SPAD Optical Glucose Detection Without Invasive Sampling
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Solution Overview
Problem
Conventional methods of measuring blood glucose levels are invasive, causing discomfort and pain, and require complex data processing for accurate detection.
Innovation Solution
A non-invasive glucose monitor using single-photon avalanche diodes (SPAD) with time-resolved spectroscopy and GeSi SPAD arrays, employing dual-SWIR-wavelength light sources and on-chip bandpass filters for direct time-of-flight measurements, reducing the need for computationally heavy data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (finger prick or subcutaneous sensor) are used to measure blood glucose levels, then measurement accuracy is achieved, but user comfort and ease of operation deteriorate due to invasive procedures causing pain and discomfort
Solution Approach 1:
The patent replaces mechanical invasive sensing (needles and sensors inserted into body) with optical non-invasive sensing using light pulses. The system uses optical detectors to measure glucose concentration through light interaction with tissue, eliminating the need for physical intrusion and associated pain/discomfort while maintaining measurement capability
Solution Approach 2:
The patent changes the measurement parameter from direct blood sampling to optical properties of tissue. By measuring how light pulses interact with tissue (absorption, scattering characteristics) and using time-resolved spectroscopy, the system infers glucose concentration without physical contact with blood, thus improving ease of operation while preserving measurement accuracy
2Ease of operation
If time-resolved spectroscopy with SPAD photodetectors is used for non-invasive glucose detection, then ease of operation improves by eliminating invasive procedures, but device complexity increases due to sophisticated optical systems and data processing requirements
Solution Approach 1:
The patent segments the detection process into distinct functional components: light source emission, tissue interaction, photon detection by SPAD array, time-resolved signal separation, and glucose concentration calculation. This segmentation allows each component to be optimized independently and simplifies the overall system architecture while maintaining non-invasive operation
Solution Approach 2:
The patent introduces time-resolved spectroscopy as an intermediary measurement approach. Instead of directly measuring glucose, the system measures temporal characteristics of light scattering/absorption patterns, which serve as intermediaries that correlate with glucose concentration. This intermediary approach simplifies the direct measurement problem while enabling non-invasive detection
3Duration of action of moving object
If conventional continuous glucose monitors with subcutaneous sensors are used, then continuous monitoring capability is achieved, but loss of substance increases due to needle insertion and potential bleeding or infection
Solution Approach 1:
The patent replaces mechanical needle insertion with optical non-invasive sensing. By using light pulses that penetrate tissue without physical breach, the system achieves continuous monitoring capability while completely eliminating blood loss and infection risks associated with subcutaneous sensors
Solution Approach 2:
The patent converts the natural optical properties of tissue (which previously caused signal interference) into beneficial measurement parameters. By measuring time-resolved light scattering patterns, the system uses tissue characteristics as useful signals for glucose detection, transforming what could be interference into the basis for accurate non-invasive measurement
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 fast, reliable, and cost-effective glucose monitoring without invasive procedures, providing accurate glucose concentration measurements through time-domain photon counting signals.
Implementation Method 1
one or more single-photon avalanche diodes configured to receive light pulses having one or more wavelengths that have interacted with biological tissues
Implementation Method 2
the absorption region comprises germanium or germanium containing tin
Implementation Method 3
SPAD photodetectors may provide time-resolved information related to the tissues with direct time-of-flight (dToF) measurements
Data Source
AI summary
Described herein are systems and methods for non-invasive glucose detection using an optical sensing apparatus. The optical sensing apparatus comprises one or more single-photon avalanche diodes (SPADs) and one or more processors. The one or more SPADs may be configured to receive light pulses having one or more wavelengths that have interacted with biological tissues over a plurality of time cycles and convert the light pulses into a plurality of electrical signals. Each of the one or more SPADs may comprise an absorption region formed on a substrate, wherein the absorption region comprises germanium or germanium containing tin, and wherein the substrate comprises silicon. The one or more processors may be configured to identify, for each of the plurality of time cycles, particular time slots representing a time duration that each of the light pulses has interacted with glucose molecules and determine one or more characteristics of glucose molecules.