Asymmetric Ring Sensor Layout for Accurate HR and SpO2 Sensing
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Solution Overview
Problem
Symmetrical sensor designs in wearable devices often result in inaccurate physiological data collection due to biological variations, particularly affecting heart rate and blood oxygen saturation measurements, and adding additional sensors for improved accuracy leads to bulkiness and increased power consumption.
Innovation Solution
Asymmetric sensor configurations with varying optical path lengths and penetration depths, utilizing a photodetector offset from the midpoint between light-emitting components, enable simultaneous accurate heart rate and blood oxygen saturation measurements without increasing device size or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If symmetrical sensor designs are used, then device structure is simple and manufacturing is easy, but measurement precision deteriorates due to biological variations affecting heart rate and blood oxygen saturation accuracy
Solution Approach 1:
The patent applies asymmetry by positioning the photodetector at an asymmetric location relative to the light-emitting components, specifically offset from the midpoint between them. This asymmetric arrangement creates different optical path lengths that enable simultaneous accurate measurement of both heart rate and blood oxygen saturation without requiring multiple sensor sets, thereby improving measurement precision while maintaining device simplicity
2Measurement precision
If additional sensors are added to improve measurement accuracy, then measurement precision improves, but device volume increases leading to bulkiness
Solution Approach 1:
The patent implements multi-functionality by designing a sensor configuration where the same set of light-emitting components and photodetector serve dual purposes: measuring both heart rate through one optical path and blood oxygen saturation through another optical path. This universal sensor system eliminates the need for separate sensor sets for different measurements, improving measurement precision while preventing device bulkiness
3Measurement precision
If additional sensors are added to improve measurement accuracy, then measurement precision improves, but power consumption increases
Solution Approach 1:
The patent achieves power efficiency through multi-functionality by having the same sensors perform multiple measurement tasks simultaneously. The light-emitting components and photodetector are configured to extract both heart rate and blood oxygen saturation information from the same optical signals, eliminating the need for additional sensors that would consume extra power, thus improving measurement precision without increasing power consumption
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 asymmetric sensor design enhances data accuracy by reducing noise and improving measurement precision for both heart rate and blood oxygen saturation, while maintaining a compact and energy-efficient wearable device.
Implementation Method 1
a first light-emitting component and a second light-emitting component
Implementation Method 2
a first photodetector located between the first light-emitting component and the second light-emitting component
Data Source
AI summary
Methods, systems, and devices for wearable device are described. A wearable device may include a first light-emitting component positioned within an inner circumferential surface of the wearable device at a first radial position and a second light-emitting component positioned within the inner circumferential surface of the wearable device at a second radial position, where the first radial position and the second radial position define a segment of the inner circumferential surface between the first radial position and the second radial position. Additionally, the wearable device may include a photodetector configured to receive light emitted by the first light-emitting component and the second light-emitting component. In some cases, the photodetector may be positioned at a third radial position within the segment of the inner circumferential surface between the first radial position and the second radial position, where the third radial position is offset from a radial midpoint of the segment.