Handheld Aqueous Solution Analyzer with Self-Calibrating Reflectance

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Solution Overview

Problem

Conventional test elements for analyzing aqueous solutions, such as pool or spa water, are inconvenient and prone to inaccurate results due to the need for manual calibration and are expensive to manufacture, while existing blood glucose test strips face interference from blood color and hematocrit levels.

Innovation Solution

A portable, hand-held electronic device with a self-calibrating capability that uses a test element with chemically treated pads to determine chemical characteristics of aqueous solutions by analyzing reflectance values across multiple wavelength ranges, minimizing radiation reflection and transmittance, and automatically processing signals to provide accurate readings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional test elements use visual color comparison with color charts, then the device complexity is low, but the measurement precision deteriorates due to subjective interpretation and ambient light interference

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

Solution Approach 1:

The patent replaces the manual visual comparison method with an automated electronic reflectance measurement system. A radiation source illuminates the test element pads, and a photodetector measures the reflected light intensity at specific wavelengths. The microprocessor calculates the analyte concentration based on the reflectance ratio, eliminating subjective visual interpretation and ambient light interference while maintaining relatively simple device construction.

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

Solution Approach 2:

The patent introduces an optical intermediary system consisting of a radiation source, optical path, and photodetector to mediate between the test element and the measurement system. This intermediary converts the chemical color change into a quantifiable electrical signal through optical reflectance measurement, enabling precise automated analysis while keeping the overall device structure manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If blood glucose test strips are used to measure reflectance, then the measurement capability is improved, but the reliability deteriorates due to interference from blood color and hematocrit levels

Engineering Contradiction:
Improvemeasurement precisionVSAvoidreliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameter from absolute reflectance to reflectance ratio by measuring at multiple wavelengths. The microprocessor calculates the ratio of reflectance at different wavelengths, which compensates for the effects of blood color and hematocrit variations. This parameter transformation maintains measurement precision while significantly improving reliability by eliminating interfering factors.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If manual calibration steps are required for test devices, then the manufacturing cost is reduced, but the ease of operation deteriorates and measurement reliability decreases

Engineering Contradiction:
Improveease of manufactureVSAvoidease of operation
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent implements self-calibration functionality where the device automatically performs calibration without requiring manual user intervention. The microprocessor controls the measurement sequence, automatically compares readings against stored reference values, and adjusts calibration parameters as needed. This eliminates the need for users to perform manual calibration steps while keeping manufacturing costs relatively low.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback mechanisms where the device measures reflectance, compares it against reference standards, and automatically adjusts calibration parameters based on the difference. The microprocessor uses this feedback loop to maintain accurate measurements without requiring manual calibration, improving ease of operation while maintaining manufacturing simplicity.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If protective shrouds with precision mechanical components are used to guide test strips, then the measurement precision is improved, but the device complexity increases and reliability decreases due to mechanical failure risks

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

Solution Approach 1:

The patent replaces complex mechanical test strip guidance systems with a simplified optical measurement chamber. The device uses a fixed radiation source and photodetector arrangement with a simple test element receptacle that requires no precision mechanical components. Test elements are held in place through simple mechanical retention, eliminating camming members, fingers, and grooves while maintaining measurement precision through optimized optical geometry.

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

The device provides accurate and convenient analysis of aqueous solutions by compensating for testing variables and ambient light interference, reducing the need for manual calibration and enhancing the reliability of measurements.

Implementation Method 1

a radiation source is configured to emit radiation toward the test element pads, and a radiation detection circuit is configured to measure reflected radiation from the test element pads

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2069776B1Method and apparatus for analyzing solutions
Publication Date: 2017.12.13 HACH
  • EP2069776B1 patent drawingFigure 1A~1B
  • EP2069776B1 patent drawingFigure 2
  • EP2069776B1 patent drawingFigure 3

AI summary

An apparatus and method of analyzing an aqueous solution, as may be implemented with a hand-held portable electronic device (10). A test pad (32) responsive in color to a characteristic of an aqueous solution is interrogated by the device by measuring, in a plurality of wavelength ranges, intensity values of a test light as reflected off of the test strip. The intensity values may be expressed as values relative to intensities reflected off of white and black calibration surfaces. A relationship among the intensity values for the various wavelength ranges is developed through an algorithm that provides a ratio value that is responsive to the characteristic of the aqueous solution and that is non-responsive to absolute intensity values of the reflected light. The test pad may be supported on an opaque and non-reflective substrate (28) that cooperates with an opaque edge portion (14E) of a test element placement member (14B) and associated side walls (14W) of the device to minimize the impingement of ambient light onto the test pad during interrogation.