Asymmetric Spacer for Lamination Defect Elimination

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Solution Overview

Problem

The existing lamination processes for Progressive Addition Lenses (PAL) fail to achieve full pressure in the vicinity of surface depressions, leading to coating defects due to the delicate nature of carriers and limitations in processing parameters like lamination pressure, height, bladder size, and shape.

Innovation Solution

A spacer with predetermined dimensions and configuration is positioned between the HMC carrier and the pressurized laminating device to asymmetrically increase pressure, specifically designed to match the curvature differences between the lens and the carrier, ensuring uniform coating application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If lamination pressure is increased to eliminate coating defects in the near vision zone, then coating quality improves, but the delicate carrier may be damaged

Engineering Contradiction:
Improvecoating qualityVSAvoidcarrier integrity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent introduces spacers positioned specifically at the near vision zone (depression area) of the carrier to create localized pressure enhancement. This allows increased pressure only where coating defects occur without subjecting the entire delicate carrier to high pressure that would cause damage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The spacers act as intermediary elements between the lamination device and the carrier, mediating the pressure transmission. They concentrate and redirect pressure to specific areas needing coating improvement while protecting the carrier from excessive overall pressure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If standard symmetric lamination pressure is applied, then the carrier is protected from damage, but lamination defects occur in the near vision zone due to surface depression

Engineering Contradiction:
Improvecarrier protectionVSAvoidcoating uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric pressure distribution by positioning spacers specifically in the near vision zone rather than uniform pressure across the entire carrier. This asymmetric approach compensates for the surface depression geometry and creates the necessary pressure variation to eliminate coating defects in affected areas.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

By placing spacers only in the near vision zone where the surface depression causes coating defects, the patent applies enhanced pressure locally to where it is needed most, while maintaining standard pressure elsewhere to protect the carrier.

Inventive Principle:
Principle #3Local quality

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 spacer effectively eliminates lamination defects by ensuring consistent pressure distribution across the lens surface, preventing carrier damage and improving the transfer of the Hard Multi-Coat layer, particularly in the near vision zone of PAL lenses.

Implementation Method 1

The spacer asymmetrically increases the pressure applied to the carrier to eliminate lamination defects

Methodology Applied
Scientific EffectPressure distribution: Pressure Gradient

Implementation Method 2

In its final position, the combination of heat and pressure fixes the HMC layer to the lens

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

the combination of heat and pressure fixes the HMC layer to the lens

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 4

As pressure is applied to one side of the elastomeric membrane, it deforms and contacts the HMC carrier

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2879862B1Asymmetric bladder compression for elimination of lamination defects on multifocal lenses
Publication Date: 2024.01.17 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP2879862B1 patent drawingFigure 1~2B
  • EP2879862B1 patent drawingFigure 3A~3B
  • EP2879862B1 patent drawingFigure 4A~6B

AI summary

A method and apparatus for elimination of lamination defects on multifocal lenses. The lamination method uses a flexible bladder (14, 14a) designed to apply pressure evenly across the lens (22) surface. A spacer (100a, 100b) is positioned between a Hard Multi-Coat carrier (26) and the flexible bladder. The spacer is located in a region of the carrier which is designated to deliver a coating to a section of the lens which is farthest from the carrier. The spacer asymmetrically increases the pressure applied to the carrier to eliminate lamination defects.