Dielectric Sensor Gas Desorption Without Heater

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Solution Overview

Problem

Existing gas detection methods face challenges in miniaturizing gas detection elements while maintaining sensitivity, especially when detecting multiple gases, as they require heating members like heaters to desorb adsorbed gases efficiently.

Innovation Solution

A method where a dielectric sensor is heated by applying a specific signal between electrodes, without a separate heating member, to quickly and effectively desorb gases adsorbed on the gas adsorption film, allowing for rapid cooling and maintaining detection sensitivity even after repeated use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heater is provided independently from the gas detection element to desorb adsorbed gases, then gas desorption efficiency is improved, but the device size increases and miniaturization is restricted

Engineering Contradiction:
Improvegas desorption efficiencyVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the heating function into the dielectric sensor itself by applying voltage between electrodes. The dielectric sensor serves dual purposes: detecting gas mass changes and providing heating for desorption when voltage is applied, eliminating the need for separate heater structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dielectric sensor is designed to perform multiple functions: gas detection through mass change measurement and gas desorption through resistive heating. This multi-functionality reduces the overall device complexity and enables miniaturization by eliminating dedicated heater components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If the dielectric sensor is continuously vibrated at resonant frequency for detection, then detection sensitivity is maintained, but the adsorbed gas cannot be desorbed and sensitivity decreases over repeated measurements

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement durability
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The system alternates between detection mode (continuous vibration at resonant frequency) and desorption mode (voltage application for heating). This periodic switching allows the sensor to maintain high sensitivity during detection while periodically clearing adsorbed gases to prevent sensitivity degradation over time.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system periodically discards adsorbed gases through thermal desorption caused by voltage application, then recovers full detection sensitivity. This cycle of accumulation and removal maintains measurement accuracy over extended operation periods.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If a separate heater is used for gas desorption, then desorption effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvedesorption effectivenessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heating function is merged into the existing dielectric sensor structure by utilizing the electrodes already present for detection. Applying voltage between these electrodes generates resistive heating in the gas adsorption film, achieving effective desorption without adding separate heater components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dielectric sensor serves itself by using its own electrode structure to generate heating for desorption. The same electrodes used for detection also function as heating elements when voltage is applied, eliminating the need for external heating infrastructure.

Inventive Principle:
Principle #25Self-service

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 enables efficient gas desorption without a heater, allowing for miniaturization of gas detection elements and improved measurement efficiency by quickly regenerating the gas adsorption film for subsequent detections.

Implementation Method 1

the dielectric sensor is vibrated at a constant frequency (resonant frequency) by applying a voltage to a fine dielectric sensor (piezoelectric sensor)

Methodology Applied
Scientific EffectResonant vibration: Resonance

Implementation Method 2

a sensor using a mass microbalance method, the dielectric sensor is vibrated at a constant frequency (resonant frequency) by applying a voltage to a fine dielectric sensor (piezoelectric sensor)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

heating the dielectric sensor by applying a specific signal between electrodes

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP3605056B1Gas detection method, gas detection system, and gas desorption method
Publication Date: 2021.04.21 FUJIFILM CORP
  • EP3605056B1 patent drawingFigure 1~2A
  • EP3605056B1 patent drawingFigure 2B~2C
  • EP3605056B1 patent drawingFigure 2D~2E

AI summary

A gas detection method using a gas detection element obtained by laminating a fixed support, a first electrode 2, a dielectric sensor 3, a second electrode 4, and a gas adsorption film 5, in this order, the method including: a step of applying a first signal resonantly driving the dielectric sensor 3 between electrodes of the first electrode 1 and the second electrode 3, and detecting gas adsorbed on the gas adsorption film based on a change of a resonant frequency of the dielectric sensor; and a step of heating the dielectric sensor 3 by applying a second signal between the electrodes after the detection of gas and desorbing gas adsorbed in the gas adsorption film, a gas detection system capable of performing the method, and a gas desorption method appropriate for applying this gas detection method.