Spectacle Lens Edge Thickness Optimization
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Solution Overview
Problem
Conventional spectacle lenses face challenges in maintaining a homogeneous edge thickness after edging, leading to variations that affect optical power and aesthetic appearance, especially when fitted to non-symmetric frames, and often require supporting rims that reduce the usable optical area.
Innovation Solution
A computer-implemented method optimizes the geometrical profile and spatial variation of the refractive index of spectacle lenses to ensure an edge thickness variation of 0.5 mm or less, allowing for a homogeneous edge contour without a supporting rim, using additive manufacturing techniques to apply different materials selectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional homogeneous spectacle lenses are used, then manufacturing is simple, but edge thickness varies significantly affecting optical performance and aesthetics
Solution Approach 1:
The patent applies local quality by implementing a supporting rim with constant material thickness around the optical area. This rim structure provides localized structural support to maintain uniform edge thickness in the optical zone without requiring the entire lens to have complex variable thickness design, thus achieving manufacturing precision improvement with controlled complexity increase only in the rim region
Solution Approach 2:
The patent employs composite material structure by combining the optical area with the supporting rim made of the same or different material. The supporting rim acts as a structural component with constant thickness that compensates for edge thickness variations in the optical zone, achieving uniform edge thickness while maintaining optical performance
2Manufacturing precision
If lenticular lenses with supporting rim are used to achieve homogeneous edge thickness, then edge thickness uniformity improves, but usable optical area decreases
Solution Approach 1:
The patent segments the lens into two functional zones: the optical area for vision correction and the supporting rim for structural support. By separating these functions into distinct zones, the optical area can be maximized while the rim provides the necessary structural support for edge thickness uniformity, thus resolving the trade-off between optical area and edge thickness control
3Adaptability or versatility
If spectacle lenses are edged to fit non-symmetric frames, then adaptability to different frames improves, but edge thickness variation increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the supporting rim with constant thickness during lens manufacturing, before the edging process. This pre-established structural foundation allows the lens to be subsequently edged to fit various frame shapes without compromising edge thickness uniformity, thus enabling frame adaptability while maintaining manufacturing precision
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 approach enables spectacle lenses with a consistent edge thickness, improving optical performance and aesthetic appeal, facilitating edging processes, and reducing overall lens thickness, particularly beneficial for frames with asymmetrical designs.
Implementation Method 1
a spectacle lens (10) having a prescribed power and an edge contour (12) fitted to a predefined spectacle frame, wherein the spectacle lens (10) has a locally varying refractive index
Data Source
AI summary
A computer-implemented method generates design data for manufacturing a single vision spectacle lens having a prescribed power and an edge contour fitted to a predefined spectacle frame. Prescription information regarding the prescribed power for the spectacle lens and geometrical information regarding the predefined spectacle frame is provided. Moreover, a geometrical profile of at least one surface of the spectacle lens is optimized. Further, a spatial variation of a refractive index of the spectacle lens is optimized, wherein optimizing the geometrical profile of the surface of the spectacle lens and optimizing the spatial variation of the refractive index of the spectacle lens are carried out such that an optical power of the spectacle lens corresponds to the prescribed power and an edge thickness of an edge contour of the spectacle lens fitted to the geometrical information regarding the predefined spectacle frame varies by 0.5 mm or less over the edge contour.