Optical Lens Interferential Coating 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 without compromising adhesion to the substrate or increasing the risk of delamination.
Innovation Solution
A specific combination of layers is used, including a thick sub-layer and a multilayer interferential coating with a high refractive index and low refractive index layers, deposited without additional gas supply to enhance abrasion resistance and adhesion, and the layers are optimized to maintain optical performance and withstand temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a relatively thick sub-layer below the anti-reflection coating is used to improve abrasion resistance, then abrasion resistance is improved, but the risk of delamination increases and adhesion to substrate deteriorates
Solution Approach 1:
The coating system is divided into distinct functional segments: a thin adhesion promoter layer (5-20 nm) directly on the substrate, followed by the thick protective sub-layer (100-500 nm), then the interferential coating layers. This segmentation allows the thin promoter layer to ensure adhesion while the thick sub-layer provides abrasion resistance, resolving the contradiction between protection and bonding.
Solution Approach 2:
An adhesion promoter layer composed of specific metal oxides (TiO2, ZrO2, or Nb2O5) is introduced as an intermediary between the substrate and the thick sub-layer. This intermediate layer acts as a chemical bridge, forming strong bonds with both the substrate and the overlying protective layers, thereby enabling the use of thick sub-layers for abrasion resistance without compromising adhesion.
2Strength
If ion assistance is used during vapor deposition to increase compressive stress and improve hardness, then abrasion resistance is improved, but delamination risk increases
Solution Approach 1:
The deposition parameters are precisely controlled: ion assistance is applied only to specific layers (adhesion promoter and selected interferential layers) at optimized flux ratios and energies, rather than uniformly to all layers. The sub-layer is deposited without ion assistance or with minimal ion assistance, maintaining low stress. This selective parameter adjustment achieves hardness improvement where needed while preventing delamination in stress-sensitive layers.
3Manufacturing precision
If the total thickness of anti-reflection coating is increased to improve optical performance, then optical performance is improved, but manufacturing complexity and production time increase
Solution Approach 1:
The optical coating system uses composite material architecture combining different metal oxide layers (TiO2, ZrO2, Nb2O5, SiO2) with distinct functional properties. Each material is selected for its specific refractive index, mechanical properties, and deposition characteristics, allowing optimized optical performance with controlled total thickness and reduced manufacturing complexity compared to uniform multi-layer systems.
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 enhanced abrasion resistance and thermal stability with improved adhesion, maintaining optical performance and preventing delamination, thus offering a durable and reliable optical article.
Implementation Method 1
a multilayer interferential coating comprising a stack of at least one high refractive index layer having a refractive index higher than 1.55 and at least one low refractive index layer having a refractive index of 1.55 or less
Implementation Method 2
deposited by ion-assisted vapor deposition
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 100 nm, a multilayer interferential coating comprising a stack of at least one high refractive index layer and at least one low refractive index layer, and a filtering interferential system that selectively reflects or transmits visible light in a narrow range of wavelengths.