Optical Lens Processing with Offset Reference Points
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Solution Overview
Problem
The manufacturing of optical lenses from unfinished lens members is inefficient due to the need for larger semi-finished blanks to accommodate dissymmetric spectacle frames, leading to material wastage and costly management, especially with the increasing trend towards larger frames.
Innovation Solution
A method that virtually offsets the optical reference point with respect to the geometrical centre reference point of the unfinished lens member, allowing the contour of the optical lens to fit within the available diameter, reducing the need for multiple semi-finished blank sizes and optimizing processing by transforming surface datasets and using offsetting and prism configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a semi-finished lens blank of significantly larger diameter is used to accommodate dissymmetric spectacle frames, then the optical lens can be produced with the required size and shape, but material wastage increases
Solution Approach 1:
The patent applies asymmetry by allowing the optical reference point to be offset from the geometrical centre reference point of the semi-finished lens blank. This enables dissymmetric spectacle frames to be accommodated while using a smaller, more appropriately sized lens blank, thereby reducing material wastage. The offset distance is calculated based on the frame dimensions and optical requirements, optimizing the use of lens material.
2Shape
If a semi-finished lens blank of significantly larger diameter is used to accommodate dissymmetric spectacle frames, then the required lens size and shape can be achieved, but the cost of managing multiple blank sizes increases
Solution Approach 1:
The patent implements universality by enabling a single geometrical centre reference point on the semi-finished lens blank to serve multiple functions. By offsetting the optical reference point from this central point, the system can accommodate various dissymmetric frame designs using the same blank size, eliminating the need to maintain inventories of multiple blank diameters and simplifying stock management.
3Loss of substance
If the optical reference point is offset from the geometrical centre reference point, then standard-sized semi-finished blanks can be used for dissymmetric frames, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the offset distance between the optical reference point and the geometrical centre reference point in a database. During processing, this pre-determined offset value is retrieved and used to position the lens blank correctly on the processing device, eliminating the need for complex real-time calculations and simplifying the processing workflow.
4Ease of manufacture
If the optical reference point coincides with the geometrical centre reference point, then processing is simplified and centered, but larger diameter blanks are required for dissymmetric frames leading to material wastage
Solution Approach 1:
The patent introduces an intermediary computational step that calculates the optimal offset distance between the optical reference point and the geometrical centre reference point. This intermediary calculation acts as a mediator, allowing the processing to remain centered and simplified while accommodating dissymmetric frame requirements, thus avoiding material wastage without compromising manufacturing ease.
Data Source
AI summary
A method of processing an unfinished optical lens member having a finished surface with a center reference point, and first and second surfaces, includes providing contour data defining the contour of the first surface in a finished cut state, the maximum distance between two points of the contour defined by Cmax; determining, an optical reference point of the first surface with respect to the contour, the optical reference point corresponding to a user's line of sight in the finished cut state, the maximum distance between the optical reference point and the contour defined by Mmax, providing a first surface dataset defining the second surface with respect to the optical reference point; and providing an unfinished optical lens member having a minimum distance RSF between the center reference point and the boundary of the unfinished lens member such that 2 RSF≧Cmax and RSF<Mmax.