A high-sensitivity flexible pulse sensor and preparation method thereof

Abstract

The present invention relates to a highly sensitive flexible pulse sensor and a preparation method thereof, comprising the steps of: S1, printing a layer of elastic polymer film on an elastic fabric substrate; S2, printing flexible electrodes on the elastic polymer film; S3, preparing an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface; and S4, using a flexible packaging process to package the elastic functional fabric and the elastic fabric substrate printed with the flexible electrodes to form a highly sensitive flexible pulse sensor. The preparation process of the highly sensitive flexible pulse sensor of the present invention is simple and fast, with low cost, and is suitable for batch production and preparation. The sensor is based on an elastic fabric substrate and a highly sensitive and highly elastic elastic functional fabric, has good flexibility, good adhesion, and is breathable. The sensor can be worn on the body and fits the skin, and can realize highly sensitive perception and monitoring of physiological monitoring signals such as pulse and heart rate and motion signals such as muscle movement dimensions, with accurate data.

Description

Technical Field

[0001] The invention relates to the technical field of flexible pressure sensor preparation, and in particular to a high-sensitivity flexible pulse sensor and a preparation method thereof. Background Art

[0002] Physiological parameters such as pulse and heart rate are important vital signs of the human body and can reflect many physiological diseases. They are not only of great significance to the elderly and heart patients, but also very necessary for athletes who love physical exercise. Cases of sudden death and cardiac arrest during exercise often occur every year. If you use pulse and heart rate monitoring during exercise, you can quickly and clearly reflect the information of the body during exercise, so that the exercise intensity can be kept within an appropriate range to achieve the best exercise effect. Currently, the commonly used detections are mainly hospital instruments and equipment, which have problems such as being unportable and inconvenient for personal use. Portable devices are mainly smart watches and bracelets based on photoelectric sensors. These are still traditional rigid devices. The poor adhesion affects the wearing experience, and the monitoring accuracy is affected by sweat, vibration, exercise posture, physical condition, etc. during exercise. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a highly sensitive sensor that has good adhesion, is breathable, and can be worn on the body and fits the skin to realize the perception of physiological health signals such as pulse and heart rate and motion signals such as muscle movement dimensions.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A method for preparing a highly sensitive flexible pulse sensor comprises the following steps:

[0006] S1. printing a layer of elastic polymer film on an elastic fabric substrate;

[0007] S2, printing a flexible electrode on the elastic polymer film;

[0008] S3, preparing elastic functional fabrics with highly sensitive nano-sensitive materials attached to the surface;

[0009] S4. Using a flexible packaging process, the elastic functional fabric and the elastic fabric substrate printed with flexible electrodes are packaged to form a highly sensitive flexible pulse sensor.

[0010] Furthermore, the step S3 includes the following steps:

[0011] S31, preparing a carbon nanomaterial dispersion, dissolving 0.01%-0.2% of the carbon nanomaterial by mass into a dispersant, and uniformly dispersing the carbon nanomaterial by ultrasonication for 0.1-2h to obtain a carbon nanomaterial dispersion;

[0012] S32, preparing an elastic polymer solution, dissolving 0.2%-2% of the elastic polymer by mass into a dispersant, stirring for 0.1-3h, and preparing an elastic polymer solution;

[0013] S33, preparing a nanocomposite functional material, mixing the carbon nanomaterial dispersion and the elastic polymer solution for 0.5-2h, and ultrasonicating for 0.1-2h to prepare a uniformly dispersed nanocomposite functional material;

[0014] S34, pretreating the elastic yarn by soaking the elastic yarn in an ethanol solution for 1-60 minutes;

[0015] S35, dyeing the elastic yarn, passing the pretreated elastic yarn through a dyeing device containing the elastic polymer solution at a certain speed, and then subjecting the pretreated elastic yarn to a semi-cured state through a thermal curing treatment;

[0016] S36, roughening the elastic yarn, the elastic yarn obtained in the above step S35 is subjected to roughening treatment to make the surface of the semi-cured elastic polymer uneven;

[0017] S37, secondary dyeing of the elastic yarn, passing the elastic yarn obtained in the above step S36 through a dyeing device containing the nanocomposite functional material at a certain speed so that a layer of nanocomposite material is attached to the surface of the elastic yarn, and then undergoing a thermal curing treatment to prepare an elastic yarn with the nanocomposite functional material attached to the surface. This step can be repeated several times according to actual needs;

[0018] S38, three-time dip-dyeing the elastic yarn, attaching an elastic encapsulation layer on the surface of the functional elastic yarn obtained in step S37 by dip-dyeing process;

[0019] S39, weaving, using a loom weaving process to weave the elastic yarn with the nano-composite functional material attached as weft yarn and ordinary yarn as warp yarn to obtain an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface.

[0020] Furthermore, the carbon nanomaterial is carbon nanotube, graphene or reduced graphene oxide RGO.

[0021] Furthermore, the dispersant is anhydrous ethanol, N,N-dimethylformamide or cyclohexane.

[0022] Furthermore, the elastic polymer is TPU, TPE, PDMS or silica gel.

[0023] Furthermore, the elastic polymer film is formed by printing TPU, TPE, PDMS or silicone slurry on the elastic fabric substrate and curing the slurry.

[0024] Furthermore, the flexible packaging process uses hot pressing or bonding to perform flexible packaging.

[0025] A highly sensitive flexible pulse sensor is prepared according to the above-mentioned method for preparing a highly sensitive flexible pulse sensor, and comprises an elastic fabric substrate, an elastic polymer film layer, a flexible electrode layer and an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface.

[0026] The invention prepares a highly sensitive flexible pulse sensor by printing a layer of elastic polymer film on an elastic fabric substrate, then printing a flexible electrode on the elastic polymer film layer, and then using a flexible packaging process to package the elastic fabric substrate and the elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface. The preparation process is simple, fast, low-cost, and suitable for mass production.

[0027] The high-sensitivity flexible pulse sensor of the present invention adopts an elastic fabric base and a highly sensitive and highly elastic elastic functional fabric as its basis. It has good flexibility, good fit performance, and is breathable. It fits the skin when worn on the body. It can realize highly sensitive perception and monitoring of physiological monitoring signals such as pulse and heart rate and motion signals such as muscle movement dimensions, and the data is accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention provides a preparation process for the highly sensitive flexible pulse sensor.

[0029] Figure 2 This is a structural diagram of the highly sensitive flexible pulse sensor of the present invention.

[0030] Figure 3 The invention discloses a preparation process of an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface.

[0031] Figure 4 This is a structural diagram of the elastic functional fabric with highly sensitive nano-sensitive materials attached to the surface of the present invention.

[0032] Figure 5 FIG. 4 is a circuit diagram of the pulse monitoring system of the present invention.

[0033] Figure 6 This is a pulse variation curve graph collected by the highly sensitive flexible pulse sensor of the present invention.

[0034] Wherein: 1. elastic fabric substrate, 2. elastic polymer film layer, 3. flexible electrode layer, 4. elastic functional fabric, 401. elastic yarn, 402. elastic polymer layer, 403. nano-composite functional material layer, 404. elastic encapsulation layer. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0037] A highly sensitive flexible pulse sensor, such as Figure 2 As shown, it includes an elastic fabric substrate 1, an elastic polymer film layer 2, a flexible electrode layer 3 and an elastic functional fabric 4 with a highly sensitive nano-sensitive material attached to the surface. The elastic polymer film layer 2 is formed by printing and curing an elastic polymer film slurry on the elastic fabric substrate, and the elastic polymer film layer 2 provides a dense support for the flexible electrode layer 3. The flexible electrode layer is formed by printing and curing a patterned conductive slurry on the elastic polymer film layer. The elastic fabric substrate and the elastic functional fabric are bonded and packaged through a flexible packaging process to prepare a highly sensitive flexible pulse sensor of the present invention. Among them, the flexible electrode layer 3 includes a sensing area and a lead, and the sensing area includes but is not limited to a forked finger shape or a spiral shape, or an arrayed sensing area. The lead is connected to the monitoring system to realize signal transmission, and the flexible electrode layer 3 is in contact with the elastic functional fabric 4 to realize electrical connection and signal transmission.

[0038] like Figure 1 As shown, the preparation method thereof comprises the following steps:

[0039] S1. Printing a layer of elastic polymer film on the elastic fabric substrate. The elastic polymer film can achieve good elasticity on one hand, and provide dense support for the flexible electrode on the other hand. The elastic polymer film is formed by printing TPU, TPE, PDMS or silicone slurry on the elastic fabric substrate and curing it;

[0040] S2. Printing a flexible electrode on the elastic polymer film. The flexible electrode is a patterned flexible electrode, including but not limited to a forked finger-shaped electrode, a spiral-shaped electrode, etc., which can be customized according to specific needs. The flexible electrode includes a sensing area and a lead. The sensing area corresponds to the elastic functional fabric of the highly sensitive nano-sensitive material to sense pressure, and the signal is led out and fed back through the lead;

[0041] S3, preparing elastic functional fabrics with highly sensitive nano-sensitive materials attached to the surface;

[0042] S4. Using a flexible packaging process, the elastic functional fabric and the elastic fabric substrate printed with flexible electrodes are packaged to form a highly sensitive flexible pulse sensor.

[0043] Among them, step S3 is a method for preparing an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface, such as Figure 2 As shown, the following steps are included:

[0044] S31. Prepare a carbon nanomaterial dispersion, dissolve the carbon nanomaterial (mass fraction of 0.01%-0.2%) in a dispersant, and mix it thoroughly by ultrasonication at a power of 50-300w for 0.1-2h to prepare a 1-1.5mg / ml carbon nanomaterial uniform dispersion. The carbon nanomaterial can be carbon nanotubes, graphene, reduced graphene oxide RGO, etc., and the dispersant can be anhydrous ethanol, N,N-dimethylformamide, cyclohexane, etc.

[0045] S32, prepare elastic polymer solution, dissolve elastic polymer (mass fraction 0.2%-2%) in dispersant, stir for 0.1~3h, and prepare 10-15mg / ml elastic polymer solution. Elastic polymer can be TPU, TPE, PDMS, silica gel, etc., dispersant can be anhydrous ethanol, N,N-dimethylformamide, cyclohexane, etc.

[0046] S33, preparing a nanocomposite functional material, fully mixing and stirring the above carbon nanomaterial dispersion and the above elastic polymer solution for 0.5-2h, and ultrasonicating at a power of 100-300W for 0.1-2h to prepare a uniformly dispersed nanocomposite functional material. The nanocomposite functional material of the present invention not only has good flexibility and elasticity, but also has good electrical and chemical properties.

[0047] S34, pre-treating the elastic yarn by soaking the elastic yarn in an ethanol solution for 1-60 minutes to pre-treat the elastic yarn so that the surface of the elastic yarn has functional groups, which are convenient for combining with the functional groups in the elastic polymer solution.

[0048] S35, dyeing the elastic yarn, passing the pretreated elastic yarn through a dyeing device containing the elastic polymer solution at a certain speed, and then subjecting the yarn to a heat curing treatment (drying in a heating device at 50-120°C for 0.1-2h) to make it in a semi-cured state, so as to enhance the adhesion firmness and stability of the nano-composite functional material layer and the elastic polymer layer in the subsequent process of dyeing the nano-composite functional material.

[0049] S36, roughening the elastic yarn. The elastic yarn obtained in S35 is roughened (immersed in an ethanol solution for 1-60 min) to make the surface of the semi-cured elastic polymer uneven, thereby further enhancing the adhesion and stability between the nano-composite functional material layer and the elastic polymer layer.

[0050] S37, secondary dyeing of the elastic yarn, passing the elastic yarn obtained in S36 through a dyeing device containing the nano-composite functional material at a certain speed so that a layer of nano-composite functional material adheres to its surface, and then undergoing a thermal curing treatment (drying in a heating device at 50-120°C for 0.1-2h) to solidify it to obtain an elastic yarn with the nano-composite functional material adhered to its surface. This step can be repeated several times according to actual needs to fully dye its surface, so as to improve the flexibility and mechanical properties of the elastic yarn.

[0051] S38, three-time dip-dyeing of the elastic yarn, the functional elastic yarn obtained in S37 can be further dip-dyed to attach an elastic packaging layer on its surface according to needs.

[0052] S39, weaving, using a loom weaving process, using the elastic yarn with the nano-composite functional material attached to the surface as prepared as above as weft yarn and ordinary yarn as warp yarn to weave into a large area of ​​elastic functional fabric with the highly sensitive nano-sensitive material attached to the surface.

[0053] S310, cutting, assembling and preparing the flexible pulse sensor. According to the size of the sensor, it is necessary to cut the elastic functional fabric of appropriate size from the large area elastic fabric prepared in S39 for subsequent fitting and assembly.

[0054] like Figure 4 As shown, it is a structural diagram of the elastic yarn with a highly sensitive nano-composite functional material attached to the surface, which is prepared according to the above steps S31-S38, including an elastic yarn 401, an elastic polymer layer 402, a nano-composite functional material layer 403 and an elastic packaging layer 404 attached and wrapped in sequence to the elastic yarn 401. The elastic polymer layer 402 can enhance the flexibility and mechanical properties of the elastic yarn, the nano-composite functional material layer 403 can further enhance the flexibility and mechanical properties of the elastic yarn, and at the same time provide a highly sensitive sensitive material, and the elastic packaging layer 404 serves as a protective layer.

[0055] The highly sensitive flexible pulse sensor of the present invention can be integrated onto a wrist guard, a sports vest, etc. by means of physical contact (sewing, hot pressing, pasting, etc.), and is easy to wear and use.

[0056] In order to achieve highly sensitive monitoring of physiological health signals such as pulse and heart rate, the present invention also provides a monitoring system, including an analog signal extraction module, an analog signal amplification module, an AD conversion module and an MCU processor. The analog signal extraction module is used to convert the resistance signal of the sensor into a voltage signal, and then extract the AC component in the voltage signal. The analog signal amplification module performs multi-stage operations to amplify the signal. The amplified analog signal is converted into a digital signal by the AD conversion module and transmitted to the MCU processor for algorithm monitoring and analysis. Based on the characteristic signal collected by the highly sensitive flexible pulse sensor, a signal conditioning amplification and digital signal processing system (including analog amplifiers, AD converters, digital signal processing algorithms and low-power hardware systems) and peripheral function modules (wireless communication function, wireless charging function module, display control module) are manufactured through the extraction and processing of the collected signal, circuit system and digital signal processing algorithm.

[0057] In terms of system algorithms, the monitoring system plans to adopt single-channel and multi-channel, fast-response digital phase-locked amplification related signal detection methods to achieve weak signal extraction in a low signal-to-noise ratio environment; array multi-channel switching is used to reduce the hardware scale of the signal channel, while having low voltage and low power consumption to adapt to different working conditions, and assisting flexible thin-film batteries to achieve automatic power management to improve battery life; the communication part will use the serial communication mode of the sensor array networking protocol to achieve wireless transmission to the display control module to display the monitored pulse waveform, heart rate and other physiological parameters.

[0058] like Figure 5 As shown in the figure, it is the pulse monitoring circuit diagram of the present invention. After the flexible pulse pressure sensor on the left senses the pressure, its resistance value will change with the pressure fluctuation caused by the pulse beating. In this acquisition circuit, the sensor signal is first connected to the voltage divider circuit to convert the resistance signal into a voltage signal, and then the AC component in the voltage signal is extracted. After passing through the secondary operational amplifier circuit, it is sent to the ADC module, and the ADC module converts the analog quantity into a digital quantity. The MCU on the right reads the ADC module data through the communication interface and restores the waveform of the pulse fluctuation through the algorithm model.

[0059] like Figure 6 As shown, it is a pulse variation curve collected by the highly sensitive flexible pulse sensor of the present invention.

[0060] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a highly sensitive flexible pulse sensor, characterized in that: The following steps are involved: S1. Printing a layer of elastic polymer film on an elastic fabric substrate; the elastic polymer film is formed by printing TPU, TPE, PDMS or silicone slurry on the elastic fabric substrate and curing the slurry; S2, printing a flexible electrode on the elastic polymer film; S3, preparing elastic functional fabrics with highly sensitive nano-sensitive materials attached to the surface; S4, using a flexible packaging process to package the elastic functional fabric and the elastic fabric substrate printed with flexible electrodes to form a highly sensitive flexible pulse sensor; the flexible packaging process uses a hot pressing method or bonding to perform flexible packaging; The step S3 further comprises the following steps: S31, preparing a carbon nanomaterial dispersion, dissolving 0.01%-0.2% of the carbon nanomaterial by mass into a dispersant, and uniformly dispersing the carbon nanomaterial by ultrasonication for 0.1-2h to obtain a carbon nanomaterial dispersion; S32, preparing an elastic polymer solution, dissolving 0.2%-2% of the elastic polymer by mass into a dispersant, stirring for 0.1-3h, and preparing an elastic polymer solution; S33, preparing a nanocomposite functional material, mixing the carbon nanomaterial dispersion and the elastic polymer solution for 0.5-2h, and ultrasonicating for 0.1-2h to prepare a uniformly dispersed nanocomposite functional material; S34, pretreating the elastic yarn by soaking the elastic yarn in an ethanol solution for 1-60 minutes; S35, dyeing the elastic yarn, passing the pretreated elastic yarn through a dyeing device containing the elastic polymer solution at a certain speed, and then subjecting the pretreated elastic yarn to a semi-cured state through a thermal curing treatment; S36, roughening the elastic yarn, the elastic yarn obtained in the above step S35 is roughened to make the surface of the semi-cured elastic polymer uneven; S37, secondary dyeing of the elastic yarn, passing the elastic yarn obtained in the above step S36 through a dyeing device containing the nanocomposite functional material at a certain speed so that a layer of nanocomposite material is attached to the surface of the elastic yarn, and then subjecting the elastic yarn to a thermal curing treatment to obtain an elastic yarn with the nanocomposite functional material attached to the surface; S38, three-time dip-dyeing the elastic yarn, attaching an elastic encapsulation layer on the surface of the functional elastic yarn obtained in step S37 by dip-dyeing process; S39, weaving, using a loom weaving process to weave the elastic yarn with the nano-composite functional material attached as weft yarn and ordinary yarn as warp yarn to obtain an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface.

2. The method for preparing a highly sensitive flexible pulse sensor according to claim 1, characterized in that: The carbon nanomaterial is carbon nanotube, graphene or reduced graphene oxide RGO.

3. The method for preparing a highly sensitive flexible pulse sensor according to claim 1, characterized in that: The dispersant is anhydrous ethanol, N,N-dimethylformamide or cyclohexane.

4. The method for preparing a highly sensitive flexible pulse sensor according to claim 1, characterized in that: The elastic polymer is TPU, TPE, PDMS or silica gel.

5. A highly sensitive flexible pulse sensor, characterized in that: The method according to any one of claims 1 to 4 comprises an elastic fabric substrate, an elastic polymer film layer, a flexible electrode layer and an elastic functional fabric with a highly sensitive nano-sensitive material attached to the surface.

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