Hollow Cathode Arc Plasma Device Bipolar Pulsed Voltage

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Solution Overview

Problem

Existing hollow cathode arc discharge plasma devices face limitations in generating high-intensity and large-volume plasmas due to complex structures and requirements for maintaining electrical conductivity, especially when dealing with insulating materials, and struggle to maintain plasma stability at higher ambient pressures.

Innovation Solution

A device comprising two plasma-generating units with hollow cathodes and ring-shaped electrodes, connected by a pulse generator producing bipolar medium-frequency voltage, eliminating the need for a DC voltage source and utilizing magnetic coils to enhance plasma generation and stability, allowing for high-intensity and large-volume plasma creation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a longitudinal magnetic field is generated to bind higher-energy beam electrons, then plasma density is maintained at a distance from the substrate, but the build-up of high self-bias potential is prevented and the device structure becomes complex

Engineering Contradiction:
Improveplasma densityVSAvoidmagnetic field generating device
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent extracts the magnetic field generating device from the system, eliminating the need for complex magnet systems while maintaining plasma generation capability through the hollow cathode arc discharge mechanism alone

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hollow cathode structure itself generates the necessary plasma and electron acceleration without requiring external magnetic field generation, making the system self-sufficient and structurally simpler

Inventive Principle:
Principle #25Self-service

2Reliability

If a ring anode is arranged directly in front of the hollow cathode, then insulating layer deposition is avoided, but charge carrier density in the plasma is significantly reduced

Engineering Contradiction:
Improveelectrical conductivity maintenanceVSAvoidcharge carrier density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent transitions from a two-dimensional ring anode configuration to a three-dimensional hollow cathode structure with radial electron emission, enabling plasma generation throughout the hollow cathode volume and achieving high charge carrier density without insulating layer deposition issues

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

3Volume of stationary object

If two plasma-generating devices with DC voltage sources are arranged to create bipolar pulsed voltage, then large-volume plasma is generated, but the structure becomes technically demanding with many process parameters to regulate

Engineering Contradiction:
Improveplasma volumeVSAvoiddual plasma-generating devices with DC sources
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent employs periodic switching of a single DC voltage source between two hollow cathodes to generate bipolar pulsed voltage, achieving large-volume plasma through temporal alternation rather than simultaneous dual-device operation, thereby simplifying the overall structure

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent combines the functions of two separate plasma-generating devices with DC voltage sources into a single device with one DC voltage source that alternates between two hollow cathodes, reducing structural complexity while maintaining plasma volume

Inventive Principle:
Principle #5Merging (Combining)

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 enables the generation of stable, high-intensity plasmas with a large volume, even at higher ambient pressures, simplifying the device structure and reducing the complexity of process parameter regulation, while effectively supporting both conductive and insulating material vaporization.

Implementation Method 1

hollow cathode arc discharge sources

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Implementation Method 2

generating dense plasmas for vacuum processes

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 3

If a longitudinal magnetic field is generated by suitable magnetic field generating devices in such a way that some of its field lines lead from the hollow cathode to the anode, higher-energy beam electrons remain bound in the area of ​​the connecting field lines

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 4

a ring-shaped anode (a so-called ring anode) is arranged directly in front of the hollow cathode in order to generate the plasma that is effective for plasma activation solely through the beam electrons which penetrate the opening of the ring anode

Methodology Applied
Scientific EffectElectron beam: Electron Beam

Implementation Method 5

A device according to the invention also includes a pulse generator which is electrically connected to the two hollow cathodes and which generates a bipolar medium-frequency pulsed electrical voltage between the two hollow cathodes

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Implementation Method 6

a large-volume hollow cathode arc discharge plasma is created

Methodology Applied
Scientific EffectPlasma: Plasma

Data Source

PatentEP2795657B1Device for producing a hollow cathode arc discharge plasma
Publication Date: 2018.12.12 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2795657B1 patent drawingFigure 1
  • EP2795657B1 patent drawingFigure 2
  • EP2795657B1 patent drawingFigure 3

AI summary

The invention relates to a device for generating a hollow cathode arc discharge plasma, consisting of two plasma sources (11; 12), each comprising a hollow cathode (13; 14) and an electrode (15; 16) that is associated with the hollow cathode (13; 14) and has an opening extending through the electrode (15; 16), wherein the hollow cathodes (13; 14) of the two plasma sources (11; 12) are connected to a pulse generator (17) that generates a bipolar, medium frequency pulsed voltage between the two hollow cathodes (13; 14). In both plasma sources (11; 12), the hollow cathode (13; 14) is connected in an electrically conductive manner to the associated electrode (15; 16), either directly or with the intercalation of at least one component (38; 39) that delimits the current direction.