Portable mask for respiration monitoring and preparation method and application thereof

Abstract

The invention belongs to the technical field of thermoelectric devices, and relates to a portable mask for respiration monitoring and a preparation method and application thereof.The mask is provided with a flexible thermoelectric device, the flexible thermoelectric device comprises a packaging body and a thermoelectric unit array which are sequentially arranged from outside to inside, and the thermoelectric unit array comprises a plurality of thermoelectric units arranged in series; the thermoelectric unit comprises an n-type thermoelectric arm, a p-type thermoelectric arm and an electrode, the n-type thermoelectric arm and the p-type thermoelectric arm are connected through the electrode to form a transverse / longitudinal pi-type thermoelectric unit, the longitudinal pi-type thermoelectric unit and the transverse pi-type thermoelectric unit are alternately connected in series to form a thermoelectric unit array, and the thermoelectric unit array is packaged in a packaging body to obtain the flexible thermoelectric device. The flexible thermoelectric device is adhered to the interior of the commercial mask, and the portable mask for respiration monitoring is obtained. The mask converts temperature difference signals at the two ends of the device into electric signals through the Seebeck effect. Compared with the prior art, the mask is comfortable to wear and simple in structure, and real-time breathing monitoring under self power supply can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermoelectric devices, and in particular relates to a portable mask for respiratory monitoring, a preparation method thereof and an application thereof. Background Art

[0002] The current prevalence of Internet of Things technology has increased the demand for wearable electronic products that can achieve real-time sensing, especially for all-weather monitoring of human health. Wearable sensing technology can extract physiological parameters related to health status in real time and non-invasively, greatly expanding the way of personalized health monitoring. Currently, wearable sensors used to measure human physiological signals include multifunctional electronic skin, electrocardiogram sensors, glucose sensors, etc. Breathing, as an indispensable spontaneous behavior of human beings, is not only an important mechanism to maintain life by ensuring the exchange of oxygen and carbon dioxide, but also an important feature for assessing individual health or disease progression. This is mainly because the breathing process involves the heart, lungs, blood vessels and red blood cells throughout the body. Any problem with any of these factors may seriously affect the frequency of breathing. By monitoring the breathing frequency, some potential disease risks can be evaluated and warned.

[0003] At present, traditional clinical respiratory monitoring systems typically include invasive methods such as endotracheal intubation through the nose and mild non-invasive methods such as breathing masks. However, due to the poor accessibility, bulky equipment, high cost, uncomfortable use experience and reliance on external power sources, these methods are limited in their widespread adoption in home / personal healthcare and continuous monitoring. With the advancement of network technology and low-power electronic technology, wearable respiratory sensors for real-time respiratory monitoring have made great progress. Self-powered wearable sensors based on respiratory-related signals include triboelectric, piezoelectric, magnetoelectric, capacitive, etc. However, most sensors need to be tightly attached or tied to the chest, abdomen or throat for respiratory monitoring, which is not conducive to long-term wearing comfort and is often prone to motion artifacts; some sensors also contact the skin in the form of patches, which can easily cause skin discomfort and are not aesthetically pleasing. In addition, these sensors usually involve complex device structures and manufacturing processes, and inevitably have high costs, making them difficult to be popularized in the direction of personal use by the public. Therefore, there is an urgent need to develop a passive, comfortable, non-skin-touch, simple in structure, low-cost, and continuous real-time respiratory monitoring system.

[0004] Thermoelectric conversion technology is a technology based on the effect of thermoelectric materials to realize the direct conversion between thermal energy and electrical energy in a solid state. The energy conversion mainly relies on the thermoelectric effect. Thermoelectric effects mainly include Seebeck effect, Peltier effect and Thomson effect. Among them, the Seebeck effect is an important research direction. This effect can convert thermal energy into electrical energy in a direct way. Specifically, an electric potential difference will be generated at both ends of an object with a temperature difference. Thermoelectric generators (TEGs) convert electrical signals from heat flow, and they can be used as temperature sensors in various wearable areas. However, most existing TEGs are mainly bulky and rigid, with relatively large thickness, which hinders the accurate recording of dynamic human movement.

[0005] Patent application CN115224183A discloses a stretchable flexible thermoelectric device with wavy thermoelectric arms and a preparation method thereof. The device includes a thermoelectric unit, a flexible substrate, and a flexible package. The n-type and p-type thermoelectric arms in the thermoelectric unit are wavy, connected by electrodes to form a straight-line thermoelectric arm pair, and then connected to a heat-conducting column to form a T-shaped thermoelectric unit. The thermoelectric units are electrically connected in series to form a thermoelectric unit array and packaged in a flexible substrate. The flexible substrate is attached to the surface of the heat source for collecting heat. The horizontal thermoelectric arm array at the top of the thermoelectric unit array is packaged to form a flexible package. As the cold end of the thermoelectric device, a gap is left between the flexible substrate and the flexible package, which serves as a natural insulation layer to ensure that most of the heat flow direction perpendicular to the heat source is concentrated in the heat-conducting column. This device configuration combines the advantages of in-plane and out-of-plane thermoelectric devices. However, the flexible thermoelectric device disclosed in the patent application requires a large contact area with the heat source when collecting heat, and is not suitable for heat collection in a small range. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and to provide a portable mask for respiratory monitoring and its preparation method and application. Flexible thermoelectric devices are prepared using thermoelectric materials and integrated into 3D masks to monitor breathing. The prepared thermoelectric devices have excellent flexibility and can directly convert the temperature difference at both ends of the device into electrical signals without relying on an external power supply.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides a portable mask for respiratory monitoring. The portable mask is provided with a flexible thermoelectric device. The flexible thermoelectric device includes a packaging body and a thermoelectric unit array arranged in sequence from the outside to the inside.

[0009] The thermoelectric unit array includes a plurality of thermoelectric units arranged in series,

[0010] The thermoelectric unit comprises an n-type thermoelectric arm, a p-type thermoelectric arm and an electrode. The n-type thermoelectric arm and the p-type thermoelectric arm are arranged in parallel and connected to form a π-type structure through the electrode.

[0011] Furthermore, the series connection of the thermoelectric units is as follows: the n-type thermoelectric arms and the p-type thermoelectric arms are arranged alternately in sequence and connected through electrodes to achieve electrical series connection.

[0012] Furthermore, the n-type thermoelectric arm is in the shape of a thin long strip, the p-type thermoelectric arm is in the shape of a thin long strip or a thin line, and the electrode is in the shape of a thin film.

[0013] Furthermore, the n-type thermoelectric arm, the p-type thermoelectric arm, the electrode and the packaging body are all made of flexible materials.

[0014] Furthermore, the material of the n-type thermoelectric arm is Ag. 1.96 S 0.5 Se 0.25 Te 0.25 Flexible amorphous thermoelectric material or any other flexible n-type room temperature thermoelectric material; the material of the p-type thermoelectric arm is Cr 10 Ni 90 alloy; the electrode material is Cu; the package body material is polydimethylsiloxane, polyimide or Ecoflex silicone.

[0015] Preferably, the material of the n-type thermoelectric arm is Ag. 1.96 S 0.5 Se 0.25 Te 0.25 Flexible amorphous thermoelectric material; the material of the p-type thermoelectric arm is Cr 10 Ni 90 Alloy wire, electrode material is Cu foil.

[0016] Preferably, the material of the package body is insulating polyimide tape.

[0017] Preferably, the packaged flexible thermoelectric device is installed inside the mask with the help of double-sided tape.

[0018] Furthermore, when wearing a portable mask and exhaling, the end of the flexible thermoelectric device close to the center of the mask is the hot end, and the end away from the center of the mask is the cold end, and the opposite is true when inhaling. The flexible thermoelectric device is driven by the airflow temperature of breathing, and a temperature difference is established at the two ends of the thermoelectric arm. The temperature difference is converted into an electrical signal output based on the Seebeck effect of the thermoelectric material to monitor breathing.

[0019] On the other hand, the present invention also provides a method for preparing any of the portable masks described above, comprising the following steps:

[0020] S1, preparation of n-type thermoelectric arm: according to the stoichiometric ratio, Ag 1.96 S 0.5 Se 0.25 Te 0.25Ag is obtained after mechanical alloying 1.96 S 0.5 Se 0.25 Te 0.25 The flake sample was cold pressed and annealed to obtain Ag 1.96 S 0.5 Se 0.25 Te 0.25 Ingot, high temperature rolling Ag 1.96 S 0.5 Se 0.25 Te 0.25 The ingot is cast to obtain a flexible long strip sample, and the flexible long strip sample is ground, polished and cut to obtain an n-type thermoelectric arm;

[0021] S2, preparation of p-type thermoelectric arm: Cr 10 Ni 90 The alloy is arc-melted and subjected to high-temperature strip-spinning treatment to obtain Cr 10 Ni 90 Alloy sheet samples, after cutting, p-type thermoelectric arms are obtained;

[0022] S3, preparing a thermoelectric unit array: placing the n-type thermoelectric arm obtained in step S1 and the p-type thermoelectric arm obtained in step S2 in parallel, and connecting them into a π-type structure through electrodes to achieve electrical series connection, thereby obtaining a π-type thermoelectric unit; the n-type thermoelectric arm and the p-type thermoelectric arm of each π-type thermoelectric unit are alternately arranged in sequence, and connected through electrodes to achieve electrical series connection, thereby obtaining a thermoelectric unit array;

[0023] S4, packaging: using a packaging body to package the thermoelectric unit array obtained in step S3 to obtain a flexible thermoelectric device;

[0024] S5, installing the flexible thermoelectric device obtained in step S4 inside the mask to obtain a portable mask.

[0025] Further, in step S1, Ag 1.96 S 0.5 Se 0.25 Te 0.25 The sheet sample is subjected to secondary discharge plasma sintering to obtain an ASST thin sheet sample, and the ASST thin sheet sample is ground, polished and cut to obtain an n-type thermoelectric arm.

[0026] Furthermore, the connection between the n-type thermoelectric arm, the p-type thermoelectric arm and the electrode is achieved by welding or silver paste.

[0027] In a third aspect, the present invention also provides an application of any of the portable masks described above in the field of respiratory monitoring.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention provides a portable mask for respiratory monitoring, and a preparation method and application thereof. The mask is provided with a flexible thermoelectric device, wherein the flexible thermoelectric device comprises a packaging body and a thermoelectric unit array arranged in sequence from the outside to the inside, wherein the thermoelectric unit array comprises a plurality of thermoelectric units arranged in series, wherein the thermoelectric unit comprises an n-type thermoelectric arm, a p-type thermoelectric arm and an electrode, wherein the n-type thermoelectric arm and the p-type thermoelectric arm are arranged in parallel and connected to form a π-type structure through an electrode, thereby obtaining a π-type thermoelectric unit, wherein the n-type thermoelectric arm and the p-type thermoelectric arm of each π-type thermoelectric unit are alternately arranged in sequence and connected to achieve electrical series connection through an electrode, thereby obtaining a thermoelectric unit array, wherein the thermoelectric unit array is encapsulated in a packaging body, thereby obtaining a flexible thermoelectric device, and finally the obtained flexible thermoelectric device is adhered to the inside of a 3D mask using double-sided tape, thereby obtaining a portable mask for respiratory monitoring. When exhaling, the end of the flexible thermoelectric device close to the center of the mask is the hot end, and the end away from the center of the mask is the cold end. The opposite is true when inhaling. The Seebeck effect is used to convert the temperature difference signal at both ends of the flexible thermoelectric device into an electrical signal for respiratory monitoring.

[0030] (2) The portable mask for respiratory monitoring provided by the present invention has a built-in flexible thermoelectric device, which uses the thermoelectric effect to directly convert the temperature difference between the two ends of the device into an electrical signal, and does not rely on an external power supply. In addition, the flexible thermoelectric device is installed inside the mask, has a stable support surface, and is not in direct contact with the skin. Compared with the patch sensor that is in direct contact with the skin, there is no need to consider the problem of biocompatibility.

[0031] (3) The present invention provides a portable mask for respiratory monitoring. The portable mask has a built-in flexible thermoelectric device with a thickness of micrometer level after hot rolling and polishing. At the same time, the material is flexible and the device as a whole is lightweight, thus overcoming the problems of bulkiness and rigidity of traditional TEG.

[0032] (4) Compared with other self-powered respiratory sensors, the portable mask for respiratory monitoring provided by the present invention is not tightly attached to the chest and abdomen by means of straps, and does not rely on the chest and abdominal movements generated during breathing to monitor respiration. Instead, the sensor is driven by the airflow temperature of respiration. Respiration can be monitored while wearing a protective mask, so there is no problem of wearing comfort and it is not easy to generate motion artifacts.

[0033] (5) The present invention provides a portable mask for respiratory monitoring, a preparation method and an application thereof. The preparation method does not involve a complicated manufacturing process and expensive micro-machining, has low cost, and is easy to achieve large-scale production. It is expected to be popularized in the direction of continuous daily monitoring and personalized medical care. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1This is the overall structure diagram of the portable mask with built-in flexible thermoelectric device of the present invention;

[0035] Figure 2 A front perspective view of a portable mask with a built-in flexible thermoelectric device according to the present invention;

[0036] Figure 3 A side perspective view of a portable mask with a built-in flexible thermoelectric device according to the present invention;

[0037] Figure 4 A perspective view of the structure of a longitudinal π-type thermoelectric unit of the present invention;

[0038] Figure 5 A perspective view of the structure of a transverse π-type thermoelectric unit of the present invention;

[0039] Figure 6 It is a perspective view of the overall structure of the flexible thermoelectric device of the present invention.

[0040] Description of reference numerals:

[0041] 1-n-type thermoelectric arm, 2-p-type thermoelectric arm, 3-electrode, 4-commercial 3D mask DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0043] The present invention provides a portable mask, on which a flexible thermoelectric device is provided. The flexible thermoelectric device includes a packaging body and a thermoelectric unit array arranged in sequence from the outside to the inside. The thermoelectric unit array includes a plurality of thermoelectric units arranged in series. The thermoelectric unit includes an n-type thermoelectric arm 1, a p-type thermoelectric arm 2 and an electrode 3. The n-type thermoelectric arm 1 is arranged in parallel with the p-type thermoelectric arm 2 and is connected to form a π-type structure through the electrode 3.

[0044] In some specific embodiments, the series connection of the thermoelectric units is as follows: the n-type thermoelectric arms 1 and the p-type thermoelectric arms 2 are alternately arranged in sequence and connected through electrodes 3 to achieve electrical series connection.

[0045] In some specific embodiments, the n-type thermoelectric arm 1 is in the shape of a thin long strip, the p-type thermoelectric arm 2 is in the shape of a thin long strip or a thin line, and the electrode 3 is in the shape of a thin film.

[0046] In some specific implementations, the n-type thermoelectric arm 1 , the p-type thermoelectric arm 2 , the electrode 3 and the packaging body are all made of flexible materials.

[0047] In some specific embodiments, the material of the n-type thermoelectric arm 1 is Ag. 1.96 S0.5 Se 0.25 Te 0.25 Flexible amorphous thermoelectric material or any other flexible n-type room temperature thermoelectric material; the material of the p-type thermoelectric arm 2 is Cr 10 Ni 90 alloy; the material of the electrode 3 is Cu; the material of the package body is any one of polydimethylsiloxane, polyimide or Ecoflex silicone.

[0048] In some specific embodiments, when wearing the mask 4 and exhaling, the end of the flexible thermoelectric device close to the center of the mask 4 is the hot end, and the end away from the center of the mask 4 is the cold end, and the opposite is true when inhaling. The flexible thermoelectric device is driven by the air flow temperature of breathing, and a temperature difference is established at both ends of the thermoelectric arm. The temperature difference is converted into an electrical signal output based on the Seebeck effect of the thermoelectric material to monitor breathing.

[0049] The portable mask is prepared by the following method:

[0050] S1, preparation of n-type thermoelectric arm 1: According to the stoichiometric ratio, Ag 1.96 S 0.5 Se 0.25 Te 0.25 Ag is obtained after mechanical alloying 1.96 S 0.5 Se 0.25 Te 0.25 The flake sample was cold pressed and annealed to obtain Ag 1.96 S 0.5 Se 0.25 Te 0.25 Ingot, high temperature rolling Ag 1.96 S 0.5 Se 0.25 Te 0.25 The ingot is cast to obtain a flexible long strip sample, and the flexible long strip sample is ground, polished, and cut to obtain an n-type thermoelectric arm 1;

[0051] S2, preparation of p-type thermoelectric arm 2: Cr 10 Ni 90 The alloy is arc-melted and subjected to high-temperature strip-spinning treatment to obtain Cr 10 Ni 90 The alloy sheet sample is cut to obtain a p-type thermoelectric arm 2;

[0052] S3, preparing a thermoelectric unit array: placing the n-type thermoelectric arm 1 obtained in step S1 and the p-type thermoelectric arm 2 obtained in step S2 in parallel, and connecting them into a π-type structure through an electrode 3 to achieve electrical series connection, thereby obtaining a π-type thermoelectric unit; the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 of each π-type thermoelectric unit are alternately arranged in sequence, and connected through an electrode 3 to achieve electrical series connection, thereby obtaining a thermoelectric unit array;

[0053] S4, packaging: using a packaging body to package the thermoelectric unit array obtained in step S3 to obtain a flexible thermoelectric device;

[0054] S5, installing the flexible thermoelectric device obtained in step S4 inside the mask 4 to obtain a portable mask.

[0055] In some specific embodiments, in step S1, Ag 1.96 S 0.5 Se 0.25 Te 0.25 The sheet sample is subjected to secondary discharge plasma sintering to obtain an ASST thin sheet sample, and the ASST thin sheet sample is ground, polished, and cut to obtain an n-type thermoelectric arm 1.

[0056] In some specific implementations, the connection between the n-type thermoelectric arm 1 , the p-type thermoelectric arm 2 and the electrode 3 is achieved by welding or silver paste.

[0057] The above-mentioned portable mask can be applied in the field of respiratory monitoring.

[0058] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available. For example, the electroplating solution and anti-oxidation passivation solution used in the following examples or comparative examples are purchased from Beichen Hardware Technology Co., Ltd.

[0059] Example 1

[0060] In this embodiment, a method for preparing and installing a flexible thermoelectric device built into a portable mask for respiratory monitoring includes the following steps:

[0061] 1) Select Ag 1.96 S 0.5 Se 0.25 Te 0.25 The flexible amorphous thermoelectric material is an n-type thermoelectric material. Each element is sampled according to the stoichiometric ratio in a nitrogen glove box. 6.5782 g of Ag powder, 0.4988 g of S powder, 0.6142 g of Se powder, and 0.9925 g of Te powder are weighed and put into a ball mill for 20 hours of high-energy ball milling at a ball milling speed of 8000 RPM and a ball milling temperature of 25 ° C to obtain Ag. 1.96 S 0.5 Se 0.25 Te 0.25 Flaky powder.

[0062] 2) Take 5g Ag 1.96 S 0.5 Se 0.25 Te 0.25The flaky powder was loaded into a stainless steel mold with a diameter of 12.7 mm. A cold pressing process was used. A pressure of 60 MPa was applied to it at 25°C and then fixed and maintained for 20 minutes. A block with a height of 5 mm was obtained after it was taken out.

[0063] 3) The block obtained in step 2) is annealed in a rapid annealing furnace, and the temperature is raised from room temperature to 200°C at a rate of 50°C / min, and kept at 200°C for 10 minutes, and then taken out after it cools down to room temperature. The block sample is lightly polished with fine-grit sandpaper to remove a small amount of sulfur, selenium and tellurium volatilized due to high temperature.

[0064] 4) Use a constant temperature heating table to soften the block sample obtained in step 3), and the temperature of the heating table must not be higher than the annealing temperature. The softened sample is quickly transferred to an electric heated roller machine, and the temperature of the upper roller is set to 175°C and the temperature of the lower roller is set to 200°C. At the beginning of hot rolling, the rotation speed of the roller should be slightly slower, and the displacement of the upper and lower rollers should be slowly reduced to allow the sample to gradually extend to avoid the block sample from breaking into pieces. After the sample becomes thinner, the roller rotation speed can be increased again. After repeated hot rolling, the sample is gradually thinned, and finally a 200-micron thin sheet can be obtained.

[0065] 5) The thin slice is polished, ground, and cut to finally obtain two thin and long strip n-type thermoelectric arms 1 with sizes of 25 mm×2 mm×0.2 mm and 50 mm×2 mm×0.2 mm.

[0066] 6) Perform metallization treatment on the n-type thermoelectric arm 1, connect the two ends of the n-type thermoelectric arm 1 to the negative electrode of the adjustable power supply, connect the nickel sheet to the positive electrode, put the two into the electroplating solution, turn on the power supply, adjust the current until the two ends of the n-type thermoelectric arm 1 are plated with a uniform layer of nickel, then put it into the anti-oxidation passivation solution and soak it for 5 minutes before taking it out for use.

[0067] 7) A Cr-Ni alloy thermocouple wire is selected as the p-type thermoelectric arm 2, the diameter of the Cr-Ni alloy thermocouple wire is 0.1 mm, and two types of filamentary p-type thermoelectric arms 2 with sizes of Ф0.1 mm×25 mm and Ф0.1 mm×50 mm are obtained by cutting.

[0068] 8) The n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 with matching lengths are placed in parallel, and then connected to the copper foil electrode 3 by solder paste. The sizes of the copper foil electrode 3 are 6mm×2mm×0.1mm and 2mm×2mm×0.1mm respectively. The n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 with a length of 25mm are connected by welding with a copper foil electrode 3 of 6mm×2mm×0.1mm to form a longitudinal π-type thermoelectric unit for electrical series connection; the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 with a length of 50mm are connected by welding with a copper foil electrode 3 of 6mm×2mm×0.1mm to form a transverse π-type thermoelectric unit for electrical series connection. Figure 4 As shown, the lateral π-type thermoelectric unit is Figure 5 The specific welding process is as follows: the solder paste used is high temperature lead-free solder paste Sn 99 Ag 0.3 Cu 0.7 , whose melting point is 227℃. For the n-type thermoelectric arm 1, Sn 99 Ag 0.3 Cu 0.7 Apply it on the nickel-plated layer of the n-type thermoelectric arm 1, and then place it on a 6mm×2mm×0.1mm copper foil; for the p-type thermoelectric arm 2, sandwich it between 6mm×2mm×0.1mm and 2mm×2mm×0.1mm copper foils, and apply solder paste in the middle. Transfer the π-type thermoelectric unit to the heating table, heat the temperature from room temperature to 220℃ at a heating rate of 3-5℃ / s, keep it warm for 2min, so that the solvent in the solder paste gradually evaporates, and then quickly heat it to 280℃ to completely melt the solder paste. After keeping warm for 1min, turn off the heating table and let it cool naturally to room temperature to form a stable solder joint.

[0069] 9) If Figure 6 As shown, the two π-type thermoelectric units obtained in step 8) are placed in the four directions of top, right, bottom and left in sequence, where the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 intersect, a copper foil electrode 3 with a size of 2mm×2mm×0.1mm is soldered and covered on the p-type thermoelectric arm 2 by solder paste to form an electrical series connection. The solder paste used in step 9) is a low-temperature lead-free solder paste Sn 42 Bi 58 , its melting point is 138℃, place the p-type thermoelectric arm 2 on the nickel-plated layer of the n-type thermoelectric arm 1, apply solder paste and then cover it with a layer of 2mm×2mm×0.1mm copper foil. Transfer it to the heating table, heat it from room temperature to 130℃ at a heating rate of 3-5℃ / s, keep it warm for 2min, so that the solvent in the solder paste gradually evaporates, and then quickly heat it to 180℃ to completely melt the solder paste. After keeping warm for 1min, turn off the heating table and let it cool naturally to room temperature to form a stable solder joint. At this point, the electrical connection between the π-type thermoelectric unit and the π-type thermoelectric unit is completed.

[0070] 10) As Figure 6 As shown, two pairs of π-type thermoelectric units are connected in four directions: up, right, down, and left, to form a thermoelectric unit array as a whole. Note that the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 located in the left direction do not need to be connected to the copper foil electrode 3 with a size of 6mm×2mm×0.1mm, but are connected to the wire for convenient later access to the circuit to test the sensing performance.

[0071] 11) Using polyimide tape to encapsulate the thermoelectric unit array obtained in step 10) to obtain a flexible thermoelectric device.

[0072] 12) Using double-sided tape, the flexible thermoelectric device obtained in step 11) is adhered to the inside of a commercial 3D mask to complete the installation, thereby obtaining a portable mask for respiratory monitoring, such as Figure 1-3 shown.

[0073] Example 2

[0074] This embodiment is basically the same as Embodiment 1, except that:

[0075] In this example, the preparation method of the n-type thermoelectric material is changed to ball milling and discharge plasma sintering, and then it is polished to obtain a flexible sheet with a thickness of micrometer level. In addition, it is different from the preparation sequence in Example 1, in which the π-type thermoelectric unit is first prepared by high-temperature lead-free solder paste welding, and then the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 between the π-type thermoelectric units in four directions are welded with low-temperature lead-free solder paste; in this embodiment, only low-temperature lead-free solder paste is used, and the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 and the copper foil electrodes of two different sizes are first placed on the glass plate according to the flexible thermoelectric device structure in Example 1, and at the same time, all parts that need to be welded are coated with low-temperature lead-free solder paste, and then transferred to the heating table to complete the welding. Note that the flexible thermoelectric device structures of Examples 1 and 2 are the same.

[0076] In this embodiment, a method for preparing and installing a flexible thermoelectric device built into a portable mask for respiratory monitoring includes the following steps:

[0077] 1) Select Ag 1.96 S 0.5 Se 0.25 Te 0.25 The flexible amorphous thermoelectric material is an n-type thermoelectric material. Each element is sampled according to the stoichiometric ratio in a nitrogen glove box. 6.5782 g of Ag powder, 0.4988 g of S powder, 0.6142 g of Se powder, and 0.9925 g of Te powder are weighed and put into a ball mill for 20 hours of high-energy ball milling at a ball milling speed of 8000 RPM and a ball milling temperature of 25 ° C to obtain Ag. 1.96 S 0.5 Se 0.25 Te 0.25 Flaky powder.

[0078] 2) Prepare ASST thin sheets by spark plasma sintering. Weigh 7g Ag 1.96 S 0.5 Se 0.25 Te 0.25 The flake powder is first loaded into a 30mm mold, and the SPS heating rate is set to 50℃ / min until the temperature reaches 200 degrees, and the temperature is kept at 200 degrees for half an hour. The pressure is set to 35KN, and a flake with a thickness of 1.24mm can be obtained. Then change to a 50mm mold, heat it to 400 degrees at 50℃ / min, and keep it at 400 degrees for 20 minutes. The pressure setting is slowly increased from 35KN to 125KN, and an ASST flake with a diameter of 46mm and a thickness of 0.8mm can be obtained.

[0079] 3) The ASST slice is polished, ground, and cut to finally obtain two thin strip-shaped n-type thermoelectric arms 1 with sizes of 25 mm×2 mm×0.2 mm and 50 mm×2 mm×0.2 mm.

[0080] 4) Perform metallization treatment on the n-type thermoelectric arm 1, connect the two ends of the n-type thermoelectric arm 1 to the negative electrode of the adjustable power supply, connect the nickel sheet to the positive electrode, put the two into the electroplating solution, turn on the power supply, adjust the current until the two ends of the n-type thermoelectric arm 1 are plated with a uniform layer of nickel, then put it into the anti-oxidation passivation solution and soak it for 5 minutes before taking it out for use.

[0081] 5) A Cr-Ni alloy thermocouple wire is selected as the p-type thermoelectric arm 2, the diameter of the Cr-Ni alloy thermocouple wire is 0.1 mm, and two types of filamentary p-type thermoelectric arms 2 with sizes of Ф0.1 mm×25 mm and Ф0.1 mm×50 mm are obtained by cutting.

[0082] 6) An n-type thermoelectric arm 1 with a size of 25 mm × 2 mm × 0.2 mm and a p-type thermoelectric arm 2 with a size of 0.1 mm × 25 mm are placed longitudinally and parallelly at both ends of a copper foil electrode 3 with a size of 6 mm × 2 mm × 0.1 mm and coated with solder paste, and a layer of copper foil with a size of 2 mm × 2 mm × 0.1 mm and coated with solder paste is covered on the top of the p-type thermoelectric arm 2 to obtain a longitudinal π-type thermoelectric unit, such as Figure 4 shown.

[0083] 7) An n-type thermoelectric arm 1 with a size of 50 mm × 2 mm × 0.2 mm and a p-type thermoelectric arm 2 with a size of 0.1 mm × 50 mm are placed horizontally and parallelly at both ends of a copper foil electrode 3 with a size of 6 mm × 2 mm × 0.1 mm and coated with solder paste, and a copper foil electrode 3 with a size of 2 mm × 2 mm × 0.1 mm and coated with solder paste is covered on the p-type thermoelectric arm 2 to obtain a horizontal π-type thermoelectric unit, such as Figure 5 shown.

[0084] 8) If Figure 6 As shown, two pairs of π-type thermoelectric units are connected in four directions, namely, up, right, down, and left, to form a thermoelectric unit array as a whole. The n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 of the longitudinal π-type thermoelectric unit obtained in step 6) and the transverse π-type thermoelectric unit obtained in step 7) are arranged alternately, and the p-type thermoelectric arm 2 is placed on the nickel-plated layer of the n-type thermoelectric arm 1. Solder paste is applied to the junction of the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2, and a layer of copper foil with a size of 2mm×2mm×0.1mm and coated with solder paste is covered on the p-type thermoelectric arm 2. Note that the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 located in the left direction do not need to be connected to the copper foil electrode 3 with a size of 6mm×2mm×0.1mm, but are connected to the wire, which is convenient for later circuit connection to test the sensing performance.

[0085] At this point, steps 6), 7), and 8) have constructed the overall structure of the flexible thermoelectric device, forming the vertical π-type thermoelectric units in the upper and lower positions and the horizontal π-type thermoelectric units in the left and right positions, and the area where the two meet and need to be welded has been prepared. The solder paste used in steps 6), 7), and 8) is low-temperature lead-free solder paste Sn 42 Bi 58 , its melting point is 138℃.

[0086] 9) The thermoelectric unit array structure constructed in step 8) is transferred to a heating platform with the help of a glass plate, and the temperature is heated from room temperature to 130°C at a heating rate of 3 to 5°C / s, and kept at this temperature for 2 minutes to allow the solvent in the solder paste to gradually evaporate, and then the temperature is quickly raised to 180°C to completely melt the solder paste. After keeping at this temperature for 1 minute, the heating platform is turned off and allowed to cool naturally to room temperature to form a stable solder joint.

[0087] 10) Using polyimide tape to encapsulate the thermoelectric unit array obtained in step 9) to obtain a flexible thermoelectric device.

[0088] 11) Using double-sided tape, the flexible thermoelectric device obtained in step 10) is adhered to the inside of a commercial 3D mask to complete the installation, thereby obtaining a portable mask for respiratory monitoring, such as Figure 1-3 shown.

[0089] The portable masks for respiratory monitoring prepared in Examples 1-2 were subjected to performance tests:

[0090] The detection method is: using Keithley's 4200A-SCS semiconductor parameter analyzer to test the Vt of the mask under different breathing modes, where V is voltage and t is time. They are fast breathing, normal breathing and deep breathing. When the subject wears the mask, the nasal airflow temperature is higher than the ambient temperature when exhaling, and the center temperature of the n-type thermoelectric arm (1) and the p-type thermoelectric arm (2) is higher than the edge temperature, causing the device output voltage to rise first; when inhaling, the center temperature of the n-type thermoelectric arm (1) and the p-type thermoelectric arm (2) is lower than the edge temperature, causing the device output voltage to drop later. The test mode is sampling, the test speed is set to Quiet, and data is recorded every 0.05 seconds. The normal breathing frequency is usually between 12 and 20 times per minute, so we recorded the breathing situation for one minute. The breathing frequency per minute can be used to determine whether the subject's breathing is normal or whether there is potential danger.

[0091] The Vt curves under different breathing modes were detected and the detection results were analyzed as shown in Table 1.

[0092] Table 1 Vt curve analysis results of portable masks in different breathing modes in Example 1-2

[0093] Rapid breathing Normal breathing Take a deep breath Respiratory rate / times 25 12 9 Average respiratory intensity / mV 0.18 0.33 0.42

[0094] It can be seen from Table 1 that there are obvious differences in breathing frequency and breathing intensity under different breathing modes, indicating that the portable mask of the present invention can distinguish different breathing states. The breathing frequencies of rapid breathing and deep breathing are 25 and 9 respectively, both of which are not between 12-20, indicating that this breathing state may be potentially dangerous.

[0095] According to the test results, the flexible thermoelectric device built into the mask of the present invention can distinguish different breathing states and generate output signals of different intensities. That is, the portable mask with built-in flexible thermoelectric device can be used to monitor breathing and evaluate and warn of some potential disease risks.

[0096] In summary, the portable mask for respiratory monitoring of the present invention has a built-in flexible thermoelectric device, including: a thermoelectric unit, a conductive electrode, and a polyimide packaging tape. Among them, the n-type thermoelectric arm in the thermoelectric unit is a thin strip, the p-type thermoelectric arm is a filament, and is connected with an electrode to form a transverse / longitudinal π-type thermoelectric unit, and then the longitudinal π-type thermoelectric unit and the transverse π-type thermoelectric unit are electrically connected in series to form a thermoelectric unit array, and finally packaged with PI tape to obtain a flexible thermoelectric device, and the prepared flexible thermoelectric device is adhered to the inside of the 3D mask with the help of double-sided tape, so as to complete the preparation of a portable mask for respiratory monitoring. When the subject wears the mask, the nasal airflow temperature is higher than the ambient temperature when exhaling, and the center temperature of the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 is higher than the edge temperature, resulting in a positive rise in the output voltage of the device; when inhaling, the center temperature of the n-type thermoelectric arm 1 and the p-type thermoelectric arm 2 is lower than the edge temperature, resulting in a reverse rise in the output voltage of the device. The flexible thermoelectric device uses the thermoelectric effect to directly convert the temperature difference between the two ends of the device into an electrical signal without relying on an external power supply. According to the test results, the mask can distinguish different breathing states and generate output signals of different intensities, which can evaluate and warn of some potential disease risks.

[0097] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A portable mask for respiratory monitoring, characterized in that: The mask (4) is provided with a flexible thermoelectric device, the flexible thermoelectric device comprising a packaging body and a thermoelectric unit array arranged in sequence from the outside to the inside, The thermoelectric unit array includes a plurality of thermoelectric units arranged in series, The thermoelectric unit comprises an n-type thermoelectric arm (1), a p-type thermoelectric arm (2) and an electrode (3); the n-type thermoelectric arm (1) and the p-type thermoelectric arm (2) are arranged in parallel and connected to form a π-type structure through the electrode (3).

2. A portable mask for respiratory monitoring according to claim 1, characterized in that: The series connection of the thermoelectric units is as follows: the n-type thermoelectric arms (1) and the p-type thermoelectric arms (2) are arranged alternately in sequence and connected via electrodes (3) to achieve electrical series connection.

3. A portable mask for respiratory monitoring according to claim 1, characterized in that: The n-type thermoelectric arm (1) is in the shape of a thin long strip, the p-type thermoelectric arm (2) is in the shape of a thin long strip or a thin line, and the electrode (3) is in the shape of a thin film.

4. A portable mask for respiratory monitoring according to claim 1, characterized in that: The n-type thermoelectric arm (1), the p-type thermoelectric arm (2), the electrode (3) and the packaging body are all made of flexible materials.

5. A portable mask for respiratory monitoring according to claim 4, characterized in that: The material of the n-type thermoelectric arm (1) is Ag. 1.96 S 0.5 Se 0.25 Te 0.25 Any one of flexible amorphous thermoelectric materials or other flexible n-type room temperature thermoelectric materials; The material of the p-type thermoelectric arm (2) is Cr 10 Ni 90 alloy; The material of the electrode (3) is Cu; The material of the package body is any one of polydimethylsiloxane, polyimide or Ecoflex silicone.

6. A portable mask for respiratory monitoring according to claim 1, characterized in that: When wearing the mask (4) and exhaling, the end of the flexible thermoelectric device close to the center of the mask (4) is the hot end, and the end away from the center of the mask (4) is the cold end, and vice versa when inhaling; The airflow temperature of breathing is used to drive the flexible thermoelectric device, establishing a temperature difference at both ends of the thermoelectric arm. Based on the Seebeck effect of the thermoelectric material, the temperature difference is converted into an electrical signal output to monitor breathing.

7. A method for preparing a portable mask for respiratory monitoring according to any one of claims 1 to 6, characterized in that: The steps include: S1, preparation of n-type thermoelectric arm (1): According to the stoichiometric ratio, Ag 1.96 S 0.5 Se 0.25 Te 0.25 Ag is obtained after mechanical alloying 1.96 S 0.5 Se 0.25 Te 0.25 The flake sample was cold pressed and annealed to obtain Ag 1.96 S 0.5 Se 0.25 Te 0.25 Ingot, high temperature rolling Ag 1.96 S 0.5 Se 0.25 Te 0.25 The ingot is cast to obtain a flexible long strip sample, and the flexible long strip sample is ground, polished, and cut to obtain an n-type thermoelectric arm (1); S2, preparation of p-type thermoelectric arm (2): Cr 10 Ni 90 The alloy is arc-melted and subjected to high-temperature strip-spinning treatment to obtain Cr 10 Ni 90 The alloy sheet sample is cut into p-type thermoelectric arms (2); S3, preparing a thermoelectric unit array: placing the n-type thermoelectric arm (1) obtained in step S1 and the p-type thermoelectric arm (2) obtained in step S2 in parallel, and connecting them into a π-type structure through an electrode (3) to achieve electrical series connection, thereby obtaining a π-type thermoelectric unit; the n-type thermoelectric arm (1) and the p-type thermoelectric arm (2) of each π-type thermoelectric unit are alternately arranged in sequence, and connected through an electrode (3) to achieve electrical series connection, thereby obtaining a thermoelectric unit array; S4, packaging: using a packaging body to package the thermoelectric unit array obtained in step S3 to obtain a flexible thermoelectric device; S5, installing the flexible thermoelectric device obtained in step S4 inside the mask (4) to obtain a portable mask.

8. The method for preparing a portable mask for respiratory monitoring according to claim 7, characterized in that: In step S1, Ag 1.96 S 0.5 Se 0.25 Te 0.25 The sheet sample is subjected to secondary discharge plasma sintering to obtain an ASST thin sheet sample, and the ASST thin sheet sample is ground, polished, and cut to obtain an n-type thermoelectric arm (1).

9. The method for preparing a portable mask for respiratory monitoring according to claim 7, characterized in that: The connection between the n-type thermoelectric arm (1), the p-type thermoelectric arm (2) and the electrode (3) is achieved by welding or silver paste.

10. Use of a portable mask as described in any one of claims 1 to 6 in the field of respiratory monitoring.

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