Temporary Protective Layer for Electrochromic Stack

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Solution Overview

Problem

Glass substrates coated with electrochromic stacks are vulnerable to mechanical and chemical damage during production, transformation, and handling, leading to defects such as scratches, short-circuits, and degradation of optical and energy properties, and existing protective methods like silica or alumina layers lack sufficient scratch resistance or are difficult to remove without harming the stack.

Innovation Solution

A temporary protective layer with an organic polymeric matrix, 1 μm to 30 μm thick, is applied to the electrochromic stack, removable by heat treatment between 300° C. and 500° C. for 180 to 240 seconds, which preserves the stack's properties and can withstand cutting operations without leaving residues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a protective layer based on silica and/or alumina is applied to the electrochromic stack, then the scratch resistance is improved, but the layer cannot be removed and may cause defects

Engineering Contradiction:
Improvescratch resistanceVSAvoidremovability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies a temporary protective layer that is designed to be removed after serving its protective function. This disposable approach allows the layer to provide scratch resistance during handling and processing, then be cleanly removed without leaving residues or causing defects on the electrochromic stack.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The protective layer's properties are changed through heat treatment parameters (temperature and time) that enable its removal. By controlling the thermal parameters, the layer transitions from a protective state to a removable state, allowing it to be degraded and eliminated without damaging the underlying electrochromic stack.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If transparent films of peelable adhesive polymers are used as protective layers, then the removability is improved, but they leave residues and marks on the electrochromic stack

Engineering Contradiction:
ImproveremovabilityVSAvoidquality of final glazing
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The protective layer is designed as a temporary, disposable element that provides protection during manufacturing and handling, then is completely removed without leaving any residues or marks on the electrochromic stack, ensuring the final product quality is not compromised.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces adhesive bonding with thermal bonding mechanisms. Instead of using adhesive polymers that leave residues, the protective layer is bonded and removed through controlled heat treatment, substituting chemical adhesion with thermal processes that leave no harmful residues on the electrochromic stack.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If the protective layer is removed by heat treatment at high temperature (>600° C.), then the removal is effective, but the electrochromic material crystallizes and loses function

Engineering Contradiction:
Improveremoval efficiencyVSAvoidfunctional properties of electrochromic stack
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the heat treatment parameters (temperature and time) to a specific range that enables effective removal of the protective layer while staying below the crystallization temperature of the electrochromic material. This precise parameter control allows the removal process to occur without compromising the functional properties of the electrochromic stack.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using excessive heat treatment that would guarantee complete removal but risk damaging the electrochromic material, the patent applies a partial heat treatment at controlled temperatures and durations. This partial action is sufficient to remove the protective layer while maintaining the integrity and functionality of the underlying electrochromic stack.

Inventive Principle:
Principle #16Partial or excessive action

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 temporary protective layer effectively shields the electrochromic stack from mechanical and chemical damage, allowing for easy removal without affecting the stack's performance, ensuring continuous production and maintaining the stack's optical and energy properties.

Implementation Method 1

removable by heat treatment at a temperature of between 300° C. and 500° C., for a period of between 180 s and 240 s

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentUS12007658B2Method for protecting a glass substrate coated with an electrochromic stack and method for producing an insulating glazing
Publication Date: 2024.06.11 SAINT GOBAIN VITRAGE SA

AI summary

A process for protecting a glass substrate coated with an electrochromic stack, includes depositing a temporary protective layer on the electrochromic stack, the temporary protective layer including an organic polymeric matrix and having a thickness of between 1 μm and 30 μm, and the temporary protective layer being removable by heat treatment at a temperature of between 300° C. and 500° C., fora period of between 180 s and 240 s.