Glazing Anti-Diffusion Layer for Thermal Stability

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Solution Overview

Problem

Existing materials for thermal insulation glazing with high solar factor properties suffer from significant color and optical variations after heat treatment, making them unsuitable for applications requiring consistent aesthetics and performance before and after thermal processing.

Innovation Solution

Incorporating a specific anti-diffusion layer in the dielectric coating to prevent inter-diffusion of elements between high-index and oxide layers, along with an intermediate layer with a thickness less than 5 nm, to maintain refractive index stability and reduce optical variations during heat treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a stack of thin layers with high-index and oxide layers is used to achieve high solar factor and light transmission, then optical performance is improved, but color and optical properties vary significantly after heat treatment

Engineering Contradiction:
Improvesolar factorVSAvoidcolor and optical property stability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

An intermediate layer with refractive index between 1.8 and 2.2 is introduced between the high-index layer (refractive index ≥2.20) and the oxide layer. This intermediate layer acts as a buffer that prevents direct interaction and inter-diffusion between the high-index and oxide layers during heat treatment, thereby maintaining stable color and optical properties while preserving the high solar factor performance of the original stack configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If high-index layers with thickness greater than 10 nm are used to improve light transmission, then optical performance is enhanced, but inter-diffusion occurs during heat treatment causing color variation

Engineering Contradiction:
Improvelight transmissionVSAvoidinter-diffusion and color variation
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The intermediate layer with refractive index between 1.8 and 2.2 serves as a protective barrier between the high-index layer and oxide layer. This intermediate layer prevents inter-diffusion of elements during heat treatment while allowing the high-index layer to maintain its optimal thickness (>10 nm) for maximizing light transmission and optical performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If dielectric coatings are applied to protect silver layers and adjust optical properties, then material durability and optical performance are improved, but the material becomes unsuitable for heat treatment processes

Engineering Contradiction:
Improvematerial durabilityVSAvoidheat treatment compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The dielectric coating structure is modified by introducing an intermediate layer with specific refractive index (1.8-2.2) between the high-index and oxide layers. This parameter change in the dielectric coating structure enhances its thermal stability and resistance to inter-diffusion during heat treatment, making the coating system compatible with heat treatment processes while maintaining protective and optical functions.

Inventive Principle:
Principle #35Parameter changes

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 ensures minimal color and optical variations after heat treatment, maintaining consistent light absorption, transmission, and emissivity values, thus making the material 'matchable' and suitable for use before and after thermal processing.

Implementation Method 1

Incorporating a specific anti-diffusion layer in the dielectric coating to prevent inter-diffusion of elements between high-index and oxide layers

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

by reflecting infrared, thermal or solar radiation, they give the material low-emissivity or solar control functions

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

by reflecting infrared, thermal or solar radiation, they give the material low-emissivity or solar control functions

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 4

the energy flow absorbed then re-emitted towards the interior by the glazing

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3347322B1Glazing including a stack of thin layers
Publication Date: 2021.08.18 SAINT GOBAIN VITRAGE SA
  • EP3347322B1 patent drawingFigure 1~2

AI summary

The invention relates to a material including a transparent substrate coated with a stack of thin layers including a functional metal layer made of silver and two dielectric coatings. The material is characterized in that a bottom dielectric coating located under a functional layer made of silver includes: a high-index layer made of metal oxide, an anti-diffusion layer made of silicon and/or aluminum and at least one oxide layer located above the anti-diffusion layer and having a different composition to that of the anti-diffusion layer, such as a smoothing layer and/or a wetting layer.