Polyamide-imide Resin for Flexible Displays
Solution Overview
Problem
Polyamide-imide resins used in flexible displays face inconsistencies in manufacturing methods, leading to variations in performance properties such as transparency and birefringence, which are essential for clear image production, especially when replacing glass substrates.
Innovation Solution
Development of polyamide-imide materials with specific molecular structures and properties, including tetravalent and divalent moieties, to achieve high tensile modulus, glass transition temperature, and optical transparency, which are optimized through precise monomer and co-monomer ratios and processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If polyamide-imide resin is used as an alternative to glass substrate in display elements, then flexibility and lightweight properties are improved, but manufacturing consistency and performance uniformity deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight distribution (peak molecular weight ≥50 kDa, weight average molecular weight ≥50 k) and compositional ratios of monomers and co-monomers in the polyamide-imide resin. These parameter optimizations ensure consistent optical properties (transparency ≥85% at 550 nm, birefringence ≤0.03) and mechanical properties (tensile modulus ≥3.5 GPa, elongation at break ≤15%) across manufacturing batches, resolving the manufacturing consistency issue while maintaining the lightweight advantage
Solution Approach 2:
The patent uses composite material principles by creating a polyamide-imide resin system that combines multiple functional components: imide groups for heat resistance, aromatic moieties for mechanical strength, and controlled molecular weight distribution for optical consistency. This composite molecular structure achieves both the desired flexibility/lightweight properties and manufacturing uniformity
2Weight of moving object
If polyamide-imide resin is used as an alternative to glass substrate in display elements, then flexibility and lightweight properties are improved, but optical transparency and birefringence control deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the optical parameters of the polyamide-imide resin: transparency ≥85% at 550 nm, birefringence ≤0.03, and yellow index ≤4.0. These parameter specifications ensure that the resin maintains excellent optical clarity suitable for display applications while preserving the lightweight and flexible advantages over glass substrates
3Weight of moving object
If polyamide-imide resin is used as an alternative to glass substrate in display elements, then flexibility is improved, but mechanical strength and dimensional stability deteriorate
Solution Approach 1:
The patent applies parameter changes by specifying minimum mechanical property thresholds for the polyamide-imide resin: tensile modulus ≥3.5 GPa, tensile strength ≥60 MPa, elongation at break ≤15%, and glass transition temperature ≥180°C. These parameter optimizations ensure the resin achieves sufficient mechanical strength and dimensional stability for display applications while maintaining flexibility and lightweight characteristics
Data Source
AI summary
A polyamide-imide material comprises an amidophenyl-ethyl-imide moiety or alternatively an imidophenyl-ethyl-amide moiety as depicted in formulas (I) or (II) in the disclosure. The polyamide-imide material can have selected mechanical properties, such as a tensile modulus between at least 3.5 GPa and at least 7.8 GPa, a glass transition temperature between at least 180° C. and at least 305° C., an elongation at break of a film of the polyamide-imide material having a thickness of 25 micrometer (±5 micrometer) of not more than 15%, or a folding endurance of the film over a pin having a radius of 1 mm between at least 10,000 folds and at least 1,000,000 folds. The polyamide-imide film can have high transparency of visible light, a low yellow index, and a low haze.