Polarizing Plastic Lens Manufacturing with Downward Adhesive Columns
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Solution Overview
Problem
Existing methods for manufacturing polarizing lenses with embedded polarizing films face issues such as partial deformation and uneven adhesive application, leading to variations in the distance between the polarizing film and the lens surface, which compromises the quality and appearance of the polarizing plastic lens.
Innovation Solution
A method involving the use of a thixotropic curable adhesive, where adhesive columns are formed on the rim portion of the upper mold facing downward to prevent deformation and ensure consistent spacing, combined with a curing process that stabilizes the adhesive columns to maintain the gap between the mold and the polarizing film, and a heat treatment of the polarizing film to prevent astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is applied in column form on the molding surface of the mold, then bonding between the mold and polarizing film is achieved, but the adhesive may tilt or topple due to gravity and weight, causing the polarizing film to become skewed and compromising lens quality
Solution Approach 1:
The patent inverts the conventional approach by discharging the adhesive from beneath the molding surface of the upper mold rather than from above. This inversion allows the adhesive to be applied in a state where gravity acts downward, preventing the adhesive columns from tilting or toppling, thereby maintaining precise positioning of the polarizing film while achieving reliable bonding.
Solution Approach 2:
The patent employs a thixotropic curable adhesive that changes its viscosity parameters under different conditions. The adhesive exhibits high viscosity when discharged and maintained in column form, preventing deformation under gravity. Upon curing, the adhesive transitions to a solid state with different mechanical properties, ensuring stable bonding without compromising positioning precision.
2Productivity
If resin discharge and curing are conducted in parallel, then manufacturing efficiency is improved, but the polarizing film tends to partially deform and the needle tends to clog
Solution Approach 1:
The patent applies adhesive in advance on the molding surface before introducing the curable composition. This preliminary action ensures that the polarizing film is securely bonded and positioned before the casting and curing processes begin, preventing partial deformation during manufacturing while maintaining efficient production throughput.
3Reliability
If adhesive columns are formed facing upward, then bonding is achieved, but the adhesive columns deform under gravity making it difficult to control the gap between the mold and polarizing film
Solution Approach 1:
The patent inverts the adhesive application direction, discharging adhesive from beneath the molding surface so that adhesive columns form facing downward. This inversion aligns the adhesive column orientation with the direction of gravity, preventing deformation and enabling precise control of the gap between the mold and polarizing film while maintaining effective bonding.
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 ensures precise control of the gap between the mold and the polarizing film, maintaining the adhesive columns' shape and preventing deformation, resulting in a polarizing plastic lens with improved external appearance and reduced astigmatism.
Implementation Method 1
discharging a thixotropic curable adhesive from a discharge nozzle positioned beneath the molding surface of the upper mold to form adhesive columns
Implementation Method 2
polymerizing and curing the curable composition that has been cast to provide a polarizing plastic lens
Data Source
AI summary
Method of manufacturing polarizing plastic lens, including an upper mold positioning step of positioning an upper mold so that a nonmolding surface faces up and a molding surface faces down, an adhesive column forming step of discharging a thixotropic curable adhesive from a nozzle beneath the upper mold to form adhesive columns on the molding surface of the upper mold, a step of bonding the upper mold and a polarizing film, an adhesive column curing step of subjecting the adhesive columns to a curing treatment, a casting mold assembling step of assembling a casting mold having a cavity within which the polarizing film has been positioned with the upper mold to which the polarizing film has been bonded, a lower mold positioned opposite the upper mold so as to sandwich the polarizing film, and a sealing member maintaining a spacing between the upper mold and lower mold, and a polymerizing and curing step of casting a curable composition into the cavity, and polymerizing and curing the curable composition that has been cast to provide a polarizing plastic lens within which the polarizing film is positioned.