Optimized Semi-Finished Lens Blank for Direct Surfacing
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Solution Overview
Problem
Optical labs face challenges in increasing the throughput of existing direct surfacing machinery used in free-form lens manufacturing, due to the high cost and limited production of sophisticated digital surfacing equipment.
Innovation Solution
The development of semi-finished ophthalmic lens blanks with optimized front and back optical surfaces, and edge shapes that approximate the maximum thickness and dimensions of finished lenses, allowing for reduced material removal and improved processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If free-form manufacturing techniques are used to allow customization and reduce inventory, then lens manufacturing flexibility and inventory carry are improved, but throughput of existing direct surfacing machinery is limited due to high equipment cost and sophisticated nature
Solution Approach 1:
The patent applies preliminary action by pre-forming the lens blank with an optimized front surface curvature and edge shape that approximates the final lens geometry. This preliminary shaping reduces the amount of material removal and generator movement required during direct surfacing, thereby increasing throughput without sacrificing customization capability.
Solution Approach 2:
The patent changes the geometric parameters of the lens blank, specifically optimizing the front surface curvature radius and edge shape to match the expected final lens dimensions. This parameter optimization minimizes processing time and material removal during surfacing operations.
2Ease of manufacture
If conventional semi-finished lens blanks with spherical surfaces are used, then manufacturing process is simple, but significant material removal and polishing time are required
Solution Approach 1:
The lens blank is pre-formed with an optimized front surface curvature that matches the expected final lens geometry more closely than conventional spherical blanks. This preliminary action reduces the polishing time required to achieve the final surface finish while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies local quality by optimizing specific regions of the lens blank, particularly the front surface curvature and edge shape, to match the expected final lens geometry. This localized optimization reduces material removal in critical areas while maintaining overall manufacturing simplicity.
3Productivity
If optimized lens blanks with approximated final geometry are used, then material removal is reduced and throughput increases, but more sophisticated blank manufacturing is required
Solution Approach 1:
The lens blank is pre-formed with optimized geometry through molding or casting processes. This preliminary action creates a blank that closely approximates the final lens shape, reducing subsequent processing requirements and increasing throughput without requiring overly complex manufacturing equipment.
Solution Approach 2:
The patent optimizes specific geometric parameters of the lens blank, such as front surface curvature radius and edge shape dimensions, to match expected final lens geometry. These parameter changes are achieved through controlled molding or casting processes that balance complexity with productivity gains.
Data Source
AI summary
A semi-finished ophthalmic lens for formation of a plurality of different finished ophthalmic lenses requiring reduced amounts of lens material to be removed for formation of the finished ophthalmic lenses and reduced rates of departure of a surfacing tool and methods of making same. Lens material is reduced by providing first and second surfaces that have different optical powers, the second optical surface having a second curve that approximates second optical surfaces of a plurality of finished ophthalmic lenses at coordinates at which lenses of the plurality of finished ophthalmic lenses have maximum thicknesses.