Optical Lens Concave Marks for Molding Shape Correction
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Solution Overview
Problem
Existing methods for producing optical lenses with aspheric surfaces face challenges in accurately replicating the designed shape due to material shrinkage and stress during molding, leading to shape errors and complex correction processes that affect lens performance.
Innovation Solution
The use of a lens mold with convex transcriptional sections that form concave marks on the optical lens surface, allowing for precise detection and correction of shape errors by measuring the marks, ensuring accurate reproduction of the designed lens shape without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a marking is provided outside the lens effective portion for shape measurement, then the lens mold shape can be corrected based on measured values, but the amount of displacement in the effective optical surface cannot be directly calculated, making it impossible to accurately detect shrinkage state
Solution Approach 1:
The patent introduces a transcriptional mark as an intermediary element that bridges the lens mold and the molded lens. This mark is transcribed from the mold surface to the lens surface, allowing indirect measurement of mold shape through the lens while maintaining the ability to calculate displacement in the effective optical surface. The mark serves as a mediator that enables accurate shape detection without requiring direct measurement of the mold itself.
2Manufacturing precision
If a lens mold is produced again based on correction information from test molding, then shape errors can be corrected, but various processing conditions such as abrasion state, tool type, and chucking accuracy may change, preventing expected accuracy in surface shape reproducibility
Solution Approach 1:
The patent implements a feedback mechanism where the actual shape of the lens is measured using the transcriptional mark, and correction information is fed back to adjust the lens mold. This closed-loop feedback system continuously monitors and corrects shape deviations, ensuring that even when processing conditions change between mold productions, the final lens shape accuracy is maintained through iterative correction based on actual measurement data.
3Manufacturing precision
If multiple molds are produced to ensure shape accuracy, then lens performance can be maintained, but the molding process becomes complicated and productivity decreases
Solution Approach 1:
The patent enables the lens mold to self-correct its shape through the feedback mechanism. By measuring the actual lens shape using the transcriptional mark and calculating displacement in the effective optical surface, the system automatically generates correction information that is applied back to the mold. This self-service capability eliminates the need for multiple mold productions or complex external intervention, maintaining high shape accuracy while simplifying the molding process and improving productivity.
Data Source
AI summary
An optical lens 11, which has a lens section with a refractive power, has concave marks 33, 35, 37, and 39 which are formed to be recessed on a surface of the lens section, in an effective optical lens surface which contributes to image forming of the lens section. A width of each of these concave marks 33, 35, 37, and 39 is equal to or greater than 0.05 μm and equal to or less than 14 μm, and a depth of recession of each concave mark is equal to or greater than 0.05 μm and equal to or less than 5 μm.