Optical Probe Pulse-Wave Measurement System
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Solution Overview
Problem
Existing vessel pulse wave measurement systems face challenges in obtaining accurate pulsation waveform data due to unstable operation caused by changes in attachment state, skin thickness, and type of optical probe, leading to inaccurate measurements and low accuracy in abnormal respiration detection.
Innovation Solution
A vessel pulse wave measurement system using an optical probe circuit with a light emitting element and a light receiving element, where the system includes a drive circuit, detection circuit, and a controller to control operating points for maximum self-oscillation signal levels, and a calibration part to convert blood pressure value voltage to blood pressure values, enabling accurate measurements across varying propagation distances and attachment conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light emitting element and light receiving element are used to measure pulse wave, then non-contact or non-invasive measurement is achieved, but measurement accuracy deteriorates due to unstable operation caused by changes in attachment state, skin thickness, and optical probe type
Solution Approach 1:
The system automatically adjusts the operating parameters (drive signal frequency, detection sensitivity) based on the measured propagation distance of light through the skin. By dynamically changing these parameters according to the specific attachment conditions and skin properties, the system maintains measurement accuracy across varying conditions while preserving the non-contact measurement advantage.
Solution Approach 2:
The system incorporates feedback mechanisms where the detected light signal characteristics are used to automatically adjust the drive circuit parameters and detection settings. This closed-loop control compensates for variations in attachment state and skin thickness, maintaining measurement precision without requiring manual recalibration or contact-based methods.
2Adaptability or versatility
If the propagation distance of light from the light emitting element to the light receiving element varies, then adaptability to different attachment conditions is improved, but measurement stability deteriorates
Solution Approach 1:
The system dynamically adapts its operating parameters based on the measured propagation distance. The drive circuit frequency and detection sensitivity are automatically adjusted according to the specific attachment conditions, allowing the system to maintain measurement stability across varying propagation distances while preserving adaptability to different attachment scenarios.
3Measurement precision
If a complex calibration system is used to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system performs self-calibration using the measured propagation distance and light signal characteristics. The calibration parameters are automatically determined based on the specific measurement conditions without requiring external calibration equipment or complex manual procedures. This self-service approach maintains measurement precision while minimizing device complexity.
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 achieves stable and accurate vessel pulse wave measurements and abnormal respiration detection with a simpler configuration, improving measurement accuracy and calibration efficiency compared to prior art.
Implementation Method 1
a light emitting element that radiates light to a blood vessel through skin and a light receiving element that receives, through the skin, reflected light from the blood vessel or transmitted light through the blood vessel
Implementation Method 2
a detection circuit that converts the light received by the light receiving element to an electrical signal and outputs the electrical signal
Data Source
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AI summary
A blood vessel pulse wave measurement system performs vessel pulse wave measurement using an optical probe circuit provided with an optical probe including a light emitting element and a light receiving element, a drive circuit, and a detection circuit. A measurement device directly and synchronously feeds back an electrical signal from the optical probe to the drive circuit as a drive signal to generate a self-oscillation signal from the detection circuit, and measures the self-oscillation signal as a vessel pulse wave signal. A controller controls an operating point of at least one of the detection circuit and the drive circuit such that the self-oscillation signal substantially reaches a maximum level thereof.