Flexible Support Element for Uniform Thermal Bonding of Ophthalmic Lens Packages

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Solution Overview

Problem

Existing methods for thermally bonding cover films to ophthalmic lens packages often result in insufficient or non-uniform bonding due to uneven support of the base part, leading to discarded products and inconvenient peel-off forces, and increasing mechanical pressure can cause delamination or excessive peel-off force.

Innovation Solution

A package holder with a flexible support element, made of an elastic material like silicone, is used to evenly distribute pressure during thermal bonding, allowing for a predetermined bonding force and temperature range that ensures uniform bonding without delamination, enabling easier peel-off and accommodating varying base part geometries and materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical pressure is increased during bonding to overcome insufficient bonding, then bonding strength is improved, but delamination occurs during peel-off and peel-off force becomes excessively high

Engineering Contradiction:
Improvebonding uniformityVSAvoidpeel-off convenience
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention changes the physical state of the package holder from rigid to flexible, allowing it to adapt its shape to the base part. This flexibility enables uniform pressure distribution across the bonding area without requiring excessive mechanical pressure, thereby achieving both strong bonding and easy peel-off. The flexible package holder deforms to match the base part geometry, ensuring consistent contact and heat transfer during bonding while reducing peak pressures that would cause delamination.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If mechanical pressure is increased during bonding, then bonding strength is improved, but some batches of cover film cannot be used due to optimum bonding temperature constraints

Engineering Contradiction:
Improvebonding strengthVSAvoidcover film batch compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The flexible package holder enables effective bonding at reduced mechanical pressures, which allows for broader temperature process windows. This flexibility in pressure application means that cover film batches with different optimum bonding temperatures can be processed successfully, as the system can compensate with extended time or adjusted temperature profiles rather than relying on high pressure alone.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If rigid package holder is used, then device complexity is reduced, but insufficient or non-uniform bonding occurs due to uneven base part support

Engineering Contradiction:
Improvepackage holder structureVSAvoidbonding uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention employs a flexible package holder that can deform to match the geometry of the base part, ensuring uniform contact and pressure distribution across the bonding area. This flexibility compensates for variations in base part thickness and shape without requiring complex rigid structures with multiple adjustment mechanisms, thereby achieving uniform bonding with a relatively simple device design.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The method achieves uniform thermal bonding with reduced mechanical forces, improving peel-off performance, allowing thinner cover films, and expanding the range of suitable bonding temperatures, thus increasing yield and reducing equipment wear and energy consumption.

Implementation Method 1

The flexible support element has a flexibility which is higher than the flexibility of the base part

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

applying heat to the bonding area, thereby thermally bonding together the cover film and the base part along the bonding area

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3386716B1Method for thermally bonding together a cover film of an ophthalmic lens package and a base part of the ophthalmic lens package
Publication Date: 2022.06.15 ALCON INC
  • EP3386716B1 patent drawingFigure 1
  • EP3386716B1 patent drawingFigure 2
  • EP3386716B1 patent drawingFigure 3~7

AI summary

A method for thermally bonding together a cover film (3) of an ophthalmic lens package (1) and a base part (2) of the ophthalmic lens package (1), such as a contact lens package, in particular a soft contact lens package, comprising the steps of - providing a package holder (9) supporting a base part (2) and a cover film (3) arranged thereon, the base part (2) comprising a depression (4) containing an ophthalmic lens (5) immersed in a liquid (6); - mechanically pressing the cover film (3) and the base part (2) together along a bonding area (7) having a shape completely enclosing the depression (4) while applying heat to the bonding area (7), thereby thermally bonding together the cover film (3) and the base part (2) along the bonding area (7); wherein the step of providing the package holder (9) includes arranging a flexible support element (18) on an upper surface (10) of the package holder (9) to form a support area (19) corresponding in shape to and being arranged in alignment with the bonding area (7), with the flexible support element (18) having a flexibility higher than the flexibility of the base part (2).