Flexible pressure sensor

Abstract

The application discloses a flexible pressure sensor, which comprises a flexible base, a first electrode layer, a second electrode layer and at least one silicon dioxide dielectric layer, wherein the flexible base is provided with a containing space; the first electrode layer is arranged in the containing space; the second electrode layer is arranged in the containing space and is arranged opposite to and spaced from the first electrode layer; and the silicon dioxide dielectric layer is arranged between the first electrode layer and the second electrode layer, and each silicon dioxide dielectric layer comprises a plurality of dielectric parts, and the mass fraction of silicon dioxide of two adjacent dielectric parts is different. Thus, the flexible pressure sensor of the application realizes gradient distribution of dielectric performance in space by arranging the silicon dioxide dielectric layer with a plurality of dielectric parts with different mass fractions of silicon dioxide between the electrode layers, effectively solves the problem of limited range caused by uniformity of the dielectric layer in the prior art, and thus realizes a synergistic breakthrough of high range and high sensitivity.

Description

Technical Field

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

[0002] With the rapid development of flexible electronics technology, flexible pressure sensors, due to their advantages such as being lightweight, thin, flexible, and adaptable, are widely used in various fields such as smart wearable devices, health monitoring, robotic tactile sensing, and battery status monitoring. Among them, capacitive flexible pressure sensors have become one of the current research hotspots due to their advantages such as simple structure, fast response speed, and low power consumption.

[0003] However, in related technologies, most flexible pressure sensors use a single material and a dielectric layer of uniform thickness, which results in a small measuring range for the flexible sensor. Utility Model Content

[0004] This application provides a flexible pressure sensor that can solve at least one of the above-mentioned technical problems.

[0005] This application provides a flexible pressure sensor, including:

[0006] A flexible substrate, wherein the flexible substrate is provided with a receiving space;

[0007] A first electrode layer is disposed within the accommodating space;

[0008] A second electrode layer, wherein the second electrode layer is disposed within the receiving space and is opposite to and spaced apart from the first electrode layer; and

[0009] At least one silicon dioxide dielectric layer is disposed between the first electrode layer and the second electrode layer. Each silicon dioxide dielectric layer includes a plurality of dielectric portions, and the mass fraction of silicon dioxide in two adjacent dielectric portions is different.

[0010] In some embodiments, the plurality of dielectric portions include a first dielectric portion, a second dielectric portion, and a third dielectric portion connected in sequence, wherein the second dielectric portion is disposed around the edge of the first dielectric portion, the third dielectric portion is disposed around the edge of the second dielectric portion, and the third dielectric portion is located on the side of the second dielectric portion opposite to the first dielectric portion.

[0011] In some embodiments, the silicon dioxide mass fraction of the first dielectric portion, the silicon dioxide mass fraction of the second dielectric portion, and the silicon dioxide mass fraction of the third dielectric portion decrease sequentially.

[0012] In some embodiments, the mass of silicon dioxide in the first dielectric portion is 0.7g; the mass of silicon dioxide in the second dielectric portion is 0.5g; and the mass of silicon dioxide in the third dielectric portion is 0.3g.

[0013] In some embodiments, the thickness of the first dielectric portion, the thickness of the second dielectric portion, and the thickness of the third dielectric portion decrease sequentially.

[0014] In some embodiments, the thickness of the first dielectric portion is 190-210 μm; the thickness of the second dielectric portion is 140-160 μm; and the thickness of the third dielectric portion is 90-110 μm.

[0015] In some embodiments, the flexible substrate includes a first flexible base layer and a second flexible base layer, the first flexible base layer and the second flexible base layer being disposed opposite to each other and cooperating to form the accommodating space, the first electrode layer being disposed on the first flexible base layer, and the second electrode layer being disposed on the second flexible base layer.

[0016] In some embodiments, both the first flexible substrate and the second flexible substrate are polyimide sheets.

[0017] In some embodiments, the flexible pressure sensor further includes an adhesive layer connected between the first flexible substrate and the second flexible substrate.

[0018] In some embodiments, the adhesive layer is arranged in a ring shape and located at the edge of the first flexible base layer.

[0019] The flexible pressure sensor provided in this application includes a flexible substrate, a first electrode layer, a second electrode layer, and at least one silicon dioxide dielectric layer. The flexible substrate has a receiving space; the first electrode layer is disposed within the receiving space; the second electrode layer is disposed within the receiving space and is opposite to and spaced apart from the first electrode layer; the silicon dioxide dielectric layer is disposed between the first electrode layer and the second electrode layer, and each silicon dioxide dielectric layer includes multiple dielectric portions, with adjacent dielectric portions having different silicon dioxide mass fractions. Thus, the flexible pressure sensor of this application achieves a spatial gradient distribution of dielectric properties by providing silicon dioxide dielectric layers with multiple dielectric portions having different silicon dioxide mass fractions between the electrode layers. This helps improve the response capability of the flexible pressure sensor in different pressure ranges, thereby enhancing the linearity and sensitivity of the flexible pressure sensor over a wide pressure range. Compared to traditional flexible pressure sensors using a single dielectric parameter, the flexible pressure sensor of this application effectively solves the range limitation problem caused by the uniformity of the dielectric layer in the prior art through the differentiated design of adjacent dielectric portions, thereby achieving a synergistic breakthrough in high range and high sensitivity. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the exploded structure of the flexible pressure sensor in the embodiments of this application.

[0022] Figure 2 This is a schematic diagram of the exploded structure of a flexible pressure sensor in another embodiment of this application.

[0023] Figure 3 This is a cross-sectional schematic diagram of a flexible pressure sensor in another embodiment of this application.

[0024] Figure 4 This is a diagram showing the capacitive response curves of the flexible pressure sensor under different pressures in the embodiments of this application.

[0025] Figure 5 This is a schematic diagram showing the linearity test results of the flexible pressure sensor in the pressure range of 50-200 kPa in the embodiments of this application.

[0026] Figure 6 This is a schematic diagram showing the test results of the response time and recovery time of the flexible pressure sensor in the embodiments of this application.

[0027] Figure 7 This is a schematic diagram showing the test results of the flexible pressure sensor at the lowest pressure detection limit in the embodiments of this application.

[0028] Explanation of icon numbers:

[0029] 10. Flexible pressure sensor; 100. Flexible substrate; 101. Accommodation space; 110. First flexible base layer; 120. Second flexible base layer; 200. First electrode layer; 300. Second electrode layer; 400. Silicon dioxide dielectric layer; 410. Dielectric part; 420. First dielectric part; 430. Second dielectric part; 440. Third dielectric part; 500. Adhesive layer.

[0030] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0032] Where the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0033] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] With the rapid development of flexible electronics technology, flexible pressure sensors, due to their advantages such as being lightweight, thin, flexible, and adaptable, are widely used in various fields such as smart wearable devices, health monitoring, robotic tactile sensing, and battery status monitoring. Among them, capacitive flexible pressure sensors have become one of the current research hotspots due to their simple structure, fast response speed, and low power consumption. However, in related technologies, most flexible pressure sensors use a single material and a dielectric layer of uniform thickness, resulting in a relatively small measuring range.

[0036] In view of this, please refer to Figures 1 to 3 This application provides a flexible pressure sensor 10, which includes a flexible substrate 100, a first electrode layer 200, a second electrode layer 300, and at least one silicon dioxide dielectric layer 400. The flexible substrate 100 has a receiving space 101. The first electrode layer 200 is disposed in the receiving space 101. The second electrode layer 300 is disposed in the receiving space 101 and is opposite to and spaced apart from the first electrode layer 200. The silicon dioxide dielectric layer 400 is disposed between the first electrode layer 200 and the second electrode layer 300. Each silicon dioxide dielectric layer 400 includes a plurality of dielectric portions 410, and the mass fraction of silicon dioxide in two adjacent dielectric portions 410 is different.

[0037] Thus, the flexible pressure sensor 10 of this application achieves a spatial gradient distribution of dielectric properties by setting a silicon dioxide dielectric layer 400 with multiple dielectric portions 410 of different silicon dioxide mass fractions between the electrode layers. This helps to improve the response capability of the flexible pressure sensor 10 in different pressure ranges, thereby enhancing the linearity and sensitivity of the flexible pressure sensor 10 over a wide pressure range. Compared with the traditional flexible pressure sensor 10 using a single dielectric parameter, the flexible pressure sensor 10 of this application effectively solves the problem of range limitation caused by the uniformity of dielectric layers in the prior art through the differentiated design of two adjacent dielectric portions 410, thereby achieving a synergistic breakthrough in high range and high sensitivity.

[0038] Furthermore, the flexible pressure sensor 10 incorporates multiple dielectric sections 410, enabling different regions to exhibit varying deformation responses and dielectric property changes when subjected to pressure, thus forming a multi-stage pressure sensing mechanism. This zoned response mechanism not only enhances the detection accuracy of the flexible pressure sensor 10 in the low-pressure range but also maintains good linear output in the high-pressure range, avoiding the signal saturation phenomenon that commonly occurs in traditional sensors under high pressure.

[0039] In addition, the silicon dioxide dielectric layer 400 is mainly made of silicon dioxide, which helps to improve the mechanical strength and stability of the dielectric layer, thereby helping to extend the service life of the flexible pressure sensor 10 and enhance the reliability of the flexible pressure sensor 10 in complex environments.

[0040] The flexible substrate 100 is made of a flexible material, such as polyimide (PI), polyethylene terephthalate (PET), or polyurethane (PU), and has an internal accommodating space 101 for accommodating the first electrode layer 200, the second electrode layer 300, and the silicon dioxide dielectric layer 400. The first electrode layer 200 and the second electrode layer 300 are respectively disposed in the upper and lower regions of the accommodating space 101, and are arranged opposite to each other and spaced apart, forming the basic unit of the capacitor structure. The first electrode layer 200 and the second electrode layer 300 can be made of materials with good conductivity and flexibility, such as conductive silver paste, carbon paste, graphene materials, or conductive polymers, and are prepared by processes such as screen printing, spraying, or deposition.

[0041] The silicon dioxide dielectric layer 400 disposed between the two electrode layers consists of multiple dielectric portions 410, each distributed along the plane of the electrode layer, with different mass fractions of silicon dioxide in adjacent dielectric portions 410. For example, the dielectric portions 410 in the central region have a higher silicon dioxide content, resulting in a larger dielectric constant and higher stiffness; while the dielectric portions 410 in the outer peripheral region have a lower silicon dioxide content, exhibiting better flexibility and compressibility. This allows the dielectric portions 410 in different regions to undergo different degrees of deformation and dielectric property changes when the sensor is subjected to external pressure, thereby achieving a multi-stage response to pressure signals.

[0042] In practice, the silicon dioxide dielectric layer 400 can be formed through multiple screen printing processes. First, a base dielectric material is printed on the surface of the electrode layer (e.g., the first electrode layer 200 or the second electrode layer 300). Then, according to design requirements, composite dielectric materials containing different mass fractions of silicon dioxide are sequentially printed, ultimately forming a dielectric structure with a gradient distribution. The thickness, area, and silicon dioxide concentration of each dielectric section 410 can be optimized and adjusted according to actual application requirements to achieve the best match between sensitivity and linearity.

[0043] After the flexible pressure sensor 10 is assembled, external pressure is applied to the surface of the flexible substrate 100, causing deformation of the silicon dioxide dielectric layer 400. This changes the spacing between the first electrode layer 200 and the second electrode layer 300, and simultaneously alters the polarization state of the dielectric material, resulting in a change in the overall capacitance value. By acquiring the capacitance change signal through an external circuit and establishing a correspondence with the pressure magnitude, high-precision pressure detection can be achieved.

[0044] In some embodiments, the plurality of dielectric portions 410 include a first dielectric portion 420, a second dielectric portion 430, and a third dielectric portion 440 connected in sequence. The second dielectric portion 430 is disposed around the edge of the first dielectric portion 420, and the third dielectric portion 440 is disposed around the edge of the second dielectric portion 430, and the third dielectric portion 440 is located on the side of the second dielectric portion 430 opposite to the first dielectric portion 420. That is, the first dielectric portion 420, the second dielectric portion 430, and the third dielectric portion 440 are stacked in sequence, with the second dielectric portion 430 protruding from the edge of the first dielectric portion 420 and the third dielectric portion 440 protruding from the edge of the second dielectric portion 430.

[0045] In this design, the first dielectric portion 420 is located in the central region of the sensor, serving as the core sensing unit for pressure response. The second dielectric portion 430 surrounds the edge of the first dielectric portion 420, forming an intermediate pressure response region. The third dielectric portion 440 further surrounds the outer side of the second dielectric portion 430 and is located at the end of the second dielectric portion 430 opposite to the first dielectric portion 420, forming an outer pressure buffer and extended response region. These three components are concentrically distributed along the plane of the electrode layer, forming a composite dielectric structure with a spatial gradient.

[0046] The silica mass fraction in the first dielectric section 420, the second dielectric section 430, and the third dielectric section 440 decreases sequentially. Specifically, the first dielectric section 420 has the highest silica content, exhibiting a large dielectric constant and high mechanical stiffness; the second dielectric section 430 has a moderate silica content, balancing rigidity and deformation capability; and the third dielectric section 440 has the lowest silica content, demonstrating superior flexibility and compressibility. Through this design, during the application of external pressure, different regions will gradually deform according to the pressure magnitude: in the low-pressure stage, the central first dielectric section 420 primarily dominates the response, its high dielectric constant significantly improving the sensor's initial sensitivity; as the pressure increases, the second dielectric section 430 begins to participate in the response, providing a transitional linear output; when the pressure further increases, the more flexible third dielectric section 440 undergoes significant deformation, effectively absorbing stress concentration caused by high pressure, preventing signal saturation, and thus achieving stable detection over a wide measurement range.

[0047] During manufacturing, each dielectric section 410 can be prepared in layers using a screen printing process. First, the first dielectric section 420 is printed on the electrode surface. Then, the screen with a ring pattern is replaced, and the second dielectric section 430 and the third dielectric section 440 are printed sequentially. Each layer uses a composite material solution containing a different mass fraction of silica to ensure good interfacial bonding and continuity between different regions. The final silica dielectric layer 400 not only has partitioned characteristics in its physical structure but also achieves spatial gradient control of material properties.

[0048] In some embodiments, the silicon dioxide mass fraction of the first dielectric portion 420, the silicon dioxide mass fraction of the second dielectric portion 430, and the silicon dioxide mass fraction of the third dielectric portion 440 decrease sequentially.

[0049] Specifically, the first dielectric part 420 is mainly located in the central region of the flexible pressure sensor 10, where the silicon dioxide mass fraction is the highest, giving this region a high dielectric constant and large mechanical stiffness; the second dielectric part 430 mainly surrounds the first dielectric part 420, and its silicon dioxide mass fraction is lower than that of the first dielectric part 420, exhibiting moderate dielectric properties and good deformation adaptability; the third dielectric part 440 is mainly disposed on the outermost layer, and its silicon dioxide mass fraction is the lowest, with low rigidity and high compressibility, which can generate large deformation under applied high pressure, effectively alleviating stress concentration and maintaining the linear change of the output signal.

[0050] The gradient distribution design of the aforementioned mass fraction enables the flexible pressure sensor 10 to exhibit differentiated response mechanisms across different pressure ranges. Under low pressure, the first dielectric part 420 in the central region preferentially undergoes polarization change due to its higher dielectric constant, resulting in a significant increase in capacitance and thus enhancing the sensor's initial sensitivity. As the pressure gradually increases, the second dielectric part 430 begins to participate in the response, with its dielectric properties and mechanical behavior playing a transitional role, ensuring that the output of the flexible pressure sensor 10 maintains a good linear relationship. When the applied pressure further increases, the third dielectric part 440 undergoes significant compression deformation due to its lower rigidity, absorbing excess stress and preventing the flexible pressure sensor 10 from entering a response saturation state, thereby expanding the overall detection range.

[0051] In terms of material preparation, the performance of each dielectric part 410 can be controlled by adjusting the proportion of silicon dioxide added to the composite dielectric material. For example, the first dielectric part 420 uses a high-concentration silicon dioxide composite material, the second dielectric part 430 uses a medium-concentration material, and the third dielectric part 440 uses a low-concentration material. These materials are sequentially deposited on the electrode surface using a screen printing process and then cured to form a stable structure. The thickness, area, and silicon dioxide content of each dielectric part 410 can be flexibly adjusted according to actual application requirements to achieve optimal matching of sensitivity, range, and linearity.

[0052] In some embodiments, the silicon dioxide in the first dielectric portion 420 has a mass of 0.7g; the silicon dioxide in the second dielectric portion 430 has a mass of 0.5g; and the silicon dioxide in the third dielectric portion 440 has a mass of 0.3g.

[0053] Specifically, the first dielectric part 420 uses a composite material with a silicon dioxide mass of 0.7g, which gives this region a high dielectric constant and strong rigidity. Under low pressure, it can generate obvious polarization effect and deformation response, significantly improving the sensitivity of the flexible pressure sensor 10 in the low pressure range. The second dielectric part 430 uses a material with a silicon dioxide mass of 0.5g, which has a moderate dielectric constant and mechanical strength. Under moderate pressure, it begins to participate in capacitance change and plays a role in the linear transition of signal output. The third dielectric part 440 uses a material with a silicon dioxide mass of 0.3g, which has low rigidity and high compressibility. Under high pressure, it undergoes large deformation, effectively absorbing stress and preventing the sensor from entering the response saturation state, thereby extending the overall detection range.

[0054] The selection of the three silica qualities mentioned above is based on extensive experimental verification and performance optimization, ensuring that the sensor possesses excellent linearity and stability over a wide pressure range. During manufacturing, each dielectric component 410 is sequentially formed using a screen printing process. Each dielectric component 410 employs a composite dielectric paste containing the appropriate mass of silica, which, after coating, drying, and curing, forms a multilayer dielectric structure with a complete structure and clear interfaces. By precisely controlling the proportions and printing thickness of each layer, spatially precise control of the dielectric properties is achieved.

[0055] In some embodiments, the thickness of the first dielectric portion 420, the thickness of the second dielectric portion 430, and the thickness of the third dielectric portion 440 decrease sequentially.

[0056] Specifically, the first dielectric section 420 has the largest thickness, followed by the second dielectric section 430, and the third dielectric section 440 has the smallest thickness. This design not only matches the variation in the silicon dioxide mass fraction in each dielectric section 410, but also further enhances the response characteristics and structural adaptability of the flexible pressure sensor 10 in different pressure ranges.

[0057] Among them, the first dielectric part 420, due to its large thickness, can provide sufficient deformation space and polarization change capability under low pressure, thereby enhancing the capacitance change rate in the initial stage and improving the sensitivity of the sensor; the second dielectric part 430, with moderate thickness, begins to undergo significant compression deformation under medium pressure conditions, allowing the output signal of the flexible pressure sensor 10 to enter a stable transition stage, which helps maintain a good linear response; the third dielectric part 440, due to its smallest thickness, is more likely to undergo local compression under high pressure, playing a role in buffering stress concentration and preventing signal saturation, thereby effectively expanding the detection upper limit of the flexible pressure sensor 10.

[0058] In some embodiments, the thickness of the first dielectric portion 420 is 190-210 μm; the thickness of the second dielectric portion 430 is 140-160 μm; and the thickness of the third dielectric portion 440 is 90-110 μm.

[0059] The first dielectric part 420 has a large thickness range (190–210 μm), providing it with ample compression space and high initial dielectric response capability. Under low pressure, it can produce significant deformation and polarization changes, thereby improving the sensor's initial sensitivity. The thickness of the second dielectric part 430 is controlled between 140–160 μm. It begins to compress effectively under medium pressure, allowing the sensor output signal to enter the linear transition stage, which helps maintain the consistency and stability of the overall response. The third dielectric part 440 has the smallest thickness, set in the range of 90–110 μm. Under high pressure, it is more likely to undergo local compression deformation, which plays a role in buffering stress concentration and preventing signal saturation, thereby effectively extending the upper limit of the sensor's measurement range.

[0060] The selection of the aforementioned thickness parameters was verified and optimized through systematic experiments, taking into account material utilization, manufacturing process feasibility, and the overall performance requirements of the sensor. In the actual fabrication process, by precisely controlling the paste coating thickness and subsequent curing conditions in the screen printing process, the thickness of each dielectric 410 section can be accurately controlled, ensuring clear interlayer interfaces and structural stability, while avoiding problems such as response hysteresis due to excessive thickness or insufficient mechanical strength due to insufficient thickness.

[0061] In some embodiments, the flexible substrate 100 includes a first flexible base layer 110 and a second flexible base layer 120, the first flexible base layer 110 and the second flexible base layer 120 being disposed opposite to each other and cooperating to form the accommodating space 101, the first electrode layer 200 being disposed on the first flexible base layer 110, and the second electrode layer 300 being disposed on the second flexible base layer 120.

[0062] The first flexible base layer 110 serves as the basic structure supporting the first electrode layer 200 and is located in the lower region of the sensor; the second flexible base layer 120 serves as the supporting structure supporting the second electrode layer 300 and is located in the upper region of the sensor. The two flexible base layers are fixedly connected by means of bonding, hot pressing, or integral molding, so that the entire flexible pressure sensor 10 can maintain uniform stress and coordinated deformation when subjected to external pressure.

[0063] Both the first flexible substrate 110 and the second flexible substrate 120 are made of materials with good flexibility and mechanical stability, such as polyimide (PI), polyethylene terephthalate (PET), polyurethane (PU), and other polymer films. These materials not only have excellent bending adaptability, but also can achieve good compatibility with electrode materials and composite dielectric materials, which helps to improve the reliability of the sensor under complex curved surfaces or dynamic load conditions.

[0064] In practical applications, the first electrode layer 200 is directly formed on the inner surface of the first flexible substrate 110 through screen printing, spraying, or deposition processes. The second electrode layer 300 is disposed at the corresponding position on the second flexible substrate 120 in the same manner, ensuring that the two electrode layers maintain precise alignment and a certain initial spacing after assembly. The silicon dioxide dielectric layer 400 is disposed between the two electrodes and serves as a key sensing unit for capacitance changes. Its multi-dielectric section 410 structure can achieve zoned response based on pressure distribution characteristics, thereby improving the overall performance of the sensor.

[0065] In some embodiments, both the first flexible substrate 110 and the second flexible substrate 120 are polyimide sheets.

[0066] Polyimide is a high-performance polymer material with excellent thermal stability, mechanical strength and chemical resistance, as well as good flexibility and processability, making it an ideal substrate material widely used in flexible electronic devices.

[0067] Using polyimide sheets as the main component of the flexible substrate 100 not only provides a stable support platform for the first electrode layer 200 and the second electrode layer 300, but also endows the entire flexible pressure sensor 10 with good bending adaptability and structural durability. When subjected to external pressure or deformation, the polyimide substrate can deform in tandem with the dielectric layer and electrode layer, avoiding interface delamination or functional failure caused by material mismatch, thereby improving the reliability of the sensor in complex environments.

[0068] In actual manufacturing, polyimide sheets are typically used in the form of thin films with a thickness of 50–200 μm, which meets the requirements of lightweight design while possessing sufficient mechanical strength to withstand repeated bending and compression. The first electrode layer 200 is formed directly on the inner surface of the first flexible substrate 110 through screen printing, spraying, or other microfabrication processes, while the second electrode layer 300 is disposed at the corresponding position on the second flexible substrate 120, ensuring precise alignment and stable spacing between the two electrodes. The silicon dioxide dielectric layer 400 is disposed between the two electrodes, serving as the core area for pressure sensing. Its multi-dielectric section 410 structure can achieve zoned response according to different pressure levels, significantly improving the sensitivity and linearity of the flexible pressure sensor 10.

[0069] In some embodiments, the flexible pressure sensor 10 further includes an adhesive layer 500 connected between the first flexible base layer 110 and the second flexible base layer 120.

[0070] The adhesive layer 500 is disposed between the first flexible base layer 110 and the second flexible base layer 120, and fixes the two together to form a complete flexible substrate 100 structure. The adhesive layer 500 not only plays a role in structural fixation and encapsulation protection, but also provides good interface support and mechanical adaptation for the various functional layers inside the sensor, ensuring that the sensor can achieve stable and repeatable pressure sensing when subjected to external pressure.

[0071] The adhesive layer 500 is made of a material with flexibility and good adhesion, such as double-sided tape, hot melt adhesive film, pressure-sensitive adhesive, or UV-curable adhesive. Its thickness and adhesive strength can be selected and adjusted according to actual application requirements to balance the sensor's sealing, structural integrity, and flexibility. During assembly, the adhesive layer 500 is precisely cut and attached between the first flexible base layer 110 and the second flexible base layer 120, surrounding the electrode layer and dielectric layer to form a closed receiving space 101, effectively preventing displacement, detachment, or interference from the external environment of the internal functional layers.

[0072] In addition, the design of the adhesive layer 500 provides the flexible pressure sensor 10 with good stress buffering capability. When subjected to complex deformation such as bending, stretching or compression, it can coordinate the relative movement between the first flexible base layer 110 and the second flexible base layer 120, avoid local stress concentration caused by material stiffness differences, thereby improving the stability and service life of the sensor in dynamic use environments.

[0073] By introducing the adhesive layer 500, the overall assembly process of the flexible pressure sensor 10 is simplified, and the manufacturing efficiency and yield are improved. At the same time, the device's sealing performance and environmental adaptability are enhanced in the structural design. It is particularly suitable for applications with high requirements for long-term stability and reliability, such as battery expansion monitoring, flexible electronic skin, and smart wearable devices.

[0074] In some embodiments, the adhesive layer 500 is arranged in a ring shape and located at the edge of the first flexible base layer 110.

[0075] This ring arrangement not only achieves effective connection and encapsulation of the flexible substrate 100, but also preserves a complete accommodating space 101 in the central area of ​​the sensor to facilitate the functional realization of the electrode layer and the dielectric layer.

[0076] The annular adhesive layer 500 is distributed around the core functional area of ​​the sensor. While ensuring sufficient adhesion between the first flexible base layer 110 and the second flexible base layer 120, it avoids direct coverage of the central pressure sensing area, thereby preventing the accuracy of capacitance changes from being affected by the adhesive material. Furthermore, this design helps to create a relatively enclosed internal environment, effectively isolating external dust, moisture, and other interference factors, improving the stability and lifespan of the flexible pressure sensor 10 under complex operating conditions.

[0077] During manufacturing, the adhesive layer 500 is pre-cut or molded into a ring structure and fixed to the edge area of ​​the first flexible base layer 110 by bonding, hot pressing, or UV curing. Subsequently, the second flexible base layer 120, which carries the second electrode layer 300, is aligned and pressed onto the adhesive layer 500 to ensure that the functional layers of the entire sensor maintain precise alignment after assembly, while the overall structure has good sealing performance and mechanical consistency.

[0078] Based on the above implementation, under low pressure, the flexible pressure sensor 10 is primarily controlled by the first dielectric part 420 in the central region, whose high dielectric constant and large thickness significantly improve the sensitivity in the initial stage. As the pressure increases, the second dielectric part 430 begins to participate in the response, playing a linear transition role. When the pressure further increases, the low-rigidity third dielectric part 440 undergoes significant compression deformation, absorbing excess stress and preventing the sensor from entering a saturation state, thereby achieving stable output over a wide range. This multi-stage response mechanism effectively solves the problem in traditional flexible pressure sensors 10 where a single dielectric parameter makes it difficult to simultaneously achieve high range and high sensitivity. Figure 4 and Figure 5 As shown, according to the test results, the flexible pressure sensor 10 of this application can achieve high-sensitivity detection in the range of 0-50 kPa, with a minimum detection limit of 13.73 Pa; in the range of 50-200 kPa, the linearity remains above 99%, and the capacitive response is improved by about 2-3 times. Figure 6 As shown, the response time of the flexible pressure sensor is approximately 410 ms, and the recovery time of the flexible pressure sensor 10 is approximately 340 ms. Figure 7 As shown, the minimum pressure detection limit of the flexible pressure sensor 10 is 14.26 Pa, which gives the flexible pressure sensor 10 high sensitivity.

[0079] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0080] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flexible pressure sensor, characterized in that, include: A flexible substrate, wherein the flexible substrate is provided with a receiving space; A first electrode layer is disposed within the accommodating space; A second electrode layer, wherein the second electrode layer is disposed within the receiving space and is opposite to and spaced apart from the first electrode layer; and At least one silicon dioxide dielectric layer is disposed between the first electrode layer and the second electrode layer. Each silicon dioxide dielectric layer includes a plurality of dielectric portions, and the mass fraction of silicon dioxide in two adjacent dielectric portions is different.

2. The flexible pressure sensor according to claim 1, characterized in that, The plurality of dielectric portions include a first dielectric portion, a second dielectric portion, and a third dielectric portion connected in sequence, wherein the second dielectric portion is disposed around the edge of the first dielectric portion, the third dielectric portion is disposed around the edge of the second dielectric portion, and the third dielectric portion is located on the side of the second dielectric portion opposite to the first dielectric portion.

3. The flexible pressure sensor according to claim 2, characterized in that, The silicon dioxide mass fraction of the first dielectric part, the silicon dioxide mass fraction of the second dielectric part, and the silicon dioxide mass fraction of the third dielectric part decrease sequentially.

4. The flexible pressure sensor according to claim 3, characterized in that, The mass of silicon dioxide in the first dielectric part is 0.7g; the mass of silicon dioxide in the second dielectric part is 0.5g; and the mass of silicon dioxide in the third dielectric part is 0.3g.

5. The flexible pressure sensor according to claim 2, characterized in that, The thickness of the first dielectric portion, the thickness of the second dielectric portion, and the thickness of the third dielectric portion decrease sequentially.

6. The flexible pressure sensor according to claim 5, characterized in that, The thickness of the first dielectric part is 190-210 μm; the thickness of the second dielectric part is 140-160 μm; and the thickness of the third dielectric part is 90-110 μm.

7. The flexible pressure sensor according to any one of claims 1 to 6, characterized in that, The flexible substrate includes a first flexible base layer and a second flexible base layer. The first flexible base layer and the second flexible base layer are disposed opposite to each other and cooperate to form the accommodating space. The first electrode layer is disposed on the first flexible base layer and the second electrode layer is disposed on the second flexible base layer.

8. The flexible pressure sensor according to claim 7, characterized in that, Both the first flexible substrate and the second flexible substrate are polyimide sheets.

9. The flexible pressure sensor according to claim 7, characterized in that, The flexible pressure sensor also includes an adhesive layer, which is connected between the first flexible base layer and the second flexible base layer.

10. The flexible pressure sensor according to claim 9, characterized in that, The adhesive layer is arranged in a ring shape and is located at the edge of the first flexible base layer.

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