Multiplexed Photodetector Array for Pulse Oximetry Signal Quality
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Solution Overview
Problem
Pulse oximetry sensors face challenges in maintaining effective light transmission due to tissue movement and anatomical barriers, leading to signal artifacts, and the use of multiple photodetectors increases complexity and manufacturing costs with numerous communication lines.
Innovation Solution
A multiplexed array of photodetectors is employed, with multiplexor control circuitry either in the monitor or sensor, to select and output the best quality signal, reducing the number of communication lines needed and allowing simultaneous measurement of multiple physiological characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple photodetectors are used to improve signal quality and overcome tissue movement issues, then measurement reliability is improved, but device complexity and manufacturing cost increase due to numerous communication lines
Solution Approach 1:
Multiple photodetector elements are combined into a single integrated photodetector array that shares common communication lines with the monitor. The array is controlled as a unified device rather than as individual detectors, reducing the number of communication lines while maintaining multiple detection capabilities for improved signal quality and reliability.
Solution Approach 2:
The photodetector array is designed to perform multiple functions: it can detect light from different wavelengths simultaneously, compensate for tissue movement through multiple measurement points, and provide redundant measurement paths. This multi-functionality is achieved within a single array structure that shares communication infrastructure, avoiding the need for separate communication lines for each function.
2Reliability
If every photodetector has a dedicated communication line to the monitor, then signal transmission reliability is improved, but the cable size and weight increase, causing sensor dislodgement
Solution Approach 1:
Multiple communication lines that would individually connect each photodetector to the monitor are merged into a shared communication infrastructure. The photodetector array communicates with the monitor through common lines, significantly reducing cable weight and size while maintaining reliable signal transmission through the integrated array architecture.
3Reliability
If multiple photodetectors are used to overcome anatomical barriers and maintain contact, then measurement reliability is improved, but manufacturing cost and defect likelihood increase with more communication lines
Solution Approach 1:
The patent merges multiple photodetector elements into a single integrated array structure that uses shared communication lines. This integration reduces the total number of communication lines required, thereby lowering manufacturing complexity, reducing the likelihood of manufacturing defects, and decreasing overall system cost while maintaining the ability to obtain consistent measurements through multiple detection points.
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 approach enhances the efficiency of pulse oximetry systems by maintaining signal quality and reducing manufacturing costs, enabling continuous and accurate monitoring of physiological parameters with minimal additional hardware or communication lines.
Implementation Method 1
a detector that photoelectrically detects the amount of light that has been lost due to absorption and/or scattering by the tissue
Data Source
AI summary
The present disclosure relates generally to medical devices and, more particularly, to optical medical sensors used for sensing physiological characteristics of a patient. In one embodiment, a system includes a physiological sensor having a photodetector array with a plurality of photodetectors configured to receive light from patient tissue. The physiological sensor also includes a multiplexor configured select and output a signal from the photodetector array. The physiological sensor may also include a signal analyzer configured to determine the signal quality for each of the output signals of the photodetector array and select an output signal, based on the signal quality determination, for the calculation of a physiological parameter of the patient. In another embodiment, a system includes a pulse oximetry sensor having a multiplexed array of photodetectors configured to receive light from patient tissue. The system also includes a pulse oximetry monitor having a multiplexor driver to control the multiplexed array of photodetectors as well as a processor configured to control the multiplexor driver and receive the output signals from the array of photodetectors. The processor is also configured to determine the signal quality of each of the output signals from the array of photodetectors, select an output signal based on the signal quality determination, and use the selected signal to calculate a physiological parameter of a patient.