Multilayer Interferential Coating for Optical Lens Abrasion Resistance
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Solution Overview
Problem
Existing optical articles, such as ophthalmic lenses, face challenges in achieving improved abrasion resistance and thermal resistance while maintaining optical and mechanical performance, with existing coatings often compromising on adhesion or requiring heating processes that are not suitable for all substrates.
Innovation Solution
A multilayer interferential coating system is applied to an optical article, comprising a substrate with a thick sub-layer and specific refractive index layers, including high and low refractive index sheets, which enhances abrasion resistance and adhesion without compromising optical performance and avoids heating the substrate during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a relatively thick sub-layer or increased total thickness of anti-reflection coating is used to improve abrasion resistance, then abrasion resistance is improved, but the coating becomes more sensitive to photo-degradation and may require heating processes that are not suitable for all substrates
Solution Approach 1:
The patent changes the chemical composition parameters of the coating layers, specifically using silicon oxide (SiO2) and silicon oxynitride (SiOxNy) with controlled oxygen and nitrogen content ratios. This chemical parameter change allows achieving abrasion resistance without increasing thickness to problematic levels or requiring heating processes
Solution Approach 2:
The patent employs composite coating structures combining multiple materials with different properties: silicon oxide layers provide abrasion resistance while silicon oxynitride layers provide optical performance and reduced photo-degradation sensitivity. This composite approach resolves the contradiction by distributing functions across different material components
2Reliability
If ion-assisted vapor deposition is used to increase compressive stress and improve coating properties, then coating durability is improved, but delamination may occur due to excessive compressive stress
Solution Approach 1:
The patent modifies deposition parameters by controlling oxygen and nitrogen partial pressures during plasma-enhanced chemical vapor deposition (PECVD). This parameter control adjusts the chemical composition and stress state of coating layers, achieving durability without excessive compressive stress that would cause delamination
Solution Approach 2:
The patent applies different material compositions and deposition conditions to different layers within the coating system. Each layer is locally optimized with specific SiO2/SiOxNy combinations and thicknesses to achieve appropriate stress distribution, preventing delamination while maintaining overall durability
3Strength
If the ratio of SiO2 layer thickness to TiO2 layer thickness is increased to improve abrasion resistance, then abrasion resistance is improved, but the coating requires heating processes that are not suitable for all substrates
Solution Approach 1:
The patent changes the material composition from traditional TiO2 high-refractive-index layers to silicon-based materials (SiO2 and SiOxNy) with controlled stoichiometry. This compositional parameter change eliminates the need for high-temperature heating processes while maintaining abrasion resistance through the inherent properties of silicon oxide materials
Solution Approach 2:
The patent replaces thermal processing (heating) with chemical vapor deposition processes that operate at lower temperatures. The desired coating properties are achieved through chemical composition control rather than thermal treatment, substituting a mechanical/chemical process for a thermal process to improve manufacturing compatibility
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 optical articles with improved abrasion resistance, better adhesion, and high critical temperature, maintaining or improving optical and mechanical performances, and can be integrated into standard manufacturing processes without heating the substrate.
Implementation Method 1
a multilayer interferential coating system is applied to an optical article, comprising a substrate with a thick sub-layer and specific refractive index layers
Implementation Method 2
can be integrated into standard manufacturing processes without heating the substrate
Data Source
AI summary
The invention relates to an optical lens comprising a substrate having a front main face and a rear main face, at least one main face of which being successively coated with a first high refractive index sheet which does not comprise any Ta2O5 layer, a second low refractive index sheet a third high refractive index sheet, a monolayer sub-layer having a thickness higher than or equal to 50 nm, and a multilayer interferential coating comprising a stack of at least one high refractive index layer and at least one low refractive index layer. The reflection performance on at least one main face is improved in scotopic conditions, fornear infrared light or for a wide range of angles of incidence.