Tungsten Oxide Hydrogen Sensor Layout for Leak Spot Detection

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Solution Overview

Problem

Conventional hydrogen sensors, such as contact combustion and semiconductor types, are limited to detecting hydrogen gas in a narrow range and cannot accurately identify leakage spots, posing safety risks due to the need for heating and narrow detection capabilities.

Innovation Solution

A hydrogen sensor utilizing a substrate with a sensitive film containing a catalyst and tungsten oxide, which detects changes in electrical resistance through a network of first and second sensor electrodes connected to bus electrodes, allowing wide-range detection and identification of leakage spots without heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional contact combustion or semiconductor methods are used for hydrogen detection, then hydrogen gas can be detected, but heating is required which creates explosion risks and limits detection to a narrow range

Engineering Contradiction:
ImprovesafetyVSAvoidheating requirement
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent extracts and eliminates the heating function from the hydrogen detection system. By using tungsten oxide semiconductor material that changes electrical characteristics upon hydrogen adsorption at ambient temperature, the harmful heating element is completely removed while preserving the detection function, thus resolving the safety contradiction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the thermal-based detection mechanism (contact combustion) with an electrical-based mechanism (semiconductor resistance change). The heating system is substituted with an electrical measurement system that detects hydrogen through changes in electrical resistance of the tungsten oxide film, eliminating explosion risks while maintaining detection capability.

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

2Area of stationary object

If a single detection point is used, then the sensor structure is simple, but the detection range is narrow and leakage spots cannot be specified

Engineering Contradiction:
Improvedetection rangeVSAvoidsensor structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the detection area into multiple segments by arranging several sensor electrodes (first sensor electrodes and second sensor electrodes) in an alternating pattern across the substrate. Each electrode pair acts as an independent detection segment, allowing the system to cover a wide area while identifying specific leakage locations through the pattern of activated segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-point detection approach to a distributed two-dimensional detection network. By arranging multiple sensor electrodes across the substrate surface in alternating patterns, the system creates a spatial map of hydrogen concentration, enabling both wide-area coverage and precise location identification simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 sensor can detect hydrogen gas over a wide area at low cost and accurately identify leakage spots, suitable for small devices and large facilities, enhancing safety by eliminating the need for heating and improving detection accuracy.

Implementation Method 1

a sensitive film that is disposed on a first surface of the substrate, and that includes a catalyst dissociating hydrogen molecules

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

a gas-chromic type hydrogen sensor includes a metal oxide such as tungsten trioxide in which a color changes due to adsorption of hydrogen

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

the metal oxide such as tungsten trioxide also changes the electrical characteristics by the adsorption of hydrogen

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4722703A1Hydrogen sensor, hydrogen detection system, and sheet for hydrogen sensors
Publication Date: 2026.04.08 DAI NIPPON PRINTING CO LTD
  • EP4722703A1 patent drawingFigure 1
  • EP4722703A1 patent drawingFigure 2
  • EP4722703A1 patent drawingFigure 3

AI summary

The present disclosure provides a hydrogen sensor including: a substrate, a sensitive film that is disposed on a first surface of the substrate, and that includes a catalyst dissociating hydrogen molecules, and tungsten oxide, a control unit that detects a change in electrical resistance, a first bus electrode and a second bus electrode disposed on the first surface of the substrate and connected to the control unit, a plurality of first sensor electrodes disposed in contact with the sensitive film on the first surface of the substrate and connected to the first bus electrode, and a plurality of second sensor electrodes disposed in contact with the sensitive film on the first surface of the substrate and connected to the second bus electrode, wherein the first sensor electrodes and the second sensor electrodes are alternately arranged at intervals in which a change in electrical resistance of the sensitive film can be detected.