Diamine-Based Polyimide Films for Transparent, Low-Retardation Displays

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing polyimide materials face challenges in achieving high thermal stability, transparency, and low retardation, which are essential for flexible device applications, particularly in high-temperature processes and display substrates, due to strong intermolecular forces and molecular conjugation leading to coloration and processability issues.

Innovation Solution

A diamine compound with a specific structure, represented by Chemical Formulae 1 to 5, is used as a monomer to synthesize a polyimide film with improved physical properties, including low retardation and high transparency, through polymerization with an acid dianhydride, and a polyimide precursor is developed to enhance the film's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If aromatic polyimide is used to achieve high thermal dimensional stability, then heat resistance is improved, but transparency deteriorates due to strong coloration from molecular conjugation

Engineering Contradiction:

Improveheat resistanceVSAvoidtransparency

Core Design Contradiction:

TemperatureVSIllumination intensity

Solution Approach 1:

The patent changes the chemical structure parameters of the polyimide by introducing specific diamine compounds with particular molecular configurations that reduce conjugation while maintaining thermal stability. This structural parameter modification allows simultaneous achievement of heat resistance and transparency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polyimide structure by combining different diamine and dianhydride components in specific ratios, forming a multi-component system that balances thermal properties and optical transparency through synergistic interactions between components

Inventive Principle:

Principle #40Composite materials

2Temperature

If aromatic polyimide with rigid chain structure is used to achieve thermal dimensional stability, then heat resistance is improved, but processability deteriorates due to very strong intermolecular force

Engineering Contradiction:

Improveheat resistanceVSAvoidprocessability

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent introduces local structural variations in the polyimide chain through specific diamine compounds, creating regions with different intermolecular interaction strengths. This local quality differentiation maintains overall thermal stability while providing sufficient processability in specific manufacturing stages

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent designs the polyimide structure to exhibit dynamic behavior during processing, where intermolecular forces can be temporarily overcome under processing conditions and then re-establish to maintain thermal stability during service, enabling both processability and heat resistance

Inventive Principle:

Principle #15Dynamics

3Temperature

If conventional polyimide is used to ensure stability during high-temperature processes, then heat resistance is improved, but retardation value increases causing deterioration of display quality

Engineering Contradiction:

Improveheat resistanceVSAvoidretardation value

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent modifies the molecular parameters of the polyimide by selecting specific diamine compounds with particular ring structures and substituent patterns, changing the birefringence characteristics while maintaining thermal stability, thereby achieving low retardation values suitable for display applications

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 diamine compound enables the production of a highly transparent polyimide film with low retardation values, ensuring excellent heat resistance and transparency, suitable for flexible devices and display substrates, while maintaining stability during high-temperature processes.

Implementation Method 1

Methodology Applied

Scientific EffectPolymerization:

Implementation Method 2

a polyimide film formed on the conveyance board does not undergo thermal decomposition by hydrolysis even during the high temperature process and should satisfy high heat resistance

Methodology Applied

Scientific EffectThermal stability:

Data Source

PatentUS12410281B2Diamine compound, polyimide precursor and polyimide film using the same, and use thereof

Publication Date: 2025.09.09 SK INNOVATION CO LTD

AI summary

Provided a diamine compound, a polyimide precursor and a polyimide film using the same, and a use thereof. The diamine compound may be very useful as a monomer for manufacturing a polyimide film having excellent transparency, high heat resistance, and low retardation.