Blood Oxygen Sensor With Multi-Pass Light Path and Filtering
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Solution Overview
Problem
Conventional blood oxygen sensors face inaccuracies due to interference from other light sources and movement, limited light paths that miss substantial blood flow, and non-linear responses at lower light levels, leading to unreliable readings.
Innovation Solution
A blood oxygen sensing apparatus that uses an oscillating light with a specific frequency, directed through a light path that allows multiple passes through tissue, combined with a filtering system to attenuate secondary light sources and a light guiding apparatus to increase blood interaction, enabling accurate detection of oxygenated blood levels and circulatory characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensors use a limited light path through tissue, then the device structure is simple, but the light may miss substantial blood flow leading to inaccurate readings
Solution Approach 1:
The patent transitions from a single-pass linear light path to a multi-pass light path configuration. The light enters the tissue and undergoes multiple reflections and passes through the tissue repeatedly before exiting, effectively increasing the interaction length with blood vessels without proportionally increasing device size. This dimensional transformation of the light trajectory enables comprehensive blood flow detection while maintaining compact device structure.
2Measurement precision
If conventional sensors detect light directly without filtering, then the device complexity is low, but secondary light sources cause interference and inaccurate results
Solution Approach 1:
The patent extracts and removes the harmful secondary light components from the detected signal through filtering systems. The filter is specifically designed to block light from secondary sources (such as ambient light, LED indicators, or other interference) while allowing the primary measurement wavelength to pass through. This extraction of harmful elements enables accurate blood oxygen detection despite the presence of multiple light sources in the environment.
3Reliability
If the sensor uses oscillating light with filtering to reduce interference, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The patent employs periodic oscillation of the light source at a specific frequency (e.g., several hundred Hz to several kHz). The light modulator varies the light intensity periodically, and the detector is synchronized to detect only at this oscillation frequency. This periodic action creates a temporal signature that distinguishes the measurement signal from continuous or randomly varying interference sources, significantly improving reliability while using relatively simple electronic modulation and detection circuits.
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 solution effectively reduces interference from secondary light sources and movement, enhances blood interaction, and provides accurate measurements of blood oxygen levels and heart rate, improving the reliability of blood oxygen sensing.
Implementation Method 1
The oscillating light includes an electromagnetic wavelength which causes the oscillating light to be absorbed by some tissue of the person in amounts that are proportional to a volume of oxygenated blood in the tissue of the person
Implementation Method 2
The detector signal is filtered to attenuate at least a part of the second component of the detector signal and to pass the first component of the detector signal substantially un-attenuated
Data Source
AI summary
An exemplary embodiment providing one or more improvements includes a blood oxygen sensing apparatus and method in which an infra-red light is absorbed blood in portions that are related to levels of oxygen in the blood along a path.