Microplasma Jet Generator with VHF Inductive Coupling
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Solution Overview
Problem
Stable generation of high-density microplasma jets in microspaces at atmospheric pressure with low electric power is challenging, limiting high-resolution microanalysis in μTAS systems.
Innovation Solution
A microplasma jet generator driven by a VHF power supply with a flat meandering micro-antenna and a discharge tube, using inductive coupling to generate high-density plasma with low electric power, reducing the need for water-cooling and enabling compact, portable systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional direct-current arc discharge is used to generate plasma jets, then fine plasma jets with diameter of 2 mm or less can be generated, but electrodes are worn, reactive gas cannot be used, and workpieces are limited to conductors
Solution Approach 1:
The patent extracts and eliminates the electrodes from the plasma generation system, replacing them with an electrodeless RF induction coupling method. This allows plasma to be generated without physical contact, eliminating electrode wear while maintaining the capability to generate fine plasma jets with diameter of 2 mm or less.
Solution Approach 2:
The patent replaces the mechanical electrode-based arc discharge system with an electromagnetic field-based RF induction system. The mechanical contact between electrodes and plasma is substituted by non-contact electromagnetic induction, enabling the use of reactive gases and eliminating electrode degradation.
2Measurement precision
If high-density plasma is generated in a microspace, then high-resolution microanalysis can be performed, but it requires large electric power which complicates the system with water-cooling requirements
Solution Approach 1:
The patent changes the frequency parameter to VHF (very high frequency) range and optimizes the discharge tube dimensions to micro-scale. This parameter change enables efficient coupling of RF energy to the plasma, generating high-density plasma in a microspace with reduced power consumption that eliminates the need for water-cooling systems.
3Adaptability or versatility
If atmospheric pressure operation is used for plasma generation, then practical applications are enabled, but stable high-density plasma generation in microspace becomes difficult
Solution Approach 1:
The patent skips the problematic intermediate pressure range by operating at atmospheric pressure with optimized VHF frequency and micro-discharge tube dimensions. This configuration allows the system to rush through the challenge of atmospheric pressure operation by creating a resonant coupling condition that maintains plasma stability despite the higher pressure 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
Stable generation of high-density microplasma jets with low electric power consumption, suitable for μTAS systems, enabling efficient surface treatment and processing with reduced weight and gas consumption, and improved sensitivity in chemical microanalysis.
Implementation Method 1
a microplasma jet generator driven with a VHF power supply for generating an inductively coupled microplasma jet
Implementation Method 2
A plasma gas 104 is introduced into one end of the discharge tube 103 and a microplasma jet 105 is discharged from the other end
Data Source
AI summary
The present invention provides a microplasma jet generator capable of stably generating a microplasma jet in a microspace at atmospheric pressure with low electric power.The microplasma jet generator is driven with a VHF power supply to generate an inductively coupled microplasma jet and includes a substrate, a micro-antenna disposed on the substrate, and a discharge tube located close to the micro-antenna. The micro-antenna has a flat meandering shape with plural turns.