A high-performance flexible wearable pressure acquisition device combined with a bionic scale structure to fit the skin

Abstract

The application discloses a high-performance flexible wearable pressure collecting device combined with bionic scale structure and attached to skin, and relates to the technical field of flexible sensors.The device comprises a flexible main body, which comprises a first encapsulating layer, a second encapsulating layer, an electrode layer and two flexible PI layers, the two flexible PI layers are respectively arranged on the upper and lower sides of the electrode layer, and the first encapsulating layer and the second encapsulating layer are respectively bonded with the corresponding flexible PI layer.The scale microstructure, the flexible PI layer, the elastic member and the first encapsulating layer are arranged, so that the PDMS base of the first encapsulating layer instead of the scale tip which produces a "point-like" compression feeling contacts the skin, which not only provides uniform support, eliminates any discomfort or indentation risk and meets the long-term wearing requirement, but also retains the amplification effect of the scale microstructure on slight pressure; and the elastic member becomes the main component for absorbing macroscopic deformation (such as joint bending and skin stretching).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible sensor, in particular to a high-performance flexible wearable pressure acquisition device combined with bionic scale structure and attached to skin. BACKGROUND

[0002] As a core component of modern flexible electronic technology, the flexible pressure sensor mainly converts mechanical pressure signals into detectable electrical signals to achieve accurate monitoring and feedback of pressure. The skin-attached flexible pressure sensor is based on ultra-thin flexible materials and can be closely attached to human skin or complex curved surfaces to achieve non-invasive monitoring. Its functions cover health monitoring (such as heart rate, respiration, and blood pressure analysis), motion posture optimization (step frequency, gait, and muscle force monitoring), human-computer interaction (gesture recognition and tactile feedback), and medical rehabilitation (wound pressure monitoring and neural training).

[0003] However, most flexible sensors are difficult to completely attach to human skin (especially in joint and curved areas), which not only affects the detection accuracy of the sensor, but also causes discomfort due to long-term wear.

[0004] In addition, the detection lower limit of most flexible sensors is above 1kPa, which cannot accurately detect weak physiological signals (such as pulse wave, muscle microtremor, and skin surface fine touch), limiting their application in high-precision medical diagnosis (such as early Parkinson's disease tremor monitoring) and bionic robot tactile feedback.

[0005] A flexible piezoelectric sensor with fish scale microstructure elastomer packaging and its preparation method are disclosed in Chinese patent CN202510519565.9. The invention optimizes the stress distribution of the elastomer packaging layer by setting the fish scale microstructure, so that the composite packaging structure of the first packaging layer and the elastomer packaging layer can guide the stress to concentrate in a specific area, enhance the local strain ability and reduce energy dissipation. At the same time, through the array distribution of multiple fish scale microstructure units, the sensitivity and response speed of the flexible piezoelectric sensor under low pressure or low frequency conditions are further improved.

[0006] However, when the sensor is used for large pressure range monitoring or encounters bending deformation, the contradiction between sensitivity and linear range will be further intensified, i.e. the closely arranged microstructure can achieve high sensitivity under low pressure due to stress concentration effect (such as fish scale tip contact), but under high pressure (>20kPa), such as joint movement or neck deviation, the microstructure unit will deform under the stretching of the flexible sensor, and the "point contact" of the fish scale tip will change to "surface contact" during the deformation process, resulting in saturation of the contact area and a sharp drop in sensitivity or even signal distortion.

[0007] And, since the "fish scale tip" of the above-mentioned sensor is directly in contact with the skin, such arrangement, although it can improve the detection accuracy of the sensor to the slight pressure, is prone to cause the skin to form a depression under long-time wearing, greatly reducing the wearing comfort.

[0008] To this end, the present application proposes a high-performance flexible wearable pressure acquisition device combined with a bionic scale structure to fit the skin to solve the above-mentioned problems. SUMMARY

[0009] The present application aims to provide a high-performance flexible wearable pressure acquisition device combined with a bionic scale structure to fit the skin to solve the technical problems raised in the background art.

[0010] To achieve the above-mentioned purpose, the present application provides the following technical solution: a high-performance flexible wearable pressure acquisition device combined with a bionic scale structure to fit the skin, comprising a flexible main body, the flexible main body comprising a first encapsulation layer, a second encapsulation layer, an electrode layer and two flexible PI layers, a metal film for conducting electricity being evaporated on the flexible PI layer, the two flexible PI layers being respectively located on the upper and lower sides of the electrode layer, and the first encapsulation layer and the second encapsulation layer being respectively bonded with the corresponding flexible PI layer.

[0011] The first encapsulation layer comprises a PDMS substrate, and a scale microstructure is arranged on the side of the PDMS substrate close to the flexible PI layer, the scale microstructure comprising a plurality of bionic scales.

[0012] Preferably, the plurality of bionic scales are distributed in an array or staggered array.

[0013] Preferably, the bionic scale is a semi-ellipsoidal body, the cross-sectional width of which changes continuously along the height direction, and each bionic scale has an arc-shaped outer surface without sharp protrusions for contacting the flexible PI layer.

[0014] Preferably, the first encapsulation layer further comprises a plurality of spaced-apart cluster units, each cluster unit being composed of at least one bionic scale, and an elastic member being arranged between adjacent cluster units, the elastic modulus of the elastic member being less than the elastic modulus of the bionic scale, and when the flexible main body is stretched, the plurality of elastic members are deformed and expand the spacing of the plurality of cluster units.

[0015] Preferably, a movable gap is formed between adjacent elastic members, and the cross-sectional area of the movable gap changes when the elastic member is elastically deformed.

[0016] Preferably, the material of the elastic member is consistent with the PDMS substrate of the first encapsulation layer.

[0017] Preferably, the elastic member is an elastic band, and the two ends of the elastic band are respectively fixedly connected with the bionic scales in the adjacent cluster units.

[0018] Preferably, the flexible PI layer is provided with a hydrophobic coating on the side close to the scale microstructure, and a flexible waterproof layer is arranged between the scale microstructure and the flexible PI layer.

[0019] Preferably, a signal acquisition circuit is arranged on the electrode layer, and the signal acquisition circuit comprises a signal amplification circuit and a filter circuit.

[0020] Preferably, the flexible main body circumscribes a data storage conversion device, the data storage conversion device comprises an ADC conversion module, a single-chip microcomputer and a Bluetooth module, the signal acquisition circuit outputs a signal to the ADC conversion module, and the ADC conversion module converts the signal into a digital signal.

[0021] The beneficial effects of the present application are:

[0022] The present application is provided with a scale microstructure, a flexible PI layer, an elastic member and a first encapsulation layer, and the first encapsulation layer PDMS substrate instead of the scale tip that produces a "point-like" compression feeling when contacting the skin, which not only provides uniform support, eliminates any risk of discomfort or indentation and meets the needs of long-term wear, but also retains the amplification effect of the scale microstructure on micro pressure; and the elastic member becomes the main component for absorbing macro deformation (such as joint bending and skin stretching), when the sensor is stretched, the stress is preferentially released through the extension or bending of the elastic member, while the biomimetic scale itself and its contact tip with the flexible PI layer remain relatively stable, the morphology and inclination angle of the biomimetic scale do not change due to overall stretching, and the stress concentration effect of the biomimetic scale on micro pressure is always at the optimal working point. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a cross-sectional view of the high-performance flexible wearable pressure acquisition device of the present application combined with a biomimetic scale structure attached to the skin.

[0024] Figure 2 It is a perspective view of the high-performance flexible wearable pressure acquisition device of the present application combined with a biomimetic scale structure attached to the skin.

[0025] Figure 3 It is a planar structure diagram of the biomimetic scale in the first encapsulation layer of the present application.

[0026] Figure 4 It is a perspective structure diagram of the biomimetic scale in the first encapsulation layer of the present application.

[0027] Figure 5 It is a cooperation diagram of the cluster unit and the elastic member in the first encapsulation layer of the present application.

[0028] Figure 6 It is a signal amplification circuit diagram of the present application.

[0029] Figure 7 The schematic diagram of the filter circuit in the application.

[0030] Reference signs are:

[0031] 1, flexible body; 11, first encapsulation layer; 111, PDMS substrate; 112, bionic scale; 12, second encapsulation layer; 13, electrode layer; 14, flexible PI layer;

[0032] 2, cluster unit;

[0033] 3, elastic member. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person skilled in the art without creative labor fall within the protection scope of the application.

[0035] Embodiment 1

[0036] Since the detection lower limit of most existing flexible sensors is basically above 1 kPa, the weak physiological signals cannot be accurately detected, which greatly affects the application of the flexible sensor in high-precision medical diagnosis. Although some existing technologies use the bionic structure of "fish scales" to improve the sensitivity and response speed of the sensor under low pressure or low frequency conditions, the "fish scale tip" of the sensor directly contacts the skin. Although this setting can improve the detection accuracy of the sensor to the micro pressure, it is easy to form a depression on the skin under long-term wearing, which greatly reduces the wearing comfort. To solve the above problems, the embodiment is invented.

[0037] Please refer to Figures 1 to 7 As shown in the figure, an embodiment of the application is a high-performance flexible wearable pressure acquisition device combined with bionic scale structure and attached to the skin, which comprises a flexible body 1. The flexible body 1 comprises a first encapsulation layer 11, a second encapsulation layer 12, an electrode layer 13 and two flexible PI layers 14. The flexible PI layer 14 is coated with a metal film for conduction. The two flexible PI layers 14 are respectively located on the upper and lower sides of the electrode layer 13. The first encapsulation layer 11 and the second encapsulation layer 12 are respectively bonded to the corresponding flexible PI layer 14.

[0038] Please refer to Figure 6 and Figure 7As shown, the signal acquisition circuit is arranged on the electrode layer 13, and the signal acquisition circuit includes a signal amplification circuit and a filter circuit. The signal amplification circuit can amplify the pressure signal collected by the sensor to a signal strength suitable for single-chip microcomputer collection. The main purpose of the filter circuit is to remove the noise of the original signal and reduce the influence of noise on the signal.

[0039] The flexible main body 1 is externally connected to a data storage conversion device, which includes an ADC conversion module, a single-chip microcomputer, and a Bluetooth module. The signal acquisition circuit outputs a signal to the ADC conversion module, which converts the signal into a digital signal and sends it to the single-chip microcomputer. The single-chip microcomputer processes the digital piezoelectric signal and transmits the processed data to an APP or an upper computer through the Bluetooth module.

[0040] Please refer to Figures 2 to 4 As shown, the first packaging layer 11 includes a PDMS substrate 111, and the side of the PDMS substrate 111 close to the flexible PI layer 14 is provided with a scale microstructure, which includes a plurality of bionic scales 112.

[0041] Please refer to Figure 3 As shown, the plurality of bionic scales 112 are arranged in an array or an interlaced array.

[0042] Please refer to Figure 4 As shown, the bionic scale 112 is a semi-ellipsoidal body, and the cross-sectional width thereof changes continuously along the height direction, and each bionic scale 112 has an arc-shaped outer surface without sharp protrusions for contacting the flexible PI layer 14.

[0043] It should be noted that when the flexible main body 1 is designed, the front and back surfaces of the flexible main body 1 can contact the skin and perform pressure detection, that is, the first packaging layer 11 and the second packaging layer 12 in the embodiment can contact the skin. In the conventional detection, that is, without the need to improve the detection of small pressure, for example, the flexible main body 1 is attached to the joint for pressure detection. In the embodiment, the detection mode of the sensor is described by taking the contact between the first packaging layer 11 and the skin of the neck as an example.

[0044] In the embodiment, the electrode layer 13 is a silver-plated PVDF film, and the preparation method thereof includes the following steps: cutting a silver-plated PVDF film into a specified size, in the embodiment, the size of the silver-plated PVDF film is 11mm x 11mm, then cleaning with anhydrous ethanol to remove burrs around to prevent short circuit, then cleaning with ultrapure water to remove residual anhydrous ethanol on the surface, and then blowing dry with a nitrogen gun after cleaning, and checking whether the film is short-circuited by a multimeter.

[0045] The material of the second encapsulation layer 12 is consistent with the PDMS substrate 111 in the first encapsulation layer 11, and the preparation method of the PDMS substrate 111 and the first encapsulation layer 11 is supplemented as follows: the PDMS and the curing agent are mixed at a mass ratio of 10:1, and after stirring until the mixture is white and bubbles are dense (indicating that the mixture is uniformly mixed to form a prepolymer), the prepolymer is placed in a vacuum dryer for 10 minutes to remove bubbles; after the bubbles completely disappear, the prepolymer is injected into a 3D printing mold with the bionic scale 112 structure, and placed in an oven for heating and curing at 60°C for 6 hours.

[0046] In another embodiment, in order to improve the elastic modulus of the bionic scale 112, the scale microstructure and the PDMS substrate 111 can also be prepared separately, and then the scale microstructure and the PDMS substrate 111 are bonded and fixed.

[0047] In addition, the flexible PI layer 14 in this embodiment is a copper-plated PI, and the preparation method thereof includes: using an evaporation machine to plate a copper film with a thickness of 150 nm on a flexible PI substrate, cutting it to a specified size, and then washing it with anhydrous ethanol and ultrapure water to remove impurities, thereby obtaining the flexible PI layer 14.

[0048] The preparation method of the flexible main body 1 is supplemented as follows: after two pieces of the flexible PI layer 14 are bonded to the front and back sides of the electrode layer 13 using conductive silver glue, they are placed in an oven at a temperature of 40°C for 3 minutes to activate the conductivity of the conductive silver glue, and then left to cure at room temperature for 24 hours. Finally, the first encapsulation layer 11 and the second encapsulation layer 12 are bonded and fixed to the corresponding flexible PI layer 14. It should be noted that there is a gap between the first encapsulation layer 11 and the adjacent flexible PI layer 14 due to the scale microstructure, which is a normal phenomenon and does not need to be treated.

[0049] In use, the flexible main body 1 is fixed at a detection position of the human body, and the first encapsulation layer 11 is in contact with the skin. At this time, the PDMS substrate 111 is in "surface contact" with the skin, and the scale microstructure is in "point contact" with the flexible PI layer 14. When the skin applies a small pressure, the force will be transmitted to each bionic scale 112 through the flat PDMS substrate 111, and since the scale itself is similar to a cantilever beam structure, the force will be conducted along the inclined surface of the scale and finally form a high stress concentration at the tip.

[0050] That is, the inclined structure of the scale actually plays a role similar to a "lever", which can amplify the small pressure received by the substrate surface into more significant and more local extrusion deformation of the flexible PI layer 14 and the electrode layer 13 at the tip, thereby improving the detection of the sensor on the small pressure.

[0051] In summary, through the arrangement of the scale microstructure, the flexible PI layer 14 and the first encapsulation layer 11, the skin is in contact with the PDMS base 111 of the first encapsulation layer 11 instead of the scale tip which produces a “point” compression feeling. This not only provides uniform support, eliminates any risk of discomfort or indentation and meets the needs of long-term wear, but also retains the amplification effect of the scale microstructure on slight pressure and makes the scale microstructure “wrapped” inside the PDMS base 111 and the flexible PI layer 14, avoiding the risk of damage or permanent deformation due to direct scratching or collision, and improving the durability of the sensor.

[0052] Embodiment 2

[0053] The existing sensor will further exacerbate the contradiction between sensitivity and linear range when monitoring a large pressure range or encountering bending deformation, that is, the closely arranged microstructure can achieve high sensitivity due to stress concentration effect (such as fish scale tip contact) at low pressure, but in the case of high pressure (> 20kPa), such as joint movement or neck deviation, the microstructure unit will be deformed under the stretching of the flexible sensor, and the “point contact” of the fish scale tip will become “face contact” during the deformation process, resulting in saturation of the contact area, and thus a sharp drop in sensitivity and even signal distortion. Further improvements are made on the basis of the above embodiments.

[0054] Please refer to Figure 4 As shown in the figure, the first encapsulation layer 11 further comprises a plurality of spaced cluster units 2, the cluster unit 2 is composed of at least one bionic scale 112, and an elastic member 3 is arranged between adjacent cluster units 2, and the elastic modulus of the elastic member 3 is less than the elastic modulus of the bionic scale 112. When the flexible main body 1 is stretched, the plurality of elastic members 3 are deformed and the spacing of the plurality of cluster units 2 is expanded.

[0055] An active gap is formed between adjacent elastic members 3, and the cross-sectional area of the active gap changes when the elastic member 3 is elastically deformed.

[0056] The material of the elastic member 3 is consistent with the PDMS base 111 of the first encapsulation layer 11.

[0057] In this embodiment, the elastic member 3 is an elastic band, and the two ends of the elastic band are fixedly connected with the bionic scales 112 in the adjacent cluster units 2.

[0058] In another embodiment, the PDMS base 111 can also be used as the elastic member 3, that is, the cluster units 2 are arranged at equal intervals, and the PDMS base 111 is connected between adjacent cluster units 2, and the elastic modulus of the PDMS base 111 is less than the elastic modulus of the cluster unit 2.

[0059] On the basis of the above embodiments, in use, when the flexible main body 1 is worn on the detection site, taking the neck as an example, when the wearer's head is laterally tilted and causes the flexible main body 1 to stretch, because the elastic modulus of the elastic member 3 is smaller than that of the scale microstructure, the elastic stress is preferentially released by the extension or bending of the elastic member 3, and the scale unit itself and the contact points with the PI layer remain relatively stable.

[0060] Moreover, based on the active gap formed between the plurality of elastic members 3, the sweat excreted by the wearer during the activity can also be discharged from the active gap. When the human body movement is intensified and the amount of sweat increases, and the sensor is stretched due to limb activity, the active gap becomes larger, forming a wider sweat discharge channel.

[0061] In summary, through the arrangement of the elastic member 3, the active gap, and the cluster unit 2, etc., the elastic member 3 becomes the main component that absorbs macroscopic deformation (such as joint bending and skin stretching). When the sensor is stretched, the stress is preferentially released by the extension or bending of the elastic member 3, and the contact tips of the biomimetic scale 112 and the flexible PI layer 14 remain relatively stable. The morphology and inclination angle of the biomimetic scale 112 do not change due to overall stretching, and the stress concentration effect of the biomimetic scale 112 to micro-pressure is always at the optimal working point. Moreover, the active gap naturally formed by the elastic member 3 is used as a sweat discharge channel that can be dynamically adjusted with stretching, which can more efficiently discharge sweat and heat, fundamentally eliminating problems such as "stuffy" and "eczema", and greatly improving the wearing time of the sensor.

[0062] Embodiment 3

[0063] Considering that when the first packaging layer 11 is in direct contact with the flexible PI layer 14, the sweat produced by the human body can directly enter the scale microstructure through the active gap. When the wearer's movement is large or the wearing time is long, the amount of sweat accumulation is large, and at this time the metal in the flexible PI layer 14 will be eroded by the sweat, which may cause the detection accuracy to decrease or the sensor to malfunction. In order to avoid or improve the above problems, this embodiment is proposed.

[0064] The side of the flexible PI layer 14 close to the scale microstructure is provided with a hydrophobic coating, and a flexible waterproof layer is arranged between the scale microstructure and the flexible PI layer 14.

[0065] Further, in order to further improve the protection level of the flexible PI layer 14, in other embodiments, the metal of the flexible PI layer 14 is an inert metal, and even if the sweat passes through the flexible waterproof layer and the hydrophobic coating, it is difficult to cause corrosion to the metal.

[0066] In summary, by setting the hydrophobic coating and the flexible waterproof layer, not only the perspiration function of the first packaging layer 11 is reserved, but also the erosion of the sweat to the flexible PI layer 14 is avoided, and the influence of the flexible PI layer 14 due to the large amount of sweat of the wearer is improved or even avoided.

[0067] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solutions and the inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A high-performance flexible wearable pressure acquisition device that incorporates a biomimetic scale structure to conform to the skin, characterized in that, The device includes a flexible body, which comprises a first encapsulation layer, a second encapsulation layer, an electrode layer, and two flexible PI layers. A conductive metal film is deposited on the flexible PI layers. The two flexible PI layers are located on the upper and lower sides of the electrode layer, respectively. The first encapsulation layer and the second encapsulation layer are respectively bonded to the corresponding flexible PI layers. The first encapsulation layer includes a PDMS substrate, and a scale microstructure is disposed on the side of the PDMS substrate near the flexible PI layer. The scale microstructure includes a plurality of biomimetic scales. The first encapsulation layer further includes multiple spaced cluster units, each cluster unit consisting of at least one biomimetic scale, and an elastic element is provided between adjacent cluster units. The elastic modulus of the elastic element is less than that of the biomimetic scale. When the flexible body is stretched, the multiple elastic elements deform and the spacing between the multiple cluster units increases.

2. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The biomimetic scales are arranged in an array.

3. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The biomimetic scales are arranged in an alternating array.

4. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The biomimetic scales are semi-ellipsoidal, with their cross-sectional width continuously varying along the height direction, and each biomimetic scale has an arched outer surface without sharp protrusions for contacting the flexible PI layer.

5. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... An movable gap is formed between adjacent elastic elements. When the elastic elements undergo elastic deformation, the cross-sectional area of ​​the movable gap changes accordingly.

6. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The material of the elastic element is the same as that of the PDMS substrate of the first encapsulation layer.

7. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The elastic element is an elastic band, and the two ends of the elastic band near the adjacent cluster unit are respectively fixedly connected to the biomimetic scales therein.

8. The high-performance flexible wearable pressure acquisition device according to claim 1, which incorporates a biomimetic scale structure to conform to the skin, is characterized in that... The flexible PI layer has a hydrophobic coating on the side close to the scale microstructure, and a flexible waterproof layer is provided between the scale microstructure and the flexible PI layer.

9. A high-performance flexible wearable pressure acquisition device combining a biomimetic scale structure with skin conformability, as described in claim 1, is characterized in that... A signal acquisition circuit is provided on the electrode layer, and the signal acquisition circuit includes a signal amplification circuit and a filtering circuit.

10. A high-performance flexible wearable pressure acquisition device combining a biomimetic scale structure with skin conformability, as described in claim 9, is characterized in that... The flexible main body is connected to an external data storage and conversion device, which includes an ADC conversion module, a microcontroller, and a Bluetooth module. The signal acquisition circuit outputs a signal to the ADC conversion module, which converts the signal into a digital signal.

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