Eyewear Optical Film with Cholesteric Liquid Crystal Reflection

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Solution Overview

Problem

Conventional polarization sunglasses face challenges in achieving high antiglare properties and metallic color reflection without using linear polarization elements, and they are often costly due to the use of cholesteric liquid crystals and high-performance polarization elements.

Innovation Solution

An optical film comprising at least one light reflection layer and a light control layer, where the light reflection layer includes a cholesteric liquid crystal layer that reflects circularly polarized light, and the light control layer is a quarter wave plate, laminated in a specific order to achieve the desired antiglare effect and metallic color tone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a multi-layered film is provided on the lens surface by evaporation to achieve metallic color reflection and improved visibility, then the visibility for the wearer is improved, but the film is difficult to clean, lacks adhesion in humid environments, and is difficult to manufacture uniformly on curved surfaces

Engineering Contradiction:
ImprovevisibilityVSAvoidmanufacturing difficulty
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent replaces the evaporation coating process (physical vapor deposition) with a lamination process using pre-formed films. Instead of evaporating materials onto the lens surface, the invention uses adhesive layers to bond functional films (polarization element, multi-layered film for metallic reflection) to the lens, eliminating the complexity of uniform evaporation coating on curved surfaces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent divides the optical system into separate functional layers: the lens substrate, an adhesive layer, a polarization element, and a multi-layered film for metallic color reflection. Each layer is manufactured independently and then bonded together, allowing each component to be optimized separately and assembled without requiring complex in-situ coating processes.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a multi-layered film is provided between the polarization element and support body to avoid cleaning issues, then handling is improved, but the reflection performance is reduced due to refractive index differences and bonding difficulties with inorganic materials

Engineering Contradiction:
ImprovehandlingVSAvoidreflection performance
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent introduces an adhesive layer as an intermediary between the polarization element and the multi-layered film, and another adhesive layer between the multi-layered film and the support body. These adhesive layers serve as mediators that enable bonding between incompatible materials (organic polarization element and inorganic multi-layered film) while maintaining optical performance by being positioned away from the critical reflection interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent moves the multi-layered film from the lens surface (external dimension) to the internal structure between the polarization element and support body. This dimensional repositioning eliminates the need for surface cleaning while maintaining reflection performance by using adhesive layers to preserve the optical interface quality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If cholesteric liquid crystal and high-performance polarization elements are used to achieve high antiglare properties and metallic color reflection, then the antiglare effect is improved, but the cost increases significantly

Engineering Contradiction:
Improveantiglare propertyVSAvoidcost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the parameters of the multi-layered film (layer thicknesses, refractive indices, material compositions) to achieve metallic color reflection and antiglare effects without requiring expensive cholesteric liquid crystals. By carefully controlling the optical parameters of conventional materials, the invention achieves similar performance at lower cost.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive, complex cholesteric liquid crystal structures with simpler, cheaper inorganic multi-layered films that can be manufactured using conventional techniques. The invention uses cost-effective materials such as metal oxides and adhesives instead of expensive liquid crystal compositions, making high-performance eyewear more affordable.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

This configuration allows for the production of eyewear with high antiglare properties and metallic color reflection at a lower cost, without the need for linear polarization elements, and is applicable to various eyewear types including protection glasses post-cataract operation.

Implementation Method 1

the light reflection layer includes a cholesteric liquid crystal layer that reflects circularly polarized light in a visible light range

Methodology Applied
Scientific EffectCholesteric liquid crystal reflection: Cholesteric Liquid Crystal

Implementation Method 2

the light control layer is a quarter wave plate

Methodology Applied
Scientific EffectQuarter wave plate: Birefringence

Implementation Method 3

the multi-layered film achieves reflection performance based on a refractive index difference between layers

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3441802B1Optical film for eyewear, and optical laminate and eyewear using the optical film
Publication Date: 2024.01.17 NIPPON KAYAKU CO LTD
  • EP3441802B1 patent drawingFigure 1
  • EP3441802B1 patent drawingFigure 2
  • EP3441802B1 patent drawingFigure 3

AI summary

An optical film for eyewear includes a light control layer and at least one light reflection layer laminated in this order from an outer side with respect to a viewer, wherein the light reflection layer includes a cholesteric liquid crystal layer that reflects left-handed circularly polarized light or right-handed circularly polarized light in a visible light range, and the light control layer is a quarter wave plate.