Wearable Glucose Measurement With Coded Spectral Illumination
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Solution Overview
Problem
Existing optical characterization and measurement techniques face challenges in efficiently measuring target objects due to limited response light availability and cumbersome calibration requirements, particularly when relying on dispersive optics and demanding signal-processing of the receive-side light signals.
Innovation Solution
The use of a coded light source (CLS) that modulates multiple spectral bins concurrently, allowing for simultaneous decoding and measurement of response light without the need for dispersive optics, reducing the demands on receive-side optics and signal-processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dispersive optics and receive-side signal-processing are used to measure target objects, then spectral measurement capability is achieved, but device complexity and calibration requirements increase
Solution Approach 1:
The patent inverts the conventional approach by moving the spectral encoding function from the receive-side dispersive optics to the transmit-side coded light source. Instead of separating wavelengths optically after interaction with the target, the system encodes different spectral information into different temporal or spatial patterns of the illumination light itself, eliminating the need for complex receive-side dispersive optics.
Solution Approach 2:
The patent replaces mechanical/optical dispersive systems with an electrical/code-based approach. By using coded modulation of the light source and corresponding decoding algorithms, the system substitutes physical wavelength separation mechanisms with computational methods, thereby reducing device complexity while maintaining spectral measurement capability.
2Measurement precision
If dispersive optics are used for spectral measurement, then spectral resolution is achieved, but the amount of response light available for processing is reduced
Solution Approach 1:
The patent inverts the conventional approach by moving the spectral encoding function from the receive-side dispersive optics to the transmit-side coded light source. Instead of separating wavelengths optically after interaction with the target, the system encodes different spectral information into different temporal or spatial patterns of the illumination light itself, eliminating the need for complex receive-side dispersive optics.
3Measurement precision
If conventional spectroscopic methods are used, then spectral analysis is performed, but calibration requirements become cumbersome
Solution Approach 1:
The patent implements self-calibration through the coded modulation scheme. The known encoding patterns applied to the light source serve as built-in reference signals, allowing the system to automatically calibrate itself without requiring external calibration standards or procedures. The decoding process inherently accounts for system characteristics, eliminating separate calibration steps.
4Measurement precision
If receive-side signal-processing is used to analyze target objects, then measurement capability is achieved, but the demands on signal-processing increase
Solution Approach 1:
The patent inverts the conventional approach by moving the spectral encoding function from the receive-side dispersive optics to the transmit-side coded light source. Instead of separating wavelengths optically after interaction with the target, the system encodes different spectral information into different temporal or spatial patterns of the illumination light itself, eliminating the need for complex receive-side dispersive optics.
Solution Approach 2:
The patent performs spectral encoding in advance at the light source before the light interacts with the target. By pre-encoding the spectral information in the illumination patterns, the system simplifies the receive-side processing, which only needs to detect and decode the pre-encoded signals rather than perform complex spectral separation and analysis.
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 signal-to-noise ratio (SNR) and reduces the need for cumbersome calibration, enabling more efficient and stable spectral measurement across various applications, including wearable devices and industrial processes.
Implementation Method 1
The use of a coded light source (CLS) that modulates multiple spectral bins concurrently
Implementation Method 2
the amount of response light available for processing and analysis, e.g., from scattering, reflection, absorption, fluorescence, polarization, or transmission
Implementation Method 3
the amount of response light available for processing and analysis, e.g., from scattering, reflection, absorption, fluorescence, polarization, or transmission
Implementation Method 4
the amount of response light available for processing and analysis, e.g., from scattering, reflection, absorption, fluorescence, polarization, or transmission
Implementation Method 5
the amount of response light available for processing and analysis, e.g., from scattering, reflection, absorption, fluorescence, polarization, or transmission
Implementation Method 6
A photodetector can be used, such as in a camera or spectrometer, to detect the intensity response I[ . . . ] from the target object
Data Source
AI summary
Modulation-encoded light, using different spectral bin coded light components, can illuminate a stationary or moving (relative) target object or scene. Response signal processing can use information about the respective different time-varying modulation functions, to decode to recover information about a respective response parameter affected by the target object or scene. Electrical or optical modulation encoding can be used. LED-based spectroscopic analysis of a composition of a target (e.g., SpO2, glucose, etc.) can be performed; such can optionally include decoding of encoded optical modulation functions. Baffles or apertures or optics can be used, such as to constrain light provided by particular LEDs. Coded light illumination can be used with a focal plane array light imager receiving response light for inspecting a moving semiconductor or other target. Encoding can use orthogonal functions, such as an RGB illumination sequence, or a sequence of combinations of spectrally contiguous or non-contiguous colors.