Multi-Zone Optical Reflectance for Layer-Specific Absorption

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Solution Overview

Problem

Existing diffuse reflectance spectroscopy methods struggle to accurately estimate analyte concentrations in non-homogeneous objects with a superficial layer, as changes in the superficial layer can be misattributed to the deep layer, leading to incorrect diagnoses, particularly in cases like cerebral hypoxia.

Innovation Solution

A method and device that separate the contributions of superficial and deep layers by using multiple detection zones and calibration functions to estimate absorption coefficients, accounting for temporal variations in the superficial layer, allowing for accurate estimation of analyte concentrations in both layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional diffuse reflectance spectroscopy is used to measure light absorption in a non-homogeneous object with a superficial layer, then the measurement process is simple, but the estimation of analyte concentrations in the deep layer becomes inaccurate due to contamination by superficial layer contributions

Engineering Contradiction:
Improveaccuracy of analyte concentration estimationVSAvoidcomplexity of measurement process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement process is segmented into multiple detection zones at different distances from the illumination zone. The first detection zone (closer) primarily detects photons that have traveled through the superficial layer, while the second detection zone (farther) detects photons that have penetrated deeper. This spatial segmentation allows separate characterization of superficial and deep layer optical properties, resolving the contamination problem.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a spatial dimension (detection distance) to differentiate between layers. By detecting photons at multiple distances from the illumination zone, the method transforms a one-dimensional absorption measurement into a multi-dimensional measurement that provides depth-resolved information about analyte concentrations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the superficial layer is not considered in the analysis, then the measurement process remains simple, but errors are introduced in estimating the analyte concentrations of the deep layer

Engineering Contradiction:
Improveaccuracy of deep layer analyte concentrationVSAvoidcomplexity of data processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The method performs preliminary characterization of the superficial layer by detecting photons at the first detection zone before analyzing the deep layer. This preliminary action estimates the superficial layer's absorption and scattering properties, which are then used to correct the deep layer measurements, eliminating the need for complex iterative deconvolution.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The photons detected at intermediate distances serve as intermediaries that carry information about the superficial layer's optical properties. By measuring absorbance at multiple distances, the method uses these intermediate measurements as mediators to separate and quantify the superficial and deep layer contributions independently.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple detection zones are used to separate superficial and deep layer contributions, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveaccuracy of layer-specific analyte concentrationVSAvoidnumber of detection zones
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each detection zone is assigned a specific function: the first detection zone is optimized for measuring superficial layer properties, while the second detection zone is optimized for measuring deep layer properties. This local specialization of detection zones allows accurate layer-specific measurements without requiring complex multi-parameter detection at every zone.

Inventive Principle:
Principle #3Local quality

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 method and device effectively distinguish between superficial and deep layer variations, providing precise estimates of analyte concentrations over time, reducing the risk of misdiagnosis by accurately separating the contributions of each layer.

Implementation Method 1

Light propagation properties generally include absorption properties and/or light scattering properties

Methodology Applied
Scientific EffectLight propagation: Light

Implementation Method 2

absorption properties and/or light scattering properties. These include absorption or scattering coefficients

Methodology Applied
Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

absorption properties and/or light scattering properties. These include absorption or scattering coefficients

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 4

detecting photons backscattered by the analyzed object, at a distance from the incident beam

Methodology Applied
Scientific EffectBackscattering: Scattering

Data Source

PatentEP4394360B1Method for analysing an object having several superposable layers by optical reflectance measurements
Publication Date: 2025.09.17 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4394360B1 patent drawingFigure 1A~1B
  • EP4394360B1 patent drawingFigure 2
  • EP4394360B1 patent drawingFigure 3~4

AI summary

Method for determining a change in the absorption properties of an object (20) between a first instant (t1) and a second instant (t2), the object having a surface layer (L1) and a deep layer (L2), the method comprising: - a) illuminating the object with a light source (10) emitting an illumination beam (11) forming a zone (12) on the surface of the object; - b) detecting photons backscattered by the object, the detected backscattered photons emanating from a detection zone (141, 142, 143), the detection zone being located at a detection distance from the illumination zone, the detection distance being chosen from, in ascending order: • a first detection distance (d1), forming a first detection zone; • a second detection distance (d2) forming a second detection zone; • a third detection distance (d3), forming a third detection zone;