Solid-State Ion-Sensitive Film Reference Electrode for Rapid Connection

Solution Overview

Problem

Existing electrochemical ion sensors with internal solutions face issues such as performance degradation due to solvent evaporation, high production costs, and prolonged time to establish electrical connection with the measured liquid, which complicates automated production and measurement efficiency.

Innovation Solution

A reference electrode design featuring a substrate with a metal electrode portion and an ion-sensitive film containing an inorganic salt and organic substance, where the electrode portion and inorganic salt share the same anion, and the electrode shape is optimized to facilitate rapid diffusion of the liquid, ensuring a maximum shortest distance of about 0.3 mm or less from any point to the perimeter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reference electrode with an internal solution is used, then stable potential can be maintained, but the time to establish electrical connection with the measured liquid becomes long

Engineering Contradiction:

Improvepotential stabilityVSAvoidelectrical connection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the internal solution component from the reference electrode structure. By replacing the liquid-filled internal solution reservoir with a solid-state ion-sensitive film containing inorganic salt and organic substance, the patent removes the source of the delay while maintaining the electrode's potential stability function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the physical state parameter of the internal solution from liquid to solid-state composite material. The ion-sensitive film uses inorganic salt in a solid or gel state combined with organic substance, fundamentally altering the state of matter to eliminate evaporation issues and reduce connection time while preserving electrochemical functionality.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the internal solution volume is reduced, then device size can be minimized, but performance degradation occurs due to solvent evaporation

Engineering Contradiction:

Improveinternal solution volumeVSAvoidelectrode performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The invention changes the physical state parameter of the internal solution from liquid to solid-state composite material. The ion-sensitive film uses inorganic salt in a solid or gel state combined with organic substance, fundamentally altering the state of matter to eliminate evaporation issues and reduce connection time while preserving electrochemical functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The solid-state ion-sensitive film structure eliminates the need for large volumes of liquid internal solution that would otherwise require frequent replacement due to evaporation. The solid-state design is inherently more stable and does not suffer from the same degradation issues.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If a conventional reference electrode structure is used, then stable potential can be achieved, but production complexity and costs increase

Engineering Contradiction:

Improvepotential stabilityVSAvoidproduction process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the internal solution component from the reference electrode structure. By replacing the liquid-filled internal solution reservoir with a solid-state ion-sensitive film containing inorganic salt and organic substance, the patent removes the source of the delay while maintaining the electrode's potential stability function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by creating a focused ion-sensitive film layer with specific composition (inorganic salt and organic substance in 1:1 to 1:10 weight ratio) at the electrode surface, rather than requiring a bulk liquid internal solution. This localized functional layer simplifies the overall structure and manufacturing process.

Inventive Principle:

Principle #3Local quality

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 design significantly reduces the time to establish electrical connection, stabilizes potential quickly, and minimizes potential drift, enabling efficient and cost-effective electrochemical measurements suitable for applications like sweat analysis and environmental monitoring.

Implementation Method 1

the electrode shape is optimized to facilitate rapid diffusion of the liquid

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

an ion-sensitive film covering the electrode portion and including an inorganic salt and an organic substance

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS12385871B2Reference electrode for electrochemical measurement

Publication Date: 2025.08.12 MURATA MFG CO LTD

AI summary

A reference electrode for electrochemical measurement includes a substrate, an electrode portion on the substrate, and an ion-sensitive film covering the electrode portion and including an inorganic salt and an organic substance. The electrode portion and the inorganic salt include an anion of the same element. In a top view of the electrode portion, the maximum shortest distance from any point in the electrode portion to the outer perimeter of the electrode portion is about 0.3 mm or less.