Plastic Lens Coating Adhesion via Segmented Thermal Processing
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Solution Overview
Problem
The challenge in manufacturing plastic lenses is achieving both strong adhesion between the coating film and the substrate and optimal optical characteristics, as heat treatment to remove distortion in the substrate can lead to deformation and reduced adhesion, while treating the coating film separately may not effectively eliminate distortion within the film.
Innovation Solution
A method involving heating the plastic lens substrate to a temperature above its glass transition temperature before coating, forming a cured film through photopolymerization, and then conducting a heat treatment at a temperature below the substrate's glass transition but above the film's, ensuring both substrate and film distortion are addressed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heat treatment is conducted at a temperature greater than or equal to the glass transition temperature of the substrate after coating the coating film, then distortion within the substrate is removed, but adhesion between the coating film and substrate decreases due to substrate deformation
Solution Approach 1:
The heat treatment process is segmented into two distinct stages: first heating the substrate alone to remove distortion, then heating the coated lens at a lower temperature to remove coating film distortion. This segmentation allows each component to be treated at its optimal temperature without causing adhesion problems.
Solution Approach 2:
The invention changes the temperature parameter of heat treatment based on what is being treated. When treating only the substrate, temperature is set to Tg or higher. When treating the coated lens, temperature is set to a lower range (50-100°C) that is sufficient for the coating film but below the substrate's Tg, preventing substrate deformation while still removing coating distortion.
2Strength
If heat treatment temperature is set lower than the glass transition temperature of the lens substrate, then adhesion is maintained, but it becomes difficult to effectively eliminate distortion within the lens substrate
Solution Approach 1:
The substrate distortion removal is performed as a preliminary action before coating the film. By heating the substrate to Tg or higher and removing its distortion first, the subsequent coating process and final heat treatment can focus on the coating film without being constrained by substrate distortion limitations.
3Strength
If the coating film has suitable fluidity to track substrate deformation, then adhesion is ensured, but it becomes difficult to control the surface dioptric power of the lens because the shape of the lens surface changes greatly
Solution Approach 1:
The invention applies preliminary anti-action by removing substrate distortion through heat treatment before coating the film. This prevents the substrate from deforming during subsequent coating and heat treatment processes, thereby maintaining control over the lens surface shape and dioptric power while still allowing the coating film to adhere properly.
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 approach results in a high-quality plastic lens with improved adhesion and optical characteristics by effectively eliminating distortion in both the substrate and the coating film, maintaining the lens's shape and optical integrity.
Implementation Method 1
forming a cured film by irradiating the photocurable composition that has been coated on the substrate with light to cure at least a portion of the composition
Implementation Method 2
heating the plastic lens substrate to a temperature greater than or equal to a glass transition temperature of the substrate
Implementation Method 3
conducting a heat treatment of the plastic lens on which the cured film has been formed at a temperature, the temperature being lower than the glass transition temperature of the substrate but greater than or equal to a glass transition temperature of the cured film
Data Source
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AI summary
The present invention relates to a method of manufacturing a plastic lens comprising a cured film on at least one of a pair of opposing surfaces of a plastic lens substrate. The method of manufacturing a plastic lens of the present invention comprises heating the plastic lens substrate to a temperature greater than or equal to a glass transition temperature of the substrate; coating a photocurable composition on at least one of a pair of opposing surfaces of the lens substrate following the heating; forming a cured film by irradiating the photocurable composition that has been coated on the substrate with light to cure at least a portion of the composition; and conducting a heat treatment of the plastic lens on which the cured film has been formed at a temperature, the temperature being lower than the glass transition temperature of the substrate but greater than or equal to a glass transition temperature of the cured film.