Polarizing Lens Composite Structure for Durability
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Solution Overview
Problem
Existing polarizing lenses face limitations in durability and material choice due to the use of birefringent and stretched polycarbonate layers, restricting their application and performance.
Innovation Solution
A polarizing lens structure comprising a thermoplastic polycarbonate mechanical support layer, an intermediate polyvinyl alcohol layer, and an outer cellulose triacetate layer, produced through a process involving differentiated heating and thermoforming of a laminated film, followed by injection of polycarbonate to fuse with the thermoplastic polycarbonate, enhancing mechanical and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If birefringent polycarbonate and stretched polycarbonate layers are used in polarizing lenses, then the polarizing effect is achieved, but the durability and resistance to external attacks are reduced
Solution Approach 1:
The patent employs a composite structure consisting of multiple layers: a polycarbonate layer providing mechanical strength, a PVA layer with dichroic dyes for polarizing functionality, and a cellulose triacetate outer layer for chemical resistance. This composite approach allows each material to contribute its superior properties, resolving the contradiction between durability and material versatility by combining rather than compromising materials.
2Reliability
If a laminated film structure with multiple layers is used, then durability and chemical resistance are improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-heating the laminated film to different temperatures for each layer before thermoforming. This preparatory step facilitates the subsequent forming process by making the materials more pliable and easier to mold, thereby reducing the overall manufacturing complexity despite the multi-layer structure.
Solution Approach 2:
The patent utilizes parameter changes by applying differentiated heating temperatures to different layers of the laminated film during manufacturing. This allows each material layer to be optimized for its specific properties while facilitating the thermoforming process, managing the complexity through controlled parameter variation rather than uniform treatment.
3Manufacturing precision
If differentiated heating and thermoforming are applied to laminated film, then lens quality and material properties are optimized, but the manufacturing time and process steps increase
Solution Approach 1:
The patent applies local quality by differentiating the heating treatment for each layer of the laminated film according to its specific material properties. The polycarbonate, PVA, and cellulose triacetate layers are heated to different temperatures to optimize their respective contributions to lens quality, rather than applying a uniform heating process that would compromise some layers.
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
The solution provides lenses with improved durability and resistance to external attacks, offering a more versatile and high-quality alternative by combining the properties of polycarbonate and cellulose triacetate, while allowing for controlled thermoforming and injection processes that optimize lens quality.
Implementation Method 1
a layer of mechanical support comprising a thermoplastic polymer polycarbonate
Implementation Method 2
a polarizing filter generally made in the form of a film of polyvinyl alcohol polymer (or PVA)... incorporating molecules of dichroic dyes and/or dichroic iodine crystals... exhibits a privileged absorption of visible electromagnetic radiation for a particular spatial orientation
Implementation Method 3
the outer layer of cellulose triacetate providing resistance to chemical interactions
Implementation Method 4
preheating a laminated film comprising an outer layer of cellulose triacetate (TAC), an intermediate layer of polyvinyl alcohol (PVA) and an outer layer of polycarbonate (PC), with different temperatures for the outer layers of the laminated film, thermoforming the laminated film by carrying out differentiated heating of the outer layers
Implementation Method 5
injecting polycarbonate into the mold in such a way that the polycarbonate layer fuses with the injected polycarbonate to form the mechanical support layer of the lens
Data Source
Figure 1
AI summary
The invention relates to a method for producing a lens, comprising the following steps consisting in: pre-heating a laminated film comprising an outer TAC layer (3), an intermediate PVA layer (2) and an outer PC layer (1), using different temperatures for the outer layers; thermoforming the laminated film, comprising the differentiated heating of the outer films; disposing the thermoformed film in a mould in the shape of the lens; and injecting PC into the mould, such that the polycarbonate layer (1.1) fuses with the injected PC (1.2) in order to form the mechanical supporting layer of the lens. The invention also relates to the resulting lens.