Multi-Material Contact Lens Package With Flexible Flange Interlock
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Solution Overview
Problem
Existing contact lens packaging materials, such as polypropylene, absorb additional components like wetting agents and pharmaceuticals, leading to reduced efficacy, and structural interlocks break under flexural stress, necessitating improved packaging solutions that utilize different materials for the bowl and flange without bonding issues.
Innovation Solution
A contact lens package design using a bowl and flange made from different polymer materials, with a mechanical interlock at their interface, allowing for a range of materials that are inert to the lens and solution, and providing strength against flexural stress during opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common packaging plastics like polypropylene are used for the bowl, then manufacturing cost is reduced and ease of manufacture is improved, but the plastic absorbs additional components like wetting agents and pharmaceuticals, reducing product efficacy
Solution Approach 1:
The package base is divided into two separate components: a bowl made from non-absorbent material (cyclic olefin polymer or copolymer) that contacts the lens and solution, and a flange made from different materials (including recycled or colored materials) that provides structural support. This segmentation allows each part to be optimized for its specific function without compromise.
Solution Approach 2:
Different regions of the package base have different material properties tailored to their specific requirements. The bowl region uses non-absorbent material to prevent component absorption, while the flange region can use cost-effective or environmentally sustainable materials for structural support and sealing functions.
2Strength
If structural interlocks are used to join dissimilar materials, then interlock strength against lateral pull force is improved, but the interlocks break under flexural stress during package opening
Solution Approach 1:
The interlock design incorporates flexibility to accommodate the dynamic stresses of package opening. The flange material and interlock geometry are designed to flex during the peeling action without breaking, while still maintaining strength against lateral pull forces during normal use and sterilization.
Solution Approach 2:
The package base uses composite construction with a bowl made from cyclic olefin polymer or copolymer and a flange made from different materials. The interface between these dissimilar materials is designed with specific interlock features that accommodate material property differences while maintaining structural integrity under various stress conditions.
3Adaptability or versatility
If recycled or colored materials are used for the bowl, then environmental sustainability is improved or packaging distinctiveness is enhanced, but the materials interact with the contact lens solution or lens, compromising sterility and product integrity
Solution Approach 1:
The package is segmented so that only the bowl portion (which contacts the lens and solution) is made from non-absorbent, inert materials. The flange can be made from recycled or colored materials that provide environmental benefits or branding value, eliminating the need to compromise material safety for sustainability goals.
Solution Approach 2:
Material selection is optimized for each specific region: the bowl uses high-purity, non-absorbent cyclic olefin polymer or copolymer to prevent interaction with lens components, while the flange can use more versatile materials including recycled content or colored variants for structural and aesthetic purposes.
Data Source
AI summary
There is described a contact lens package containing a bowl for holding a contact lens and a flange around the bowl which may be made from a different polymer material than the bowl. The packages comprise at least one interface tab with at least one slot so that the second polymer material forming the flange can encapsulate the tab providing a mechanical interlock displaying good flexural strength.