Glazing Stack With Localized Blocking Layers For Neutral Reflection

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Solution Overview

Problem

Existing glazing technologies with three metallic functional layers suffer from unsatisfactory aesthetic appearance, high reflection levels, and low selectivity, making them unsuitable for buildings and vehicles exposed to strong sunlight, as they either require artificial lighting or cause mirror-like reflections.

Innovation Solution

A transparent substrate with a stack of thin layers comprising three functional metal layers and four antireflection coatings, where the thickness of the metal layers increases away from the substrate, and blocking layers are concentrated around the second functional layer, achieving high selectivity and aesthetically pleasing neutral colors in reflection and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stack with three metallic functional layers is used to optimize solar protection, then the solar factor is reduced and selectivity is increased, but the aesthetic appearance becomes unsatisfactory with unsightly colors and high reflection levels

Engineering Contradiction:
Improvesolar control performanceVSAvoidaesthetic appearance
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by concentrating blocking layers specifically around the second functional metal layer rather than uniformly distributing them. This localized approach selectively controls the optical properties in the critical region where the second metal layer interacts with incoming radiation, thereby improving aesthetic appearance by reducing unwanted colors and reflections while preserving the solar control function of the complete stack

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by varying the thickness of functional metal layers (increasing from first to third layer) and strategically positioning blocking layers with specific thicknesses (greater than 1 nm). These parameter adjustments optimize the balance between solar factor reduction and aesthetic appearance, achieving neutral blue-green colors and reduced reflection levels while maintaining high selectivity

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the light transmission is reduced to eliminate glare, then solar control is improved, but artificial lighting becomes compulsory due to insufficient light penetration

Engineering Contradiction:
Improveglare eliminationVSAvoidlight transmission
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent uses parameter changes by optimizing the thickness of each functional metal layer and the positioning of blocking layers to achieve a specific light transmission range. This allows the glazing to eliminate glare through controlled reflection while maintaining sufficient light transmission for natural illumination, avoiding the need for artificial lighting

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high exterior and interior reflection is achieved to improve solar control, then more solar energy is reflected, but visibility through the glazing is reduced due to mirror-like reflections

Engineering Contradiction:
Improvesolar control performanceVSAvoidvisibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by concentrating blocking layers around the second functional metal layer, which is positioned to interact with incoming solar radiation. This localized blocking approach controls the reflection characteristics specifically in the solar spectrum range, achieving high solar control performance while maintaining visibility in the visible spectrum range through optimized layer configuration

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 provides a high selectivity ratio (TL/g) greater than 2.2, low light reflection, and neutral blue-green colors in both external and internal reflections, maintaining good insulation and visibility without mirror effects, even under varying angles of observation.

Implementation Method 1

a stack of thin layers comprising several functional layers able to act on solar radiation and/or long wave infrared radiation

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

functional layers able to act on solar radiation and/or long wave infrared radiation

Methodology Applied
Scientific EffectInfrared Radiation: Infrared Radiation

Implementation Method 3

each functional layer is placed between two antireflection coatings each generally comprising several antireflection or dielectric layers

Methodology Applied
Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Implementation Method 4

These stacks are generally obtained by a succession of depositions carried out by a technique using vacuum such as cathode sputtering

Methodology Applied
Scientific EffectVacuum deposition: Physical Vapour Deposition

Implementation Method 5

cathode sputtering possibly assisted by a magnetic field

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 6

cathode sputtering possibly assisted by a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2991944B1Substrate provided with a stack having thermal properties
Publication Date: 2020.01.08 SAINT GOBAIN VITRAGE SA
  • EP2991944B1 patent drawingFigure 1
  • EP2991944B1 patent drawingFigure 2~2.c
  • EP2991944B1 patent drawingFigure 3~3.c

AI summary

The invention relates to a transparent substrate comprising a stack of thin layers successively comprising, starting from the substrate, an alternation of three metallic functional layers, in particular of functional layers based on silver or on silver‑comprising metal alloy, and of four antireflective coatings, each antireflective coating comprising at least one dielectric layer, so that each metallic functional layer is positioned between two antireflective coatings, characterized in that: - the thicknesses of the metallic functional layers, starting from the substrate, increase as a function of the distance from the substrate, - the second metallic functional layer is directly in contact with a blocking layer, referred to as second blocking layer, chosen from a blocking underlayer and a blocking overlayer, respectively referred to as second blocking underlayer and second blocking overlayer, - the second blocking underlayer and/or the second blocking overlayer exhibits a thickness of greater than 1 nm.