Anti-Reflective Coating Adhesion on Plastic Lenses
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Solution Overview
Problem
Current methods for applying anti-reflective (AR) coatings to plastic ophthalmic lenses face challenges with adhesion, particularly when using vacuum deposition, which can lead to peeling or scratching, and require high temperatures that distort optical surfaces, making on-site manufacturing impractical.
Innovation Solution
The use of dipodal silanes in super hydrophobic coatings on the lens mold, combined with a cyclic azasilane coupling agent, to promote adhesion of the AR coating without the need for high temperatures, allowing for on-site manufacturing of AR-coated plastic ophthalmic lenses with improved stability and adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum vapor deposition is used to apply AR coating, then the AR coating can be applied to the lens, but adhesion is problematic resulting in peeling or scratching
Solution Approach 1:
A coupling agent layer is introduced as an intermediary between the inorganic AR coating and the organic plastic lens substrate. This coupling agent contains both inorganic binding sites (for bonding to the AR coating) and organic functional groups (for bonding to the plastic), thereby mediating the adhesion between incompatible materials and preventing peeling or scratching.
Solution Approach 2:
The coupling agent is itself a composite material with dual functionality - it contains both inorganic components (such as silanes that bond to metal oxides in the AR coating) and organic components (that bond to the plastic lens material). This composite structure enables it to bridge the inorganic-organic interface and improve adhesion.
2Ease of manufacture
If high temperature processes are used to apply AR coating, then the coating can be applied, but the optical surface of the mold is distorted
Solution Approach 1:
The coupling agent application process uses room temperature or low temperature conditions instead of high temperature processes. The coupling agent is applied in solution form and cured at temperatures that do not distort the optical mold surfaces, thereby maintaining manufacturing precision while still enabling effective adhesion promotion.
3Ease of manufacture
If AR coating is applied via vacuum deposition, then the coating can be applied, but additional shipping time and expense are required
Solution Approach 1:
The coupling agent application step is extracted from the traditional vacuum deposition process and performed separately at room temperature before AR coating application. This extraction enables the preparation work to be done on-site without requiring specialized vacuum deposition equipment or shipping the lenses to external facilities, thereby reducing shipping time and enabling on-site manufacturing.
4Reliability
If conventional AR coating methods are used, then the coating can be applied, but organic plastic lens material and inorganic AR material do not readily adhere
Solution Approach 1:
The coupling agent serves as a mediator between the organic plastic lens material and the inorganic AR coating material. It contains functional groups that are compatible with both material types - organic functional groups that bond to the plastic and inorganic binding sites that bond to the metal oxides in the AR coating, thereby enabling adhesion between otherwise incompatible materials.
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
This method enables the stable application of AR coatings with enhanced adhesion to plastic lenses, facilitating on-site manufacturing and reducing the risk of peeling or scratching, while avoiding the distortion associated with high-temperature processes.
Implementation Method 1
dipodal silanes in super hydrophobic coatings on the lens mold, combined with a cyclic azasilane coupling agent, to promote adhesion of the AR coating
Implementation Method 2
cyclic azasilane coupling agent, to promote adhesion of the AR coating
Implementation Method 3
dipodal silanes in super hydrophobic coatings on the lens mold
Data Source
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AI summary
The present invention relates to a method of applying an anti-reflective coating to an optical surface of a mold. In one embodiment, the method includes the steps of: providing a lens mold having an optical surface; forming a layer of a super hydrophobic material with a thickness of about 30 to 40 nm over the optical surface, wherein the super hydrophobic material contains dipodal silane; forming an anti-reflective coating layered structure over the layer of the super hydrophobic material; and forming a layer of a cyclic azasilane coupling agent that is deposited with a monolayer thickness to the anti-reflective coating layered structure using vapor deposition or by dip coating using a solution of cyclic azasilane coupling agent in an aprotic solvent.