Ophthalmic Lens Mold Closure Force Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for manufacturing ophthalmic lenses, particularly contact lenses, face challenges in achieving rapid mold closure without introducing imperfections such as bubbles or incomplete lens formation due to improper velocity control during the mold closure process.

Innovation Solution

A method and apparatus that measure and control the force applied during mold closure, ensuring the mold halves are acceptably closed by maintaining a predetermined threshold force, and adjust velocities to prevent splashing or inadequate polymer distribution, using a force sensor and controller to manage the movement of mold halves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mold halves are brought together at a rapid velocity, then productivity is improved, but manufacturing precision deteriorates due to splashing, bubbles, and incomplete lens formation

Engineering Contradiction:

Improvemold closure speedVSAvoidlens formation quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the mold closure velocity variable rather than constant. The system transitions from a static, fixed-speed closure approach to a dynamic, multi-stage velocity profile that adapts to the specific requirements of different closure phases (approach, contact, full closure), thereby resolving the contradiction between speed and precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the velocity parameter during the mold closure process. By implementing different velocity values for different stages (higher velocity for approach, lower velocity for contact and full closure), the system optimizes both productivity and manufacturing precision without compromise.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If mold halves are brought together at a slow velocity, then manufacturing precision is improved, but productivity deteriorates due to extended closure time

Engineering Contradiction:

Improvelens formation qualityVSAvoidmold closure speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system resolves the contradiction by implementing a dynamic velocity profile that is slow during critical contact phases to ensure precision, then accelerates during approach and full closure phases to maximize productivity. This dynamic adjustment eliminates the need to choose between speed and precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent maintains continuous useful action by keeping the mold closure process ongoing without idle waiting. The multi-stage velocity profile ensures that the mold halves are continuously moving through all necessary phases (approach, contact, full closure) without interruption, maximizing productivity while maintaining precision through controlled velocity at each stage.

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If a force measurement system is added to verify mold closure, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improveclosure verification accuracyVSAvoidapparatus structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The force measurement system is integrated into the existing mold closure mechanism, allowing the system to self-verify its own closure quality. The force sensor detects when the mold halves are properly closed without requiring external verification equipment, thereby improving precision while minimizing added complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical verification mechanisms with a force measurement system. Instead of using complex mechanical linkages or multiple sensors to verify closure, a single force sensor measures the force required to close the mold, providing accurate verification with minimal added complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces variability in lens diameters and defective lenses by ensuring consistent mold closure, improving the quality of contact lenses by maintaining a constant force and velocity during the contacting stage.

Implementation Method 1

measuring the force applied during the contacting step; and determining that the mold halves have formed a closed mold assembly, e.g., are acceptably closed, when the force is greater than or equal to a predetermined threshold force

Methodology Applied

Scientific EffectForce measurement: Force

Data Source

PatentUS9937640B2Apparatus and method for closure of ophthalmic lens molds

Publication Date: 2018.04.10 COOPERVISION INT LTD

AI summary

Apparatus and methods for manufacturing ophthalmic lenses by bringing together a pair of mold halves to form a closed mold assembly, are described. The method includes measuring a force applied to bring the mold halves together. The apparatus includes at least one force sensor in operative communication with a single pair of mold halves, and a controller for controlling a velocity of movement of a mold half and for determining when a measured force or average measured force is greater than or equal to a predetermined threshold force.