Polyimide Films for Flexible Displays with Low Optical Retardation
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Solution Overview
Problem
There is a need for polymer materials with improved properties suitable for use in electronic devices, particularly in flexible display applications where polyimides face challenges due to birefringence and optical retardation, limiting their performance in OLEDs and other electronic displays.
Innovation Solution
Development of a polyanhydride with specific structural features, leading to the creation of polyamic acid and polyimide films with improved thermal stability, mechanical toughness, and reduced optical retardation, which can serve as a flexible replacement for glass in electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyimides are used as flexible substrates in electronic displays, then thermal stability and mechanical toughness are improved, but optical retardation increases due to birefringence
Solution Approach 1:
The patent modifies the chemical structure of polyimide by incorporating specific aromatic diamine monomers with particular substituent patterns (e.g., methyl groups at specific positions, fluorine substitutions) to alter the polymer chain conformation and reduce birefringence while preserving thermal stability
Solution Approach 2:
The invention creates composite polyimide structures by combining different aromatic diamine and dianhydride components to achieve a material that simultaneously provides thermal stability and reduced optical retardation properties
2Strength
If polyimide films are used in flexible display applications, then mechanical toughness is improved, but display performance deteriorates due to optical retardation
Solution Approach 1:
The patent optimizes the molecular structure of polyimide by selecting specific aromatic diamine monomers with controlled substituent positions and types to reduce optical retardation while maintaining the mechanical toughness required for flexible displays
3Weight of moving object
If conventional polyimides are used as glass replacement, then flexibility and light weight are improved, but optical properties deteriorate due to birefringence
Solution Approach 1:
The invention modifies the polyimide molecular structure through specific monomer selection and substitution patterns to reduce birefringence and improve optical properties while preserving the light weight advantage for flexible displays
Data Source
AI summary
Disclosed is a polyanhydride having Formula Iwhere A isIn Formula I: R1 and R2 are the same or different at each occurrence and are F, CN, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, silyl, siloxy, unsubstituted or substituted hydrocarbon aryl, unsubstituted or substituted heteroaryl, or unsubstituted or substituted aryloxy; R3 and R4 are the same or different and are A3, A4, H, F, CN, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, silyl, siloxy, unsubstituted or substituted hydrocarbon aryl, unsubstituted or substituted heteroaryl, or unsubstituted or substituted aryloxy; R5 and R6 are the same or different and are H, F, CN, alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, silyl, siloxy, unsubstituted or substituted hydrocarbon aryl, unsubstituted or substituted heteroaryl, and unsubstituted or substituted aryloxy; R8 is selected from the group consisting of alkyl, silyl, unsubstituted or substituted hydrocarbon aryl, or unsubstituted or substituted heteroaryl; c and d are the same or different and are an integer from 0 to the maximum available; m and n are the same or different and are 0 or 1; A1 to A4 are the same or different and have the formulasingle dashed lines between two rings indicate that the rings are joined by a single bond or fused together at any available position; L is a bond or a hydrocarbon aryl; and at least two A groups are present.