Substrate Coating Process Preventing Roller Marks
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Solution Overview
Problem
The existing methods for depositing coatings on both sides of glass substrates in horizontal coaters often result in defects like rectilinear marks after heat treatment, particularly in thicker glass substrates, due to contact with conveying rollers, which are not visible before heat treatment.
Innovation Solution
A process involving the deposition of a temporary protective carbon layer on one side of the coating, followed by turning the substrate to allow contact with rollers in a second deposition device, where a second coating is applied, with the option of depositing another protective layer on the second side, using magnetron sputtering devices, and subsequent removal of the protective layer during heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is deposited horizontally on conveying means in a magnetron device, then the deposition process can be carried out efficiently, but rectilinear marks appear on the final glazing after heat treatment due to contact with the conveying rollers
Solution Approach 1:
A temporary protective layer is deposited between the coating and the conveying rollers to prevent direct contact and mark formation. This intermediary layer acts as a sacrificial barrier that protects the coating during handling and is subsequently removed after heat treatment, eliminating the source of rectilinear marks while maintaining deposition efficiency.
Solution Approach 2:
The protective layer is deposited in advance before the substrate undergoes heat treatment and handling operations. This preliminary protective action prevents marks from forming during subsequent processing steps, and the layer is designed to be removable after it has served its protective function.
2Manufacturing precision
If a temporary protective layer is deposited on the coating, then marks are prevented during handling, but an additional deposition step is required
Solution Approach 1:
The deposition of the protective layer is merged with the existing coating deposition process in the same magnetron device, using the same conveying means and vacuum environment. This integration adds minimal complexity while providing effective protection against marks during handling and heat treatment.
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 process prevents the appearance of marks on the coated surfaces after heat treatment, maintaining the anti-reflective properties of the coatings and ensuring defect-free glazing with improved visibility and solar control.
Implementation Method 1
the deposition of the material constituting a layer of the stack is obtained by spraying a target of said material or a precursor of said material (constituting the cathode) under the effect of particles positives created in a plasma of a so-called sputtering gas
Implementation Method 2
particles positives created in a plasma of a so-called sputtering gas
Implementation Method 3
subsequent removal of the protective layer during heat treatment
Data Source
Figure 1
Figure 2
AI summary
A method for depositing coatings, in particular stacks of thin films on both faces of a glass substrate, comprising the following steps: in a first device, deposition on one face of a first coating, deposition on said first coating of a temporary protective layer; turning over said substrate, so that the coated face of the coating and the protective layer are in contact with conveying means to a second deposition device; in a second deposition device, deposition on the second face of a second stack of layers, identical or different from the first stack.