High-performance flexible wearable pressure acquisition device combined with bionic scale structure and attached to skin

Abstract

The invention discloses a skin-fitting high-performance flexible wearable pressure acquisition device combined with a bionic scale structure, and relates to the technical field of flexible sensors, the pressure acquisition device comprises a flexible main body, the flexible main body comprises a first packaging layer, a second packaging layer, an electrode layer and two flexible PI layers, the two flexible PI layers are respectively located on the upper and lower sides of the electrode layer, and the first packaging layer is connected with the second packaging layer. And the first packaging layer and the second packaging layer are respectively bonded with the corresponding flexible PI layers. Through the arrangement of the scale microstructure, the flexible PI layer, the elastic piece, the first packaging layer and the like, a scale tip which does not generate a point-shaped pressure feeling is in contact with the skin, but a PDMS substrate of the first packaging layer is adopted, so that uniform support is provided, any discomfort or indentation risk is eliminated, and the requirement of long-term wearing is met; the amplification effect of the scale microstructure on micro pressure is also reserved; in addition, the elastic piece becomes a 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. 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.

[0011] Preferably, the plurality of bionic scales are distributed in an array or staggered array.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] Preferably, the material of the elastic member is consistent with the PDMS substrate of the first encapsulation layer.

[0016] 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.

[0017] Preferably, a hydrophobic coating is arranged on the side of the flexible PI layer close to the scale microstructure, and a flexible waterproof layer is arranged between the scale microstructure and the flexible PI layer.

[0018] 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.

[0019] 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.

[0020] The beneficial effects of the present application are: The present application provides uniform support, eliminates any risk of discomfort or indentation and meets the needs of long-term wear, and retains the amplification effect of the scale microstructure on micro-pressure, by arranging the scale microstructure, the flexible PI layer, the elastic member and the first encapsulation layer, and the PDMS base of the first encapsulation layer contacts the skin instead of the scale tip which produces a "point-like" compression feeling, and the elastic member becomes the main component for absorbing macroscopic 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, and 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

[0021] Figure 1 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0022] Figure 2 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0023] Figure 3 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0024] Figure 4 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0025] Figure 5 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0026] Figure 6 FIG. 1 is a cross-sectional view of a high-performance flexible wearable pressure acquisition device according to the present application.

[0027] Figure 7 A schematic diagram of a filter circuit in the present application.

[0028] Reference signs are: 1, flexible body; 11, first encapsulation layer; 111, PDMS substrate; 112, bionic scale; 12, second encapsulation layer; 13, electrode layer; 14, flexible PI layer; 2, cluster unit; 3, elastic member. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] Embodiment 1 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 flexible sensors in high-precision medical diagnosis. Although some existing technologies use "fish scale" bionic structure 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. Such arrangement can improve the detection accuracy of the sensor to small pressure, but it is easy to cause the skin to form a depression under long-term wearing, which greatly reduces the wearing comfort. To solve the above problems, the embodiment is invented.

[0031] Please refer to Figures 1 to 7 As shown in the figure, an embodiment of the present 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 two flexible PI layers 14 are respectively located on the upper and lower sides of the electrode layer 13, and the first encapsulation layer 11 and the second encapsulation layer 12 are respectively bonded to the corresponding flexible PI layers 14. A metal film for conducting electricity is evaporated on the flexible PI layer 14.

[0032] Please refer to Figure 6 and Figure 7 As shown in the figure, the electrode layer 13 is provided with a signal acquisition circuit. The signal acquisition circuit comprises 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 acquisition. 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.

[0033] The flexible main body 1 is externally connected with a data storage conversion device, which 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, the ADC conversion module converts the signal into a digital signal and sends the digital signal to the single-chip microcomputer, the single-chip microcomputer processes the digital piezoelectric signal, and the processed data is transmitted to an APP or an upper computer through the Bluetooth module.

[0034] Referring to Figures 2 to 4 As shown in the figure, the first encapsulation layer 11 comprises 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 comprises a plurality of bionic scales 112.

[0035] Referring to Figure 3 As shown in the figure, the plurality of bionic scales 112 are distributed in an array or staggered array.

[0036] Referring to Figure 4 As shown in the figure, the bionic scale 112 is a semi-ellipsoidal body, the cross-sectional width of which changes continuously along the height direction, and each bionic scale 112 has an arc-shaped outer surface without sharp protrusions, which is used to contact the flexible PI layer 14.

[0037] 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 encapsulation layer 11 and the second encapsulation layer 12 in the embodiment can contact the skin, and in the conventional detection, the detection of the micro pressure is not required, for example, the flexible main body 1 is attached to the joint for pressure detection, and in the embodiment, the detection mode of the sensor is described by taking the contact between the first encapsulation layer 11 and the skin of the neck as an example.

[0038] In the embodiment, the electrode layer 13 is a silver-plated PVDF film, and the preparation method thereof comprises the following steps: cutting the silver-plated PVDF film into a specified size, in the embodiment, the size of the silver-plated PVDF film is 11mm*11mm, then cleaning with anhydrous ethanol to remove burrs around to prevent short circuit, then cleaning with ultrapure water to remove the residual anhydrous ethanol on the surface, then blowing dry with a nitrogen gun after cleaning, and then checking whether the film is short-circuited by a multimeter.

[0039] 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 in a mass ratio of 10:1, the mixture is stirred until it turns white and the bubbles are dense (indicating that the mixture is uniform and forms a prepolymer), then the prepolymer is placed in a vacuum dryer to remove bubbles for 10 minutes; after the bubbles completely disappear, the prepolymer is injected into a 3D printing mold with a bionic scale 112 structure, and then placed in an oven for heating and curing at 60°C for 6 hours.

[0040] 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 made separately, and then the scale microstructure and the PDMS substrate 111 are bonded and fixed.

[0041] In addition, the flexible PI layer 14 in this embodiment is a copper-plated PI, and its preparation method comprises the following steps: using an evaporation machine to plate a 150 nm copper film on a flexible PI substrate, cutting to a specified size, and then washing with anhydrous ethanol and ultrapure water to remove impurities to obtain the flexible PI layer 14.

[0042] The preparation method of the flexible main body 1 is supplemented as follows: after two pieces of flexible PI layer 14 are bonded to the front and back of the electrode layer 13 by using conductive silver glue, the flexible PI layer 14 is placed in an oven at a temperature of 40°C for heating for 3 min to excite the conductivity of the conductive silver glue, and then the conductive silver glue is cured 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 the gap between the first encapsulation layer 11 and the adjacent flexible PI layer 14 is a normal phenomenon due to the scale microstructure, and the gap does not need to be treated.

[0043] 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 is transmitted to each bionic scale 112 through the flat PDMS substrate 111. Since the scale itself is similar to a cantilever beam structure, the force is conducted along the inclined surface of the scale and finally forms a high stress concentration at the tip of the scale.

[0044] That is, the inclined structure of the scale actually plays a role similar to a "lever", which can amplify the small pressure on 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 to the small pressure.

[0045] In summary, through the scale microstructure, the flexible PI layer 14, and the first encapsulation layer 11, etc., the PDMS substrate 111 of the first encapsulation layer 11 is in contact with the skin 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 the small pressure, and the scale microstructure is "wrapped" inside the PDMS substrate 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.

[0046] Embodiment 2 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 at low pressure due to stress concentration effect (such as fish scale tip contact), but in the case of high pressure (>20kPa), for example, 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 "surface contact" during the deformation process, resulting in saturation of the contact area, and then the problem of sudden drop in sensitivity or even signal distortion occurs. Further improvements are made on the basis of the above embodiments.

[0047] Please refer to Figure 4 As shown in the figure, the first encapsulation layer 11 also includes 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.

[0048] 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.

[0049] The material of the elastic member 3 is consistent with the PDMS base 111 of the first encapsulation layer 11.

[0050] 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.

[0051] 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.

[0052] On the basis of the above embodiments, when the flexible main body 1 is worn on the detection part during use, taking the neck as an example, when the wearer's head is laterally deviated and causes the flexible main body 1 to stretch, because the elastic modulus of the elastic member 3 is less than that of the scale microstructure, the elastic stress is preferentially released through the extension or bending of the elastic member 3, while the scale unit itself and its contact points with the PI layer remain relatively stable.

[0053] 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 sweating increases, and the sensor is stretched due to the limb activity, the active gap will be enlarged, forming a wider sweat discharge channel.

[0054] In summary, through the setting of the elastic member 3, the movable gap, and the cluster unit 2, the elastic member 3 becomes the main component for absorbing macroscopic 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 3, while the bionic scales 112 and the contact tips of the flexible PI layer 14 remain relatively stable. The morphology and inclination angle of the bionic scales 112 do not change due to overall stretching, and the stress concentration effect of the bionic scales 112 for micro-pressure is always at the optimal working point. Moreover, the movable 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.

[0055] Embodiment 3 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 may directly enter the scale microstructure through the movable gap. When the wearer exercises a lot or wears for a long time, the amount of sweat accumulation is large, and the metal in the flexible PI layer 14 will be eroded by sweat. Lightly, the detection accuracy decreases, and heavily, the sensor fails. In order to avoid or improve the above problems, this embodiment is proposed.

[0056] 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.

[0057] 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.

[0058] In summary, through the setting of the hydrophobic coating and the flexible waterproof layer, not only the sweat discharge function of the first packaging layer 11 is retained, but also the erosion of sweat to the flexible PI layer 14 is avoided, and the influence of the sweat of the wearer on the flexible PI layer 14 is improved or even avoided.

[0059] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can make equivalent replacements or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by 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 multiple biomimetic scales.

2. The high-performance flexible wearable pressure acquisition device combining a biomimetic scale structure with skin conformability as described in claim 1, characterized in that, The biomimetic scales are distributed in an array or an alternating 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 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.

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 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.

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 1, 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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