Multi-Emitter PPG Sensor Array for Directional Blood Flow Monitoring
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Solution Overview
Problem
Current photoplethysmography (PPG) sensors lack the capability to effectively monitor directional blood flow and velocity, relying on single signal streams which are prone to noise and limited in accuracy for physiological parameter monitoring.
Innovation Solution
The development of multi-emitter and multi-detector sensor arrays that generate multiple PPG signal streams from a single body site, allowing for the analysis of phase differences to determine blood flow direction and velocity, along with other parameters like blood pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single signal stream PPG sensors are used, then device complexity is reduced, but measurement precision of directional blood flow and velocity deteriorates
Solution Approach 1:
The sensor is divided into multiple emitter-detector pairs arranged in specific geometric configurations. Each pair generates an independent PPG signal stream, allowing the system to segment the measurement process into multiple directional components that can be processed separately to determine blood flow direction and velocity.
Solution Approach 2:
The patent transitions from single-dimensional (single signal stream) to multi-dimensional (multiple signal streams with spatial relationships) measurements. By arranging emitters and detectors in three-dimensional configurations and analyzing phase differences across multiple signal streams, the system adds spatial dimensionality to the measurement, enabling directional blood flow and velocity monitoring.
2Measurement precision
If multiple PPG signal streams are generated from a single body site, then measurement precision of physiological parameters is improved, but device complexity increases
Solution Approach 1:
The multi-emitter and multi-detector sensor array is designed to perform multiple functions simultaneously: monitoring blood oxygen saturation, perfusion, respiration, blood volume, magnitude of blood flow, directional blood flow, and velocity. This universal approach allows a single complex sensor to replace multiple specialized sensors, improving measurement precision across various physiological parameters while consolidating the device structure.
3Measurement precision
If phase difference analysis is used to determine blood flow direction and velocity, then measurement precision is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The system implements feedback mechanisms where the phase differences between multiple PPG signal streams are continuously analyzed and processed. The signal processing algorithms use feedback from the relative phase relationships to iteratively determine blood flow direction and velocity, improving measurement precision through continuous refinement of the measurements based on phase correlation analysis.
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 precise monitoring of directional blood flow and velocity, improving the accuracy of physiological parameter measurement, including blood pressure, by utilizing multiple PPG signal streams and advanced signal processing techniques.
Implementation Method 1
Photoplethysmography, or 'PPG', is an optical technique for detecting blood volume changes in a tissue. In this technique, one or more emitters are used to direct light at a tissue and one or more detectors are used to detect the light that is transmitted through the tissue
Implementation Method 2
The volume of blood, or perfusion, of the tissue affects the amount of light that is transmitted or reflected
Data Source
AI summary
Provided according to embodiments of the invention are methods of monitoring the direction of blood flow that include processing with a computer photoplethysmography (PPG) signal streams from a sensor array on a body site of the individual to determine the direction and/or velocity of the blood flow at the body site of the individual. In some embodiments, direction of the blood flow at the body site is determined by the phase difference between at least three PPG signal streams from the sensor array, wherein the at least three PPG signal streams are generated from emissions of the at least three emitters.