Asymmetric magnetic microcolumn array and respiration monitoring system based on same

Abstract

The invention discloses an asymmetric magnetic micro-column array and a respiration monitoring system based on the asymmetric magnetic micro-column array. The asymmetric magnetic micro-column array comprises a flexible substrate; a magnetic micro-column array is arranged on the flexible substrate; the magnetic micro-column array comprises a plurality of magnetic micro-columns which are vertically arranged on the flexible substrate; the magnetic micro-column comprises a magnetic section and a flexible section; the flexible section is fixed on the surface of the flexible substrate; the magnetic section is of a cuboid structure and has different lengths and widths; the flexible section is of a cylinder structure; the flexible section is prepared by curing a prepolymer, and the magnetic section is prepared by curing a mixture of magnetic particles and the prepolymer. According to the invention, through a spatial difference response mechanism, airflow disturbances in different directions generate difference signals in the array, and environmental noise is suppressed. The respiration monitoring system based on the asymmetric magnetic microcolumn array is high in sensitivity, good in stability, wide in detection range, good in fatigue resistance and capable of achieving long-time detection, and a new thought is provided for home diagnosis and monitoring of the sleep apnea hypopnea syndrome.

Description

Technical Field

[0001] The present invention belongs to the technical field of respiratory monitoring sensors, and relates to an asymmetric magnetic microcolumn array and a respiratory monitoring system based on the same. Background Art

[0002] Respiration is an important parameter in human health monitoring and is necessary for long-term monitoring, which is of great significance for characterizing human health. For some potential patients, long-term respiratory monitoring can provide certain references for the diagnosis of some diseases, such as: chronic obstructive pulmonary disease, asthma, sleep apnea hypopnea syndrome. Sleep Apnea Hypopnea Syndrome (SAHS) has attracted more and more attention due to its high incidence rate and serious impact on quality of life. SAHS not only affects sleep quality, but may cause multi-organ and multi-system diseases such as cardiovascular and cerebrovascular diseases and endocrine metabolism without reasonable treatment. In severe cases, it may even increase the risk of sudden death.

[0003] The "gold standard" for the diagnosis of sleep apnea syndrome is polysomnography (PSG), which needs to be carried out in a specific "sleep room" in the hospital. The subject needs to wear up to more than ten kinds of sensors and complete the whole-night sleep monitoring while basically maintaining the sleeping position unchanged. In addition, the current solutions for detecting human respiration also include contact type and non-contact type. Among them, the non-contact type includes using radar to judge the human respiratory state and judging the human respiratory state by collecting the acoustic signal during human respiration. The advantages of these two methods are that they hardly interfere with the sleep of the subject, but they both have problems such as being easily affected by the environment and low accuracy of detection results. The contact type mainly reflects the respiratory condition of the subject by detecting the changes in temperature and humidity during the breathing process of the subject, but this process lacks in both response time and anti-environmental interference.

[0004] In recent years, magnetic signals have been increasingly applied in the field of detecting minute deformations and forces due to their high sensitivity and directivity characteristics. By combining magnetic materials with traditional materials and designing different structures, researchers have achieved sensitivities that are difficult to reach with traditional detection methods. In addition, magnetic signals can also be used to identify the direction of stress, which further reduces the complexity of sensor design and the difficulty of data processing. Among different driving methods for triggering mechanical deformation / movement, magnetic field driving is widely used due to its advantages of instantaneous response, simple non-destructive control, and low cost. For magnetoresponsive micro-nano structures, when slender magnetic micro-columns are stimulated by external forces, they will undergo mechanical deformation or movement, thereby forming a corresponding relationship with external stimuli. Single-micro-column sensors have obvious advantages in detecting extremely minute airflows, but they are also vulnerable to environmental interference, require high requirements for backend detection equipment, and have a relatively high difficulty in data processing. The design of an array can increase the detection range and improve the anti-interference ability of the sensor. Symmetrical micro-column arrays have the same response sensitivity to vertical and parallel winds, so they are prone to interference from airflows in another direction during the detection of one direction. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides an asymmetric magnetic micro-column array and a respiration monitoring system based on the same, thereby solving the technical problems that single-micro-column sensors in the prior art are vulnerable to environmental interference, have high requirements for backend detection and data processing, and symmetrical micro-column arrays are prone to interference from multi-directional airflows.

[0006] The present invention is realized through the following technical solutions:

[0007] An asymmetric magnetic micro-column array includes a flexible substrate; a magnetic micro-column array is provided on the flexible substrate; the magnetic micro-column array includes a plurality of magnetic micro-columns vertically arranged on the flexible substrate;

[0008] The magnetic micro-column includes a connected magnetic section and a flexible section; the flexible section is fixed on the surface of the flexible substrate;

[0009] The magnetic section is in a cuboid structure, and the length and width of the magnetic section are different; the flexible section is in a cylinder structure;

[0010] The flexible section is prepared by curing a prepolymer, and the magnetic section is prepared by curing a mixture of magnetic particles and a prepolymer.

[0011] Preferably, the magnetic micro-columns are arranged in an array on the flexible substrate; the number of magnetic micro-columns is 4 to 11; and the distance between any two adjacent magnetic micro-columns is 0.6 to 1.2 mm.

[0012] Preferably, the number of magnetic micro-columns on the flexible substrate is 8, and they are arranged in three rows. The number of magnetic micro-columns in each row is 3, 2, and 3 respectively. At the same time, the distance between any two adjacent magnetic micro-columns is 1.0 mm.

[0013] Preferably, the height ratio of the magnetic section to the flexible section is (1 - 3):(1 - 3).

[0014] Preferably, the height ratio of the magnetic section to the flexible section is 1:1.

[0015] Preferably, the weight ratio of the magnetic section to the flexible section is (1.5 - 2.5):1.

[0016] Preferably, the weight ratio of the magnetic section to the flexible section is 2.0:1.

[0017] Preferably, the preparation of the magnetic section is as follows: Mix magnetic particles, prepolymer, and curing agent evenly to obtain a magnetic mixture, and pour the magnetic mixture into a metal array mold for curing; the preparation of the flexible section is as follows: Mix prepolymer and curing agent evenly to obtain a flexible mixture, pour the flexible mixture into a paraffin array mold, and connect the paraffin array mold with the metal array mold so that the flexible mixture is connected to the cured magnetic section, and then cure the flexible mixture to obtain the flexible section; then magnetize the magnetic section to obtain the magnetic section.

[0018] Preferably, the magnetic particles account for 62.5% of the total mass of the magnetic particles, prepolymer, and curing agent; when magnetizing, the magnetic field strength of the uniform magnetic field is 1 - 2 T.

[0019] A respiration monitoring system based on an asymmetric magnetic micro-column array, comprising an asymmetric magnetic micro-column array according to any one of claims 1 - 9.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The present invention discloses an asymmetric magnetic microcolumn array. First, the magnetic segment adopts a cuboid structure. By mixing magnetic particles with a prepolymer and curing them, a rigid magnetic response core is formed. The length and width of the magnetic segment are different. When it is used as a sensor, when the airflow acts on the microcolumn from different directions, the difference in length and width results in different force-receiving areas of the magnetic segment on the windward side and the side, generating a differential magnetic-force coupling response and forming distinguishable electrical signal patterns, effectively realizing the differentiation of multi-directional airflow disturbances. That is, by having different structures on the windward side and perpendicular to the windward side, through the spatial difference response mechanism, airflow disturbances in different directions generate different signals in the array. This design effectively suppresses noise in the environment and improves the accuracy of testing. Additionally, the flexible segment adopts a cylindrical prepolymer curing structure to absorb environmental vibrations and airflow disturbances through elastic deformation. Secondly, the magnetic particles in the magnetic segment are arranged along the magnetic field direction to form anisotropic magnetic domains, enhancing the directional response sensitivity to the target magnetic field.

[0022] Furthermore, the magnetic microcolumns are arranged in an array on the flexible substrate; and the number of magnetic microcolumns is 4 to 11; and the distance between any two adjacent magnetic microcolumns is 0.6 to 1.2 mm. First, the minimum number of magnetic microcolumns is 4 to ensure that the array can construct the smallest detectable vector field gradient, and the upper limit is 11 to avoid the magnetic domain coupling effect between microcolumns. When the number exceeds 11, the leakage magnetic field of adjacent microcolumns will cause non-linear interference, resulting in a decrease in sensitivity. Additionally, for the distance between any two adjacent magnetic microcolumns, if it is less than 0.6 mm, the wake vortex of the upstream microcolumn will directly affect the response of the downstream microcolumn, resulting in signal distortion. When the distance between any two adjacent magnetic microcolumns is 0.6 to 1.2 mm, it can effectively increase the response intensity of a single magnetic microcolumn to the airflow, reduce the interference between adjacent magnetic microcolumns, and improve the detection sensitivity of the array to the airflow.

[0023] Furthermore, the number of magnetic microcolumns on the flexible substrate is 8, and they are arranged in three rows. The number of magnetic microcolumns in each row is 3, 2, and 3 respectively. At the same time, the distance between any two adjacent magnetic microcolumns is 1.0 mm. Here, the arrangement of the magnetic microcolumns is an asymmetric topological structure, forming a sensitive area similar to a "dumbbell shape". The edge microcolumns (the 1st and 3rd in each row) and the central microcolumn (the 2nd in each row) constitute a natural differential amplification effect, enhancing the direction sensitivity.

[0024] Furthermore, the height ratio of the magnetic segment to the flexible segment is (1 to 3):(1 to 3). When the height ratio is close, the difference in bending stiffness between the magnetic segment and the flexible segment is minimized, avoiding stress concentration at the interface and improving the fatigue life of the magnetic microcolumn. Additionally, when the height difference between the magnetic segment and the flexible segment is small during bending deformation, the position of the neutral axis is fixed, avoiding interface delamination caused by asynchronous deformation between the magnetic segment and the flexible segment.

[0025] Further, the height ratio of the magnetic segment to the flexible segment is 1:1, which can achieve the optimal matching effect between the bending stiffness and the residual magnetic field strength of the magnetic micro-columns, and the response sensitivity to the air flow is the highest.

[0026] Further, the weight ratio of the magnetic segment to the flexible segment is (1.5 - 2.5):1. When the weight ratio increases, the mass proportion of the magnetic segment increases, causing the overall resonance frequency of the device to shift to a lower frequency, making it more suitable for detecting low-frequency mechanical vibrations and applicable to the detection during the breathing process.

[0027] Further, the weight ratio of the magnetic segment to the flexible segment is 2.0:1, which can achieve the optimal combination effect between the residual magnetic field strength and the center-of-gravity distribution of the magnetic micro-columns, and the response sensitivity to the air flow is the highest.

[0028] Further, the magnetic particles account for 62.5% of the total mass of the magnetic particles, prepolymer, and curing agent; when magnetizing, the magnetic field strength of the uniform magnetic field is 1 - 2T. First, 62.5% of the mass fraction is close to the maximum packing density of the magnetic particles, forming a continuous magnetic conduction network. Additionally, the magnetic field strength of the uniform magnetic field being 1 - 2T can cause the magnetic domains of the magnetic particles to be completely arranged along the magnetic field direction, effectively improving the detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0030] Figure 1 It is the process flow chart for the preparation of the asymmetric magnetic micro-column array of the present invention;

[0031] Figure 2 It is the structural schematic diagram of a single magnetic micro-column in the asymmetric magnetic micro-column array of the present invention;

[0032] Figure 3 It is the structural schematic diagram of the asymmetric magnetic micro-column array prepared in Example 5 of the present invention, where (a) is the front view, (b) is the left view, (c) is the top view, and (d) is the three-dimensional view;

[0033] Figure 4 It is the schematic diagram of the asymmetric magnetic micro-column array prepared in Example 5 of the present invention under air flows in different directions;

[0034] Figure 5 It is the variation of the magnetic field strength under different air flow velocities when the flexible end is a cylinder and the magnetic segments are cylindrical and cuboid respectively;

[0035] Figure 6 The variation of the magnetic field intensity of different asymmetric magnetic micro-column arrays prepared in the present invention under different gas flow rates, where (a) shows different magnetic micro-column spacings D of the asymmetric magnetic micro-column array, and (b) shows different arrangement modes of the asymmetric magnetic micro-column array;

[0036] Figure 7 The variation of the magnetic field intensity of the asymmetric magnetic micro-column arrays prepared in Examples 5, 7, and 8 of the present invention under different gas flow rates, that is, the relationship between the gas flow rate and the change of the magnetic field intensity when the mass ratio of the magnetic segment to the flexible segment of a single magnetic micro-column in the asymmetric magnetic micro-column array is different;

[0037] Figure 8 The variation of the magnetic field intensity of the asymmetric magnetic micro-column arrays prepared in Examples 5, 9, and 10 of the present invention under different gas flow rates, that is, the relationship between the gas flow rate and the change of the magnetic field intensity when the heights of the magnetic segment and the flexible segment of a single magnetic micro-column in the asymmetric magnetic micro-column array are different;

[0038] Figure 9 The variation of the magnetic field intensity of the asymmetric magnetic micro-column arrays prepared in Examples 4, 5, and 6 of the present invention under different gas flow rates, that is, the relationship between the gas flow rate and the change of the magnetic field intensity when the arrangement mode of the asymmetric magnetic micro-column array is different;

[0039] Figure 10 The conceptual diagram of the asymmetric magnetic micro-column array respiration monitoring system in the present invention;

[0040] Figure 11 The circuit board design diagram of the asymmetric magnetic micro-column array respiration monitoring system in the present invention;

[0041] Figure 12 The performance test results of the asymmetric magnetic micro-column array respiration monitoring sensor assembled with the asymmetric magnetic micro-column array prepared in Example 5, where (a) is the working curve diagram; (b) is the strong and weak signal alternating test diagram; (c) is the response time - recovery time test diagram;

[0042] Figure 13 The output signal diagram of the asymmetric magnetic micro-column array respiration monitoring sensor assembled with the asymmetric magnetic micro-column array prepared in Example 5 under different breathing conditions.

[0043] Among them, 1 is the magnetic segment, 2 is the flexible segment, and 3 is the flexible substrate. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the detailed description of the embodiments of the present invention provided in the drawings below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0046] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0047] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is usually placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.

[0048] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0049] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "connected" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The following further describes the present invention in detail with reference to the accompanying drawings:

[0051] 1. The following Examples 1 to 10 provide a preparation method of an asymmetric magnetic microcolumn array, specifically as follows:

[0052] Example 1

[0053] As shown in Figure 1 (a) - (f), a preparation method of an asymmetric magnetic microcolumn array includes the following steps:

[0054] S1: Weigh 2 g of Fe3O4 (i.e., magnetic particles), 1 g of Ecoflex, and 0.2 g of curing agent, stir them evenly to obtain a magnetic mixture. Pour the magnetic mixture into a metal array mold, and place the metal array mold containing the magnetic mixture in a vacuum chamber for 10 min to remove the air in the magnetic mixture. Then put the metal array mold containing the magnetic mixture into an oven and cure it at 60 °C for 3 h to form a metal array mold with a cured magnetic segment. The mold holes of the metal array mold are in a cuboid structure;

[0055] Among them, Ecoflex is a platinum-catalyzed addition-type liquid silicone rubber, mainly composed of two-component silicone rubber (Part A is the base rubber, and Part B is the curing agent), and it cures through a platinum-catalyzed addition reaction. During this process, Fe3O4 is evenly dispersed in the silicone rubber matrix to form a magnetic composite material, and a stable three-dimensional network is formed through the cross-linking reaction of the curing agent to fix the position of Fe3O4.

[0056] The curing agent is Dow Corning DC184, n3300, and preferably Dow Corning DC184.

[0057] S2: Weigh 10 g of Ecoflex and 0.2 g of curing agent, stir them evenly to obtain a flexible mixture, and pour the flexible mixture into a paraffin array mold. The paraffin array mold is combined and fixed with the above-mentioned metal array mold containing the magnetic segment. At the same time, the flexible mixture in step S2 is in contact with the above-mentioned magnetic segment. Then place the whole composed of the paraffin array mold containing the flexible mixture and the metal array mold with the cured magnetic segment in a vacuum chamber for 10 min to remove the air in the flexible mixture, and then put it into a 60 °C oven to cure for 1 h. The flexible mixture in the paraffin array mold cures to form a flexible segment. Here, the flexible segment and the magnetic segment form an asymmetric magnetic microcolumn array. The paraffin array mold is sacrificed by heating, and the obtained asymmetric magnetic microcolumn array is removed from the metal array mold. The mold holes of the paraffin array mold are in a cylindrical structure;

[0058] S3: Use a uniform magnetic field along the length direction of the magnetic microcolumn, that is, Figure 1 the vertical direction of the T direction in

[0059] The structures of the metal array mold and the paraffin array mold selected in this implementation are the same. In this embodiment, the arrangement of the mold holes in the metal array mold and the paraffin array mold is of the 1-2-1 type. The three-dimensional structure of the magnetic micro-columns obtained by using one corresponding mold hole in the metal array mold and the paraffin array mold is as Figure 2 shown, and the ratio of the mass (w1) of the magnetic segment 1 obtained by the metal array mold to the mass (w2) of the flexible segment 2 obtained by the paraffin array mold is 2.5:1, that is Figure 1 in Figure 1 , w1:w2 = 2.5:1. The ratio of the height (h1) of the magnetic segment 1 obtained by the metal array mold to the height (h2) of the flexible segment 2 obtained by the paraffin array mold is 3:1, that is Figure 1 in Figure 1 , h1:h2 = 3:1. The distance between any two adjacent magnetic micro-columns is equal, all being 0.6 mm, that is Figure 3 the D value in Figure 3 is 0.6 mm, that is, three magnetic micro-columns with equal distances between each other form an equilateral triangle. That is, the arrangement of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 1-2-1 type, w1:w2 = 2.5:1, h1:h2 = 3:1, D = 0.6 mm.

[0060] The asymmetric magnetic micro-column array in the present invention has two aspects of meaning: First, the upper and lower parts of a single magnetic micro-column have an asymmetric structure, that is, the structures of the magnetic segment obtained by the paraffin array mold and the flexible segment obtained by the metal array mold are different. The magnetic segment is a cuboid structure, and the flexible segment is an arc structure, which is an upper and lower asymmetric structure; Second, the structure of the windward surface of the magnetic segment 1 is different from the structure perpendicular to the windward surface.

[0061] Embodiment 2

[0062] The difference between this embodiment and Embodiment 1 is:

[0063] A method for preparing an asymmetric magnetic micro-column array includes the following steps:

[0064] S1: The magnetic mixture includes 10 g of Fe3O4 and 20 g of TPU, and is cured for 1 h; where TPU is thermoplastic polyurethane, and is used in combination with the magnetic particles Fe3O4 as a flexible polymer matrix.

[0065] S2: The flexible mixture includes 1 g of Ecoflex and 1 g of curing agent;

[0066] S3: Use a uniform magnetic field along the length direction of the magnetic micro-column, that is Figure 1 the T direction in Figure 1 , to magnetize and obtain an asymmetric magnetic micro-column array, where the magnetic field strength of the uniform magnetic field is 2 T.

[0067] In this embodiment, the arrangement pattern of the die holes of the metal array mold and the paraffin array mold is of the 2-1-2 type, w1:w2 = 2.0:1, h1:h2 = 1:3, and D = 1.4 mm.

[0068] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 2-1-2 type, w1:w2 = 2.0:1, h1:h2 = 1:3, and D = 1.4 mm.

[0069] Example 3

[0070] The difference between this embodiment and Example 1 is as follows:

[0071] A preparation method of an asymmetric magnetic micro-column array includes the following steps:

[0072] S1: The magnetic mixture includes 2 g of NdFeB, 1 g of PDMS, and 0.2 g of curing agent, and is cured for 1 h; wherein, PDMS is polydimethylsiloxane;

[0073] S2: The flexible mixture includes 1 g of PDMS and 0.05 g of curing agent, and the curing time is 3 h;

[0074] S3: Use a uniform magnetic field along the length direction of the magnetic micro-columns, that is, Figure 1 the T direction in, to magnetize and obtain an asymmetric magnetic micro-column array, wherein the magnetic field strength of the uniform magnetic field is 1.6 T.

[0075] In this embodiment, the arrangement pattern of the die holes of the metal array mold and the paraffin array mold is of the 2-1-2 type, w1:w2 = 1.5:1, h1:h2 = 3:1, and D = 1.0 mm.

[0076] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 2-1-2 type, w1:w2 = 1.5:1, h1:h2 = 3:1, and D = 1.0 mm.

[0077] Example 4

[0078] The difference between this embodiment and Example 3 is that: the arrangement pattern of the die holes of the metal array mold and the paraffin array mold is of the 3-3-3 type, w1:w2 = 2.0:1, h1:h2 = 1:1.

[0079] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 3-3-3 type, w1:w2 = 2.0:1, h1:h2 = 1:1, and D = 1.0 mm.

[0080] Example 5

[0081] The difference between this embodiment and Embodiment 4 is that the arrangement pattern of the die holes of the metal array mold and the paraffin array mold is of the 3-2-3 type.

[0082] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 3-2-3 type, w1:w2 = 2.0:1, h1:h2 = 1:1, D = 1.0 mm. The schematic diagram of the arrangement pattern of the asymmetric magnetic micro-column array in this embodiment is shown in Figure 3 shown.

[0083] Embodiment 6

[0084] The difference between this embodiment and Embodiment 4 is that the arrangement pattern of the die holes of the metal array mold and the paraffin array mold is of the 2-3-2 type.

[0085] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 2-3-2 type, w1:w2 = 2.0:1, h1:h2 = 1:1, D = 1.0 mm.

[0086] Embodiment 7

[0087] The difference between this embodiment and Embodiment 5 is that w1:w2 = 2.5:1;

[0088] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 3-2-3 type, w1:w2 = 2.5:1, h1:h2 = 1:1, D = 1.0 mm.

[0089] Embodiment 8

[0090] The difference between this embodiment and Embodiment 5 is that w1:w2 = 1.5:1;

[0091] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 3-2-3 type, w1:w2 = 1.5:1, h1:h2 = 1:1, D = 1.0 mm.

[0092] Embodiment 9

[0093] The difference between this embodiment and Embodiment 5 is that h1:h2 = 3:1;

[0094] That is, the arrangement pattern of the finally obtained asymmetric magnetic micro-column array in this embodiment is of the 3-2-3 type, w1:w2 = 1.5:1, h1:h2 = 3:1, D = 1.0 mm.

[0095] Embodiment 10

[0096] The difference between this embodiment and Embodiment 5 is that h1:h2 = 1:3;

[0097] That is, the arrangement of the finally obtained asymmetric magnetic microcolumn array in this embodiment is of the 3-2-3 type, w1:w2 = 1.5:1, h1:h2 = 1:3, and D = 1.0 mm.

[0098] For all the above embodiments, the corresponding relationship between the flow rate and the magnetic change amount was measured after preparation, and the optimal material size scheme was selected.

[0099] When the asymmetric magnetic microcolumn array prepared in the present invention is subjected to mechanical forces in different reverse directions, such as Figure 4 the vertical wind and the parallel wind in, since the acting area of the vertical wind on the magnetic segment is different from the acting area of the parallel wind on the magnetic segment, the asymmetric magnetic microcolumn array can effectively monitor airflows in different directions.

[0100] The relevant parameters of the asymmetric magnetic microcolumn arrays prepared in the above Embodiments 1 to 10 are shown in Table 1.

[0101] Table 1 Relevant parameters of the asymmetric magnetic microcolumn arrays prepared in Embodiments 1 to 10

[0102] Sample Arrangement mode <![CDATA[w1:w2]]> <![CDATA[h1:h2]]> D / mm Example 1 1 - 2 - 1 type 2.5:1 3:1 0.6 Example 2 2 - 1 - 2 type 2.0:1 1:3 1.4 Example 3 2 - 1 - 2 type 1.5:1 3:1 1.0 Example 4 3 - 3 - 3 type 2.0:1 1:1 1.0 Example 5 3 - 2 - 3 type 2.0:1 1:1 1.0 Example 6 2 - 3 - 2 type 2.0:1 1:1 1.0 Example 7 3 - 2 - 3 type 2.5:1 1:1 1.0 Example 8 3 - 2 - 3 type 1.5:1 1:1 1.0 Example 9 3 - 2 - 3 type 2.0:1 3:1 1.0 Example 10 3 - 2 - 3 type 2.0:1 1:3 1.0

[0103] The structure of an asymmetric magnetic microcolumn array prepared by the present invention is as shown in Figure 3 and includes a flexible substrate 3; a magnetic microcolumn array is provided on the flexible substrate 3; the magnetic microcolumn array includes a plurality of magnetic microcolumns vertically arranged on the flexible substrate 3; the magnetic microcolumns include a connected magnetic segment 1 and a flexible segment 2; the flexible segment 2 is fixed on the surface of the flexible substrate 3; the magnetic segment 1 is in a cuboid structure, and the flexible segment 2 is in a cylinder structure; the structure of the windward surface of the magnetic segment 1 is different from the structure perpendicular to the windward surface; the flexible segment 2 is prepared by curing a prepolymer, and the magnetic segment 1 is prepared by curing a mixture of magnetic particles and a prepolymer.

[0104] As can be seen from the above embodiments, the magnetic microcolumns are arranged in an array on the flexible substrate 3; and the number of magnetic microcolumns is 4 to 9; and the distance between any two adjacent magnetic microcolumns is 0.6 to 1.2 mm. Preferably, the number of magnetic microcolumns on the flexible substrate 3 is 8, and they are arranged in three rows, with the number of magnetic microcolumns in each row being 3, 2, and 3 respectively. At the same time, the distance between any two adjacent magnetic microcolumns is 1.0 mm.

[0105] The height ratio of the magnetic segment 1 to the flexible segment 2 is (1 to 3):(1 to 3). Preferably, the height ratio of the magnetic segment 1 to the flexible segment 2 is 1:1.

[0106] The weight ratio of the magnetic segment 1 to the flexible segment 2 is (1.5 to 2.5):1. Preferably, the weight ratio of the magnetic segment 1 to the flexible segment 2 is 2.0:1.

[0107] The height of the cuboid-shaped magnetic segment 1 is 0.5 - 2 mm, the length is 0.3 - 0.6 mm, and the width is 0.1 - 0.3 mm.

[0108] The radius of the cylindrical flexible segment 2 is 0.1 - 0.5 mm, and the height is 0.5 - 2 mm.

[0109] The magnetic particles are Fe3O4 or NdFeB, and the prepolymer Ecoflex can also be polydimethylsiloxane (PDMS) or thermoplastic polyurethane elastomer (TPU).

[0110] The arrangement of the magnetic micro-columns can be 1-2-1, 2-1-2, 2-2-2, 2-3-2, 3-2-3, 3-3-3, 3-4-3 or 4-3-4. That is, the arrays are all arranged in three rows, and the number of magnetic micro-columns in the three rows is different.

[0111] In addition, when preparing the asymmetric magnetic micro-column array, the curing time is 1 - 3 h, preferably 3 h.

[0112] Meanwhile, the present invention also discloses a simulation of a respiratory monitoring system based on the asymmetric magnetic micro-column array, that is, establishing a steady-state solid mechanics field model of the magnetic micro-column deforming under force, which is used to calculate that when an external force is applied to the magnetic micro-column, the magnetic micro-column will undergo corresponding deformation, and calculate the state of the magnetic micro-column when the system reaches a steady state. The formula is as follows:

[0113]

[0114] In the formula, is the deformation gradient, Fv is the body force, F is the deformation gradient tensor, I is the identity matrix, is the displacement gradient tensor.

[0115] Then establish a steady-state magnetic field model generated by the magnetic segment of the micro-column, which is used to calculate the magnetic field distribution state generated when the magnetic micro-column is in a certain state. The formula is as follows:

[0116]

[0117] J = σE + J e

[0118] In the formula, H is the magnetic field strength, J is the current density, B is the magnetic induction intensity, A is the magnetic vector potential, σ is the conductivity, E is the electric field strength, J e is the external current density.

[0119] Coupling the above two physical fields and performing a joint calculation can obtain the deformation of the magnetic micro-columns under the action of a certain force and the resulting change in the spatial magnetic field distribution state. By statistically analyzing the change in the magnetic field intensity at a fixed position, the response degree of the micro-column array to the force can be characterized, and then its sensitivity can be calculated.

[0120] II. Examples 11 - 12 below provide the preparation of an asymmetric magnetic micro-column array respiration monitoring sensor, specifically as follows:

[0121] Example 11

[0122] As Figures 10 to 11 shown, the asymmetric magnetic micro-column arrays prepared in Examples 1 - 10 of the present invention are respectively combined with Hall sensors, and then the sensing unit (i.e., the asymmetric magnetic micro-column array) is connected to the PCB board through a flexible flat cable. The microcontroller unit TLSR8251 on the PCB board can integrate Bluetooth and communicate with the Hall sensor through an integrated circuit bus.

[0123] In this example, the model of the Hall sensor used is ML90393. This Hall sensor detects the magnetic field intensity based on the Hall effect. The displacement of the micro-column array causes a change in the magnetic field distribution, and ML90393 outputs a voltage signal proportional to the magnetic field intensity. When the asymmetric magnetic micro-column array forms a mechanical deformation under the action of air flow, the mechanical deformation causes a change in the magnetic field distribution. ML90393 converts the magnetic field change into an electrical signal based on the Hall effect, and after being processed by the built-in amplifier filter and analog-to-digital converter, it is sent to the application program of the smartphone through the SoC via Bluetooth. The entire system is powered by a 3.7V lithium battery with a capacity of 600 mAh after being processed by a low-dropout linear regulator. The circuit system is fixed to a commercial eye mask to complete the preparation of the entire asymmetric magnetic micro-column array respiration monitoring sensor.

[0124] The PCB board here is a printed circuit board, which carries electronic components and provides electrical interconnection, integrating Hall sensors, microcontrollers, power modules, etc.

[0125] Example 12

[0126] The difference between this example and Example 11 is that the asymmetric magnetic micro-column array prepared in Example 5 is used, combined with a Hall sensor of model BMM150 and an nRF52840 microcontroller unit to assemble an asymmetric magnetic micro-column array respiration monitoring sensor.

[0127] III. The following examples provide the monitoring of actual human respiration signals using the asymmetric magnetic micro-column array respiration monitoring sensors prepared in Example 11 and Example 12, specifically as follows:

[0128] Example 13

[0129] An asymmetric magnetic micro-column array respiration monitoring sensor of Example 11 and Example 12, namely a wireless eye mask type respiration sensor, was worn on the eyes of a male subject. The sensing unit was fixed on the lip facing the nostrils, and then the device was connected to a smartphone application. The total monitoring duration was 35 minutes. During this period, the subject was instructed to perform breathing conditions such as hypoventilation, normal breathing, deep breathing, rapid breathing, and apnea. The corresponding data was collected and analyzed using the sensor to determine the above signals.

[0130] Figure 5 When the flexible end is a cylinder and the magnetic segments are a cylinder and a cuboid respectively, the magnetic field intensity changes under different air flow velocities. As can be seen from the figure, the structure with a cuboid magnetic segment has better anti-interference ability against parallel wind compared to the cylindrical structure.

[0131] Figure 6 The magnetic field intensity changes of the prepared different asymmetric magnetic micro-column arrays under different gas flow velocities. Among them, (a) shows different magnetic micro-column spacings D of the asymmetric magnetic micro-column array, and (b) shows different arrangement patterns of the asymmetric magnetic micro-column array. As can be seen from the figure, when the magnetic micro-column spacing D is 1 mm and the arrangement pattern of the asymmetric magnetic micro-column array is 3-2-3, it has outstanding sensitivity.

[0132] Figure 7 The magnetic field intensity changes of the asymmetric magnetic micro-column arrays prepared in Examples 5, 7, and 8 of the present invention under different gas flow velocities, that is, the relationship between the gas flow velocity and the magnetic field intensity change when the mass ratio of the magnetic segment to the flexible segment of a single magnetic micro-column in the asymmetric magnetic micro-column array is different. As can be seen from the figure, when the mass ratio of the magnetic segment to the flexible segment is 2:1, it has outstanding sensitivity.

[0133] Figure 8 The magnetic field intensity changes of the asymmetric magnetic micro-column arrays prepared in Examples 5, 9, and 10 of the present invention under different gas flow velocities, that is, the relationship between the gas flow velocity and the magnetic field intensity change when the heights of the magnetic segment and the flexible segment of a single magnetic micro-column in the asymmetric magnetic micro-column array are different. As can be seen from the figure, when the mass ratio of the magnetic segment to the flexible segment is 1:1, it has outstanding sensitivity.

[0134] Figure 9 The magnetic field intensity changes of the asymmetric magnetic micro-column arrays prepared in Examples 4, 5, and 6 of the present invention under different gas flow velocities, that is, the relationship between the gas flow velocity and the magnetic field intensity change when the arrangement pattern of the asymmetric magnetic micro-column array is different. As can be seen from the figure, when the arrangement pattern of the asymmetric magnetic micro-column array is 3-2-3, it has outstanding sensitivity.

[0135] Figure 12Performance test results of the asymmetric magnetic microcolumn array respiration monitoring sensor assembled using the asymmetric magnetic microcolumn array prepared in Example 5. Among them, (a) is the working curve graph; (b) is the strong and weak signal alternating test graph; (c) is the response time - recovery time test graph. It can be seen from the figure that the asymmetric magnetic microcolumn array has good response fitting degree, strong and weak air flow alternating response ability, and fast response time.

[0136] Figure 13 Output signal graph of the asymmetric magnetic microcolumn array respiration monitoring sensor assembled using the asymmetric magnetic microcolumn array prepared in Example 5 under different respiration conditions. It can be seen from the figure that the asymmetric magnetic microcolumn array can detect different respiration conditions (such as hypoventilation, deep breathing, apnea, etc.). This respiration monitoring system can be worn on the eyes of the subject through an eye mask, the sensing unit is fixed on the lips opposite the nostrils, and then the device is connected to a smartphone application program to achieve continuous respiration monitoring during sleep.

[0137] Furthermore, through Figure 12 conventional performance detection of the sensor, it can be judged that the prepared asymmetric magnetic microcolumn array meets the clinical needs of the special disease of apnea. Through testing, the entire sensor has excellent sensitivity (1.02 μT / (L / min)), high stability (R 2 = 0.999), wide detection range (5 - 40 L·min -1 ), good fatigue resistance (500 - time fatigue test), long detection time (35 - minute actual human test), and many other excellent sensing performances. Subsequently, hypoventilation, normal breathing, deep breathing, rapid breathing, apnea and other breathing conditions were also successfully and sensitively detected in the 35 - minute human detection of actual subjects. Therefore, we can fully expect the clinical performance of this respiration monitoring system in the related monitoring of sleep apnea syndrome.

[0138] The present invention discloses a respiration monitoring system based on an asymmetric magnetic microcolumn array, belonging to the field of respiration monitoring sensors. By combining simulation and actual experimental operations, the present invention develops a home sleep respiration monitoring system based on a magnetic microcolumn array (MMA) and uses it for long-term sleep respiration monitoring, realizing the monitoring and recording of respiration conditions during sleep. The magnetic microcolumn array sensor can resist interference from temperature, humidity, and environmental wind in the environment and still exhibit good sensing stability after 500 cycles. The monitoring eye mask system based on a PCB circuit, equipped with a corresponding mobile application, constitutes a home sleep respiration monitoring system. Using this system, long-term and wireless monitoring of respiration during sleep can be completed, and the signal can be transmitted to a smartphone in real time via Bluetooth. This system has the characteristics of small size, high wearing comfort, and no impact on sleep, and can accurately record the respiration of volunteers in different sleep states. The present invention provides a new idea for the home diagnosis and monitoring of sleep apnea hypopnea syndrome and broadens the application scenario of magnetic signals in biomedicine.

[0139] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An asymmetric magnetic micro-column array, characterized in that It includes a flexible substrate (3); a magnetic micro-column array is provided on the flexible substrate (3); the magnetic micro-column array includes a plurality of magnetic micro-columns vertically arranged on the flexible substrate (3). The magnetic micro-column includes a connected magnetic segment (1) and a flexible segment (2); the flexible segment (2) is fixed on the surface of the flexible substrate (3). The magnetic segment (1) is in a cuboid structure, and the length and width of the magnetic segment (1) are different; the flexible segment (2) is in a cylinder structure. The flexible segment (2) is prepared by curing a prepolymer, and the magnetic segment (1) is prepared by curing a mixture of magnetic particles and a prepolymer.

2. The asymmetric magnetic micro-column array according to claim 1, wherein The magnetic micro-columns are arranged in an array on the flexible substrate (3); the number of magnetic micro-columns is 4 to 11; and the distance between any two adjacent magnetic micro-columns is 0.6 to 1.2 mm.

3. An asymmetric magnetic microcolumn array according to claim 1, characterized in that The number of magnetic micro-columns on the flexible substrate (3) is 8, and they are arranged in three rows, with the number of magnetic micro-columns in each row being 3, 2, and 3 respectively. At the same time, the distance between any two adjacent magnetic micro-columns is 1.0 mm.

4. An asymmetric magnetic microcolumn array according to claim 1, characterized in that, The height ratio of the magnetic segment (1) to the flexible segment (2) is (1 to 3):(1 to 3).

5. The asymmetric magnetic microcolumn array according to claim 1, characterized in that The height ratio of the magnetic segment (1) to the flexible segment (2) is 1:

1.

6. The asymmetric magnetic microcolumn array according to claim 1, characterized in that, The weight ratio of the magnetic segment (1) to the flexible segment (2) is (1.5 to 2.5):

1.

7. The asymmetric magnetic micro-column array according to claim 1, characterized in that The weight ratio of the magnetic segment (1) to the flexible segment (2) is 2.0:

1.

8. An asymmetric magnetic micro-column array according to claim 1, characterized in that, The preparation of the magnetic segment (1) is specifically as follows: magnetic particles, a prepolymer, and a curing agent are mixed evenly to obtain a magnetic mixture, and the magnetic mixture is poured into a metal array mold for curing; the preparation of the flexible segment (2) is specifically as follows: a prepolymer and a curing agent are mixed evenly to obtain a flexible mixture, the flexible mixture is poured into a paraffin array mold, and the paraffin array mold is connected to the metal array mold so that the flexible mixture is connected to the cured magnetic segment, and then the flexible mixture is cured to obtain the flexible segment; then the magnetic segment is magnetized to obtain the magnetic segment.

9. The asymmetric magnetic microcolumn array according to claim 1, characterized in that, The magnetic particles account for 62.5% of the total mass of the magnetic particles, the prepolymer, and the curing agent; when magnetizing, the magnetic field strength of the uniform magnetic field is 1 to 2 T.

10. A respiration monitoring system based on an asymmetric magnetic microcolumn array, characterized in that, It includes an asymmetric magnetic micro-column array according to any one of claims 1 to 9.

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