Antireflection Coating Resilience Against Substrate Erosion

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Solution Overview

Problem

Existing antireflection films face challenges in maintaining high-performance antireflection effects over time due to substrate erosion and component elution, especially when using metal oxide and metal halide layers, and require improved methods for low-temperature sintering and high reliability.

Innovation Solution

A laminated structure comprising a layer of organic resin and a plate crystal layer of aluminum oxide with a continuously increasing refractive index is formed on a substrate, creating a fine uneven surface that enhances antireflection properties while being resistant to moisture and substrate erosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal oxide or metal halide layer is used to form an antireflection film, then the antireflection effect is improved, but the substrate becomes vulnerable to erosion and component elution due to moisture penetration through voids

Engineering Contradiction:
Improveantireflection effect stabilityVSAvoidsubstrate erosion and component elution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An organic resin layer is introduced as an intermediary barrier between the metal oxide/metal halide antireflection layer and the substrate. This resin layer prevents moisture from penetrating through the voids in the metal oxide layer, thereby protecting the substrate from erosion and preventing elution of substrate components while maintaining the antireflection effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure combining organic resin with metal oxide or metal halide particles. This composite approach allows the resin to provide moisture barrier functionality while the metal oxide/halide particles maintain the antireflection optical properties, achieving both protection and optical performance.

Inventive Principle:
Principle #40Composite materials

2Productivity

If a fine periodic structure is formed using conventional coating methods, then productivity is improved, but manufacturing precision and control over pitch and height are limited

Engineering Contradiction:
Improvefilm formation efficiencyVSAvoidpitch and height control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention replaces conventional mechanical coating methods with a chemical self-assembly process. Metal oxide or metal halide particles are dispersed in an organic resin and applied to the substrate, where they spontaneously form a fine periodic structure through controlled chemical reactions and self-organization, achieving both high productivity and precise structural control.

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

3Reliability

If hot water treatment is applied to form boehmite structure, then antireflection property is improved, but film component elution occurs changing optical characteristics

Engineering Contradiction:
Improveantireflection propertyVSAvoidfilm component stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The organic resin layer serves as a protective intermediary that prevents film component elution during hot water treatment. By forming a stable resin matrix that encapsulates the metal oxide particles, the structure allows boehmite formation to occur for improved antireflection properties while preventing the leaching of film components into the water.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 stable and long-lasting high-performance antireflection effect across the visible and near-infrared regions, maintaining optical characteristics and mechanical strength, and is suitable for various substrates including glass.

Implementation Method 1

a fine periodic structure having an appropriate pitch and height, and thereby shows an excellent antireflection property in a wide wavelength region

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

the liquid phase process (sol-gel process) (Japanese Patent Application Laid-Open No. H09-202649) is subjected to water vapor treatment or hot water dipping treatment

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

the liquid phase process (sol-gel process)

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

a layer of aluminum oxide (alumina) formed by the vacuum film formation process is subjected to water vapor treatment or hot water dipping treatment to form a surface layer into boehmite

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Data Source

PatentEP2977794B1Optical member, optical system using the optical member, and method of manufacturing an optical member
Publication Date: 2018.10.31 CANON KK
  • EP2977794B1 patent drawingFigure 1~2
  • EP2977794B1 patent drawingFigure 3A~3B
  • EP2977794B1 patent drawingFigure 4

AI summary

Provided is an optical member capable of keeping a high performance antireflection effect over a long period of time. The optical member has a laminated structure formed on a surface of a substrate, comprising a layer formed of a crystal containing an oxide or a hydroxide of aluminum or a hydrate thereof, and a layer containing an organic resin as a main component formed between the substrate and the layer formed of a crystal, wherein the substrate is made of glass, wherein the thickness of the layer containing an organic resin is 10 nm or more and 150 nm or less, wherein the organic resin includes an aromatic ring and/or an imide ring in a main chain.