Polyimide Film Composition for Flexible Display Protection

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Solution Overview

Problem

Current portable display devices face challenges in developing a protective window material that simultaneously meets optimal mechanical and optical properties, as traditional glass is fragile and non-flexible, while plastic films struggle to replace it effectively.

Innovation Solution

A composition for preparing a polyimide or poly(imide-amide) copolymer article is developed, incorporating specific structural units and pigments with a maximum absorption wavelength at 570 nanometers or more, which improves optical properties without compromising mechanical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass substrate is used for protective window, then hardness and optical properties are improved, but flexibility and impact resistance deteriorate

Engineering Contradiction:

ImprovehardnessVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent replaces rigid glass substrate with a flexible plastic film comprising a polyimide or poly(imide-amide) copolymer. This flexible film maintains optimal mechanical properties including hardness while providing necessary flexibility and impact resistance for portable display devices.

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If plastic film is used to substitute glass, then flexibility is improved, but mechanical properties and optical properties deteriorate

Engineering Contradiction:

ImproveflexibilityVSAvoidmechanical properties

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent optimizes the chemical structure of the polyimide or poly(imide-amide) copolymer by incorporating specific structural units (Chemical Formulas 1-3) with appropriate ratios. This parameter change in molecular structure enables the plastic film to achieve both flexibility and optimal mechanical properties simultaneously.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer system combining polyimide or poly(imide-amide) copolymer with specific additives including pigments (Chemical Formula 4) with maximum absorption wavelength at about 570 nanometers or more. This composite material approach enhances both mechanical characteristics and optical properties while maintaining flexibility.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If plastic film is used to substitute glass, then flexibility is improved, but optical properties deteriorate

Engineering Contradiction:

ImproveflexibilityVSAvoidoptical properties

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent controls the chemical structure parameters of the polyimide or poly(imide-amide) copolymer, specifically the ratio of structural units represented by Chemical Formulas 1-3, to optimize optical properties including transparency and yellow index while maintaining flexibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates pigments with specific absorption characteristics (Chemical Formula 4, maximum absorption wavelength at about 570 nanometers or more) to control the optical properties of the plastic film, reducing yellow index and improving overall optical performance while maintaining flexibility.

Inventive Principle:

Principle #32Color 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 solution results in a film with reduced yellow index, maintaining high tensile modulus and pencil hardness, suitable for use in flexible display devices requiring high transparency and surface hardness.

Implementation Method 1

a compound having a maximum absorption wavelength at about 570 nanometers or more in a visible radiation region

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11059954B2Composition for preparing transparent polymer film, transparent polymer film, and electronic device including same

Publication Date: 2021.07.13 SAMSUNG ELECTRONICS CO LTD

AI summary

A composition for preparing an article including a polyimide or poly(imide-amide) copolymer, the composition including (1) at least one of (i) a polyimide, a polyamic acid, or a poly(imide-amic acid) including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2; and (ii) a poly(imide-amide) copolymer, a poly(amic acid-amide) copolymer, or a poly(imide and amic acid-amide) copolymer including at least one selected from a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a structural unit represented by Chemical Formula 3, and (2) a compound having a maximum absorption wavelength at about 570 nm or more in a visible radiation region:wherein in Chemical Formulae 1 to 3, A, B, D, and E are the same as defined in the detailed description.