Piezoelectric Diaphragm Mass Sensor for Accurate Pipetting

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Solution Overview

Problem

Existing automatic analysis devices face challenges in accurately measuring and pipetting small liquid masses due to vibration disturbances and the difficulty in ensuring reliable analysis results without the practicality of large anti-vibration tables.

Innovation Solution

An automatic analysis device equipped with a mass sensor that includes a piezoelectric element and diaphragm configuration to measure the mass of liquids in reaction containers, using flexural vibration to detect and correct deviations in pipetting amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an anti-vibration table is installed to reduce vibration disturbance, then measurement precision is improved, but device complexity and size increase

Engineering Contradiction:
Improvemass measurement precisionVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the vibration isolation function from a separate anti-vibration table and integrates it into the mass sensor itself through the diaphragm structure. The diaphragm acts as a natural vibration isolator, eliminating the need for external anti-vibration equipment while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mass sensor is nested within the compact reaction container assembly, with the diaphragm integrated into the container structure. This nested design allows the vibration isolation function to be embedded within the existing device architecture without adding external components.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If the pipetting mechanism is made more precise to ensure accurate liquid dispensing, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvepipetting amount precisionVSAvoidpipetting mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mass sensor provides real-time feedback on the actual mass of liquid dispensed into the reaction container. This feedback allows the system to detect and correct pipetting errors, ensuring accurate liquid dispensing without requiring an overly complex pipetting mechanism with multiple adjustment components.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical precision control in the pipetting mechanism with a sensor-based detection and correction system. Instead of relying solely on mechanical precision, the system uses mass measurement feedback to ensure accurate dispensing, simplifying the mechanical design.

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

Ensures accurate pipetting of specimens and samples in predetermined amounts, enhancing the reliability of analysis results by detecting and correcting deviations in pipetting operations.

Implementation Method 1

a piezoelectric element joined to the diaphragm

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4632335A1Automatic analysis device and mass sensor
Publication Date: 2025.10.15 HITACHI HIGH TECH CORP
  • EP4632335A1 patent drawingFigure 1
  • EP4632335A1 patent drawingFigure 2~3
  • EP4632335A1 patent drawingFigure 4

AI summary

The present disclosure ensures reliability of analysis results by accurately pipetting a specimen and a sample in a predetermined pipetting amount. An automatic analysis device includes: a reagent holder configured to hold a reagent container that contains a reagent; a specimen holder configured to hold a specimen container that contains a specimen; a pipetting mechanism configured to pipette the reagent and the specimen into a reaction container; and a mass sensor configured to measure a mass of the reaction container. The mass sensor includes: a fixing portion; a diaphragm at least a part of which is fixed by the fixing portion; a piezoelectric element joined to the diaphragm; and a container placement portion that is supported on the diaphragm and is configured to hold the reaction container into which a liquid to be measured is discharged.