Reflective Mirror Face Decouples Fluorescence Optics

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Solution Overview

Problem

Current fluorescence detection systems for microfluidic assays face challenges such as instability due to photoquenching, thermo-convection, bubbles, and high costs associated with confocal optics, making them unsuitable for portable and robust detection outside controlled laboratory settings, especially in remote locations where molecular diagnostics are needed for infectious diseases.

Innovation Solution

A reflective mirror face formed on a heating block interfaces with a thermo-optical window in the microfluidic cartridge, decoupling excitation and emission optics, and using a scanning objective lens to improve sensitivity and reduce noise, allowing for efficient fluorescence detection with lower-cost optics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If confocal optics are used for fluorescence detection, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefluorescence detection sensitivityVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the confocal detection requirement and replaces it with a simpler widefield illumination system combined with computational imaging techniques. The excitation source illuminates the entire detection chamber uniformly, and image processing algorithms selectively extract in-focus signal information, eliminating the need for complex confocal optical components while maintaining detection precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses computational copying of the confocal effect through software algorithms that simulate confocal detection behavior. By capturing widefield images and applying deconvolution and focal plane extraction algorithms, the system recreates confocal-like detection precision without requiring confocal optical hardware, significantly reducing device complexity and cost.

Inventive Principle:
Principle #26Copying

2Measurement precision

If confocal optics are used for fluorescence detection, then measurement precision is improved, but the equipment becomes less suitable for portable use

Engineering Contradiction:
Improvefluorescence detection sensitivityVSAvoidinstrument portability
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent removes the heavy and complex confocal optical components (scanning mirrors, pinholes, complex lens systems) and replaces them with a lightweight LED-based widefield illumination system. The detection chamber is illuminated uniformly, and computational methods extract the necessary focal plane information, dramatically reducing instrument weight and enabling portable deployment in remote settings.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If standard fluorescence detection is used, then device simplicity is maintained, but sensitivity to detect low-abundance targets is insufficient

Engineering Contradiction:
Improveoptical system simplicityVSAvoiddetection limit
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies computational copying of confocal detection precision through image processing algorithms. By capturing widefield fluorescence images and applying deconvolution algorithms that mathematically reconstruct the focal plane distribution, the system achieves confocal-level detection sensitivity using simple widefield optics, thereby improving detection limits without increasing device complexity.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs periodic scanning of the detection chamber at different focal planes using a simple linear translation stage. By sequentially capturing images at multiple depths and applying computational reconstruction, the system enhances sensitivity to low-abundance targets while maintaining optical system simplicity, avoiding the need for complex confocal scanning mechanisms.

Inventive Principle:
Principle #19Periodic action

4Ease of manufacture

If uniform illumination is used across the detection chamber, then ease of manufacture is improved, but photoquenching and thermo-convection increase

Engineering Contradiction:
Improveoptical system fabricationVSAvoidsignal stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements local quality control by using spatially selective illumination patterns rather than uniform illumination. The excitation light is focused primarily on the focal plane containing the sample, with reduced intensity at other depths. This localized excitation approach maintains ease of manufacture using simple optics while minimizing photoquenching and thermo-convection effects that arise from excessive uniform illumination throughout the entire chamber volume.

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

This configuration enhances sensitivity, reduces noise, and improves detection limits, making it suitable for portable and cost-effective molecular diagnostics in remote settings, while maintaining robustness and accuracy in the presence of sample inhomogeneities like bubbles.

Implementation Method 1

A reflective mirror face formed on a heating block interfaces with a thermo-optical window in the microfluidic cartridge

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

using a scanning objective lens to improve sensitivity and reduce noise

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

a fluorescent probe or fluorophore absorbs light having a wavelength or range of wavelengths and becomes excited; and the fluorophore then emits a fluorescent signal

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP2391883B1Portable high gain fluorescence detection system
Publication Date: 2018.03.07 MICRONICS INC
  • EP2391883B1 patent drawingFigure 1
  • EP2391883B1 patent drawingFigure 2
  • EP2391883B1 patent drawingFigure 3A~3B

AI summary

Disclosed is a compact, microprocessor-controlled instrument for fluorometric assays in liquid samples, the instrument having a floating stage with docking bay for receiving a microfluidic cartridge and a scanning detector head with on-board embedded microprocessor for controlling source LEDs, emission signal amplification and filtering in an isolated, low noise, high gain environment within the detector head. Multiple optical channels may be incorporated in the scanning head. In a preferred configuration, the assay is validated using dual channel optics for monitoring a first fluorophore associated with a target analyte and a second fluorophore associated with a control. Applications include molecular biological assays based on PCR amplification of target nucleic acids and fluorometric assays in general, many of which require temperature control during detection. Sensitivity and resistance to bubble interference during scanning are shown to be improved by use of a heating block with reflective mirror face in intimate contact with a thermo-optical window enclosing the liquid sample.