Silver Thin Film Stack Asymmetric Blocking Layers

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Solution Overview

Problem

Current silver-based glazing materials face challenges in achieving a shiny silver appearance in reflection, neutral transmission colors, and high external reflection without increasing the solar factor, while maintaining good insulation and vision, especially in high sunlight conditions.

Innovation Solution

A transparent substrate coated with a stack of thin layers, including a dielectric coating, a lower blocking layer, a functional silver-based metal layer, and a thick upper blocking layer based on nickel or chromium, positioned on the interior face of the glazing, which allows incident light to pass through the dielectric coating before the silver layer, enhancing external reflection and maintaining energy performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional blocking layer configuration is used, then the silver layer is protected from oxidation, but the aesthetic appearance and external reflection properties are insufficient

Engineering Contradiction:
Improveprotection of silver layerVSAvoidexternal reflection
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different blocking layer configurations at different locations relative to the silver layer. Specifically, it uses a thicker upper blocking layer (3-10 nm) above the silver layer and a thinner lower blocking layer (0.5-2 nm) below the silver layer, optimizing both protection and aesthetic appearance for different functional requirements

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces asymmetric blocking layer thicknesses where the upper blocking layer is significantly thicker than the lower blocking layer. This asymmetric configuration creates the desired shiny silver appearance and high external reflection while maintaining adequate protection, breaking the conventional symmetric or predominantly lower blocking layer approach

Inventive Principle:
Principle #4Asymmetry

2Illumination intensity

If the blocking layer thickness is increased to improve appearance, then external reflection increases, but the solar factor may increase

Engineering Contradiction:
Improveexternal reflectionVSAvoidsolar factor
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent optimizes the thickness parameters of the blocking layers to achieve the desired balance. By setting the upper blocking layer thickness to 3-10 nm and the lower blocking layer to 0.5-2 nm, it achieves high external reflection (greater than conventional configurations) while maintaining solar factor performance through precise parameter control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent concentrates the blocking layer thickness increase primarily in the upper region (away from the substrate) where it enhances external reflection and aesthetic appearance, while keeping the lower blocking layer thin to minimize impact on solar factor and energy performance

Inventive Principle:
Principle #3Local quality

3Reliability

If multiple blocking layers are used to protect the silver, then the protection is improved, but the stack complexity increases

Engineering Contradiction:
Improveprotection of silver layerVSAvoidstack structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a simple two-layer blocking structure (upper and lower blocking layers) with distinct thicknesses optimized for their respective locations. This avoids the complexity of multiple alternating layers while providing adequate protection through the strategically configured upper and lower blocking layers

Inventive Principle:
Principle #3Local quality

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 achieves a high external reflection, aesthetically pleasing neutral colors in transmission, and excellent energy performance without compromising solar factor values, ensuring good insulation and vision while maintaining a shiny silver appearance.

Implementation Method 1

the properties of silver-based stacks, such as energy or optical performance, also result from precise control of the optical interference effects between the different layers making up the stack

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

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

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

in the case of glass substrates, it may involve thermal tempering treatment intended to mechanically reinforce the substrate by creating strong compressive stresses on its surface

Methodology Applied
Scientific EffectThermal tempering: Heat Treatment

Data Source

PatentEP3319920B1Material comprising a stack of thin layers
Publication Date: 2019.05.22 SAINT GOBAIN VITRAGE SA

AI summary

The invention relates to a material comprising a transparent substrate coated with a stack of thin layers comprising a single functional metal layer containing silver, the stack comprising, starting from the substrate: a dielectric coating comprising at least one dielectric layer; optionally a lower blocking layer arranged below the functional metal layer containing silver and in contact with same; a functional metal layer containing silver; and an upper blocking layer arranged above the functional metal layer containing silver and in contact with same.