Thermal Insulation Substrate Amorphous Smoothing Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stacks of thin layers on transparent substrates, used for thermal insulation and solar protection, face challenges in maintaining resistivity and optical quality during high-temperature treatments, while also requiring mechanical strength and indistinguishable visual appearance for tempered and non-tempered substrates.
Innovation Solution
A stack comprising a metallic functional layer with dielectric layers, where the functional layer is deposited on a wetting layer directly over a non-crystallized smoothing layer based on a mixed oxide, such as zinc and tin, and an underlying nitride-based layer, ensuring improved crystallization and resistivity without compromising mechanical or optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stack with crystallized wetting layer and dielectric layers is used, then the stack provides thermal insulation and solar protection properties, but the resistivity deteriorates after high-temperature heat treatment
Solution Approach 1:
The patent introduces an amorphous intermediate layer between the crystallized dielectric layer and the crystallized wetting layer. This amorphous layer acts as a mediator that prevents crystal grain growth from the wetting layer into the dielectric layer during high-temperature heat treatment, thereby maintaining the resistivity of the stack while allowing the necessary heat treatment for substrate tempering or bending.
2Reliability
If the functional metallic layer is made thinner to improve resistivity, then the thermal insulation performance improves, but the reflection properties and solar protection capability deteriorate
Solution Approach 1:
The patent changes the physical state parameter of the intermediate layer to amorphous (non-crystalline), which prevents crystal grain boundary formation. This allows the use of thinner functional metallic layers with lower resistivity while maintaining optical properties, because the amorphous layer eliminates the need for thick metallic layers that would otherwise be required to compensate for crystal grain boundary resistance.
3Strength
If high-temperature heat treatment is applied to improve substrate mechanical strength, then the substrate becomes stronger, but the crystallization of the functional layers deteriorates and resistivity increases
Solution Approach 1:
The amorphous intermediate layer serves as a physical barrier that prevents the propagation of crystal grains from the wetting layer into the dielectric layer during high-temperature heat treatment. This intermediary layer allows the substrate to undergo necessary heat treatment for mechanical strength improvement while protecting the functional layers from detrimental crystallization that would increase resistivity.
4Reliability
If a crystallized wetting layer is used to ensure adequate crystalline orientation of the functional layer, then the functional layer crystallization improves, but the interface roughness increases and resistivity deteriorates
Solution Approach 1:
The amorphous intermediate layer provides a smooth interface between the crystallized dielectric layer and the crystallized wetting layer. This intermediary layer eliminates interface roughness that would otherwise result from direct contact between crystallized layers, while still allowing adequate crystalline orientation of the functional layer through the wetting layer.
Solution Approach 2:
The patent applies different crystalline states to different layers: the dielectric layer and wetting layer are crystallized to provide orientation and stability, while the intermediate layer is kept amorphous to provide a smooth interface. This local differentiation of crystalline quality optimizes both functional layer crystallization and interface smoothness.
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 solution enhances the resistivity and maintains optical quality and mechanical strength of the stack, even after heat treatment, while allowing tempered and non-tempered substrates to appear visually identical, thus addressing the limitations of prior art.
Implementation Method 1
This metallic functional layer is deposited in a crystallized form on an equally crystallized wetting layer favoring the adequate crystalline orientation of the metallic layer deposited thereon
Implementation Method 2
The stack is generally obtained by a succession of deposits carried out by a technique using a vacuum such as cathode sputtering possibly assisted by a magnetic field
Implementation Method 3
whether or not the stack undergoes one (or more) thermal treatment(s) at high temperature of the bending, quenching or annealing type
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a substrate (10), especially a transparent glass substrate, provided with a stack of thin layers comprising a functional layer (40) which has infrared reflectance and/or solar radiation reflectance properties and is especially metallic based on silver or a metallic alloy containing silver, and two coatings (20, 60), said coatings consisting of a plurality of dielectric layers (24, 26; 64) such that the functional layer (40) is arranged between the two coatings (20, 60), the functional layer (40) being arranged on a wetting layer (30) which is arranged in turn directly on a subjacent coating (20). The inventive substrate is characterised in that the subjacent coating (20) comprises at least one dielectric layer (24) based on nitride, especially silicon nitride and/or aluminium nitride, and at least one non-crystallised mixed oxide smoothing layer (26), said smoothing layer (26) being in contact with the subjacent wetting layer (30).