Plasma Generator With Dielectric Screen For Field Localization
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Solution Overview
Problem
Existing plasma generators suffer from unstable operation, low efficiency, and reliability issues due to unwanted spurious discharges and high-frequency field leakage, which limits their application scope, plasma density, and chamber size, as well as causing contamination and material etching.
Innovation Solution
The design incorporates a helical coil within a conductive screen with a dielectric-filled gap, a flat coil configuration, and dielectric screens to localize high-frequency fields, reduce eddy currents, and increase inductive coupling, using materials like copper or aluminum alloys for the screen and dielectric materials with permittivity between 2.5 to 50 to manage electromagnetic fields and power supply efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the coil is placed closer to the plasma generation region to increase plasma density, then plasma density increases, but spurious discharges and high-frequency field leakage worsen
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the coil and the plasma generation region. This dielectric layer prevents direct contact between the coil and plasma, thereby eliminating spurious discharges while allowing the coil to remain close to the plasma region for efficient energy transfer and high plasma density.
Solution Approach 2:
The space between the coil and plasma generation region is segmented into distinct zones: the coil winding region, the dielectric layer, and the plasma generation region. This segmentation allows each component to perform its function optimally without interfering with others, preventing field leakage while maintaining close proximity for efficient coupling.
2Volume of moving object
If the working chamber size is reduced to make the device more compact, then device size decreases, but the minimum chamber size required for desired plasma concentration increases
Solution Approach 1:
The dielectric layer thickness is optimized to a specific range (0.5-5mm) to achieve the right balance between allowing sufficient plasma concentration while maintaining compact device size. This parameter optimization enables small chamber volumes without sacrificing plasma quality.
Solution Approach 2:
The dielectric layer provides localized insulation exactly where needed (between coil and plasma region) rather than requiring large distances throughout the entire chamber. This localized approach enables compact overall device size while maintaining optimal plasma generation conditions in the specific region.
3Volume of moving object
If the distance between the coil and conductive screen is reduced to minimize device size, then device compactness improves, but eddy currents and ohmic losses increase
Solution Approach 1:
The dielectric layer serves as an intermediary between the coil and conductive screen, preventing direct electromagnetic coupling that would induce eddy currents in the screen. This allows the screen to be placed close to the coil for device compactness while the dielectric prevents energy loss through eddy currents and ohmic heating.
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 configuration enhances plasma density, purity, and device reliability by preventing spurious discharges, reducing noise and thermal losses, and allowing for more efficient energy transfer, resulting in a more compact and stable plasma generator with improved operational efficiency and extended lifespan.
Implementation Method 1
inductively coupled plasma source... alternating magnetic field... induces a uniform electric field
Implementation Method 2
space between the coil windings and between the coil and screen filled with dielectric
Implementation Method 3
conductive screen with a dielectric-filled gap... localize high-frequency fields, reduce eddy currents
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to devices intended for treatment of materials in gas discharge plasma of low temperature, namely the induction plasma generator, placed inside the process volume (working chamber). The technical problem to be solved by the proposed invention is to increase the efficiency of the device; to improve the reliability of the device, increase purity of plasma environment and increase density of plasma generated; increase the life of device; reduce the level of noise; reduce the size of the device. Plasma generator as per first embodiment comprising a helical coil, placed inside a conducting screen, an inner surface of which is of a nearly cylindrical shape, moreover the space between the coil windings and between the coil and the screen is filled with dielectric, has a flat coil, the distance from plane of the coil to outer surface of dielectric is less than double thickness of the coil, and the distance from plane of the coil to the base of inner surface of the screen is greater than double distance from the plane of the coil to outer surface of dielectric. Plasma generator of the second embodiment has a flat coil, screen in the form of the ring which axis is perpendicular to the plane of the coil, the edge of the ring facing the volume, where it required to create plasma, is closed with dielectric. Plasma generator of the third embodiment has the screen electrically connected to one end of the coil, and the dielectric constant of the dielectric is in the range of 2.5 to 50. Proposed constructive design of generator provides higher plasma density and increased purity of plasma environment than in prior one, under the same conditions in the discharge chamber and at the same HF power supply. Proposed device has high efficiency, is reliable in operation, has a long life and small size.