Solution Casting Optical Film for Eyeglass Lenses
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Solution Overview
Problem
Traditional methods for manufacturing IR and visible light-blocking lenses, such as extrusion and injection molding, face challenges including uneven coating due to lens curvature, dye degradation from heat, susceptibility to scratches and chemicals, aesthetic issues, and increased costs, which affect the effectiveness and comfort of eyewear.
Innovation Solution
A solution casting method is employed, where a polymer solution is applied to a moving belt and solidified using air flow, allowing for precise control of thickness and absorption, and then laminated onto lenses without excessive heat, enabling the creation of thin, effective IR and visible light-blocking films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional extrusion or injection molding methods are used to add IR or visible dyes during the manufacturing process, then the lenses can be produced with protective coating, but heat is used to soften the plastic which causes dye degradation and reduces eye protection effectiveness
Solution Approach 1:
The patent applies preliminary action by pre-mixing the IR or visible dyes into the plastic material before the molding process, so that the dyes are already incorporated into the lens substrate before any heat treatment occurs. This eliminates the need for subsequent high-temperature dyeing processes that would degrade the dyes, while still achieving uniform distribution of the protective dye throughout the lens.
2Reliability
If IR or visible coating is applied by dipping or spraying solvent dyes on another optical layer, then the lenses can be protected from harmful rays, but the curvature of most lenses causes uneven coating application which reduces protection effectiveness
Solution Approach 1:
The patent merges the lens substrate and the protective dye coating into a single integrated structure by incorporating the dyes directly into the plastic material during molding. This eliminates the separate coating step that causes uniformity problems on curved surfaces, while still providing comprehensive eye protection through the uniformly distributed dye throughout the entire lens.
3Strength
If multiple protection layers are sprayed or dipped on top of the IR/visible layer to prevent scratches and chemical damage, then the lenses gain improved durability, but the lens becomes thicker which creates design and comfort barriers
Solution Approach 1:
The patent creates a composite material structure by integrating multiple functional dyes (IR-blocking dyes and visible light dyes) into a single plastic matrix. This composite approach provides both UV/IR protection and visible light filtering in one unified layer, eliminating the need for multiple separate protective coatings that would increase lens thickness, while maintaining comprehensive protection against scratches and chemical damage.
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 produces a virtually isotropic, dimensionally stable film with maximum optical purity and low haze, reducing the need for multiple layers and process time, while maintaining cost-effectiveness and enhancing visual comfort by effectively blocking harmful radiation.
Implementation Method 1
solidified using air flow
Implementation Method 2
absorb or reflect light of certain frequencies, e.g., IR frequencies
Implementation Method 3
absorb or reflect light of certain frequencies
Data Source
AI summary
Methods and apparatus are provided for eyeglass lens made using a solution casting process. The method may include providing a first soluble polymer solution. The method may include providing a first dye solution including at least one dye. The method may include adding the first dye solution to the first soluble polymer solution to form a first dyed solution. The method may include casting the first dyed solution to form a first film. The method may include providing a second soluble polymer solution. The method may include providing a second dye solution comprising at least one dye. The method may include adding the second dye solution to the second soluble polymer solution to form a second dyed solution. The method may include casting the second dyed solution onto the first film to form a two-layer film. The method may include laminating or casting the two-layer film to the eyeglass lens.