Silazane-Based Planarizing Layer for Coated Glass
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Solution Overview
Problem
Existing methods for planarizing the surface of coated glass panes, such as overcoating with silica or polishing, do not achieve a sufficiently smooth surface efficiently, with polishing being time-consuming and providing limited improvement.
Innovation Solution
A coated glass pane structure comprising a glass pane with an underlayer including a lower anti-reflection layer, a silver-based functional layer, and further anti-reflection layers, where at least one layer based on silica or organosilica is formed by partially or completely converting a silazane layer, resulting in a smooth surface with reduced roughness and enhanced visible light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If overcoating with silica is used to planarise the surface, then the surface smoothness is improved, but the process is time-consuming and does not achieve sufficiently smooth surface
Solution Approach 1:
The patent changes the chemical composition parameter by using silazane-based precursors instead of conventional silica precursors. This chemical parameter change enables the coating process to achieve Sa ≤ 2 nm surface smoothness without requiring time-consuming polishing steps, thus resolving the contradiction between manufacturing precision and processing time
Solution Approach 2:
The patent employs a composite coating structure comprising multiple layers with different functions: a silazane-based planarising layer (Sa ≤ 2 nm), a silver-based functional layer for optical properties, and dielectric anti-reflection layers. This composite structure achieves both high surface smoothness and functional performance simultaneously, overcoming the limitations of single-material coatings
2Manufacturing precision
If polishing is used to achieve a planar surface, then the surface roughness is reduced, but the process is time-consuming
Solution Approach 1:
The patent replaces the mechanical polishing process with a chemical deposition approach using silazane-based precursors. The chemical conversion process naturally produces a planarised surface (Sa ≤ 2 nm) without requiring mechanical abrasion, thereby eliminating time-consuming polishing operations while achieving superior surface planarity
Solution Approach 2:
The silazane-based coating is applied as a preliminary layer before final functional coatings are deposited. This preliminary planarising layer prepares the surface in advance, ensuring that subsequent layers are deposited on a uniformly smooth substrate, which eliminates the need for post-deposition polishing and reduces overall processing time
3Strength
If the underlayer is rough, then the coating adhesion may be improved, but the visible light transmission is reduced and the surface is prone to marking and scratches
Solution Approach 1:
The patent applies different surface quality requirements to different functional layers. The silazane-based planarising layer provides extreme smoothness (Sa ≤ 2 nm) for optical surfaces requiring high light transmission and scratch resistance, while the silver-based functional layer and dielectric layers provide adhesion and optical functionality. Each layer is optimised for its specific local function, resolving the contradiction between adhesion and optical performance
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 method achieves a high degree of planarization, reducing surface roughness, haze, and improving hydrophobicity, making the glass pane less prone to marking and scratches, while maintaining high visible light transmission.
Implementation Method 1
at least one layer based on silica and/or an organo silica, wherein: said at least one layer based on silica and/or an organo silica is obtained by partially or completely converting at least one layer based on one or more silazane
Data Source
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Figure 3
AI summary
Methods are disclosed for planarisation of a coated glass substrate by deposition of a silazane based layer thereon. Coated substrates according to the invention exhibit improved properties in terms of reduced roughness, lower haze and higher visible light transmission and the coated surface may be exposed to the external environment, for example as surface 1 or surface 4 of a double glazing unit. The resulting smooth surface is less susceptible to marking and scratch damage, and offers enhanced surface energy (improved hydrophobicity).