Reflective Optical Sensing with Tunable Wavelengths for Physiological Signals
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Solution Overview
Problem
Existing non-intrusive physiological signal measuring devices face challenges in accurately measuring physiological parameters due to limitations in wavelength adjustment and spectral analysis, leading to inaccuracies in absorption and scattering parameter analysis.
Innovation Solution
A physiological signal measuring device and method that utilizes a light-emitting module and a light sensing module with a controller to adjust the wavelength of emitted light by varying the driving current and/or temperature, allowing for the construction of spectral distribution curves to accurately analyze absorption and scattering parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a non-intrusive reflective optical measuring device emits light at fixed wavelength to illuminate skin and receive reflected light, then the device structure is simple, but the accuracy of physiological signal measurement is insufficient due to limited spectral analysis capability
Solution Approach 1:
The patent applies dynamics by making the light source wavelength adjustable rather than fixed. The controller dynamically changes the driving current of the light-emitting diode to emit light at different wavelengths during different measurement periods, enabling spectral distribution curve construction for accurate physiological parameter analysis while maintaining a single diode structure
Solution Approach 2:
The patent changes the wavelength parameter of the emitted light by adjusting the driving current of the light-emitting diode. By varying the wavelength parameter across multiple measurement periods, the system constructs spectral distribution curves that enable accurate analysis of absorption and scattering parameters, resolving the contradiction between measurement accuracy and device simplicity
2Measurement precision
If the device uses a single light-emitting diode with fixed wavelength, then the device complexity is low, but the spectral distribution curve construction is incomplete leading to inaccurate absorption and scattering parameter analysis
Solution Approach 1:
The system dynamically adjusts the wavelength of the single light-emitting diode across multiple measurement periods rather than using multiple fixed-wavelength diodes. This dynamic wavelength switching enables complete spectral distribution curve construction with a single component, achieving accurate physiological parameter analysis without increasing device complexity
Solution Approach 2:
The single light-emitting diode is made multi-functional by enabling it to emit at multiple wavelengths through dynamic current adjustment. This universal light source performs the function of multiple specialized diodes, constructing complete spectral distribution curves while maintaining device simplicity and reducing component count
3Measurement precision
If the device adjusts wavelength by varying driving current, then the spectral analysis capability is improved, but the measurement time increases due to multiple measurement periods required for spectral curve construction
Solution Approach 1:
The system employs periodic measurement periods where the light-emitting diode emits light at different wavelengths in sequence. Each period contributes one spectral data point, and after N periods, a complete spectral distribution curve is constructed. This periodic approach enables accurate spectral analysis while maintaining efficient measurement through systematic progression
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
Enables precise analysis of physiological signals such as blood glucose, blood oxygen, and heart rate by generating and receiving light at varying wavelengths, reducing the need for multiple diodes and diodes, thus enhancing accuracy and cost-effectiveness.
Implementation Method 1
The light-emitting module includes a light-emitting unit configured to generate emitted light according to a first control signal in each measurement period
Implementation Method 2
adjust the wavelength of the emitted light by varying the driving current and/or temperature
Implementation Method 3
The light sensing module includes a sensing unit configured to receive reflected light corresponding to the emitted light in each of the measurement periods
Implementation Method 4
emit light to illuminate the skin of a user and reach the tissue inside the skin
Implementation Method 5
analyze an absorption parameter and a scattering parameter of a physiological tissue
Data Source
AI summary
A physiological signal measuring device is provided. The physiological signal measuring device includes a light-emitting module, a light sensing module, and a controller. The light-emitting module includes a light-emitting unit configured to generate emitted light according to a first control signal in each measurement period. The light sensing module includes a sensing unit configured to receive reflected light corresponding to the emitted light in each of the measurement periods. The controller is configured to change the first control signal in each of the measurement periods to change a wavelength of the emitted light, and obtain an optical parameter analysis result corresponding to the wavelength of the emitted light according to the reflected light. The controller is configured to obtain a physiological signal corresponding to at least one physiological parameter according to a spectral distribution curve composed of the optical parameter analysis results of the measurement periods.