Contact Lens Surface Modification via Plasma
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Solution Overview
Problem
Contact lenses often suffer from either hydrophobicity, leading to discomfort due to dryness and irritation, or excessive hydrophilicity, causing them to float away from the cornea, necessitating improved wetability for patient comfort.
Innovation Solution
A method involving plasma treatment to generate free radicals on the contact lens surface, followed by reaction with organic compounds and subsequent oxidation to form a hydrophilic layer, reducing the contact angle with water to less than 50°, enhancing wetability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact lens surface is made highly hydrophilic to improve wetability and comfort, then the lens surface becomes too wet and floats above the cornea, causing discomfort
Solution Approach 1:
The patent applies plasma treatment to modify the surface energy and chemical composition of the contact lens, changing its hydrophilicity parameter to an optimal range. This controlled parameter change enables the lens to maintain appropriate wetability for comfort while preventing excessive floating, resolving the contradiction between hydrophilicity and wearability.
2Ease of operation
If the contact lens surface is made hydrophobic to reduce floating, then the lens surface becomes dry and rubs against the cornea, creating discomfort
Solution Approach 1:
The patent uses plasma treatment to adjust the surface hydrophobicity parameter, transforming it from a hydrophobic state to an optimally hydrophilic state. This parameter modification enables the lens to maintain sufficient wetability for comfort while avoiding excessive floating, effectively resolving the contradiction.
3Reliability
If plasma treatment is applied to increase hydrophilicity, then the contact angle with water is reduced to less than 50°, but the process complexity increases
Solution Approach 1:
The patent replaces complex multi-step chemical coating processes with plasma treatment, a physical/chemical field-based method. This substitution simplifies the overall process while achieving the desired hydrophilicity (contact angle < 50°), resolving the contradiction between performance improvement and process complexity.
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
Significantly improves the affinity of contact lenses for water, reducing discomfort by creating a lubricating layer and maintaining hydrophilicity even after simulated wear, ensuring long-lasting comfort and effective interaction with tears.
Implementation Method 1
exposing a polymer substrate to a first plasma under conditions selected to generate free radicals on a surface of the polymer substrate
Implementation Method 2
exposing the organic coating to a second plasma under conditions selected to oxidize the organic coating to thereby form a hydrophilic layer at the substrate surface
Data Source
AI summary
A method of increasing the hydrophilicity of a polymer surface, such as a contact lens surface, includes exposing the polymer substrate to a first plasma under conditions selected to generate free radicals on the surface of the polymer substrate. The method also includes reacting an organic compound with the free radicals on the surface of the polymer substrate to thereby form an organic coating. The method further includes exposing the organic coating to a second plasma under conditions selected to oxidize the organic coating to thereby form a hydrophilic layer at the substrate surface. The hydrophilic layer can have a contact angle with respect to water that is less than about 50°.