Optical Waveguide Motion Sensor for Non-Invasive Blood Pressure
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Solution Overview
Problem
Current non-invasive blood pressure measurement methods, such as auscultatory and oscillometric methods, are limited in accuracy and require calibration, and do not effectively detect arterial pulses at pressures above systolic pressure, making them less reliable for continuous monitoring and precise vital sign measurements.
Innovation Solution
An optical motion sensing system using optical power modulation with a deformable optical waveguide, where the displacement of a sensor pad causes flexing or compression of the waveguide, reducing optical energy transmission, allowing for accurate detection of arterial pulses and vital sign measurements by monitoring the amount of light exiting the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional auscultatory or oscillometric methods are used for blood pressure measurement, then the measurement can be performed non-invasively, but the accuracy is limited and calibration is required
Solution Approach 1:
The patent replaces conventional mechanical pressure sensing methods with an optical sensing system. An optical waveguide is placed against the skin to detect arterial pulse movements through optical power modulation, eliminating the need for mechanical pressure transducers and calibration procedures while improving measurement accuracy.
Solution Approach 2:
The optical sensing system automatically detects arterial pulse characteristics without requiring external calibration or manual adjustment. The system self-calibrates by directly measuring optical changes caused by arterial expansion and contraction, providing immediate accurate readings without prior calibration steps.
2Adaptability or versatility
If conventional methods are used, then the device structure is simple, but the ability to detect arterial pulses at pressures above systolic pressure is insufficient
Solution Approach 1:
The patent changes the detection parameter from direct mechanical pressure measurement to optical power modulation. By measuring changes in light transmission through the waveguide caused by arterial pulse movements, the system can detect pulses across a wider pressure range including above-systolic pressures that conventional pressure sensors cannot accurately measure.
3Measurement precision
If optical waveguide compression is used to detect motion, then measurement precision is improved, but optical energy transmission is reduced
Solution Approach 1:
The patent converts the harmful effect of optical energy loss into a beneficial measurement signal. The compression of the waveguide, which normally would reduce light transmission, is instead utilized as the detection mechanism itself. The degree of compression is measured by monitoring the resulting optical power changes, transforming the energy loss into useful displacement information.
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
The system enables precise determination of systolic and diastolic blood pressure, heart rate, and other vital signs without the need for calibration, and can detect arterial pulses at pressures below systolic, improving accuracy and reliability in continuous monitoring.
Implementation Method 1
an optical waveguide, an optical source device, and an optical detector. The optical waveguide is positioned within the sensor frame such that the movement of the sensor pad results in the flexing or compressing of the optical waveguide
Implementation Method 2
The optical detector detects an amount of optical energy exiting the optical waveguide
Data Source
AI summary
An optical motion sensing device included a sensor frame defining an opening, a sensor pad disposed in the opening, an optical sensing system adapted to detect an amount of movement of the sensor pad in the sensor frame, and an output unit. The optical sensing system includes an optical waveguide, an optical source device, and an optical detector. The optical waveguide is positioned within the sensor frame such that the movement of the sensor pad results in the flexing or compressing of the optical waveguide. The optical source device supplies optical energy to the optical waveguide. The optical detector detects an amount of optical energy exiting the optical waveguide. The output unit is configured to receive a signal indicative of the amount of optical energy exiting the optical waveguide and to generate a measure of the amount of movement of the sensor pad from the received signal.