Spatially Resolved Optical Sensor for Absorption Scattering Separation
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Solution Overview
Problem
Current spatially resolving sensors face challenges in accurately determining substance quantities in biological tissues and cloudy mixtures due to the interference of scattering and absorption coefficients, requiring multiple backscatter signals to separate these components effectively.
Innovation Solution
A sensor design with multiple radiation sources and detectors at varying distances to measure diffuse reflection, utilizing the Monte Carlo simulation for radiation propagation assumptions, and selecting specific wavelengths to maximize path length and minimize interference, allowing for independent determination of absorption and scattering coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single backscattering signal is measured, then the measurement process is simple, but the absorption coefficient and concentration of the target substance cannot be clearly determined due to interference from scattering effects
Solution Approach 1:
The patent segments the measurement process by recording backscattering signals at multiple distances (e.g., 1mm, 2mm, 3mm, 4mm, 5mm) from the radiation source. Each distance provides an independent signal that samples different depths and path lengths within the turbid medium. This segmentation of the measurement space allows the system to separate the contributions of absorption and scattering by analyzing how the backscattering intensity varies with distance, thereby resolving the contradiction between measurement simplicity and precision.
2Measurement precision
If multiple backscattering signals at different distances are measured, then absorption and scattering coefficients can be separated, but the device complexity and measurement effort increase
Solution Approach 1:
The patent introduces the dimension of distance by placing detectors at multiple predetermined distances from the radiation source along the optical path. This transforms a single-point measurement into a multi-point spatial measurement. By adding this spatial dimension, the system can differentiate between absorption and scattering effects, as each distance provides information about light transport at different path lengths and depths, enabling coefficient separation without requiring complex spectral or temporal modulation.
Solution Approach 2:
The patent employs predetermined distances between the radiation source and detectors that are selected based on theoretical models (such as the diffusion approximation) and Monte Carlo simulations. These distances are pre-optimized to maximize the information content for separating absorption and scattering coefficients. By performing this optimization in advance, the system reduces the complexity of real-time measurement and data processing, as the geometric configuration is already tailored for optimal coefficient separation.
3Ease of manufacture
If the sensor is designed for mass production, then manufacturing cost and scalability improve, but calibration transfer accuracy between individual sensors may deteriorate
Solution Approach 1:
The patent utilizes predetermined distances between radiation source and detectors that are theoretically optimized based on diffusion approximation and Monte Carlo simulations. These fixed geometric parameters are designed to maximize the information content for separating absorption and scattering coefficients. By establishing these parameters during the design phase rather than adjusting them during calibration, the system enables mass production with consistent performance across units, reducing the need for individual calibration while maintaining measurement precision.
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 precise and sensitive quantification of target substances by maximizing light distribution within the target volume and correcting for interfering substances, achieving accurate concentration determination in biological tissues and mixtures.
Implementation Method 1
The concentration of a substance to be determined can be determined using the absorption of the substance: μa = c • epsilon
Implementation Method 2
the diffuse reflection recorded in the spatially resolved measurement depends on the absorption coefficient μa and the scattering coefficient μs in the case of turbid (scattering) mixtures of substances
Implementation Method 3
measuring diffuse reflection (backscattering) at several different distances from a spatially limited radiation source
Data Source
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AI summary
The invention relates to an optical sensor device which measures in a spatially resolving manner. In order to devise such a sensor device with which a contacting measurement of the article to be measured can be carried out and which can be mass-produced, the sensor device is designed such that a transfer of the calibration onto individual sensor devices is possible with high accuracy. According to certain embodiments of the design of the sensor device and of the evaluation methods, interferences with the measurement of the amount of the target substance are minimized.