Optical Sensor Device with Variable Emitter-Detector Spacing
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Solution Overview
Problem
Existing sensor devices for health and fitness monitoring face challenges in accurately measuring heart rate and arterial oxygen saturation due to limitations in light absorption and reflection measurements through the skin, particularly in distinguishing between different spectral ranges.
Innovation Solution
A sensor device with a configuration of multiple light emitters and detectors, where the distance between emitters and detectors varies to account for wavelength-dependent light absorption and reflection, using filters to ensure accurate detection within specific spectral ranges, allowing for precise measurement of heart rate and oxygen saturation without invasive methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light emitters with different spectral ranges are used, then measurement accuracy for multiple parameters is improved, but device complexity increases
Solution Approach 1:
The sensor device is segmented into multiple independent measurement channels, each with dedicated light emitters and detectors for specific spectral ranges. This allows simultaneous measurement of multiple parameters (heart rate, oxygen saturation) with optimized wavelength selection for each parameter, improving overall measurement accuracy while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The sensor device achieves multi-functionality by integrating multiple light emitters covering different spectral ranges (visible and infrared) and multiple detectors that can process signals from various wavelengths. This universal design enables the single device to measure multiple physiological parameters simultaneously, improving measurement accuracy without requiring separate dedicated devices for each parameter
2Measurement precision
If distance between light emitter and detector is increased, then light absorption and reflection measurements are improved, but signal intensity detected decreases
Solution Approach 1:
Different distance configurations are applied locally to different measurement channels based on their specific requirements. The first distance configuration optimizes for absorption measurements while the second distance configuration optimizes for reflection measurements. This localized optimization allows each measurement type to achieve maximum accuracy while compensating for signal intensity variations through the use of multiple detectors with appropriate sensitivity characteristics
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 configuration enhances measurement accuracy and reliability by optimizing the distance and arrangement of light emitters and detectors, enabling precise optical measurement of heart rate and oxygen saturation with reduced susceptibility to errors and compact device design.
Implementation Method 1
measuring light absorption when shining through the skin of the user
Implementation Method 2
measuring light absorption when shining through the skin of the user
Data Source
AI summary
A sensor device includes a first light emitter that emits light with a wavelength from a first spectral range, a second light emitter that emits light with a wavelength from a second spectral range, a first light detector configured to detect light with a wavelength from the first spectral range, but not to respond to light with a wavelength from the second spectral range, and a second light detector configured to detect light with a wavelength from the first spectral range and light with a wavelength from the second spectral range, wherein a distance between the first light emitter and the first light detector is smaller than a distance between the second light emitter and the second light detector.