity of the pressure sensor 200. Therefore, in some embodiments, in order to improve the sensitivity of the pressure sensor 200, the ratio of the contact area between the first conductive microstructure 234 and the first dielectric layer 240 to the area of ​​the first dielectric layer 240 is in the range of 1:10000 to 1:10 when not under external pressure.

[0086] Since the thickness and pore size of the flexible conductive protrusions can affect the degree of change in the contact area between the first electrode 230 (or the first conductive microstructure 234) and the first dielectric layer 240 under external pressure, in order to enable the pressure sensor 200 to have high sensitivity while having a small size for device miniaturization, in some embodiments, the thickness of the flexible conductive protrusions ranges from 1 μm to 500 μm, and the pore size of the flexible conductive protrusions ranges from 1 μm to 500 μm. In some embodiments, to ensure that the flexible conductive protrusions can generate sufficient deformation when the pressure sensor 200 is subjected to external pressure to ensure the sensitivity range of the pressure sensor 200 to external pressure, the thickness of the flexible conductive protrusions ranges from 10 μm to 400 μm, and the pore size of the flexible conductive protrusions ranges from 10 μm to 400 μm. In some embodiments, to ensure a large contact area between the first conductive microstructure 234 and the first dielectric layer 240 while providing sufficient deformation space for the flexible conductive protrusion to guarantee the sensitivity of the pressure sensor 200, the thickness of the flexible conductive protrusion ranges from 50 μm to 300 μm, and the size of the pores of the flexible conductive protrusion ranges from 20 μm to 300 μm. In some embodiments, the thickness of the flexible conductive protrusion ranges from 100 μm to 200 μm, and the size of the pores of the flexible conductive protrusion ranges from 50 μm to 200 μm. By limiting the thickness and pore size of the flexible conductive protrusion within the above ranges, a large contact area between the first conductive microstructure 234 and the first dielectric layer 240 is ensured while providing sufficient deformation space for the flexible conductive protrusion, thereby enabling the pressure sensor 200 to achieve a high level of sensitivity.

[0087] In some embodiments, to further avoid the gaps between the flexible conductive protrusions being too sparse and to improve the sensitivity of the pressure sensor 200, the size of the pores is less than or equal to the thickness of the flexible conductive protrusions. For example, the size of the pores is 100 μm and the thickness of the flexible conductive protrusions is 300 μm.

[0088] It is important to know that the thickness of the flexible conductive protrusion refers to its dimension in the thickness direction of the pressure sensor (as shown in Figure 2D, the dimension in the thickness direction of the zigzag flexible conductive protrusion). The size of the pore refers to its dimension in the width direction of the pressure sensor (as shown in Figure 2D, the dimension in the width direction of pore 2351). When the flexible conductive protrusions are not uniformly distributed, the size of each pore may be different; the size of the pore refers to the average size of all pores in the width direction as shown in Figure 2D.

[0089] In some embodiments of this specification, the first conductive microstructure can achieve variations in the contact area between the first electrode and the first dielectric layer. By making the first conductive microstructure from sponge or foam material, or by forming the flexible conductive protrusions from conductive silicone or conductive polydimethylsiloxane (PDMS), the manufacturing cost of the pressure sensor is reduced, facilitating mass production, while simultaneously improving the sensor's sensitivity. Furthermore, by limiting the thickness of the flexible conductive protrusions and the size of the pores, the first conductive microstructure can achieve both good stability and good deformation capability. For example, by setting the pore size to be less than or equal to the thickness of the flexible conductive protrusions, the sensitivity of the pressure sensor can be prevented from becoming too sparse. Furthermore, when the ratio of the contact area between the first conductive microstructure and the first dielectric layer to the area of ​​the first dielectric layer (hereinafter referred to as the first ratio) is too small, based on the above formula, the capacitance generated by the contact portion is too small, resulting in a decrease in the sensitivity of the pressure sensor. When the first ratio is too large (representing that the width of the gap between the flexible conductive protrusions is too small), the deformation of the flexible conductive protrusions under pressure will be limited, reducing the variable value of the first capacitor, which will also lead to a decrease in the sensitivity of the pressure sensor. Therefore, by limiting the size of the first ratio, the sensitivity of the pressure sensor can be kept at a higher level.

[0090] The first dielectric layer 240 is used to separate the first electrode 230 and the second electrode 250, thereby forming a first capacitor.

[0091] The first dielectric layer 240 is made of an insulating material. For example, the first dielectric layer 240 can be made of polyethylene terephthalate (PET), polyimide (PI), polydimethylsiloxane (PDMS), oxide ceramics, etc.

[0092] The thinner the first dielectric layer 240, 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 240 can reduce d, and C2 is inversely proportional to d. Therefore, the thinner the first dielectric layer 240, the larger C2 can be (and thus the larger C). In addition, the relative dielectric constant ε of C1 and the first dielectric layer 240... r1 Proportional, therefore, the dielectric constant ε of the first dielectric layer 240 is... 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.

[0093] 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 240 is less than 20 μm, and the relative permittivity of the first dielectric layer 240 is greater than 2. Preferably, the thickness of the first dielectric layer 240 is less than 2 μm, and the relative permittivity of the first dielectric layer is greater than 3.

[0094] In some embodiments, a dielectric microstructure 245 in contact with the first electrode 230 or the second electrode 250 is disposed on the first dielectric layer 240. For example, as shown in FIG. 2E, a dielectric microstructure 245 in contact with the second electrode 250 is disposed on the first dielectric layer 240. In this specification, a dielectric microstructure refers to a structure that is non-conductive and contains pores (or voids). The dielectric microstructure 245 includes a plurality of spaced flexible dielectric bumps. In some embodiments, the flexible dielectric bumps may have the same or similar structure and size as the flexible conductive bumps. For example, the flexible dielectric bumps may have the same zigzag structure as the flexible conductive bumps shown in FIG. 2D, and the thickness of both the flexible dielectric bumps and the flexible conductive bumps is in the range of 1 μm to 500 μm, etc.

[0095] When the first electrode 230 moves closer to the second electrode 250 in response to external pressure, it compresses the first dielectric layer 240. At this time, the flexible dielectric protrusions also deform. This deformation can change the contact area between the first dielectric layer 240 and the first electrode 230 or the second electrode 250, as well as the thickness of the first dielectric layer 240 itself, thereby changing the first capacitance. Furthermore, in order to improve the sensitivity of the pressure sensor 200, the dielectric microstructure 245 is arranged to contact the first conductive microstructure 235.

[0096] In some embodiments of this specification, the sensitivity of the pressure sensor can be improved by limiting the thickness and relative permittivity of the first dielectric layer; by providing a dielectric microstructure on the first dielectric layer that is similar to the first conductive microstructure and capable of elastic deformation, the change in the contact area between the first dielectric layer and the electrode (first electrode or second electrode) can be further increased, thereby improving the sensitivity of the pressure sensor.

[0097] The second electrode 250 may have the same or similar structure as the first electrode 230. For example, the second electrode 250 may be a single-layer conductor structure (e.g., the second electrode 250 may be a single-layer structure made of metal). As another example, the second electrode 250 may include a conductive layer and a conductive microstructure layer stacked sequentially. Yet another example, the second electrode 250 may include a conductive layer, a conductive connection layer, and a conductive microstructure layer stacked sequentially.

[0098] In some embodiments, to improve the sensitivity of the pressure sensor 200 by changing the contact area between the second electrode 250 and the first dielectric layer 240 under external pressure, as shown in FIG2F, a second conductive microstructure 255 in contact with the first dielectric layer 240 is arranged on the second electrode 250. The second conductive microstructure 255 may have the same or similar material and structure as the first conductive microstructure 234, which will not be described in detail here.

[0099] In some embodiments, to avoid mutual misalignment between the first dielectric layer 240 and the upper and lower electrodes (first electrode 230 or second electrode 250), the first conductive microstructure 234 and the second conductive microstructure 255 are formed of different materials. Specifically, one conductive microstructure is formed of a more easily deformable material, and the other conductive microstructure is formed of a material with higher contact resistance. For example, the first conductive microstructure 234 is formed of a conductive sponge or a conductive foam material with a metal coating on its surface, and the second conductive microstructure 255 is made of conductive silicone doped with conductive particles.

[0100] In some embodiments, the first conductive microstructure 234 and the second conductive microstructure 255 may have different structures. For example, the first conductive microstructure 234 may be a zigzag structure, and the second conductive microstructure 255 may be a pyramidal structure.

[0101] In some embodiments of this specification, by arranging a second conductive microstructure on the second electrode 250 that contacts the first dielectric layer 240, the change in the contact area between the first dielectric layer 240 and the electrode (first electrode 230 or second electrode 250) can be further increased, thereby improving the sensitivity of the pressure sensor 200. By using different materials to form the first and second conductive microstructures, the relative displacement between the first dielectric layer 240 and the electrode (first electrode or second electrode) during the use of the pressure sensor 200 can be effectively suppressed while maintaining a large rate of change in the contact area, thus ensuring the structural reliability and stability of the pressure sensor.

[0102] Figure 3A is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification; Figure 3B is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0103] In some embodiments, to improve the reliability and anti-interference capability of the pressure sensor, as shown in Figures 3A and 3B, the pressure sensor 300, based on the structure of the pressure sensor 200, further includes a third electrode 310. The third electrode 310 may have the same or similar material and structure as the first electrode 230 and / or the second electrode 250. To save costs and facilitate production, the third electrode 310 may not have conductive microstructures. Further explanation of the first electrode 230 / second electrode 250 can be found in Figures 2A-2D and their related descriptions.

[0104] The first electrode 230, the second electrode 250, and the third electrode 310 are arranged at intervals, with the two outermost electrodes grounded. For example, as shown in FIG3A, a first dielectric layer 240 is disposed between the first electrode 230 and the second electrode 250, and a second substrate 212 is disposed between the second electrode 250 and the third electrode 310. Specifically, the third electrode 310 is disposed on the side closer to the second electrode 250, and the two outermost electrodes are the first electrode 230 and the third electrode 310, both of which are grounded (the grounding wire is not shown in the figure). As another example, as shown in FIG3B, a first substrate 211 is disposed between the first electrode 230 and the third electrode 310, and a first dielectric layer 240 is disposed between the first electrode 230 and the second electrode 250. Specifically, the third electrode 310 is disposed on the side closer to the first electrode 230, and the two outermost electrodes are the second electrode 250 and the third electrode 310, both of which are grounded (the grounding wire is not shown in the figure).

[0105] In some embodiments, the pressure sensor 200 further includes a protective layer 320 for providing protection and support for the third electrode 310. As shown in Figures 3A and 3B, the protective layer 320 may be disposed outside the third electrode 310 and enclose the third electrode 310. The protective layer 320 is made of an insulating material, for example, a flexible insulating material such as a printed circuit board (PCB) or silicone.

[0106] In some embodiments of this specification, by providing a third electrode, interference from external electrical or magnetic signals on the internal sensing signal of the pressure sensor can be shielded, thereby improving the accuracy of the internal sensing signal of the pressure sensor.

[0107] Figure 4A is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification; Figure 4B is a structural schematic diagram of a pressure sensor according to some other embodiments of this specification.

[0108] In some embodiments, to simultaneously improve the sensitivity and anti-interference capability of the pressure sensor, the pressure sensor 200 further includes a second capacitor. The first capacitor and the second capacitor are arranged along the pressure-sensitive direction of the pressure sensor 200 (i.e., the thickness direction of the pressure sensor).

[0109] For example, as shown in FIG4A, the pressure sensor 400, based on the structure of the pressure sensor 200, further includes a third electrode 430 and a second dielectric layer 440 located between the second electrode 250 and the third electrode 430. The second electrode 250, the third electrode 430, and the second dielectric layer 440 located between the second electrode 250 and the third electrode 430 form the aforementioned second capacitor. The third electrode 430 includes a structure that is the same as or similar to that of the first electrode 230. For example, the third electrode 430 includes a conductive layer 431, a conductive connection layer 432, and a conductive microstructure layer 433. The first electrode 230 and the third electrode 430 located on the outer side are grounded (the grounding wire is not shown in the figure), and the second electrode 250 is connected to a data transmission line to transmit the sensing signal (electrical signal).

[0110] For example, as shown in Figure 4B, the pressure sensor 400, based on the structure of the pressure sensor 200, further includes a third electrode 430, a fourth electrode 450, and a second dielectric layer 440 located between the third electrode 430 and the fourth electrode 450. The third electrode 430, the fourth electrode 450, and the second dielectric layer 440 form the aforementioned second capacitor. The second capacitor, together with the first electrode 230, the second electrode 250, and the first dielectric layer 240, forms the first capacitor, which is arranged along the pressure-sensitive direction of the pressure sensor (i.e., the thickness direction of the pressure sensor shown in the figure).

[0111] Furthermore, in order to protect the second capacitor, the pressure sensor 400 also includes a third substrate 413 disposed outside the third electrode 430.

[0112] The third electrode 430, the fourth electrode 450, and the third substrate 413 may have the same or similar structures and materials as the first electrode 230, the second electrode 250, and the first substrate 211, respectively. Furthermore, the conductive layer 431, the conductive connection layer 432, and the conductive microstructure layer 433 included in the third electrode 430 may have the same or similar structures and materials as the conductive layer 231, the conductive connection layer 232, and the conductive microstructure layer 233 included in the first electrode 230. For further explanation of the first electrode 230, the second electrode 250, and the first substrate 211, please refer to Figures 2A to 2D and their related descriptions.

[0113] In some embodiments, to simultaneously improve the sensitivity and anti-interference capability of the pressure sensor, the second capacitor is connected in parallel with the first capacitor. In this case, the two outermost electrodes in the pressure-sensitive direction of the pressure sensor 400 are grounded, and the two middle electrodes are electrically connected. Exemplarily, as shown in FIG4B, the two outermost electrodes in the pressure-sensitive direction of the pressure sensor 400, namely the first electrode 230 and the third electrode 430, are grounded (the grounding wire is not shown in the figure), and the two middle electrodes, namely the second electrode 250 and the fourth electrode 450, are electrically connected (e.g., connected via a wire or conductive silicone, etc.).

[0114] In some embodiments, the first capacitor and the second capacitor can output electrical signals (sensing signals) independently. These signals can be further processed to determine external pressure. For example, as shown in Figure 4B, the two outermost electrodes in the pressure-sensitive direction of the pressure sensor 400, namely the first electrode 230 and the third electrode 430, are grounded (the grounding wire is not shown in the figure). In this case, the two middle electrodes, namely the second electrode 250 and the fourth electrode 450, are not connected. The further processing described above can involve summing, averaging, or performing other operations on the electrical signals generated by the first capacitor and the second capacitor respectively.

[0115] In some embodiments of this specification, two capacitors are formed in the pressure sensor, both of which can be affected by external pressure and output sensing signals. By grounding the outer electrode, interference from external electrical or magnetic signals on the internal sensing signal of the pressure sensor can be shielded, thereby improving the accuracy of the internal sensing signal of the pressure sensor. Furthermore, the two middle electrodes are electrically connected, in which case the two capacitors can also be regarded as a parallel structure (the total capacitance of the two capacitors is greater than that of a single capacitor), which improves the sensitivity of the pressure sensor. Alternatively, the sensing signals of the two capacitors can be output separately to avoid mutual interference between the two capacitors, thereby improving the sensitivity of the pressure sensor.

[0116] Figure 5A is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification; Figure 5B is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification; Figure 5C is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification; Figure 5D is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification; Figure 5E is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification; Figure 5F is a schematic diagram of the structure of a pressure sensor according to some other embodiments of this specification.

[0117] In some embodiments, to achieve simultaneous measurement of pressure location and magnitude, the pressure sensor includes multiple capacitors arranged in parallel. Specifically, the multiple capacitors are spaced apart along a direction perpendicular to the pressure-sensitive direction of the pressure sensor. Each capacitor corresponds one-to-one with its position and outputs a capacitance signal. Based on the sensing signal of the pressure sensor, it is determined which capacitor output the signal, and the position of the capacitor outputting the sensing signal is determined, thereby determining the location where external pressure is received.

[0118] For example, as shown in Figures 5A and 5B, the pressure sensor 500, based on the structure of the pressure sensor 200, further includes a third electrode 510, a fourth electrode 530, and a second dielectric layer 520 located between the third electrode 510 and the fourth electrode 530. The third electrode 510, the fourth electrode 530, and the second dielectric layer 520 form a second capacitor, which is spaced apart from the first capacitor formed by the first electrode 230, the second electrode 250, and the first dielectric layer 240 along a direction perpendicular to the pressure-sensitive direction of the pressure sensor (i.e., the width direction of the pressure sensor shown in the figures).

[0119] The third electrode 510 and the fourth electrode 530 may have the same or similar structure and material as the first electrode 230 and the second electrode 250, respectively. Furthermore, the conductive layer 511, conductive connection layer 512, and conductive microstructure layer 513 included in the third electrode 510 may have the same or similar structure and material as the conductive layer 231, conductive connection layer 232, and conductive microstructure layer 233 included in the first electrode 230. For more details regarding the first electrode 230 and the second electrode 250, please refer to Figures 2A to 2D and their related descriptions.

[0120] In some embodiments, as shown in FIG5A, the first capacitor and the second capacitor are separated by an air gap. In some embodiments, to improve the structural reliability of the pressure sensor, as shown in FIG5B, a support 540 is provided between the first capacitor and the second capacitor to space them apart.

[0121] It is understood that, since the first capacitor and the second capacitor are arranged at intervals along a direction perpendicular to the pressure-sensitive direction of the pressure sensor 500, the projections of the first capacitor and the second capacitor onto the pressure-sensitive direction of the pressure sensor 500 do not overlap. Based on this, the first capacitor and the second capacitor each have their own corresponding sensitive areas (as shown in Figures 5A to 5F, the first capacitor corresponds to sensitive area P1, and the second capacitor corresponds to sensitive area P2), allowing the first capacitor and the second capacitor to independently measure the external pressure at their respective locations. Based on this structure, the pressure sensor 500 can be used to detect sliding operations or other specific touch operations (detecting the above operations based on the position information of the two (or more) capacitors and the timing information of the generation of the sensing signal).

[0122] In some embodiments, to further simplify the structure and fabrication process of the pressure sensor, the first electrode 230 and the third electrode 510 are two different regions on a single electrode. That is, the first electrode 230 and the third electrode 510 are combined into a single electrode. In this case, the first capacitor and the second capacitor respectively output capacitance signals. Exemplarily, as shown in FIG5C, the fourth electrode 530 and the second electrode 250 of the pressure sensor 500 are located on the same side of the first electrode 230, the second electrode 250 and the fourth electrode 530 are respectively opposite to different regions on the first electrode 230, and a second dielectric layer 520 exists between the fourth electrode 530 and the first electrode 230 to form a second capacitor.

[0123] In some embodiments, the fourth electrode 530 and the second electrode 250 can be designed as rectangular electrodes placed side by side, or they can be configured as interdigitated electrodes or ring electrodes.

[0124] The output capacitance of the pressure sensor 500 is equivalent to the capacitance obtained by connecting the first capacitor and the second capacitor in series. This capacitance can be calculated based on the following formula (4):

[0125] Where C6 is the output capacitance value of pressure sensor 500; C 61 C is the capacitance value of the first capacitor; 62 This is the capacitance value of the second capacitor.

[0126] In some embodiments of this specification, by placing the fourth electrode and the second electrode on the same side of the first electrode, when connecting the pressure sensor to an external circuit, only the second and fourth electrodes need to be wired out, without requiring lead design for the first electrode. Since the second and fourth electrodes are both located on the same side of the capacitor, they can be easily connected to the same circuit board, thereby reducing the difficulty of wire design for the pressure sensor and significantly simplifying the structure and manufacturing process.

[0127] In some embodiments, the conductive layers of the first electrode 230 and the third electrode 510 are two different regions on the same conductive layer. For example, as shown in FIG5D, the conductive layer 231 of the first electrode 230 and the conductive layer 511 of the third electrode 510 are two different regions on the conductive layer 550. The conductive layer 550 can be made of metal, conductive silicone, conductive thin film, etc.

[0128] In some embodiments, the first electrode and the third electrode are electrically connected. For example, as shown in FIG5A or FIG5B, the first electrode 230 and the third electrode 510 can be electrically connected by a wire or conductive silicone. As another example, as shown in FIG5E or FIG5F, the first electrode 230 (or its conductive layer) and the third electrode 510 (or its conductive layer) are two different regions on the same electrode (or the same conductive layer). Further, a fifth electrode 560 is provided on the side of the second electrode 250 and the fourth electrode 530 opposite to the first electrode 230 and the third electrode 510. The first electrode 230, the third electrode 510, and the fifth electrode 560 are grounded (the grounding wire is not shown in the figures), as shown in FIG5E or FIG5F.

[0129] In some embodiments, as shown in FIG5E or FIG5F, the pressure sensor 500 further includes a protective layer 570 located outside the fifth electrode 560. The protective layer 570 is used to provide protection and support for the fifth electrode 560. The protective layer 570 can be made of a flexible insulating material such as a printed circuit board (PCB) or silicone.

[0130] In some embodiments of this specification, by arranging the second capacitor and the first capacitor at intervals along a direction perpendicular to the pressure-sensitive direction of the pressure sensor, the location and magnitude of the external pressure source can be measured simultaneously.

[0131] Figure 6A is a sensitivity test diagram of a pressure sensor according to some embodiments of this specification. As shown in Figure 6A, curve 610 represents the load (i.e., external pressure) curve, and curve 620 represents the capacitance value curve of the capacitor (e.g., the first capacitor) in the pressure sensor when the thickness of the flexible conductive protrusion of the pressure sensor is set to 200 μm and the substrate material is a flexible printed circuit board (FPC). As can be seen from Figure 6A, it exhibits excellent sensitivity and linearity within a pressure range of 350 g, and can accurately measure pressure changes within 1 g. Therefore, the pressure sensor provided in this specification can meet the human-computer interaction requirements of consumer electronics.

[0132] Figure 6B is a reliability test diagram of a pressure sensor according to some embodiments of this specification. As shown in Figure 6B, the pressure sensor exhibits excellent stability and reliability, maintaining stable performance even after up to 50,000 loading cycles.

[0133] 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.

Claims

1. A pressure sensor, comprising: A first capacitor is formed by a first electrode, a second electrode, and a first dielectric layer located between them, wherein, The first electrode has a first conductive microstructure in contact with the first dielectric layer. When the first electrode moves closer to the second electrode in response to external pressure, the first conductive microstructure deforms. The deformation changes the first capacitance of the first capacitor and generates a sensing signal that changes with the first capacitance.

2. The pressure sensor of claim 1, wherein, The first conductive microstructure includes a plurality of spaced flexible conductive protrusions, with pores formed between the flexible conductive protrusions.

3. The pressure sensor of claim 2, wherein, The first conductive microstructure is formed from a conductive sponge with a metal coating on its surface or a conductive foam material with a metal coating on its surface.

4. The pressure sensor of claim 2, wherein, The first electrode includes: a conductive layer, a conductive connection layer and a conductive microstructure layer stacked sequentially, wherein the first conductive microstructure is located on the side of the conductive microstructure layer away from the conductive layer.

5. The pressure sensor according to claim 4, wherein, The conductive layer is formed of flexible conductive silicone or indium tin oxide (ITO) conductive film; The conductive connection layer is formed of conductive silicone, conductive cloth, conductive tape, or conductive epoxy resin; and The conductive microstructure layer is formed by a conductive sponge with a metal coating, a conductive foam material with a metal coating, or a conductive silicone or conductive PDMS doped with conductive particles.

6. The pressure sensor according to claim 1, further comprising: The third electrode consists of the first electrode, the second electrode, and the third electrode arranged at intervals, with the two outermost electrodes grounded.

7. The pressure sensor according to claim 1, further comprising: The second capacitor is formed by a third electrode, a fourth electrode, and a second dielectric layer located between the third electrode and the fourth electrode. The first capacitor and the second capacitor are arranged along the pressure-sensitive direction of the pressure sensor.

8. The pressure sensor of claim 7, wherein, The two outermost electrodes in the pressure-sensitive direction are grounded, and the two middle electrodes are electrically connected.

9. The pressure sensor according to claim 1, further comprising: The second capacitor is formed by a third electrode, a fourth electrode, and a second dielectric layer located between the third electrode and the fourth electrode. The second capacitor and the first capacitor are arranged at intervals along a direction perpendicular to the pressure-sensitive direction of the pressure sensor.

10. The pressure sensor according to claim 1, further comprising: The third electrode is located on the same side of the first electrode as the second electrode. The second electrode and the third electrode are respectively opposite to different regions on the first electrode. A second dielectric layer exists between the third electrode and the first electrode to form a second capacitor.

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