LED Array Sensor for Heart Rate and Blood Oxygen Detection
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Solution Overview
Problem
Existing sensors for detecting heart rate and blood oxygen content often have limitations in measurement accuracy due to the distance between radiation sources and the complexity of signal separation.
Innovation Solution
A sensor with a light-emitting diode array comprising first and second light-emitting diodes of different wavelengths, where the distance between them is 100 micrometers or less, and a controller to operate them independently with variable voltage and frequency, allowing for improved signal separation and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between light-emitting diodes of different wavelengths is increased to reduce mutual interference, then signal separation becomes easier, but measurement accuracy deteriorates because light penetrates differently into tissue at different distances
Solution Approach 1:
The patent merges the detection of heart rate and blood oxygen content into a single integrated sensor unit with light-emitting diodes positioned at minimal distance (100 micrometers or less). This combining approach allows simultaneous measurement of both parameters without requiring separate sensor placements, thereby improving measurement accuracy while maintaining manageable device complexity through unified signal processing
Solution Approach 2:
The patent employs periodic modulation of light-emitting diodes at different frequencies to enable temporal separation of signals. By oscillating the first and second light-emitting diodes at distinct periodic frequencies and processing the photodetector output accordingly, the system achieves effective signal separation despite the minimal spatial distance between diodes, thus resolving the contradiction between measurement accuracy and signal separation complexity
2Measurement precision
If multiple light-emitting diodes are placed close together to improve tissue penetration consistency, then measurement accuracy improves, but the complexity of independent operation and signal separation increases
Solution Approach 1:
The patent applies periodic modulation at different frequencies to each light-emitting diode, allowing independent operation control through frequency discrimination. The controller modulates the first light-emitting diode at a first frequency and the second light-emitting diode at a second frequency, enabling easy independent operation while maintaining close physical proximity for consistent tissue penetration
Solution Approach 2:
The patent implements feedback-based signal processing where the photodetector output is analyzed to separately identify signals from each light-emitting diode based on their distinct modulation frequencies. This feedback mechanism simplifies the operation of multiple closely-placed diodes by automatically separating their contributions through frequency-dependent signal processing
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 measurement accuracy by ensuring that light from both wavelengths penetrates similarly into tissue, improving heart rate and blood oxygen content detection.
Implementation Method 1
the radiation source includes a light-emitting diode array, the light-emitting diode array includes a plurality of emission regions, the emission regions each include a first light-emitting diode and a second light-emitting diode, the first light-emitting diode includes a first wavelength, the second light-emitting diode includes a second wavelength
Implementation Method 2
a sensor that detects a heart rate and/or a blood oxygen content, including a radiation source and a photodetector
Data Source
AI summary
A sensor that detects a heart rate and/or a blood oxygen content includes a radiation source and a photodetector, wherein the radiation source includes a light-emitting diode array, the light-emitting diode array includes a plurality of emission regions, the emission regions each include a first light-emitting diode and a second light-emitting diode, the first light-emitting diode includes a first wavelength, the second light-emitting diode includes a second wavelength, and a distance between the first light-emitting diode and the second light-emitting diode within the emission regions is 100 micrometers or less.