Blood pressure monitoring method and device

Abstract

The invention provides a blood pressure monitoring method and a blood pressure monitoring device. The blood pressure monitoring method comprises the following steps: monitoring a vibration signal vertical to the skin surface caused by pulse waves of a to-be-monitored object; determining a pulse wave signal of the to-be-detected object according to the vibration signal; according to a transfer function and the pulse wave signal, a blood pressure wave signal of the to-be-detected object is determined, and the transfer function represents the mapping relation between the pulse wave signal and the blood pressure wave signal. The measuring direction is set to be the out-of-plane vibration direction perpendicular to the skin surface, motion artifact interference introduced by in-plane vibration such as skin stretching or contraction caused by external force is avoided, effective decoupling of motion artifacts is achieved, and the blood pressure monitoring precision in the dynamic environment is improved.

Description

Technical Field

[0001] This disclosure relates to the field of blood pressure monitoring technology, and in particular to a blood pressure monitoring method and a blood pressure monitoring device. Background Technology

[0002] In the field of blood pressure monitoring technology, traditional cuff-type blood pressure monitors mainly rely on Korotkoff sound auscultation or oscillometric methods to achieve intermittent measurement. This measurement method obtains blood pressure values ​​through periodic inflation, which makes it impossible to obtain continuous blood pressure data. Therefore, it cannot track blood pressure fluctuations over a long period of time, and the inflation process causes discomfort when wearing the monitor.

[0003] With the development of microelectronics and sensing technologies, non-invasive continuous blood pressure monitoring technologies have emerged, such as optical detection technology, finger-clip measurement technology, wrist measurement technology, flat compression technology, and piezoelectric sensing technology. However, in practical applications, motion interference often leads to difficulties in ensuring the accuracy of blood pressure measurements. Summary of the Invention

[0004] This disclosure provides a blood pressure monitoring method and a blood pressure monitoring device.

[0005] In a first aspect, embodiments of this disclosure provide a blood pressure monitoring method, comprising: monitoring a vibration signal perpendicular to the skin surface caused by the pulse wave of a subject; determining the pulse wave signal of the subject based on the vibration signal; and determining the blood pressure wave signal of the subject based on a transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

[0006] In some embodiments, monitoring a vibration signal perpendicular to the skin surface caused by the pulse wave of the object under test includes: detecting the pressure of the pulse wave using a pressure sensing element and converting it into vibration of the pressure sensing element, wherein the pressure sensing element has high in-plane stiffness and low normal stiffness; monitoring the vibration of the pressure sensing element and determining the vibration signal.

[0007] In some embodiments, monitoring the vibration of the pressure sensing element and determining the vibration signal includes: splitting an input laser into a reference light and a measurement light; irradiating the pressure sensing element with the measurement light to obtain reflected light; performing multimode interference between the reference light and the reflected light to obtain multiple interference beams, wherein the multiple interference beams have a fixed phase difference; and determining the vibration signal based on the multiple interference beams.

[0008] In some embodiments, determining the blood pressure wave signal of the test subject based on the transfer function and the pulse wave signal includes: acquiring the calibrated pulse wave signal and the calibrated blood pressure wave signal of the test subject; analyzing the calibrated pulse wave signal and the calibrated blood pressure wave signal to obtain the transfer function of the test subject; and obtaining the blood pressure wave signal based on the transfer function and the pulse wave signal.

[0009] In some embodiments, analyzing the calibrated pulse wave signal and the calibrated blood pressure wave signal to obtain the transfer function of the test object includes: extracting morphological features from the calibrated pulse wave signal, wherein the morphological features include at least one of the following: the peak value of the main wave reflecting systolic pressure, the height and position of the tidal wave and dicrotic wave reflecting vascular tension and elasticity, the pulse cycle, the time of the main wave in the pulse cycle, the time of the tidal wave in the pulse cycle, and the time of the dicrotic wave in the pulse cycle; determining the mapping relationship between the morphological features and the blood pressure value; and determining the transfer function based on the calibrated pulse wave signal, the calibrated blood pressure wave signal, and the mapping relationship.

[0010] Secondly, embodiments of this disclosure provide a blood pressure monitoring device, comprising: a vibration monitoring module for monitoring vibration signals perpendicular to the skin surface caused by the pulse wave of a test subject; a pulse wave signal detection module for determining the pulse wave signal of the test subject based on the vibration signal; and a blood pressure wave signal detection module for determining the blood pressure wave signal of the test subject based on a transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

[0011] In some embodiments, the vibration monitoring module includes: a pressure detection element having high in-plane stiffness and low normal stiffness, used to convert the pressure of a pulse wave into vibration of the pressure detection element; and a vibration monitoring unit used to monitor the vibration of the pressure detection element and determine the vibration signal.

[0012] In some embodiments, the vibration monitoring unit includes: a laser for providing input laser light; an optical fiber coupler for splitting the input laser light into a reference light and a measurement light; an output structure for illuminating the pressure detection element with the measurement light and collecting the reflected light from the pressure detection element; an N×N optical coupler for interfering the input reference light and the reflected light to obtain multiple interference lights, wherein the multiple interference lights have a fixed phase difference, and N is an integer not less than 2; a photodetector for converting the multiple interference lights into electrical signals to obtain multiple electrical signals; and a signal processing unit for generating the vibration signal based on the multiple electrical signals.

[0013] In some embodiments, the exit structure includes a gradient refractive index lens or a convex lens group.

[0014] In some embodiments, the blood pressure monitoring device further includes a frequency shifter, the two ends of which are connected to the fiber optic coupler and the N×N optical coupler, respectively, for shifting the reference light.

[0015] The blood pressure monitoring method of this disclosure determines the pulse wave signal by monitoring the vibration signal perpendicular to the skin surface caused by the pulse wave of the subject. Based on the transfer function characterizing the mapping relationship between the pulse wave signal and the blood pressure wave signal, and the pulse wave signal itself, the blood pressure wave signal of the subject is determined, thus realizing a vibration measurement method based on the out-of-plane direction. By setting the measurement direction to an out-of-plane vibration direction perpendicular to the skin surface, motion artifact interference introduced by in-plane vibrations such as skin stretching or contraction caused by external forces is avoided, effectively decoupling motion artifacts and improving the accuracy of blood pressure monitoring in dynamic environments. Attached Figure Description

[0016] Figure 1 This is a flowchart of a blood pressure monitoring method according to an embodiment of this disclosure.

[0017] Figure 2 This is a schematic diagram illustrating the mapping principle between pulse wave signals and blood pressure signals in an embodiment of this disclosure.

[0018] Figure 3 This is the pulse wave vibration measurement result of a blood pressure monitoring device under different measurement states in an embodiment of this disclosure.

[0019] Figure 4 This is a schematic block diagram of a blood pressure monitoring device according to an embodiment of this disclosure.

[0020] Figure 5 This is a schematic diagram of the overall architecture of a blood pressure monitoring device according to an embodiment of this disclosure.

[0021] Figure 6 This is a schematic diagram of the vibration monitoring unit of a blood pressure monitoring device according to an embodiment of the present disclosure.

[0022] Figure 7 This is a blood pressure monitoring and measurement system according to an embodiment of the present disclosure.

[0023] Figure 8 This is another blood pressure monitoring and measurement system in the embodiments of this disclosure. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of this disclosure, the technical solutions of this disclosure will be described in detail below with reference to the accompanying drawings.

[0025] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0026] Where there is no conflict, the various embodiments of this disclosure and the features thereof in the embodiments may be combined with each other.

[0027] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0029] Unless otherwise specified in this disclosure, the following technical terms shall be interpreted as follows: In-face vibration refers to the periodic movement of blood vessel walls parallel to the skin surface, caused by the heartbeat.

[0030] Out-of-face vibration refers to the periodic movement of blood vessel walls perpendicular to the skin surface, caused by the heartbeat.

[0031] High in-plane stiffness refers to the fact that the structure is difficult to stretch, compress or deform in the direction parallel to the surface of the component (XY direction), and can suppress motion disturbances in the XY direction.

[0032] Low normal stiffness refers to the direction perpendicular to the surface of the component (normal or Z direction), which is extremely sensitive to external forces. The structure is relatively easy to bend or displace and can respond with high sensitivity to vibrations in the Z direction.

[0033] Zero-difference interferometry refers to the use of a single-frequency laser as a light source, in which the displacement or vibration information of the object under test is entirely contained in the changes in light intensity and phase generated by interference.

[0034] Heterodyne interferometry refers to the use of two lasers with slightly different frequencies as light sources. When these two beams interfere, they generate a beat frequency signal. The motion information of the object under test is modulated onto the phase of this beat frequency signal. By detecting the phase change, the magnitude and direction of the displacement can be directly calculated.

[0035] Blood pressure measurement technologies such as optical detection, finger-type measurement, wrist-type measurement, flat-press measurement, and piezoelectric sensing generally employ large-area surface contact to mechanically constrain the sensing unit to the skin surface, capturing the micro-pressure signals generated by the pulse wave. However, during actual wear, human movement causes instantaneous changes in hemodynamic parameters and skin and muscle stress, leading to a redistribution of the vascular wall stress field and altering the mechanical coupling state between the sensor and the body surface. The multidimensional perturbations generated by movement are transmitted through the sensor... Biomechanical coupling paths embed real pulse wave signals in a nonlinear manner, creating motion artifacts. These artifacts manifest as waveform feature shifts and harmonic distortions, introducing systematic errors into pulse wave-based blood pressure prediction models and making it difficult to guarantee signal reliability and measurement accuracy.

[0036] The inventors discovered that motion artifacts mainly interfere with in-plane vibrations in the XY direction, while having less interference with out-of-plane vibrations in the Z direction. Breaking through the traditional "surface contact" mode, the laser "point contact" measurement method, which is insensitive to the direction and amplitude of motion loads, can effectively decouple in-plane motion artifacts from out-of-plane vibration signals and significantly reduce interference introduced by changes in large-area contact interfaces.

[0037] In view of this, the present disclosure provides a non-contact, artifact-free, and high-precision continuous blood pressure monitoring device, which aims to solve the problems of phase distortion, waveform feature shift and harmonic component distortion caused by the difficulty in decoupling motion artifacts in in-plane measurement methods.

[0038] Figure 1 This is a flowchart of a blood pressure monitoring method according to an embodiment of this disclosure.

[0039] Firstly, referring to Figure 1 This disclosure provides a blood pressure monitoring method, including: S11. Monitor the vibration signal perpendicular to the skin surface caused by the pulse wave of the subject under test; S12. Determine the pulse wave signal of the object under test based on the vibration signal; S13. Determine the blood pressure wave signal of the test subject based on the transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

[0040] This embodiment employs a non-contact measurement method. It determines the pulse wave signal by monitoring the vibration signal perpendicular to the skin surface caused by the pulse wave of the test object. Based on the transfer function characterizing the mapping relationship between the pulse wave signal and the blood pressure wave signal, and the pulse wave signal itself, the blood pressure wave signal of the test object is determined, thus achieving a vibration measurement method based on the out-of-plane direction. By setting the measurement direction to an out-of-plane vibration direction perpendicular to the skin surface, motion interference introduced by in-plane vibrations such as skin stretching or contraction caused by external forces is avoided, thereby effectively decoupling motion artifacts.

[0041] This disclosure does not specifically limit the device used to implement the above-described blood pressure monitoring method. In some embodiments, the above-described blood pressure monitoring method is a blood pressure monitoring method applied to a wearable device.

[0042] In some embodiments, monitoring a vibration signal perpendicular to the skin surface caused by the pulse wave of the object under test includes: detecting the pressure of the pulse wave using a pressure sensing element and converting it into vibration of the pressure sensing element, wherein the pressure sensing element has high in-plane stiffness and low normal stiffness; monitoring the vibration of the pressure sensing element and determining the vibration signal.

[0043] In the embodiments of this disclosure, the pressure sensing element includes a patch structure with high in-plane stiffness and low normal stiffness or other structural elements with high in-plane stiffness and low normal stiffness, and this disclosure does not impose any special limitations on it.

[0044] In this embodiment, the pressure of the pulse wave is converted into the vibration of a pressure sensing element, and the vibration of the pressure sensing element is then monitored to determine the vibration signal. The pressure sensing element employs a micro-dynamic design with high in-plane stiffness and low normal stiffness; its in-plane stiffness is significantly higher than its normal stiffness. Compared to vibrations in the XY directions, the pressure sensing element is more sensitive to minute vibrations in the Z direction. Since motion artifacts mainly manifest as interference from in-plane pulse vibrations in the XY directions, while interference from out-of-plane pulse vibrations in the Z direction is relatively small, motion artifact interference in the XY directions can be effectively suppressed. This achieves effective decoupling of motion artifacts at the physical level, ensuring that the vibration signal obtained by converting the out-of-plane pressure of the pulse wave using the pressure monitoring element primarily carries out-of-plane vibration information synchronized with the pulse.

[0045] This disclosure does not impose any particular limitation on how the vibration of the pressure sensing element is monitored to determine the vibration signal. Any method or apparatus capable of performing micro-vibration measurement can be used to monitor the vibration of the pressure sensing element.

[0046] In some embodiments, a phase demodulation method based on zero-difference interferometry is used to monitor the vibration of a pressure sensing element.

[0047] In some embodiments, monitoring the vibration of the pressure sensing element and determining the vibration signal includes: splitting an input laser into a reference light and a measurement light; irradiating the pressure sensing element with the measurement light to obtain reflected light; performing multimode interference between the reference light and the reflected light to obtain multiple interference beams, wherein the multiple interference beams have a fixed phase difference; and determining the vibration signal based on the multiple interference beams.

[0048] In this embodiment, the input laser is split into a reference beam and a measurement beam. The reference beam maintains a fixed optical path, while the measurement beam guides a pressure detection element to obtain reflected light. Out-of-plane vibration signals can be captured by sensing minute optical path changes induced by dynamic physiological vibrations. By performing multimode interference between the reference beam and the reflected beam, multi-path interference beams with a fixed phase difference can be obtained. This phase difference is caused by minute optical path changes induced by out-of-plane vibrations, and the phase difference relationship can reflect vibration information. Therefore, vibration information can be determined without an external reference beam or spectral scanning, ensuring measurement stability and high accuracy.

[0049] Figure 2 This is a schematic diagram illustrating the mapping principle between pulse wave signals and blood pressure signals in an embodiment of this disclosure. Figure 3 This is the pulse wave vibration measurement result of a blood pressure monitoring device under different measurement states in an embodiment of this disclosure.

[0050] The morphology, propagation speed, and amplitude of the pulse wave are determined by the dynamics of the blood pressure wave. Changes in blood pressure directly cause changes in the pulse wave morphology. By extracting morphological features related to blood pressure, a mapping relationship between the pulse wave and the blood pressure wave can be established. Since the pulse wave and blood pressure wave are correlated and dependent in both the time domain and morphology, the transfer function, which characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal, can be used to infer the blood pressure wave signal from the detected pulse wave signal.

[0051] In this embodiment, the transfer function can be pre-set in the blood pressure monitoring device, or it can be a personalized transfer function obtained during the calibration phase by collecting and analyzing the calibration pulse wave signal and calibration blood pressure wave signal of the subject. This embodiment does not impose any special limitations on this.

[0052] In some embodiments, analyzing the calibrated pulse wave signal and the calibrated blood pressure wave signal to obtain the transfer function of the test object includes: extracting morphological features from the calibrated pulse wave signal, wherein the morphological features include at least one of the following: the peak value of the main wave reflecting systolic pressure, the height and position of the tidal wave and dicrotic wave reflecting vascular tension and elasticity, the pulse cycle, the time of the main wave in the pulse cycle, the time of the tidal wave in the pulse cycle, and the time of the dicrotic wave in the pulse cycle; determining the mapping relationship between the morphological features and the blood pressure value; and determining the transfer function based on the calibrated pulse wave signal, the calibrated blood pressure wave signal, and the mapping relationship.

[0053] In some embodiments, a transfer function is determined during the calibration phase, and based on this transfer function and the pulse wave signal, a blood pressure wave signal of the test subject is determined, including: acquiring a calibrated pulse wave signal and a calibrated blood pressure wave signal of the test subject; analyzing the calibrated pulse wave signal and the calibrated blood pressure wave signal to obtain the transfer function of the test subject; and obtaining the blood pressure wave signal based on the transfer function and the pulse wave signal.

[0054] For example, refer to Figure 2 Multiple morphological feature points are extracted from a single pulse beat, and a mapping relationship is analyzed based on pulse wave morphology. These morphological feature points include the main peak value that indicates systolic pressure. The height and position of tidal waves and dicrotic waves, reflecting vascular tension and elasticity. pulse cycle The duration of the main wave, tidal wave, and diphthous wave throughout the entire pulse cycle Isoparametric features. Constructing a complex mapping model between these morphological feature points and blood pressure values ​​using mapping functions. During calibration, the synchronously acquired pulse wave and blood pressure wave signals are subjected to frequency domain mathematical analysis using a mapping function to calculate the transfer function connecting the pulse wave and blood pressure wave signals. The formula for obtaining the blood pressure wave signal from the pulse wave signal using the calculated transfer function is as follows: , in It is the frequency domain representation of the blood pressure wave. It is the frequency domain representation of the pulse wave. It is a transfer function.

[0055] Reference Figure 3By analyzing pulse wave signals under different conditions, even in the presence of external motion interference due to limb movements such as hand movements, the key feature points of the pulse wave signals detected in steps S11 to S12 remain clear and show no significant distortion. This result directly verifies that the present disclosure can effectively decouple motion interference from pulse wave signals, and can be applied to improve the accuracy of blood pressure measurement in dynamic scenarios.

[0056] Figure 4 This is a schematic block diagram of a blood pressure monitoring device according to an embodiment of this disclosure. Figure 5 This is a schematic diagram of the overall architecture of a blood pressure monitoring device according to an embodiment of this disclosure. Figure 6 This is a schematic diagram of the vibration monitoring unit of a blood pressure monitoring device according to an embodiment of the present disclosure.

[0057] Secondly, referring to Figure 4 , Figure 5 This disclosure provides a blood pressure monitoring device, comprising: a vibration monitoring module 11 for monitoring vibration signals perpendicular to the skin surface caused by the pulse wave of a test subject; a pulse wave signal detection module 12 for determining the pulse wave signal of the test subject based on the vibration signal; and a blood pressure wave signal detection module 13 for determining the blood pressure wave signal of the test subject based on a transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

[0058] This disclosure does not specifically limit the blood pressure monitoring device. In some embodiments, the blood pressure monitoring device is a wearable device, such as a smartwatch or wristband.

[0059] In some embodiments, the vibration monitoring module 11 includes: a pressure detection element 4 having high in-plane stiffness and low normal stiffness, used to convert the pressure of the pulse wave into vibration of the pressure detection element 4; and a vibration monitoring unit used to monitor the vibration of the pressure detection element 4 and determine the vibration signal.

[0060] In some embodiments, the vibration monitoring unit includes: a laser 1 for providing input laser light; an optical fiber coupler 2 for splitting the input laser light into a reference light and a measurement light; an output structure 3 for irradiating the pressure detection element 4 with the measurement light and collecting the reflected light from the pressure detection element 4; an N×N optical coupler 5 for interfering the input reference light and the reflected light to obtain multiple interference lights, wherein the multiple interference lights have a fixed phase difference, and N is an integer not less than 2; a photodetector 6 for converting the multiple interference lights into electrical signals to obtain multiple electrical signals; and a signal processing unit 7 for generating vibration signals based on the phase demodulation of the multiple electrical signals.

[0061] In the embodiments disclosed herein, such as Figure 5 As shown, the blood pressure monitoring device of this embodiment includes a laser 1 for generating input laser light, an optical fiber coupler 2, an output structure 3, a pressure detection element 4, an N×N optical coupler 5, a photodetector 6, and a signal processing unit 7. The optical fiber coupler 2 is connected to the laser 1 and splits the input laser light into a reference light and a measurement light. The reference light is used to maintain a fixed optical path. The output structure 3 irradiates the pressure detection element 4 with the measurement light, forming reflected light. The reflected light includes optical path changes caused by out-of-plane vibrations. The N×N optical coupler 5 is connected to both the optical fiber coupler 2 and the output structure 3, allowing the reference light and reflected light to enter the N×N optical coupler 5. The reference light and reflected light interfere and superimpose in the N×N optical coupler 5, generating multiple interference lights with a fixed phase difference. The photodetector 6 converts the multiple interference lights into electrical signals. For example, in some embodiments, the photodetector 6 corresponds one-to-one with the N output ports of the N×N optical coupler 5, converting the N interference light signals (… , , ..., The signal is converted into N corresponding electrical signals. The signal processing unit 7 is connected to the N×N optical coupler 5. The signal processing unit 7 performs phase demodulation on the interference signal and maps it to obtain the blood pressure wave waveform.

[0062] In this embodiment of the disclosure, laser 1 is used to generate a stable and continuous input laser light and couple the input laser light to fiber coupler 2. The laser in this embodiment of the disclosure can be any device capable of generating stable and continuous light, such as a laser diode, etc., and this disclosure does not impose any special limitations on it.

[0063] In this embodiment of the disclosure, the fiber optic coupler 2 is used to split the input laser generated by the laser 1 into N optical signals. In some embodiments, the fiber optic coupler 2 is a 1×2 fiber optic coupler. This 1×2 fiber optic coupler splits the input laser into a reference light and a measurement light. The reference light maintains a fixed optical path, and the measurement light is guided by the pressure detection element 4 to obtain the reflected light. It can capture out-of-plane vibration signals by sensing minute changes in optical path caused by dynamic physiological vibrations.

[0064] In some embodiments, such as Figure 6 As shown, the emission structure 3 of the vibration monitoring unit also includes a measuring arm 301 and a light return collection structure 302. The pressure detection element is a patch structure 401. The measuring arm 301 guides the measuring light to the patch structure 401, and the light return collection structure 302 receives the reflected light obtained by the measuring light reflected from the patch structure 401. The light return collection structure 302 achieves self-focusing of the light through an integrated structure, ensuring the intensity of the reflected light signal to collect sufficient reflected light.

[0065] In some embodiments, the laser 1, fiber optic coupler 2, emission structure 3, pressure sensing element 4, N×N optical coupler 5, photodetector 6, and signal processing unit 7 are integrated on-chip. The blood pressure monitoring device of this disclosure, by integrating on-chip photonic platform, has a compact overall structure, which is beneficial for deployment in low-power, low-cost wearable embedded devices. It is suitable for high-reliability, artifact-free, continuous non-invasive blood pressure monitoring applications in dynamic environments.

[0066] In this embodiment, the N×N optical coupler 5 is a multi-port interference coupling structure, such as a 2×2 optical coupler, a 3×3 optical coupler, or a 4×4 optical coupler. This N×N optical coupler generates N interference light signals at the output port by interferometric superposition of the reference light and reflected light signals. , , ..., These N-way interferometric optical signals ( , , ..., There is a fixed relationship between them. The relative phase difference serves as the signal basis for subsequent phase demodulation and is used to construct the phase reconstruction model. Phase values ​​containing pulse vibration information can be decoupled using algebraic reconstruction or vector projection, thus retrieving the pulse vibration signal.

[0067] In some embodiments, the exit structure 3 includes a gradient refractive index lens or a convex lens group.

[0068] In some embodiments, the signal processing unit 7 is further configured to determine a pulse wave signal based on a vibration signal and to determine a blood pressure wave signal based on a transfer function and a pulse wave signal.

[0069] In this embodiment, the signal processing unit 7 integrates phase demodulation, pulse wave reproduction, and blood pressure wave mapping, realizing the final phase calculation, pulse wave reproduction, and blood pressure signal mapping reconstruction, which significantly improves the integration, reliability, and practicality of the blood pressure monitoring device.

[0070] In some embodiments, such as Figure 8 As shown, the blood pressure monitoring device also includes a frequency shifter, the two ends of which are connected to the fiber optic coupler and the N×N optical coupler, respectively, for shifting the frequency of the reference light.

[0071] To enable those skilled in the art to more clearly understand the technical solutions provided by the embodiments of this disclosure, the technical solutions provided by the embodiments of this disclosure will be described in detail below through specific embodiments: Figure 7 This is a blood pressure monitoring and measurement system according to an embodiment of the present disclosure. Figure 8 This is another blood pressure monitoring and measurement system in the embodiments of this disclosure.

[0072] Example 1 Reference Figure 7 This disclosure provides a zero-difference interferometric measurement system for blood pressure monitoring based on a 3×3 fiber optic coupler and a GRIN lens (GradientIndex Lens). The zero-difference interferometric measurement system of this embodiment includes a 1310nm laser diode, a 1×2 fiber optic coupler, a GRIN lens light return collection structure, a pressure detection element, a 3×3 optical coupler, a photodetector, and a signal processing module. The 3×3 optical coupler in this embodiment is a 3×3 MMI (Multi-Mode Interference) coupler. The specific working process is as follows: 1) A stable, continuous laser with a center wavelength of 1310nm is output from a 1310nm laser diode and input to a 1×2 fiber coupler; 2) A 1×2 fiber coupler splits a stable, continuous input laser with a center wavelength of 1310nm into a reference beam and a measurement beam; 3) The reference light enters the 3×3 MMI coupler from its input port; 4) The measuring light is self-focused through the GRIN Lens backlight collection structure. After being reflected by the pressure sensing element, it forms a reflected light signal, which enters the 3×3 MMI coupler from the input port. The pressure sensing element is a patch structure with high in-plane stiffness and low normal stiffness, which is used to convert the pressure of the pulse wave into the vibration of the patch structure. 5) The reference optical signal and the reflected optical signal interfere in a 3×3 MMI coupler to obtain the three-way phase difference. Interference light signal ( ); 6) The photodetector collects the phase difference of the three channels. Interference light signal ( ), and convert it into three electrical signals; 7) The signal processing module uses cosine fitting or algebraic reconstruction algorithm to perform phase demodulation, obtains interference phase, fits the vibration information obtained by demodulation to obtain pulse wave waveform, and maps and outputs blood pressure wave waveform according to pulse wave waveform.

[0073] Example 2 Reference Figure 7This disclosure provides a heterodyne interferometric measurement system for blood pressure monitoring based on a 4×4 optical coupler and lens group. The heterodyne interferometric measurement system of this embodiment includes a laser, a 1×2 fiber optic coupler, a convex lens light return collection structure, a pressure detection element, a 4×4 optical coupler, a photodetector, and a signal processing module. The 4×4 optical coupler in this embodiment is a 4×4 MMI (Multi-Mode Interference) coupler. The specific working process is as follows: 1) The laser output is stably and continuously input into a 1×2 fiber coupler; 2) A 1×2 fiber coupler splits the stable, continuous input laser into a reference beam and a measurement beam; 3) The reference light enters the 4×4 MMI coupler from its input port; 4) The measuring light is self-focused by the convex lens light return collection structure. After being reflected by the pressure detection element, it forms a reflected light signal, which enters the 4×4 MMI coupler from the input port. The pressure detection element is a patch structure with high in-plane stiffness and low normal stiffness, which is used to convert the pressure of the pulse wave into the vibration of the patch structure. 5) The reference optical signal and the reflected optical signal interfere in a 4×4 MMI coupler to obtain four-way phase differences. Interference light signal ( ); 6) The photodetector collects the phase difference of the four channels. Interference light signal ( ), and convert it into four electrical signals; 7) The signal processing module uses cosine fitting or algebraic reconstruction algorithm to perform phase demodulation, obtains interference phase, fits the vibration information obtained by demodulation to obtain pulse wave waveform, and maps and outputs blood pressure wave waveform according to pulse wave waveform.

[0074] The light-return collection structure of this embodiment employs a convex lens, making the overall structure of the system more flexible and allowing for improved measurement sensitivity through autonomous adjustment.

[0075] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. A method for monitoring blood pressure, comprising: Monitor the vibration signal perpendicular to the skin surface caused by the pulse wave of the subject; The pulse wave signal of the object under test is determined based on the vibration signal; The blood pressure wave signal of the subject to be tested is determined based on the transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

2. The blood pressure monitoring method according to claim 1, wherein, Monitoring vibration signals perpendicular to the skin surface caused by the pulse wave of the subject, including: The pressure of a pulse wave is detected by a pressure sensing element and converted into the vibration of the pressure sensing element. The pressure sensing element has high in-plane stiffness and low normal stiffness. The vibration of the pressure sensing element is monitored to determine the vibration signal.

3. The blood pressure monitoring method according to claim 2, wherein, Monitoring the vibration of the pressure sensing element and determining the vibration signal includes: The input laser beam is divided into a reference beam and a measurement beam; The pressure detection element is illuminated with the measuring light to obtain reflected light; The reference light and the reflected light are subjected to multimode interference to obtain multi-path interference light, wherein the multiple interference lights have a fixed phase difference. The vibration signal is determined based on the multiple interference beams.

4. The blood pressure monitoring method according to any one of claims 1 to 3, wherein, Based on the transfer function and the pulse wave signal, the blood pressure wave signal of the subject to be tested is determined, including: Acquire the calibrated pulse wave signal and calibrated blood pressure wave signal of the object under test; The transfer function of the test object is obtained by analyzing the calibrated pulse wave signal and the calibrated blood pressure wave signal. The blood pressure wave signal is obtained based on the transfer function and the pulse wave signal.

5. The blood pressure monitoring method according to claim 4, wherein, The calibrated pulse wave signal and the calibrated blood pressure wave signal are analyzed to obtain the transfer function of the test object, including: Morphological features are extracted from the calibrated pulse wave signal, wherein the morphological features include at least one of the following: the peak value of the main wave reflecting systolic pressure, the height and position of the tidal wave and dicrotic wave reflecting vascular tension and elasticity, the pulse cycle, the time of the main wave in the pulse cycle, the time of the tidal wave in the pulse cycle, and the time of the dicrotic wave in the pulse cycle. Determine the mapping relationship between the morphological features and blood pressure values; The transfer function is determined based on the calibrated pulse wave signal, the calibrated blood pressure wave signal, and the mapping relationship.

6. A blood pressure monitoring device, comprising: The vibration monitoring module is used to monitor vibration signals perpendicular to the skin surface caused by the pulse wave of the object under test; A pulse wave signal detection module is used to determine the pulse wave signal of the object under test based on the vibration signal. A blood pressure wave signal detection module is used to determine the blood pressure wave signal of the subject under test based on the transfer function and the pulse wave signal, wherein the transfer function characterizes the mapping relationship between the pulse wave signal and the blood pressure wave signal.

7. The blood pressure monitoring device according to claim 6, wherein, The vibration monitoring module includes: A pressure sensing element having high in-plane stiffness and low normal stiffness, used to convert the pressure of a pulse wave into vibration of the pressure sensing element; A vibration monitoring unit is used to monitor the vibration of the pressure detection element and determine the vibration signal.

8. The blood pressure monitoring device according to claim 7, wherein, The vibration monitoring unit includes: A laser, used to provide the input laser light; Fiber optic coupler for splitting the input laser into reference light and measurement light; An emission structure is used to illuminate the pressure sensing element with the measuring light and collect the reflected light from the pressure sensing element; An N×N optical coupler is used to interfere the input reference light and the reflected light to obtain multiple interference beams, wherein the multiple interference beams have a fixed phase difference, and N is an integer not less than 2; A photodetector is used to convert the multiple interference beams into electrical signals to obtain multiple electrical signals; A signal processing unit is used to generate the vibration signal based on the multiple electrical signals.

9. The blood pressure monitoring device according to claim 8, wherein, The exit structure includes a gradient refractive index lens or a convex lens group.

10. The blood pressure monitoring device according to claim 8, wherein, The blood pressure monitoring device also includes a frequency shifter, the two ends of which are connected to the fiber optic coupler and the N×N optical coupler, respectively, for shifting the reference light.

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