Multi-Depth PPG Sensor Layout for Accurate Wrist Oximetry
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Solution Overview
Problem
The accuracy of health detection data is relatively low due to the complex tissue structure of the wrist, which interferes with the detection of blood oxygen and heart rate when using wearable devices.
Innovation Solution
A detection apparatus with a specific arrangement of first and second light sources and photodetectors, forming multiple light paths and PPG modules to enhance data accuracy by increasing the number of skin depths sampled, and reducing interference from complex tissue structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a finger-clip oximeter is used to detect blood oxygen on the fingertip, then detection accuracy is improved, but the fingertip cannot move normally and has a squeezing sensation
Solution Approach 1:
The detection apparatus segments the detection function by using multiple independent light sources and photodetectors arranged in different spatial positions, forming multiple light paths that can detect different tissue depths independently, thereby improving detection accuracy without requiring strong clamping force
Solution Approach 2:
The patent transitions from single-point detection to multi-dimensional detection by arranging light sources and photodetectors in spatial configurations that create multiple light paths penetrating different tissue depths, enabling detection at multiple dimensional levels simultaneously
2Ease of operation
If a wearable device is used to perform blood oxygen detection on the wrist, then ease of operation is improved, but detection accuracy is reduced due to complex tissue structure
Solution Approach 1:
The detection apparatus divides the detection task into multiple independent light paths with different penetration depths, allowing the system to selectively use signals from shallower depths that are less affected by the complex wrist tissue structure, thereby maintaining accuracy in a comfortable wearable configuration
Solution Approach 2:
The patent changes the detection parameters by using multiple light wavelengths and multiple detection depths, enabling the system to identify and prioritize signals from tissue layers that provide accurate blood oxygen measurements while filtering out interference from the complex wrist tissue structure
3Measurement precision
If multiple light sources and photodetectors are arranged to form multiple light paths, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The detection apparatus uses multiple light sources and photodetectors that serve multiple functions simultaneously - each component participates in multiple light paths and can detect multiple physiological parameters, thereby achieving high detection accuracy without proportionally increasing device complexity
Solution Approach 2:
The patent merges the functions of multiple light sources and photodetectors into a unified detection system where components work together in coordinated light paths, sharing common signal processing and control circuits, which reduces overall system complexity while maintaining multiple detection capabilities
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 apparatus improves detection accuracy by increasing the number of light paths and PPG modules, allowing for more precise analysis of blood oxygen and heart rate data by comparing and analyzing PPG data from different light paths and depths, thereby enhancing the signal-to-noise ratio.
Implementation Method 1
the first light sources and the first photodetectors may be referred to as outer-ring light sources... one light path may be formed between one first light source and one first photodetector, so that the first light source and the first photodetector in the light path may form one PPG module
Implementation Method 2
a distance between a light source and a photodetector may determine an effective depth that is in the skin and at which light emitted by the light source arrives
Implementation Method 3
the detection apparatus can obtain PPG data of at least four skin depths... based on detection results of the detection apparatus, an electronic device may not only compare and analyze PPG data obtained from different light paths
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~4
AI summary
Embodiments of this application relate to the field of health data detection technologies, and provide a detection apparatus and an electronic device, to resolve a problem that accuracy of health detection data is relatively low due to a complex tissue structure of a to-be-monitored part of a user. In the detection apparatus, a first photodetector is disposed between two adjacent first light sources, and second light sources are located in a detection region enclosed by a plurality of first light sources and a plurality of first photodetectors. The first light source has a first distance H1 and a second distance H2 from at least two of all first photodetectors, and the second light source has a third distance H3 and a fourth distance H4 from at least two of all first photodetectors. The first light sources, the second light sources, and the first photodetectors are distributed in distribution regions of the detection apparatus. Each light source and one photodetector may form one PPG module, and an effective detection depth in skin may vary with a distance between the light source and the photodetector.