Ophthalmic Lens Base-Curve Selection Method
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Solution Overview
Problem
Current methods for selecting base-curves for ophthalmic lenses are limited, failing to adequately address the increasing need for customization based on optical and aesthetic preferences without compromising optical quality.
Innovation Solution
A method that calculates a target lens according to prescription data, selects base-curves based on threshold differences in optical and geometrical parameters, and chooses a customized base-curve to meet specific criteria, such as optical performance and thickness, to enhance the choice panel without degrading optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a limited number of semi-finished lens blanks with standard base-curves are used, then manufacturing costs and inventory requirements are minimized, but the ability to customize lenses according to optical and aesthetic preferences is limited
Solution Approach 1:
The patent applies parameter changes by systematically varying the base-curve values across a broader range (from +0.75D to +12.00D with 0.25D increments) and introducing multiple refraction index options (1.50, 1.53, 1.56, 1.59, 1.61, 1.67, 1.70, 1.74). This allows the lens blank system to adapt to diverse prescription requirements and aesthetic preferences while maintaining a structured, manageable series organization.
Solution Approach 2:
The patent segments the base-curve series into multiple refraction index families (1.50, 1.53, 1.56, 1.59, 1.61, 1.67, 1.70, 1.74), with each family containing its own progression of base-curves. This segmentation allows manufacturers to organize inventory by refraction index while providing comprehensive customization options within and across families, resolving the contradiction between variety and complexity.
2Adaptability or versatility
If more base-curves are available in the base-curve series, then the choice panel for customization is enhanced, but the number of moulds and stocking costs increase
Solution Approach 1:
The patent creates a universal base-curve series that serves multiple refraction indices (1.50, 1.53, 1.56, 1.59, 1.61, 1.67, 1.70, 1.74) with a consistent progression pattern. Each refraction index family can function independently or be combined with others, allowing manufacturers to produce a comprehensive selection range while using a standardized mould design that reduces the total number of unique moulds required.
Solution Approach 2:
By establishing a systematic parameter progression (0.25D increments from +0.75D to +12.00D) that applies across all refraction indices, the patent enables manufacturers to expand the selection range efficiently. The regular pattern allows for predictable inventory planning and reduces the need for excessive mould variations, as the same mould structure can be adapted across different refraction index families.
3Reliability
If a comprehensive base-curve series is used to meet all prescription requirements, then optical quality can be maintained across diverse prescriptions, but manufacturing complexity and inventory management become more difficult
Solution Approach 1:
The patent maintains optical quality consistency by applying a uniform parameter progression (0.25D steps) and standardized refraction index values across the entire base-curve series. This systematic approach ensures that each base-curve within a refraction index family follows the same optical principles, guaranteeing consistent optical performance while simplifying inventory management through predictable, organized categorization.
Solution Approach 2:
The patent applies local quality by allowing each refraction index family to have its own optimized base-curve progression while maintaining overall series consistency. This enables tailored optical optimization for specific refraction indices (addressing local optical requirements) while the unified series structure simplifies global inventory management and manufacturing processes.
Data Source
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AI summary
A method for selecting base-curves for an ophthalmic lens according to given prescription data comprising the steps of: - providing a base-curve series consisting of a plurality of base-curves; - calculating a target lens according to the prescription data; - calculating the base-curves calculated lenses according to the prescription data; - selecting, for at least an optical parameter and/or a geometrical parameter, a threshold value for the difference between the base-curves calculated lenses values and the target lens value of said parameter(s); - determining the list of the base-curves of the base-curve series where said difference for said parameter(s) is less or equal to the selected threshold value(s).