Toric Contact Lens Mold Alignment Control

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Solution Overview

Problem

Conventional toric contact lens manufacturing processes face challenges in maintaining precise alignment of mold halves, leading to tilting and rotation issues, which result in out-of-specification lenses and misalignment of sphere and cylinder powers, due to the unsecured nature of one mold half and its use across multiple stock-keeping units.

Innovation Solution

The method and apparatus ensure controlled alignment of both mold halves using triangular-shaped projecting tabs and a pallet system that prevents tilting and rotation, allowing for individual optimization of front and back mold halves for improved toric axis control and lens optics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If one mold half is angularly rotated to obtain desired toric axis orientation, then lens alignment on-eye is improved, but mold half stability deteriorates as it becomes free to shift from desired position

Engineering Contradiction:
Improvetoric axis orientationVSAvoidmold half position stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The system segments the mold alignment control by providing separate adjustment mechanisms for each mold half (front and back), allowing independent positioning of each mold half relative to the optical axis without affecting the other, thereby maintaining stability while achieving precise toric axis orientation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the control parameter from rotating one entire mold half to independently adjusting the tilt and rotation parameters of each mold half separately, enabling precise control of toric axis orientation while maintaining mold half stability through controlled parameter adjustments

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If one mold half is used to produce multiple SKUs, then device versatility is improved, but manufacturing precision deteriorates as the mold half cannot be optimized for any one SKU

Engineering Contradiction:
ImproveSKU production rangeVSAvoidtoric axis control precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system implements dynamic adjustability where each mold half can be independently tilted and rotated to different positions, allowing the mold assembly to be optimized for each specific SKU while maintaining the capability to produce multiple different SKUs by adjusting the parameters

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mold assembly achieves multi-functionality by allowing each mold half to be independently positioned, enabling the same mold assembly to be optimized for producing multiple different SKU types with precise toric axis control for each specific lens design

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If mold halves are not precisely aligned, then ease of operation is improved as adjustment is simpler, but manufacturing precision deteriorates due to tilting and rotation issues

Engineering Contradiction:
Improvemold adjustment simplicityVSAvoidmold half alignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention replaces complex mechanical rotation of one mold half with a simplified system of independent tilt and rotation adjustments for each mold half, making the alignment process easier to operate while achieving superior precision through controlled mechanical adjustments of each component separately

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP1981691B1Axis control in toric contact lens production
Publication Date: 2010.12.08 JOHNSON & JOHNSON VISION CARE INC
  • EP1981691B1 patent drawingFigure 1a~1b
  • EP1981691B1 patent drawingFigure 2
  • EP1981691B1 patent drawingFigure 3

AI summary

The invention provides methods of manufacturing toric lenses, apparatuses useful in the method of the invention, and lenses produced according to the method in which method the position of one mold half in relation to its complementary mold half is more precisely controlled so that tilting and rotation of the mold halves in relation to each other is substantially eliminated.