Blood pressure monitoring sensor and method of manufacturing the same

Abstract

The application provides a blood pressure monitoring sensor and a preparation method thereof. The blood pressure monitoring sensor comprises at least: a liquid drop sensitization module for transmitting an arterial pulse signal; a pressure sensing module for generating an electric signal according to the arterial pulse signal, wherein the pressure sensing module comprises a polymer optical fiber probe which can be deformed according to the arterial pulse signal; and a signal processing module for extracting a cardiovascular characteristic parameter according to the electric signal to obtain a blood pressure value. The blood pressure monitoring sensor provided by the application has high sensitivity, is wearable, and can be used to monitor blood pressure in real time in daily life without the operation of professionals.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wearable smart devices, in particular to a blood pressure monitoring sensor and a preparation method thereof. BACKGROUND

[0002] Traditional blood pressure monitoring adopts auscultation method, and uses a cuff-type sphygmomanometer to measure blood pressure, which needs to be operated by a professional person. The cuff-type sphygmomanometer is not portable and cannot be worn in real time, and cannot meet the demand of continuous measurement of blood pressure, and cannot track the blood pressure change of a cardiovascular disease patient in real time all day long, and cannot effectively prevent sudden cardiovascular diseases.

[0003] In order to realize all-day real-time monitoring of blood pressure, a blood pressure monitoring bracelet with a point-type, line-type pressure resistance type pressure sensor is usually used for blood pressure monitoring. However, the alignment requirement of the position of such a sensor and the pulse beat area is relatively harsh, the preparation method and preparation process are complex, and batch production is difficult to realize. The ordinary pressure sensor scheme requires that the pressure sensor be placed at a position where arterial pulsation is obvious to capture a pulse waveform, and the measurement position requirement is harsh, the sensing area is small, the measurement posture is limited, and the sensitivity is low.

[0004] At present, a wearable sensor technology is urgently needed, which does not need to be operated by a professional person and can track the blood pressure change of a cardiovascular disease patient in real time all day long, so as to better realize all-day real-time accurate monitoring of blood pressure. SUMMARY

[0005] In order to solve the above problems, the embodiments of the present application provide a blood pressure monitoring sensor and a preparation method thereof, and a blood pressure monitoring method and a corresponding device.

[0006] In a first aspect, the present application provides a blood pressure monitoring sensor, at least comprising: a liquid drop sensitization module for transmitting an arterial pulse signal; a pressure sensing module for generating an electric signal according to the arterial pulse signal, the pressure sensing module comprising a polymer optical fiber probe, the polymer optical fiber probe being deformable according to the arterial pulse signal; and a signal processing module for extracting a cardiovascular characteristic parameter according to the electric signal to obtain a blood pressure value. Thus, the blood pressure monitoring sensor provided by the present application has high sensitivity, is wearable, and can monitor blood pressure in real time in daily life without the need for a professional person to operate.

[0007] As a feasible embodiment, the polymer optical fiber probe comprises: an input end including a first optical fiber; an output end including a second optical fiber; and a polymer tube that forms a closed cavity with the input and output ends, wherein the core of the first optical fiber is disconnected from the core of the second optical fiber within the closed cavity. As a result, when light propagates through the optical fiber into the polymer tube, a portion of the reflected and refracted light radiates from the hollow polymer tube into the environment. Arterial pulse signals cause the polymer tube to bend and deform, resulting in optical power leakage. The greater the deformation of the elastic hollow polymer tube, the more light is lost. Using this polymer optical fiber probe to detect light intensity, the response time of the blood pressure monitoring sensor is within 10ms, with no hysteresis effect, meeting real-time monitoring requirements.

[0008] As a feasible embodiment, the pressure sensing module further includes a light transmitting unit and a light receiving unit; the light transmitting unit is connected to the first optical fiber and is configured to transmit a first optical signal; the polymer optical fiber probe is configured to generate a second optical signal based on the first optical signal and the arterial pulse signal; and the light receiving unit is connected to the second optical fiber and is configured to generate the electrical signal based on the second optical signal. This allows detection of light intensity transmission loss within the structure due to refraction and reflection of incident light, or bending or squeezing of the flexible polymer tube. By measuring the light intensity output from the optical fiber at the receiving end, microscale pressure signal changes can be measured, i.e., pressure signal changes can be measured by modulating the transmitted light with the pulse micropressure signal.

[0009] As a feasible implementation, the first optical fiber and the second optical fiber have different core diameters, thereby improving light intensity receiving efficiency.

[0010] As a feasible implementation, the inner diameter and depth of the polymer tube are related to the area to be detected, thereby meeting the sensor size requirements of different arterial regions.

[0011] As a feasible implementation, the signal processing module comprises: a characteristic parameter extraction unit configured to extract a first characteristic parameter and a second characteristic parameter, the first characteristic parameter being configured to indicate time domain variation information of the arterial pulse signal, and the second characteristic parameter being configured to indicate frequency domain variation information of the arterial pulse signal; and a blood pressure estimation unit configured to estimate a blood pressure value according to the first characteristic parameter and the second characteristic parameter by using a pre-trained algorithm model. The pre-trained algorithm can be a machine learning algorithm, such as a regression tree, a linear regression, a neural network, or any algorithm model that can be used for a regression task. The machine learning algorithm is used to establish an algorithm model of the first characteristic parameter, the second characteristic parameter, systolic pressure, and diastolic pressure. The blood pressure value is calculated by inputting the first and second characteristic parameters into the pre-trained algorithm model. In this way, the cardiovascular characteristic parameters are extracted according to the time and frequency domain variations of the arterial pulse signal, and the blood pressure value is accurately estimated.

[0012] As a feasible implementation, the liquid drop sensitization module comprises at least: a liquid drop unit configured to transmit the arterial pulse signal without attenuation, and a capsule unit configured to encapsulate and store the liquid drop unit, and arranged at a bottom layer of the liquid drop sensitization module to fit the wrist arterial area. In this way, the arterial pulse detected from any point at the bottom of the recessed area of the capsule unit is transmitted to the pressure sensing module without attenuation. Compared with the conventional point detection or line detection of the pulse signal, the sensing area and sensing sensitivity can be greatly improved, and spatial insensitivity can be achieved.

[0013] As a feasible implementation, the capsule unit has a recessed circular arc structure. In this way, the capsule unit can be closely fitted on the human wrist at all times, adapt to various wrist postures, and will not produce relative displacement with the wrist bending within a certain range, so that continuous blood pressure monitoring for various postures can be achieved.

[0014] In a second aspect, the application provides a preparation method of a blood pressure monitoring sensor, which comprises: manufacturing a pressure sensing module, including: manufacturing a polymer optical fiber probe; encapsulating the polymer optical fiber probe in an encapsulation film sheet by using a first mold; and connecting the polymer optical fiber probe with a light transmitting unit and a light receiving unit to obtain the pressure sensing module; manufacturing a liquid drop sensitization module, including: manufacturing a capsule unit by using a second mold; and dropping a liquid medium into the capsule unit to obtain the liquid drop sensitization module; sealing the liquid medium in the liquid drop sensitization module by using the encapsulation film sheet encapsulating the polymer optical fiber probe; and connecting a signal processing module with the pressure sensing module to obtain the blood pressure monitoring sensor. The preparation method of the blood pressure monitoring sensor provided in the application is easy to implement and has a simple preparation process, and batch production can be achieved.

[0015] As a feasible implementation, the polymer optical fiber probe is prepared by the following steps: a polymer tube is prepared, the polymer tube is hollow inside and made of polymer; the same material as the polymer tube is wrapped around one end of a first optical fiber to form an input end, and the same material as the polymer tube is wrapped around one end of a second optical fiber to form an output end; the input end and the output end are respectively sealed and connected with two ends of the polymer tube by a double-layer curing method to form a closed cavity, and a core of the first optical fiber is disconnected from a core of the second optical fiber inside the closed cavity. Thus, the polymer optical fiber probe preparation process is simple and has strong repeatability.

[0016] As a feasible implementation, the second mold comprises a female mold and a male mold; the female mold comprises a concave arc region, a capsule edge region, a female drainage groove and a drainage region; the male mold comprises a convex arc region and a male drainage region; a gap exists between the male mold and the female mold after being connected, and a distance value of the gap is a value of a thickness of the capsule unit.

[0017] In a third aspect, the present application provides a blood pressure monitoring method, which is applied to the blood pressure monitoring sensor in any one of the first aspect, and can be used to monitor blood pressure in daily life without professional operation.

[0018] In a fourth aspect, the present application provides a blood pressure monitoring device, which is used to be worn on the wrist of a user and can be used to detect blood pressure data of the user in real time; the blood pressure monitoring device comprises a body, a first wristband and a second wristband; the body comprises the blood pressure monitoring sensor in any one of the first aspect; one end of the first wristband is connected with the body; the other end of the second wristband is connected with the body. The blood pressure monitoring device provided by the embodiments of the present application can be a smart bracelet or a smart watch, and the whole device can be closely attached to the skin of a human body, and discomfort is not introduced in the measurement stage, so that continuous blood pressure measurement with non-invasion, non-sleeve and high comfort can be realized, and the problems of the traditional sleeve type auscultation measurement device, such as incapability of continuous monitoring of blood pressure value and low comfort, are solved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the multiple embodiments disclosed in the specification, the following will briefly introduce the drawings needed to be used in the embodiments.

[0020] The following will briefly introduce the drawings needed to be used in the embodiments or the prior art description.

[0021] Figure 1A connection diagram of a blood pressure monitoring sensor provided by an embodiment of the present application;

[0022] Figure 2 A polymer optical fiber probe structure diagram provided by an embodiment of the present application;

[0023] Figure 3 A capsule unit female mold structure diagram provided by an embodiment of the present application;

[0024] Figure 4 A capsule unit male mold structure diagram provided by an embodiment of the present application;

[0025] Figure 5A A droplet sensitization module preparation process diagram of a blood pressure monitoring sensor provided by an embodiment of the present application;

[0026] Figure 5B A pressure sensing module 2 preparation process diagram of a blood pressure monitoring sensor provided by an embodiment of the present application;

[0027] Figure 5C A droplet-probe capsule structure process diagram of a blood pressure monitoring sensor provided by an embodiment of the present application;

[0028] Figure 6 A blood pressure monitoring device diagram provided by an embodiment of the present application. DETAILED DESCRIPTION

[0029] In the following description, "some embodiments" are described, which describe a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0030] In the following description, the terms "first\second\third, etc." or module A, module B, module C, etc. are used only to distinguish similar objects, and do not represent a specific order of the objects. It can be understood that the specific order or sequence can be interchanged as allowed, so that the present application described herein can be implemented in an order other than that illustrated or described herein.

[0031] In the following description, the labels indicating steps such as S110, S120, etc. do not necessarily mean that the steps are executed in this order. The order of the steps can be interchanged or executed simultaneously as allowed.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0033] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. The specific embodiments described herein are merely intended to explain the present application and not to limit the present application.

[0034] The first possible blood pressure monitoring method is a pulse transit time (PTT) method. A pulse sensor is used to collect a pulse signal and an electrocardiogram (ECG) signal at a wrist part. The pulse signal and the ECG signal are combined to analyze a time difference between pulse wave and ECG signal peaks. The time difference is defined as a value of the pulse transit time PTT. A blood pressure calculation model based on the pulse transit time is further established.

[0035] The PTT method usually uses a photo plethysmo graphy (PPG) sensor to detect blood volume changes in living tissues by means of photoelectric means. When a light beam of a certain wavelength irradiates the skin surface of the finger, the contraction and expansion of blood vessels will affect the transmission of light at each heartbeat. When the light transmits through the skin tissue and then transmits to the photosensitive sensor, the light will have a certain attenuation. For example, the absorption of light by muscles, bones, veins and other connecting tissues is basically unchanged, provided that the measurement site does not have a large movement. Since there is blood pulsation in the arteries, the absorption of light will naturally change. When the light is converted into an electrical signal, due to the change in the absorption of light by the arteries and the basically unchanged absorption of light by other tissues, the obtained signal can be divided into a direct current (DC) signal and an alternating current (AC) signal. The AC signal can reflect the characteristics of blood flow.

[0036] The independent variable for measuring blood pressure by the PTT method is only the pulse transit time PTT. However, the human body is a complex system, and there are many factors that affect blood pressure. Therefore, the PTT method does not consider enough physiological factors, and the accuracy of blood pressure measurement is not high.

[0037] The premise of measuring blood pressure by the PTT method is to collect a pulse signal by means of a PPG sensor. In the process of collecting the pulse signal, it is easy to be disturbed by skin color and environmental light. The PPG signals collected by people with different skin colors will have a large difference, which further brings errors to blood pressure measurement. The brightness of environmental light will also affect the pulse signal measured by PPG. The PPG sensor cannot continuously obtain a high-fidelity human pulse signal, i.e., the signal-to-noise ratio of the pulse signal is low, so the blood pressure measurement error is large.

[0038] When measuring blood pressure using the PTT method, the PPG sensor must be placed on the wrist, finger, or any other area with noticeable arterial pulsation to capture the pulse waveform. Contact force, mechanical motion artifacts, the subject's posture, and breathing can all distort the pulse signal. This method has strict requirements on the measurement position and is not adaptable to various wrist postures.

[0039] Example 1

[0040] Figure 1 A blood pressure monitoring sensor connection diagram provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the blood pressure monitoring sensor includes a droplet sensitization module 1, a pressure sensing module 2 and a signal processing module 3. Among them, the droplet sensitization module 1 is arranged at the bottom layer of the blood pressure monitoring sensor, and is close to the skin surface of the user's wrist when the user wears the blood pressure monitoring bracelet, and is used to transmit micro-pressure signals carrying cardiovascular physiological rhythm information; the pressure sensing module 2 is located above the droplet sensitization module 1, and is used to sense the arterial pulse signal transmitted by the droplet sensitization module 1. Under the micro-pressure of the arterial pulse signal, the internal polymer optical fiber probe bends and deforms, and modulates the light signal according to the light intensity loss caused by the bending deformation, and converts the modulated light signal into an electrical signal for output. The pressure sensing module 2 transmits the fluctuating electrical signal to the signal processing module 3, and the signal processing module 3 is used to extract cardiovascular characteristic parameters from the electrical signal to calculate the blood pressure value, thereby realizing real-time continuous blood pressure monitoring and measurement.

[0041] In one possible embodiment, the droplet-sensitizing module 1 includes a droplet unit 11 and a capsule unit 12. The capsule unit 12 is disposed at the bottom layer of the droplet-sensitizing module 1 and is used to encapsulate and store the droplet unit 11. The droplet unit 11 is a liquid and is used as a transmission medium for transmitting micro-pressure signals without attenuation.

[0042] In one possible embodiment, the capsule unit 12 may have an arc-shaped concave structure and be made of a polymer material with low Young's modulus, good biocompatibility, strong hydrophobicity, corrosion resistance, and flexibility. For example, the capsule unit 12 may be made of silicone elastomer (Ecoflex) or polydimethylsiloxane (PDMS).

[0043] In one possible embodiment, the droplet unit 11 is a quasi-static, high-boiling-point, non-toxic, low-density liquid substance. For example, the droplet unit 11 may be glycerol, or a liquid substance having the same or similar physical properties as glycerol.

[0044] The flexible structure of the droplet sensitization module 1 can adapt to various wrist postures. When the droplet sensitization module 1 is close to the skin surface of the user's wrist, the pulse signal caused by the arterial pulse can be captured, which carries rich information about the cardiovascular health level and is closely related to the blood pressure level. When the wrist is bent within a certain range, the capsule unit 12 can always effectively adhere to the skin. According to the Pascal principle, the pressure change at any point in a stationary restricted fluid will be transmitted to all points in the fluid without attenuation. The arterial pulse detected at any point in the circular arc-shaped recessed bottom region of the capsule unit 12 will be transmitted to the pressure sensing module 2 without attenuation. Compared with the traditional sensor using point detection or line detection to detect the pulse signal, the flexible structure of the droplet sensitization module 1 greatly increases the sensing area, improves the sensing sensitivity, realizes the spatial insensitivity of the sensor, and makes the alignment requirement of the sensor position and the arterial pulse area less demanding.

[0045] In a possible implementation, the pressure sensing module 2 includes a light sending unit 21, a polymer optical fiber probe 22, a light receiving unit 23, and a flexible packaging unit 24. The polymer optical fiber probe 22 is packaged inside the flexible packaging unit 24. The light sending unit 21 is connected to the input end of the polymer optical fiber probe 22. The output end of the polymer optical fiber probe 22 is connected to the light receiving unit 23. The light receiving unit 23 transmits signals to the signal processing module 3.

[0046] The light sending unit 21 emits continuous probe light signals to the polymer optical fiber probe 22. The probe light signals can be referred to as first light signals.

[0047] The polymer optical fiber probe 22 is used to convert the regular changes of the arterial pulse signal into light intensity signals. The arterial pulse signal is used as a modulation signal to modulate the light signal in the polymer optical fiber probe. The light signal carries cardiovascular physiological rhythm information.

[0048] In a possible implementation, the polymer optical fiber probe 22 senses the arterial pulse signal. Under the micro-pressure action of the arterial pulse signal, the internal polymer tube is bent and deformed, causing the light intensity of the probe light signal to be lost during the transmission between the optical fibers. The arterial pulse signal is used as a modulation signal to modulate the output light intensity loss signal. The modulated output light signal can be referred to as a second light signal. Exemplarily, the polymer optical fiber probe 22 is a transmission structure, and the material can be polyethylene.

[0049] The light receiving unit 23 is used to receive the second light signal output by the polymer optical fiber probe 22 and convert the second light signal into an electrical signal output to the signal processing module 3 for subsequent signal processing. The electrical signal can be an analog signal or a digital signal.

[0050] The flexible packaging unit 24 is two square membranes for packaging the polymer optical fiber probe 22.

[0051] Exemplarily, the material of the flexible packaging unit 24 can be Ecoflex or PDMS. Such material has a low Young's modulus, a weak pressure can cause a significant deformation thereof, a low refractive index, and can form a waveguide structure with the polymer optical fiber probe 22, thereby effectively binding the optical field and reducing the optical loss. Meanwhile, such material has good biocompatibility, strong hydrophobicity, and corrosion resistance.

[0052] The signal processing module 3 is configured to perform initial processing such as filtering and noise elimination on the electrical signal output by the pressure sensing module 2, extract cardiovascular characteristic parameters, establish an algorithm of the cardiovascular characteristic parameters and blood pressure, and then calculate the blood pressure.

[0053] In a possible implementation, the signal processing module 3 includes a characteristic parameter extraction unit 31 and a blood pressure estimation unit 32. The characteristic parameter extraction unit 31 is configured to extract a cardiovascular characteristic parameter corresponding to a time-domain change of the pulse and a cardiovascular characteristic parameter corresponding to a frequency-domain change of the pulse in the electrical signal. The cardiovascular characteristic parameter indicating the time-domain change of the pulse can be referred to as a first characteristic parameter, and the cardiovascular characteristic parameter indicating the frequency-domain change of the pulse can be referred to as a second characteristic parameter. The blood pressure estimation unit 32 is configured to estimate a blood pressure value according to the first characteristic parameter and the second characteristic parameter by using a pre-trained algorithm model. The pre-trained algorithm can be a machine learning algorithm. The machine learning algorithm is configured to establish a training model of the first characteristic parameter, the second characteristic parameter, systolic pressure, and diastolic pressure. The blood pressure value is calculated by inputting the first and second characteristic parameters into the pre-trained algorithm model.

[0054] In a possible implementation, the signal processing module 3 further includes a model training unit 33. The model training unit 33 is configured to train an algorithm model of the first characteristic parameter, the second characteristic parameter, systolic pressure, and diastolic pressure by using a pre-trained algorithm. Exemplarily, the algorithm model of the first characteristic parameter, the second characteristic parameter, systolic pressure, and diastolic pressure is trained by using a machine learning algorithm.

[0055] The liquid drop sensitization module 1 and the pressure sensing module 2 are used to sense the pulse signal carrying the cardiovascular physiological rhythm information. The liquid drop sensitization module 1 is mainly used to sense the micro-pressure change of the pulse signal. Since the pressure change at any point in the static limited fluid is transmitted to all points in the fluid without attenuation, the arterial pulse monitored at any point in the recessed area at the bottom of the capsule unit 12 is transmitted to the pressure sensing module 2 without attenuation, the stringent alignment requirement between the sensor position and the pulse beat area is reduced, the point-type sensing and line-type sensing area in the prior art is converted into a surface-type sensing area, and the sensing area is expanded.

[0056] The blood pressure monitoring sensor proposed in the embodiments of this application is suitable for use in smart wearable devices such as blood pressure monitoring bracelets and watches. It has the advantages of high sensitivity and a large sensing area. Wearable blood pressure monitoring bracelets using this blood pressure monitoring sensor adapt to various wrist postures, provide accurate, stable, and comfortable detection results, and can be used for continuous blood pressure monitoring, accurately acquiring pulse wave information in real time.

[0057] Figure 2 A schematic diagram of the structure of the polymer optical fiber probe provided in the embodiment of the present application is shown in FIG. Figure 2 As shown, the polymer optical fiber probe 22 includes an input end 221, an optical fiber A, a polymer tube 222, an optical fiber B, and an output end 223. The input end 221 is wrapped in the outer layer of one end of the optical fiber A, and the optical fiber at the other end of the optical fiber A is exposed; the output end 223 is wrapped in the outer layer of one end of the optical fiber B, and the optical fiber at the other end of the optical fiber B is exposed. The polymer tube 222 is hollow inside and forms a closed cavity with the input end 221 and the output end 223. The closed cavity is filled with air medium, and the cores of optical fibers A and B are disconnected. Optical fiber A can be recorded as the first optical fiber, and optical fiber B can be recorded as the second optical fiber. The first optical fiber is used to receive a continuous optical signal and transmit it to the second optical fiber; the second optical fiber is used to output a second optical signal.

[0058] In one possible implementation, the core diameters of optical fibers A and B are different. For example, the core diameter of optical fiber A is 62.5 μm, the core diameter of optical fiber B is 100 μm, and the cladding diameters of the input end 221 and the output end 223 are both 125 μm.

[0059] Preferably, the core diameter of the optical fiber A at the light input end is smaller than the core diameter of the optical fiber B at the light output end, so as to obtain a better light receiving effect.

[0060] The blood pressure monitoring sensor proposed in this application uses a polymer optical fiber probe 22 as a sensing transducer device. The diameter of the polymer optical fiber is at the micron level, which is more sensitive to external signals, has a response time of less than 10ms, and has no lag effect, thereby greatly improving the sensing sensitivity.

[0061] The polymer optical fiber probe 22 can sense the arterial pulse signal carrying the cardiovascular physiological pulsation information as a sensing transducer. The size of the sensing area is determined by the length and diameter of the polymer optical fiber probe 22. When the light enters the polymer tube 222 through the optical fiber A of the input end 221 and propagates statically, a part of the reflected and refracted light is radiated from the polymer tube 222 to the environment, and the loss of the part of the light is basically unchanged and can be ignored. When the micro pressure generated by the pulse beat causes the polymer tube 222 to bend and deform, the transmission process of the transmitted light is leaked. The more the elastic polymer tube 222 deforms, the more the light is lost. The size of the transmission loss regularly changes with the micro pressure generated by the pulse beat, and the part of the signal reflects the modulation effect of the pulse micro pressure signal on the transmitted light. Due to the refraction and reflection of the incident light, the bending or extrusion of the soft and elastic polymer tube 222 causes the size of the transmission loss of the light in the structure to regularly change with the micro pressure of the arterial pulse beat. The measurement of the electrical signal changing with the light intensity of the output optical fiber B realizes the measurement of the micro pressure of the pulse signal and obtains the blood pressure value.

[0062] The core of the blood pressure monitoring sensor provided in the embodiment of the application is the polymer optical fiber probe 22. When the micro pressure of the pulse beat acts on the polymer optical fiber probe 22, the polymer tube 222 bends and deforms, the transmission light intensity in the optical fiber changes, and further causes the change of the transmitted light intensity of the polymer optical fiber probe 22, that is, the pulse signal modulates the transmitted light. The monitoring of the change of the transmitted light intensity of the optical fiber B can realize the monitoring of the pulse signal.

[0063] In a possible implementation, the polymer tube 222 with different inner diameters and depths can be arranged to realize the packaging of optical fibers with different diameters to meet the requirements of different arterial regions on the size of the sensor. The inner diameter and depth of the polymer tube 222 determine the length and diameter of the polymer optical fiber probe 22.

[0064] The blood pressure monitoring sensor provided in the embodiment of the application adopts the polymer optical fiber probe 22 as a sensing transducer. When the external micro pressure acts on the optical fiber, the transmission light intensity in the optical fiber changes, and further causes the change of the transmitted light intensity of the polymer optical fiber probe. Compared with the traditional piezoresistive pressure sensor, the response time is fast, the pulse wave with high signal-to-noise ratio is more easily obtained, the cardiovascular characteristic parameters are easily extracted, and the blood pressure is accurately calculated. The monitoring of the transmitted light intensity of the polymer optical fiber probe can realize the monitoring of the pulse signal and meet the real-time blood pressure monitoring requirement.

[0065] Embodiment 2

[0066] An embodiment of the present application provides a method for preparing a blood pressure monitoring sensor, which determines the number and size of the mold body of the capsule unit 12 according to the length of the optical fiber A, polymer tube 222, and optical fiber B of the polymer optical fiber probe 22 and the size of the flexible packaging unit 24; prepares a droplet sensitization module 1; then prepares the polymer optical fiber probe 22 in the pressure sensing module 2; then prepares the flexible packaging unit 24 in the droplet sensitization module 1, and encapsulates and protects the polymer optical fiber probe 22 in the flexible packaging unit 24 to obtain the pressure sensing module 2; bonds the pressure sensing module 2 and the droplet sensitization module 1 together to form the sensing body of the blood pressure monitoring sensor; then connects the output end of the optical sending unit 21 to the input end of the polymer optical fiber probe 22, the output end of the polymer optical fiber probe 22 is connected to the optical receiving unit 23, and the optical receiving unit 23 is connected to the signal processing module 3, so as to obtain a complete blood pressure monitoring sensor.

[0067] It should be understood that the timing relationship of the steps in the various method embodiments described in this application is only for the convenience of expression and is not intended to be limiting. The order of multiple steps can be interchanged based on what is logically achievable.

[0068] In one possible embodiment, the mold body includes a female mold of the capsule unit 12 , a male mold of the capsule unit 12 , and a mold of the flexible packaging unit 24 .

[0069] The mold for the flexible packaging unit 24 is a rectangular concave mold. For example, the rectangular concave region can be 300 μm deep, 25 mm long, and 20 mm wide. The packaging membrane can be made of a polymer material with low Young's modulus, low refractive index, good biocompatibility, strong hydrophobicity, and corrosion resistance, such as PDMS polymer.

[0070] Figure 3 Schematic diagram of the structure of the mother mold of the capsule unit 12 provided in the embodiment of the present application. Figure 3 As shown, the female mold 101 includes an arc-shaped recessed area 41, a capsule edge area 42 outside the arc-shaped recessed area 41, and a drainage groove 43 and a drainage area 44 outside the capsule edge area 42, which can effectively alleviate the flash phenomenon caused by the extrusion of the male and female molds.

[0071] In a possible embodiment, the diameter of the arc-shaped recessed area 41 may be 10 mm, the depth may be 3 mm, and the length may be 15 mm; the length of the capsule edge area 42 may be 25 mm and the width may be 20 mm.

[0072] Figure 4 This is a schematic diagram of the male mold structure of the capsule unit provided in the embodiment of the present application, as shown in FIG. Figure 4 As shown, the male mold 102 includes an arc-shaped raised area 45 and a male drainage area 46 .

[0073] In a possible implementation, the diameter of the circular-arc convex region 45 can be 10 mm.

[0074] Figures 5A-5C A schematic diagram of a preparation process of a sensing body of a blood pressure monitoring sensor is provided in the embodiments of the present application. In the embodiments, the material of the polymer optical fiber probe 22 is polyethylene, the flexible packaging unit 24 is a square film, a PDMS film is used, the capsule unit 12 is made of Ecoflex material, the droplet unit 11 is made of glycerol, and the preparation process of the sensing body of the blood pressure monitoring sensor includes the following steps: S1, preparing a droplet sensitization module; S2, preparing a probe packaging structure in a pressure sensing module; S3, preparing a droplet-probe capsule structure; and S4, preparing a blood pressure monitoring sensor. The following will be specifically introduced in combination with the drawings:

[0075] S1, preparing a droplet sensitization module 1, as shown in FIG. 1, including steps S11-S13. Figure 5A

[0076] S11, determining the number and size of a mold for preparing the capsule unit 12, and the mold body includes a female mold 101 and a male mold 102.

[0077] In a possible implementation, the number and size of the mold body are determined according to the length of the polymer optical fiber probe 22 and the size of the flexible packaging unit 24. The size of the female mold 101 including the concave circular-arc region, the capsule edge region, the female drainage groove and the drainage region is determined, and the size of the male mold 102 including the convex circular-arc region and the male drainage region is determined.

[0078] S12, preparing the capsule unit 12 by using the female mold 101 and the male mold 102.

[0079] In a possible implementation, a prepolymer is prepared according to a proper mixing ratio, and the prepolymer solution is filled into the concave circular-arc region 41 of the female mold 101; when the flowability of the prepolymer solution is reduced, the male mold is covered on the female mold and aligned; after the prepolymer is solidified, the male mold 102 is removed, and the solidified capsule unit 12 is taken out from the female mold 101.

[0080] For example, the Ecoflex prepolymer can be prepared according to the corresponding ratio of monomers and curing agents, and the prepolymer is poured into the concave circular-arc region 41 of the female mold 101. Due to the volume expansion effect in the curing process, the prepolymer overflowed from the recessed region of the capsule edge region can be observed when the flowability of the prepolymer is reduced.

[0081] In a possible implementation, the ratio of the monomers and the curing agents of the prepolymer can be adjusted, and different ratios of mixing can result in different refractive indexes and Young's moduli after solidification.

[0082] ​In one possible embodiment, if the edge area of ​​the female mold 101 is filled with prepolymer, the male mold 102 is covered; if the edge area of ​​the female mold 101 is free of prepolymer, Ecoflex prepolymer is added to the edge area and then the male mold 102 is covered.

[0083] In one possible embodiment, the female mold 101 is designed with a female drainage groove, a male drainage area, and a female drainage area. When making a high-precision mold, flash will appear because the male mold 102 is extruded outside the target molding area. The drainage groove and the drainage area are used to purposefully drain the extruded prepolymer to ensure the structural integrity of the target molding area, thereby alleviating the flash phenomenon caused by the extrusion of the male and female molds.

[0084] In a possible embodiment, a gap of several hundred microns is reserved between the male and female membranes after they are connected, and the gap distance is the thickness of the capsule unit 12 .

[0085] In one possible embodiment, the female mold 101 and the male mold 102 are made of acrylic material. Acrylic material has high hardness, stable structure, strong hydrophobicity, and low viscosity to polymers, which facilitates the release of the capsule unit 12 from the mold.

[0086] S13, preparing a droplet sensitization module 1.

[0087] In a possible embodiment, glycerol is dripped into the prepared capsule unit 12 to ensure that the glycerol does not overflow from the recessed area of ​​the capsule unit 12 to obtain the droplet sensitization module 1.

[0088] S2, making the probe packaging structure in the pressure sensing module, such as Figure 5B As shown, steps S21-S23 are included.

[0089] S21, preparing a polymer optical fiber probe 22, including steps S211-S213:

[0090] S211, preparing an elastic hollow polymer tube 222.

[0091] In one possible embodiment, the elastic hollow polymer tube 222 may be prepared using polyethylene material by 3D printing.

[0092] In one possible embodiment, 3D printing can be used to prepare polymer tubes 222 with different inner diameters and depths to achieve optical fiber packaging with different diameters and sizes, thereby meeting the sensor size requirements of different arterial regions.

[0093] For example, a polymer tube 222 having an outer diameter of 200-300 μm, an inner diameter of 130-150 μm, and a length of about 6-10 mm can be prepared by 3D printing.

[0094] In one possible embodiment, a polymer material with good chemical resistance, a smooth inner wall, and excellent crack resistance and aging resistance can be selected to prepare the polymer tube 222 using a 3D printing method.

[0095] In a possible embodiment, other molding processes may also be used to manufacture the elastic hollow polymer tube 222 .

[0096] S212, using the same material as the polymer tube 222, the polymer material is wrapped around one end of the optical fiber A by 3D printing to form the input end 221, and the polymer material is wrapped around one end of the optical fiber B by 3D printing to form the output end 223.

[0097] S213 , using a double-layer curing method, the input end 221 of the optical fiber A and the output end 223 of the optical fiber B are sealed and connected to the two ends of the polymer tube 222 respectively, to form a polymer optical fiber probe 22 .

[0098] In one possible embodiment, an elastic hollow polymer tube 222 can be sealed and connected between the input end 221 including optical fiber A and the output end 223 including optical fiber B, and the closed cavity of the polymer tube 222 is filled with air medium, and the cores of optical fibers A and B are exposed and disconnected.

[0099] For example, a first layer of curing is performed using a UV-curing adhesive with high viscosity and low refractive index to connect the input end 221 and the output end 223 to the two ends of the elastic hollow polymer tube 222 and seal them. After the first layer of UV-curing adhesive is cured, a UV-curing adhesive with low viscosity and high tensile strength is applied to the connection between the input end 221 and the output end 223 and the two ends of the polymer tube 222 to strengthen the connection, and then a second layer of curing is performed. After curing, the polymer optical fiber probe 22 is formed. The UV-curing adhesive with high viscosity and low refractive index can be denoted as the first UV-curing adhesive, and the UV-curing adhesive with low viscosity and high tensile strength can be denoted as the second UV-curing adhesive.

[0100] S22, preparing a flexible packaging unit 24, including two packaging films.

[0101] In one possible embodiment, a PDMS polymer can be prepared with a monomer:curing agent ratio of 10:1. The PDMS polymer is poured into the mold of the flexible packaging unit 24. After standing for 24 hours, the polymer solidifies, and the packaging film is removed. There are two packaging films. The mold of the flexible packaging unit 24 can be referred to as the first mold.

[0102] In a possible embodiment, the ratio of the monomer to the curing agent in the prepolymer can be adjusted, and mixing in different ratios can result in different refractive indices and Young's moduli after curing.

[0103] Exemplarily, the thickness of the encapsulation film can be about 300 um, the length 25 mm, and the width 20 mm.

[0104] S23, a droplet-probe capsule structure is made. The polymer optical fiber probe 22 is encapsulated between the two encapsulation films of the flexible encapsulation unit 24 to obtain a probe encapsulation structure 51.

[0105] In a possible implementation, the polymer optical fiber probe 22 is encapsulated along the central axis of the encapsulation film to form a probe encapsulation structure 51 of encapsulation film-polymer probe-encapsulation film, and the polymer optical fiber probe 22 is sealed in the flexible encapsulation unit 24.

[0106] S3, the glycerol in the droplet sensitization module 1 is sealed using the probe encapsulation structure 51, as shown in Figure 5C to obtain a droplet-probe capsule structure 52 of the blood pressure monitoring sensor.

[0107] In a possible implementation, the probe encapsulation structure 51 is bonded to the droplet sensitization module 1 using the silicone adhesive to bond the edge area of the capsule unit 12 and the flexible encapsulation unit 24 encapsulating the polymer optical fiber probe 22, to obtain the droplet-probe capsule structure 52.

[0108] In a possible implementation, the PDMS prepolymer can be applied to the edge area of the capsule unit 12, and the flexible encapsulation unit 24 encapsulating the polymer optical fiber probe 22 is vertically placed on the upper part of the capsule unit 12; after the PDMS prepolymer in the edge area of the capsule unit 12 is cured, the droplet unit 11 (glycerol) is encapsulated between the recessed area of the capsule unit 12 and the film of the flexible encapsulation unit 24. According to the capsule unit 12, the droplet unit 11, the flexible encapsulation unit 24, and the polymer optical fiber probe 22, the droplet-probe capsule structure 52 is obtained. At this point, the sensing main part of the blood pressure monitoring sensor has been obtained.

[0109] S4, a blood pressure monitoring sensor is made. After the droplet-probe capsule structure 52 is made, the light sending unit 21 is connected to the input end of the polymer optical fiber probe 22, the output end of the polymer optical fiber probe 22 is connected to the light receiving unit 23, and the light receiving unit 23 is connected to the signal processing module 3, so that a complete blood pressure monitoring sensor can be obtained.

[0110] The preparation method of the blood pressure monitoring sensor provided in the embodiments of the present application has a simple preparation process and can realize batch production. The materials used in the preparation method provided in the embodiments of the present application are easy to obtain, the whole method process is easy to implement, the cost is low, the operation is reliable, the preparation method has strong repeatability, and batch production can be realized.

[0111] Further, the blood pressure monitoring sensor obtained by the manufacturing method provided in the embodiments of the present application can realize continuous blood pressure monitoring in a large sensing area with high sensitivity, and can adapt to high-precision blood pressure monitoring of various wrist postures.

[0112] Embodiment 3

[0113] The embodiments of the present application also provide a blood pressure monitoring method. The blood pressure monitoring sensor provided in the embodiments 1 or 2 of the present application is used to collect a pulse signal carrying cardiovascular physiological rhythm information, and the pulse signal is converted into a fluctuant light intensity signal. The fluctuant light intensity signal is converted into an electric signal output. After initial processing such as filtering and denoising on the electric signal, cardiovascular characteristic parameters are extracted, an algorithm model of the cardiovascular characteristic parameters and blood pressure is established, and then the blood pressure is calculated.

[0114] In a possible implementation, a first characteristic parameter reflecting time domain changes of the pulse in the electric signal and a second characteristic parameter reflecting frequency domain changes of the pulse can be extracted respectively. The blood pressure value is estimated by using a pre-trained algorithm model according to the first characteristic parameter and the second characteristic parameter. The pre-trained algorithm can be a machine learning algorithm, which is used to establish an algorithm model of the first characteristic parameter, the second characteristic parameter, systolic pressure and diastolic pressure, and the blood pressure value is calculated by inputting the first and second characteristic parameters into the pre-trained algorithm model.

[0115] In a possible implementation, a machine learning algorithm can be used to train an algorithm model of the first characteristic parameter, the second characteristic parameter, systolic pressure and diastolic pressure. The algorithm model includes a systolic pressure algorithm model and a diastolic pressure algorithm model.

[0116] The blood pressure monitoring sensor in the embodiments of the present application can restore high-fidelity pulse waveforms, so that cardiovascular characteristic parameters including amplitude, time, area and the like which can reflect the degree of cardiovascular health are extracted in the pulse wave, and a blood pressure calculation model based on comprehensive cardiovascular characteristic parameters is established. In the construction of the blood pressure calculation model, various physiological characteristic parameters related to blood pressure are considered, the independent variable factors are more comprehensive compared with the PTT method, the blood pressure measurement accuracy is higher, and the accuracy of blood pressure measurement is greatly improved.

[0117] Embodiment 4

[0118] Figure 6 A blood pressure monitoring device is provided in the embodiments of the present application. The device is worn on the wrist of a user and can detect blood pressure data of the user in real time. As shown in FIG. 1, the blood pressure monitoring device includes a body 61, a blood pressure monitoring sensor 62 included in the body 61, a first wristband 63 connected to one end of the body 61, and a second wristband 64 connected to the other end of the body 61. Figure 6 As shown in FIG. 1, the blood pressure monitoring device includes a body 61, a blood pressure monitoring sensor 62 included in the body 61, a first wristband 63 connected to one end of the body 61, and a second wristband 64 connected to the other end of the body 61.

[0119] The blood pressure monitoring device provided by the embodiments of the present application can be a smart bracelet or a smart watch, can be closely attached to the human skin, and can not introduce discomfort in the measurement stage, so that continuous blood pressure measurement with non-invasiveness, non-sleeve and high comfort can be achieved, and problems such as the inability of the traditional cuff type auscultation measurement device to continuously monitor blood pressure values and low comfort are solved.

[0120] The blood pressure monitoring device provided by the present application can adapt to various wrist postures, the convex liquid drop sensitization module can be closely attached to the human wrist at all times, and relative displacement will not be generated with the bending of the wrist within a certain range, so that blood pressure can be monitored in daily life, and the blood pressure monitoring device is not limited to a static state or a specific posture, and can be used for continuous blood pressure monitoring in various postures.

[0121] The blood pressure monitoring device provided by the embodiments of the present application is based on the ultra-high sensitivity micro-scale optical fiber sensing technology, can realize real-time and accurate monitoring of blood pressure, and provide related health management suggestions.

[0122] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software mode depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present application.

[0123] In addition, various aspects or features of the embodiments of the present application can be implemented as methods, apparatuses or articles of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" used in the present application encompasses computer programs accessible from any computer-readable device, carrier or medium. For example, the computer-readable medium can include, but is not limited to: magnetic storage devices (for example, hard disk, floppy disk or magnetic tape, etc.), optical discs (for example, compact disc (CD), digital versatile disc (DVD), etc.), smart cards and flash memory devices (for example, erasable programmable read-only memory (EPROM), card, stick or key drive, etc.). In addition, the various storage media described herein can represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" can include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0124] It should be understood that the magnitude of the sequence number of each process described above does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0125] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0126] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0127] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0128] If the function is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application essentially or the parts that make contributions to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or an access network device, etc.) to execute all or part of the steps of the various embodiments of the method of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0129] The above merely illustrates the specific implementation of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the embodiments of the present application, which should be covered in the protection scope of the embodiments of the present application.

Claims

1. A blood pressure monitoring sensor, characterized by, At least comprising: a droplet sensitization module for transmitting an arterial pulse signal; a pressure sensing module for generating an electrical signal according to the arterial pulse signal; the pressure sensing module comprises a light transmitting unit, a polymer optical fiber probe and a light receiving unit; the light transmitting unit is connected with a first optical fiber for transmitting a first light signal; the first optical fiber is used for receiving the continuous first light signal and transmitting to a second optical fiber; the second optical fiber is used for outputting a second light signal; the polymer optical fiber probe is used for deforming according to the arterial pulse signal; the second light signal is obtained according to the first light signal and the arterial pulse signal; wherein the arterial pulse signal is used as a modulation signal of the first light signal, and the second light signal is a modulated output light signal; the light receiving unit is connected with the second optical fiber for generating the electrical signal according to the second light signal; a signal processing module is used for extracting cardiovascular characteristic parameters according to the electrical signal to obtain a blood pressure value; the polymer optical fiber probe comprises: an input end comprising a first optical fiber; an output end comprising a second optical fiber; a polymer tube for forming a closed cavity with the input end and the output end, and the fiber core of the first optical fiber is disconnected from the fiber core of the second optical fiber in the closed cavity.

2. The blood pressure monitoring sensor of claim 1, wherein, The diameters of the fiber core of the first optical fiber and the fiber core of the second optical fiber are different.

3. The blood pressure monitoring sensor of claim 1 or 2, wherein, The inner diameter and depth of the polymer tube are related to the to-be-detected region.

4. The blood pressure monitoring sensor of claim 1 or 2, wherein, The signal processing module comprises: a characteristic parameter extraction unit for extracting a first characteristic parameter and a second characteristic parameter, the first characteristic parameter being used for indicating time domain variation information of the arterial pulse signal, and the second characteristic parameter being used for indicating frequency domain variation information of the arterial pulse signal; a blood pressure estimation unit for estimating a blood pressure value according to the first characteristic parameter and the second characteristic parameter by using a pre-trained algorithm model.

5. The blood pressure monitoring sensor of claim 1 or 2, wherein, The droplet sensitization module comprises: a droplet unit for transmitting the arterial pulse signal without attenuation, the droplet unit being a liquid medium; and a capsule unit for encapsulating and storing the droplet unit, the capsule unit being arranged at the bottom layer of the droplet sensitization module to adhere to the arterial region of a user.

6. The blood pressure monitoring sensor of claim 5, wherein, The capsule unit has a concave circular arc structure.

7. A method of manufacturing a blood pressure monitoring sensor, characterized by, The method comprises: manufacturing a pressure sensing module, including: manufacturing a polymer optical fiber probe; using a first mold to manufacture an encapsulation diaphragm, and encapsulating the polymer optical fiber probe in the encapsulation diaphragm; connecting the polymer optical fiber probe with a light transmitting unit and a light receiving unit to obtain the pressure sensing module; the polymer optical fiber probe comprises: an input end comprising a first optical fiber; an output end comprising a second optical fiber; and a polymer tube for forming a closed cavity with the input end and the output end, and the fiber core of the first optical fiber is disconnected from the fiber core of the second optical fiber in the closed cavity. A pressure sensing module for generating an electrical signal according to an arterial pulse signal; the pressure sensing module comprises a light transmitting unit, a polymer optical fiber probe and a light receiving unit; the light transmitting unit is connected with a first optical fiber for transmitting a first light signal; the first optical fiber is used for receiving the continuous first light signal and transmitting to a second optical fiber; the second optical fiber is used for outputting a second light signal; the polymer optical fiber probe is used for deforming according to the arterial pulse signal; the second light signal is obtained according to the first light signal and the arterial pulse signal; wherein the arterial pulse signal is used as a modulation signal of the first light signal, and the second light signal is a modulated output light signal; the light receiving unit is connected with the second optical fiber for generating the electrical signal according to the second light signal; A liquid droplet sensing module is prepared by: using a second mold to prepare a capsule unit; dropping a liquid medium into the capsule unit to obtain the liquid droplet sensing module; and sealing the liquid medium in the liquid droplet sensing module using the encapsulation film piece encapsulating the polymer optical fiber probe; The liquid droplet sensing module is used for transmitting an arterial pulse signal. A signal processing module is connected with the pressure sensing module to obtain the blood pressure monitoring sensor; the signal processing module is used for extracting a cardiovascular characteristic parameter according to the electrical signal to obtain a blood pressure value.

8. The method of claim 7, wherein, The preparation of the polymer optical fiber probe comprises: A signal processing module is connected with the pressure sensing module to obtain the blood pressure monitoring sensor; A polymer tube is prepared, which is hollow inside and made of polymer; The same material as the polymer tube is wrapped on one end of the first optical fiber to form an input end, and the same material as the polymer tube is wrapped on one end of the second optical fiber to form an output end; A double-layer curing method is used to seal and connect the input end and the output end with both ends of the polymer tube respectively to form a closed cavity, and the core of the first optical fiber and the core of the second optical fiber are disconnected inside the closed cavity.

9. The method according to claim 7 or 8, characterized in that, The second mold comprises a female mold and a male mold; the female mold comprises a concave arc region, a capsule edge region, a female drainage groove and a drainage region; The male mold comprises a convex arc region and a male drainage region; There is a gap between the male and female molds after connection, and the distance value of the gap is the thickness value of the capsule unit.

10. A blood pressure monitoring device, characterized by The blood pressure monitoring device is used for wearing on the wrist of a user and can detect blood pressure data of the user in real time; the blood pressure monitoring device comprises: A machine body comprising the blood pressure monitoring sensor according to any one of claims 1 to 6; A first wristband connected with one end of the machine body; A second wristband connected with the other end of the machine body.

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