Opto-physiological Sensor with Multi-Wavelength Segmented Light Sources
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current photoplethysmography (PPG) systems are inaccurate due to neglecting light scattering effects, motion-induced artifacts, and skin-related factors like sweat and creams, and lack the ability to simultaneously measure a wide range of physiological parameters, including blood oxygen saturation.
Innovation Solution
An opto-physiological sensor is designed with an optimal optical configuration determined by modeling tissue properties, featuring light sources of different wavelengths positioned at specific distances from a photodetector, and a controller to adjust for tissue tilt and signal quality, enabling accurate measurement of various physiological parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PPG systems use simple illumination sources and photodetectors, then the device complexity is low, but the measurement precision is poor due to inability to account for light scattering, motion artifacts, and skin-related factors
Solution Approach 1:
The illumination source is segmented into multiple independent light sources emitting at different wavelengths, with each source positioned at specific distances from the photodetector. This segmentation allows the system to measure multiple physiological parameters simultaneously and reduces motion artifacts by isolating specific optical paths for specific measurements.
Solution Approach 2:
The patent introduces spatial dimension by positioning light sources at different distances from the photodetector, creating concentric circular arrangements. This adds a depth dimension to the optical measurement, enabling the system to distinguish between superficial and deep tissue signals and improve measurement precision across different tissue types.
2Adaptability or versatility
If the sensor uses multiple light sources at different wavelengths and positions to measure various physiological parameters, then the adaptability increases, but the device complexity increases
Solution Approach 1:
The sensor system is designed with multiple light sources at different wavelengths and positions that can simultaneously measure multiple physiological parameters including heart rate, blood oxygen saturation, and other tissue opto-physiological properties. This multi-functional design allows a single sensor to serve various monitoring purposes across different tissue types and conditions.
Solution Approach 2:
The system utilizes parameter changes by varying the wavelengths of light sources and their positions at different distances from the photodetector. These parameter variations enable the sensor to optimize measurements for different physiological parameters and tissue types, enhancing adaptability without requiring separate sensors for each measurement type.
3Measurement precision
If light sources are positioned closer to the photodetector, then the signal strength increases, but the ability to measure deep tissue properties decreases
Solution Approach 1:
The illumination system is segmented into multiple light sources positioned at different distances from the photodetector. This segmentation creates distinct optical paths that can be selectively activated based on the measurement requirement, allowing the system to optimize between signal strength for superficial tissues and penetration depth for deep tissue measurements.
Solution Approach 2:
By adding the spatial dimension of light source positioning at different distances, the system creates a multi-depth optical measurement capability. This dimensional approach allows simultaneous optimization of signal strength for close-range tissues and penetration depth for deeper tissues through selective activation of appropriately positioned light sources.
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 sensor provides reliable and accurate monitoring of heart rate, blood oxygen saturation, and other parameters, improving accuracy and adaptability across different tissue types and conditions, while reducing motion artifacts and skin-related interference.
Implementation Method 1
The principle uses an illumination source and a photodetector to measure changes in intensity as light is passed through or reflected from body tissue
Implementation Method 2
determining a separation of each of a plurality of light sources from a photodetector, based on modelled optical path lengths for light travelling from each light source, through the body tissue type to be monitored, to the photodetector
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4B
AI summary
A method of assembling an opto-physiological (OP) sensor comprises: (i) modelling the opto-physiological properties of at least one body tissue type to be monitored; (ii) determining, through application of the model, an optimal optical design for an opto- physiological (OP) sensor operable to monitor the opto-physiological properties of the at least one body tissue type; and (iii) making the OP sensor to the determined optical design. The optimal optical design for the OP sensor comprises: (i) determining the optimum separation of each of a plurality of light sources from a photodetector, based on modelled optical path lengths for light travelling from each light source, through the body tissue type to be monitored, to the photodetector; and (ii) locating light sources of different wavelengths at different distances from the photodetector.