Wear-State Adaptive SpO2 Sensing Under Motion and Light Noise
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Solution Overview
Problem
Wearable electronic devices experience inaccurate SpO2 measurements due to external light interference and user movement, especially in continuous measurement modes, leading to noise in PPG signals and reduced accuracy.
Innovation Solution
An electronic device with sensors and processors that identify its wearing state and adjust reference values for SpO2 calculations based on PPG signals, using threshold ranges to minimize movement-related noise and improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If continuous SpO2 measurement is performed using optical scheme, then SpO2 monitoring capability is improved, but measurement accuracy deteriorates due to external light interference and movement noise
Solution Approach 1:
The patent applies dynamics by making the reference value adaptive rather than static. The processor dynamically adjusts the reference value based on the detected wearing state (e.g., wrist position, movement level) to compensate for changing environmental conditions during continuous measurement, thereby maintaining accuracy despite movement and external light interference
Solution Approach 2:
The patent changes the parameter of reference value based on detected wearing state. By monitoring parameters such as acceleration data and contact force, the system adjusts the reference value parameter to match current wearing conditions, which compensates for noise introduced during movement and improves measurement accuracy in dynamic environments
2Ease of operation
If wearable electronic device is worn loosely for comfort, then ease of operation is improved, but measurement accuracy deteriorates due to increased external light infiltration
Solution Approach 1:
The system adjusts the reference value parameter based on the detected wearing state. When the device is worn loosely, the processor detects changes in contact force or acceleration patterns and modifies the reference value to compensate for increased external light interference, allowing comfortable wearing while maintaining measurement accuracy
Solution Approach 2:
The patent implements feedback by continuously monitoring wearing state parameters (acceleration, contact force) and using this information to adjust the reference value. This closed-loop approach allows the system to adapt to varying wearing conditions in real-time, compensating for loose fitting that increases external light infiltration
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
Enhances SpO2 measurement accuracy by adapting reference values to the device's wearing state, reducing noise from external light and movement, thereby improving the reliability of continuous SpO2 readings.
Implementation Method 1
The PPG signal is obtained by measuring a change in a change rate of absorption or penetration with respect to an internal light source, this may be implemented with the PPG sensor which uses a photodiode (PD)
Data Source
AI summary
An electronic device may include at least one sensor, a communication circuit, and at least one processor operatively connected with the at least one sensor and the communication circuit. The at least one processor may be configured to: if change amount of movement of the electronic device obtained via the at least one sensor is within a threshold range, identify a wearing state of the electronic device via the at least one sensor, select a group which corresponds to the wearing state from among a plurality of groups including a first group including saturations of percutaneous oxygen (SpO2s) which may correspond to reference values based on photoplethysmogram (PPG) signals and a second group including other SpO2s which may correspond to the reference values, and obtain a first PPG signal via the at least one sensor, and obtain a first SpO2 using the selected group and a first reference value which is based on the first PPG signal. Other embodiments are possible.