A blood pressure detection device and method based on on-chip optical microcavity

Abstract

The present invention proposes a blood pressure detection device and method based on an on-chip optical microcavity, which relates to the technical field of blood pressure detection structure design. The on-chip optical microcavity is used to monitor the human radial artery pulse wave, making pulse detection more convenient and realizing the rapid acquisition of pulse wave signals. The pulse characteristic parameter points are then identified and analyzed, and the corresponding pulse-blood pressure model is fitted. Subsequently, only accurate pulse characteristic parameters need to be extracted with the support of the new on-chip optical microcavity sensor element, so as to accurately derive diastolic pressure, systolic pressure and mean pressure, providing an effective solution for non-invasive and convenient blood pressure monitoring and effective prevention of cardiovascular diseases.

Description

Technical Field

[0001] The present invention relates to the technical field of blood pressure detection structure design, and more specifically, to a blood pressure detection device and method based on an on-chip optical microcavity. Background Art

[0002] Blood pressure is a key physiological indicator of cardiovascular health and plays an important role in clinical diagnosis and monitoring. Therefore, accurate and convenient blood pressure monitoring is of great significance for preventing diseases such as hypertension.

[0003] Currently, common non-invasive blood pressure measurement methods include arterial tonometry, volume compensation, pulse wave velocity, and pulse wave characteristic parameter methods. The arterial tonometry method applies a certain pressure to the surface arteries to detect arterial pressure, obtain corresponding pressure data and waveform, and directly obtain the corresponding blood pressure value. This method places high demands on sensor accuracy and test process stability. The volume compensation method maintains a constant vascular volume by varying the applied pressure to match the arterial pressure. The applied pressure is equivalent to the arterial pressure. This method requires a large measurement device and a cumbersome and complex measurement process. The pulse wave velocity method first measures the pulse wave velocity and then indirectly calculates the blood pressure value. This method requires two measurement points on the body surface and calculates the pulse wave velocity by measuring the time the pulse wave travels at the two measurement points. Because this method involves two measurement points, the distance and time between the measurement points are difficult to precisely control, resulting in low measurement accuracy. The pulse wave characteristic parameter method measures the pulse wave waveform, extracts relevant characteristic parameters, and establishes a corresponding blood pressure model to accurately deduce blood pressure from the pulse wave. Although this method is an indirect measurement method, the main wave amplitude, dicrotic wave amplitude, descending isthmus amplitude, period, area and other relevant characteristic parameters of the pulse wave are closely related to the peripheral resistance of the blood vessels, vascular wall elasticity, blood viscosity and cardiac output. Therefore, the characteristic parameter method has a high degree of accuracy in estimating blood pressure and has been widely used and confirmed.

[0004] The prior art discloses a blood pressure monitoring device and method, which includes: a contact portion and a sensor module embedded in the contact portion. The sensor module is used to monitor the vibration caused by the heart of the subject propagating along the arterial blood vessels and blood flow to the periphery, and convert the vibration into an electrical signal. The sensor module includes two flexible films and an optical fiber sensor fixed in the two flexible films; it also includes a microprocessor connected to the sensor module, which is used to extract the pulse transmission time from the electrical signal, establish a blood pressure estimation model, and monitor the blood pressure in real time based on this blood pressure estimation model. The optical fiber sensor embedded in the contact part detects vibrations of the human body caused by the heart, which propagate along the arteries and blood flow to the periphery. It has high sensitivity and is resistant to electromagnetic interference. The user only needs to wear the contact part of the monitoring device on the relevant part of the human body or make contact with the relevant part of the human body to achieve real-time and continuous blood pressure monitoring. It has the advantages of compact structure, small size, easy portability, and simple operation. However, the optical fiber sensor in this solution has low sensitivity and signal-to-noise ratio to pulse vibrations, resulting in inaccurate identification of various characteristic parameter points of the pulse wave, such as the main wave, dicrotic wave, and descending isthmus, and the blood pressure detection accuracy is lacking.

[0005] In recent years, sensors based on on-chip optical microcavities have attracted widespread attention from researchers due to their small size, high sensitivity, high measurement accuracy, and low electromagnetic interference. Unlike traditional piezoelectric sensors, optical microcavity sensors are not affected by the sensing area, and their small size, measured in micrometers, allows for precise alignment of the radial artery at the wrist. Summary of the Invention

[0006] To solve the problem of how to use on-chip optical microcavities for blood pressure detection, the present invention proposes a blood pressure detection device and method based on on-chip optical microcavities. The on-chip optical microcavity sensor is used to monitor the radial artery pulse wave and derive blood pressure based on the pulse, providing an effective solution for non-invasive and convenient blood pressure monitoring and the prevention of cardiovascular diseases.

[0007] In order to achieve the above technical effects, the technical solutions of the present invention are as follows:

[0008] A blood pressure detection device based on an on-chip optical microcavity, the device comprising: a light source generating unit, an on-chip optical microcavity sensor element, a first signal processing unit, and a second signal processing unit connected in sequence; the light source generating unit generates a light signal, and a microring resonant cavity is provided in the on-chip optical microcavity sensor element; the blood pressure detection device further comprises a wavelength locking unit, which is connected to the light source generating unit and the on-chip optical microcavity sensor element respectively, and locks the output frequency of the light signal generated by the light source generating unit to a frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element, so that the light signal resonates in the microring resonant cavity; the on-chip optical microcavity sensor element is attached to the human pulse to receive the pulse The pressure transmitted by the beating produces a linearly corresponding drift of the resonant wavelength, forming a resonant wavelength variation; the first signal processing unit receives the optical signal output from the on-chip optical microcavity sensor element and the resonant wavelength variation in the on-chip optical microcavity sensor element, wherein the output power variation of the optical signal is linearly related to the resonant wavelength variation, forming a linear correspondence relationship of "human pulse pressure-resonant wavelength variation-optical signal output power". The first signal processing unit obtains the human pulse wave signal according to the output power of the optical signal and transmits it to the second signal processing unit. The second signal processing unit preprocesses the human pulse wave signal and identifies characteristic parameter points, and fits and establishes a pulse-blood pressure model.

[0009] This technical solution uses an on-chip optical microcavity to monitor the human radial artery pulse wave, making pulse detection more convenient and achieving rapid acquisition of pulse wave signals. It then identifies and analyzes pulse characteristic parameter points and fits the corresponding pulse-blood pressure model. Subsequently, it only needs to extract accurate pulse characteristic parameters with the support of the new on-chip optical microcavity sensor element to accurately derive diastolic pressure, systolic pressure and mean pressure, providing an effective solution for non-invasive and convenient blood pressure monitoring and effective prevention of cardiovascular diseases.

[0010] Preferably, the light source generating unit includes a continuous laser LASER and a polarization controller PC. The continuous laser LASER is connected to the polarization controller PC. The continuous laser LASER is used to generate single-frequency light of a certain frequency, and the polarization controller PC is used to process the single-frequency light into different polarization states.

[0011] Preferably, the on-chip optical microcavity sensor element includes a microring resonant cavity, a bus waveguide, and a substrate. The microring resonant cavity and the bus waveguide are both disposed in the substrate. The optical signal input to the optical microcavity sensor element is coupled into the microring resonant cavity in the form of an evanescent wave through the bus waveguide and resonates in the microring resonant cavity. After the on-chip optical microcavity sensor element receives the pressure transmitted by the pulse beating, the bus waveguide deforms, the field distribution changes, and the effective refractive index of the waveguide mode changes, resulting in a shift in the resonant wavelength, satisfying the following conditions:

[0012]

[0013] in, λ is the resonant wavelength of the microring resonator, Δ λ is the change in resonant wavelength, Δ l is the waveguide deformation caused by the pressure transmitted by the pulse beating, and the resonant wavelength change Δ λ、 Waveguide deformation Δ l、 There is a linear relationship between the pressure transmitted by the pulse beating. l is the total length of the original bus waveguide, Δn is the change in the waveguide refractive index, n is the refractive index of the original bus waveguide.

[0014] Here, there is a linear mathematical relationship between the change in resonant wavelength and pulse pressure.

[0015] Preferably, the on-chip optical microcavity sensor element is further provided with a PDMS soft contact layer, and the PDMS soft contact layer is arranged on the surface of the substrate.

[0016] Here, since the surface of human skin is not completely flat, if the on-chip optical microcavity sensor element is directly attached to the skin surface, it will not fit tightly, which will directly affect the pulse transmission effect. Adding a PDMS soft contact layer makes the on-chip optical microcavity sensor element fit more closely to the human skin, and the pressure transmission effect is better.

[0017] Preferably, the wavelength locking unit locks the output frequency of the optical signal generated by the light source generating unit to the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element, and the wavelength is locked to the side of the resonance peak of the microring resonant cavity. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, and determining the linear relationship between the human pulse pressure and the output power of the optical signal.

[0018] Here, by using the wavelength locking method, the laser output frequency is locked at the frequency corresponding to the wavelength at the half-width of the microring resonance peak. The change in the resonance wavelength can be linked to the output optical power, thereby ultimately achieving quantitative monitoring of the pulse signal.

[0019] Preferably, the first signal processing unit includes an erbium-doped fiber amplifier EDFA, a photodetector PD, a filter FILTER and an oscilloscope OSC connected in sequence. The erbium-doped fiber amplifier EDFA amplifies the optical power. Based on the linear correspondence of "human pulse pressure-resonance wavelength change-optical signal output power", the photodetector PD converts the optical signal into an electrical signal. The filter FILTER is a low-pass filter with a cutoff frequency of 30Hz, which is used to improve the signal-to-noise ratio of the signal. Finally, the human pulse wave signal is obtained according to the output power of the optical signal. The oscilloscope OSC is used to display the human pulse wave signal.

[0020] Preferably, the second signal processing unit pre-processes the human pulse wave signal by: performing digital filtering and high-frequency filtering on the human pulse wave signal, and performing baseline calibration of the human pulse wave signal by wavelet transform;

[0021] The threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, dicrotic wave and descending isthmus. Based on the identified characteristic parameter points, each characteristic parameter point is used as the dependent variable, and the diastolic pressure or systolic pressure is used as a separate variable. Regression analysis is performed using the regression analysis function regress to obtain the relationship expressions corresponding to the diastolic pressure and systolic pressure respectively, forming a pulse-blood pressure model.

[0022] This application also proposes a blood pressure detection method based on an on-chip optical microcavity, the blood pressure detection method comprising the following steps:

[0023] S1. Attach the on-chip optical microcavity sensor to the pulse of the human body to be detected;

[0024] S2. Use the wavelength locking unit to lock the output frequency of the optical signal generated by the light source generating unit to the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element. f At 0, the light source generating unit generates a specific frequency f 0 optical signal;

[0025] S3. The light signal is incident on the on-chip optical microcavity sensor element. Simultaneously, the on-chip optical microcavity sensor element receives the pressure transmitted by the pulse beating, generating a linear corresponding resonant wavelength drift, forming a resonant wavelength variation;

[0026] S4. Receive, using a first signal processing unit, an optical signal output from the on-chip optical microcavity sensor element and a change in the resonant wavelength within the on-chip optical microcavity sensor element, and determine, after locking the output frequency of the optical signal, a linear relationship between the change in the output power of the optical signal and the change in the resonant wavelength;

[0027] S5. Forming a linear correspondence between "human pulse pressure - resonant wavelength change - optical signal output power" and determining the human pulse wave signal based on the optical signal output power;

[0028] S6. Using the second signal processing unit to preprocess the human pulse wave signal and identify characteristic parameter points, and fit and establish a pulse - blood pressure model;

[0029] S7. Collect a new human pulse wave signal in the order of steps S1 to S5, input it into the pulse-blood pressure model, and obtain the systolic and diastolic blood pressure of the human body to be measured.

[0030] Preferably, in step S2, the wavelength locking unit locks the output frequency of the optical signal generated by the light source generating unit at the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element, and the wavelength is locked on the side of the resonance peak of the microring resonant cavity. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, determining the linear relationship between the human pulse pressure and the output power of the optical signal, and forming a linear correspondence of "human pulse pressure-resonance wavelength change-optical signal output power".

[0031] Preferably, in step S6, the threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, the dicrotic wave and the descending isthmus. Based on the identified characteristic parameter points, each characteristic parameter point is used as a dependent variable, and the diastolic pressure or the systolic pressure is used as a separate variable. Regression analysis is performed using the regression analysis function regress to obtain the relationship expressions corresponding to the diastolic pressure and the systolic pressure, respectively, to form a pulse-blood pressure model.

[0032] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0033] The present invention proposes a blood pressure detection device and method based on an on-chip optical microcavity. The on-chip optical microcavity is used to monitor the human radial artery pulse wave, making pulse detection more convenient and achieving rapid acquisition of pulse wave signals. The pulse characteristic parameter points are then identified and analyzed, and the corresponding pulse-blood pressure model is fitted. Subsequently, only accurate pulse characteristic parameters need to be extracted with the support of the new on-chip optical microcavity sensor element, thereby accurately deducing diastolic pressure, systolic pressure and mean pressure, providing an effective solution for non-invasive and convenient blood pressure monitoring and effective prevention of cardiovascular diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram showing the structure of a blood pressure detection device based on an on-chip optical microcavity proposed in Example 1 of the present invention;

[0035] Figure 2 A graph showing the mechanical transmission effect of different PDMS thicknesses proposed in Example 1 of the present invention;

[0036] Figure 3 A diagram showing the principle of wavelength locking performed by the wavelength locking unit proposed in Example 1 of the present invention;

[0037] Figure 4 A waveform comparison diagram showing the original optical signal power data and the optical signal power data after digital filtering proposed in Example 1 of the present invention;

[0038] Figure 5 A waveform diagram showing the data after baseline calibration and feature point parameter extraction proposed in Example 2 of the present invention;

[0039] Figure 6 A schematic diagram showing the flow of the blood pressure detection method based on an on-chip optical microcavity proposed in Example 3 of the present invention;

[0040] Among them, 1 is a light source generating unit; 2 is an on-chip optical microcavity sensor; 3 is a first signal processing unit; 4 is a second signal processing unit; 5 is a wavelength locking unit; 21 is a microring resonator; 22 is a bus waveguide; and 23 is a substrate. DETAILED DESCRIPTION

[0041] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting this patent;

[0042] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the actual size;

[0043] It is understandable to those skilled in the art that descriptions of certain well-known contents may be omitted in the drawings.

[0044] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0045] The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting this patent;

[0046] Example 1

[0047] like Figure 1As shown, this embodiment proposes a blood pressure detection device based on an on-chip optical microcavity, the device comprising: a light source generating unit 1, an on-chip optical microcavity sensor element 2, a first signal processing unit 3 and a second signal processing unit 4 connected in sequence; the light source generating unit 1 generates a light signal, and a microring resonant cavity is provided in the on-chip optical microcavity sensor element 2. The blood pressure detection device further comprises a wavelength locking unit 5, which is connected to the light source generating unit 1 and the on-chip optical microcavity sensor element 2 respectively, and locks the output frequency of the light signal generated by the light source generating unit 1 to the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element 2, so that the light signal resonates in the microring resonant cavity; the on-chip optical microcavity sensor element 2 is attached to the human body. On the pulse, the pressure transmitted by the pulse beat is received, and a linearly corresponding drift of the resonant wavelength is generated, forming a resonant wavelength variation; the first signal processing unit 3 receives the optical signal output from the on-chip optical microcavity sensor element 2 and the resonant wavelength variation in the on-chip optical microcavity sensor element 2, wherein the output power variation of the optical signal is linearly related to the resonant wavelength variation, forming a linear correspondence of "human pulse pressure-resonant wavelength variation-optical signal output power". The first signal processing unit 3 obtains the human pulse wave signal according to the output power of the optical signal and transmits it to the second signal processing unit 4. The second signal processing unit 4 preprocesses the human pulse wave signal and identifies characteristic parameter points, and fits and establishes a pulse-blood pressure model. The device uses an on-chip optical microcavity to monitor the human radial artery pulse wave, making pulse detection more convenient and realizing the rapid acquisition of pulse wave signals. It then identifies and analyzes the pulse characteristic parameter points and fits the corresponding pulse-blood pressure model. Subsequently, it only needs to extract accurate pulse characteristic parameters with the support of the new on-chip optical microcavity sensor element to accurately derive diastolic pressure, systolic pressure and mean pressure, providing an effective solution for non-invasive and convenient blood pressure monitoring and effective prevention of cardiovascular diseases.

[0048] See also Figure 1 The light source generating unit 1 includes a continuous laser LASER and a polarization controller PC. The continuous laser LASER is connected to the polarization controller PC. The continuous laser LASER is used to generate single-frequency light of a certain frequency, and the polarization controller PC is used to process the single-frequency light into different polarization states.

[0049] The on-chip optical microcavity sensor element 2 includes a microring resonant cavity 21, a bus waveguide 22, and a substrate 23. The microring resonant cavity 21 and the bus waveguide 22 are both arranged in the substrate. The optical signal input to the optical microcavity sensor element 2 is coupled into the microring resonant cavity in the form of an evanescent wave through the bus waveguide 22 and resonates in the microring resonant cavity 21. After the on-chip optical microcavity sensor element 2 receives the pressure transmitted by the pulse beating, the bus waveguide 22 is deformed, the field distribution changes, and the effective refractive index of the waveguide mode changes, resulting in a drift of the resonant wavelength, satisfying:

[0050]

[0051] in, λ is the resonant wavelength of the microring resonator, Δ λ is the change in resonant wavelength, Δ l is the waveguide deformation caused by the pressure transmitted by the pulse beating, and the resonant wavelength change Δ λ、 Waveguide deformation Δ l、 There is a linear relationship between the pressure transmitted by the pulse beating. l is the total length of the original bus waveguide, Δn is the change in the waveguide refractive index, n is the refractive index of the original bus waveguide.

[0052] Here, there is a linear mathematical relationship between the change in resonant wavelength and pulse pressure.

[0053] Since the surface of human skin is not completely flat, if the on-chip optical microcavity sensor element (2) is directly attached to the skin surface, it will not fit tightly, which will directly affect the pulse transmission effect. Adding a PDMS soft contact layer makes the on-chip optical microcavity sensor element fit more tightly to the human skin, and the pressure transmission effect is better. Therefore, the on-chip optical microcavity sensor element 2 is also provided with a PDMS soft contact layer, which is arranged on the surface of the substrate.

[0054] In this embodiment, the influence of different thicknesses of PDMS on the force transmission effect is simulated by finite element simulation software COMSOL. The results are as follows: Figure 3 As shown by Figure 3 It can be seen that the optimal thickness of the PDMS soft contact layer is about 1.01 mm. In the case of 1.01 mm PDMS, the on-chip optical microcavity has the best response to strain under the same pressure, that is, the highest response sensitivity.

[0055] In this embodiment, the wavelength locking unit 5 locks the output frequency of the optical signal generated by the light source generating unit 1 to the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element 2, such as Figure 4 As shown, the vertical axis represents the change in electric power. After passing through the photodetector PD, the optical power is reflected as electric power. The horizontal axis is time. The wavelength is locked on the side of the resonance peak of the microring resonator. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, and determining the linear relationship between the human pulse pressure and the output power of the optical signal.

[0056] Here, wavelength locking is used to lock the laser output frequency to the wavelength corresponding to the half-width at half-maximum of the microring resonance peak. This allows the change in resonant wavelength to be linked to the output optical power, ultimately enabling quantitative monitoring of the pulse signal. There's no specific calibration for how much pressure corresponds to how much drift, and because normalization is performed during processing, the specific calibration relationship is unimportant. The simulation result is 0.109 nm / MPa, a linear relationship between the two. This is difficult to quantitatively analyze, as the process response relationship is: "pressure → microring deformation → refractive index change → resonant wavelength change → output optical power change." The quantitative relationship from pressure to microring deformation is determined by the Young's modulus of the microring material, approximately 20 GPa. The deformation of the microring resonant cavity causes a change in refractive index, which is determined by the material's elasto-optical coefficient, p12 = 0.24. The quantitative relationship from refractive index change to resonant wavelength change is given by 2πnR = mλ, where n is the refractive index, R is the ring radius, λ is the wavelength, and m = 1, 2, or 3, integers.

[0057] See also Figure 1 The first signal processing unit 3 includes an erbium-doped fiber amplifier EDFA, a photodetector PD, a filter FILTER, and an oscilloscope OSC connected in sequence. The erbium-doped fiber amplifier EDFA amplifies the optical power. Based on the linear correspondence of "human pulse pressure-resonance wavelength change-optical signal output power", the photodetector PD converts the optical signal into an electrical signal. The filter FILTER is a low-pass filter with a cutoff frequency of 30Hz, which is used to improve the signal-to-noise ratio of the signal. Finally, a human pulse wave signal is obtained according to the output power of the optical signal. The oscilloscope OSC is used to display the human pulse wave signal.

[0058] Example 2

[0059] The second signal processing unit 4 pre-processes the human pulse wave signal by performing digital filtering and high-frequency filtering on the human pulse wave signal, and calibrating the baseline of the human pulse wave signal by wavelet transform. The result is as follows: Figure 5 shown.

[0060] The threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, dicrotic wave, and descending isthmus. Specifically, the raw optical power signal (corresponding to the pulse wave signal) is processed using MATLAB software. Because baseline drift is inevitable during pulse wave acquisition, the raw data is first baseline-calibrated using wavelet analysis. Maximum and minimum values are identified through quadratic difference analysis. Then, by setting thresholds, specific maximum and minimum points in the pulse signal are identified. The horizontal and vertical coordinates of these extreme points represent important characteristic parameter points of the pulse wave. Based on the identified characteristic parameter points, each characteristic parameter point is used as the dependent variable, and diastolic or systolic blood pressure is used as the independent variable. Regression analysis is performed using the regression function regress to obtain the corresponding relationship expressions for diastolic and systolic blood pressure, respectively, forming a pulse-blood pressure model.

[0061] Example 3

[0062] like Figure 6 As shown, this embodiment proposes a blood pressure detection method based on an on-chip optical microcavity, and the blood pressure detection method includes the following steps:

[0063] S1. Attach the on-chip optical microcavity sensor element 2 to the pulse of the human body to be detected;

[0064] S2. Use the wavelength locking unit 5 to lock the output frequency of the optical signal generated by the light source generating unit 1 to the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element 2. f 0, the light source generating unit 1 generates a specific frequency f 0 optical signal;

[0065] S3. The optical signal is incident on the on-chip optical microcavity sensor element 2. At the same time, the on-chip optical microcavity sensor element 2 receives the pressure transmitted by the pulse beating, generating a linear corresponding resonant wavelength drift, forming a resonant wavelength change;

[0066] S4. Using the first signal processing unit 3 to receive the optical signal output from the on-chip optical microcavity sensor element 2 and the change in the resonant wavelength within the on-chip optical microcavity sensor element 2, after locking the output frequency of the optical signal, determine the linear relationship between the change in the output power of the optical signal and the change in the resonant wavelength;

[0067] S5. Forming a linear correspondence between "human pulse pressure - resonant wavelength change - optical signal output power" and determining the human pulse wave signal based on the optical signal output power;

[0068] S6. Using the second signal processing unit 4, the human pulse wave signal is preprocessed and the characteristic parameter points are identified, and a pulse-blood pressure model is fitted and established;

[0069] S7. Collect a new human pulse wave signal in the order of steps S1 to S5, input it into the pulse-blood pressure model, and obtain the systolic and diastolic blood pressure of the human body to be measured.

[0070] In step S2, the wavelength locking unit 5 locks the output frequency of the optical signal generated by the light source generating unit 1 at the frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element 2. The wavelength is locked on the side of the resonance peak of the microring resonant cavity. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, determining the linear relationship between the human pulse pressure and the output power of the optical signal, and forming a linear correspondence of "human pulse pressure-resonance wavelength change-optical signal output power".

[0071] In step S6, the threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, the dicrotic wave and the descending isthmus. Based on the identified characteristic parameter points, each characteristic parameter point is used as the dependent variable, and the diastolic pressure or the systolic pressure is used as a separate variable. Regression analysis is performed using the regression analysis function regress to obtain the relationship expressions corresponding to the diastolic pressure and the systolic pressure, respectively, to form a pulse-blood pressure model.

[0072] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A blood pressure detection device based on an on-chip optical microcavity, characterized in that: The device comprises: a light source generating unit (1), an on-chip optical microcavity sensor element (2), a first signal processing unit (3) and a second signal processing unit (4) connected in sequence; the light source generating unit (1) generates a light signal, and a microring resonant cavity is provided in the on-chip optical microcavity sensor element (2); the blood pressure detection device further comprises a wavelength locking unit (5), and the wavelength locking unit (5) is respectively connected to the light source generating unit (1) and the on-chip optical microcavity sensor element (2), and locks the output frequency of the light signal generated by the light source generating unit (1) at a frequency corresponding to the half-width wavelength of the microring resonant cavity of the on-chip optical microcavity sensor element (2), so that the light signal resonates in the microring resonant cavity; the on-chip optical microcavity sensor element (2) is attached to the human pulse and receives the light signal. The pressure transmitted by the pulse beat generates a linearly corresponding drift of the resonant wavelength, forming a resonant wavelength variation; the first signal processing unit (3) receives the optical signal output from the on-chip optical microcavity sensor element (2) and the resonant wavelength variation in the on-chip optical microcavity sensor element (2), wherein the output power variation of the optical signal is linearly related to the resonant wavelength variation, forming a linear correspondence relationship of "human pulse pressure-resonant wavelength variation-optical signal output power", the first signal processing unit (3) obtains the human pulse wave signal according to the output power of the optical signal, and transmits it to the second signal processing unit (4), the second signal processing unit (4) performs preprocessing and characteristic parameter point identification on the human pulse wave signal, and fits and establishes a pulse-blood pressure model; The on-chip optical microcavity sensor element (2) includes a microring resonant cavity (21), a bus waveguide (22) and a substrate (23). The microring resonant cavity (21) and the bus waveguide (22) are both arranged in the substrate. The optical signal input to the optical microcavity sensor element (2) is coupled into the microring resonant cavity in the form of an evanescent wave through the bus waveguide (22) and resonates in the microring resonant cavity (21). After the on-chip optical microcavity sensor element (2) receives the pressure transmitted by the pulse beating, the bus waveguide is deformed, the field distribution is changed, and the effective refractive index of the waveguide mode is changed, resulting in a drift of the resonant wavelength, satisfying: in, λ is the resonant wavelength of the microring resonator, Δ λ is the change in resonant wavelength, Δ l is the waveguide deformation caused by the pressure transmitted by the pulse beating, and the resonant wavelength change Δ λ、 Waveguide deformation Δ l、 There is a linear relationship between the pressure transmitted by the pulse beating. l is the total length of the original bus waveguide, Δn is the change in the waveguide refractive index, n is the refractive index of the original bus waveguide; The on-chip optical microcavity sensor element (2) is further provided with a PDMS soft contact layer, and the PDMS soft contact layer is provided on the surface of the substrate; The wavelength locking unit (5) locks the output frequency of the optical signal generated by the light source generating unit (1) at the frequency corresponding to the half-width wavelength of the micro-ring resonant cavity of the on-chip optical micro-cavity sensor (2). The wavelength is locked on the side of the resonance peak of the micro-ring resonant cavity. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, and determining the linear relationship between the human pulse pressure and the output power of the optical signal. The first signal processing unit (3) includes an erbium-doped fiber amplifier EDFA, a photodetector PD, a filter FILTER and an oscilloscope OSC connected in sequence. The erbium-doped fiber amplifier EDFA amplifies the optical power. Based on the linear correspondence of "human pulse pressure-resonance wavelength change-optical signal output power", the photodetector PD converts the optical signal into an electrical signal. The filter FILTER is a low-pass filter with a cutoff frequency of 30 Hz, which is used to improve the signal-to-noise ratio of the signal. Finally, a human pulse wave signal is obtained according to the output power of the optical signal. The oscilloscope OSC is used to display the human pulse wave signal. The second signal processing unit (4) pre-processes the human pulse wave signal by performing digital filtering and high-frequency filtering on the human pulse wave signal, and performing baseline calibration of the human pulse wave signal by wavelet transformation; The threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, dicrotic wave and descending isthmus. Based on the identified characteristic parameter points, each characteristic parameter point is used as the dependent variable, and the diastolic pressure or systolic pressure is used as a separate variable. Regression analysis is performed using the regression analysis function regress to obtain the relationship expressions corresponding to the diastolic pressure and systolic pressure respectively, forming a pulse-blood pressure model.

2. The blood pressure detection device based on an on-chip optical microcavity according to claim 1, characterized in that: The light source generating unit (1) comprises a continuous laser LASER and a polarization controller PC. The continuous laser LASER is connected to the polarization controller PC. The continuous laser LASER is used to generate single-frequency light of a certain frequency, and the polarization controller PC is used to process the single-frequency light into different polarization states.

3. A blood pressure detection method based on an on-chip optical microcavity, characterized in that: The blood pressure detection method is used to implement the blood pressure detection device based on an on-chip optical microcavity according to any one of claims 1 to 2, comprising the following steps: S1. attaching the on-chip optical microcavity sensor element (2) to the pulse of the human body to be detected; S2. Use the wavelength locking unit (5) to lock the output frequency of the optical signal generated by the light source generating unit (1) to the frequency corresponding to the half-width wavelength of the micro-ring resonant cavity of the on-chip optical micro-cavity sensor element (2) f At 0, the light source generating unit (1) generates a specific frequency f 0 optical signal; S3. The optical signal is incident on the on-chip optical microcavity sensor element (2), and at the same time, the on-chip optical microcavity sensor element (2) receives the pressure transmitted by the pulse beating, generating a linear corresponding resonant wavelength drift, forming a resonant wavelength variation; S4. using the first signal processing unit (3) to receive the optical signal output from the on-chip optical microcavity sensor element (2) and the change in the resonant wavelength within the on-chip optical microcavity sensor element (2), and after locking the output frequency of the optical signal, determining the linear relationship between the change in the output power of the optical signal and the change in the resonant wavelength; S5 forms a linear correspondence between "human pulse pressure - resonant wavelength change - optical signal output power" and determines the human pulse wave signal based on the optical signal output power; S6. Using the second signal processing unit (4) to preprocess the human pulse wave signal and identify characteristic parameter points, and to fit and establish a pulse-blood pressure model; S7. Collect a new human pulse wave signal in the order of steps S1 to S5, input it into the pulse-blood pressure model, and obtain the systolic and diastolic blood pressure of the human body to be measured.

4. The blood pressure detection method based on an on-chip optical microcavity according to claim 3, characterized in that: In step S2, the wavelength locking unit (5) locks the output frequency of the optical signal generated by the light source generating unit (1) at the frequency corresponding to the half-width wavelength of the micro-ring resonant cavity of the on-chip optical micro-cavity sensor (2), and the wavelength is locked on the side of the resonance peak of the micro-ring resonant cavity. The quantitative relationship between the output power of the optical signal and the change in the resonance wavelength depends on the Q value of the resonance peak. The Q value of the resonance peak reflects the slope of the resonance peak. When the resonance wavelength changes, the optical power corresponding to the fixed wavelength changes accordingly, thereby converting the change in the resonance peak into a change in the output power of the optical signal, determining the linear relationship between the human pulse pressure and the output power of the optical signal, and forming a linear corresponding relationship of "human pulse pressure-resonance wavelength change-optical signal output power".

5. The blood pressure detection method based on an on-chip optical microcavity according to claim 4, characterized in that: In step S6, the threshold difference method is used to identify the characteristic parameter points of the human pulse wave signal, including the main wave, the dicrotic wave and the descending isthmus. Based on the identified characteristic parameter points, each characteristic parameter point is used as the dependent variable, and the diastolic pressure or the systolic pressure is used as a separate variable. Regression analysis is performed using the regression analysis function regress to obtain the relationship expressions corresponding to the diastolic pressure and the systolic pressure, respectively, to form a pulse-blood pressure model.

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