VCSEL Array Raman Probe for Non-Invasive Glucose Monitoring
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Solution Overview
Problem
Current non-invasive glucose monitoring devices using Raman spectroscopy face challenges in speed, accuracy, and precision, particularly for diabetics who need frequent and reliable blood sugar level measurements.
Innovation Solution
The use of vertical-cavity surface-emitting lasers (VCSELs) in a spatially offset Raman spectroscopy configuration allows for non-invasive in vivo measurement of glucose in interstitial fluid, with VCSELs arranged in rings or arrays around detectors to vary analysis depth without moving parts, and includes temperature stabilization and wavelength control for improved spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Raman spectroscopy devices are used for non-invasive glucose monitoring, then measurement capability is provided, but speed, accuracy, and precision are insufficient for frequent diabetic monitoring
Solution Approach 1:
The device segments the Raman spectroscopy measurement into multiple wavelength channels using a spectrometer with diffraction grating, allowing simultaneous detection of multiple spectral components. This segmentation enables more precise glucose concentration determination by analyzing the full spectral fingerprint rather than single wavelength points.
Solution Approach 2:
The patent employs multiple VCSELs operating at different wavelengths (780nm, 830nm, 850nm, 870nm, 940nm, 980nm) to excite Raman scattering at various energy levels. By changing the excitation wavelength parameter, the system accesses different Raman shift regions, improving measurement precision through multi-parameter spectral analysis.
2Productivity
If Raman spectroscopy is used for non-invasive measurement, then glucose monitoring capability is achieved, but measurement speed is insufficient for frequent monitoring needs
Solution Approach 1:
The VCSEL array enables continuous spectral scanning across multiple wavelengths without mechanical moving parts. The electronic tuning of VCSEL wavelengths allows rapid sequential measurement at different spectral points, maintaining continuous useful action and improving measurement speed for frequent monitoring.
Solution Approach 2:
The patent replaces mechanical wavelength tuning mechanisms with electrically controllable VCSELs. This substitution eliminates mechanical inertia and moving parts, enabling rapid wavelength switching and significantly improving measurement speed for frequent diabetic monitoring needs.
3Adaptability or versatility
If spatially offset Raman spectroscopy is implemented, then analysis depth can be varied, but device complexity increases with multiple VCSELs and detectors
Solution Approach 1:
The VCSEL array serves multiple functions: different wavelengths provide both spatial offset for depth variation and Raman excitation for molecular identification. The same VCSELs that provide wavelength diversity also enable depth adjustment through spatial offset Raman spectroscopy, reducing overall device complexity through multi-functionality.
Solution Approach 2:
The patent merges the wavelength selection function and depth control function into a single VCSEL array system. By combining these functions in one component array, the device reduces complexity compared to having separate mechanisms for wavelength tuning and depth adjustment.
4Measurement precision
If temperature stabilization and wavelength control are added, then spectral analysis accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The system incorporates self-regulation through temperature stabilization circuits that automatically maintain VCSEL operating temperatures, and wavelength control mechanisms that self-adjust for drift. This self-service approach improves spectral accuracy while reducing the need for complex external calibration systems.
Solution Approach 2:
The patent implements feedback control for temperature stabilization and wavelength monitoring. Sensors detect temperature and wavelength deviations, and control circuits adjust VCSEL operating parameters to maintain accuracy. This feedback mechanism improves measurement precision while using standard electronic control components that are relatively easy to manufacture.
Data Source
AI summary
The present invention relates to an apparatus and method for non-invasive in vivo measurement, by Raman spectroscopy, of glucose present in interstitial fluid in the skin of a subject. The apparatus comprises at least one detector; a plurality of vertical-cavity surface-emitting lasers spatially distributed around the at least one detector, for irradiating the skin of a subject; wherein the at least one detector is configured to receive Raman scattered radiation transmitted from the sample in response to the received radiation from the vertical-cavity surface-emitting lasers.