Non-Invasive Glucose Detection Using Far Infrared and Temperature Compensation
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Solution Overview
Problem
Conventional far infrared detection systems for non-invasive glucose measurement face challenges in achieving high accuracy due to perturbations caused by blackbody emission from system components, which are costly and impractical to mitigate through cryogenic cooling and nitrogen sealing for consumer products.
Innovation Solution
The system employs a temperature-measuring device for each element within the detector's field of view, creating a look-up table to compensate for temperature effects, and a spherical baffle with a gold-plated, polished internal surface to reduce emissivity and prevent stray radiation from reaching the detector, while using changeable optical filters to isolate the desired wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the system is cooled to cryogenic temperature and sealed with dry nitrogen to eliminate blackbody emission perturbations, then measurement accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent changes the operating wavelength parameter from near-infrared to far-infrared region (6-15 microns), where glucose absorption is significantly stronger. This allows the system to operate at room temperature while achieving sufficient measurement accuracy, eliminating the need for cryogenic cooling and complex sealing systems.
Solution Approach 2:
The patent employs room-temperature operational components instead of expensive cryogenic systems. By using standard temperature operation with far-infrared detection, the system replaces costly, complex cryogenic infrastructure with simpler, more affordable components suitable for consumer products.
2Measurement precision
If the baffle reflectivity is enhanced to reduce emissivity, then temperature perturbation is reduced, but stray radiation reflection to the detector increases
Solution Approach 1:
The patent employs a spherical baffle geometry where the inner surface is curved to redirect stray radiation away from the detector. The spherical shape ensures that reflected rays diverge and do not converge on the detector, effectively eliminating stray radiation while maintaining low emissivity through gold plating.
Solution Approach 2:
The baffle is segmented into distinct functional zones: the inner spherical surface for radiation redirection, the gold-plated low-emissivity coating for temperature control, and the overall geometric structure for stray light management. This segmentation allows each surface to be optimized for its specific function.
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 high-accuracy non-invasive glucose measurement by effectively compensating for temperature-related perturbations and minimizing stray radiation, resulting in a robust and practical consumer-friendly device.
Implementation Method 1
A far infrared detection system to analyze and determine, non-invasively, the concentration of a substance in a body
Implementation Method 2
the blackbody emission of any component of the system (mirrors, filters, field limiters, detector, for example) can cause perturbations in the measurement
Implementation Method 3
An optical system is provided and aligned to focus IR radiation emitted by the body on a sensitive area of the detector
Implementation Method 4
A spherical baffle was designed with an internal surface, i.e., the surface of the baffle opposite the detector, that is polished and gold-plated to lower the emissivity. The baffle design eliminates any reflection or multiple reflections from reaching the sensitive area of the detector
Implementation Method 5
enhancing the reflectivity of the baffle creates an additional problem of reflecting stray energy to the detector
Implementation Method 6
Each element of the system within the field of view of the detector and the detector itself has a temperature measuring device such as a thermistor attached to it for the purpose of measuring its temperature
Implementation Method 7
Two changeable optical filters are provided. The first optical filter is aligned in the optical path between the first mirror and the second mirror. The second optical filter is aligned in the optical path between the first mirror and the second mirror
Data Source
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AI summary
A method and apparatus for the noninvasive detection of a concentration of a substance in a body, such as glucose in the human bloodstream is disclosed. The apparatus measures substance concentration by detecting radiation in the far infrared range emitted by the body using an infrared detected in combination with a set of adequate filters. In order to achieve the accuracy required, the radiation values detected by the detector arc corrected for the emissions of the system components. The temperature of each system component including the detector temperature and an ambient temperate is determined using temperature sensors attached to the various system components. These temperatures are correlated with a set of predetermined calibration parameters to correct the detector readings.