Ophthalmic Lens Peripheral Curvature Modification
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Solution Overview
Problem
The manufacturing of high power and high prismatic lenses for eyeglasses often results in sharp, thin edges at the periphery of lens blanks, which can break during processing, damage equipment, and hinder automated manufacturing, leading to inefficiencies and bulkier lenses with cosmetic and physical discomfort for users.
Innovation Solution
A system employing digital surfacing techniques to create non-spherical surfaces on lens blanks, modifying the peripheral curvature to prevent sharp edges by matching the front and back surface curves, ensuring a thicker, rounded periphery that avoids edge issues and facilitates smooth manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional lathing and lapping methods are used to create high power lenses, then the optical prescription requirements are met, but sharp thin edges form at the periphery causing manufacturing problems
Solution Approach 1:
The patent applies different surface curvatures to different regions of the lens blank. The prescription portion maintains the required optical curvature, while the peripheral portion is modified to have a different curvature that prevents sharp edge formation. This local differentiation allows the lens to meet optical requirements in the prescription area while avoiding manufacturing problems in the peripheral area.
Solution Approach 2:
The lens blank surface is divided into two functional segments: the prescription portion that requires specific optical curvature for vision correction, and the peripheral portion that is modified to prevent sharp edge formation. By segmenting the surface treatment, the patent resolves the conflict between optical precision and manufacturing ease.
2Strength
If additional thickness is added to the lens to offset peripheral thinning, then edge strength is improved, but lens weight and cosmetic appearance deteriorate
Solution Approach 1:
Instead of uniformly increasing lens thickness, the patent applies local quality modification by changing only the peripheral surface curvature. This creates additional peripheral thickness locally where needed for edge strength, while maintaining the original lens thickness in the central prescription area, thereby avoiding increased weight and cosmetic issues.
3Manufacturing precision
If sharp edges are created during high power lens manufacturing, then optical prescription requirements are met, but equipment damage and manufacturing costs increase
Solution Approach 1:
The patent applies preliminary anti-action by modifying the peripheral surface curvature before the lens undergoes subsequent manufacturing processes. By preventing sharp edge formation in advance, the lens is protected from causing equipment damage during polishing, coating, and edging operations, thereby eliminating harmful effects before they can occur.
4Productivity
If automated manufacturing is implemented, then productivity increases, but sharp edges require manual inspection reducing automation
Solution Approach 1:
The patent applies preliminary action by pre-modifying the peripheral surface curvature to eliminate sharp edges before the lens enters automated manufacturing processes. This preliminary modification removes the need for manual inspection and intervention during subsequent automated processes, thereby maintaining high automation levels and productivity.
Data Source
AI summary
A system and method for manufacturing an ophthalmic lens is described. In some examples, the system applies a back surface to a lens blank that includes an aspherical curve having two radii of curvature. In some examples, a back surface of a peripheral portion of the lens follows the curvature of a front surface of the lens in order to establish a rounded, non-sharp edge to a lens blank used during the manufacturing process of a prescription eyeglass lens.