Plasma Diffuser Design to Reduce Substrate Discolouration in Coating
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Solution Overview
Problem
Plasma coatings often cause unwanted discolouration on dark substrates such as black, grey, and blue surfaces, especially in large-scale production, due to uneven plasma distribution, which limits their application in consumer products where visual appearance is critical.
Innovation Solution
A plasma diffuser is placed between the substrate and electrodes to diffuse the plasma, ensuring a more uniform distribution and reducing discolouration, while maintaining the performance of the coating in terms of oil repellency and washability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma coating is applied to dark substrates, then functional properties (hydrophobicity, scratch resistance) are improved, but discolouration occurs making the substrate darker or rainbow-like
Solution Approach 1:
A plasma diffuser is introduced as an intermediary component between the plasma source and the substrate. The diffuser has a specific structure with inlet and outlet channels that redirect plasma flow, preventing direct plasma-substrate interaction that causes discolouration while maintaining coating functionality.
Solution Approach 2:
The plasma treatment process is segmented into two distinct stages: a first plasma treatment stage that imparts functional properties, and a second plasma treatment stage that removes discolouration. This temporal segmentation allows achieving both functional enhancement and visual quality.
2Reliability
If plasma coating is applied to high gloss surfaces, then functional properties are improved, but the high gloss appearance deteriorates due to discolouration
Solution Approach 1:
The plasma diffuser acts as a mediator that preserves the optical properties of high gloss surfaces by controlling plasma distribution, preventing the formation of discolouration that would otherwise degrade the surface appearance.
Solution Approach 2:
The coating process uses periodic plasma treatment with controlled timing and intensity cycles, applying plasma treatment to build functional coating while using diffuser-mediated plasma flow to prevent discolouration formation.
3Reliability
If plasma coating is applied to smooth surfaces, then functional properties are improved, but discolouration becomes more visible
Solution Approach 1:
The plasma diffuser mediates the plasma-substrate interaction by distributing plasma flow through its channel structure, preventing localized plasma concentration that would cause visible discolouration on smooth surfaces.
Solution Approach 2:
The plasma treatment parameters are changed and optimized for smooth surfaces, using the plasma diffuser to control plasma density and distribution, treating with lower power or shorter duration to prevent discolouration while maintaining functional coating properties.
4Productivity
If batch plasma processing is used, then production capacity is improved, but discolouration is more pronounced due to static coating
Solution Approach 1:
The plasma diffuser is integrated into batch processing equipment as a mediator that enables uniform plasma distribution across multiple substrates simultaneously, maintaining high production capacity while preventing discolouration through controlled plasma flow.
Solution Approach 2:
The batch processing approach is segmented to allow individual substrate treatment zones within the plasma chamber, with the plasma diffuser creating uniform plasma distribution across different positions, preventing discolouration even when treating multiple items together.
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 plasma diffuser significantly reduces or eliminates discolouration on dark substrates, allowing for the use of plasma coatings in consumer products without compromising their performance or appearance, and can be adapted for various substrates and processes.
Implementation Method 1
diffusing a plasma prior to and/or during depositing of said plasma on said substrate to form a coating
Implementation Method 2
A plasma diffuser is placed between the substrate and electrodes to diffuse the plasma, ensuring a more uniform distribution
Implementation Method 3
depositing of said plasma on said substrate to form a coating
Implementation Method 4
plasma diffuser method and apparatus... to deposit plasma coatings, preferably by plasma polymerization
Data Source
AI summary
A method is provided for at least partially preventing discolouration of a substrate by a plasma coating process, by diffusing a plasma prior to and/or during depositing of said plasma on said substrate to form a coating. Also provided is a plasma coating apparatus comprising a plasma diffuser for homogenizing a plasma density nearby a substrate to be coated.