Ophthalmic Lens Insert Positioning via Molding Reference
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Solution Overview
Problem
Existing processes for manufacturing ophthalmic lenses with inserts, such as waveguides, face challenges in achieving precise positioning of the insert within the lens, which is critical for optical performance and assembly tolerances. This precision is difficult to maintain with simple tools, leading to issues with component breakage and the inability to achieve mass production due to high mold production costs.
Innovation Solution
A process that involves molding a lens blank with an insert positioned relative to a mechanical reference, allowing for precise machining of the lens faces based on the identified position of the insert. This process uses elements like independent parts or edges of the insert as positional references, enabling precise alignment and machining without the need for highly specialized molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the waveguide is adhesively bonded to the pad with high positional precision using strict parallelism and alignment tolerances, then the optical specifications are met, but the manufacturing cost increases due to complex molds and adhesive bonding processes
Solution Approach 1:
The waveguide is positioned and fixed to the pad before the molding process begins. The pad is pre-formed with the waveguide attached, and this assembly is then molded into the final lens structure. This preliminary positioning ensures precise alignment without requiring complex molds with tight tolerances, as the precision is established before molding rather than during it.
Solution Approach 2:
A pad serves as an intermediary element between the waveguide and the final lens structure. The waveguide is first bonded to the pad, and then the entire assembly is molded. The pad acts as a temporary carrier that simplifies the positioning process and protects the waveguide during subsequent machining operations.
2Manufacturing precision
If the waveguide is positioned precisely in the mold, then the optical specifications are met, but the risk of waveguide breakage during machining increases due to tool collision
Solution Approach 1:
The waveguide is positioned and secured to the pad before the molding and machining operations. By establishing the precise position in advance and protecting it during the molding process, the waveguide is less susceptible to displacement or breakage during subsequent machining operations.
Solution Approach 2:
The molding process itself acts as a protective cushioning step. The mold encases and protects the waveguide during the molding process, preventing tool collision. The waveguide is already in its final position before machining begins, and the molded structure provides physical protection during subsequent operations.
3Manufacturing precision
If complex molds with precise dimensional tolerances are used to position the waveguide, then the positioning accuracy is improved, but the production cost increases making mass production impossible
Solution Approach 1:
The waveguide is positioned and fixed to the pad before the molding process. This preliminary positioning step allows the use of simpler, less expensive molds that do not require precise dimensional tolerances built into the mold itself. The precision is achieved through the pre-assembly process rather than through expensive mold manufacturing, enabling mass production.
Solution Approach 2:
The pad serves as a temporary, disposable carrier that simplifies the molding process. Instead of creating expensive, precision-machined molds, a simpler pad structure is used that can be easily manufactured and discarded or reused. This approach significantly reduces tooling costs and enables mass production.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
The invention relates to a process for manufacturing an ophthalmic lens equipped with an insert (1), by means of a mold, comprising: - a step of molding a puck (3) comprising two faces (3A, 3B) and said insert (1) positioned between said faces; and - a step of machining at least one of said faces (3A, 3B) of said puck in order to form one of the front or back faces of said ophthalmic lens, the insert (1) being positioned relative to one portion of the mold before said molding step, According to the invention, an element associated with the insert or an imprint of this element left in the puck after the element has been removed comprises at least one of its portions providing a positional reference relative to said insert (1) in the machining step.