Variable Thickness Chipper Plates for Lens Optical Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining the optical properties of polycarbonate materials used in ophthalmic lens manufacturing are inadequate, leading to variations in lens quality due to reliance on standard chipper plates that do not accurately represent the properties of semi-finished lenses, resulting in potential defects and unnecessary rejections of production lots.
Innovation Solution
The use of a mold with cavities of different thicknesses to produce resin stabilization and product color chipper plates, which are subjected to cycle times and temperatures comparable to those used in semi-finished lens production, providing an accurate indication of optical properties without the need for mathematical extrapolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard chipper plates with uniform thickness are used for quality testing, then the testing process is simple and fast, but the optical properties measured do not accurately represent the semi-finished lenses produced from the material
Solution Approach 1:
The mold is divided into multiple cavities with different thicknesses (e.g., 3mm, 5mm, 10mm) to produce chipper plates of varying thicknesses. This segmentation allows simultaneous testing of different optical properties that correspond to different lens thicknesses, resolving the contradiction by making the testing device complex in structure but simple in operation, while significantly improving measurement accuracy.
Solution Approach 2:
The invention adds the dimension of thickness variation to the chipper plate testing process. Instead of using uniform thickness plates, the mold produces plates with different thicknesses in different cavities, allowing comprehensive optical property assessment that accurately represents semi-finished lenses of various thicknesses, thereby improving measurement precision without excessive complexity.
2Measurement precision
If mathematical extrapolation is used to predict lens color from chipper plate measurements, then the process avoids additional testing, but the predictions are inaccurate due to differences in manufacturing conditions
Solution Approach 1:
The invention performs preliminary quality control testing by producing chipper plates with different thicknesses that simulate the actual lens manufacturing conditions. This preliminary action with realistic test samples eliminates the need for time-consuming mathematical extrapolation and subsequent lens production testing, as the chipper plates themselves provide accurate predictions of lens optical properties.
Solution Approach 2:
The chipper plates are created as accurate copies of the actual lens manufacturing process by using the same mold cavities, materials, and processing conditions. This copying approach produces test samples that truly represent the optical properties of semi-finished lenses, making mathematical extrapolation unnecessary and reducing quality control time.
3Reliability
If production lots are rejected based on inaccurate chipper plate testing, then defective material does not reach customers, but good material may be incorrectly rejected
Solution Approach 1:
The invention applies local quality testing by creating chipper plates with different thicknesses in different mold cavities, each optimized for specific optical property measurements. This localized testing approach ensures that each aspect of quality is assessed under conditions that accurately represent actual lens production, improving reliability of quality assurance while reducing false rejections of good material.
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3
AI summary
Optical qualities of a production lot of base material used in the fabrication of semi-finished lenses may be accurately determined by employing chipper plate samples produced from the base material in accordance with aspects of the present invention. In various implementations of the present invention, the chipper plates samples may be fabricated by subjecting base material to an extended cycle time and temperature profile using a mold having cavities of different thicknesses. The resulting chipper plates provide an improved indication of the color of semi-finished lenses molded from the production lot as well as an improved indication of resin stabilizer defects that may be utilized during a pelletizing process to control and enhance the quality of a production lot. Furthermore, the chipper plates may be provided by suppliers as samples of a production lot to enable customers to base purchasing decisions on a reliable and accurate measure of optical properties.