Method for preparing Anti-reflective coatings and coating obtained therefrom

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Solution Overview

Problem

Existing anti-reflective coating technologies face challenges in achieving stable, reproducible optical and mechanical properties on an industrial scale, particularly with the use of nano-particles and acid catalysts, which complicates the process and affects durability and performance.

Innovation Solution

A process involving surface-modified nano-particles with a metal oxide-based binder, where nano-particles are reacted with alkoxy silanes as surface modifying agents, pre-hydrolysed alkoxy silane binders are used, and the mixture is applied to a substrate with controlled composition ratios to achieve stable and durable anti-reflective coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acid catalysts are used to hydrolyze the binder in the presence of nano-particles, then anti-reflective properties are achieved, but the process becomes difficult to implement on an industrial scale with poor reproducibility

Engineering Contradiction:
Improvereproducibility of optical performanceVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the acid catalyst from the coating composition, eliminating the source of reproducibility issues and process complexity. The binder is pre-hydrolyzed separately before application, extracting the hydrolysis step from the final coating process and eliminating the need for acid catalysts during application.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The binder is pre-hydrolyzed to form oligomeric species before the coating is applied to the substrate. This preliminary action allows the binder to be prepared in advance with controlled properties, eliminating the need for acid catalysts during the coating application and curing stages, thereby improving reproducibility and simplifying the industrial process.

Inventive Principle:
Principle #10Preliminary action

2Strength

If surface-modified nano-particles with metal oxide-based binder are used, then mechanical durability and stability are improved, but the composition becomes more complex

Engineering Contradiction:
Improvemechanical durabilityVSAvoidcomposition complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent uses surface-modified nano-particles where the surface modification creates a composite structure that enhances mechanical durability. The nano-particles are coated with a layer that provides both structural integrity and chemical stability, resulting in a composite material that improves strength while the modification process is integrated into the particle manufacturing.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The surface modification of nano-particles creates local quality differences between the core and surface of the particles. The core provides the base properties while the surface coating provides enhanced mechanical durability and stability, allowing different regions of the same particle to serve different functions.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If pre-hydrolysed binder is used to achieve stable coating composition, then the coating stability is improved, but the manufacturing process steps increase

Engineering Contradiction:
Improvecoating composition stabilityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The binder is pre-hydrolyzed to form oligomeric species before the coating is applied. This preliminary action stabilizes the binder composition and eliminates the need for acid catalysts during application and curing, improving composition stability while the pre-hydrolyzed binder can be stored and transported conveniently.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The hydrolysis step is extracted from the coating application process and performed separately in advance. This separates the complex chemical transformation from the simple application process, allowing the coating composition to be stable and ready-to-apply while the hydrolysis is performed under controlled conditions before use.

Inventive Principle:
Principle #2Taking out (Extraction)

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 results in coatings with improved reproducibility, mechanical durability, and anti-reflective properties, maintaining stability and performance across various substrates, including glass and organic materials, with reduced reflection and enhanced scratch resistance.

Implementation Method 1

reacting the mixture for sufficient time to hydrolyse the reactive groups of the surface modifying agent

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

grafting the surface modifying agent to the surface of the nano-particles

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

pre-hydrolysing an alkoxy silane binder

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

a substance that can chemically cross-link the particles and preferably also between the particles and a substrate

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 5

The optical function is achieved by the effective refractive index of the coating being lower than that of the substrate leading to a gradient of refractive index from that of air to that of the substrate

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 6

This leads to a reduction in the amount of light reflected

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

Data Source

PatentEP1984763B1Method for preparing Anti-reflective coatings and coating obtained therefrom
Publication Date: 2020.09.02 DSM IP ASSETS BV

AI summary

The invention relates to a processes and compositions for preparing anti-reflective coatings.