Flexible microwave gas sensor for noninvasive blood glucose monitoring

Abstract

The invention discloses a flexible microwave gas sensor for noninvasive blood glucose monitoring, and relates to the technical field of noninvasive blood glucose monitoring. The system comprises a body surface detection unit, a processing unit, a gas flow module and an environment temperature and humidity module, and 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 end of the blood oxygen module, the output end of the microwave module, the output end of the near-infrared module, the output end of the blood flow rate module and the output end of the body surface temperature and humidity module are all connected with the input end of the processing unit, and the output end of the environment temperature and humidity module is connected with the input end of the processing unit. The interference caused by body differences among wearers is avoided, different air flow speeds of the body surfaces of the wearers can be realized by arranging the air flow module, the interference caused by environmental differences is avoided, and the accuracy of blood glucose detection is indirectly improved.

Description

Technical Field

[0001] The invention relates to the technical field of non-invasive blood sugar monitoring, and in particular to a flexible microwave gas sensor for non-invasive blood sugar monitoring. Background Art

[0002] Non-invasive blood glucose monitoring is divided into near-infrared spectroscopy technology, microwave spectroscopy 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 fluids and soft tissues, with a penetration capacity greater than 0.5mm. It has less scattering than ultraviolet or visible light, and can measure blood glucose through the absorption spectrum of reflected and transmitted light. The detection method based on mid-infrared spectroscopy can only use the absorption spectrum of its reflected light, and the approximate glucose concentration value can be inferred through the glucose absorption peak on the absorption spectrum of transmitted and reflected light. Microwave spectroscopy analysis technology is that the phase and amplitude of microwaves injected into the human body will change when encountering glucose molecules in human blood. Glucose solutions of different concentrations have different effects on microwaves. By analyzing the changes in the phase and amplitude of the microwaves, the purpose of calculating 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 ambient temperature, ambient humidity, human body surface temperature, human body surface humidity, blood flow rate, and blood oxygen saturation. Based on metabolic heat integration method, combined with near-infrared spectroscopy technology, non-invasive and rapid measurement of blood glucose can be achieved.

[0003] Near-infrared spectroscopy technology has the following disadvantages: 1. The intensity of the spectral signal related to blood sugar received by the sensor is weak; 2. There are many other interfering factors in the tissue, which will produce a near-infrared spectrum similar to glucose, and many variable parameters need to be added for calibration; 3. The concentration of glucose in the capillaries, tissue gaps, and veins of the human body is unevenly distributed; Microwave spectroscopy analysis technology has the following disadvantages: Microwaves will cause phase differences due to different wearing locations, indirectly affecting the accuracy of blood sugar measurement; The metabolic heat integration method has the following disadvantages: Metabolic measurement will cause errors due to differences in the physical condition of the subject and environmental differences; Therefore, how to combine the above technologies to improve the accuracy of blood sugar measurement is a technical problem that technicians in this field need to solve. Summary of the invention

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

[0005] To achieve the above objectives, the present invention is implemented through 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 comprising 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 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;

[0006] The gas sensor also includes a flexible circuit board. The body surface detection unit, the processing unit, the gas flow module and the ambient temperature and humidity module are all integrated on the flexible circuit board. The flexible circuit board is externally provided with an annular protective shell. The user wears the annular protective shell on the arm to realize non-invasive blood glucose detection. The gas sensor includes the following steps when working:

[0007] Step 1: Near infrared spectroscopy analysis: the processing unit executes a near infrared spectroscopy analysis program to obtain a first blood sugar index c1;

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

[0009] Step 3: Metabolic heat integration analysis, the processing unit executes a blood flow velocity 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;

[0010] Step 4: Comprehensive weight analysis, the processing unit presets weight coefficients w1, w2 and w3, the weight coefficients w1, w2 and w3 meet the condition w1+w2+w3=1, w1, w2 and w3 are determined according to the wearer's body fat percentage, and the processing unit determines the specific values ​​according to the formula Calculate the wearer's blood sugar value XT.

[0011] Furthermore, the near infrared spectroscopy analysis procedure specifically includes the following steps:

[0012] Step 101: the near infrared module sends near infrared light to the wearer's body surface, the incident light intensity is I1, and the near infrared module obtains the near infrared light reflected by the wearer's body surface, 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: Processing unit according to 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.

[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 obtains the microwave signal returned from the wearer's body surface, the microwave module records the time t1 from sending to returning, and the microwave module transmits the time t1, the initial phase, the initial signal strength E and the specific frequency f to the processing unit;

[0017] Step 202: The processing unit calculates the Calculate the phase of the returned microwave signal According to the formula Calculate the phase difference of microwave signals

[0018] 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;

[0019] Step 204: The processing unit calculates the The second blood sugar index c2 is calculated, where f1 is the specific frequency of the microwave signal, μ is the vacuum magnetic permeability, and the magnetic permeability in the human body is approximately the vacuum magnetic permeability μ, so the vacuum magnetic permeability is used instead of the human body magnetic permeability for calculation.

[0020] Furthermore, the blood flow velocity analysis is based on the ultrasonic Doppler principle, the blood flow velocity module is a miniature ultrasonic transceiver, and the blood flow velocity analysis procedure specifically includes the following steps:

[0021] 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 θ. After the transmission wave enters the wearer's body, it becomes a reflected wave. The blood flow velocity module obtains the returned reflected wave. The blood flow velocity module subtracts the transmission wave from the reflected wave to obtain the Doppler shift frequency f3.

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

[0023] Step 303: The processing unit calculates the Calculate the blood flow velocity v in the wearer's body, δ is the propagation speed of the transmitted wave and the reflected wave in the wearer's body, generally 1540 m / s;

[0024] Step 304: The processing unit calculates the The first metabolic index dx1 of the wearer is calculated, where m is the weight information of the wearer, and the weight information is manually input into the processing unit in advance by the medical staff and saved.

[0025] Furthermore, the blood oxygen module is composed of an infrared emitter and a photoelectric detector, and the blood oxygen saturation analysis procedure specifically includes the following steps:

[0026] Step 305: The infrared transmitter sends infrared light into the wearer's body. After passing through the wearer's body, the infrared light is transformed into reflected infrared light and captured by the photoelectric detector. The blood oxygen module obtains the blood oxygen saturation xy according to the light intensity ratio of the transmitted infrared light and the received reflected infrared light. The formula is:

[0027] Step 306: The processing unit calculates the The wearer's second metabolic index dx2 is calculated, where age is the wearer's age information, which is manually input into the processing unit by medical staff in advance and saved. Δdx is the metabolic compensation value, and the specific value is determined according to the wearer's gender, which is 0.25 for males and 0.18 for females. The wearer's gender is also manually input into the processing unit by medical staff in advance.

[0028] Furthermore, the working frequency f4 of the gas flow module is divided into the first level 23 Hz / s, the second level 60 Hz / s and the third level 120 Hz / s. The working frequency f4 is the frequency at which the alternating voltage and the pulse voltage are applied to the gas flow module. The greater the working frequency f4, the faster the gas flow module transports 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 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;

[0030] Step 308: the processing unit controls the working frequency f4 of the gas flow module 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;

[0031] Step 309: the processing unit controls the working frequency f4 of the gas flow module 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;

[0032] Step 310: The processing unit calculates the Calculate the wearer's third metabolic index dx3. By setting the gas flow module, different air flow rates on the wearer's body surface can be achieved. Referring to the temperature and humidity differences under different air flow rates, the wearer's metabolic index can be better calculated, which indirectly improves the accuracy of blood sugar detection and avoids interference caused by environmental differences.

[0033] Furthermore, 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 a packaging tube shell, the inner layer of the tubular structure is a silicon-based electrode, and one end of the tubular structure is connected to the gas flow module.

[0034] Furthermore, the gas flow module comprises a device shell, an air inlet is provided at the top of the device shell, a partition is fixedly connected between the two sides of the inner wall of the gas flow module, a one-way hole is provided at the center of the partition, the partition separates a cavity from the bottom of the device shell, an air outlet pipe is passed through one side of the device shell, one end of the air outlet pipe facing the inside of the device shell is connected to the cavity, and one end of the air outlet pipe away from the cavity is respectively connected to the body surface temperature and humidity module and the ambient temperature and humidity module;

[0035] Two bases are fixedly connected to both sides of the top of the partition, and the opposite sides of the two bases are fixedly connected to the inner walls of the device shell on both sides, and the tops of the two bases are fixedly connected to the top surface of the device shell. The opposite sides of the two bases are fixedly connected to the first thin film metal and the second thin film metal, respectively, the top of the first thin film metal is fixedly connected to the first piezoelectric ceramic, and the top of the second thin film metal is fixedly connected to the second piezoelectric ceramic.

[0036] Furthermore, the gas flow module 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;

[0037] In the first stage, the processing unit applies an alternating voltage to the first piezoelectric ceramic through 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 becomes thicker, driving the first thin film metal to bend downward, and the processing unit applies a pulsed unidirectional voltage to the second piezoelectric ceramic through 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 becomes thinner, 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, and the air outside the device casing is sucked into the device casing through the air inlet. At this time, the vacancy is located in the area above the first thin film metal. At the same time, the second thin film metal bends upward, and the air between the second thin film metal and the first thin film metal is squeezed. The squeezed air passes through the gap between the second thin film metal and the inner wall of the device casing and enters the area at the bottom of the second thin film metal, and the first stage ends.

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

[0040] When the second thin film metal gradually recovers its horizontal state, it continuously squeezes the air at the bottom of the second thin film metal. 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 passes through the air outlet pipe and flows to the outside of the device shell. Because the center of the top of the partition is slightly raised, when the second thin film metal is completely in a horizontal state, the bottom of the second thin film metal contacts the top surface of the partition to cover the one-way hole. At this time, the air entering the cavity can no longer pass through the one-way hole and flow back into the area between the second thin film metal and the partition. The first thin film metal bends upward. 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 will flow from the gap between the first thin film metal and the inner wall of the device shell into the area between the first thin film metal and the second thin film metal. The second stage ends and the first stage continues to be executed. The air outside the device shell passes through the air inlet again and enters the area above the first thin film metal.

[0041] Through continuous circulation of the first stage and the second stage, the air flows out 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 bottom area of ​​the second thin film metal, the one-way hole and the cavity in sequence, and finally the air flows out from the air outlet pipe.

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

[0043] 1. By combining a variety of non-invasive blood glucose detection technologies, the wearer's blood glucose detection accuracy is improved, avoiding interference caused by physical differences between wearers.

[0044] 2. By setting up the gas flow module, different air flow rates can be achieved on the wearer's body surface. By referring to the temperature and humidity differences under different air flow rates, the wearer's metabolic index can be better calculated, which indirectly improves the accuracy of blood sugar testing and avoids interference caused by environmental differences.

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

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

[0048] Figure 2 It is a schematic diagram of the structure of the body surface temperature and humidity module and the environment temperature and humidity module of the present invention;

[0049] Figure 3 It is a schematic diagram of the internal structure of the gas flow module of the present invention;

[0050] Figure 4 It is a schematic diagram of the structure of the first stage of the gas flow module of the present invention;

[0051] Figure 5 It is a schematic diagram of the structure of the second stage of the gas flow module of the present invention;

[0052] Figure 6 It is a schematic diagram of applied voltage to the first piezoelectric ceramic and the second piezoelectric ceramic of the present invention.

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

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

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] See also Figure 1The present invention provides a technical solution: a flexible microwave gas sensor for non-invasive blood glucose monitoring, comprising 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 velocity 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 velocity 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;

[0057] The gas sensor also includes a flexible circuit board, on which the body surface detection unit, the processing unit, the gas flow module 3 and the ambient temperature and humidity module are all integrated. 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:

[0058] Step 1: Near infrared spectroscopy analysis: the processing unit executes a near infrared spectroscopy analysis program to obtain a first blood sugar index c1;

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

[0060] Step 3: Metabolic heat integration analysis, the processing unit executes a blood flow velocity 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 presets weight coefficients w1, w2 and w3, the weight coefficients w1, w2 and w3 meet the condition w1+w2+w3=1, w1, w2 and w3 are determined according to the wearer's body fat percentage, and the processing unit determines the specific values ​​according to the formula Calculate the wearer's blood sugar value XT.

[0062] Among them, the near infrared spectroscopy analysis procedure specifically includes the following steps:

[0063] Step 101: the near infrared module sends near infrared light to the wearer's body surface, the incident light intensity is I1, and the near infrared module obtains the near infrared light reflected by the wearer's body surface, 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: Processing unit according to 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.

[0066] The microwave analysis procedure 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 obtains the microwave signal returned from the wearer's body surface, the microwave module records the time t1 from sending to returning, and the microwave module transmits the time t1, the initial phase, the initial signal strength E and the specific frequency f to the processing unit;

[0068] Step 202: The processing unit calculates the Calculate the phase of the returned microwave signal According to the formula Calculate the phase difference of microwave signals

[0069] 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;

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

[0071] Among them, the blood flow velocity analysis is based on the ultrasonic Doppler principle, the blood flow velocity module is a miniature ultrasonic transceiver, and the blood flow velocity analysis program specifically includes the following steps:

[0072] 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 θ. After the transmission wave enters the wearer's body, it becomes a reflected wave. The blood flow velocity module obtains the returned reflected wave. The blood flow velocity module subtracts the transmission wave from the reflected wave to obtain the Doppler shift frequency f3.

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

[0074] Step 303: The processing unit calculates the Calculate the blood flow velocity v in the wearer's body, δ is the propagation speed of the transmitted wave and the reflected wave in the wearer's body, generally 1540 m / s;

[0075] Step 304: The processing unit calculates the The first metabolic index dx1 of the wearer is calculated, where m is the weight information of the wearer, and the weight information is manually input into the processing unit in advance by the medical staff and saved.

[0076] The blood oxygen module consists of an infrared emitter and a photoelectric detector. The blood oxygen saturation analysis procedure specifically includes the following steps:

[0077] Step 305: The infrared transmitter sends infrared light into the wearer's body. After passing through the wearer's body, the infrared light is transformed into reflected infrared light and captured by the photoelectric detector. The blood oxygen module obtains the blood oxygen saturation xy according to the light intensity ratio of the transmitted infrared light and the received reflected infrared light. The formula is:

[0078] Step 306: The processing unit calculates the The wearer's second metabolic index dx2 is calculated, where age is the wearer's age information, which is manually input into the processing unit by medical staff in advance and saved. Δdx is the metabolic compensation value, and the specific value is determined according to the wearer's gender, which is 0.25 for males and 0.18 for females. The wearer's gender is also manually input into the processing unit by medical staff in advance.

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

[0080] Step 307: the processing unit controls the working frequency f4 of the gas flow module 3 to the first level, the body surface temperature and humidity module obtains the temperature tw1 and humidity ts1 of the wearer's body surface and transmits them to the processing unit, and the environment temperature and humidity module obtains 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 the second level, the body surface temperature and humidity module obtains the temperature tw2 and humidity ts2 of the wearer's body surface and transmits them to the processing unit, and the environment temperature and humidity module obtains 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 the third level, the body surface temperature and humidity module obtains the temperature tw3 and humidity ts3 of the wearer's body surface and transmits them to the processing unit, and the environment temperature and humidity module obtains the temperature hw3 and humidity hs3 of the environment and transmits them to the processing unit;

[0083] Step 310: The processing unit calculates the The wearer's third metabolic index dx3 is calculated.

[0084] Among them, Figure 2 As shown, the body surface temperature and humidity module and the ambient temperature and humidity module are both tubular structures in appearance. The outer layer of the tubular structure is a packaging tube shell 1, and the inner layer of the tubular structure is a silicon-based electrode 2. Air enters the tubular structure along direction A, and the silicon-based electrode 2 contacts the air to obtain temperature and humidity information. The air is then discharged along direction B, and one end of the air entering the tubular structure is connected to the gas flow module 3. The packaging tube shell 1 can improve the structural strength of the body surface temperature and humidity module and the ambient temperature and humidity module on the one hand, and increase durability. On the other hand, it can improve the efficiency of the contact between the silicon-based electrode 2 and the air, and improve the detection accuracy of the body surface temperature and humidity module and the ambient temperature and humidity module.

[0085] Among them, Figure 3-5 As shown, the gas flow module 3 includes a device housing 301, an air inlet 302 is opened on 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 opened at the center of the partition 303, the partition 303 separates a cavity 305 from the bottom of the device housing 301, an air outlet pipe 306 runs through one side of the device housing 301, the end of the air outlet pipe 306 facing the inside of the device housing 301 is connected to the cavity 305, and the end of the air outlet pipe 306 away from the cavity 305 is respectively connected to the body surface temperature and humidity module and the ambient temperature and humidity module;

[0086] 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, and the tops of the two bases 307 are fixedly connected to the top surface of the device housing 301. The first thin film metal 308 and the second thin film metal 310 are fixedly connected to the opposite sides of the two bases 307, and the first piezoelectric ceramic 309 is fixedly connected to the top of the first thin film metal 308, and the second piezoelectric ceramic 311 is fixedly connected to the top of the second thin film metal 310.

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

[0088] like 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, 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, and the second piezoelectric ceramic 311 is deformed and restored to drive the second thin film metal 310 to be in 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 its horizontal state and 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 pressure inside 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 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 housing 301. 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.

[0092] Through continuous circulation of the first stage and the second stage, the air sequentially flows out 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.

[0093] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A flexible microwave gas sensor for non-invasive blood glucose monitoring, characterized in that: It 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, a body surface detection unit, a processing unit, a gas flow module (3) and an environmental 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, and a user wears the annular protective shell on the arm to realize non-invasive blood sugar 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 sugar index c1; Step 2: The processing unit executes a microwave analysis program to obtain a second glycemic index c2; Step 3: 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; Step 4: The processing unit presets weight coefficients w1, w2 and w3, and 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.

2. A 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, the incident light intensity is I1, and the near infrared module obtains the near infrared light reflected by the wearer's body surface, 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 sends 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, the microwave module records the time t1 from sending to returning, and the microwave module transmits the time t1, the initial phase, the initial signal strength E and the specific frequency f to the processing unit; Step 202: The processing unit calculates the Calculate the phase of the returned microwave signal 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 The second blood sugar index c2 is calculated, where f1 is the specific frequency of the microwave signal, μ is the vacuum magnetic permeability, and the magnetic permeability in the human body is approximately the vacuum magnetic permeability μ, 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 θ. After the transmission wave enters the wearer's body, it becomes a reflected wave. The blood flow velocity module obtains the returned reflected wave. The blood flow velocity module subtracts the transmission wave from the reflected wave to obtain the Doppler shift frequency f3. Step 302: The blood flow velocity module transmits the transmission wave frequency f2, the angle θ and the Doppler shift frequency f3 to the processing unit; Step 303: According to the formula Calculate the blood flow velocity v in the wearer's body, δ is the propagation velocity of the transmitted wave and the reflected wave in the wearer's body; Step 304: According to the formula The first metabolic index dx1 of the wearer is calculated, where m is the weight information of the wearer.

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 procedure specifically 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 transformed into reflected infrared light and captured by the photoelectric detector. The blood oxygen module obtains the blood oxygen saturation xy according to 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 and Δdx is the metabolic compensation value, the specific value of which is determined according to the wearer's gender.

6. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The working frequency f4 of the gas flow module (3) is divided into a first level, a second level and a third level. The working 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 procedure specifically includes the following steps: Step 307: the processing unit controls the working 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 working 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 working 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.

7. 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 environment temperature and humidity module are both tubular structures in appearance, 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).

8. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 1, characterized in that: The gas flow module (3) comprises a device housing (301), the top of the device housing (301) is provided with an air inlet (302), 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 a cavity (305) from the bottom of the device housing (301), an air outlet pipe (306) passes through one side of the device housing (301), one end of the air outlet pipe (306) facing the inside of the device housing (301) is connected to the cavity (305), and one end of the air outlet pipe (306) away from the cavity (305) is respectively connected to the body surface temperature and humidity module and the environmental temperature and humidity module; Two bases (307) are fixedly connected to the two 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, and 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 the first thin film metal (308) and the second thin film metal (310), respectively. The top of the first thin film metal (308) is fixedly connected to the first piezoelectric ceramic (309), and the top of the second thin film metal (310) is fixedly connected to the second piezoelectric ceramic (311).

9. 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 when in 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 the positive electrode, 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, and the processing unit applies a pulsed unidirectional voltage to the second piezoelectric ceramic (311), the top of the second piezoelectric ceramic (311) is the negative electrode, 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; 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.

10. The flexible microwave gas sensor for non-invasive blood glucose monitoring according to claim 9, 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, 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, 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; 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 pressure inside 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 started again. 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 stage and the second stage, 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 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).

Images