Ion Sensor Insulator Resolves FAIMS Discharge Contradiction

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Solution Overview

Problem

Existing FAIMS systems suffer from low detectivity due to the gap between the ion filter and the ion sensing electrode, which leads to ion dispersion and increased ion loss, and shortening this gap can result in unwanted electric discharge.

Innovation Solution

Incorporating a solid insulator between the ion filter and the ion sensing electrode to reduce ion loss while preventing electric discharge, and using an asymmetric electric field waveform to selectively direct ions to the sensing electrode, thereby enhancing detectivity and structural stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the distance between the ion filter and the ion sensing electrode is shortened, then ion loss is reduced and detectivity is improved, but unwanted electric discharge occurs between the ion filter and the ion sensing electrode

Engineering Contradiction:
ImprovedetectivityVSAvoidelectric discharge
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a third electrode positioned between the ion filter and the ion sensing electrode. This intermediate electrode acts as a mediator that prevents direct electric discharge between the ion filter and sensing electrode while maintaining a short effective distance for ion detection, thus resolving the contradiction between reducing ion loss and preventing electric discharge.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a gap of centimeter order exists between the ion filter and the ion sensing electrode, then electric discharge is prevented, but ion spatial dispersion increases and ion loss increases

Engineering Contradiction:
Improveelectric discharge preventionVSAvoidion loss
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The third electrode serves as an intermediary structure that enables the system to maintain a physically small gap distance while effectively preventing electric discharge. The intermediate electrode divides the gap into two smaller regions, each with lower electric field strength, thereby preventing discharge while maintaining short ion travel distance and reducing ion loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the distance between the ion filter and the ion sensing electrode is shortened, then ion spatial dispersion is reduced, but the structure becomes more prone to electric discharge

Engineering Contradiction:
Improveion spatial distributionVSAvoidelectric discharge resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The third electrode maintains stable ion spatial distribution by keeping the physical gap short, while simultaneously ensuring discharge resistance by acting as an intermediate barrier that reduces the electric field strength in each sub-gap region, thus maintaining both ion spatial stability and discharge resistance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves high detectivity by minimizing ion loss and preventing electric discharge, while maintaining a close proximity of the ion filter and sensing electrode, and allows for precise detection of various ions through the asymmetric electric field configuration.

Implementation Method 1

ionized chemical substances are sorted according to a difference in the degree of mobility as the ionized chemical substances flow through the ion filter

Methodology Applied
Scientific EffectIon mobility spectrometry:

Implementation Method 2

ions tend to spatially disperse due to dispersion and the Coulomb repulsive force

Methodology Applied
Scientific EffectCoulomb repulsive force: Coulomb's Law

Implementation Method 3

a solid insulator that electrically insulates the ion sensing electrode from the first electrode and the second electrode

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

As ionized chemical substances that have passed through the ion filter collide with an ion sensing electrode, and electric current is generated at the ion sensing electrode

Methodology Applied
Scientific EffectIon collision current generation:

Data Source

PatentEP3508844B1Ion sensor, ion sensor manufacturing method, and field asymmetric ion mobility spectrometry system
Publication Date: 2023.05.24 RICOH CO LTD
  • EP3508844B1 patent drawingFigure 1
  • EP3508844B1 patent drawingFigure 2
  • EP3508844B1 patent drawingFigure 3

AI summary

An ion sensor, an ion sensor manufacturing method, and a field asymmetric ion mobility spectrometry (FAIMS) system. The ion sensor includes an ion filter (110) including a first electrode (111, 411, 480, 680) and a second electrode (112, 412, 480) facing each other, an ion sensing electrode (120, 220, 320, 460, 560, 680) with which an ion that has passed through the ion filter (110) collides, and an insulator (130, 470, 660, 670) configured to electrically insulate the ion sensing electrode (120, 220, 320, 460, 560, 680) from the first electrode (111, 411, 480, 680) and the second electrode (112, 412, 480). The method includes forming a first slit (481) on an active layer (480, 680) of an at least one SOI substrate (450, 470, 480, 550, 650), dividing the active layer (480, 680) into two, and forming a second slit (461) through the base layer (460, 463, 560, 660).