Anti-Reflection Film Gradient Nanoparticle Distribution

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Solution Overview

Problem

Current anti-reflective films for display devices face challenges in achieving low reflectance, high light transmittance, high scratch resistance, and anti-pollution properties simultaneously, while maintaining screen sharpness, due to limitations in interlayer adhesion and particle distribution in existing multilayer structures.

Innovation Solution

An anti-reflective film comprising a hard coating layer and a low-refractive layer with a specific ratio of hollow inorganic nanoparticles and solid inorganic nanoparticles dispersed in a binder resin, where the ratio of average particle diameters is 0.26 to 0.55, and at least 70 vol% of the solid nanoparticles are positioned within 50% of the low-refractive layer's thickness from the interface with the hard coating layer, enhancing scratch resistance and anti-pollution properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a multilayer structure with hard coating layer and low-refractive layer is formed to reduce reflection, then reflectance is reduced and light transmittance is improved, but interlayer close adhesion becomes weak and scratch resistance deteriorates

Engineering Contradiction:
Improvelight transmittanceVSAvoidscratch resistance
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The patent applies local quality by creating a gradient distribution of inorganic particles within the low-refractive layer. The particle concentration and size vary through the layer thickness, with higher concentration near the hard coating layer interface and lower concentration toward the outer surface. This localized variation in particle distribution optimizes both interlayer adhesion (near the interface) and anti-pollution properties (at the surface), resolving the contradiction between light transmittance and scratch resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining organic binder resin with inorganic particles (silica, alumina, or zeolite) in specific weight ratios (inorganic particles: 1-50 parts by weight based on 100 parts by weight of binder resin). This composite structure provides both the low refractive index needed for light transmittance and the mechanical strength required for scratch resistance, while the multi-component formulation enhances interlayer adhesion.

Inventive Principle:
Principle #40Composite materials

2Strength

If inorganic particles are added to improve scratch resistance of the low-refractive layer, then scratch resistance increases, but anti-pollution property deteriorates

Engineering Contradiction:
Improvescratch resistanceVSAvoidanti-pollution property
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent resolves this contradiction through local quality by controlling the spatial distribution of inorganic particles. Particles are concentrated in the lower portion of the low-refractive layer (within 70% of the thickness from the hard coating layer interface), leaving the upper surface region relatively particle-free. This localized distribution provides scratch resistance where needed (at the interface region) while maintaining smooth anti-pollution properties at the exposed surface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies dimensionality change by transitioning from a uniform two-dimensional particle distribution to a three-dimensional gradient distribution. The particle concentration varies along the thickness dimension, creating a depth-dependent structure that simultaneously satisfies conflicting surface and interface requirements for scratch resistance and anti-pollution performance.

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

3Illumination intensity

If AG coating method is used to reduce reflection by creating uneven surface, then reflection is reduced through light scattering, but screen sharpness deteriorates

Engineering Contradiction:
Improvereflection reductionVSAvoidscreen sharpness
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical surface unevenness approach (AG coating) with an optical interference approach (AR coating). Instead of creating physical surface irregularities to scatter light, the patent uses a smooth multilayer structure with controlled refractive indices and thicknesses to achieve reflection reduction through optical interference, thereby maintaining screen sharpness while reducing reflection.

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

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 achieves low reflectance, high light transmittance, and improved scratch resistance and anti-pollution properties, while maintaining screen sharpness, through optimized particle distribution and layer structure, outperforming previous technologies in these aspects.

Implementation Method 1

a low-refractive layer containing a binder resin and hollow inorganic nanoparticles and solid inorganic nanoparticles which are dispersed in the binder resin

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

a film having a multilayer structure in which a hard coating layer (high-refractive index layer), a low-reflective coating layer, and the like, are laminated on a substrate film has been commercialized

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

the hard coating layer contains a binder resin containing a photocurable resin

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3287817B1Anti-reflection film
Publication Date: 2020.06.17 LG CHEM LTD
  • EP3287817B1 patent drawingFigure 1
  • EP3287817B1 patent drawingFigure 2
  • EP3287817B1 patent drawingFigure 3

AI summary

Disclosed herein is an anti-reflective film comprising: a hard coating layer; and a low-refractive layer containing a binder resin and hollow inorganic nanoparticles and solid inorganic nanoparticles which are dispersed in the binder resin, wherein a ratio of an average particle diameter of the solid inorganic nanoparticles to an average particle diameter of the hollow inorganic nanoparticles is 0.26 to 0.55, and wherein at least 70 vol% of the entire solid inorganic nanoparticles are present within a distance corresponding to 50% of an entire thickness of the low-refractive layer from the interface between the hard coating layer and the low-refractive layer, and an anti-reflective film comprising: a hard coating layer containing a binder resin containing a photocurable resin, and organic or inorganic fine particles dispersed in the binder resin; and a low-refractive layer containing a binder resin and hollow inorganic nanoparticles and solid inorganic nanoparticles which are dispersed in the binder resin, wherein a ratio of an average particle diameter of the solid inorganic nanoparticles to an average particle diameter of the hollow inorganic nanoparticles is 0.15 to 0.55, and wherein at least 70 vol% of the entire solid inorganic nanoparticles are present within a distance corresponding to 50% of an entire thickness of the low-refractive layer from the interface between the hard coating layer and the low-refractive layer.