Multi-detector Optical Sensor for Finger Physiological Monitoring
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Solution Overview
Problem
Existing patient monitoring devices face challenges in accurately and reliably measuring physiological parameters due to variations in tissue geometry and scattering of photons, leading to potential measurement errors.
Innovation Solution
The development of a noninvasive physiological sensor with multiple detectors and/or multiple emitters, arranged to obtain measurements related to different path lengths or tissue geometries, improving accuracy and reliability by reducing total measurement error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single detector is used to measure physiological parameters, then the device complexity is low, but the measurement precision deteriorates due to variations in tissue geometry and photon scattering
Solution Approach 1:
The sensor divides the detection function into multiple detectors (e.g., first detector, second detector, third detector) positioned at different locations. Each detector measures light attenuation along different path lengths through the tissue, allowing the system to segment the measurement process to account for varying tissue geometries and scattering patterns, thereby improving measurement precision
Solution Approach 2:
The patent introduces spatial dimensionality by positioning detectors at different locations (e.g., opposite sides, offset positions) around the tissue site. This multi-dimensional arrangement allows measurement of light attenuation along multiple path lengths and angles, transforming a single-point measurement into a multi-point spatial measurement that compensates for tissue geometry variations
2Reliability
If multiple detectors are used to account for different path lengths, then the reliability of physiological parameter determination improves, but the device complexity increases
Solution Approach 1:
The sensor system segments the measurement function across multiple detectors, where each detector is responsible for measuring light attenuation along a specific path length. This segmentation allows the system to obtain multiple independent measurements that can be combined to improve reliability and reduce the impact of errors from any single detector
Solution Approach 2:
The patent changes the measurement parameters by using detectors with different path lengths (e.g., short path length, long path length). This parameter variation allows the system to measure both superficial and deep tissue characteristics, improving the reliability of physiological parameter determination by providing a more comprehensive view of tissue optics
3Reliability
If detectors are positioned at different locations to measure different tissue geometries, then the robustness of measurement against scattering errors improves, but the ease of operation deteriorates due to alignment requirements
Solution Approach 1:
The sensor design incorporates multiple detectors that can function independently or in combination, allowing the same sensor to perform multiple measurement functions (e.g., transmissive mode, reflectance mode) with different path lengths. This multi-functionality improves robustness against scattering errors while maintaining ease of operation through a unified sensor design
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
This configuration enhances the accuracy, reliability, and robustness of physiological parameter determinations by accounting for varying tissue geometries and scattering patterns, thereby reducing measurement errors.
Implementation Method 1
One or more photo detection devices detect the light after interaction with tissue of the portion of the body
Implementation Method 2
variations in tissue geometry and scattering of photons, leading to potential measurement errors
Data Source
AI summary
Various noninvasive physiological sensors are described herein. Some implementations of the sensors described herein include multiple emitters and/or detectors positioned at various portions of a measurement site and configured to operate in either or both of transmittance and reflectance modes. In one implementation, a noninvasive physiological sensor includes a body portion configured to secure to a finger of a subject, an emitter operably positioned by the body portion at a first side of the finger and configured to emit light of one or more wavelengths into tissue of the finger, a first detector operably positioned by the body portion at a second side of the finger opposite the first side, and a second detector operably positioned by the body portion at a third side of the finger and offset approximately 90 degrees from the emitter with respect to an axis extending through at least a portion of the body portion.