Method for manufacturing a mirror with no copper layer

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Solution Overview

Problem

Conventional mirror manufacturing processes use toxic lead-containing paints to protect copper layers from corrosion, which is environmentally and health-wise undesirable, and lack effective alternatives for maintaining mechanical strength and corrosion resistance without copper layers.

Innovation Solution

A method involving a glass substrate coated with a silver layer, treated with a single passivation solution containing bismuth and tin ions, followed by the application of lead-free paints, which enhances corrosion and aging resistance comparable to copper-protected mirrors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a copper layer is used to protect the silver layer, then corrosion resistance is improved, but toxicity increases due to the need for lead-containing paints

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidtoxicity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention removes the copper layer from the mirror structure, extracting the harmful element that necessitated lead-containing protective paints. The silver layer is directly protected by lead-free paints through a passivation treatment, eliminating the source of toxicity while maintaining corrosion resistance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters of the protective system by replacing copper-based protection with a passivation treatment combined with lead-free paints. The passivation solution modifies the surface properties of the silver layer, enabling effective protection without toxic materials.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If a copper layer is removed to eliminate toxicity, then environmental friendliness is improved, but corrosion resistance deteriorates

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidcorrosion resistance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention introduces a passivation solution as an intermediary between the silver layer and the lead-free paints. This passivation treatment creates a protective interface that enhances corrosion resistance, compensating for the removal of the copper layer while allowing the use of environmentally friendly lead-free paints.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If lead-free paints are used instead of lead-containing paints, then environmental safety is improved, but protective effectiveness worsens

Engineering Contradiction:
Improveenvironmental safetyVSAvoidprotective effectiveness
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention applies a passivation treatment in advance before applying the lead-free paints. This preliminary action prepares the silver layer surface, creating optimal conditions for the lead-free paints to form an effective protective barrier, thereby compensating for the inherently lower protective effectiveness of lead-free paints compared to lead-containing ones.

Inventive Principle:
Principle #10Preliminary 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 method provides effective protection against corrosion and aging, maintains mechanical strength, and eliminates the need for toxic lead-containing paints, achieving results comparable to copper-protected mirrors while being environmentally friendly.

Implementation Method 1

Place the glass substrate in contact with a silver plating solution so as to form a layer of silver on the substrate

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

Contact the silver layer with a single passivation solution comprising bismuth ions and tin ions

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Data Source

PatentEP2895435B1Method for manufacturing a mirror with no copper layer
Publication Date: 2020.12.09 AGC GLASS EUROPE SA

AI summary

The invention relates to a method for manufacturing a mirror with no copper layer, comprising a step of passivation of the silver layer with at least one passivation solution comprising bismuth ions.