Respiration monitoring system based on screen printing and manufacturing method thereof

Abstract

The invention belongs to the technical field of respiration monitoring, provides a respiration monitoring system based on screen printing and a manufacturing method thereof, and aims to solve the problems of low integration level, complicated operation, high use cost and the like of existing respiration monitoring equipment. The device is composed of a flexible circuit board, a sensor and an electronic component. The sensor comprises a strain sensor and a temperature sensor, and the strain sensor and the temperature sensor are prepared on the surface of the flexible circuit board through a silk-screen printing technology; the electronic components are attached to the surface of the flexible circuit board, and the sensor and the electronic components are in conductive interconnection through the flexible circuit board. The respiration monitoring system is attached to the lower portion of a nostril and used for monitoring nasal respiration airflow. According to the manufacturing method based on the silk-screen printing technology, integration of the flexible circuit board and the sensor is achieved, the nose breathing airflow and temperature monitoring function is achieved, the airflow detection sensitivity of a monitoring system is improved, and the breathing monitoring accuracy and functionality are also improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of respiratory monitoring, and specifically provides a respiratory monitoring system based on screen printing and a manufacturing method thereof. Background Art

[0002] Respiratory monitoring is an important means of checking the health status of the human body, and is usually used for the diagnosis of obstructive sleep apnea syndrome (OSAS). Polysomnography (PSG) is usually used clinically to monitor the patient's sleep breathing, but it has the problems of complex operation and high cost. At present, the publicly available wearable respiratory monitoring equipment usually adopts a separate design, that is, the sensor and the circuit board are designed and processed separately, and then the sensor and the circuit board are connected using a long wire, which limits the integration and portability of the equipment, thereby increasing the difficulty of operating the equipment. Summary of the invention

[0003] The purpose of the present invention is to propose a respiratory monitoring system based on screen printing and a manufacturing method thereof in view of the problems of low integration, complex operation, high cost of use, etc. in the respiratory monitoring equipment in the prior art.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A respiratory monitoring system based on screen printing is composed of a flexible circuit board, a sensor and electronic components; wherein the sensor includes: a strain sensor and a temperature sensor, and the strain sensor and the temperature sensor are prepared on the surface of the flexible circuit board by a screen printing process; the electronic components are mounted on the surface of the flexible circuit board, and the sensor and each electronic component are conductively interconnected through the flexible circuit board; the respiratory monitoring system is attached under the nostrils to monitor nasal respiratory airflow.

[0006] Furthermore, the temperature sensor is made of a temperature-sensitive material film, and the temperature-sensitive material film is printed on the surface of the flexible circuit board by a screen printing process.

[0007] Furthermore, the strain sensor adopts a cantilever beam structure, which is composed of a base, a strain electrode and an elastic beam. The strain electrode is attached to the lower surface of the elastic beam, the fixed end of the elastic beam is fixed on the base, and the free end is naturally warped upward; the base, the strain electrode and the elastic beam are printed on the surface of the flexible circuit board in sequence through a screen printing process. During the printing process, a sacrificial layer is printed under the elastic beam, and the strain electrode and the elastic beam are printed on the sacrificial layer in sequence. After removing the sacrificial layer, the free end of the elastic beam naturally warps upward to form a cantilever beam structure.

[0008] Furthermore, the strain electrode is composed of a brittle conductive material layer and an elastic conductive material layer, the elastic conductive material layer is located in the upper layer and attached to the lower surface of the elastic beam, and the brittle conductive material layer is located in the lower layer and attached to the lower surface of the elastic conductive material layer.

[0009] Furthermore, the electronic components include: all components and batteries etc. constituting the minimum system of the single chip microcomputer.

[0010] Furthermore, the method for manufacturing the respiratory monitoring system based on screen printing comprises the following steps:

[0011] S1: Pre-processing a flexible circuit board according to the conductive interconnection relationship between the sensor and various electronic components;

[0012] S2: Printing a graphic temperature-sensitive material film on the surface of the flexible circuit board by screen printing and curing, with both ends of the temperature-sensitive material film covering the surface of the reserved exposed electrodes of the flexible circuit board, and the thickness of the temperature-sensitive material film is 5 to 20 μm;

[0013] S3: Printing the base on the surface of the flexible circuit board by screen printing and curing, printing again, curing, and repeating the overprinting multiple times to make the base thickness reach 50-100 μm;

[0014] S4: Printing a sacrificial layer on the surface of the flexible circuit board by screen printing, and performing multiple overprinting cycles to make the sacrificial layer have the same thickness as the base;

[0015] S5: Printing a graphic brittle conductive material layer on the surface of the sacrificial layer and the base by screen printing and curing, and extending both ends of the brittle conductive material layer to cover the surface of the reserved exposed electrode of the flexible circuit board; the thickness of the brittle conductive material layer is 5 to 10 μm;

[0016] S6: printing an elastic conductive material layer on the surface of the brittle conductive material layer by screen printing and curing the layer, wherein the brittle conductive material layer and the elastic conductive material layer together constitute a strain electrode, and the thickness of the elastic conductive material layer is 10 to 30 μm;

[0017] S7: printing an elastic beam covering the strain electrode on the surface of the sacrificial layer and the base by screen printing and curing, and performing multiple overprinting cycles to make the thickness of the elastic beam reach 50 to 150 μm;

[0018] S8: placing the semi-finished device in warm water at 50 to 80° C. for ultrasonic cleaning for 10 to 30 minutes to remove the sacrificial layer, and then drying in an environment at 100 to 150° C.;

[0019] S9: Mount the required electronic components on the surface of the flexible printed circuit board to form a respiratory monitoring system.

[0020] Furthermore, in step S2, the temperature sensitive material is graphene or carbon nanotubes; in step S3, the base material is epoxy resin, acrylic resin or acrylic resin; in step S4, the sacrificial layer material is a mixture of trimethylolethane, trimethylolpropane, cyclohexanol and propylene glycol; in step S5, the brittle conductive material is conductive carbon paste, conductive copper paste or conductive silver paste; in step S6, the elastic conductive material is a mixture of conductive particles (such as silver nanowires, carbon nanotubes, silver nanoparticles, carbon black) and elastic resin material, wherein the mass fraction of the conductive particles is between 5% and 15%; in step S7, the elastic beam material is polydimethylsiloxane or silicone.

[0021] Compared with the prior art, the beneficial effect of the present invention is to provide a respiratory monitoring system based on screen printing and a manufacturing method thereof, including the following advantages:

[0022] 1. The strain sensor with adjustable warping angle achieved by screen printing greatly improves the detection sensitivity of the monitoring system to airflow;

[0023] 2. The manufacturing method based on screen printing technology realizes the integration of flexible circuit boards and sensors, improving the stability and ease of use of the monitoring system;

[0024] 3. It has the functions of monitoring nasal breathing airflow and temperature, providing an additional dimension of data for monitoring respiratory status, and improving the accuracy and functionality of respiratory monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a model of a respiratory monitoring system based on screen printing in the present invention.

[0026] Figure 2 It is a schematic diagram of the structure of the sensor in the present invention.

[0027] Figure 3 It is a schematic diagram of the structure of the sensor in the present invention before the sacrificial layer is removed.

[0028] Figure 4 The schematic diagram of the circuit of the respiratory monitoring system based on screen printing in the present invention.

[0029] Figure 5 It is a schematic diagram of the structural layering of the sensor in the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0031] This embodiment provides a respiratory monitoring system based on screen printing, such as Figure 1As shown, it is composed of a flexible circuit board 1, a sensor 2 and electronic components 3; wherein the sensor 2 includes: a strain sensor and a temperature sensor, and the strain sensor and the temperature sensor are prepared on the surface of the flexible circuit board 1 by a screen printing process; the electronic components 3 are mounted on the surface of the flexible circuit board 1, and the sensor 2 and each electronic component 3 are conductively interconnected through the flexible circuit board 1; the respiratory monitoring system is attached under the nostrils to monitor the nasal respiratory airflow.

[0032] Further, such as Figure 2 and Figure 3 As shown, the temperature sensor is a layer of temperature-sensitive material film 22 printed by screen printing, and the resistance value of the temperature-sensitive material film 22 will change with the ambient temperature, thereby realizing temperature sensing; the strain sensor adopts a cantilever beam structure with a free end bent upward, which is composed of a base 21, an elastic beam 25 and a strain electrode 24, and the strain electrode 24 is attached to the lower surface of the elastic beam 25, and the fixed end of the elastic beam 25 is fixed on the base 21, and the free end is naturally bent upward. When pushed by the nasal breathing airflow, the elastic beam 25 is bent and strained, so that the strain electrode 24 attached to its lower surface is deformed, and then the resistance value of the strain electrode 24 changes accordingly, thereby realizing strain sensing; the present invention creatively proposes to adopt screen printing The sensor 2 is prepared by the brush process, especially for the strain sensor. During the preparation process, a sacrificial layer with the same thickness as the base is first printed at the corresponding position of the elastic beam, and then the elastic beam 25 is printed on the surface of the sacrificial layer 23, and the fixed end is fixed to the surface of the base 21. By utilizing the difference in thermal expansion coefficients of the materials of the elastic beam 25 and the strain electrode 24, after removing the sacrificial layer 23, the free end of the elastic beam 25 is naturally warped upward to form a strain sensor with a cantilever beam structure with the free end warped upward; and by adjusting the material and shape of the elastic beam 25 and the strain electrode 24, the natural warping angle of the elastic beam 25 can be adjusted, thereby changing the sensitivity of the strain sensor to achieve a better monitoring effect on the airflow.

[0033] In a preferred embodiment, the strain electrode 24 is composed of two layers of different conductive materials, wherein the lower conductive material layer is a brittle conductive material layer 241 with a smaller resistance value, and the upper conductive material layer is an elastic conductive material layer 242 with a larger resistance value; when the elastic beam 25 is subjected to bending strain, the brittle conductive material 241 will break, causing the resistance value of the strain electrode 24 to increase sharply, thereby making the strain sensor have a higher sensitivity; if the bending degree of the elastic beam 25 continues to increase, the brittle conductive material 241 will completely break and there will be no conductive path, while the resistance value of the elastic conductive material 242 will only change slightly, so that the overall resistance value of the strain electrode 24 will slowly increase and will not suddenly change to infinity, thereby making the strain sensor have a larger dynamic range and linearity.

[0034] Further, such as Figure 4 As shown, the electronic components 3 are conductively interconnected through the flexible circuit board 1 to form a complete electronic system, which mainly includes all components and batteries that constitute the minimum system of the single-chip microcomputer; the electronic system has the functions of measuring the resistance value of the sensor, calculating and storing data, and communicating with other electronic systems such as the host computer; it should be noted that: the core innovation of the present invention is to propose a sensor 2 (strain sensor and temperature sensor) prepared on the flexible circuit board 1 based on the screen printing process, and the specific implementation process of the sensor and various electronic components together forming a respiratory monitoring system is a conventional technical means in the field, which will not be described in detail here.

[0035] This embodiment also provides a method for manufacturing the above-mentioned respiratory monitoring system based on screen printing, according to Figure 5 The hierarchical structure shown includes the following steps:

[0036] S1: Pre-processing a flexible circuit board 1 according to the conductive interconnection relationship between the sensor and various electronic components;

[0037] S2: Printing a graphic temperature-sensitive material film 22 on the surface of the flexible circuit board 1 by screen printing and curing, with both ends of the temperature-sensitive material film covering the surface of the reserved exposed electrodes of the flexible circuit board, and the thickness of the temperature-sensitive material film 22 is 5 to 20 μm;

[0038] S3: Printing the base 21 on the surface of the flexible circuit board 1 by screen printing and curing, printing again, curing, and repeating the overprinting multiple times to make the base thickness reach 50-100 μm;

[0039] S4: Printing a sacrificial layer 23 on the surface of the flexible circuit board 1 by screen printing, and performing multiple overprinting cycles to make the sacrificial layer have the same thickness as the base;

[0040] S5: Printing a graphic brittle conductive material layer 241 on the surface of the sacrificial layer 23 and the base 21 by screen printing and curing, and extending both ends of the brittle conductive material layer 241 to cover the surface of the reserved exposed electrode of the flexible circuit board; the thickness of the brittle conductive material layer 241 is 5-10 μm;

[0041] S6: printing an elastic conductive material layer 242 on the surface of the brittle conductive material layer 241 by screen printing and curing, the brittle conductive material layer 241 and the elastic conductive material layer 242 are stacked to form the strain electrode 24, and the thickness of the elastic conductive material layer 242 is 10-30 μm;

[0042] S7: printing the elastic beam 25 covering the strain electrode 24 on the surface of the sacrificial layer 23 and the base 21 by screen printing and curing, and performing multiple overprinting cycles to make the thickness of the elastic beam 25 reach 50-150 μm;

[0043] S8: placing the semi-finished device in warm water at 50-80° C. for ultrasonic cleaning for 10-30 minutes to remove the sacrificial layer 23, and then drying it in an environment at 100-150° C.;

[0044] S9: Mount the required electronic components 3 on the surface of the flexible circuit board 1 to form a respiratory monitoring system.

[0045] In a preferred embodiment, the temperature-sensitive material for screen printing can be a slurry with graphene or carbon nanotubes as the main material; the material used for the screen-printed base can be epoxy resin, acrylic resin or acrylic resin, etc.; the material used for the screen-printed sacrificial layer is a mixture of trimethylolethane, trimethylolpropane, cyclohexanol and propylene glycol; the brittle conductive material for screen printing can be conductive carbon paste, conductive copper paste or conductive silver paste; the elastic conductive material for screen printing adopts a mixture of conductive particles such as silver nanowires, carbon nanotubes, silver nanoparticles, carbon black and elastic resin materials, wherein the mass fraction of the conductive particles is between 5% and 15%; the material for the screen-printed elastic beam can be polydimethylsiloxane or silicone.

[0046] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A respiratory monitoring system based on screen printing, consisting of a flexible circuit board, a sensor and electronic components; characterized in that: The sensor includes: a strain sensor and a temperature sensor, which are prepared on the surface of a flexible circuit board through a screen printing process; the electronic components are mounted on the surface of the flexible circuit board, and the sensor and each electronic component are conductively interconnected through the flexible circuit board; the respiratory monitoring system is attached under the nostrils to monitor nasal respiratory airflow.

2. The screen-printed respiratory monitoring system according to claim 1, characterized in that: The temperature sensor is made of a temperature-sensitive material film, and the temperature-sensitive material film is printed on the surface of the flexible circuit board through a screen printing process.

3. The screen-printed respiratory monitoring system according to claim 1, characterized in that: The strain sensor adopts a cantilever beam structure, which consists of a base, a strain electrode and an elastic beam. The strain electrode is attached to the lower surface of the elastic beam, the fixed end of the elastic beam is fixed on the base, and the free end is naturally warped upward; the base, the strain electrode and the elastic beam are printed on the surface of the flexible circuit board in sequence through a screen printing process. During the printing process, a sacrificial layer is printed under the elastic beam, and the strain electrode and the elastic beam are printed on the sacrificial layer in sequence. After the sacrificial layer is removed, the free end of the elastic beam naturally warps upward to form a cantilever beam structure.

4. The screen-printed respiratory monitoring system according to claim 1, characterized in that: The strain electrode is composed of a brittle conductive material layer and an elastic conductive material layer. The elastic conductive material layer is located in the upper layer and attached to the lower surface of the elastic beam, and the brittle conductive material layer is located in the lower layer and attached to the lower surface of the elastic conductive material layer.

5. The screen-printed respiratory monitoring system according to claim 1, characterized in that: The electronic components mainly include all components and batteries that constitute the minimum system of the single-chip microcomputer.

6. The method for manufacturing a respiratory monitoring system based on screen printing according to claim 1, characterized in that: The following steps are involved: S1: Pre-processing a flexible circuit board according to the conductive interconnection relationship between the sensor and various electronic components; S2: Printing a graphic temperature-sensitive material film on the surface of the flexible circuit board by screen printing and curing, with both ends of the temperature-sensitive material film covering the surface of the reserved exposed electrodes of the flexible circuit board, and the thickness of the temperature-sensitive material film is 5 to 20 μm; S3: Printing the base on the surface of the flexible circuit board by screen printing and curing, printing again, curing, and repeating the overprinting multiple times to make the base thickness reach 50-100 μm; S4: Printing a sacrificial layer on the surface of the flexible circuit board by screen printing, and performing multiple overprinting cycles to make the sacrificial layer have the same thickness as the base; S5: Printing a graphic brittle conductive material layer on the surface of the sacrificial layer and the base by screen printing and curing, and extending both ends of the brittle conductive material layer to cover the surface of the reserved exposed electrode of the flexible circuit board; the thickness of the brittle conductive material layer is 5 to 10 μm; S6: printing an elastic conductive material layer on the surface of the brittle conductive material layer by screen printing and curing the layer, wherein the brittle conductive material layer and the elastic conductive material layer together constitute a strain electrode, and the thickness of the elastic conductive material layer is 10 to 30 μm; S7: printing an elastic beam covering the strain electrode on the surface of the sacrificial layer and the base by screen printing and curing, and performing multiple overprinting cycles to make the thickness of the elastic beam reach 50 to 150 μm; S8: placing the semi-finished device in warm water at 50 to 80° C. for ultrasonic cleaning for 10 to 30 minutes to remove the sacrificial layer, and then drying in an environment at 100 to 150° C.; S9: Mount the required electronic components on the surface of the flexible printed circuit board to form a respiratory monitoring system.

7. The method for manufacturing a respiratory monitoring system based on screen printing according to claim 6, characterized in that: In step S2, the temperature sensitive material is graphene or carbon nanotubes; in step S3, the base material is epoxy resin, acrylic resin or acrylic resin; in step S4, the sacrificial layer material is a mixture of trimethylolethane, trimethylolpropane, cyclohexanol and propylene glycol; in step S5, the brittle conductive material is conductive carbon paste, conductive copper paste or conductive silver paste; in step S6, the elastic conductive material is a mixture of conductive particles and elastic resin material, wherein the mass fraction of the conductive particles is between 5% and 15%; in step S7, the elastic beam material is polydimethylsiloxane or silica gel.

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