Organic-Inorganic Interference Coating Lamination for Curved Optical Substrates

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Solution Overview

Problem

Mineral interference coatings on optical articles, such as ophthalmic lenses, are fragile and prone to cracking due to mechanical and thermal stresses, limiting their curvature range and optical integrity when applied to curved surfaces.

Innovation Solution

A process involving a thermoplastic film coated with a multilayer interference coating containing organic-inorganic layers, which are deposited under vacuum, is used to laminate the film onto an optical article, reducing mechanical stress and enhancing the coating's resistance to cracking and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mineral interference coating is applied to a curved optical surface, then the optical article gains antireflection properties, but the coating becomes prone to cracking under mechanical and thermal stress

Engineering Contradiction:

Improvecoating integrityVSAvoidcoating resistance to cracking

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent modifies the chemical composition and physical parameters of the coating by incorporating organic-inorganic hybrid materials with different mechanical properties than traditional mineral coatings. This changes the coating's elasticity and stress distribution characteristics, allowing it to withstand curvature-induced stresses without cracking.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite organic-inorganic hybrid materials combining the optical properties of inorganic materials with the mechanical flexibility of organic materials. This composite structure provides both the desired optical performance and enhanced resistance to mechanical and thermal stress on curved surfaces.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the curvature of the optical article is increased, then the optical design flexibility is improved, but the interference coating is more likely to crack

Engineering Contradiction:

Improvecurvature rangeVSAvoidcoating integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

By changing the material parameters of the coating to include organic-inorganic hybrids with appropriate elastic moduli and thermal expansion coefficients, the coating can accommodate a broader range of curvatures without developing cracks that would compromise reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs thin film structures with controlled thickness and composition that can flex and deform elastically to match curved optical surfaces. The organic-inorganic hybrid nature provides the necessary flexibility while maintaining coating integrity across different curvature ranges.

Inventive Principle:

Principle #30Flexible shells and thin films

3Area of stationary object

If the functional film is deformed to match the curvature of the optical article, then the coating covers the curved surface, but the film experiences increased mechanical stress and deformation

Engineering Contradiction:

Improvecoating coverage areaVSAvoidmechanical stress in film

Core Design Contradiction:

Area of stationary objectVSStress or pressure

Solution Approach 1:

By adjusting the material parameters of the functional film to include organic-inorganic hybrid materials with appropriate mechanical properties, the film can be deformed to cover curved surfaces while experiencing reduced mechanical stress compared to traditional rigid materials.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses flexible thin film structures that can conform to curved optical surfaces. The organic-inorganic hybrid composition provides the necessary flexibility and stress distribution characteristics to cover the entire curved surface area while minimizing mechanical stress and preventing deformation-induced defects.

Inventive Principle:

Principle #30Flexible shells and thin films

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 process allows for a broader range of curvature applications without cracking, maintains optical properties, and increases the critical temperature for cracking, ensuring improved durability and optical transparency.

Implementation Method 1

at least one of the layers of the interference coating being a layer of organic-inorganic nature that has been deposited under vacuum

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Data Source

PatentUS10732324B2Method for laminating an interference coating comprising an organic/inorganic layer, and item thus obtained

Publication Date: 2020.08.04 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

The invention relates to a method for preparing an optical system item having a non-zero radius of curvature and coated with an interference coating. Said method includes: a) providing a thermoplastic film coated with a multilayer interference coating containing at least one layer having a refractive index of greater than 1.65 and at least one layer having a refractive index of less than or equal to 1.65, at least one of the interference coating layers being a vacuum-deposited organic/inorganic layer, b) laminating said coated thermoplastic film, by means of an adhesive layer, onto an optical system item including a substrate, and c) recovering said optical system item, including a substrate coated with the adhesive layer, from the thermoplastic film and the multilayer interference coating.