Anti-Reflection Substrate With Thin Absorbing Layer

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Solution Overview

Problem

Existing antireflection materials for displays require multiple layers and high-cost film-forming devices, and methods for achieving low luminous reflectance often necessitate additional antifouling layers, which are thermosetting and have low productivity.

Innovation Solution

A substrate with a light absorbing layer, low refractive index layer, and hard coating layer is formed using a few layers and active energy ray-curable resins, eliminating the need for separate antifouling coatings, and utilizing materials like titanium nitride and hollow silica to achieve low luminous reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If multiple layers of optical thin film are coated to achieve ultra-low reflection with luminous reflectance of 1.0% or less, then the antireflection performance is improved, but the manufacturing cost increases due to the need for large number of film-forming devices

Engineering Contradiction:
Improveluminous reflectanceVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions into a single layer structure. Specifically, it merges the light absorbing function and the low refractive index function into one integrated layer, eliminating the need for separate multiple layers. This is achieved by forming a light absorbing layer made of materials like titanium nitride or zirconium nitride that inherently possess both light absorption capability and suitable refractive index properties for antireflection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light absorbing layer serves multiple functions simultaneously: it absorbs light to reduce reflection, provides the necessary refractive index for optical interference, and forms the outermost surface that requires antifouling properties. This multi-functional design eliminates the need for separate dedicated layers for each function, reducing manufacturing complexity

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

2Reliability

If an antifouling layer is established on the outermost layer of the antireflective film to provide antifouling function, then the antifouling property is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improveantifouling propertyVSAvoidnumber of layers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the antifouling function with the light absorbing layer by making the light absorbing layer itself the outermost layer. Since this layer is already exposed on the surface for optical purposes, applying antifouling treatment to it provides dual functionality without adding extra layers. The hard coating layer with fluorine-containing compounds provides the antifouling property while the underlying light absorbing layer maintains optical performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light absorbing layer serves itself by being the outermost layer that directly contacts the environment. By positioning this layer at the surface and providing it with antifouling capabilities through hard coating, the structure eliminates the need for a separate dedicated antifouling layer, as the same layer performs both optical and protective functions

Inventive Principle:
Principle #25Self-service

3Reliability

If a thermosetting method is used to establish an antifouling layer on a light absorbing layer, then the antifouling property is improved, but the productivity decreases due to long heating time required

Engineering Contradiction:
Improveantifouling propertyVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the traditional thermosetting chemical bonding method with a physical adsorption method using fluorine-containing compounds. Instead of requiring high-temperature heating to form covalent bonds, the fluorine compounds are applied to the light absorbing layer and form a protective surface layer through physical interactions. This substitution of chemical bonding with physical adsorption eliminates the need for long heating cycles, significantly improving productivity while maintaining antifouling effectiveness

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 substrate achieves low luminous reflectance of 1.0% or less and excellent antifouling properties without additional antifouling layers, maintaining high transmittance and resistance to fingerprints.

Implementation Method 1

a method of using a light absorbing layer has been known

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 2

the technique of optical interference has been used in antireflection materials

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 3

active energy ray-curable resins

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4170392B1Anti-reflection substrate
Publication Date: 2025.10.15 MITSUBISHI GAS CHEM CO INC

AI summary

According to the present invention, there can be provided an antireflection substrate formed by laminating the following layers (A), (B), (C) and (D) in this order: a substrate layer (A), a hard coating layer (B), a light absorbing layer (C), and a low refractive index layer (D), formed by curing a low refractive index resin composition containing an active energy ray-curable resin, hollow silica and a fluorine compound by an active energy ray, wherein the film thickness of the light absorbing layer (C) is 1 to 20 nm.