Ophthalmic Lens Wafer Coating for Insert-Resin Adhesion
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Solution Overview
Problem
Existing polyurea-urethane ophthalmic lenses face adhesion issues between the functional insert and the resin, leading to potential separation during processing and usage, which can result in lens failure.
Innovation Solution
The use of an aliphatic polycarbonate polyurethane dispersion or polysiloxane as a wafer treatment to improve adhesion between the functional insert and the polymerized polyurea-urethane lens resin, combined with a mixture of aliphatic diisocyanate and dual amine/hydroxyl-functional components in the resin composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a functional insert is incorporated into a polyurea-urethane lens, then the lens gains additional functionality (photochromic or polarization), but adhesion between the insert and resin deteriorates, leading to separation during processing and usage
Solution Approach 1:
A primer layer comprising a polyol and a catalyst is applied to the functional insert before embedding it in the polyurea-urethane resin. This primer layer acts as an intermediary between the insert and the resin, promoting chemical bonding and preventing separation during processing and usage.
Solution Approach 2:
The invention changes the chemical parameters of the interface between the functional insert and the resin by introducing a primer layer with specific chemical composition (polyol and catalyst). This chemical modification enables strong adhesion without compromising the functional properties of the insert.
2Ease of manufacture
If conventional casting methods are used with functional inserts, then manufacturing simplicity is maintained, but lens failure occurs due to separation during surfacing and edging
Solution Approach 1:
The primer layer is applied to the functional insert before the casting process. This preliminary action ensures that the adhesion problem is addressed in advance, allowing the subsequent surfacing and edging operations to proceed without separation or lens failure.
3Device complexity
If no wafer treatment is applied, then the manufacturing process remains simple, but the lens resin separates from the functional insert during usage
Solution Approach 1:
The primer layer serves as a chemical mediator that creates strong bonding between the functional insert and the polyurea-urethane resin. This additional layer, while adding a step to the process, ensures long-term durability and prevents separation during usage.
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
Enhances the adhesion between the functional insert and the lens resin, preventing separation during processing and usage, resulting in a robust and durable ophthalmic lens.
Implementation Method 1
a non-tacky wafer treatment comprising an aliphatic polycarbonate polyurethane dispersion or a polysiloxane adhering the optically functional wafer to the layer of the polymerized polyurea-urethane lens resin
Implementation Method 2
a polymerized polyurea-urethane lens resin comprising a mixture of an aliphatic diisocyanate component and a dual amine/hydroxyl functional containing component and/or a hydroxyl-containing component
Data Source
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AI summary
An ophthalmic lens incorporating an optically functional wafer having improved adhesion to a polymerized polyurea-urethane bulk lens resin.