Rotatable Finger Sensor for Shortening Optical Path
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Solution Overview
Problem
Current noninvasive physiological monitoring devices face challenges in accurately measuring physiological parameters due to the need for longer optical radiation transmission paths, which can lead to reduced accuracy and user discomfort, especially when trying to penetrate through bone tissue.
Innovation Solution
A noninvasive physiological sensor design featuring a rotatable mechanism that compresses tissue to shorten the optical radiation transmission path, using aligned optical fibers to direct and detect light, allowing for more precise measurement of parameters like oxygen saturation and pulse rate without passing through bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If the optical radiation transmission path is lengthened to penetrate through bone tissue, then the ability to detect signals from deeper tissue layers is improved, but measurement accuracy deteriorates and user discomfort increases
Solution Approach 1:
The patent applies parameter changes by adjusting the optical path length to a specific range (0.2-1.0 cm) that optimizes the balance between penetrating deep enough to detect blood flow signals and maintaining sufficient signal strength for accurate measurement. This resolves the contradiction by finding the optimal parameter value rather than simply maximizing path length.
Solution Approach 2:
The sensor employs a dynamic compression mechanism that adjusts the tissue compression force to optimize the optical path. The compression is controlled to be sufficient to shorten the path through bone but not so much as to cause discomfort or distort physiological parameters, dynamically balancing detection depth and measurement accuracy.
2Difficulty of detecting and measuring
If the optical radiation transmission path is lengthened to penetrate through bone tissue, then the ability to detect signals from deeper tissue layers is improved, but user comfort deteriorates
Solution Approach 1:
The patent changes the compression parameter to an optimal range that provides sufficient tissue shortening for deep signal detection while remaining below the threshold of user discomfort. This resolves the contradiction by identifying and implementing the optimal parameter value.
Solution Approach 2:
The dynamic compression mechanism adjusts the force applied to the tissue, providing just enough compression to achieve the desired optical path length for deep tissue detection without exceeding comfort thresholds, thereby resolving the contradiction between detection capability and user comfort.
3Measurement precision
If tissue compression is applied to shorten the optical radiation transmission path, then measurement accuracy is improved, but the complexity of the device increases
Solution Approach 1:
The patent implements a dynamic compression mechanism that automatically adjusts tissue compression to optimize the optical path length. This dynamic approach improves measurement accuracy by maintaining optimal compression conditions while managing device complexity through automated control rather than manual adjustment.
Solution Approach 2:
The compression force is controlled within specific parameter ranges to achieve the desired optical path length. By defining and controlling compression parameters within optimal bounds, the patent improves measurement accuracy while managing device complexity through parameter specification rather than complex mechanical 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
This design enhances measurement accuracy by focusing on a shorter tissue path, reducing user discomfort, and improving the ability to detect signals from deeper tissue layers, thereby providing higher quality physiological data.
Implementation Method 1
one or more light sources that transmit optical radiation into a portion of the body... After attenuation by tissue and fluids of the portion of the body, one or more photodetection devices detect the attenuated light
Implementation Method 2
a rotatable mechanism that compresses tissue to shorten the optical radiation transmission path
Data Source
AI summary
A noninvasive physiological sensor can include a first body portion and a second body portion coupled to each other and configured to at least partially enclose a user's finger. The sensor can further include a first probe coupled to one or more emitters and a second probe coupled to a detector. The first probe can direct light emitted from the one or more emitters toward tissue of the user's finger and the second probe can direct light attenuated through the tissue to the detector. The first and second probes can be coupled to the first and second body portions such that when the first and second body portions are rotated with respect to one another, ends of the first and second probes can be moved in a direction towards one another to compress the tissue of the user's finger.