Coated Glazing Surface Topography for Thermal Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coated glazings used in architectural, automotive, and technical applications often experience cohesive failures during thermal bending and tempering processes, which can lead to undesirable cracks and damage in the coating stack.
Innovation Solution
A coated glazing structure comprising a transparent glass substrate, a layer based on an oxide of a metal or metalloid, and a further layer, where the layer adjacent the glass substrate has a modified surface topography with an arithmetical mean height of at least 4.0 nm, reducing cohesive failures during thermal bending and tempering operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glazing is thermally bent and/or tempered to obtain desired product characteristics, then the glazing achieves improved heat loss and/or gain regulation, but cohesive failures occur within the coating stack resulting in cracks and damage
Solution Approach 1:
The patent applies preliminary action by creating a roughened surface layer (with Sa ≥ 4.0 nm) on the substrate before coating deposition. This pre-treatment modifies the surface topography to enhance adhesion and prevent cohesive failures during subsequent thermal bending and tempering operations, thereby resolving the contradiction between achieving desired thermal performance and maintaining coating integrity
Solution Approach 2:
The patent applies local quality by creating a differentiated surface structure only in the layer adjacent to the glass substrate, while other layers maintain their standard properties. The roughened surface (Sa ≥ 4.0 nm) is localized to the first layer, providing enhanced mechanical interlocking and adhesion precisely where needed during thermal processing, without affecting the overall optical and thermal performance of the complete coating stack
2Reliability
If the surface of the layer adjacent to the glass substrate is roughened with Sa of at least 4.0 nm, then cohesive failures are reduced during thermal bending, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the surface topography parameter (Sa) to be at least 4.0 nm through controlled roughening processes. This quantitative specification transforms the surface treatment into a measurable and controllable process parameter, enabling consistent reproduction of the adhesion-enhancing effect while managing manufacturing complexity through defined quality criteria
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 modified surface topography of the layer adjacent the glass substrate significantly reduces cohesive failures within the coating stack during thermal bending and tempering, enhancing the durability and reliability of the coated glazing.
Implementation Method 1
the layer adjacent to the transparent glass substrate comprises a surface that, prior to a coating of the surface, has an arithmetical mean height of the surface value, Sa, of at least 4.0 nm when tested in accordance with ISO 25178-2:2012
Data Source
AI summary
A coated glazing includes at least the following layers in sequence: a transparent glass substrate, a layer based on an oxide of a metal and/or a layer based on an oxide of a metalloid, and a further layer, wherein either the layer based on an oxide of a metal or the layer based on an oxide of a metalloid is adjacent the transparent glass substrate. The layer that is adjacent the transparent glass substrate has a surface that, prior to a coating of the surface, has an arithmetical mean height of the surface value, Sa, of at least 4.0 nm when tested in accordance with ISO 25178-2:2012, and the coated glazing exhibits an average haze value of at least 0.47% when tested in accordance with ASTM D1003-13.