Automated Analyzer Waveform Processing for Air Bubble Detection

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Solution Overview

Problem

Existing automatic analyzers face challenges in accurately determining analysis errors due to air bubbles or scratches in reaction vessels, as techniques like PTL 1 require reference light measurement waveforms and PTL 2's standard deviation calculations are insufficient for handling reagent dispensing changes.

Innovation Solution

An automatic analyzer with a reaction disk, light detection system, and spectrophotometer data processing unit that samples transmitted light waveform data to identify air bubble influences by calculating differences or derivatives, allowing accurate determination of air bubble impacts on analysis results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reference light measurement waveform is used to determine errors (PTL 1), then error detection capability is improved, but accuracy deteriorates when air bubbles or scratches are present during reference acquisition

Engineering Contradiction:
Improveerror detection capabilityVSAvoiderror determination accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent creates a virtual reference waveform by copying and processing multiple actual measurement waveforms. Instead of using a single reference waveform that may be contaminated by air bubbles or scratches, the system acquires multiple measurement waveforms under identical conditions and synthesizes a reference waveform from them, eliminating the problem of reference contamination.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system performs preliminary acquisition of multiple measurement waveforms before determining the final error. By collecting multiple waveforms in advance and processing them to create a robust reference, the system prepares a cleaner baseline for error detection, avoiding the issue of using a potentially contaminated single reference waveform.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If standard deviation is calculated for each photometric point (PTL 2), then measurement variability is analyzed, but reagent dispensing changes cause remarkable absorbance changes that prevent appropriate absorbance determination

Engineering Contradiction:
Improvemeasurement variability analysisVSAvoidabsorbance determination accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts only the portions of waveforms that are truly representative of stable measurement conditions. By identifying and isolating stable sections from multiple waveforms, the system removes the influence of reagent dispensing changes and other transient variations, keeping only the reliable portions for reference waveform creation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system segments multiple measurement waveforms into stable and unstable portions, then selectively processes only the stable segments. This segmentation allows the system to exclude portions affected by reagent dispensing changes while incorporating reliable measurement data from stable periods.

Inventive Principle:
Principle #1Segmentation

3Difficulty of detecting and measuring

If transmitted light amount waveform data is analyzed directly, then air bubble detection is attempted, but accurate identification of air bubble influenced sampling sections is difficult

Engineering Contradiction:
Improveair bubble detection capabilityVSAvoidsampling section identification accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

Instead of trying to directly identify air bubble sections from the original waveform, the patent inverts the approach by creating a reference waveform first and then comparing the original waveform against this reference. The deviations from the reference waveform reveal the air bubble influenced sections, making detection more accurate.

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

Solution Approach 2:

The system uses the reference waveform as a feedback baseline to continuously evaluate and identify abnormal sections in measurement waveforms. By comparing actual measurements against the established reference and analyzing deviations, the system accurately identifies which sampling sections are influenced by air bubbles.

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

This approach enhances analysis accuracy and reliability by identifying and mitigating the effects of air bubbles, improving the overall performance of the analyzer.

Implementation Method 1

the spectrophotometer includes a transmitted light measuring instrument that measures an amount of transmitted light of light from the light source passing through the reaction vessel

Methodology Applied
Scientific EffectLight transmission measurement: Absorption (EM radiation)

Implementation Method 2

determines an influence of an air bubble in a reaction liquid contained in the first reaction vessel based on a change over time in the transmitted light amount difference waveform data or the transmitted light amount derivative waveform data

Methodology Applied
Scientific EffectLight scattering by air bubbles: Scattering

Data Source

PatentEP4685491A1Automated analysis device and sample analysis method
Publication Date: 2026.01.28 HITACHI HIGH TECH CORP
  • EP4685491A1 patent drawingFigure 1~2
  • EP4685491A1 patent drawingFigure 3
  • EP4685491A1 patent drawingFigure 4~5

AI summary

A waveform acquisition unit 123 samples the amount of transmitted light measured by a transmitted light measuring instrument 202 while a reaction vessel 106 passes a light measurement point as a result of the rotation of a reaction disk 103, and acquires the amount of transmitted light as transmitted light amount waveform data, and a data processing unit 124 calculates a difference or derivative of the transmitted light amount waveform data of the first reaction vessel to acquire transmitted light amount difference waveform data or transmitted light amount differentiation waveform data, and determines the influence of air bubbles in a reaction liquid stored in the first reaction vessel on the basis of a change over time in the transmitted light amount difference waveform data or the transmitted light amount differentiation waveform data for each photometric sampling when the first reaction vessel passes the light measurement point. As a result, the analysis accuracy and reliability of the automated analysis are improved.