Self-Supporting Transparent Film for Display Devices

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Solution Overview

Problem

Existing transparent films for flat panel displays require substrates like glass fiber cloth, limiting their flexibility and increasing costs, while also falling short in heat resistance and wide applicability.

Innovation Solution

A self-supporting transparent film with a single or multilayer structure made from a cured resin composition comprising alicyclic epoxy resin, a polyol compound, and an acid generator, optimized for thickness, refractive index matching, and crosslink density to enhance heat resistance and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If glass fiber cloth is used as a substrate for transparent films, then heat resistance and structural stability are improved, but flexibility and transparency deteriorate

Engineering Contradiction:
Improveheat resistanceVSAvoidflexibility
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The invention extracts and eliminates the glass fiber cloth substrate from the transparent film structure, creating a substrate-free self-supporting film. This removes the source of brittleness and poor flexibility while maintaining heat resistance through the cured resin composition itself, which achieves Tg of 80°C or higher without requiring a rigid substrate

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a composite resin composition comprising multiple components (epoxy resin, polyol compound, and optionally imide resin) that work together to achieve both heat resistance and flexibility. The specific formulation with controlled molecular weight and hydroxyl group value of the polyol compound creates a self-supporting structure that replaces the need for glass fiber cloth while maintaining thermal stability

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If glass fiber cloth is used as a substrate, then structural stability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The invention removes the expensive glass fiber cloth substrate, eliminating material costs and simplifying the manufacturing process. The self-supporting cured resin composition provides sufficient structural stability on its own, reducing overall manufacturing cost while maintaining product performance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the formulation parameters of the resin composition, specifically controlling the molecular weight and hydroxyl group value of the polyol compound, to achieve self-supporting properties without additional substrates. This parameter optimization enables the film to stand alone structurally, eliminating substrate requirements and reducing manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If the resin composition is optimized for transparency by matching refractive indices, then optical characteristics are improved, but heat resistance may be compromised

Engineering Contradiction:
ImprovetransparencyVSAvoidheat resistance
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The invention combines multiple resin components with complementary properties: the epoxy resin provides structural backbone, the polyol compound with specific molecular weight and hydroxyl group value contributes to flexibility and transparency, and the optional imide resin enhances heat resistance. This composite approach allows simultaneous optimization of optical and thermal properties

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters of the polyol compound (molecular weight and hydroxyl group value) to achieve the right balance between transparency and heat resistance. The controlled hydroxyl group value ensures proper crosslinking density for heat resistance while maintaining optical clarity, resolving the trade-off between these two properties

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 achieves excellent transparency, heat resistance, and flexibility, reducing production costs and expanding application possibilities without the need for a substrate, making it suitable for various display technologies.

Implementation Method 1

a cured product of a resin composition comprising an alicyclic epoxy resin (A), a polyol compound (B), and an acid generator (C)

Methodology Applied
Scientific EffectCrosslinking reaction: Chemical Bonding

Implementation Method 2

the resin composition comprises an alicyclic epoxy resin (A), a polyol compound (B), and an acid generator (C)

Methodology Applied
Scientific EffectPolymerization: Chemical Bonding

Data Source

PatentEP3434708B1Film and image display device
Publication Date: 2022.09.07 TOPPAN HOLDINGS INC
  • EP3434708B1 patent drawingFigure 1~2
  • EP3434708B1 patent drawingFigure 3
  • EP3434708B1 patent drawing

AI summary

A film is provided as a self-supporting film which can be produced inexpensively and is excellent in transparency, heat resistance and flexibility. The film of the present invention is a self-supporting film having a single layer structure and is made of a cured product of a resin composition comprising an alicyclic epoxy compound (A), a polyol compound (B) and an acid generator (C). The amount ratio of the alicyclic epoxy compound (A) to the total amount of the alicyclic epoxy compound (A) and the polyol compound (B) is within a range of from 50 to 80 mass%, and the amount of the acid generator (C) is within a range of from 0.05 to 0.5 parts by mass per 100 parts by mass of the alicyclic epoxy compound (A) and the polyol compound (B) in total.