Insulated Rotary Plasma Electrode Structure Without Conductive Brushes
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Solution Overview
Problem
Existing plasma processing apparatuses face a risk of electrical contact and associated hazards due to the rotation of an electrically charged casing, which requires conductive bearings or brushes for rotation.
Innovation Solution
A plasma processing apparatus design that eliminates the need for electrically conductive bearings or brushes by using a rotary cylindrical portion made of an insulating material, which surrounds the outer electrode and is rotatable relative to it, thereby reducing the risk of electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically conductive casing is used for plasma processing, then plasma can be effectively generated and applied, but there is a risk of electrical contact and associated hazards during rotation
Solution Approach 1:
An insulating pipe made of electrically insulating material is introduced as an intermediary component between the electrically conductive inner electrode and the outer electrode/casing. This intermediary prevents direct electrical contact while allowing the plasma processing function to continue, thereby eliminating the electrical contact hazard associated with rotating conductive casings.
Solution Approach 2:
The electrical conductivity function is extracted from the rotating casing and assigned solely to the inner electrode. The outer rotating casing is converted to a non-conductive insulating pipe, separating the electrical function from the mechanical rotation function and eliminating the safety hazard of rotating conductive parts.
2Reliability
If an insulating material is used for the rotary cylindrical portion, then the risk of electrical contact is reduced, but the structural complexity increases due to additional insulating components
Solution Approach 1:
The insulating pipe serves multiple functions simultaneously: it provides electrical insulation between the inner electrode and outer electrode, acts as a structural support for the electrode assembly, and functions as part of the rotating mechanism. By merging these functions into a single component, the overall structural complexity is minimized while maintaining electrical safety.
Solution Approach 2:
The insulating pipe is designed as a multi-functional component that combines electrical insulation, mechanical support, and rotational functionality. This universal design eliminates the need for separate insulating bearings or additional conductive shielding components, thereby reducing structural complexity while ensuring electrical safety.
3Ease of operation
If a conductive bearing or electric brush is used to rotate the electrically charged casing, then the casing can rotate smoothly, but the device becomes more expensive and complex
Solution Approach 1:
The electrical contact function is extracted from the rotation mechanism. Instead of using conductive bearings or electric brushes that would require complex electrical connections during rotation, the outer casing is made insulating, allowing it to rotate freely without any electrical connection mechanism, thereby eliminating the complex bearing system.
Solution Approach 2:
The insulating pipe structure itself provides the rotation capability without requiring external conductive bearings or brushes. The design uses the insulating property of the material to enable self-contained rotation, eliminating the need for additional complex rotational support mechanisms.
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 provides a safer and more cost-effective plasma processing apparatus by reducing the risk of electrical contact and eliminating the need for conductive components, while maintaining the ability to apply plasma conforming to the shape of a workpiece.
Implementation Method 1
an insulating pipe disposed between the inner electrode and the outer electrode and between the electrode holder and the outer electrode
Implementation Method 2
a rotary cylindrical portion made of an insulating material and formed in a cylindrical shape surrounding the outer electrode, the rotary cylindrical portion being rotatable relative to the outer electrode about a central axis of the inner electrode
Implementation Method 3
electrical discharge occurs between the electrode and the casing upon application of a voltage to the electrode
Data Source
Figure 1
Figure 2
AI summary
A plasma processing apparatus (1) includes: an inner electrode (100); an electrode holder (200); an outer electrode (400) formed in a cylindrical shape, the outer electrode surrounding the inner electrode and the electrode holder; an insulating pipe (500) disposed between the inner electrode and the outer electrode and between the electrode holder and the outer electrode, the insulating pipe surrounding the inner electrode and the electrode holder; a rotary cylindrical portion (600) made of an insulating material and formed in a cylindrical shape surrounding the outer electrode, the rotary cylindrical portion being rotatable relative to the outer electrode about a central axis (AX) of the inner electrode; and a drive mechanism (700) that rotates the rotary cylindrical portion.