Titanium Oxide Organosilicate Hybrid Coating for Ophthalmic Lenses

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Solution Overview

Problem

Existing ophthalmic lenses with interference coatings face issues of thermomechanical weakness, particularly in high refractive index layers, leading to cracking under mechanical and thermal stresses, and challenges in deposition processes that can result in defects like scratches and parasitic reflections.

Innovation Solution

A transparent material with a high refractive index is developed by depositing a layer of titanium oxide and an organosilicon compound using an ion beam, enhancing thermomechanical properties and transparency, and a process involving vacuum deposition with ion assistance to create a multilayer interference coating with improved adhesion and resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional inorganic materials (e.g., titanium oxide) are used for high refractive index layers, then optical performance is improved, but thermomechanical strength deteriorates leading to cracking under stress

Engineering Contradiction:

Improverefractive indexVSAvoidthermomechanical strength

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The patent applies composite materials by combining inorganic titanium oxide with organic silane compounds to form a hybrid coating layer. This composite structure integrates the high refractive index property of titanium oxide with the flexibility and crack resistance of organic polymers, resolving the contradiction between optical performance and thermomechanical strength

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the coating by incorporating organic-inorganic hybrid compounds with specific molecular structures. This parameter change transforms the brittle inorganic material into a more resilient hybrid material that maintains high refractive index while improving resistance to thermal and mechanical stress

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If mineral interference coatings are applied to prevent reflections, then optical quality is improved, but resistance to mechanical deformation and thermal stress deteriorates

Engineering Contradiction:

Improveoptical qualityVSAvoidresistance to cracking

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent replaces conventional mineral interference coatings with an organic-inorganic hybrid coating that combines the optical properties of mineral materials with the flexibility of organic polymers. This composite approach maintains anti-reflective optical quality while significantly improving resistance to cracking under mechanical and thermal stress

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a hybrid coating with differentiated properties at the molecular level, where organic and inorganic components are distributed to provide both optical functionality and mechanical resilience in the same coating layer

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If liquid deposition techniques are used to deposit organic/inorganic layers, then ease of manufacture is improved, but process duration and difficulty of controlling defects increase

Engineering Contradiction:

Improvedeposition process simplicityVSAvoidprocess duration

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces liquid-phase deposition with vapor-phase deposition techniques, substituting a chemical/mechanical process with a physical vapor deposition process. This substitution reduces process duration and improves control over layer formation, eliminating the defects associated with liquid deposition while maintaining ease of manufacture

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 ophthalmic lenses with enhanced thermomechanical properties, improved resistance to cracking, and stable optical performance, addressing the limitations of conventional high refractive index materials and deposition techniques.

Implementation Method 1

depositing, on said main surface of the substrate, a layer A of a material having a refractive index of greater than or equal to 1.8... which has been obtained by vacuum deposition with the assistance of a source of ions

Methodology Applied

Scientific EffectIon beam deposition: Ion Beam

Implementation Method 2

vacuum deposition with the assistance of a source of ions

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Data Source

PatentUS10585211B2Article having optimised thermomechanical properties, comprising a layer of titano-organic nature

Publication Date: 2020.03.10 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

The invention relates to an article comprising a substrate having at least one major surface coated with a layer A of a material obtained by ion beam assisted vacuum deposition of at least one titanium oxide and of at least one organosilicate compound B, said material having a refractive index at 550 nm higher than or equal to 1.8, an extinction coefficient k at 550 nm lower than or equal to 0.02, and an H:E ratio higher than or equal to 0.046, where H and E designate the hardness of the material and the elastic coefficient of the material, respectively.