Integrated Biosensing System for Non-Contact Blood Flow Characterization
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Solution Overview
Problem
Current optical sensors for photoplethysmographic measurements face challenges in accurately characterizing blood flow without direct contact and in varying environmental conditions, such as different skin tones and ambient lighting, which affects signal quality and precision.
Innovation Solution
An integrated sensing system that includes a light source assembly and a light detector assembly integrated with an integrated circuit, capable of emitting and detecting multiple wavelengths of light, using a correlator to determine time delays and a sequencer to control frequencies, allowing for precise characterization of blood flow characteristics like pulse transit time and skin tone analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple wavelengths of light are used for photoplethysmographic measurements, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple light sources emitting different wavelengths (e.g., green and red light) with multiple photodetectors into a single integrated sensing system. This merging allows simultaneous multi-wavelength photoplethysmographic measurements to improve blood flow characterization precision while managing device complexity through integration.
Solution Approach 2:
The integrated sensing system is designed to perform multiple functions: it can measure blood flow characteristics using green light, switch to red light for different tissue penetration depths, and adapt to varying skin tones. This multi-functionality improves measurement precision across diverse conditions while the integrated design keeps the overall system complexity manageable.
2Ease of operation
If non-contact optical sensing is used for blood flow characterization, then ease of operation is improved, but measurement precision deteriorates due to environmental interference
Solution Approach 1:
The patent uses different wavelengths of light optimized for specific measurement conditions: green light (530nm) for superficial blood flow measurements and red light (660nm) for deeper tissue penetration. This local quality approach allows the system to maintain measurement precision in non-contact mode by selecting appropriate wavelengths for different environmental and tissue conditions.
Solution Approach 2:
The system changes operational parameters by switching between different light wavelengths and adjusting photodetector sensitivity based on environmental conditions and skin tone detection. This parameter adaptation maintains measurement precision while preserving the ease of non-contact operation.
3Measurement precision
If integrated circuit with correlator and sequencer is implemented, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent integrates the correlator and sequencer functions into a single integrated circuit together with the light sources and photodetectors. This merging improves measurement precision by providing precise time delay determination while managing manufacturing complexity through monolithic integration rather than discrete component assembly.
Solution Approach 2:
The patent replaces mechanical timing mechanisms with an integrated circuit-based correlator that uses electronic signal processing to determine time delays. This substitution improves measurement precision while simplifying manufacturing compared to mechanical timing systems.
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 and accurate non-contact blood flow characterization, including blood pressure, with a high signal-to-noise ratio, and adaptability to different skin tones and environments, making it suitable for compact applications like wearable technology.
Implementation Method 1
a light source assembly including a light source configured to emit light of a particular wavelength
Implementation Method 2
a light detector assembly including multiple light detectors configured to detect light of the particular wavelength
Data Source
AI summary
An integrated sensing system for characterizing blood flow in a subject includes a light source assembly including a light source configured to emit light of a particular wavelength. The integrated sensing system includes an integrated circuit electrically connected to the light source assembly. The integrated circuit includes a light detector assembly including multiple light detectors configured to detect light of the particular wavelength; and a correlator configured to determining a delay between optical signals detected by respective light detectors of the light detector assembly.