Contact Lens Mold Tabs for Edge Height Control
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Solution Overview
Problem
Existing contact lens molds struggle to control edge height and allow free flow of excess monomer, leading to monomer entrapment and difficulties in producing lenses with consistently rounded edges.
Innovation Solution
The molds incorporate tabs on one mold half for centering and spacing, enabling precise control of edge height and allowing unimpeded flow of excess monomer, composed of thermoplastic polymers that allow UV polymerization and are suitable for producing lenses with rounded edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If known lens molds are used to produce lenses with rounded edges, then the lens edges are rounded and avoid impingement on the conjunctival membrane, but the edge height cannot be controlled adequately and monomer flow is interrupted causing entrapment
Solution Approach 1:
A fluid communication channel is introduced as an intermediary pathway between the mold cavity and the exterior. This channel allows excess monomer to escape while the meniscus interface controls the rounding process, resolving the contradiction between achieving rounded edges and maintaining edge height control
Solution Approach 2:
The mold is segmented into functional zones: a rounded edge forming zone that shapes the lens edge, and a fluid communication channel that separately handles monomer evacuation. This segmentation allows each zone to optimize its function without interfering with the other
2Shape
If known lens molds are used to produce lenses with rounded edges, then the lens edges are rounded, but monomer flow is interrupted producing monomer surrounding the lens that is difficult to remove
Solution Approach 1:
The fluid communication channel serves as an intermediary escape route for excess monomer, allowing it to leave the mold cavity systematically rather than being trapped around the lens. This resolves the contradiction between forming rounded edges and enabling easy monomer removal
Solution Approach 2:
The mold design preliminarily establishes escape pathways for monomer before the molding process completes. By pre-configuring the fluid communication channel, the system prevents monomer entrapment from occurring in the first place, making removal easier
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 ensures accurate edge height control and easy removal of excess monomer, resulting in contact lenses with rounded edges of optical quality and improved manufacturing efficiency.
Implementation Method 1
preferably one that is sufficiently transparent to ultra-violet light to allow irradiation therethrough to promote polymerization
Implementation Method 2
sufficiently transparent to ultra-violet light to allow irradiation therethrough to promote polymerization
Data Source
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AI summary
The present invention provides molds (102, 103) useful in contact lens production, which molds incorporate a centering and spacing feature in the form of tabs (116) on one of the mold halves. The spacing feature both centers the mold halves in relationship to each other and permits free flow of excess monomer from the mold. Additionally, the spacing feature aids in height control of the one mold half in relation to the other mold half.