Pressure sensor

Abstract

The invention belongs to the field of pressure sensors, and discloses a pressure sensor, which comprises a dielectric layer, and a conductive layer and an electrode layer which are sequentially arranged on the surfaces of the two sides of the dielectric layer. Wherein the dielectric layer is a piezoelectric film layer subjected to polarization treatment; the conductive layer comprises a combination of thermoplastic polyurethane, a multi-walled carbon nanotube and an ionic liquid; according to the pressure sensor, material combination and structural design of the pressure sensor are optimized, so that global accurate detection of static and dynamic forces is realized. By means of the synergistic effect of an ion capacitance mechanism and a piezoelectric effect, the stability of static force detection is guaranteed, and rapid response of dynamic force is achieved.

Description

Technical Field

[0001] This invention belongs to the field of sensors and relates to a pressure sensor, and more particularly to a dual-mode flexible pressure sensor based on ion-capacitance-piezoelectric coupling. Background Technology

[0002] Pressure sensors, as core components for sensing external mechanical signals, have wide applications in fields such as industrial automation, medical monitoring, wearable electronics, and robotic tactile sensing.

[0003] Flexible pressure sensors, with their excellent flexibility and sensitivity, have shown broad application prospects in fields such as smart wearables and robotic haptics. However, most existing sensors are based on a single sensing mechanism (such as piezoresistive, piezoelectric, or capacitive), which makes it difficult to simultaneously meet the accurate detection requirements of dynamically changing forces and static constant forces, resulting in problems such as limited response range, signal lag, or insufficient stability.

[0004] In recent years, composite mechanism sensors have become a research hotspot, but they still face challenges in terms of material compatibility, structural design, and performance synergy. For example, although piezoelectric materials respond quickly, they are difficult to maintain static signal output; capacitive sensors have excellent static performance but slow dynamic response.

[0005] Therefore, it is of great significance to develop a dual-mode flexible pressure sensor that combines high sensitivity, fast response, and wide-range detection capability. Summary of the Invention

[0006] This application provides a pressure sensor to solve or alleviate one or more of the technical problems mentioned above.

[0007] The first aspect of this application provides a pressure sensor, which includes a dielectric layer, a conductive layer and an electrode layer sequentially disposed on both sides of the dielectric layer.

[0008] Preferably, the dielectric layer is a piezoelectric thin film layer that has undergone polarization treatment.

[0009] Preferably, the piezoelectric thin film layer is made of polyvinylidene fluoride or a copolymer of polyvinylidene fluoride and trifluoroethylene.

[0010] Preferably, when the piezoelectric thin film layer is made of polyvinylidene fluoride, the electric field strength of the polarization treatment is 90-110 kV / cm, and the time is 20-40 min.

[0011] Preferably, when the piezoelectric thin film layer is made of vinylidene fluoride trifluoroethylene copolymer, the electric field strength of the polarization treatment is 70-90 kV / cm, and the time is 10-30 min.

[0012] Preferably, the method for preparing the conductive layer includes: printing conductive ink, heating, and forming a conductive layer.

[0013] Preferably, the printing method is screen printing or ink printing.

[0014] Preferably, the heating temperature is 50-70℃ and the heating time is 20-40 minutes.

[0015] Preferably, the method for preparing the conductive ink includes: adding multi-walled carbon nanotubes to a polymer solution under stirring conditions, maintaining the mixture for 0.5-2 hours, then adding an ionic liquid, maintaining the mixture for 15-45 minutes, to obtain the conductive ink.

[0016] Preferably, the stirring rate is 1000-1200 r / min.

[0017] Preferably, based on an addition amount of 2.5g of thermoplastic polyurethane to the polymer solution, the addition amount of multi-walled carbon nanotubes is 0.2-0.8g, and the addition amount of ionic liquid is 2-4mL.

[0018] Preferably, the polymer comprises thermoplastic polyurethane or polydimethylsiloxane.

[0019] Preferably, the ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imine.

[0020] Preferably, the method for preparing the polymer solution includes: dissolving the polymer in N,N-dimethylformamide at 90-110°C, and then cooling it to 10-40°C to obtain the polymer solution.

[0021] Preferably, based on an addition amount of 2.5g of polymer, the addition amount of N,N-dimethylformamide is 7-9mL.

[0022] Preferably, the electrode layer is a flexible printed electrode.

[0023] Preferably, the method for preparing the electrode layer includes: printing electrode ink on a flexible substrate and curing it to obtain the electrode layer.

[0024] Preferably, the printing method is screen printing or ink printing.

[0025] Preferably, the flexible substrate is a PI substrate.

[0026] Preferably, the curing temperature is 60-80℃.

[0027] Preferably, with the dielectric layer having a thickness of 20-50 μm, the conductive layer has a thickness of 50-100 μm, and the electrode layer has a thickness of 20-30 μm.

[0028] A second aspect of this application is to provide a method for manufacturing a pressure sensor as described in one of the objectives, the method comprising:

[0029] A conductive layer and an electrode layer are sequentially disposed on both sides of the dielectric layer, and then hot-pressed at 50-60℃ for 60-120s to obtain a pressure sensor.

[0030] Preferably, the preparation method further includes sealing the edges and curing with an edge-sealing material.

[0031] Preferably, the edge sealing material includes epoxy resin and / or UV-curable adhesive.

[0032] Preferably, when the curing is a vacuum drying process, the vacuum degree of the vacuum drying process is -0.05 to -0.2 MPa, the temperature is 50-60℃, and the time is 0.5-1.5 h.

[0033] A third aspect of this application is to provide an application of the pressure sensor as described in one of the objectives in the fields of robot tactile perception, health monitoring, or human-computer interaction.

[0034] Technical features and beneficial effects of the present invention:

[0035] In this application, the pressure sensor achieves efficient dynamic and static detection by constructing an "ion-capacitance-piezoelectric" coupling structure, combining the enhanced ion conduction path of multi-walled carbon nanotubes and ionic liquids, and the piezoelectric properties of the polarized piezoelectric thin film.

[0036] In this application, by leveraging the synergistic effect of ionic capacitance mechanism and piezoelectric effect, both the stability of static force detection and the rapid response of dynamic force are ensured. Attached Figure Description

[0037] Figure 1 The structure of the pressure sensor in the specific implementation embodiment;

[0038] Explanation of reference numerals in the attached figures: 1 is the first electrode layer, 2 is the first conductive layer, 3 is the dielectric layer, 4 is the second conductive layer, and 5 is the second electrode layer;

[0039] Figure 2 The static pressure response test diagram of the pressure sensor obtained in Example 1 is shown.

[0040] Figure 3 The image shows the dynamic impact response test diagram of the pressure sensor obtained in Example 1. Detailed Implementation

[0041] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0042] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they 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 application according to the specific circumstances.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0046] This application provides a technical solution for a pressure sensor, as detailed below.

[0047] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0048] This application provides a pressure sensor, which includes a dielectric layer, a conductive layer and an electrode layer sequentially disposed on both sides of the dielectric layer.

[0049] In this application, the sensor is a dual-mode flexible pressure sensor based on ion-capacitance-piezoelectric coupling. Through material combination and structural design, it achieves accurate detection of static and dynamic forces across the entire range.

[0050] In this application, the sensor utilizes the synergistic effect of ion capacitance mechanism and piezoelectric effect to ensure the stability of static force detection and achieve rapid response to dynamic force.

[0051] In this application, the electrode layer serves to collect charge and conduct signals, enabling the electrical signals generated by ionic capacitance or piezoelectric effect to be exported to an external circuit. Under pressure, the distance between the conductive layer and the electrode layer decreases, changing the capacitance value of the double layer and outputting a stable static signal. Furthermore, under rapid pressure changes, it can assist charge migration and reduce signal delay. Under rapid pressure changes, the dielectric layer can generate instantaneous charge, shorten the response time, prevent short circuits between electrodes, and transmit pressure to the ionic conductive film.

[0052] like Figure 1 As shown, the pressure sensor includes a first electrode layer 1, a first conductive layer 2, a dielectric layer 3, a second conductive layer 4, and a second electrode layer 5 stacked sequentially from top to bottom; the whole stack forms a "sandwich" structure; wherein, the conductive layer is in contact with the electrode layer, and the dielectric layer is located between the first conductive layer and the second conductive layer, and the coupling effect of ionic capacitance and piezoelectric effect is achieved through this structural design.

[0053] In a specific embodiment, the dielectric layer is a piezoelectric thin film layer that has undergone polarization treatment.

[0054] In a specific embodiment, the piezoelectric thin film layer is made of polyvinylidene fluoride or a copolymer of polyvinylidene fluoride and trifluoroethylene.

[0055] In this application, the dielectric layer is a piezoelectric thin film layer that has undergone polarization treatment. By polarizing the piezoelectric thin film layer, a fast response for dynamic force detection can be guaranteed.

[0056] In this application, the material of the piezoelectric thin film layer is preferably polyvinylidene fluoride or polyvinylidene fluoride trifluoroethylene copolymer. These two polymers have high piezoelectric constants and can achieve highly sensitive dynamic sensing.

[0057] In a specific embodiment, when the piezoelectric thin film layer is made of polyvinylidene fluoride, the electric field strength of the polarization treatment is 90-110 kV / cm (e.g., 90 kV / cm, 95 kV / cm, 100 kV / cm, 105 kV / cm, 110 kV / cm, etc.), and the time is 20-40 min (e.g., 20 min, 25 min, 30 min, 35 min, 40 min, etc.).

[0058] In this application, when the piezoelectric thin film layer is polyvinylidene fluoride, the electric field strength and time of the polarization treatment are within the range defined in this application, resulting in good piezoelectric output and thus ensuring a fast response of dynamic force detection; when the electric field strength and time of the polarization treatment are not within the range defined in this application, the response time of dynamic force detection will be affected.

[0059] In a specific embodiment, when the piezoelectric thin film layer is made of vinylidene fluoride trifluoroethylene copolymer, the electric field strength of the polarization treatment is 70-90 kV / cm (e.g., 70 kV / cm, 75 kV / cm, 80 kV / cm, 85 kV / cm, 90 kV / cm, etc.), and the time is 10-30 min (e.g., 10 min, 15 min, 20 min, 25 min, 30 min, etc.).

[0060] In this application, when the piezoelectric thin film layer is a vinylidene fluoride trifluoroethylene copolymer, the electric field strength and time of the polarization treatment are within the range defined in this application, resulting in good piezoelectric output and thus ensuring a fast response of dynamic force detection; when the electric field strength and time of the polarization treatment are not within the range defined in this application, the response time of dynamic force detection will be affected.

[0061] In a specific embodiment, the method for preparing the conductive layer includes: printing conductive ink, heating, and forming a conductive layer.

[0062] In a specific embodiment, the heating temperature is 50-70℃ (e.g., 50℃, 55℃, 60℃, 65℃, 70℃, etc.), and the heating time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0063] In this application, the solvent in the conductive ink is removed by heat treatment to form a film structure. When the heating temperature is 50-70℃ and the heating time is 20-40 minutes, the solvent in the conductive ink can be removed quickly, and the resulting film structure has high flatness.

[0064] In a specific embodiment, the method for preparing the conductive ink includes: adding multi-walled carbon nanotubes to a polymer solution under stirring conditions and maintaining the solution for 0.5-2 hours (e.g., 0.5 hours, 1 hour, 1.5 hours, 2 hours, etc.), then adding an ionic liquid and maintaining the solution for 15-45 minutes (e.g., 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, etc.) to obtain the conductive ink.

[0065] In this application, multi-walled carbon nanotubes (MWCNTs) and ionic liquids are added to conductive inks. The core purpose is to construct efficient ion conduction pathways to support the ion capacitance mechanism of sensors. MWCNTs possess high specific surface area and conductivity, enabling them to form a three-dimensional network structure in thermoplastic polyurethane or polydimethylsiloxane, providing a rapid migration path for ion conduction and enhancing the mechanical stability and dispersibility of the conductive ink. Ionic liquids provide mobile cations and anions. Under pressure, these ions form an electrical double layer on the electrode-conductive layer, improving capacitance for detecting static forces and also enhancing the mechanical stability and dispersibility of the conductive ink. When MWCNTs and ionic liquids work together, MWCNTs provide a framework to support ion migration, while the ionic liquid fills the gaps between the nanotubes, forming an efficient conduction network. Together, they solve problems such as uniformity and response hysteresis in conductive inks.

[0066] In a specific embodiment, the stirring rate is 1000-1200 r / min (e.g., 1000 r / min, 1050 r / min, 1100 r / min, 1150 r / min, 1200 r / min, etc.).

[0067] In a specific embodiment, with the amount of thermoplastic polyurethane added to the polymer solution being 2.5g, the amount of multi-walled carbon nanotubes added is 0.2-0.8g (e.g., 0.2g, 0.4g, 0.5g, 0.6g, 0.8g, etc.), and the amount of ionic liquid added is 2-4mL (e.g., 2mL, 3mL, 4mL, etc.).

[0068] In a specific embodiment, the polymer includes thermoplastic polyurethane or polydimethylsiloxane.

[0069] In a specific embodiment, the ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide.

[0070] In a specific embodiment, the preparation method of the polymer solution includes: dissolving the polymer in N,N-dimethylformamide at 90-110°C (e.g., 90°C, 95°C, 100°C, 105°C, 110°C, etc.), and then cooling to 10-40°C (e.g., 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc.) to obtain the polymer solution.

[0071] In this application, by dissolving the polymer in N,N-dimethylformamide at high temperature and then cooling it to 10-40°C, the polymer molecular chains can be fully extended in N,N-dimethylformamide, accelerating the dissolution process. On the other hand, the cooling treatment can provide a low-temperature dispersion environment for multi-walled carbon nanotubes and ionic liquids, preventing agglomeration and ensuring conductivity, ultimately facilitating the ion mobility of the conductive layer and the response performance of the sensor.

[0072] In a specific embodiment, based on an addition amount of 2.5g of polymer, the addition amount of N,N-dimethylformamide is 7-9mL (e.g., 7mL, 8mL, 9mL, etc.);

[0073] In a specific embodiment, the electrode layer is a flexible printed electrode.

[0074] In this application, the electrode layer is a flexible printed electrode or a silver nanoprinted electrode, making the resulting pressure sensor a flexible structure that can adapt to the fitting requirements of complex curved surfaces; when the electrode layer is a silver nanoprinted flexible electrode, the interface contact resistance can be reduced while maintaining flexibility.

[0075] In a specific embodiment, the method for preparing the electrode layer includes: using screen printing technology or inkjet printing technology to print electrode ink onto a flexible substrate, and heating and curing it at 60-80℃ (e.g., 60℃, 65℃, 70℃, 75℃, 80℃, etc.) to form an electrode layer.

[0076] In this application, a PI substrate is preferred as the flexible substrate, thereby ensuring the mechanical strength and flexibility of the pressure sensor.

[0077] In a specific embodiment, with the thickness of the dielectric layer being 20-50 μm (e.g., 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.), the thickness of the conductive layer is 50-100 μm (e.g., 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc.), and the thickness of the electrode layer is 20-30 μm (e.g., 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, etc.).

[0078] In a specific embodiment, this application provides a method for fabricating a pressure sensor, comprising: sequentially depositing a conductive layer and an electrode layer on both sides of a dielectric layer, and hot-pressing at 50-60℃ (e.g., 50℃, 52℃, 55℃, 58℃, 60℃, etc.) for 60-120s (e.g., 60s, 70s, 80s, 90s, 100s, 110s, 120s, etc.) to obtain a pressure sensor.

[0079] In a specific embodiment, the preparation method further includes sealing the edges and curing with an edge-sealing material.

[0080] In a specific embodiment, the sealing material includes epoxy resin and / or UV-curable adhesive.

[0081] In a specific embodiment, when the curing is a vacuum drying process, the vacuum degree of the vacuum drying process is -0.05 to -0.2 MPa (e.g., -0.05 MPa, -0.08 MPa, -0.1 MPa, -0.12 MPa, -0.15 MPa, -0.18 MPa, -0.2 MPa, etc.), the temperature is 50-60℃ (e.g., 50℃, 52℃, 55℃, 58℃, 60℃, etc.), and the time is 0.5-1.5h (e.g., 0.5h, 0.8h, 1h, 1.2h, 1.5h, etc.).

[0082] In specific implementations, pressure sensors are used in the fields of robot tactile perception, health monitoring, or human-computer interaction.

[0083] The following section presents performance tests on the pressure sensor or manufacturing method provided in the embodiments of this application, as well as related comparative examples.

[0084]

Example 1

[0085] This embodiment provides a pressure sensor, which includes, from top to bottom, a first electrode layer, a first conductive layer, a dielectric layer, a second conductive layer, and a second electrode layer stacked sequentially.

[0086] This embodiment also provides a method for manufacturing a pressure sensor, including:

[0087] (1) Fabrication of the electrode layers (including the first electrode layer and the second electrode layer):

[0088] Electrode ink (purchased from Shanghai Ouyi Organic Optoelectronic Materials Co., Ltd.) was printed onto a flexible PI substrate using screen printing technology and cured at 70°C to form an electrode layer.

[0089] (2) Fabrication of the conductive layer (including the first conductive layer and the second conductive layer):

[0090] 2.5g of thermoplastic polyurethane (purchased from Ruixiang Polymer Materials Business Department, Zhangmutou City, Dongguan) was dissolved in 8mL of N,N-dimethylformamide and magnetically stirred at 100℃ until completely dissolved. After cooling to room temperature, 0.5g of MWCNTs was added and stirred for 1h. Then, 3mL of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was slowly added dropwise and stirred for 30min to obtain a uniform ion-conductive ink. The ink was printed on the designated area using screen printing technology, and the solvent was removed by heating at 60℃ to form a conductive layer.

[0091] (3) Fabrication of the dielectric layer:

[0092] A PVDF piezoelectric film with a thickness of 50 μm (purchased from Polyk Technologies LLC) was polarized for 30 min under an electric field of 100 kV / cm to obtain a dielectric layer.

[0093] (4) Sensor assembly:

[0094] The first electrode layer, the first conductive layer, the dielectric layer, the second conductive layer, and the second electrode layer are stacked sequentially to form a "sandwich" structure. The edges are sealed with flexible epoxy resin. The structure is cured at 55°C for 1 hour under a vacuum of -0.2 MPa, and then placed in a hot press and hot-pressed at 55°C for 90 seconds under a pressure of 1.0 MPa to form a sensor.

[0095] The sensor prepared in Example 1 was subjected to a static pressure response test, such as... Figure 2 As shown, this pressure sensor achieves stable detection of static pressure within a pressure range of 10-100 kPa.

[0096] The sensor prepared in Example 1 was subjected to dynamic impact response testing, such as... Figure 3 As shown, the pressure sensor has a response time of 19ms based on the piezoelectric effect, which meets the requirements for high-speed dynamic force detection.

[0097]

Example 2

[0098] This embodiment provides a pressure sensor, which includes, from top to bottom, a first electrode layer, a first conductive layer, a dielectric layer, a second conductive layer, and a second electrode layer stacked sequentially.

[0099] This embodiment also provides a method for manufacturing a pressure sensor, including:

[0100] (1) Fabrication of the electrode layers (including the first electrode layer and the second electrode layer):

[0101] Electrode ink is printed onto a flexible PI substrate using screen printing technology and cured at 60°C to form an electrode layer.

[0102] (2) Fabrication of the conductive layer (including the first conductive layer and the second conductive layer):

[0103] 2.5 g of thermoplastic polyurethane was dissolved in 7 mL of N,N-dimethylformamide and magnetically stirred at 90 °C until completely dissolved. After cooling to room temperature, 0.2 g of MWCNTs was added and stirred for 0.5 h. Subsequently, 4 mL of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was slowly added dropwise and stirred for 15 min to obtain a uniform ion-conductive ink. The ink was printed on a designated area using screen printing technology, and the solvent was removed by heating at 50 °C to form a conductive layer.

[0104] (3) Fabrication of the dielectric layer:

[0105] A PVDF piezoelectric film with a thickness of 30 μm was polarized under an electric field of 90 kV / cm for 40 min to obtain a dielectric layer.

[0106] (4) Sensor assembly:

[0107] The first electrode layer, the first conductive layer, the dielectric layer, the second conductive layer, and the second electrode layer are stacked sequentially to form a "sandwich" structure. The edges are sealed with flexible epoxy resin. The structure is cured at 50°C for 1.5 hours under a vacuum of -0.1 MPa, and then placed in a hot press and hot-pressed at 50°C for 120 seconds to form a sensor.

[0108] The sensor prepared in Example 2 was subjected to the same static pressure response test as in Example 1. It was found that the pressure sensor also achieved stable detection of static pressure within the pressure range of 10-100 kPa.

[0109] The sensor prepared in Example 2 was subjected to the same dynamic impact response test as in Example 1. The pressure sensor, based on the piezoelectric effect, has a response time of 19ms, which meets the requirements for high-speed dynamic force detection.

[0110]

Example 3

[0111] This embodiment provides a pressure sensor, which includes, from top to bottom, a first electrode layer, a first conductive layer, a dielectric layer, a second conductive layer, and a second electrode layer stacked sequentially.

[0112] This embodiment also provides a method for manufacturing a pressure sensor, including:

[0113] (1) Fabrication of the electrode layers (including the first electrode layer and the second electrode layer):

[0114] Electrode ink is printed onto a flexible PI substrate using screen printing technology and cured at 80°C to form an electrode layer.

[0115] (2) Fabrication of the conductive layer (including the first conductive layer and the second conductive layer):

[0116] 2.5 g of thermoplastic polyurethane was dissolved in 9 mL of N,N-dimethylformamide and magnetically stirred at 110 °C until completely dissolved. After cooling to room temperature, 0.8 g of MWCNTs was added and stirred for 2 h. Then, 2 mL of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was slowly added dropwise and stirred for 45 min to obtain a uniform ion-conductive ink. The ink was printed on a designated area using screen printing technology, and the solvent was removed by heating at 70 °C to form a conductive layer.

[0117] (3) Fabrication of the dielectric layer:

[0118] A PVDF piezoelectric film with a thickness of 30 μm was polarized under an electric field of 110 kV / cm for 20 min to obtain a dielectric layer.

[0119] (4) Sensor assembly:

[0120] The first electrode layer, the first conductive layer, the dielectric layer, the second conductive layer, and the second electrode layer are stacked sequentially to form a "sandwich" structure. The edges are sealed with flexible epoxy resin. The structure is cured at 60°C for 0.5 hours under a vacuum of -0.05 MPa, and then placed in a hot press and hot-pressed at 60°C for 60 seconds to form a sensor.

[0121] The sensor prepared in Example 3 was subjected to the same static pressure response test as in Example 1. It was found that the pressure sensor also achieved stable detection of static pressure within the pressure range of 10-100 kPa.

[0122] The sensor prepared in Example 3 was subjected to the same dynamic impact response test as in Example 1. The pressure sensor, based on the piezoelectric effect, has a response time of 19ms, which meets the requirements for high-speed dynamic force detection.

[0123]

Example 4

[0124] This embodiment provides a pressure sensor, which includes, from top to bottom, a first electrode layer, a first conductive layer, a dielectric layer, a second conductive layer, and a second electrode layer stacked sequentially.

[0125] This embodiment also provides a method for manufacturing a pressure sensor, including:

[0126] (1) Fabrication of the electrode layers (including the first electrode layer and the second electrode layer):

[0127] Electrode ink is inkjet printed onto a flexible PI substrate using screen printing technology, and then cured at 70°C to form an electrode layer.

[0128] (2) Fabrication of the conductive layer (including the first conductive layer and the second conductive layer):

[0129] 2.5g of polydimethylsiloxane (model DC184, purchased from Dow Corning) and 0.25g of curing agent (specific name or model DC184 curing agent) were dissolved in 8mL of N,N-dimethylformamide. The solution was magnetically stirred at 100℃ until completely dissolved. After cooling to room temperature, 0.5g of MWCNTs were added and stirred for 2h. Then, 3mL of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt was slowly added dropwise, and stirring was continued for 45min to obtain a uniform ion-conductive ink. The ink was printed on the designated area using inkjet printing technology, and the solvent was removed by heating at 60℃ to form a conductive layer.

[0130] (3) Fabrication of the dielectric layer:

[0131] A 50 μm thick vinylidene fluoride trifluoroethylene copolymer piezoelectric film (purchased from Polyk Technologies LLC.) was polarized for 20 min under an electric field of 80 kV / cm to obtain a dielectric layer.

[0132] (4) Sensor assembly:

[0133] The first electrode layer, the first conductive layer, the dielectric layer, the second conductive layer, and the second electrode layer are stacked sequentially to form a "sandwich" structure. The edges are sealed with flexible epoxy resin. The structure is cured at 55°C for 1 hour under a vacuum of -0.1 MPa, and then placed in a hot press and hot-pressed at 55°C for 90 seconds to form a sensor.

[0134] The sensor prepared in Example 4 was subjected to the same static pressure response test as in Example 1. It was found that the pressure sensor achieved stable detection of static pressure within a pressure range of 10-100 kPa.

[0135] The sensor prepared in Example 4 was subjected to the same dynamic impact response test as in Example 1. The response time of this pressure sensor based on the piezoelectric effect is 21ms, which meets the requirements for high-speed dynamic force detection.

[0136] It should be noted that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., are used 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, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of the component itself. For example, if a device in the drawings is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0137] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0138] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0139] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A pressure sensor, characterized in that, The pressure sensor includes a dielectric layer, a conductive layer and an electrode layer sequentially disposed on both sides of the dielectric layer.

2. The pressure sensor according to claim 1, characterized in that, The dielectric layer is a piezoelectric thin film layer that has undergone polarization treatment; The piezoelectric thin film layer is made of polyvinylidene fluoride or a copolymer of polyvinylidene fluoride and trifluoroethylene. When the piezoelectric thin film layer is made of polyvinylidene fluoride, the electric field strength of the polarization treatment is 90-110 kV / cm, and the time is 20-40 min. When the piezoelectric thin film layer is made of vinylidene fluoride trifluoroethylene copolymer, the electric field strength of the polarization treatment is 70-90 kV / cm, and the time is 10-30 min.

3. The pressure sensor according to claim 1, characterized in that, The method for preparing the conductive layer includes: printing conductive ink, heating, and forming a conductive layer; The printing method is screen printing or inkjet printing; The heating temperature is 50-70℃, and the heating time is 20-40 minutes.

4. The pressure sensor according to claim 3, characterized in that, The method for preparing the conductive ink includes: Under stirring conditions, multi-walled carbon nanotubes are added to the polymer solution and kept for 0.5-2 hours. Then, ionic liquid is added and kept for 15-45 minutes to obtain conductive ink. The stirring rate is 1000-1200 r / min; Based on an addition amount of 2.5g of polymer in the polymer solution, the addition amount of the multi-walled carbon nanotubes is 0.2-0.8g, and the addition amount of the ionic liquid is 2-4mL; The polymer includes thermoplastic polyurethane or polydimethylsiloxane; The ionic liquid is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imine.

5. The pressure sensor according to claim 4, characterized in that, The method for preparing the polymer solution includes: dissolving the polymer in N,N-dimethylformamide at 90-110°C, and then cooling it to 10-40°C to obtain the polymer solution; Based on an addition amount of 2.5g of polymer, the addition amount of N,N-dimethylformamide is 7-9mL.

6. The pressure sensor according to claim 1, characterized in that, The electrode layer is a flexible printed electrode; The method for preparing the electrode layer includes: printing electrode ink on a flexible substrate and curing it to obtain the electrode layer; The printing method is screen printing or inkjet printing; The flexible substrate is a PI substrate; The curing temperature is 60-80℃.

7. The pressure sensor according to claim 1, characterized in that, With a dielectric layer thickness of 20-50 μm, the conductive layer thickness is 50-100 μm, and the electrode layer thickness is 20-30 μm.

8. The method for manufacturing a pressure sensor according to any one of claims 1-7, characterized in that, The preparation method includes: A conductive layer and an electrode layer are sequentially disposed on both sides of the dielectric layer, and then hot-pressed at 50-60℃ for 60-120s to obtain a pressure sensor.

9. The preparation method according to claim 8, characterized in that, The preparation method further includes sealing the edges with an edge-sealing material and curing it; The edge sealing material includes epoxy resin and / or UV-curable adhesive; When the curing is performed by vacuum drying, the vacuum degree of the vacuum drying process is -0.05 to -0.2 MPa, the temperature is 50-60℃, and the time is 0.5-1.5 h.

10. The application of the pressure sensor according to any one of claims 1-7 in the fields of robot tactile perception, health monitoring, or human-computer interaction.

Images