Spectacle Lens Overmoulding for Complex Geometries
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Solution Overview
Problem
Existing methods for manufacturing spectacle lenses struggle to combine optical properties with decorative or functional aspects while simplifying the machining process to achieve complex structures and ensure optimal adhesion of coatings and overmoulded materials.
Innovation Solution
A method involving the use of a lens blank made from injection-molded or cast plastic, where material is removed and modified to enhance adhesion, followed by overmoulding to create complex shapes and profiles, allowing for the integration of different materials and coatings to achieve desired optical and aesthetic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If material is removed from the lens blank to create complex shapes and profiles, then the lens can achieve decorative and functional aspects, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by creating a mold cavity that pre-forms the complex shape and profile of the lens before final assembly. The mold cavity is designed with the desired complex geometry, allowing the lens material to be shaped into the final decorative and functional form during the molding process itself, rather than requiring subsequent complex machining or assembly steps.
Solution Approach 2:
The patent merges the lens blank formation and shape creation into a single integrated molding process. By combining the formation of the lens substrate and the creation of complex surfaces into one operation, the patent reduces the number of separate manufacturing steps while achieving the desired decorative and functional aspects.
2Adaptability or versatility
If multiple coatings are applied to the lens to enhance optical and aesthetic properties, then the lens functionality improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent combines multiple coating applications into a single integrated step during the molding process. The mold cavity is designed to receive and accommodate multiple coating layers simultaneously, allowing different optical and aesthetic coatings to be applied in one operation rather than requiring separate sequential steps.
Solution Approach 2:
The patent employs a universal coating application method that can accommodate multiple different coating types (optical, aesthetic, protective) within a single process step. The mold cavity design allows various coating materials to be applied together, making the manufacturing process multi-functional while reducing overall complexity.
3Ease of manufacture
If the lens structure is simplified to reduce machining requirements, then manufacturing cost decreases, but the ability to achieve complex geometries is limited
Solution Approach 1:
The patent applies preliminary action by pre-forming the complex geometry within the mold cavity before the lens material is fully shaped. This allows the lens to achieve complex shapes without requiring extensive post-machining, as the fundamental geometry is established during the initial molding process.
Solution Approach 2:
The patent replaces mechanical machining operations with a molding-based formation process. Instead of using mechanical tools to cut and shape the lens into complex forms, the patent uses a mold cavity to define the geometry, substituting mechanical removal of material with a forming process that creates the shape directly.
4Strength
If adhesion promoters are applied to the lens surface to ensure optimal bonding, then the bonding strength improves, but the manufacturing steps increase
Solution Approach 1:
The patent merges the adhesion promoter application with other coating steps in the manufacturing process. The mold cavity is designed to accommodate adhesion promoters alongside other coatings, allowing multiple functions (adhesion enhancement, optical properties, aesthetic finishes) to be achieved in a single integrated process step rather than requiring separate adhesion promotion steps.
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 enables the production of lenses with enhanced adhesion and complex geometries, reducing production costs and defects, while maintaining optical quality and allowing for a wide range of aesthetic and functional features.
Implementation Method 1
The lens blank is made by a process of injecting or casting plastic material into a suitable mould
Implementation Method 2
provision is made to produce the final lens structure from the lens blank by cutting
Implementation Method 3
followed by overmoulding to create complex shapes and profiles, allowing for the integration of different materials
Data Source
AI summary
What is described is a method of manufacturing a lens (2) for spectacles, comprising the steps of providing a lens blank (1) made from plastic material, obtaining, by cutting the blank (1), a corresponding lens having a final shape and profile suitable for mounting in a mounting frame, removing material from the lens (2) in predetermined areas of the lens to produce a first lens portion (3), inserting the first lens portion (3) into a mould (4) for overmoulding, injecting material into the mould (4) to produce at least a second lens portion (5) overmoulded on the first lens portion (3), and removing the lens (2), in which the first and second lens portions (3, 5) are integrated with one another, from the mould (4).