Ophthalmic Lens Crib Diameter Standardization
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Solution Overview
Problem
The manufacturing process of ophthalmic lenses faces challenges in achieving a consistent crib diameter for lens blanks, leading to varied dimensions and requiring adjustments in equipment, particularly for coating processes, due to the constraints of existing methods.
Innovation Solution
A method is implemented using a processing module to define a temporary crib diameter that satisfies specific constraints, including being large enough for processing and including reference points for the optical center, with the crib diameter chosen from predetermined discrete values, ensuring adaptability and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing method of defining crib diameter based on blocking location is used, then the lens blank can be processed through various production steps, but the crib diameter varies extensively requiring adjustments in equipment and manufacturing parameters
Solution Approach 1:
The patent changes the parameter definition from blocking location-based to lens shape-based. The crib diameter is now defined as a function of the lens shape parameters (maximum radius, minimum radius, optical center position) rather than the blocking location, which directly causes the variability problem. This parameter change ensures consistent crib diameters while maintaining equipment adaptability.
Solution Approach 2:
The patent performs preliminary calculation of the crib diameter based on the lens shape parameters before the actual surfacing operation. By pre-defining the crib diameter constraints and checking against equipment capabilities in advance, the method avoids variability and equipment adjustment issues during production.
2Ease of manufacture
If the crib diameter is defined based on blocking location, then the lens blank can be handled during production steps, but the population of potential crib diameters becomes extremely varied
Solution Approach 1:
The patent fundamentally changes the parameter basis from blocking location to lens shape characteristics. The new definition uses the maximum radius, minimum radius, and optical center position to calculate crib diameter, which naturally constrains the variability while preserving the handling functionality during production steps.
3Adaptability or versatility
If equipment is adjusted to accommodate varied crib diameters, then different lens shapes can be manufactured, but the manufacturing process complexity increases
Solution Approach 1:
The patent performs preliminary verification of equipment capability against the calculated crib diameter constraints before manufacturing. This advance checking eliminates the need for complex real-time adjustments during production, reducing process complexity while maintaining the ability to manufacture different lens shapes.
Solution Approach 2:
By changing the crib diameter definition to be based on lens shape parameters, the patent creates a systematic approach that works across different lens types without requiring equipment reconfiguration, thereby reducing manufacturing process complexity.
Data Source
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AI summary
A method of preparing a lens blank for a further operation of surfacing to transform the lens blank into a surfaced lens for further transformation into a lens having a lens shape, the operation of surfacing including processing the lens blank so that the surfaced lens exhibits a crib diameter, the method being implemented using a processing module and comprising: - based on input data (ID) which define the lens shape, defining a temporary crib diameter (Dtemp) so that said temporary crib diameter satisfies a set of constraints which includes at least: - a first constraint whereby the temporary crib diameter (Dtemp) is large enough for the surfaced lens having said temporary crib diameter to be suitable to be processed into said lens, - a second constraint whereby the temporary crib diameter is large enough for the surfaced lens having said temporary crib diameter to include a plurality of reference points defined on the lens blank and which together identify an optical center of the lens, - choosing the crib diameter as a function of the temporary crib diameter (Dtemp), said choosing the crib diameter being configured so that, when a step cribbing configuration is destined to be applied to the operation of surfacing, said crib diameter is chosen among at least one predetermined discrete value (Val1).