Fiber Grating Pulse Sensing for Continuous Cuffless Blood Pressure
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Solution Overview
Problem
Current non-invasive methods for measuring blood pressure and heart rate using fiber Bragg gratings are complex and expensive due to the need for wavelength detection instruments, and existing non-invasive methods like inflatable cuffs are not suitable for continuous monitoring.
Innovation Solution
A blood pressure and heart rate measuring device utilizing two fiber gratings to detect optical power and a protective structure for fiber gratings and optical paths, which includes a stretchable material and a tube to cover the gratings and optical paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavelength detection instruments are used to detect fiber Bragg grating wavelength changes for blood pressure and heart rate measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/optical wavelength detection system with an electrical detection system. Specifically, it uses a fiber grating whose reflection wavelength changes with vascular pulsation stress, coupled with a detection circuit that converts these wavelength changes into measurable electrical signals. This substitution eliminates the need for complex wavelength detection instruments while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that bridges the fiber grating's optical wavelength changes and the final electrical measurement. The fiber grating acts as a transducer that converts mechanical stress from vascular pulsation into optical wavelength shifts, which are then converted into electrical signals by the detection circuit. This intermediary approach simplifies the overall detection system.
2Ease of operation
If inflatable cuff method is used for non-invasive blood pressure measurement, then ease of operation is improved, but continuous monitoring capability deteriorates
Solution Approach 1:
The patent enables continuous monitoring by replacing the intermittent inflatable cuff method with a continuous fiber grating-based detection system. The fiber grating continuously tracks vascular pulsation stress in real-time, providing uninterrupted blood pressure and heart rate data without requiring periodic cuff inflation and deflation cycles.
Solution Approach 2:
The patent replaces the mechanical inflatable cuff system with an optical fiber-based sensing system. The fiber grating sensor can be integrated into wearable devices, allowing for comfortable, continuous, non-invasive monitoring without the mechanical complexity of inflation and deflation mechanisms.
3Measurement precision
If fiber Bragg grating sensors are used for pulse waveform measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive optical wavelength detection instruments with a cost-effective electrical detection circuit. The fiber grating itself remains the sensing element, but the detection methodology is changed from optical wavelength analysis to electrical signal measurement, dramatically reducing manufacturing costs while maintaining pulse waveform measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous, non-invasive, and cost-effective measurement of blood pressure and heart rate by detecting vascular pulsation through optical power, reducing complexity and cost associated with wavelength detection instruments.
Implementation Method 1
measure the waveform of vascular pulsation based on optical power... detecting changes in the reflection wavelength of the fiber Bragg grating... The first reflection wavelength band shifts with the vascular pulsating stress
Implementation Method 2
broadband light source... provide broadband light... connected to the broadband light source through a first optical path
Implementation Method 3
first photo receiver... configured to receive the fourth light ray from the second fiber grating through the fourth optical path and generate a first electrical signal of a pulse waveform of vascular pulsation in response to the fourth light ray
Data Source
AI summary
A blood pressure and heart rate measuring device has two fiber gratings for converting broadband light into a narrowband ray. The reflection wavelength band and the transmission wavelength band of one of the two fiber gratings will shift with the vascular pulsating stress of an object to be measured, which will change the optical power of the narrowband ray. Therefore, the pulse waveform obtained by the blood pressure and heart rate measuring device based on the optical power of the narrowband ray can be used to determine a blood pressure and a heart rate.