Spectacle Lens Quality Control via Surface Topography Mapping
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Solution Overview
Problem
Existing methods for quality control of spectacle lenses are inadequate in detecting manufacturing defects reliably, as they primarily focus on reference points and do not account for deviations at other points on the lens, which can lead to undetected defects.
Innovation Solution
A method that determines the topography of spectacle lenses, calculates local optical sizes, and evaluates quality measures by comparing actual values with target values, using a coordinate system to assess optical effects across the lens surface, including dioptric sizes, beam deflection, and overall magnification, while avoiding the need for additional measurements that could damage the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quality control is performed only at reference points according to standards, then measurement process is simple and fast, but manufacturing defects at other points cannot be reliably detected
Solution Approach 1:
The patent divides the lens surface into multiple measurement points beyond just the reference points. By segmenting the quality control process into multiple discrete measurement locations across the lens surface, the system achieves more comprehensive defect detection while maintaining a structured and manageable measurement approach.
Solution Approach 2:
The patent transitions from point-based reference measurements to a two-dimensional surface mapping approach. By evaluating optical quantities across the entire lens surface in the X-Y coordinate system, the method adds spatial dimensionality to quality control, enabling detection of defects at any location rather than only at predetermined reference points.
2Reliability
If additional measurements are performed to detect defects, then defect detection capability improves, but risk of lens damage increases
Solution Approach 1:
The patent replaces physical contact-based measurement methods with optical measurement techniques. By using light to measure optical quantities such as surface topology, spherical effect, and astigmatic effect, the system achieves comprehensive defect detection without mechanical contact that could damage the lens.
Solution Approach 2:
The patent creates an optical model or digital representation of the lens surface and its optical properties. By measuring and recording optical quantities to build a comprehensive model of the lens, the system achieves thorough defect detection while avoiding repeated physical handling and potential damage from multiple measurement attempts.
3Manufacturing precision
If comprehensive surface evaluation is performed across the entire lens, then quality assessment completeness improves, but measurement time and complexity increase
Solution Approach 1:
The patent employs a measurement system capable of simultaneously determining multiple optical quantities (surface topology, spherical effect, astigmatic effect, beam deflection) at multiple points across the lens surface. This multi-functional approach achieves comprehensive quality assessment in a single integrated measurement process rather than requiring separate measurements for each parameter.
Solution Approach 2:
The patent implements continuous surface scanning or mapping to evaluate optical quantities across the entire lens surface without interruption. By maintaining continuous measurement action across the lens area, the system achieves complete quality assessment efficiently, avoiding repeated positioning and measurement cycles that would increase total measurement time.
Data Source
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AI summary
The invention relates to a method for the quality control of a spectacle lens (12). The method comprises the following steps: determining the topography of at least one optically effective surface (20) of the spectacle lens (12); calculating local actual values I[X,Y] of at least one optical quantity of the spectacle lens (12) taking into account the determined topography; calculating local deviations F[X,Y] of the calculated local actual values I[X,Y] from local target values S[X,Y] for the at least one optical quantity; determining a quality measure Q for the spectacle lens (12) by evaluating the calculated local deviations F[X,Y]; and evaluating the determined quality measure Q according to a quality specification.