Wearable flexible pressure sensor and underwater physiological information monitoring system

Abstract

The utility model discloses a wearable flexible pressure sensor and an underwater physiological information monitoring system, and belongs to the technical field of underwater flexible electronic sensors. The flexible pressure sensor comprises an electrode layer, a spacing layer, a sensitive layer and a packaging layer, the electrode layer comprises a polyimide film, a flexible plate layer is arranged on one side of the polyimide film, and the flexible plate layer is connected with a wire; the spacing layer is of an annular structure and is made of nano glue; the sensitive layer comprises a TPU film, and a pyramid-shaped microstructure is formed on the TPU film; the electrode layer and the sensitive layer are bonded into a whole through the spacing layer, and the pyramid-shaped microstructure is in contact with the flexible plate layer; and the outer sides of the electrode layer, the wire and the sensitive layer are coated with a packaging layer. The wearable flexible pressure sensor can be directly worn on the wrist of an underwater worker to monitor pulse pressure in real time, is convenient to use, and can effectively improve the safety of the underwater worker.

Description

Technical Field

[0001] This utility model belongs to the field of underwater flexible electronic sensor technology, specifically relating to a wearable flexible pressure sensor and an underwater physiological information monitoring system. Background Technology

[0002] For personnel working in underwater environments, the complex and ever-changing conditions present significant challenges. Therefore, a highly sensitive, fast-responding, and reliable sensor is needed to acquire physiological data such as human pulse pressure signals. Traditional rigid sensors are bulky, have high production and maintenance costs, exhibit unstable performance in underwater environments, and some are even invasive, causing considerable inconvenience.

[0003] For example, Chinese utility model patent CN204147018U discloses an arterial pulsation detection device and a pressure sensor assembly. This device obtains the pressure signal of the measured part by squeezing a sealed lower elastic airbag around the lower pressure sensor to compress the location of the human artery, thereby obtaining the human pulse information. However, the lower elastic airbag and other structures used in this device are complex and large, making them unsuitable for underwater human pulse pressure detection. Utility Model Content

[0004] Based on the above-mentioned technical problems, this utility model proposes a wearable flexible pressure sensor and an underwater physiological information monitoring system.

[0005] The technical solution adopted by this utility model is:

[0006] A wearable flexible pressure sensor includes an electrode layer, a spacer layer, a sensitive layer, and an encapsulation layer. The electrode layer includes a polyimide film, and a flexible plate layer is disposed on one side of the polyimide film. The flexible plate layer is connected to a wire.

[0007] The spacer layer has a ring structure and is made using nano-adhesive processing.

[0008] The sensitive layer includes a TPU film, on which a pyramid-shaped microstructure is formed;

[0009] The electrode layer and the sensitive layer are bonded together by a spacer layer, which allows the pyramid-shaped microstructure to come into contact with the flexible plate layer;

[0010] An encapsulation layer covers the outside of the electrode layer, wires, and sensitive layer.

[0011] Preferably, the flexible board layer is a flexible printed circuit board obtained by laser etching; the flexible printed circuit board adopts interdigitated microelectrodes, the interdigitated microelectrodes adopt several annular interdigitated structures with different diameters, and all annular interdigitated structures are arranged concentrically; the linewidth of the interdigitated microelectrodes is 0.2-0.3mm, and the thickness of the interdigitated microelectrodes is 0.5-0.6mm.

[0012] Preferably, the spacer layer is an annular circle with a thickness of 200-300 μm and a ring width of 5-6 mm.

[0013] Preferably, the pyramid-shaped microstructure is formed by etching on a TPU film, and the pyramid-shaped microstructure includes several pyramid-shaped units of different sizes that are randomly and irregularly distributed.

[0014] Preferably, the encapsulation layer is made of PDMS material, and an uneven groove microstructure is formed on the surface of the encapsulation layer; the width of the protrusions of the groove microstructure is 2-3 μm, and the interval between adjacent protrusions in the groove microstructure is 2-3 μm.

[0015] This utility model also provides an underwater physiological information monitoring system, which uses the wearable flexible pressure sensor described above. The wearable flexible pressure sensor can be worn on the wrist of an underwater person as a data acquisition module.

[0016] The underwater physiological information monitoring system also includes a central control module and an alarm module. The data acquisition module is connected to the central control module, and the central control module is connected to the alarm module.

[0017] The data acquisition module uses underwater physiological information for real-time monitoring and transmission; the central control module is used for data processing and determining whether an alarm signal should be output. If the detected data exceeds the safety threshold, an alarm signal is issued; the alarm module is used to receive alarm signals from the central control module in real time and issue a warning response.

[0018] The beneficial technical effects of this utility model are:

[0019] 1. This utility model of wearable flexible pressure sensor can be directly worn on the wrist of underwater workers to monitor pulse pressure in real time. It has high monitoring stability and accuracy, good sealing and waterproof effect, is convenient to wear and use, and is comfortable, which can effectively improve the safety of underwater workers. Moreover, it has low manufacturing cost and is easy to promote and use in the market.

[0020] 2. This utility model uses a flexible printed circuit board (FPCB) as the electrode layer and nano double-sided adhesive as the spacer layer, which ensures flexibility and has a good waterproof sealing effect. It has low production cost, can be mass-produced, and has strong scalability.

[0021] 3. This invention prepares a sensitive layer with random and irregular pyramid-shaped microstructure by etching, and uses the sensitive layer in combination with the interdigitated microelectrodes of the FPCB to greatly enhance the sensitivity of the sensor.

[0022] 4. This utility model uses PDMS as the encapsulation material, which has a good sealing and waterproof effect, and can be directly injection molded into a flexible wristband structure, making it easy to process; furthermore, it forms a concave-convex microstructure on the encapsulation surface, which effectively prevents the adhesion of marine microorganisms and increases the stability of the sensor.

[0023] 5. This utility model also provides an underwater physiological information monitoring system, in which a wearable flexible pressure sensor can serve as the data acquisition module. The flexible wristband design of the sensor improves wearability, and the sensor designed in this utility model can also improve the efficiency and accuracy of underwater monitoring, providing good real-time performance and contributing to the stability and reliability of the underwater physiological information monitoring system. This utility model's underwater physiological information monitoring system also includes a central control module and an alarm module, which can issue an early warning response when the sensor's monitoring data exceeds a safety threshold, effectively improving the safety of underwater personnel. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 This is a schematic diagram illustrating the structural principle of the electrode layer in the wearable flexible pressure sensor of this utility model;

[0026] Figure 2 This is a schematic diagram illustrating the structural principle of the spacer layer in the wearable flexible pressure sensor of this utility model.

[0027] Figure 3 This is a schematic diagram illustrating the structural principle of the sensitive layer in the wearable flexible pressure sensor of this utility model;

[0028] Figure 4 This is a schematic diagram of the packaging mold used in the fabrication of the wearable flexible pressure sensor of this utility model;

[0029] Figure 5 This is a structural block diagram of the wearable flexible pressure sensor of this utility model;

[0030] Figure 6 This is a structural block diagram of the underwater physiological information monitoring system of this utility model.

[0031] In the diagram: 1-Electrode layer, 2-Spacer layer, 3-Sensitive layer, 4-Encapsulation layer, 5-Wire, 6-Ring interdigitated structure, 7-Alarm module, 8-Template, 9-Central control module;

[0032] 301-TPU film, 302-Pyramid-shaped microstructure; 701-LED alarm device, 702-Buzzer alarm device; 801-Circular casting groove, 802-Elongated casting groove. Detailed Implementation

[0033] Example 1

[0034] like Figure 1-3 , Figure 5 As shown, a wearable flexible pressure sensor includes an electrode layer 1, a spacer layer 2, a sensing layer 3, and an encapsulation layer 4. Figure 1 As shown, the electrode layer 1 includes a polyimide film (PI film), and a flexible board layer is disposed on one side of the polyimide film. The flexible board layer is connected to the wire 5. The flexible board layer is a flexible printed circuit board (FPCB) obtained by laser etching, and undergoes heat resistance and electrical characteristic tests to ensure the stability and reliability of the electrode layer performance. The flexible printed circuit board and the polyimide film are bonded together by a hot-pressing process, that is, the polyimide film is used as a flexible substrate, and the flexible printed circuit board is bonded to it by a hot-pressing process. The flexible printed circuit board uses interdigitated microelectrodes, which employ several annular interdigitated structures 6 with different diameters. Notches are provided on the annular interdigitated structures 6, and the notches on adjacent annular interdigitated structures face different directions. All annular interdigitated structures are arranged concentrically, such as... Figure 1 As shown. The line width of the ring-shaped interdigitated structure is 0.2-0.3 mm, and the thickness of the ring-shaped interdigitated structure is 0.5-0.6 mm.

[0035] Compared to traditional rigid circuit boards, the flexible printed circuit board used in this invention is thin, light, and foldable, allowing for a large degree of bending and attachment to various surfaces. Furthermore, the interdigitated microelectrodes on the flexible printed circuit board employ multiple ring-shaped interdigitated structures, ensuring that even minute resistance changes between the interdigitated microelectrode structures can be sensitively detected, thus significantly improving the sensitivity of the interdigitated electrode sensor. Moreover, while the traditional method for obtaining the electrode layer is screen printing, this application innovatively uses FPCB instead, ensuring design flexibility for the electrode layer and improving the stability and measurement accuracy of the sensor, making mass production possible.

[0036] like Figure 2As shown, the spacer layer 2 has a ring-shaped structure and is made using nano-adhesive. Specifically, the spacer layer 2 is a ring-shaped circle with a thickness of 200-300 μm and a ring width of 5-6 mm. The diameter of the spacer layer 2 is equal to or slightly smaller than the diameter of the flexible plate layer. The spacer layer 2 can be processed using laser cutting technology and serves as the bonding interface between the electrode layer 1 and the sensitive layer 3. Compared to the preparation of traditional spacers, the nano-double-sided adhesive spacer layer has a simple manufacturing process, high adhesion, is easy to use, can be cut to any size, and has the advantages of being waterproof and corrosion-resistant, greatly improving the performance stability of the sensor.

[0037] like Figure 3 As shown, the sensitive layer 3 includes a TPU film 301, on which a pyramid-shaped microstructure 302 is formed. The pyramid-shaped microstructure 302 is formed by etching on the TPU film and comprises several pyramidal units of varying sizes, randomly and irregularly distributed. The microstructure of the sensitive layer is a pyramid shape of varying sizes, which has a low initial contact area with the electrode layer, resulting in a low initial resistance for the sensor. As the applied pressure increases, the initial contact area increases; furthermore, it creates new contact areas with the electrode layer, exhibiting a near-linear change in contact area, resulting in good linearity and improving the overall sensitivity of the sensor.

[0038] During assembly, electrode layer 1 and sensitive layer 3 are bonded together by spacer layer 2 to form a closed structure, allowing the pyramid-shaped microstructure 302 to contact the flexible plate layer. Spacer layer 2 is a ring-shaped structure with a completely hollow center, ensuring tight adhesion between electrode layer 1 and sensitive layer 3 while allowing for sufficient contact. This effectively suppresses multi-field interference in complex underwater environments and enhances the stability of the sensor. An encapsulation layer 4 covers the outer sides of electrode layer 1, wire 5, and sensitive layer 3. The encapsulation layer 4 is made of PDMS material, and its surface has an uneven groove microstructure. The width of the groove microstructure protrusions is 2-3 μm, and the spacing between adjacent protrusions is 2-3 μm.

[0039] This invention uses polydimethylsiloxane (PDMS) as the encapsulation material and forms microstructures on the surface of the encapsulation material to improve the roughness and hydrophobicity of the encapsulation surface. This not only provides a good sealing effect but also prevents marine organisms from attaching, avoids interference with the sensor, and ensures its stable operation.

[0040] The flexible pressure sensor obtained in this embodiment has the advantages of high stability, high sensitivity and fast response time.

[0041] The aforementioned wearable flexible pressure sensor can be manufactured using the following steps:

[0042] (1) Prepare the electrode layer;

[0043] A flexible printed circuit board (PCB) is prepared using laser etching. The PCB is then bonded to one side of a polyimide film using a thermosetting process to obtain electrode layer 1. Electrode layer 1 is disk-shaped. Conductors 5 are led out from both ends of electrode layer 1 and connected to the flexible PCB.

[0044] (2) Preparation of the sensitive layer;

[0045] A TPU film was selected as the substrate, and a silicon wafer etching process was used to etch pyramid-shaped microstructures of varying sizes and random, irregular distribution onto the TPU film to obtain the sensitive layer 3. The sensitive layer 3 is also disk-shaped, and its size is adapted to that of the electrode layer 1.

[0046] Specifically, it includes the following steps:

[0047] (21) Prepare boron nitride ion solution;

[0048] Boron nitride ionic liquid was prepared by selecting 2g TPU particles, 5ml dimethylformamide (DMF) solution, 1ml ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt) and 2g boron nitride powder as raw materials.

[0049] (22) Pre-process the silicon wafer template;

[0050] First, use 5ml of HF solution to remove the oxide layer on the silicon wafer to avoid doping with unknown impurities. Then, immerse the silicon wafer in a mixed solution of 10ml of KOH and isopropanol (the volume ratio of KOH to isopropanol is 2:1). After 1 hour, remove it and let it air dry naturally to increase its hydrophilicity and roughness, thus obtaining the pretreated silicon wafer template.

[0051] (23) Prepare the sensitive layer;

[0052] The prepared boron nitride ion solution was spin-coated onto a pretreated silicon wafer template and then vacuum annealed. Subsequently, the cured ion membrane was peeled off from the silicon wafer template to obtain a sensitive layer with a pyramid-shaped microstructure.

[0053] (3) Prepare the spacer layer;

[0054] A ring-shaped spacer layer 2 is obtained by using nano-adhesive to process the material into a circular shape. The electrode layer 1 and the sensitive layer 3 are then bonded together through the spacer layer 2 to obtain a sealed composite layer.

[0055] (4) Encapsulation layer;

[0056] Using packaging molds, such as Figure 4As shown, the encapsulation mold includes a template 8, which is rectangular. A circular casting groove 801 is provided in the center of the rectangular template, and elongated casting grooves 802 are provided at both ends of the circular casting groove 801. The elongated casting grooves 802 are arranged along the length of the template 8, and the elongated casting grooves 802 are connected to the circular casting groove 801.

[0057] The packaging mold can be made by 3D printing. Then, a transparent protective varnish is sprayed on the inside of the packaging mold at a temperature of 20-25℃ and a distance of 30-45cm to ensure that the coating is evenly covered on the inner surface of the mold, which will facilitate subsequent demolding.

[0058] PDMS is used as the encapsulation material, and a PDMS solution is prepared. First, a portion of the PDMS solution is injected into the circular casting groove 801 and the elongated casting groove 802. After waiting for 2 hours, the bottom layer bubbles completely dissipate and the material is in a semi-cured state. The sealed composite layer obtained in step (3) is placed into the circular casting groove 801, and the wire 5 is placed into the elongated casting groove 802. The end of the wire 5 can be further connected to the storage module and / or communication module, etc. The storage module and / or communication module are integrated on the wristband to form a complete system. Then, the remaining PDMS solution is injected so that the sealed composite layer is completely wrapped. After waiting for 3 hours, a hot stamping machine is used to cure the material. The curing temperature is controlled at 100-120℃ and the curing time is 1-2 minutes to obtain a wearable flexible pressure sensor. The wearable flexible pressure sensor includes a corresponding solidified central circular sensing structure and wristband structures located at both ends of the central circular sensing structure. In other words, the circular casting groove 801, after curing, forms the central circular sensing structure; and the elongated casting grooves 802 at both ends, after curing, form the wristband structures at both ends. The wristband structure is 20cm long, 4cm wide, and 0.5cm thick. Because PDMS has strong tensile strength, the above structure design can meet the dimensions of the human wrist.

[0059] More specifically, the flexible PDMS encapsulation layer is obtained by mixing an elastomer and a curing agent in a 10:1 weight ratio, pouring the mixture into a 3D-printed encapsulation mold, and then curing it. The flexible encapsulation material, PDMS, possesses waterproof, non-stick, corrosion-resistant, and high-pressure-resistant properties, and its surface chemical properties are stable. Using this material as a surface encapsulation effectively prevents the adhesion of marine organisms such as starfish and shellfish, thus ensuring the overall stability of the sensor. The flexible PDMS encapsulation layer can be bent and attached at will, protecting the internal flexible circuitry from excessive deformation during stretching and bending. The overall structure of the cured flexible sensor is a wristwatch-style structure, designed to fit the human arm, effectively achieving wearable monitoring and increasing comfort.

[0060] Furthermore, an uneven groove microstructure is etched on the surface of the encapsulation layer 4 of the obtained wearable flexible pressure sensor.

[0061] Specifically, the encapsulation layer 4 uses laser etching technology to fabricate microstructures onto a silicon wafer, which are then transferred to the surface of the encapsulation material. This creates an uneven, trench-like structure on the surface, with microstructure protrusions 2 μm wide and spaced 2 μm apart. The introduction of these microstructures significantly reduces the effective contact area between marine microorganisms and the encapsulation surface, thereby weakening the interaction between the organisms and the encapsulation layer surface. Furthermore, the microstructures increase the surface roughness and hydrophobicity of the material, reducing the surface free energy. Compared to a smooth surface without microstructures, its hydrophobic and self-cleaning properties are significantly enhanced, effectively improving the stability of the sensor.

[0062] Example 2

[0063] like Figure 6 As shown, an underwater physiological information monitoring system employs a wearable flexible pressure sensor as described in the above embodiment. This wearable flexible pressure sensor can be worn on the wrist of an underwater personnel through a solidified wristband structure, serving as a data acquisition module, or data acquisition end. This data acquisition end is stable, reliable, and responsive, capable of real-time monitoring of the diver's wrist pulse pressure data.

[0064] The underwater physiological information monitoring system also includes a central control module 9 and an alarm module 7. The data acquisition module is connected to the central control module 9, and the central control module 9 is connected to the alarm module 7.

[0065] The data acquisition module is used to monitor and transmit the diver's physiological information (pulse pressure value in the underwater environment) in real time. The central control module 9 is used to receive and process data, and determine whether an alarm signal should be output. If the detected data exceeds the safety threshold, an alarm signal is issued. The alarm module 7 is used to receive alarm signals from the central control module 9 in real time and issue a warning response.

[0066] Furthermore, the alarm module 7 includes an LED alarm device 701 and a buzzer alarm device 702. The LED alarm device 701 and the buzzer alarm device 702 receive the alarm signal transmitted by the central control module 9 and issue a warning signal. The warning signal is indicated by flashing lights and a buzzer.

[0067] This invention can monitor the pulse pressure information of underwater workers in real time, improve the underwater sensor monitoring network, and enhance the safety of underwater workers.

[0068] For any parts not mentioned above, existing technologies can be adopted or referenced.

[0069] Of course, the above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model and should be protected by the present utility model.

Claims

1. A wearable flexible pressure sensor, characterized by: It comprises an electrode layer, a spacer layer, a sensitive layer and an encapsulation layer, the electrode layer comprises a polyimide film, a flexible plate layer is arranged on one side of the polyimide film, and the flexible plate layer is connected with a wire; The spacer layer is in a ring structure and is made of nano glue; The sensitive layer comprises a TPU film, and a pyramid-shaped microstructure is formed on the TPU film; The electrode layer and the sensitive layer are bonded into one through the spacer layer, and the pyramid-shaped microstructure is in contact with the flexible plate layer; An encapsulation layer is arranged on the outer side of the electrode layer, the wire and the sensitive layer.

2. The wearable flexible pressure sensor of claim 1, wherein: The flexible plate layer is a flexible printed circuit board obtained by laser etching; the flexible printed circuit board adopts interdigital microelectrodes, the interdigital microelectrodes adopt a plurality of annular interdigital structures with different diameters, and all the annular interdigital structures are arranged in concentric manner; the line width of the interdigital microelectrodes is 0.2-0.3 mm, and the thickness of the interdigital microelectrodes is 0.5-0.6 mm.

3. The wearable flexible pressure sensor of claim 1, wherein: The spacer layer is in a ring structure, and the thickness of the spacer layer is 200-300 μm, and the ring width of the spacer layer is 5-6 mm.

4. The wearable flexible pressure sensor of claim 1, wherein: The pyramid-shaped microstructure is etched on the TPU film, and the pyramid-shaped microstructure comprises a plurality of pyramid monomers with different sizes and in random and irregular distribution.

5. The wearable flexible pressure sensor of claim 1, wherein: The encapsulation layer is made of PDMS material, and a concave-convex groove microstructure is formed on the surface of the encapsulation layer; the convex width of the groove microstructure is 2-3 μm, and the interval between adjacent convexes in the groove microstructure is 2-3 μm.

6. An underwater physiological information monitoring system characterized by: The wearable flexible pressure sensor is capable of being worn on the wrist of a person underwater as a data acquisition module. The underwater physiological information monitoring system further comprises a central control module and an alarm module, the data acquisition module is connected with the central control module, and the central control module is connected with the alarm module; The data acquisition module is used for real-time monitoring and real-time transmission of underwater physiological information; the central control module is used for data processing and judging whether an alarm signal should be output at present, and an alarm signal is sent if the detection data exceeds a safety threshold; and the alarm module is used for receiving the alarm signal from the central control module in real time and making a warning response.

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