Multidimensional Optical Sensor for Hemodynamic Monitoring
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Solution Overview
Problem
Conventional wearable devices equipped with one-dimensional optical sensors are unable to accurately verify the proper positioning of the sensor over an artery, detect motion artifacts, or compute values for various health metrics such as pulse transit time, blood pressure, and arterial stiffness, due to their invasive nature and limitations in spatial measurement.
Innovation Solution
A multidimensional optical sensor device that includes a CMOS sensor capable of generating M×N pixel images, paired with illuminators and processing circuitry, allows for non-invasive measurement of hemodynamics by verifying tissue type, detecting correct sensor placement, and resisting motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If one-dimensional optical sensors are used in wearable devices, then the device structure is simple and easy to manufacture, but the device cannot verify proper sensor positioning over arteries and cannot detect motion artifacts
Solution Approach 1:
The patent transitions from one-dimensional optical sensors to two-dimensional array sensors. This dimensional change enables the sensor to capture spatial information across multiple locations simultaneously, allowing verification of proper artery positioning and detection of motion artifacts through spatial pattern analysis of the captured light variations.
Solution Approach 2:
The two-dimensional array sensor divides the sensing area into multiple discrete sensing elements arranged in a grid pattern. Each element independently captures light variations, and the collective data from segmented elements enables spatial analysis to verify artery positioning and distinguish physiological signals from motion artifacts.
2Device complexity
If conventional one-dimensional optical sensors are used, then the device is simple and consumer-friendly, but the device cannot compute values for multiple health metrics such as pulse transit time, blood pressure, and arterial stiffness
Solution Approach 1:
By implementing a two-dimensional array sensor, the device gains the capability to perform multiple measurements simultaneously across different spatial locations. This enables computation of multiple health metrics including pulse transit time (by measuring signal propagation between sensor elements), blood pressure (through pulse wave analysis), and arterial stiffness (via pulse wave velocity calculations), all from a single sensor array.
Solution Approach 2:
The two-dimensional array sensor serves multiple functions: it detects basic physiological parameters like heart rate and blood oxygenation, verifies proper sensor positioning, detects motion artifacts, and enables computation of advanced health metrics. This multi-functionality is achieved through the spatial distribution of sensing elements that can capture various physiological signals simultaneously.
3Ease of operation
If conventional wearable devices assume the optical sensor is located on an artery, then the device operation is simple, but the device cannot distinguish between reflections from blood rushing through arteries and fluctuations from other sources such as environmental light changes and user motion
Solution Approach 1:
The two-dimensional array sensor captures spatial patterns of light variations across multiple sensing elements. By analyzing the spatial distribution and temporal correlation of signals across the array, the system can distinguish between arterial blood flow signals (which produce characteristic spatial-temporal patterns) and artifacts from environmental light changes or user motion (which produce different spatial patterns), thereby eliminating the need to assume proper sensor placement.
Solution Approach 2:
The system uses feedback from the spatial pattern analysis to verify proper sensor positioning and to distinguish signal sources. The processing circuitry continuously monitors the patterns captured by the array and adjusts or validates measurements based on whether the observed patterns match expected arterial signal characteristics, providing reliable discrimination without assuming correct placement.
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 device effectively outputs accurate values for multiple hemodynamic metrics, including arterial heart rate, pulse wave velocity, and blood oxygenation, while being non-invasive and capable of integration into consumer-level devices like wearable fitness trackers.
Implementation Method 1
the optical sensor(s) (which are sensitive to the wavelengths) detect an amount of light not absorbed by human tissue
Data Source
AI summary
A sensor device is described herein. The sensor device includes a multi-dimensional optical sensor and processing circuitry, wherein the multi-dimensional optical sensor generates images and the processing circuitry is configured to output data that is indicative of hemodynamics of a user based upon the images. The sensor device is non-invasive, and is able to be incorporated into wearable devices, thereby allowing for continuous output of the data that is indicative of the hemodynamics of the user.