A flexible micro-wave gas sensor for non-invasive blood glucose monitoring

Abstract

The application discloses a flexible microwave gas sensor for noninvasive blood glucose monitoring and relates to the technical field of noninvasive blood glucose monitoring.The application comprises a body surface detection unit, a processing unit, a gas flow module and an environmental temperature and humidity module, wherein the body surface detection unit comprises a blood oxygen module, a microwave module, a near-infrared module, a blood flow rate module and a body surface temperature and humidity module, the output ends of the blood oxygen module, the microwave module, the near-infrared module, the blood flow rate module and the body surface temperature and humidity module are connected with the input end of the processing unit, and the output end of the environmental temperature and humidity module is connected with the input end of the processing unit.The application combines multiple noninvasive blood glucose detection technologies to improve the blood glucose detection accuracy of a wearer, avoids interference caused by body differences among the wearers, sets the gas flow module to realize different air flow rates on the body surface of the wearer, avoids interference caused by environmental differences and indirectly improves the accuracy of blood glucose detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-invasive blood glucose monitoring, in particular to a flexible microwave gas sensor for non-invasive blood glucose monitoring. BACKGROUND

[0002] Non-invasive blood glucose monitoring is divided into near-infrared spectroscopy technology, microwave spectrum analysis technology and metabolic heat integration method. Near-infrared has a relatively ideal detection spectrum. In the near-infrared NIR spectrum range, light has a relatively strong ability to penetrate biological liquids and soft tissues, and the penetration ability is greater than 0.5mm. Compared with ultraviolet or visible light, it has less scattering, and blood glucose measurement can be achieved through the absorption spectrum of reflected and transmitted light. The detection method based on mid-infrared spectrum can only use the absorption spectrum of reflected light, and the approximate glucose concentration value can be inferred through the absorption peaks of glucose in the absorption spectrum of transmitted light and reflected light. Microwave spectrum analysis technology is that when the microwave injected into the human body encounters glucose molecules in the human blood, the phase, amplitude, etc. of the microwave will change. Different concentrations of glucose solution have different effects on microwaves. By analyzing the changes in the phase and amplitude of the microwaves, the purpose of calculating the blood glucose concentration can be achieved. The principle of metabolic heat integration method is to calculate blood glucose by testing physiological parameters related to human metabolism and basic physiological information of the human body. The testable parameters include environmental temperature, environmental humidity, human body surface temperature, human body surface humidity, blood flow rate, and blood oxygen saturation. Based on the metabolic heat integration method, combined with the near-infrared spectroscopy technology, non-invasive and rapid measurement of blood glucose is realized.

[0003] The near-infrared spectroscopy technology has the following disadvantages: 1. The intensity of the spectrum signal related to blood glucose received by the sensor is weak; 2. There are many other interference factors in the tissue, which can produce similar near-infrared spectrum as glucose, and many variable parameters need to be added for calibration; 3. The glucose concentration in the capillary blood vessels, tissue gaps and veins in the human body is unevenly distributed; The microwave spectrum analysis technology has the following disadvantages: the phase difference caused by the difference in wearing position will indirectly affect the accuracy of blood glucose calculation; The metabolic heat integration method has the following disadvantages: metabolic calculation will cause errors due to differences in the physical conditions of the measured person and the environment; Therefore, how to combine the above technologies to improve the accuracy of blood glucose calculation is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a flexible microwave gas sensor for non-invasive blood glucose monitoring, which solves the problems raised in the background art.

[0005] To achieve the above object, the present application is implemented by the following technical solutions: A flexible microwave gas sensor for non-invasive blood glucose monitoring, comprising a body surface detection unit, a processing unit, a gas flow module and an environmental temperature and humidity module, the body surface detection unit comprises an oxygen module, a microwave module, a near-infrared module, a blood flow rate module and a body surface temperature and humidity module, the output ends of the oxygen module, the microwave module, the near-infrared module, the blood flow rate module and the body surface temperature and humidity module are connected with the input end of the processing unit, the output end of the environmental temperature and humidity module is connected with the input end of the processing unit, and the output end of the processing unit is connected with the input end of the gas flow module;

[0006] The gas sensor further comprises a flexible circuit board, the body surface detection unit, the processing unit, the gas flow module and the environmental temperature and humidity module are integrated on the flexible circuit board, the outside of the flexible circuit board is a ring-shaped protective shell, the ring-shaped protective shell is worn on the arm of a user to realize non-invasive blood glucose detection, and the gas sensor comprises the following steps when working:

[0007] Step 1: near-infrared spectrum analysis, the processing unit executes a near-infrared spectrum analysis program to obtain a first blood glucose index c1;

[0008] Step 2: microwave analysis, the processing unit executes a microwave analysis program to obtain a second blood glucose index c2;

[0009] Step 3: metabolic heat integration analysis, the processing unit executes a blood flow rate analysis program to obtain a first metabolic index dx1, the processing unit executes an oxygen saturation analysis program to obtain a second metabolic index dx2, and the processing unit executes a temperature and humidity difference analysis program to obtain a third metabolic index dx3;

[0010] Step 4: comprehensive weight analysis, the processing unit presets weight coefficients w1, w2 and w3, the weight coefficients w1, w2 and w3 satisfy the condition w1+w2+w3=1, and the weight coefficients w1, w2 and w3 determine specific values according to the body fat rate of the wearer, and the processing unit calculates the blood glucose value XT of the wearer according to the formula

[0011] Further, the near-infrared spectrum analysis program specifically comprises the following steps:

[0012] Step 101: the near-infrared module sends near-infrared light to the body surface of the wearer, the incident light intensity is I1, and the near-infrared module obtains the near-infrared light reflected by the body surface of the wearer, and the reflected light intensity is I2;

[0013] Step 102: the near-infrared module transmits the incident light intensity I1 and the reflected light intensity I2 to the processing unit;

[0014] Step 103: the processing unit calculates the absorbance IA of the body surface of the wearer according to the formula and then calculates the absorbance IA of the body surface of the wearer according to the formula​ The first blood glucose index c1,e of the wearer is calculated, c1,e is the molar concentration of blood glucose, which is a constant value, and L is the optical path length, which is determined by the specific parameters of the near-infrared module.

[0015] Further, the microwave analysis procedure specifically includes the following steps:

[0016] Step 201: The microwave module sends a microwave signal of a specific frequency f1 to the wearer's body surface, the microwave module acquires the microwave signal returned from the wearer's body surface, the microwave module records the time t1 of the transmission and return, and the microwave module transmits the time t1, the initial phase, the initial signal intensity E and the specific frequency f to the processing unit;

[0017] Step 202: The processing unit calculates the phase of the returned microwave signal according to the formula Further, the microwave analysis procedure specifically includes the following steps:

[0018] Step 203: The body surface temperature and humidity module acquires the temperature information T1 of the wearer's body surface and transmits it to the processing unit;

[0019] Step 204: The processing unit calculates the second blood glucose index c2,f1 according to the formula

[0020] Further, the blood flow rate analysis is based on the principle of ultrasonic Doppler, the blood flow rate module is a micro ultrasonic transceiver, and the blood flow rate analysis procedure specifically includes the following steps:

[0021] Step 301: The blood flow rate module sends a transmission wave to the wearer's body, the transmission wave frequency is f2, the transmission wave and the blood flow rate angle is θ, the transmission wave becomes a reflected wave after entering the wearer's body, the blood flow rate module acquires the returned reflected wave, and the blood flow rate module subtracts the transmission wave from the reflected wave to obtain the Doppler frequency shift f3;

[0022] Step 302: The blood flow rate module transmits the transmission wave frequency f2, the angle θ and the Doppler frequency shift f3 to the processing unit;

[0023] Step 303: The processing unit calculates the blood flow rate v in the wearer's body according to the formula

[0024] Step 304: The processing unit calculates the blood flow rate v in the wearer's body according to the formula ​​​​The first metabolic index dx1,m of the wearer is calculated, and the weight information of the wearer is manually inputted into the processing unit by the medical staff in advance.

[0025] Further, the blood oxygen module is composed of an infrared emitter and a photodetector, and the blood oxygen saturation analysis program specifically includes the following steps:

[0026] Step 305: The infrared emitter sends infrared light into the body of the wearer, and the infrared light becomes reflected infrared light after being emitted in the body of the wearer, which is acquired by the photodetector. The blood oxygen module obtains the blood oxygen saturation xy according to the intensity ratio of the transmitted infrared light and the received reflected infrared light, and the formula is

[0027] Step 306: The processing unit calculates the second metabolic index dx2,age of the wearer according to the formula The second metabolic index dx2,age of the wearer is calculated, and the age information of the wearer is manually inputted into the processing unit by the medical staff in advance. The Δdx is the metabolic compensation value, and the specific value is determined according to the gender of the wearer. The male is 0.25, and the female is 0.18. The gender of the wearer is also manually inputted into the processing unit by the medical staff in advance.

[0028] Further, the working frequency f4 of the gas flow module is divided into a first level of 23 Hz / s, a second level of 60 Hz / s, and a third level of 120 Hz / s. The working frequency f4 is the frequency of the gas flow module being applied with alternating voltage and pulse voltage. The greater the working frequency f4, the faster the speed of the gas flow module to transport air. The temperature and humidity difference analysis program specifically includes the following steps:

[0029] Step 307: The processing unit controls the working frequency f4 of the gas flow module to be the first level, the body surface temperature and humidity module acquires the temperature tw1 and humidity ts1 of the body surface of the wearer and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw1 and humidity hs1 of the environment and transmits them to the processing unit;

[0030] Step 308: The processing unit controls the working frequency f4 of the gas flow module to be the second level, the body surface temperature and humidity module acquires the temperature tw2 and humidity ts2 of the body surface of the wearer and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw2 and humidity hs2 of the environment and transmits them to the processing unit;

[0031] Step 309: The processing unit controls the working frequency f4 of the gas flow module to be the third level, the body surface temperature and humidity module acquires the temperature tw3 and humidity ts3 of the body surface of the wearer and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw3 and humidity hs3 of the environment and transmits them to the processing unit;

[0032] Step 310: The processing unit calculates the temperature and humidity difference according to the formula The third metabolic index dx3 of the wearer is calculated, the air flow module is arranged to achieve different air flow rates on the surface of the wearer, and the temperature and humidity differences under different air flow rates are referred to, so that the metabolic index of the wearer is better calculated, the accuracy of blood glucose detection is indirectly improved, and interference caused by environmental differences is avoided.

[0033] Further, the surface temperature and humidity module and the environmental temperature and humidity module are both tubular structures, the outer layer of the tubular structure is a packaging tube shell, and the inner layer of the tubular structure is a silicon-based electrode.

[0034] Further, the gas flow module comprises a device shell, an air inlet is formed in the top of the device shell, a partition plate is fixedly connected between the inner walls of the gas flow module, a one-way hole is formed in the center of the partition plate, the bottom of the device shell is divided into a cavity by the partition plate, an air outlet pipe penetrates through one side of the device shell, one end of the air outlet pipe towards the inside of the device shell is in communication with the cavity, and the other end of the air outlet pipe away from the cavity is in communication with the surface temperature and humidity module and the environmental temperature and humidity module.

[0035] The top of the partition plate is fixedly connected with two bases on both sides, the opposite sides of the two bases are fixedly connected with the inner walls of the device shell on both sides, the top of each base is fixedly connected with the inner top surface of the device shell, and the opposite sides of the two bases are fixedly connected with a first thin film metal and a second thin film metal respectively.

[0036] Further, the gas flow module is divided into a first stage and a second stage when it is running, and air flow is realized through continuous repetition of the first stage and the second stage.

[0037] In the first stage, the processing unit applies alternating voltage to the first piezoelectric ceramic through the two bases, the top of the first piezoelectric ceramic is the positive electrode, the bottom of the first piezoelectric ceramic is the negative electrode, the surface of the first piezoelectric ceramic shrinks and thickens, driving the first thin film metal to bend downward, the processing unit applies pulse unidirectional voltage to the second piezoelectric ceramic through the two bases, the top of the second piezoelectric ceramic is the negative electrode, the bottom of the second piezoelectric ceramic is the positive electrode, the surface of the second piezoelectric ceramic relaxes and thins, driving the second thin film metal to bend upward.

[0038] When the first thin film metal bends downward, the pressure in the area above the first thin film metal decreases, the air outside the device shell is sucked into the inside of the device shell through the air inlet, at this time, the air gap is located in the area above the first thin film metal, at the same time, the second thin film metal bends upward, the air between the second thin film metal and the first thin film metal is squeezed, the squeezed air enters the area at the bottom of the second thin film metal through the gap between the second thin film metal and the inner wall of the device shell, and the first stage ends.

[0039] Further, in the second stage, the processing unit disconnects the second piezoelectric ceramic circuit through the two bases, the second piezoelectric ceramic deformation recovers to drive the second thin film metal to be in a horizontal state, the processing unit applies an alternating voltage to the first piezoelectric ceramic through the two bases, the top of the first piezoelectric ceramic is negative, and the bottom of the first piezoelectric ceramic is positive, the surface of the first piezoelectric ceramic shrinks and thickens to drive the first thin film metal to bend upward;

[0040] When the second thin film metal gradually recovers to the horizontal state, the air at the bottom of the second thin film metal is continuously pressed, the air at the bottom of the second thin film metal passes through the one-way hole into the cavity, the pressure inside the cavity increases, the air originally inside the cavity flows to the outside of the device shell through the air outlet pipe, and when the second thin film metal is completely in the horizontal state, the second thin film metal bottom contacts the top surface of the baffle to cover the one-way hole, at this time, the air entering the cavity cannot flow back into the area between the second thin film metal and the baffle through the one-way hole, and the first thin film metal bends upward, and under the premise that the one-way hole is covered by the second thin film metal, the air at the top of the first thin film metal flows into the area between the first thin film metal and the second thin film metal from the gap between the first thin film metal and the inner wall of the device shell, the second stage ends, and the first stage is continuously started to execute, and the air outside the device shell enters the area above the first thin film metal through the air inlet again.

[0041] Through continuous circulation of the first stage and the second stage, air is sequentially from the air inlet, the top area of the first thin film metal, the area between the first thin film metal and the second thin film metal, the area at the bottom of the second thin film metal, the one-way hole and the cavity, and finally air flows out from the air outlet pipe.

[0042] The present application has the following beneficial effects:

[0043] 1. By combining various non-invasive blood glucose detection technologies, the blood glucose detection accuracy of the wearer is improved, and interference caused by body differences between wearers is avoided.

[0044] 2. By setting the gas flow module, different air flow rates on the body surface of the wearer can be achieved, and the differences in temperature and humidity under different air flow rates are referred to, so that the metabolic index of the wearer is better calculated, the accuracy of blood glucose detection is indirectly improved, and interference caused by environmental differences is avoided.

[0045] Of course, any product implementing the present application does not necessarily need to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0047] Figure 1 System block diagram of a flexible microwave gas sensor for non-invasive blood glucose monitoring according to the present application;

[0048] Figure 2 Structure diagram of a body surface temperature and humidity module and an environmental temperature and humidity module according to the present application;

[0049] Figure 3 Internal structure diagram of a gas flow module according to the present application;

[0050] Figure 4 Structure diagram of a first stage of a gas flow module according to the present application;

[0051] Figure 5 Structure diagram of a second stage of a gas flow module according to the present application;

[0052] Figure 6 Voltage application diagram of a first piezoelectric ceramic and a second piezoelectric ceramic according to the present application.

[0053] In the drawings, the components represented by the respective reference numerals are listed as follows:

[0054] In the drawings, 1 is a package tube, 2 is a silicon-based electrode, 3 is a gas flow module, 301 is a device housing, 302 is an air inlet, 303 is a partition, 304 is a one-way hole, 305 is a cavity, 306 is an air outlet tube, 307 is a base, 308 is a first thin film metal, 309 is a first piezoelectric ceramic, 310 is a second thin film metal, and 311 is a second piezoelectric ceramic. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0056] Please refer to Figure 1The application provides a technical scheme: a flexible microwave gas sensor for non-invasive blood glucose monitoring, which comprises a body surface detection unit, a processing unit, a gas flow module 3 and an environmental temperature and humidity module, the body surface detection unit comprises a blood oxygen module, a microwave module, a near-infrared module, a blood flow rate module and a body surface temperature and humidity module, the output ends of the blood oxygen module, the microwave module, the near-infrared module, the blood flow rate module and the body surface temperature and humidity module are connected with the input end of the processing unit, the output end of the environmental temperature and humidity module is connected with the input end of the processing unit, and the output end of the processing unit is connected with the input end of the gas flow module 3.

[0057] The gas sensor further comprises a flexible circuit board, the body surface detection unit, the processing unit, the gas flow module 3 and the environmental temperature and humidity module are integrated on the flexible circuit board, the outside of the flexible circuit board is a ring-shaped protective shell, the ring-shaped protective shell is worn on the arm of a user to realize non-invasive blood glucose detection, and the gas sensor comprises the following steps when working:

[0058] Step 1: near-infrared spectrum analysis, the processing unit executes a near-infrared spectrum analysis program to obtain a first blood glucose index c1;

[0059] Step 2: microwave analysis, the processing unit executes a microwave analysis program to obtain a second blood glucose index c2;

[0060] Step 3: metabolic heat integrated analysis, the processing unit executes a blood flow rate analysis program to obtain a first metabolic index dx1, the processing unit executes a blood oxygen saturation analysis program to obtain a second metabolic index dx2, and the processing unit executes a temperature and humidity difference analysis program to obtain a third metabolic index dx3;

[0061] Step 4: comprehensive weight analysis, the processing unit predefines weight coefficients w1, w2 and w3, the weight coefficients w1, w2 and w3 satisfy the condition w1+w2+w3=1, the weight coefficients w1, w2 and w3 determine specific values according to the body fat rate of the wearer, and the processing unit calculates the blood glucose value XT of the wearer according to the formula

[0062] The near-infrared spectrum analysis program specifically comprises the following steps:

[0063] Step 101: the near-infrared module sends near-infrared light to the body surface of the wearer, the incident light intensity is I1, the near-infrared module acquires the near-infrared light reflected by the body surface of the wearer, and the reflected light intensity is I2;

[0064] Step 102: the near-infrared module transmits the incident light intensity I1 and the reflected light intensity I2 to the processing unit;

[0065] Step 103: the processing unit calculates the absorbance IA of the body surface of the wearer according to the formula and then calculates the absorbance IA of the body surface of the wearer according to the formula ​The first blood glucose index c1,e of the wearer is calculated, c1,e is the molar concentration of blood glucose, which is a constant value, and L is the optical path length, which is determined by the specific parameters of the near-infrared module.

[0066] The microwave analysis program specifically includes the following steps:

[0067] Step 201: The microwave module sends a microwave signal of a specific frequency f1 to the wearer's body surface, the microwave module acquires the returned microwave signal from the wearer's body surface, the microwave module records the time t1 of the transmission and return, and the microwave module transmits the time t1, the initial phase, the initial signal intensity E and the specific frequency f to the processing unit;

[0068] Step 202: The processing unit calculates the phase of the returned microwave signal according to the formula And calculates the phase difference of the microwave signal according to the formula

[0069] Step 203: The body surface temperature and humidity module acquires the temperature information T1 of the wearer's body surface and transmits it to the processing unit;

[0070] Step 204: The processing unit calculates the second blood glucose index c2,f1 according to the formula , where c2,f1 is the second blood glucose index, f1 is the specific frequency of the microwave signal, and μ is the vacuum permeability. The magnetic permeability in the human body is approximately equal to the vacuum magnetic permeability μ, so the vacuum magnetic permeability is used instead of the human magnetic permeability for calculation.

[0071] The blood flow rate analysis is based on the ultrasonic Doppler principle, and the blood flow rate module is a micro ultrasonic transceiver. The blood flow rate analysis program specifically includes the following steps:

[0072] Step 301: The blood flow rate module sends a transmission wave to the wearer's body, the transmission wave frequency is f2, the transmission wave and the blood flow rate angle is θ, the transmission wave becomes a reflected wave after entering the wearer's body, the blood flow rate module acquires the returned reflected wave, and the blood flow rate module subtracts the transmission wave from the reflected wave to obtain the Doppler shift f3;

[0073] Step 302: The blood flow rate module transmits the transmission wave frequency f2, the angle θ and the Doppler shift f3 to the processing unit;

[0074] Step 303: The processing unit calculates the blood flow rate v in the wearer's body according to the formula , where δ is the propagation speed of the transmission wave and the reflected wave in the wearer's body, which is generally 1540 meters / second;

[0075] Step 304: The processing unit calculates the blood flow rate v in the wearer's body according to the formula ​​The first metabolic index dx1,m of the wearer is calculated, and the weight information of the wearer is manually inputted into the processing unit by the medical staff in advance.

[0076] The blood oxygen module is composed of an infrared emitter and a photoelectric detector, and the blood oxygen saturation analysis program specifically includes the following steps:

[0077] Step 305: The infrared emitter sends infrared light into the wearer's body, and the infrared light becomes reflected infrared light after being emitted in the wearer's body and is acquired by the photoelectric detector. The blood oxygen module obtains the blood oxygen saturation xy according to the intensity ratio of the transmitted infrared light and the received reflected infrared light, and the formula is

[0078] Step 306: The processing unit calculates the second metabolic index dx2,age of the wearer according to the formula The second metabolic index dx2,age of the wearer is calculated, and the age information of the wearer is manually inputted into the processing unit by the medical staff in advance. The Δdx is the metabolic compensation value, and the specific value is determined according to the gender of the wearer. The male is 0.25, and the female is 0.18. The gender of the wearer is also manually inputted into the processing unit by the medical staff in advance.

[0079] The working frequency f4 of the gas flow module 3 is divided into a first level 23Hz / s, a second level 60Hz / s and a third level 120Hz / s. The working frequency f4 is the frequency at which the gas flow module 3 is applied with alternating voltage and pulse voltage. The greater the working frequency f4, the faster the speed of the gas flow module 3 to transport air. The temperature and humidity difference analysis program specifically includes the following steps:

[0080] Step 307: The processing unit controls the working frequency f4 of the gas flow module 3 to be the first level, the body surface temperature and humidity module acquires the temperature tw1 and humidity ts1 of the wearer's body surface and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw1 and humidity hs1 of the environment and transmits them to the processing unit;

[0081] Step 308: The processing unit controls the working frequency f4 of the gas flow module 3 to be the second level, the body surface temperature and humidity module acquires the temperature tw2 and humidity ts2 of the wearer's body surface and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw2 and humidity hs2 of the environment and transmits them to the processing unit;

[0082] Step 309: The processing unit controls the working frequency f4 of the gas flow module 3 to be the third level, the body surface temperature and humidity module acquires the temperature tw3 and humidity ts3 of the wearer's body surface and transmits them to the processing unit, and the environmental temperature and humidity module acquires the temperature hw3 and humidity hs3 of the environment and transmits them to the processing unit;

[0083] Step 310: The processing unit calculates the temperature difference Δtw and the humidity difference Δts according to the formula A third metabolic index dx3 of the wearer is calculated.

[0084] As shown in Figure 2 , the body surface temperature and humidity module and the environment temperature and humidity module are both tubular structures, the outer layer of the tubular structure is an encapsulation tube shell 1, the inner layer of the tubular structure is a silicon-based electrode 2, air enters the inside of the tubular structure along the A direction, the silicon-based electrode 2 contacts the air to obtain temperature and humidity information, and the air is discharged along the B direction. The air enters one end of the tubular structure and communicates with the gas flow module 3, the encapsulation tube shell 1 can improve the structural strength of the body surface temperature and humidity module and the environment temperature and humidity module, increase the durability, and on the other hand, it can improve the efficiency of the silicon-based electrode 2 contacting the air, and improve the detection accuracy of the body surface temperature and humidity module and the environment temperature and humidity module.

[0085] As shown in Figures 3-5 , the gas flow module 3 includes a device shell 301, the device shell 301 is provided with an air inlet 302 at the top, the gas flow module 3 is fixedly connected between the inner walls of the two sides of the device shell 301, a one-way hole 304 is formed in the center of the baffle 303, the baffle 303 divides the bottom of the device shell 301 into a cavity 305, an air outlet pipe 306 penetrates one side of the device shell 301, one end of the air outlet pipe 306 facing the inside of the device shell 301 communicates with the cavity 305, and the other end of the air outlet pipe 306 away from the cavity 305 communicates with the body surface temperature and humidity module and the environment temperature and humidity module respectively;

[0086] The top of the baffle 303 is fixedly connected with two bases 307 respectively, the two bases 307 are fixedly connected with the inner walls of the two sides of the device shell 301 respectively, the top of the two bases 307 is fixedly connected with the inner top surface of the device shell 301, and the opposite side of the two bases 307 is fixedly connected with a first thin film metal 308 and a second thin film metal 310 respectively, the top of the first thin film metal 308 is fixedly connected with a first piezoelectric ceramic 309, and the top of the second thin film metal 310 is fixedly connected with a second piezoelectric ceramic 311.

[0087] The gas flow module 3 is divided into a first stage and a second stage during operation, and the air flow is realized by continuous repetition of the first stage and the second stage;

[0088] As shown in Figure 6As shown, the vertical axis is voltage V and the horizontal axis is time t. In the first stage, the processing unit applies an alternating voltage to the first piezoelectric ceramic 309 through the two bases 307. The top of the first piezoelectric ceramic 309 is the positive electrode, and the bottom of the first piezoelectric ceramic 309 is the negative electrode. The surface of the first piezoelectric ceramic 309 shrinks and becomes thicker, driving the first thin film metal 308 to bend downward. The processing unit applies a pulsed unidirectional voltage to the second piezoelectric ceramic 311 through the two bases 307. The top of the second piezoelectric ceramic 311 is the negative electrode, and the bottom of the second piezoelectric ceramic 311 is the positive electrode. The surface of the second piezoelectric ceramic 311 relaxes and becomes thinner, driving the second thin film metal 310 to bend upward. In the first stage, the voltage between the first piezoelectric ceramic 309 and the second piezoelectric ceramic 311 is Figure 6 middle ab segment;

[0089] like Figure 4 As shown, when the first thin film metal 308 bends downward, the pressure in the area above the first thin film metal 308 decreases, and the air outside the device housing 301 is sucked into the device housing 301 through the air inlet 302. At this time, the vacancy is located in the area above the first thin film metal 308. At the same time, the second thin film metal 310 bends upward, and the air between the second thin film metal 310 and the first thin film metal 308 is squeezed. The squeezed air passes through the gap between the second thin film metal 310 and the inner wall of the device housing 301 and enters the area at the bottom of the second thin film metal 310, and the first stage ends.

[0090] Among them, such as Figure 6 As shown, in the second stage, the processing unit disconnects the circuit of the second piezoelectric ceramic 311 through the two bases 307. The second piezoelectric ceramic 311 recovers its deformation and drives the second thin film metal 310 to a horizontal state. The processing unit applies an alternating voltage to the first piezoelectric ceramic 309 through the two bases 307. The top of the first piezoelectric ceramic 309 is the negative electrode, and the bottom of the first piezoelectric ceramic 309 is the positive electrode. The surface of the first piezoelectric ceramic 309 shrinks and becomes thicker, driving the first thin film metal 308 to bend upward. In the second stage, the voltage between the first piezoelectric ceramic 309 and the second piezoelectric ceramic 311 is Figure 6 middle bc segment;

[0091] like Figure 5As shown, the second thin film metal 310 gradually restores the horizontal state, constantly extruding the air at the bottom of the second thin film metal 310, the air at the bottom of the second thin film metal 310 enters the cavity 305 through the one-way hole 304, the pressure inside the cavity 305 increases, the air originally inside the cavity 305 flows to the outside of the device shell 301 through the air outlet pipe 306, because the top center of the partition plate 303 is slightly convex, when the second thin film metal 310 is completely in the horizontal state, the second thin film metal 310 at the bottom contacts the top surface of the partition plate 303 to cover the one-way hole 304, at this time the air entering the cavity 305 cannot flow back into the area between the second thin film metal 310 and the partition plate 303 through the one-way hole 304, the first thin film metal 308 bends upward, under the premise that the one-way hole 304 is covered by the second thin film metal 310, the air at the top of the first thin film metal 308 will flow into the area between the first thin film metal 308 and the second thin film metal 310 from the gap between the first thin film metal 308 and the inner wall of the device shell 301, the second stage ends, and the first stage continues to be executed, the air outside the device shell 301 enters the area above the first thin film metal 308 through the air inlet 302 again.

[0092] Through the continuous circulation of the first stage and the second stage, the air realizes the sequence from the air inlet 302, the top area of the first thin film metal 308, the area between the first thin film metal 308 and the second thin film metal 310, the area at the bottom of the second thin film metal 310, the one-way hole 304 and the cavity 305, and finally the air flows out from the air outlet pipe 306.

[0093] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A flexible microwave gas sensor for non-invasive blood glucose monitoring, characterized by: The device comprises a body surface detection unit, a processing unit, a gas flow module (3) and an environmental temperature and humidity module, wherein the body surface detection unit comprises a blood oxygen module, a microwave module, a near infrared module, a blood flow rate module and a body surface temperature and humidity module, wherein the output ends of the blood oxygen module, the microwave module, the near infrared module, the blood flow rate module and the body surface temperature and humidity module are all connected to the input end of the processing unit, the output end of the environmental temperature and humidity module is connected to the input end of the processing unit, and the output end of the processing unit is connected to the input end of the gas flow module (3); The gas sensor also includes a flexible circuit board. The body surface detection unit, the processing unit, the gas flow module (3) and the ambient temperature and humidity module are all integrated on the flexible circuit board. The flexible circuit board is provided with an annular protective shell on the outside. The user wears the annular protective shell on the arm to realize non-invasive blood glucose detection. When the gas sensor is working, the following steps are included: Step 1: The processing unit executes a near infrared spectroscopy analysis program to obtain a first blood glucose index c1; Step 2: The processing unit executes a microwave analysis program to obtain a second blood glucose index c2; Step 3: The processing unit executes a blood flow velocity analysis program to obtain a first metabolic index dx1, executes a blood oxygen saturation analysis program to obtain a second metabolic index dx2, and executes a temperature and humidity difference analysis program to obtain a third metabolic index dx3; Step 4: The processing unit presets weight coefficients w1, w2 and w3. The weight coefficients w1, w2 and w3 satisfy the condition w1+w2+w3=1. According to the formula Calculate the wearer's blood sugar value XT; The operating frequency f4 of the gas flow module (3) is divided into the first level, the second level and the third level. The operating frequency f4 is the frequency at which the alternating voltage and the pulse voltage are applied to the gas flow module (3). The temperature and humidity difference analysis program specifically includes the following steps: Step 307: The processing unit controls the operating frequency f4 of the gas flow module (3) to the first level, the body surface temperature and humidity module obtains the wearer's body surface temperature tw1 and humidity ts1 and transmits them to the processing unit, and the environment temperature and humidity module obtains the environment temperature hw1 and humidity hs1 and transmits them to the processing unit; Step 308: Control the operating frequency f4 of the gas flow module (3) to the second level, the body surface temperature and humidity module obtains the wearer's body surface temperature tw2 and humidity ts2 and transmits them to the processing unit, and the environment temperature and humidity module obtains the environment temperature hw2 and humidity hs2 and transmits them to the processing unit; Step 309: Control the operating frequency f4 of the gas flow module (3) to the third level, the body surface temperature and humidity module obtains the wearer's body surface temperature tw3 and humidity ts3 and transmits them to the processing unit, and the environment temperature and humidity module obtains the environment temperature hw3 and humidity hs3 and transmits them to the processing unit; Step 310: According to the formula The wearer's third metabolic index dx3 is calculated.

2. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The near infrared spectroscopy analysis procedure specifically includes the following steps: Step 101: The near-infrared module sends near-infrared light to the wearer's body surface, and the incident light intensity is I1. The near-infrared module obtains the near-infrared light reflected by the wearer's body surface, and the reflected light intensity is I2. Step 102: The near-infrared module transmits the incident light intensity I1 and the reflected light intensity I2 to the processing unit; Step 103: According to the formula Calculate the absorbance IA of the wearer's body surface, and then use the formula Calculate the wearer's first blood sugar index c1, where e is the molar concentration of blood sugar, which is a fixed value, and L is the optical path length, the value of which is determined by the specific parameters of the near-infrared module.

3. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The microwave analysis procedure specifically includes the following steps: Step 201: The microwave module transmits a microwave signal of a specific frequency f1 to the wearer's body surface. The microwave module obtains the microwave signal returned from the wearer's body surface, records the time t1 from the transmission to the return, and transmits the time t1, initial phase, initial signal strength E, and specific frequency f1 to the processing unit. Step 202: The processing unit calculates the Calculate the phase of the returned microwave signal , and then according to the formula Calculate the phase difference of microwave signals ; Step 203: The body surface temperature and humidity module obtains the wearer's body surface temperature information T1 and transmits it to the processing unit; Step 204: According to the formula Calculate the second blood sugar index c2, f1 is the specific frequency of the microwave signal, is the vacuum permeability, and the magnetic permeability in the human body is approximately the vacuum permeability , so the vacuum magnetic permeability is used instead of the human body magnetic permeability for calculation.

4. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: Blood flow velocity analysis is based on the ultrasonic Doppler principle. The blood flow velocity module is a miniature ultrasonic transceiver. The blood flow velocity analysis procedure specifically includes the following steps: Step 301: The blood flow velocity module sends a transmission wave into the wearer's body. The transmission wave frequency is f2, and the angle between the transmission wave and the blood flow velocity is , the transmitted wave enters the wearer's body and becomes a reflected wave. The blood flow velocity module obtains the returned reflected wave. The blood flow velocity module subtracts the transmitted wave from the reflected wave to obtain the Doppler shift frequency f3; Step 302: The blood flow velocity module transmits the wave frequency f2, the angle and Doppler shift frequency f3 are transmitted to the processing unit; Step 303: According to the formula Calculate the blood flow velocity v in the wearer's body, is the propagation speed of the transmitted and reflected waves in the wearer's body; Step 304: According to the formula Calculate the wearer's first metabolic index dx1, where m is the wearer's weight information.

5. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The blood oxygen module consists of an infrared emitter and a photoelectric detector. The blood oxygen saturation analysis process includes the following steps: Step 305: The infrared transmitter sends infrared light into the wearer's body. After passing through the wearer's body, the infrared light is reflected and captured by the photoelectric detector. The blood oxygen module obtains the blood oxygen saturation xy based on the light intensity ratio of the transmitted infrared light and the received reflected infrared light. The formula is ; Step 306: According to the formula Calculate the wearer's second metabolic index dx2, where age is the wearer's age information. It is the metabolic compensation value, and the specific value is determined by the wearer's gender.

6. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The body surface temperature and humidity module and the ambient temperature and humidity module are both tubular structures. The outer layer of the tubular structure is a packaging tube shell (1), the inner layer of the tubular structure is a silicon-based electrode (2), and one end of the tubular structure is connected to the gas flow module (3).

7. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The gas flow module (3) includes a device housing (301), an air inlet (302) is provided at the top of the device housing (301), a partition (303) is fixedly connected between the two sides of the inner wall of the gas flow module (3), a one-way hole (304) is provided at the center of the partition (303), the partition (303) separates the bottom of the device housing (301) into a cavity (305), an air outlet pipe (306) passes through one side of the device housing (301), the air outlet pipe (306) is connected to the cavity (305) at one end facing the inside of the device housing (301), and the air outlet pipe (306) is connected to the cavity (305) at one end away from the cavity (305), respectively. Two bases (307) are fixedly connected to both sides of the top of the partition (303), and the opposite sides of the two bases (307) are fixedly connected to the inner walls of the device housing (301) on both sides. The tops of the two bases (307) are fixedly connected to the top surface of the device housing (301). The opposite sides of the two bases (307) are fixedly connected to a first thin film metal (308) and a second thin film metal (310), respectively. The top of the first thin film metal (308) is fixedly connected to a first piezoelectric ceramic (309), and the top of the second thin film metal (310) is fixedly connected to a second piezoelectric ceramic (311).

8. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The gas flow module (3) is divided into a first stage and a second stage during operation, and air flow is achieved through continuous repetition of the first stage and the second stage; In the first stage, the processing unit applies an alternating voltage to the first piezoelectric ceramic (309), the top of the first piezoelectric ceramic (309) is a positive electrode, the bottom of the first piezoelectric ceramic (309) is a negative electrode, the surface of the first piezoelectric ceramic (309) contracts and becomes thicker, driving the first thin film metal (308) to bend downward, and the processing unit applies a pulsed unidirectional voltage to the second piezoelectric ceramic (311), the top of the second piezoelectric ceramic (311) is a negative electrode, the bottom of the second piezoelectric ceramic (311) is a positive electrode, the surface of the second piezoelectric ceramic (311) relaxes and becomes thinner, driving the second thin film metal (310) to bend upward; When the first thin film metal (308) bends downward, the pressure in the area above the first thin film metal (308) decreases, and the air outside the device housing (301) is sucked into the inside of the device housing (301) through the air inlet (302). At this time, the vacancy is located in the area above the first thin film metal (308). At the same time, the second thin film metal (310) bends upward, and the air between the second thin film metal (310) and the first thin film metal (308) is squeezed. The squeezed air passes through the gap between the second thin film metal (310) and the inner wall of the device housing (301) and enters the area at the bottom of the second thin film metal (310), and the first stage ends.

9. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 8, characterized in that: In the second stage, the processing unit disconnects the circuit of the second piezoelectric ceramic (311), the second piezoelectric ceramic (311) recovers its deformation and drives the second thin film metal (310) to be in a horizontal state, and the processing unit applies an alternating voltage to the first piezoelectric ceramic (309), the top of the first piezoelectric ceramic (309) is the negative electrode, and the bottom of the first piezoelectric ceramic (309) is the positive electrode, and the surface of the first piezoelectric ceramic (309) shrinks and becomes thicker, driving the first thin film metal (308) to bend upward; As the second thin film metal (310) gradually returns to a horizontal state, it continuously squeezes the air at the bottom of the second thin film metal (310). The air at the bottom of the second thin film metal (310) passes through the one-way hole (304) and enters the cavity (305). The internal pressure of the cavity (305) increases, and the air originally inside the cavity (305) passes through the air outlet pipe (306) and flows to the outside of the device housing (301). Because the center of the top of the partition (303) is slightly raised, when the second thin film metal (310) is completely in a horizontal state, the bottom of the second thin film metal (310) contacts the top surface of the partition (303) to cover the one-way hole (304). At this time, the air entering the cavity (305) cannot Then, the air flows back through the one-way hole (304) into the area between the second thin film metal (310) and the partition (303). The first thin film metal (308) bends upward. Under the premise that the one-way hole (304) is covered by the second thin film metal (310), the air on the top of the first thin film metal (308) flows from the gap between the first thin film metal (308) and the inner wall of the device housing (301) into the area between the first thin film metal (308) and the second thin film metal (310). The second stage ends and the first stage is continued. The air outside the device housing (301) passes through the air inlet (302) again and enters the area above the first thin film metal (308). By continuously circulating the first and second stages, the air is sequentially discharged from the air inlet (302), the top area of ​​the first thin film metal (308), the area between the first thin film metal (308) and the second thin film metal (310), the bottom area of ​​the second thin film metal (310), the one-way hole (304) and the cavity (305), and finally the air flows out from the air outlet pipe (306).

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