Humidity Control Layer for Optical Sensor Calibration

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Solution Overview

Problem

Conventional optical sensors require wet calibration, which limits sensor shelf-life and complicates cassette design, and is sensitive to ambient humidity variations, affecting accuracy and reproducibility.

Innovation Solution

A dry-calibrated, multi-layered sensor architecture with a humidity control layer and spreading layer, using a ratio of dry and wet fluorescence intensities for analyte concentration measurement, allowing for consistent calibration across different humidity environments and sample types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wet calibration method is used, then sensor calibration accuracy is improved, but sensor shelf-life is reduced and cassette design complexity increases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsensor shelf-life
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The sensor is pre-calibrated in a dry state during manufacturing, eliminating the need for wet calibration before use. This preliminary calibration action extends sensor shelf-life by allowing storage without calibration solution while maintaining calibration accuracy through the dry-to-wet ratio measurement method.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the calibration parameter from wet-state fluorescence intensity to the ratio of wet-to-dry fluorescence intensities. This parameter transformation allows calibration to be performed in a dry state, fundamentally resolving the contradiction between calibration accuracy and shelf-life extension.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If wet calibration method is used, then sensor calibration accuracy is improved, but device complexity and cost are increased

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcassette design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Calibration is performed preliminarily during sensor manufacturing in a dry state, eliminating the need for complex wet calibration storage systems. This simplifies cassette design by removing the requirement for calibration solution reservoirs and associated mechanical components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts the calibration function from the operational use phase to the manufacturing phase. By taking out the calibration action and performing it beforehand in a dry state, the system eliminates complex storage and handling requirements for calibration solutions.

Inventive Principle:
Principle #2Taking out (Extraction)

3Duration of action of stationary object

If dry calibration method is used, then sensor shelf-life is extended and cassette design is simplified, but measurement precision is reduced due to humidity sensitivity

Engineering Contradiction:
Improvesensor shelf-lifeVSAvoidcalibration signal stability
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The measurement parameter is changed from absolute fluorescence intensity to the ratio of wet-to-dry fluorescence intensities. This parameter transformation inherently compensates for humidity variations, as both numerator and denominator are affected similarly by ambient conditions, maintaining measurement precision while enabling dry calibration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dry fluorescence intensity measurement serves as a reference feedback that allows the system to compensate for ambient humidity effects. By comparing wet-state intensity against the pre-established dry-state baseline, the system maintains calibration accuracy across varying environmental conditions.

Inventive Principle:
Principle #23Feedback

4Device complexity

If humidity control is not implemented, then device complexity is reduced, but measurement precision deteriorates under varying humidity conditions

Engineering Contradiction:
Improvesensor structure complexityVSAvoidfluorescence intensity consistency
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Instead of controlling humidity physically, the invention changes the measurement parameter to a humidity-insensitive form (the ratio of wet-to-dry intensities). This mathematical transformation eliminates the need for physical humidity control mechanisms while maintaining fluorescence intensity consistency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces potential mechanical humidity control systems with an optical measurement approach that uses fluorescence intensity ratios. This substitution eliminates complex mechanical humidity regulation while achieving the same goal of measurement consistency under varying humidity conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 accurate, reproducible measurement of analyte concentrations in various samples across different humidity conditions without the need for wet storage, extending sensor shelf-life and simplifying cassette design, while reducing costs.

Implementation Method 1

a water-insoluble, porous matrix, including a plurality of channels or through holes at least some of which extend from one side of the layer to an opposing side; and (b) one or more water-soluble, solid, polymeric substances that fill a substantial portion of the plurality of channels or through holes

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

one or more fluorescence optical sensors to measure the intensity of light emitted from fluorescent dyes exposed to a specific analyte

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP2094377B1Spreading layer and humidity control layer for enhancing sensor performance
Publication Date: 2018.02.21 OPTI MEDICAL SYSTEMS INC
  • EP2094377B1 patent drawingFigure 1~2
  • EP2094377B1 patent drawingFigure 3A~4

AI summary

The invention is directed to optical sensors for measuring clinically relevant analytes, their methods of manufacture, and their various uses. In an effort to develop a dry calibration method for the optical sensors of the invention it is discovered that water content inside or in the immediate vicinity of a such a sensor can have a major impact on fluorescence intensity (i.e., a sensor's response in the dry state). Thus, one of the objectives of the invention is the elimination of the bias of sensor responses measured at different humidity environments. The invention concerns a multi-layered laminate comprising inter alia a humidity control layer and a spreading layer. Said layers comprise a water-insoluble porous matrix, including a plurality of channels or through-holes at least some of which extend from one side of the layer to an opposing side, a portion of said holes or channels being filled with a water-soluble, solid, polymeric substance.