Adaptation Layer for Antireflective Lenses

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Solution Overview

Problem

Existing antireflective coatings for ophthalmic lenses are designed for specific refractive indices, making it challenging to achieve similar color characteristics across lenses with varying refractive indexes, which limits their cosmetic appeal and practicality.

Innovation Solution

Incorporating a three-quarter wave thickness adaptation layer with an intermediate refractive index between the substrate and the antireflective stack, broadening the coating's performance across a range of substrates with different refractive indices, ensuring consistent color characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single antireflective coating design is used, then manufacturing complexity is reduced, but color characteristics become inconsistent across lenses with different refractive indexes

Engineering Contradiction:
Improveantireflective coating designVSAvoidcolor characteristics
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent introduces an adaptation layer as an intermediary component between the substrate and the antireflective stack. This adaptation layer has a refractive index intermediate between that of the substrate and the antireflective coating, serving as a transition medium that enables a single antireflective design to work effectively across substrates with varying refractive indexes while maintaining consistent color characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the refractive index parameter of the adaptation layer to be intermediate between the substrate and the antireflective coating. By adjusting this parameter, the system achieves broad compatibility across different substrate types without requiring multiple specialized coating designs, thus resolving the contradiction between design simplicity and color consistency.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If antireflective coatings are optimized for specific refractive indexes, then color characteristics are consistent, but manufacturing complexity increases due to multiple design requirements

Engineering Contradiction:
Improvecolor characteristicsVSAvoidantireflective coating design
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The adaptation layer serves multiple functions: it provides optical matching for substrates with different refractive indexes, enables a universal antireflective coating design to work across various substrate types, and maintains consistent color characteristics. This multi-functionality eliminates the need for multiple specialized coating designs.

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

Solution Approach 2:

The adaptation layer acts as a universal intermediary that mediates between substrates of various refractive indexes and a single antireflective coating design, enabling one coating design to serve multiple substrate types while maintaining color consistency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If quarter wavelength and half wavelength layers are used, then broad band antireflection is achieved, but color characteristics vary noticeably with substrate refractive index changes

Engineering Contradiction:
Improvelight transmissionVSAvoidcolor characteristics
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The adaptation layer serves as an optical intermediary that stabilizes the interface between substrates of varying refractive indexes and the quarter/half wavelength antireflective layers. This mediation reduces the sensitivity of color characteristics to substrate refractive index variations while preserving the broad band antireflection performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By changing the refractive index parameter of the adaptation layer to an intermediate value, the system reduces the contrast mismatch at the substrate-coating interface. This parameter adjustment stabilizes the optical interference conditions, making color characteristics less sensitive to substrate variations while maintaining effective antireflection.

Inventive Principle:
Principle #35Parameter changes

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 achieves a mean reflection factor of less than 2% over the visible spectrum, providing consistent and aesthetically pleasing color characteristics across lenses with varying refractive indices, enhancing their cosmetic and functional performance.

Implementation Method 1

a three-quarter wave thickness and an intermediate refractive index between nmin and nmax. For the design wavelength, a three-quarter wave layer will have the same effect as a single quarter wave layer. However, for wavelength away from design wavelength, a three-quarter wave layer brings better interference conditions to reduce light reflection and fringes over the whole visible spectrum.

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3037851B1Adaptation layer for antireflective designs on lenses of various refractive indexes
Publication Date: 2019.07.03 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

The present invention relates to an antireflective stack designed to provide similar reflected light characteristics on lenses of various refractive indexes. This antireflective stack may be coated on an ophthalmic lens, especially a spectacle lens.