Pinhole Aperture Camera for Lateral Flow Assay Quantization

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Solution Overview

Problem

Existing devices for evaluating lateral flow assays (LFA) are complex and costly, making them unsuitable for end-users, and require batch and test-specific calibration data, which is difficult to implement in inexpensive systems, limiting their accessibility and accuracy for quantitative and qualitative assessments.

Innovation Solution

A simple, camera-based measuring device with a pinhole or slit diaphragm for imaging, using a CCD line and microcontroller, which is inexpensive, intuitive to use, and capable of evaluating multiple test lines, with wireless transmission of test-specific data via RFID, allowing for quantitative and qualitative analysis without additional optical components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If camera-based devices are used for evaluating lateral flow assays, then measurement accuracy and reproducibility are improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The device is divided into functionally independent modules: a simple optical system with LED light source and photodetector array, a microcontroller unit for signal processing, and a display interface. Each module performs a specific function, allowing the system to achieve professional-grade measurement accuracy without requiring complex integrated systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs inexpensive optical components such as standard LEDs and simple photodetectors that can be easily replaced or manufactured at low cost. The device is designed to achieve sufficient measurement accuracy for consumer use without requiring the high-end, expensive components found in professional equipment, making it suitable for single-use or limited-life applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If professional calibration systems are implemented, then measurement reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The device includes pre-stored reference data and calibration information in its memory that corresponds to specific test types. When a test is performed, the microcontroller automatically retrieves and applies the appropriate calibration parameters, eliminating the need for manual calibration procedures or complex real-time calibration systems while ensuring measurement reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs automatic self-calibration and quality control by comparing measured values against stored reference data. The microcontroller automatically adjusts measurement parameters and compensates for variations based on pre-programmed calibration algorithms, allowing the device to maintain reliability without requiring external calibration equipment or complex manual intervention.

Inventive Principle:
Principle #25Self-service

3Device complexity

If simple optical systems are used to reduce cost, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The device replaces complex mechanical scanning systems with a stationary optical arrangement using an array of photodetectors that simultaneously detect multiple test lines. This substitution eliminates moving parts and mechanical complexity while maintaining measurement precision through parallel detection, achieving both simplicity and accuracy.

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

Solution Approach 2:

Instead of using a single photodetector that scans across the test strip in one dimension, the invention employs a photodetector array that detects multiple positions simultaneously across the test strip width. This dimensional expansion from point-by-point scanning to parallel array detection maintains measurement precision while dramatically reducing device complexity and measurement time.

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

4Measurement precision

If batch-specific calibration data are required, then measurement accuracy is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidease of operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The device automatically identifies the test type and retrieves the corresponding batch-specific calibration data from its stored reference information. The microcontroller seamlessly matches the inserted test strip with the appropriate calibration parameters without requiring the user to manually select or input calibration data, maintaining measurement accuracy while preserving ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates automatic feedback mechanisms where the microcontroller detects which type of test strip is inserted and automatically loads the corresponding calibration parameters from memory. This closed-loop system ensures that the correct batch-specific calibration data are applied without user intervention, combining measurement precision with user-friendly operation.

Inventive Principle:
Principle #23Feedback

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 device achieves high measuring accuracy and resolution, similar to professional readers, is cost-effective, and can be used for various tests, eliminating the need for batch-dependent calibration, providing clear and reliable results for end-users.

Implementation Method 1

A simple, camera-based measuring device with a pinhole or slit diaphragm for imaging

Methodology Applied
Scientific EffectOptical projection through pinhole/slit diaphragm: Lens

Implementation Method 2

using a CCD line and microcontroller, which is inexpensive, intuitive to use, and capable of evaluating multiple test lines

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP3036531B1Device for digitally reading rapid tests
Publication Date: 2023.06.07 BIOSYNEX TECHNOLOGIES GMBH
  • EP3036531B1 patent drawingFigure 1
  • EP3036531B1 patent drawingFigure 2
  • EP3036531B1 patent drawingFigure 3

AI summary

The invention relates to a device for the photometric quantization of lateral-flow rapid tests using camera imaging. The core concept of the invention is an assembly comprising a pinhole with a slot-type aperture integrated into the main body of the housing, in which assembly the imaging is optimised with respect to diffraction, image scale and integration behaviour and the lighting elements and all components are arranged in a housing that is cost-effective to produce, thus permitting a sufficiently accurate quantization of conventional LFA rapid tests for the test user. The device can transmit test-related data via a transponder in an automatic, contactless manner with the aid of electromagnetic waves (RFID) and is therefore suitable for various tests and for the quantization of LFAs.