Electrochromic Lens Wafer Shoulder for Infiltration-Resistant Bonding

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Solution Overview

Problem

Existing ophthalmic lenses, particularly electrochromic lenses, face challenges in assembly complexity and risk of water or dust infiltration between the wafer and optical element, with visible metal strips or glue beads compromising aesthetics.

Innovation Solution

A wafer with a perimeter shoulder and adhesive material applied only on the perimeter front surface, combined with an opaque coating to conceal metal strips, ensures secure bonding and prevents infiltration while maintaining optical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive material is applied between the wafer and optical element, then bonding strength is improved, but risk of water or dust infiltration increases

Engineering Contradiction:
Improvebonding strengthVSAvoidwater or dust infiltration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The wafer is divided into a central section and a perimeter section with different thicknesses. The perimeter section has a reduced thickness that matches the adhesive material thickness, creating a segmented structure that prevents infiltration pathways while maintaining bonding strength in the central region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the wafer are given different properties: the central section maintains full thickness for optical performance, while the perimeter section has reduced thickness to accommodate the adhesive layer without creating infiltration channels. This local differentiation resolves the contradiction between bonding and infiltration prevention.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If metal strips or glue beads are visible on the lens, then assembly simplicity is maintained, but aesthetic appeal deteriorates

Engineering Contradiction:
Improveassembly simplicityVSAvoidaesthetic appeal
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The visible metal strips and glue beads are extracted from the front-facing surface. The perimeter section is designed with reduced thickness to conceal the adhesive material, and metal strips are positioned on the back surface or edges where they are not visible, eliminating the aesthetic defect while maintaining assembly simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The perimeter section creates a visual transition that conceals the adhesive material and metal strips from view. By reducing the thickness at the perimeter, the structure naturally hides the non-aesthetic elements, creating a uniform appearance on the front surface while maintaining the functional assembly.

Inventive Principle:
Principle #32Color changes

3Object-affected harmful factors

If wafer thickness is reduced at the perimeter, then infiltration risk is decreased, but structural strength may deteriorate

Engineering Contradiction:
Improveinfiltration riskVSAvoidstructural strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The wafer structure is segmented into a thick central section that maintains structural integrity and optical properties, and a thin perimeter section that prevents infiltration. This segmentation allows each region to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wafer structure functions as a composite system where the central section provides structural strength and the perimeter section provides infiltration prevention. The combination of these two regions with different thicknesses creates a structure that simultaneously achieves both structural integrity and infiltration resistance.

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 enhances the durability and aesthetic appeal of electrochromic lenses by preventing dust and water ingress, while allowing for electronic control of light transmission.

Implementation Method 1

The wafer and optical element are bonded to each other by an adhesive material

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

An electrochromic cell typically has a structure comprising two flat transparent outer layers, for example two surfaces made of organic or mineral material, on which transparent electrically conductive coatings are deposited on the inner faces thereof. An electrochromic composition fills a cavity formed between the two electrically conductive coatings. It is thus possible to vary the light transmission value of the cell by applying an electric field between the electrically conductive coatings.

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Data Source

PatentEP4162315B1Electrochromic lens comprising a wafer having a perimeter shoulder
Publication Date: 2025.08.06 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP4162315B1 patent drawingFigure 1
  • EP4162315B1 patent drawingFigure 2A~2C
  • EP4162315B1 patent drawingFigure 2D

AI summary

The present invention concerns an optical system (1) comprising a wafer (3) and an optical element (5). The wafer and the optical element are bonded to each other by an adhesive material (7), and the wafer has a perimeter shoulder (9). Typically, the wafer comprises a back surface designed according to the prescription of a wearer and a front surface intended to be bonded to the optical element. The optical element can be an electrochromic cell.