Skin Spectroscopy Path Length Control for Stable Biomarker Detection
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Solution Overview
Problem
Existing optical spectroscopy methods face challenges in achieving an optimal path length for non-invasive blood biochemistry measurements through skin, particularly in the mid-infrared and near-infrared ranges, due to high water absorption and scattering, leading to signal attenuation and low signal-to-noise ratio.
Innovation Solution
An apparatus is designed to control the effective optical path length of diffusely scattered light through skin tissue using a path length control part, which includes mechanical compression and spectral sensors to optimize the path length for accurate analyte detection, incorporating illumination and collection optics to maximize light collection and reduce scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the optical path length is increased to improve signal collection for biomarker detection, then the signal-to-noise ratio deteriorates due to high water absorption and scattering in skin tissue
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the optical path length through mechanical compression of skin tissue. The compression force is controlled to achieve an optimal path length that balances signal collection with minimizing water absorption and scattering losses, thereby maintaining measurement precision while maximizing signal quantity
Solution Approach 2:
The system employs dynamic control of the optical path length by applying variable mechanical compression to the skin tissue. The compression level can be adjusted in real-time to optimize the effective path length for different measurement conditions, transforming a static measurement system into a dynamically adaptable one that maintains optimal performance across varying tissue properties
2Measurement precision
If the optical path length is decreased to reduce water absorption and scattering, then the signal collection efficiency deteriorates
Solution Approach 1:
The patent resolves this contradiction by changing the optical path length parameter to an optimal intermediate value through controlled mechanical compression. This optimized path length is sufficient to collect adequate signal for detection while remaining short enough to minimize the detrimental effects of water absorption and scattering in the skin tissue
3Length of stationary object
If diffuse reflectance is used to achieve optimal path length, then surface reflection and stray light increase causing measurement instability
Solution Approach 1:
The patent extracts and eliminates the problematic surface reflection component by using transmission geometry through compressed skin tissue rather than diffuse reflectance. This measurement geometry separates the desired transmitted signal from the harmful surface stray light, thereby improving signal stability while maintaining optimal path length control
Solution Approach 2:
The mechanical compression apparatus acts as an intermediary that controls the optical path length through the skin tissue. This intermediary mechanism enables precise path length adjustment while maintaining stable transmission conditions, mediating between the light source and detector to achieve both optimal path length and signal stability
4Length of stationary object
If diffuse reflectance is used for measurement, then optical signal loss increases due to random light path scattering
Solution Approach 1:
The patent converts the harmful effect of light scattering into a beneficial measurement mode by using transmission geometry. Instead of relying on random back-scattering that causes signal loss, the system measures the light that successfully transmits through the compressed tissue, transforming the scattering challenge into a transmission-based measurement that directly quantifies the optical properties of the tissue
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
The apparatus achieves a controlled optical path length for improved signal-to-noise ratio, enabling precise non-invasive measurement of blood biochemicals by optimizing the path length for specific wavelengths, enhancing the detection of biomarkers like glucose and blood alcohol.
Implementation Method 1
control an effective optical path length of diffusely scattered light non-invasively transmitted through skin tissue
Implementation Method 2
obtain a spectrum of an analyte of the skin tissue under test based on the diffusely scattered light
Data Source
AI summary
Aspects relate to mechanisms to control the effective optical path length through skin tissue for non-invasive optical spectroscopy measurements. An apparatus can include a path length control part configured to control the effective optical path length of diffusely scattered light transmitted through skin tissue to produce a target effective optical path length. The apparatus may further include a spectral sensor, a detector, and a light source configured to produce input light directed towards the path length control part or the spectral sensor. The detector is configured to obtain a spectrum of an analyte under test based on the diffusely scattered light. The spectral sensor is configured to either receive the input light, produce modulated light based on the input light, and direct the modulated light to the skin tissue, or to receive the diffusely scattered light from the skin tissue and obtain the spectrum using the detector.