Laminated Optical Element Adhesive for Wheel Edging Resistance

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Solution Overview

Problem

The adhesion between functional films and optical base elements in laminated optical elements, such as ophthalmic lenses, is prone to delamination during manufacturing processes like wheel edging, especially when exposed to mechanical stresses and water, leading to integrity issues.

Innovation Solution

A pressure-sensitive adhesive with a storage modulus between 1.0 and 1.6 × 10^5 Pa at 85°C, demonstrating dry and wet peel strengths of 20-40 N/25 mm, is used to maintain strong adhesion between the functional film and the optical base element, preventing delamination during edging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional adhesive systems are used for laminating functional films onto optical base elements, then the lamination process is simple and optical quality is maintained, but delamination occurs during wheel edging and other manufacturing processes

Engineering Contradiction:
Improveadhesion strengthVSAvoidadhesive system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by specifying precise rheological properties for the pressure-sensitive adhesive: storage modulus G' between 1.0 and 1.6×10^5 Pa at 85°C, and loss modulus G'' between 3.0 and 5.0×10^5 Pa at 85°C. These parameter specifications resolve the contradiction by defining an adhesive system that achieves reliable adhesion (preventing delamination during edging) while maintaining optical quality and avoiding excessive complexity through quantifiable performance criteria.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the adhesive provides strong adhesion to prevent delamination, then reliability improves, but the adhesive may interfere with optical quality or manufacturing processability

Engineering Contradiction:
Improvewheel edging resistanceVSAvoidoptical quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by changing the rheological parameters of the adhesive to achieve a specific balance: the storage modulus G' (1.0-1.6×10^5 Pa) ensures sufficient adhesion strength for wheel edging resistance, while the loss modulus G'' (3.0-5.0×10^5 Pa) provides appropriate damping and optical compatibility. This parameter optimization allows the adhesive to maintain both reliability during manufacturing and optical quality for the final product.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material principles by formulating the pressure-sensitive adhesive as a sophisticated composition that combines multiple functional components. This composite adhesive system integrates adhesion promoters, optical clarity agents, and rheology modifiers to simultaneously achieve strong adhesion (wheel edging resistance) and maintain optical quality, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #40Composite materials

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 solution ensures that the functional laminated optical elements exhibit improved wheel edging resistance and maintain integrity throughout the manufacturing process, including severe surfacing, polishing, and wet edge cutting, without separation between layers.

Implementation Method 1

said pressure-sensitive adhesive layer has a storage modulus G' between 1.0 and below 1.6 10^5 Pa at 85°C

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3436210B1Functionalized laminated optical element with improved edging resistance
Publication Date: 2024.06.12 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

The invention relates to a functionalized laminated optical element comprising: - An optical base element; - A functional film structure consisting of a single layer or a multilayer structure; - A layer of a pressure-sensitive adhesive of optical quality, placed between one surface of the optical base element and the functional film structure so as to permanently retain said functional film structure on the surface of the optical base element. Said functionalized laminated optical element maintains its integrity after typical processing of an optical article which includes wheel edging. More particularly the invention relates to the use of a specific adhesive system for improving the wheel edging resistance of functionalized laminated optical element. The functional laminated optical may be an ophthalmic lens.