Toric Contact Lens Mold Detectable Features Axis Alignment
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Solution Overview
Problem
Current methods for manufacturing toric contact lenses require an additional step to measure the axis angle of the lens after it is removed from the mold, increasing cycle time and reducing efficiency in high-speed automated environments.
Innovation Solution
The method involves providing anterior and posterior mold sections with detectable features that allow for the measurement of the axis angle between them before assembling and curing, eliminating the need to measure the axis alignment on the lens itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If axis angle measurement is performed after lens removal from mold, then measurement accuracy is ensured, but cycle time increases and productivity decreases
Solution Approach 1:
The patent applies preliminary action by measuring the axis angle of the lens while it is still in the mold, before the lens is removed. This is achieved by providing detectable features on the mold sections and using a detection device to measure the axis angle during the molding process itself, eliminating the need for post-removal measurement and thereby reducing cycle time while maintaining measurement accuracy
2Measurement precision
If additional inspection step is added for axis alignment measurement, then measurement precision is improved, but device complexity and process steps increase
Solution Approach 1:
The patent merges the axis alignment measurement function with the existing mold structure by integrating detectable features directly onto the mold sections. The detection device is positioned to measure these features during the normal molding process, combining the measurement function with the manufacturing process rather than adding a separate, complex inspection system
Solution Approach 2:
The patent uses detectable features on the mold sections as intermediaries to enable axis angle measurement. These features serve as mediators between the measurement system and the lens, allowing indirect measurement of the axis angle through the mold features rather than requiring direct measurement of the lens itself, thereby simplifying the measurement process
Data Source
AI summary
A method of measuring an axis angle of a toric contact lens including a posterior toric central zone having a cylindrical axis, and an anterior lens surface forming a ballast that has an axis of orientation offset from the cylindrical axis at a selected rotational angle is disclosed. The method involves (a) providing anterior and posterior mold sections including respective anterior and posterior mold cavity defining surfaces, wherein the posterior mold cavity defining surface includes a toric central zone and the anterior mold cavity defining surface is shaped to provide the ballast, the mold sections being alignable at multiple rotational positions; (b) providing a detectable feature on each of the anterior and posterior mold sections at a predetermined angular location with respect to the tonic and ballast axes thereof, respectively; (c) rotating the detectable feature of the posterior mold section relative to the detectable feature of the anterior mold section, wherein the detectable feature of the anterior mold section is a zero reference; and (d) measuring the axis angle between the detectable feature of the posterior mold section relative to the detectable feature of the anterior mold section after rotational displacement of the mold sections during toric contact lens formation.