Laminated Glass Interlayer Film for Directional Color Difference

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Solution Overview

Problem

Conventional interlayer films for laminated glass primarily focus on coloration but fail to enhance aesthetic quality, limiting their ability to provide distinct designs on opposite surfaces of laminated glass.

Innovation Solution

An interlayer film for laminated glass with a reflection layer and resin layers configured to achieve a color difference ΔE*ab of 0.5 or more between reflected light from opposite directions, utilizing nano-multilayer films and specific resin layers with varying refractive indices and thicknesses to create distinct designs on each surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional interlayer film with pigment or dye is used for coloration, then the window glass can be colored, but the aesthetic quality is not sufficiently enhanced and distinct designs on opposite surfaces cannot be achieved

Engineering Contradiction:
Improvecoloration capabilityVSAvoidaesthetic quality and design distinctiveness
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The interlayer film is divided into multiple functional layers: a first resin layer with a colored layer containing pigment or dye, a reflection layer, and a second resin layer with a colored layer. This segmentation allows each layer to contribute differently to the overall optical properties, enabling distinct designs when viewed from opposite surfaces while maintaining manufacturability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates asymmetric optical properties by positioning colored layers in the first and second resin layers at different locations relative to the reflection layer. This asymmetric configuration ensures that light reflected from opposite surfaces undergoes different optical paths and interactions, producing visually distinct designs on each surface of the laminated glass

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If a reflection layer is added to achieve distinct reflected light designs, then aesthetic quality is enhanced, but the device complexity increases

Engineering Contradiction:
Improveaesthetic qualityVSAvoidinterlayer film structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by giving specific regions of the interlayer film specialized functions: the first and second resin layers contain colored layers with specific pigments or dyes, while the reflection layer contains specific reflective particles. Each local region is optimized for its specific function, achieving high aesthetic quality through targeted material selection rather than uniform complexity throughout

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The interlayer film uses composite materials combining organic resin matrices with inorganic reflective particles (such as metal oxides or metallic flakes) and colored pigments or dyes. This composite approach integrates multiple material properties within a unified structure, enhancing aesthetic quality while managing overall structural complexity through material-level integration

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If multiple resin layers with different refractive indices are used to create color difference, then aesthetic quality is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecolor difference capabilityVSAvoidlayer thickness and refractive index control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes by varying the refractive indices of different resin layers and adjusting their thicknesses to optimize the color difference effect. By carefully selecting resin materials with different refractive indices and controlling layer thickness parameters, the invention achieves enhanced aesthetic quality through optical interference effects while managing manufacturing precision through systematic parameter optimization

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 film allows for visually distinct designs on opposite surfaces of laminated glass, enhancing aesthetic quality by varying the appearance based on viewing direction, while maintaining transparency and heat shielding properties.

Implementation Method 1

a color difference ΔE*ab (R) between an L*a*b* color space of reflected light of light incident from one direction and an L*a*b* color space of reflected light of light incident from an opposite direction is 0.5 or more

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

including two kinds of resin layers A and B different in refractive index

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4692017A1Interlayer film for laminated glass, and laminated glass
Publication Date: 2026.02.11 SEKISUI CHEMICAL CO LTD
  • EP4692017A1 patent drawingFigure 1~4
  • EP4692017A1 patent drawingFigure 5~8
  • EP4692017A1 patent drawingFigure 9~12

AI summary

An interlayer film for laminated glass in which a color difference ΔE*ab between an L*a*b* color space of reflected light of light incident from one direction and an L*a*b* color space of reflected light of light incident from an opposite direction is 1.2 or more.