Three-way pulse sensing bracelet based on piezoresistive flexible sensor and manufacturing method

Abstract

The present invention discloses a three-way pulse sensing bracelet based on a piezoresistive flexible sensor and a manufacturing method. The present invention includes a sensor module and a bracelet layer, wherein the sensor module is embedded in the middle position of the end face of the bracelet layer; one end of the bracelet layer is processed into a T-shaped belt tail, and the other end of the bracelet layer is processed into a strip belt, and a plurality of strip holes distributed parallel to each other are spaced apart in the middle of the strip belt, and the strip holes are all parallel to the ends of the T-shaped belt tail, and the ends of the T-shaped belt tail are interference fit with the strip holes; a rectangular groove for placing the sensor module is processed in the middle position of the end face of the bracelet layer; the sensor module is mainly composed of an upper layer of the sensor module and a lower layer of the sensor module superimposed from top to bottom, and the sawtooth structure of the upper layer of the sensor module corresponds to the three pulses of the human body, namely, Cun, Guan, and Chi, respectively, and the electrode layer and the sensor unit coated on the lower layer of the sensor module are used to collect human pulse information. The present invention has good sensitivity and stability, and is conducive to the objectification and standardization of pulse diagnosis in traditional Chinese medicine.

Description

Technical Field

[0001] The invention relates to a three-way pulse sensing bracelet in the field of sensing bracelets and a manufacturing method thereof, and in particular to a three-way pulse sensing bracelet based on a piezoresistive flexible sensor and a manufacturing method thereof. Background Art

[0002] The radial artery pressure wave is composed of three waves: a forward wave generated by the proximal end of the aorta and two reflected waves, which are waves that arrive later in the hand area and the lower body. The peak value P1 at the end of the ascending branch and the peak value of the reflected wave in the lower body minus the end-diastolic pressure P2, P2 / P1 is used as the radial artery enhancement index AIr. ΔTDVP is the time difference between the P1 peak and the P2 peak in one cardiac cycle, which is used as an indicator to measure arterial stiffness.

[0003] The radial artery pressure waveform can provide valuable information for the diagnosis and treatment of cardiovascular diseases, such as arteriosclerosis, hypertension, arrhythmia, atrial fibrillation, etc. Many hemodynamic parameters, such as arteriosclerosis index, stroke time, stroke volume change and cardiac output can be calculated and estimated in real time directly from the pressure waveform. As elastic arteries become stiffer, the pulse wave velocity increases, and the reflected wave from the lower body returns to the radial artery earlier, resulting in a decrease in ΔTDVP and an increase in AIr, thereby estimating arterial stiffness.

[0004] In addition, by taking the derivative of the pulse wave in the time domain, the sudden changes and time shifts of the waveform can be accurately analyzed to distinguish between healthy people and patients with arteriosclerosis.

[0005] Physicians have a long history of assessing health conditions by checking human pulse waves. Among them, Chinese medicine pulse diagnosis is a method of inferring the "progress and regression prognosis" of a disease by pressing the three pulses of the human body, namely, Cun, Guan, and Chi, with different intensities in clinical practice through the three steps of lifting, pressing, and searching. It is an important part of the diagnosis and treatment process of Chinese medicine dialectical treatment. However, today, there is a lack of designs that combine Chinese medicine pulse diagnosis with pulse detection equipment, which will help modernize, intelligentize, and normalize traditional Chinese medicine. Embedding flexible pressure sensors in wrist wearable devices to obtain pulse wave signals in a long-term and stable manner can play an important auxiliary role in Chinese medicine pulse diagnosis.

[0006] Currently, there are a series of sensors such as optical, acoustic, and mechanical. Among them, optical sensors occupy a major share in the market, and pressure transducers are less used. In terms of mechanical sensors, there are piezoresistive, piezoelectric, capacitive, transistor, and triboelectric types. Among them, the piezoresistive structure is widely used, simple in design, and highly sensitive. However, it is affected by the inherent viscoelasticity of polymer-based composite materials, and the sensors generally have hysteresis and slow time response; and the electrical characteristics are greatly affected by temperature. At present. Piezoresistive pressure sensors are mainly made of copper cladding and polyimide. The Young's modulus of the material is large, which cannot meet the requirements of high flexibility and cannot meet the requirements of close fit to human skin. Summary of the invention

[0007] In order to meet the requirements of modernization and standardization of traditional Chinese medicine and overcome the shortcomings of the above-mentioned prior art, the present invention provides a three-way pulse sensing bracelet based on a piezoresistive flexible sensor and a manufacturing method. The present invention uses the sawtooth structure of the upper layer of the sensor module to correspond to the three pulses of the human body, namely, the cun, guan, and chi. The electrode layer and the piezoresistive flexible sensing unit coated on the lower layer of the sensor module are used to collect human pulse information. The present invention has good sensitivity and stability, which is conducive to the objectification and standardization of traditional Chinese medicine pulse diagnosis.

[0008] The technical solution adopted by the present invention is:

[0009] 1. A three-way pulse sensing bracelet based on piezoresistive flexible sensor

[0010] The present invention comprises a sensor module and a wristband layer, wherein the sensor module is embedded in the middle position of the end face of the wristband layer; one end of the wristband layer is processed into a T-shaped belt tail, and the other end of the wristband layer is processed into a strip belt, and a plurality of strip holes distributed parallel to each other are arranged at intervals in the middle of the strip belt, and the strip holes are all parallel to the ends of the T-shaped belt tail, and the ends of the T-shaped belt tail are interference-fitted with the strip holes; a rectangular groove for placing the sensor module is processed in the middle position of the end face of the wristband layer, and a rectangular gap is opened at a position of the wristband layer close to the T-shaped belt tail, and the rectangular gap is perpendicular to the strip holes; the sensor module is mainly composed of an upper sensor module layer and a lower sensor module layer stacked from top to bottom.

[0011] The top surface of the upper layer of the sensor module is provided with three small rectangular grooves which are parallel to each other and of different sizes, and each small rectangular groove of the upper layer of the sensor module is processed with an upper sawtooth structure, and the upper layer of the sensor module contacts three pulses of the human body through the upper sawtooth structure;

[0012] The upper surface of the lower layer of the sensing module is coated with an electrode layer and a piezoresistive flexible sensing unit, and the electrode layer is electrically connected to the piezoresistive flexible sensing unit; the electrode layer mainly includes four electrode groups, each electrode group includes a straight portion of an electrode line and a wavy portion of an electrode line, and the straight portions of the electrode lines of the four electrode groups are respectively a first wire, a second wire, a third wire and a fourth wire, and the piezoresistive flexible sensing unit is mainly composed of a first equivalent resistor R1, a second equivalent resistor R2 and a third equivalent resistor R3 in parallel, one end of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are simultaneously connected to the wavy portion of the electrode line of one electrode group of the electrode layer and then connected to the third wire of the electrode layer through the electrode line, the other ends of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are respectively connected to the first wire, the second wire and the fourth wire through the wavy portion of the electrode line of the remaining three electrode groups, and finally the first wire, the second wire, the third wire and the fourth wire are simultaneously connected to the FPC connection end, and then connected to the signal acquisition circuit board through the FPC connector.

[0013] Each of the upper sawtooth structures is mainly formed by N sawtooths parallel to the strip holes, and each sawtooth is mainly composed of a sawtooth tip and a sawtooth base matched from top to bottom, and the sawtooth base is tightly bonded to the upper layer of the sensor module; the lengths of the three upper sawtooth structures are different, and correspond to three acupuncture points of the human body respectively, and the two side surfaces of the sawtooth tip are processed into inclined surfaces.

[0014] The four corners of the end of the T-shaped belt tail are rounded.

[0015] Two circular holes for positioning are arranged at intervals at the bottom of the rectangular groove near the strip hole.

[0016] The equivalent resistance of the piezoresistive flexible sensing unit is S-shaped, and the sensitive material wiring of the piezoresistive flexible sensing unit is wavy.

[0017] The transverse electrodes of the electrode layer are designed to be wavy, and the longitudinal electrodes of the electrode layer facing the same part as the radial artery of the human body are designed to be straight.

[0018] 2. Manufacturing method of sensor bracelet

[0019] The manufacturing method specifically comprises the following steps:

[0020] 1) Manufacturing molds and screen printing plates for the bracelet layer, the upper layer of the sensor module, the lower layer of the sensor module, the upper sawtooth structure, the electrode layer and the piezoresistive flexible sensor unit;

[0021] 2) The raw materials corresponding to each component are mixed and configured respectively, wherein the raw materials include polydimethylsiloxane PDMS liquid material, curing agent, graphene, nano silver flakes, silicone rubber, polyphenylmethylsiloxane, zinc oxide and tetrahydrofuran; the configured mixed solution is then degassed after centrifugal stirring, and the degassed mixed solution is then scraped and filled into the mold or screen printing plate corresponding to each component, and finally heated and cured to complete the manufacture of the bracelet layer, the upper layer of the sensor module, the lower layer of the sensor module, the upper sawtooth structure, the electrode layer and the piezoresistive flexible sensor unit;

[0022] 3) Encapsulate the sensor module and the bracelet layer to complete the manufacturing of the sensing bracelet.

[0023] The wristband layer, the upper sawtooth structure and the lower layer of the sensor module are mainly made of hardened polydimethylsiloxane (PDMS) mixed material, and the hardened PDMS mixed material is mainly formed by mixing polydimethylsiloxane (PDMS) liquid material, 10% silicone rubber-based curing agent and 5% silicone rubber-based nano-silicon dioxide powder in a mass ratio of 20:2:1;

[0024] The upper layer of the sensor module is mainly formed by mixing polydimethylsiloxane PDMS liquid material and curing agent in a mass ratio of 10:1;

[0025] The electrode layer is made of graphene GR / silver nanosheets AgNF / silicon rubber SR nanocomposite material, wherein the graphene GR / silver nanosheets AgNF / silicon rubber SR nanocomposite material is mainly formed by mixing silicone rubber, AgNF, graphene GR, polyvinyl pyrrolidone PVP, and tetrahydrofuran in a mass ratio of 100:66:4:1:100;

[0026] The piezoresistive flexible sensing unit is made of another nanocomposite material, which is mainly made of silicone rubber SR, foaming agent, graphene GR, silver nanosheets AgNF, ZnO, and polydimethylsiloxane PPMS in a mass ratio of 100:5:4:49:3:100.

[0027] The screen printing plate is a metal mask plate processed by laser cutting technology.

[0028] The beneficial effects of the present invention are:

[0029] (1) The present invention is closely combined with traditional Chinese medicine pulse diagnosis to assist doctors in realizing the scientific and concrete nature of the three parts and nine lords.

[0030] (2) The present invention has good flexibility, and can adapt to the radial styloid process on the periphery of the wrist by designing a rectangular gap, and can adjust the tightness by designing multiple holes to fit the upper layer tightly to the skin. In addition, the polydimethylsiloxane material has certain flexibility, elasticity, and skin-friendliness, which greatly improves the comfort of the bracelet layer when worn.

[0031] (3) In order to meet the detection requirements within the low pressure range below 10kPa generated by pulse pulsation and the detection requirements after the wrist is tied and pressure is applied, the detection range of the sensor unit has been improved. The detection area with a higher single sensor unit can clearly sense more than 3 times the width of the radial artery pulsation pressure, which increases the sensing detection range and the tolerance of the wearing position. The influence of temperature changes on the sensor unit and the electrode can be ignored. In addition, the application of the sawtooth structure also reduces the pressure area of ​​the sensitive element while increasing the local strain; the axial direction of the wrist can reduce the cross-sectional area of ​​the current path when under pressure, further increasing the trend of increasing resistance.

[0032] (4) Sensors based on two-dimensional graphene films can only withstand tensile deformation but not compressive deformation. Sensors based on three-dimensional graphene can expand and contract in both horizontal and vertical directions when subjected to external forces, and can withstand greater pressure and strain. Therefore, the present invention uses three-dimensional graphene and distributes it in a wavy shape, so that the electrode is not easily broken when subjected to tension.

[0033] (5) It has better stability, faster response characteristics, lower hysteresis, and better repeatability.

[0034] (6) It has good durability. By making the bracelet layer and the sensor module separately and designing a tight fit, when the sensor module is damaged, it can be partially remade, reducing material waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a three-dimensional diagram of the layered structure of the perception bracelet in the present invention;

[0036] Figure 2 It is a plan view of the sawtooth structure of the present invention;

[0037] Figure 3 It is a single sawtooth structure diagram of the present invention;

[0038] Figure 4 is a plan view of the electrode layer of the present invention;

[0039] Figure 5 is a dimensional diagram of a single sensing unit of the present invention;

[0040] Figure 6 is a schematic diagram of a screen printing plate of a sensitive material of the present invention;

[0041] Figure 7 is a schematic diagram of a screen printing plate of an electrode layer of the present invention;

[0042] Figure 8 It is a schematic diagram of the manufacturing process of the present invention;

[0043] Fig. 9 is an equivalent circuit diagram of the sensing unit of the present invention;

[0044] Fig.10 It is a dimension diagram of the wristband layer of the present invention;

[0045] Fig.11 It is the principle diagram of the information collection working circuit of the present invention;

[0046] Fig.12 is a sensitivity curve diagram of a sensing unit in one embodiment of the present invention;

[0047] Fig.13 is a graph of relative resistance changes of a sensing unit under load cycles of different amplitudes in one embodiment of the present invention;

[0048] Fig.14 is a schematic diagram of a resistance-normalized pulse wave in which a sensor unit removes signal fluctuations caused by wrist movement in one embodiment of the present invention;

[0049] Fig.15 Yes Select Fig.14 Waveform diagram of a single cycle pulse wave.

[0050] As shown in the figure: 1-rectangular depression, 2-upper sawtooth structure, 3-upper layer of sensor module, 4-piezoresistive flexible sensor unit, 5-lower layer of sensor module, 6-electrode layer, 7-first sawtooth, 8-second sawtooth, 9-third sawtooth, 13-T-shaped tail, 14-rectangular gap, 15-strip hole, 16-sawtooth tip, 17-sawtooth base, 18-straight part of electrode line, 19-electrode line. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] like Figure 1As shown, the sensing bracelet includes a sensor module and a bracelet layer, and the sensor module is embedded in the middle position of the end face of the bracelet layer; one end of the bracelet layer is processed into a T-shaped belt tail 13, and the other end of the bracelet layer is processed into a strip belt, and six strip holes 15 distributed parallel to each other are spaced apart in the middle of the strip belt, and the strip holes 15 are all parallel to the ends of the T-shaped belt tail 13, and the ends of the T-shaped belt tail 13 are interference fit with the strip holes 15, that is, the width and length of the ends of the T-shaped belt tail 13 are respectively greater than the width and length of the strip holes 15; a rectangular groove 1 for placing the sensor module is processed in the middle position of the end face of the bracelet layer, and a rectangular gap 14 is opened at the position of the bracelet layer near the T-shaped belt tail 13, and the rectangular gap 14 is perpendicular to the strip hole 15 to adapt to the radial styloid process and improve the close fit between the bracelet layer and the skin; the sensor module is mainly composed of a sensor module upper layer 3 and a sensor module lower layer 5 stacked from top to bottom.

[0053] The top surface of the upper layer 3 of the sensor module is provided with three small rectangular grooves which are parallel to each other and of different sizes, and each small rectangular groove of the upper layer 3 of the sensor module is processed with an upper sawtooth structure 2, and the upper layer 3 of the sensor module contacts the three pulses of the human body through the upper sawtooth structure 2;

[0054] like Figure 4-7 As shown, the upper surface of the lower layer 5 of the sensing module is coated with an electrode layer 6 and a piezoresistive flexible sensing unit 4, and the electrode layer 6 is electrically connected to the piezoresistive flexible sensing unit 4; the electrode layer 6 mainly includes four electrode groups, each of which includes an electrode line straight line portion 18 and an electrode line wavy line portion, and the electrode line straight line portions 18 of the four electrode groups are respectively a first wire, a second wire, a third wire and a fourth wire, as shown in FIG. Fig. 9 As shown, the piezoresistive flexible sensing unit 4 is mainly composed of a first equivalent resistor R1, a second equivalent resistor R2 and a third equivalent resistor R3 in parallel. One ends of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are simultaneously connected to the wavy line portion of the electrode line of a group of electrode groups of the electrode layer 6 and then connected to the third wire of the electrode layer 6 through the electrode line 19. The other ends of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are respectively connected to the first wire, the second wire and the fourth wire through the wavy line portion of the electrode line of the remaining three groups of electrode groups. Finally, the first wire, the second wire, the third wire and the fourth wire are simultaneously connected to the FPC connection end, and then connected to the signal acquisition circuit board through the FPC connector.

[0055] like Figure 2 and Figure 3As shown, each upper sawtooth structure 2 is mainly formed by six sawtooths parallel to the strip hole 15, and each sawtooth is mainly composed of a sawtooth tip 16 and a sawtooth base 17 matched from top to bottom, and the sawtooth base 17 is tightly bonded to the upper layer 3 of the sensor module. Specifically, the three upper sawtooth structures 2 are respectively the first sawtooth 7, the second sawtooth 8 and the third sawtooth 9; the lengths of the three upper sawtooth structures 2 are different, and correspond to three acupuncture points of the human body, namely Cun, Guan and Chi, and the lengths of the three acupuncture points are different, which are approximately 1.5 cm, 0.75 cm and 2.5 cm respectively; in order to facilitate demoulding, the two side surfaces of the sawtooth tip 16 are processed into bevels.

[0056] The four corners of the end of the T-shaped belt tail 13 are rounded, and the size of the T-shaped belt tail 13 is 10mm×30mm. When worn, it is inserted into the hole from the outside to the inside; the width of the M strip holes 15 is 4mm, and the spacing between every two adjacent strip holes 15 is 8mm. The adjustment range of the bracelet layer is 48mm, which is suitable for most adults and children; the width of the rectangular groove 1 is 54mm, and the length of the rectangular groove 1 is 45mm, which is similar to the total length of the three acupoints of Cun, Guan, and Chi. Specifically, due to the difference in arm length and body length of the human body, the lengths of the three acupoints of Cun, Guan, and Chi are not exactly the same. Among them, Guan is 0.75cm near the styloid process of the ulna of the human body, Cun is 1.5cm towards the palm of the human body, and Chi is 2.5cm towards the palm of the human body. The specific length varies from person to person.

[0057] Two circular holes with a diameter of 3 mm are provided at intervals at the bottom of the rectangular groove 1 near the strip hole 15 for positioning.

[0058] The equivalent resistance of the piezoresistive flexible sensing unit 4 is S-shaped, and the sensitive material wiring of the piezoresistive flexible sensing unit 4 is wavy.

[0059] The transverse electrodes of the electrode layer 6 are designed to be wavy, and the longitudinal electrodes of the electrode layer 6 that face the same part as the radial artery of the human body are designed to be straight.

[0060] like Figure 8 As shown, the manufacturing method specifically includes the following steps:

[0061] 1) manufacturing a mold and a screen printing plate for a wristband layer, an upper layer 3 of a sensor module, a lower layer 5 of a sensor module, an upper sawtooth structure 2, an electrode layer 6 and a piezoresistive flexible sensor unit 4;

[0062] The mold is a mold with patterned grooves for each component, which is manufactured using 3D printing technology. The printing material uses 8000 type white photosensitive resin to obtain higher precision. The mold is placed in anhydrous ethanol and ultrasonically treated for 15 minutes. After removing the mold, the release agent is evenly sprayed in the groove and left to stand at room temperature.

[0063] 2) The raw materials corresponding to each component are mixed and configured respectively, and the raw materials include polydimethylsiloxane PDMS liquid material, curing agent, graphene, nano silver flakes, silicone rubber, polyphenylmethylsiloxane, zinc oxide and tetrahydrofuran; the configured mixed solution is then centrifuged and stirred for 3 minutes and then degassed for 1 minute, and then the degassed mixed solution is scraped and filled into the mold or screen printing plate corresponding to each component, and finally heated and cured at a temperature of 90° C. to complete the manufacture of the bracelet layer, the upper layer 3 of the sensor module, the lower layer 5 of the sensor module, the upper sawtooth structure 2, the electrode layer 6 and the piezoresistive flexible sensor unit 4;

[0064] 3) Encapsulate the sensor module and the bracelet layer to complete the manufacturing of the sensing bracelet.

[0065] Specifically, the edge portion where the upper layer 3 of the sensor module is combined with the lower layer 5 of the sensor module and the edge portion where the sensor module is combined with the bracelet layer are coated with a polydimethylsiloxane (PDMS) mixed material for packaging. Finally, the entire sensing bracelet is placed in an ascorbic acid solution and heated to complete the manufacturing of the sensing bracelet layer.

[0066] The wristband layer, the upper sawtooth structure 2 and the lower layer 5 of the sensor module are mainly made of hardened polydimethylsiloxane PDMS mixed material, and the hardened polydimethylsiloxane PDMS mixed material is mainly formed by mixing polydimethylsiloxane PDMS liquid material, a curing agent mixed with 10% of silicone rubber base and nano-silicon dioxide powder mixed with 5% of silicone rubber base in a mass ratio of 20:2:1;

[0067] The upper layer 3 of the sensor module is mainly formed by mixing polydimethylsiloxane PDMS liquid material and curing agent in a mass ratio of 10:1;

[0068] The electrode layer 6 is made of a graphene GR / silver nanosheet AgNF / silicon rubber SR nanocomposite material, wherein the graphene GR / silver nanosheet AgNF / silicon rubber SR nanocomposite material is mainly formed by mixing silicone rubber, AgNF, graphene GR, polyvinyl pyrrolidone PVP, and tetrahydrofuran in a mass ratio of 100:66:4:1:100;

[0069] Among them, the piezoresistive flexible sensing unit 4 is made of another nano-composite material, which is mainly made of silicone rubber SR, foaming agent, graphene GR, silver nanosheets AgNF, ZnO, and polydimethylsiloxane PPMS in a mass ratio of 100:5:4:49:3:100.

[0070] Preferably, the screen printing plate is a metal mask plate processed by laser cutting technology.

[0071] In one embodiment of the present invention, Fig.11 As shown, initially, the analog switches connecting the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are disconnected. At the beginning of scanning, the digital signal processor controls the analog switch connected to the common line to be always closed, and the analog switch connected to the first equivalent resistor R1 is closed. The equivalent resistance of the sensing unit is in the megohm level. After the voltage is amplified by the operational amplifier, the analog-to-digital conversion module of the digital signal processor converts the analog signal into a digital signal, and then the serial communication receiving interface transmits the signal to the host computer. After that, the analog switch connected to the first equivalent resistor R1 is disconnected, and the analog switch connected to the second equivalent resistor R2 is closed. The voltage signal is amplified and transmitted to the host computer after analog-to-digital conversion. According to the above process cycle, the signals from the three sensors are continuously scanned. The maximum main frequency of the digital signal processor is 150MHz, which can complete 32×32-bit multiplication in 1 cycle.

[0072] In one embodiment of the present invention, Fig.12 As shown, the sensitivity of the sensing bracelet layer was measured using a dynamic magnetic multi-dimensional dynamic precision loading platform and a desktop digital multimeter. The linear relationship between the relative resistance ΔR / R0 and the pressure was good, and the sensitivity was about 0.18 kPa. -1 .

[0073] In one embodiment of the present invention, Fig.13 As shown, in the upper computer operation interface of the dynamic magnetic multi-dimensional dynamic precision loading platform, the waveform of the loading head displacement is set to a triangular wave, the loading frequency is 1Hz, and the pressure peaks of 5kPa, 10kPa, and 15kPa are applied to the sensor unit in sequence. Each group of cyclic loads with the same pressure is loaded for 5 cycles, and the interval for loading pressures with different pressure peaks is 1s. The peak value of the relative resistance ΔR / R0 obtained is proportional to the pressure peak value, which is consistent with the sensitivity calibration data.

[0074] In one embodiment of the present invention, Fig.14 As shown, the filter type is set to a 70-order low-pass FIR filter with a cutoff frequency of 4 Hz to filter out high-frequency noise interference, process and normalize. The subject's pulse fluctuates 32 times in 27 seconds, and the heart rate can be calculated to be 71 bpm, which is within the normal heart rate range for adults at rest. Select Fig.14 The fifth cardiac cycle is analyzed. Fig.15 As shown, the arterial stiffness index AIr = P2 / P1 = 0.35. The subject's height h = 1.73m, the arterial stiffness measurement index ΔTDVP = 0.33s, so the arterial stiffness index SI = h / ΔTDVP = 5.24, the subject is 22 years old, and the arterial stiffness index is within the normal range corresponding to this age group.

[0075] like Fig.10 As shown, the parameters of the wristband layer and the sensor module in the embodiment of the present invention are as follows:

[0076] The dimensions of the upper layer 3 of the sensor module and the lower layer 5 of the sensor module are both 53mm×72mm×3mm. The distance from the top of the upper layer 3 of the sensor module to the boss with the sawtooth depression is 0.6mm, and the distance from the boss of the sawtooth to the bottom of the concave part is 1.2mm. The part of the lower layer 5 of the sensor module that contacts the electrode smoothly transitions from a depth of 0.8mm to 0.3mm. The overall dimensions of the bracelet layer are 312mm×65mm×3mm. The thickness of the overall bracelet layer is 2mm, the total width is 54mm, and the total length is 300mm. The thickness of the rectangular groove 1 is 1.2mm, the length is 45mm, and the width is 54mm. The diameter of the two circular holes in the rectangular groove 1 that play a positioning role is 3mm. The gap between the six long openings at 40mm on the left side of the rectangular groove 1 is 4mm, and each opening is 8mm apart. The rectangular gap on the right side of the rectangular groove 1 is 36mm long and 18mm wide, leaving 4 fillets with a radius of 6mm. The total thickness of the upper layer 3 of the sensing module is 1mm, the bottom length of the row of sawtooth corresponding to inches is 11.50mm, and the upper edge length is 8.50mm; the length of the row corresponding to switches is 7.50mm, and the upper edge length is 4.50mm; the length of the row corresponding to rulers is 18.00mm, and the upper edge length is 15.00mm. The distance between each row is 4.00mm. The distance between each row of sawtooth is 1.50mm, and the vertical thickness of a single sawtooth is 1.30mm, of which the bottom rectangle is 0.10mm thick and 1.50mm wide. The thickness of the lower layer 5 of the sensing module is 0.80mm, and the thickness of the electrode layer 6 is 0.10mm, and the width is about 0.50mm. The thickness of the piezoresistive flexible sensing unit 4 is 0.50mm, and the distances between the sensitive materials corresponding to inches, switches, and rulers are 6.50mm and 9.75mm, respectively. Figure 5 As shown, the wavy arc has an angle of 60° and a radius of 1.00 mm, and the wavy shape of the electrode layer is the same as that of the sensitive material.

[0077] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A three-way pulse sensing bracelet based on a piezoresistive flexible sensor, characterized in that: It comprises a sensor module and a wristband layer, wherein the sensor module is embedded in the middle of the end surface of the wristband layer; one end of the wristband layer is processed into a T-shaped belt tail (13), The other end of the bracelet layer is processed into a strip, and a plurality of strip holes (15) are arranged in parallel in the middle of the strip, and the strip holes (15) are parallel to the ends of the T-shaped belt tail (13), and the ends of the T-shaped belt tail (13) are interference fit with the strip holes (15); A rectangular groove (1) for placing a sensor module is processed in the middle of the end surface of the wristband layer, and a rectangular gap (14) is opened at a position of the wristband layer close to the T-shaped belt tail (13), and the rectangular gap (14) is perpendicular to the strip hole (15); the sensor module is mainly composed of a sensor module upper layer (3) and a sensor module lower layer (5) stacked from top to bottom; The top surface of the upper layer (3) of the sensor module is provided with three small rectangular grooves which are parallel to each other and of different sizes, and each small rectangular groove of the upper layer (3) of the sensor module is processed with an upper layer sawtooth structure (2), and the upper layer (3) of the sensor module is in contact with three pulses of the human body through the upper layer sawtooth structure (2); The upper surface of the lower layer (5) of the sensing module is coated with an electrode layer (6) and a piezoresistive flexible sensing unit (4), and the electrode layer (6) is electrically connected to the piezoresistive flexible sensing unit (4); The electrode layer (6) mainly comprises four groups of electrode groups, each of which comprises a straight electrode line portion (18) and a wavy electrode line portion, and the straight electrode line portions (18) of the four groups of electrode groups are respectively a first wire, a second wire, a third wire and a fourth wire, and the piezoresistive flexible sensing unit (4) mainly comprises a first equivalent resistor R1, a second equivalent resistor R2 and a third equivalent resistor R3 connected in parallel, one end of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are simultaneously connected to the wavy electrode line portion of one group of electrode groups in the electrode layer (6) and then connected to the third wire of the electrode layer (6) through the electrode line (19), and the other ends of the first equivalent resistor R1, the second equivalent resistor R2 and the third equivalent resistor R3 are respectively connected to the first wire, the second wire and the fourth wire through the wavy electrode line portions of the remaining three groups of electrode groups, and finally the first wire, the second wire, the third wire and the fourth wire are simultaneously connected to the FPC connection end, and then connected to the signal acquisition circuit board through the FPC connector; Each of the upper sawtooth structures (2) is mainly formed by N sawtooths parallel to the strip-shaped hole (15), and each sawtooth is mainly composed of a sawtooth tip (16) and a sawtooth base (17) matched from top to bottom, and the sawtooth base (17) is tightly bonded to the upper layer (3) of the sensor module; the lengths of the three upper sawtooth structures (2) are different, and correspond to three acupuncture points of the human body respectively, and both side surfaces of the sawtooth tip (16) are processed into inclined surfaces.

2. A three-way pulse sensing bracelet based on a piezoresistive flexible sensor according to claim 1, characterized in that: The four corners of the end of the T-shaped belt tail (13) are rounded.

3. A three-way pulse sensing bracelet based on a piezoresistive flexible sensor according to claim 1, characterized in that: Two circular holes for positioning are arranged at intervals at the bottom of the rectangular groove (1) near the strip hole (15).

4. The three-way pulse sensing bracelet based on piezoresistive flexible sensor according to claim 1, characterized in that: The equivalent resistance of the piezoresistive flexible sensing unit (4) is S-shaped, and the sensitive material wiring used to make the piezoresistive flexible sensing unit (4) is wavy.

5. The three-way pulse sensing bracelet based on piezoresistive flexible sensor according to claim 1, characterized in that: The transverse electrodes of the electrode layer (6) are designed to be wavy, and the longitudinal electrodes of the electrode layer (6) facing the same part as the radial artery of the human body are designed to be straight.

6. The manufacturing method of the sensor bracelet according to any one of claims 1 to 5, characterized in that: The manufacturing method specifically comprises the following steps: 1) manufacturing a mold and a screen printing plate for a wristband layer, an upper layer of a sensor module (3), a lower layer of a sensor module (5), an upper sawtooth structure (2), an electrode layer (6) and a piezoresistive flexible sensor unit (4); 2) The raw materials corresponding to each component are mixed and configured respectively, wherein the raw materials include polydimethylsiloxane (PDMS) liquid material, a curing agent, graphene, nanosilver flakes, silicone rubber, polyphenylmethylsiloxane, zinc oxide and tetrahydrofuran; the configured mixed solutions are then centrifuged and stirred for degassing, and the degassed mixed solutions are then scraped and filled into molds or screen printing plates corresponding to each component, and finally heated and cured to form, thereby completing the manufacture of the wristband layer, the upper layer of the sensor module (3), the lower layer of the sensor module (5), the upper sawtooth structure (2), the electrode layer (6) and the piezoresistive flexible sensor unit (4); 3) Encapsulate the sensor module and the bracelet layer to complete the manufacturing of the sensing bracelet.

7. The manufacturing method of the sensory bracelet according to claim 6, characterized in that: The wristband layer, the upper sawtooth structure (2) and the lower layer (5) of the sensor module are mainly made of a hardened polydimethylsiloxane (PDMS) mixed material, wherein the hardened PDMS mixed material is mainly formed by mixing a polydimethylsiloxane (PDMS) liquid material, a curing agent mixed with 10% of a silicone rubber base and a nano-silicon dioxide powder mixed with 5% of a silicone rubber base in a mass ratio of 20:2:1; The upper layer (3) of the sensor module is mainly formed by mixing a polydimethylsiloxane (PDMS) liquid material and a curing agent in a mass ratio of 10:1; The electrode layer (6) is made of a graphene GR / silver nanosheet AgNF / silicon rubber SR nanocomposite material, wherein the graphene GR / silver nanosheet AgNF / silicon rubber SR nanocomposite material is mainly formed by mixing silicone rubber, AgNF, graphene GR, polyvinyl pyrrolidone PVP, and tetrahydrofuran in a mass ratio of 100:66:4:1:100; The piezoresistive flexible sensing unit (4) is made of another nanocomposite material, wherein the other nanocomposite material is mainly made by mixing silicone rubber SR, foaming agent, graphene GR, silver nanosheets AgNF, ZnO, and polydimethylsiloxane PPMS in a mass ratio of 100:5:4:49:3:

100.

8. The manufacturing method of the sensory bracelet according to claim 7, characterized in that: The screen printing plate is a metal mask plate processed by laser cutting technology.

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