Laboratory Cuvette Form Correction via Indirect Liquid-Level Measurement

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Solution Overview

Problem

Existing methods for determining cuvette form correction values in laboratory analysis are technically challenging and require direct camera access through the cuvette opening, limiting their applicability and increasing production waste and costs due to stringent dimensional accuracy requirements.

Innovation Solution

An indirect method using a level determination camera to measure the liquid reagent volume and calculate the cuvette's horizontal inner width, allowing for the determination of a form correction value without requiring a camera to view the cuvette interior, and incorporating a meniscus interpretation module to account for surface tension effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct camera measurement through cuvette opening is used to determine inner diameter, then measurement precision is improved, but device complexity increases and applicability is limited

Engineering Contradiction:
Improvecuvette inner diameter measurementVSAvoidcamera system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary approach by using the liquid reagent level as a mediator to indirectly determine the cuvette inner diameter. Instead of directly measuring the cuvette opening with a camera, the system measures the liquid level height, which is easier to access and less complex, while still providing the necessary dimensional information through calculation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/optical measurement system (camera looking through cuvette opening) with a computational approach based on liquid level measurement. By substituting direct physical measurement with calculated determination from liquid level data, the system achieves the same measurement goal with simpler equipment and broader applicability.

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

2Measurement precision

If stringent dimensional accuracy requirements are imposed on cuvettes, then measurement precision is improved, but production waste increases

Engineering Contradiction:
Improvephotometric measurement accuracyVSAvoidcuvette production waste
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent changes the approach from controlling cuvette manufacturing parameters (inner diameter) to measuring liquid level parameters. By shifting the measurement focus from the cuvette's physical dimensions to the liquid reagent level, the system allows greater manufacturing tolerance while maintaining measurement accuracy through computational correction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by calculating a form correction value based on the measured liquid level and using this correction to adjust subsequent photometric measurements. This feedback mechanism compensates for cuvette dimensional variations, allowing production to accept larger tolerances without sacrificing measurement precision.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If camera is positioned to view cuvette interior through opening, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecuvette inner diameter determinationVSAvoidcuvette measurement operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent inverts the measurement approach by measuring from the outside through the liquid level rather than looking inside through the opening. This inversion makes the measurement operation simpler and more versatile, as it works with the liquid reagent already present in the cuvette without requiring special positioning or access to the cuvette interior.

Inventive Principle:
Principle #13The other way round (Inversion)

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

Accurately determines the cuvette form correction value, reducing production waste and costs while enhancing the accuracy of analyte concentration measurements in photometric analysis.

Implementation Method 1

The liquid reagent level of the liquid reagent in the laboratory analysis cuvette is determined optically by a level determination camera

Methodology Applied
Scientific EffectOptical measurement: Absorption (EM radiation)

Implementation Method 2

incorporating a meniscus interpretation module to account for surface tension effects

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

the measured transmission or absorption is substantially proportional to the concentration of the analyte in question

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP4433773B1Method for determining a cuvette form correction value
Publication Date: 2025.08.06 HACH LANGE HACH LANGE
  • EP4433773B1 patent drawingFigure 1~2
  • EP4433773B1 patent drawingFigure 3
  • EP4433773B1 patent drawingFigure 4

AI summary

The invention refers to a method for determining a cuvette form correction value (F) for a laboratory analysis cuvette (10) filled with a liquid reagent (60) and having a transparent cuvette body (12) comprising a vertical wall (14) and a bottom wall (13), comprising the method steps: Determining the liquid reagent volume (V) of the liquid reagent (60) filled into the laboratory analysis cuvette (10), optically determining the liquid reagent level (H) of the liquid reagent (60) in the laboratory analysis cuvette (10) by a level determination camera (24), calculating a horizontal inner width (D) of the laboratory analysis cuvette (10) from the determined liquid reagent volume (V) and the determined liquid reagent level (H) by an electronic control (26), and calculation of the form correction value (F) from the calculated horizontal inner width (D) and a reference inner width (D') of the laboratory analysis cuvette (10) by the electronic control (26).