Search

EP-4458259-B1 - BLOOD PRESSURE MEASUREMENT METHOD FOR WEARABLE DEVICE AND WEARABLE DEVICE

EP4458259B1EP 4458259 B1EP4458259 B1EP 4458259B1EP-4458259-B1

Inventors

  • SU, DAN
  • LIU, YI
  • CHONG, Hao

Dates

Publication Date
20260506
Application Date
20230410

Claims (15)

  1. A blood pressure measurement method of a wearable device (100, 1700), wherein the wearable device (100, 1700) comprises a pressure transducer (120), PT, a display screen (161), and a photo diode, PD, (131); and the method comprises: emitting an optical signal through a first region of the display screen (161); converting, into a first PPG signal, the optical signal received by the PD (131), wherein the optical signal emitted by the first region is absorbed and scattered by skin tissue to form a reflected signal, and the PD converts the reflected signal into the first PPG signal; determining whether the first PPG signal satisfies a signal quality requirement by calculating a perfusion rate of the first PPG signal and comparing the perfusion rate to a preset perfusion rate or by calculating an intensity of the first PPG signal and comparing the intensity to a preset intensity; if the first PPG signal satisfies the signal quality requirement: obtaining a pressure value collected by the PT (120); and determining a blood pressure value of a wearer based on the pressure value and the first PPG signal; if the first PPG signal does not satisfy a signal quality requirement: emitting the optical signal through a second region of the display screen (161), wherein the second region and the first region are different in at least one of the following features: a position, a luminance, an area size, or a shape on the display screen (161); converting, into a second PPG signal, the optical signal received by the PD (131); determining whether the second PPG signal satisfies the signal quality requirement by calculating a perfusion rate of the second PPG signal and comparing the perfusion rate to the preset perfusion rate or by calculating an intensity of the second PPG signal and comparing the intensity to a preset intensity; if the second PPG signal satisfies the signal quality requirement: obtaining a pressure value collected by the PT (120) when the second PPG signal satisfies the signal quality requirement; and determining a blood pressure value of a wearer based on the pressure value and the second PPG signal.
  2. The method according to claim 1, wherein, if the first PPG signal does not satisfy a signal quality requirement comprises: a perfusion rate of the first PPG signal is less than or equal to a preset perfusion rate, a distance between a projection region of the PD (131) on the display screen (161) and the second region is greater than a distance between the projection region of the PD (131) on the display screen (161) and the first region.
  3. The method according to claim 1, wherein, if the first PPG signal does not satisfy a signal quality requirement comprises: an intensity of the first PPG signal is less than or equal to a preset intensity, the luminance of the second region is greater than the luminance of the first region.
  4. The method according to claim 3, wherein the luminance of the second region is a maximum value; and the method further comprises: emitting the optical signal through a third region of the display screen (161) if the second PPG signal does not satisfy the signal quality requirement, wherein a distance between a projection region of the PD (131) on the display screen (161) and the third region is less than a distance between the projection region of the PD (131) on the display screen (161) and the first region; converting, into a third PPG signal, the optical signal received by the PD (131); obtaining the pressure value collected by the PT (120) when the third PPG signal satisfies the signal quality requirement; and determining the blood pressure value of the wearer based on the pressure value and the third PPG signal.
  5. The method according to claim 1, wherein the shape of the second region is different from the shape of the first region; or the area size of the second region is different from the area size of the first region.
  6. The method according to any one of claims 1 to 5, wherein the pressure value comprises a plurality of pressure values, the second PPG signal comprises a plurality of second PPG signals, the plurality of pressure values are in a one-to-one correspondence with the plurality of second PPG signals, and a collection moment of each of the plurality of pressure values is same as that of a corresponding one of the second PPG signals; and the determining a blood pressure value of a wearer based on the pressure value and the second PPG signal comprises: extracting a waveform feature of each of the plurality of second PPG signals; and determining, if a target second PPG signal whose waveform feature is less than or equal to a preset waveform feature exists in the plurality of second PPG signals, a pressure value corresponding to the target second PPG signal as a systolic blood pressure, SBP, in the blood pressure value of the wearer.
  7. The method according to any one of claims 1 to 6, wherein the pressure value comprises a plurality of pressure values, the second PPG signal comprises a plurality of second PPG signals, the plurality of pressure values are in a one-to-one correspondence with the plurality of second PPG signals, and a collection moment of each of the plurality of pressure values is same as that of a corresponding one of the second PPG signals; and the determining a blood pressure value of a wearer based on the pressure value and the second PPG signal comprises: extracting a waveform feature of each of the plurality of second PPG signals; and inputting the plurality of pressure values and the waveform features of the plurality of second PPG signals into a neural network model, wherein the neural network model is trained based on a historical pressure value and a waveform feature of a historical PPG signal, and is configured to measure blood pressure; and determining output of the neural network model as a diastolic blood pressure DBP in the blood pressure value of the wearer.
  8. The method according to any one of claims 1 to 7, wherein before the obtaining a pressure value collected by the PT (120), the method further comprises: outputting an operation guide, wherein the operation guide is configured to guide the wearer to apply a pressure perpendicular to a contact surface between the wearable device (100, 1700) and human skin to the wearable device (100, 1700) in a preset pressing region, and the operation guide comprises a pressure value required for the wearer to press.
  9. The method according to claim 8, further comprising: ending, during the pressure application by the wearer, blood pressure measurement if the following condition is satisfied: an acceleration of the wearable device (100, 1700) is greater than an acceleration threshold; and/or an angular velocity of the wearable device (100, 1700) is greater than an angular velocity threshold.
  10. The method according to claim 8 or 9, further comprising: displaying a first interface, wherein the first interface is configured to display a pressure curve, prompt information, and a waveform of the second PPG signal, the pressure curve is the operation guide, and the prompt information is configured for prompting a pressing duration of the wearer.
  11. The method according to any one of claims 1 to 10, wherein before the emitting an optical signal through a first region of the display screen (161), the method further comprises: determining whether the wearable device (100, 1700) satisfies a blood pressure measurement condition; and the emitting an optical signal through a first region of the display screen (161) comprises: emitting the optical signal through the first region of the display screen (161) when the blood pressure measurement condition is satisfied.
  12. The method according to claim 11, wherein the blood pressure measurement condition comprises at least one of the following: the acceleration of the wearable device (100, 1700) is less than or equal to the acceleration threshold, the pressure value is greater than or equal to a pressure threshold, or the angular velocity of the wearable device (100, 1700) is less than or equal to the angular velocity threshold, wherein the acceleration is configured for representing a contact situation between the wearable device (100, 1700) and the wearer, and the pressure value is configured for representing a tightness for wearing the wearable device (100, 1700).
  13. The method according to any one of claims 1 to 12, wherein the display screen (161) is supported by a screen bracket, the screen bracket comprises an optical window, the PD (131) is directly below the optical window, a preset distance is defined between the PD (131) and the optical window, the PT (120) is located at a bottom of the wearable device (100, 1700) and is configured to collect a pressure value between the wearable device (100, 1700) and a wearing part, and the wearing part is a contact part between the wearable device (100, 1700) and the wearer.
  14. A wearable device (100, 1700), comprising: a processor (1710), wherein the processor (1710) is coupled to a memory (1730), the memory (1730) is configured to store a computer program, and when the processor (1710) invokes the computer program, the wearable device (100, 1700) is caused to perform the method according to any one of claims 1 to 13.
  15. A computer-readable storage medium, configured to store a computer program, wherein the computer program comprises an instruction for implementing the method according to any one of claims 1 to 13.

Description

This application claims priority to Chinese Patent Application No. 202210875921.7, filed with the China National Intellectual Property Administration on July 25, 2022 and entitled "BLOOD PRESSURE MEASUREMENT METHOD OF WEARABLE DEVICE, AND WEARABLE DEVICE". TECHNICAL FIELD This application relates to the field of terminal technologies, and in particular, to a blood pressure measurement method of a wearable device, and a wearable device. BACKGROUND With the development of wearable devices, the wearable device may support increasingly more functions. To satisfy needs of users for health management thereof, a relatively large quantity of wearable devices may support a human body data monitoring function of the user. For example, a smartwatch may measure a human body feature such as a heart rate, a respiration rate, blood pressure, or blood oxygen. Currently, for measurement of the blood pressure, a method for obtaining a blood pressure value based on a photoplethysmography (photoplethysmography, PPG) signal of a fingertip and a fingertip pressure exists on the market. The user applies a pressure to the wearable device through the fingertip, and the wearable device obtains the pressure of the fingertip through a pressure transducer (pressure transducer, PT), and emits an optical signal through a light emitting diode (light emitting diode, LED) in a PPG module. The optical signal is absorbed and scattered by skin tissue of the fingertip to form a reflected signal. The reflected signal may be received by a photo diode (photo diode, PD) in the PPG module and converted into a PPG signal. The wearable device may obtain the blood pressure value based on a waveform of the PPG signal of the fingertip. However, the method has a problem that the blood pressure value obtained through measurement is inaccurate. US 2019/008399 A1 describes a system and method for cuff-less blood pressure measurement in a mobile device. A key aspect of this disclosure is the discovery of a new location for blood pressure measurement at the fingertip of a subject and that reflectance-mode photoplethysmography can be used to help make this measurement. Through experiments in human subjects, it was discovered that it is indeed possible to measure systemic blood pressure by having a subject press the fingertip against a reflectance-mode photo-plethysmography-force sensor unit under visual guidance and then compute blood pressure from the resulting variable-amplitude blood volume oscillations and applied pressure via an oscillometric algorithm. US 2020/093377 A1 describes an apparatus for estimating bio-information. The apparatus for estimating bio-information includes: a sensor part comprising a pulse wave sensor array configured to detect a pulse wave signal when an object contacts a contact surface of the sensor part, and a load sensor configured to detect a first contact load applied by the object to the contact surface; and a processor configured to obtain contact load distribution of the contact surface based on the pulse wave signal, and to estimate bio-information based on the contact load distribution. US 2020/113442 A1 describes blood pressure detection apparatuses and methods for detecting a blood pressure of a user comprising optical sensors/detectors and a force sensor and, in some embodiments, comprising only a force sensor, measuring force applied by a finger. Blood pressure is measured by applying an increasing (or decreasing) force or pressure with a finger of the user on at least the force sensor, which, in some embodiments, may be a plurality of increasing pressure steps, each step being held within a predetermined acceptable pressure/force tolerance range for a predetermined hold time, and measuring the force applied by the finger and, in some embodiments, optically measuring the blood in a vessel in the finger relating to the applied pressure/force. Feedback (visual, haptic, sound) of the applied pressure is provided to the user. CN 110 141 197 A describes electric equipment with a display screen. The electric equipment with the display screen is used for obtaining physiological characteristics and/or pathological characteristicsby acquiring the biometric information of a user. The electric equipment with the display screen comprises a PPG light receiving unit and a PPG obtaining unit, wherein the PPG light receiving unit isused for receiving a light signal and converting the light signal into a pulse wave signal; the PPG obtaining unit is used for receiving and processing the pulse wave signal from the PPG light receiving unit to obtain physiological characteristics and/or pathological characteristics; the display screen is arranged in a manner that the reflected part of the light emitted by the display screen to the first side can penetrate through the display screen to reach the second side opposite to the first side, and the reflected part of the light is received by the PPG light receiving unit arranged on the second side