Mold Die Correction for Eyeglass Lens Optical Continuity
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Solution Overview
Problem
The existing manufacturing methods for mold dies used in thermally drooping molding for eyeglass lenses often introduce accidental errors into the design data, leading to improper shaping of the lenses, which can result in broken optical properties and the inability to maintain intended design specifications, especially for complex progressive power lenses.
Innovation Solution
A method that involves creating design data for mold dies based on prescription information, specifying error amounts at reference points, defining correction surfaces to correct these errors, and combining these surfaces with the original design data to create a corrected molding surface, ensuring that the design data accurately represents the intended shape without introducing accidental errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If design data is corrected by repeatedly altering design data itself based on measured error amounts at multiple evaluation points, then manufacturing precision of the mold die improves, but the optical property of the eyeglass lens deteriorates due to unintended aberration components and broken optical continuity
Solution Approach 1:
The patent divides the correction process into two independent stages: (1) correcting individual evaluation points independently to eliminate manufacturing errors, and (2) performing final optimization to ensure optical continuity. This segmentation prevents the mixing of accidental errors into design data while maintaining optical properties.
Solution Approach 2:
The patent applies preliminary correction to remove manufacturing errors from the molding surface shape before final optical optimization. By eliminating accidental errors in advance, the subsequent optical design process works with clean base data, preventing propagation of errors through the design iterations.
2Manufacturing precision
If design data is altered to correct errors at all evaluation points, then manufacturing precision improves, but device complexity increases due to the need for repeated trial-and-error redesign cycles
Solution Approach 1:
The patent segments the correction process into distinct stages: error removal from molding surface, then optical optimization. This eliminates the need for repeated full redesign cycles, reducing design process complexity while achieving the same precision goals.
Solution Approach 2:
By performing preliminary error correction on the molding surface before final optical design, the patent eliminates the need for multiple trial-and-error cycles. The design process starts with already-corrected base data, significantly reducing overall complexity.
3Manufacturing precision
If multiple glass materials and mold dies with different shapes are prepared to control molding distance, then manufacturing precision improves, but productivity deteriorates due to the need for repeated preliminary molding and shape correction
Solution Approach 1:
The patent replaces the mechanical trial-and-error approach of preparing multiple mold dies with a computational correction method. By using computer-based error correction algorithms on the molding surface shape, the system achieves precise distance control without needing multiple physical prototypes, significantly improving productivity.
Solution Approach 2:
The patent performs preliminary computational correction of the molding surface shape using measured error data before actual lens production. This eliminates the need for repeated preliminary molding cycles with different mold dies, streamlining the production process while maintaining precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that the mold dies are designed and manufactured to maintain intended optical properties, preventing the formation of eyeglass lenses with broken optical continuity and allowing for precise correction of errors at specific points, enhancing the precision and accuracy of the lens shaping process.
Implementation Method 1
glass material made of thermosoftening material such as glass is placed on a mold die and is softened to closely contact the mold die by being heated to a temperature higher than or equal to the softening point
Data Source
AI summary
A manufacturing method for a mold die comprising: making design data for a molding surface based on predetermined prescription information; creating the molding surface in accordance with the design data; specifying error amounts at first and second corresponding points defined on the created molding surface respectively corresponding first and second reference points; defining a first correction surface based on an error amount specified at the first corresponding point; of defining a second correction surface based on the first correction surface and an error amount specified at the second corresponding point, wherein the second correction surface has no power at the first corresponding point; combining a design surface by the design data, the first correction surface and the second correction surface, and corrects the design data based on combined data after the combining; and creating the molding surface in accordance with the corrected design data.