Noninvasive Sensor System for Blood Analyte Measurement
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Solution Overview
Problem
Existing noninvasive medical devices struggle to accurately measure blood analytes like glucose using spectroscopic analysis, particularly due to challenges in signal gain and noise reduction at specific wavelengths.
Innovation Solution
The development of a noninvasive sensor system that employs multi-stream infrared and near-infrared spectroscopy, featuring a point optical source and multiple photodetectors with varying path lengths, coupled with advanced front-end interfaces using switched-capacitor circuits or transimpedance amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectroscopic analysis is used to measure blood analytes noninvasively, then measurement capability is provided, but signal gain is insufficient and noise is high at specific wavelengths
Solution Approach 1:
The optical detection system is divided into multiple independent photodetectors, each optimized for specific wavelength ranges (visible, near-infrared, short-wave infrared). This segmentation allows each detector to operate at its optimal wavelength with dedicated signal processing, thereby improving signal gain and reducing noise for specific blood analyte measurements.
Solution Approach 2:
The system dynamically adjusts optical parameters by switching between different wavelength ranges and modulating light intensity based on the specific analyte being measured. The front-end interface circuits dynamically adjust gain and filtering parameters to optimize signal-to-noise ratio at different wavelengths, resolving the contradiction between measurement capability and signal reliability.
2Adaptability or versatility
If multiple photodetectors with varying path lengths are used, then measurement capability for multiple analytes is improved, but device complexity increases
Solution Approach 1:
A single integrated sensor unit incorporates multiple photodetectors covering different wavelength ranges, enabling the device to measure multiple blood analytes (glucose, oxygen, methemoglobin, etc.) through one unified interface. The front-end circuitry provides universal signal processing capabilities that handle different detector types and wavelength ranges, reducing overall system complexity despite the multi-functional capability.
Solution Approach 2:
Multiple photodetectors and their corresponding signal processing circuits are merged into a single integrated sensor unit with a unified readout architecture. The front-end interface combines multiple detector signals through common signal processing stages, reducing the complexity that would otherwise arise from separate measurement systems for each analyte.
3Reliability
If advanced front-end interfaces with switched-capacitor circuits or transimpedance amplifiers are used, then signal gain is enhanced and noise is reduced, but device complexity increases
Solution Approach 1:
The front-end interface replaces complex mechanical signal conditioning components with electronic switched-capacitor circuits and transimpedance amplifiers that provide superior signal gain and noise rejection. These electronic circuits achieve better signal-to-noise ratio through electrical impedance matching and active noise cancellation, improving reliability without requiring complex mechanical filtering or signal processing stages.
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 enables precise noninvasive measurement of blood analytes such as glucose, oxygen, and methemoglobin by enhancing signal gain and reducing noise, thereby improving the accuracy and reliability of physiological parameter monitoring.
Implementation Method 1
an optical source configured to emit optical radiation at least at wavelengths between about 1600 nm and about 1700 nm
Implementation Method 2
a plurality of photodetectors configured to detect the optical radiation from the optical source after attenuation by the tissue of the measurement site and each output a respective signal stream
Implementation Method 3
After attenuation by tissue and fluids of the measurement site, a photodetection device(s) detects the attenuated light
Data Source
AI summary
The present disclosure relates to noninvasive methods, devices, and systems for measuring various blood constituents or analytes, such as glucose. In an embodiment, a light source comprises LEDs and super-luminescent LEDs. The light source emits light at at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm. In an embodiment, the detector comprises a plurality of photodetectors arranged in a special geometry comprising one of a substantially linear substantially equal spaced geometry, a substantially linear substantially non-equal spaced geometry, and a substantially grid geometry.