Diamond Gate pH Sensor for Harsh Environment Stability

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Solution Overview

Problem

Existing pH and ion sensors face issues such as leakage and time degradation of internal liquids, contamination, and instability in high-temperature, high-pressure environments, particularly when handling bio-related materials or in strong acid/alkaline conditions.

Innovation Solution

A pH sensor and ion sensor design incorporating a reference electrode with a p-channel field effect transistor (FET) featuring a diamond surface with hydrogen ion insensitive terminals and a working electrode, which includes a glass electrode or p-type silicon semiconductor, allowing for accurate measurements without internal liquids and enhanced stability in severe environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a glass electrode type pH sensor with internal liquid and ceramic liquid junction is used, then pH measurement is enabled, but internal liquid leakage and contamination of the liquid to be measured occur

Engineering Contradiction:

ImprovepH measurement capabilityVSAvoidinternal liquid leakage and contamination

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and eliminates the internal liquid component from the reference electrode structure. By using a solid-state reference electrode without internal liquid, the source of leakage and contamination is removed while maintaining pH measurement functionality through alternative reference potential generation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical/liquid-based reference electrode system with a solid-state electronic system. The solid-state reference electrode substitutes the liquid-filled reference electrode, eliminating the need for liquid containment and junctions while providing stable reference potential.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If internal liquid is used in the reference electrode, then reference potential is provided, but moisture vaporization and crystallization occur under high-temperature conditions

Engineering Contradiction:

Improvereference potential stabilityVSAvoidhigh-temperature stability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The invention changes the physical state parameter of the reference electrode from liquid to solid. This parameter change enables the reference electrode to withstand high temperatures without vaporization or crystallization, while maintaining stable reference potential through the solid-state structure.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a self-assembled monolayer (SAM) is used for ion sensitive parts, then ion sensitivity is achieved, but physical and chemical instability occurs in high-temperature and strong acid/alkaline environments

Engineering Contradiction:

Improveion sensitivityVSAvoidstability in severe environments

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention uses composite material structures for the sensor electrodes. The gate electrode combines diamond surface (for chemical inertness and stability) with functional coatings (for ion sensitivity), creating a composite structure that maintains both sensitivity and stability in severe environments like high temperature and strong acid/alkaline conditions.

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If protein is adsorbed to the self-assembled monolayer in bioprocess, then bio-material handling is enabled, but accurate measurement becomes difficult

Engineering Contradiction:

Improvebioprocess compatibilityVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention creates an inert surface environment using diamond surface with specific termination (hydrogen or fluorine terminated). This inert surface prevents protein adsorption and contamination, maintaining measurement accuracy in bioprocesses while remaining compatible with bio-material handling.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 solution prevents leakage and time degradation of internal liquids, enables accurate pH and ion concentration measurements in harsh conditions, and is resistant to contamination, making it suitable for bioprocesses and chemical synthesis plants.

Implementation Method 1

a reference electrode including a p-channel field effect transistor (FET) whose gate includes a diamond surface having a hydrogen ion insensitive terminal

Methodology Applied

Scientific EffectHydrogen ion insensitive terminal:

Data Source

PatentUS9267913B2PH sensor, pH measurement method, ion sensor, and ion concentration measurement method

Publication Date: 2016.02.23 YOKOGAWA ELECTRIC CORP

AI summary

A pH sensor may include a reference electrode including a p-channel field effect transistor (FET) whose gate includes a diamond surface having a hydrogen ion insensitive terminal, and a working electrode.