Polyimide Cover Window Film for Flexible Displays
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Solution Overview
Problem
Current polyimide films for cover windows face challenges in achieving both excellent optical and mechanical properties without compromising colorless and transparent properties, as they often suffer from mura phenomena and reduced visibility due to light distortion, especially in flexible display devices.
Innovation Solution
A composition for forming a polyimide film using a mixed solvent of amide-based and hydrocarbon-based solvents, with specific structural units derived from dianhydrides and diamines, is applied to a substrate, followed by curing, to inhibit intermolecular packing density and adjust crystallinity, resulting in a film with improved optical and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating layer is laminated on a substrate to impart various physical properties, then mechanical properties such as hardness and rigidity are improved, but diffuse reflection of light is caused and optical stain occurs to deteriorate visibility
Solution Approach 1:
The patent changes the chemical composition parameters of the polyimide film by using specific dianhydrides (BPDA, 6FDA) and diamines (TFMB, DDS) in controlled ratios, and by adjusting the solvent system composition (amide-based and hydrocarbon-based solvents in specific proportions), to achieve a film that provides mechanical reinforcement without causing optical distortion or stain
Solution Approach 2:
The patent creates a composite material system combining polyimide polymer with specific solvent additives and curing agents, where the composite formulation enables the film to simultaneously achieve mechanical strength and optical clarity by controlling the interaction between components during film formation and curing
2Temperature
If polyimide film is used to replace tempered glass for cover window, then heat resistance and chemical resistance are improved, but optical properties such as transparency and visibility may be compromised
Solution Approach 1:
The patent optimizes the molecular structure parameters of the polyimide film by selecting specific dianhydride and diamine combinations and controlling their molecular weight and structural units, while adjusting solvent content and curing conditions, to achieve a film that maintains high heat resistance while preserving excellent optical transparency and visibility
Solution Approach 2:
The patent introduces specific functional groups and structural units at local positions within the polyimide chain to enhance optical properties while maintaining overall heat resistance, creating regions with different properties that collectively achieve both thermal stability and optical clarity
3Adaptability or versatility
If polyimide film is used for flexible display devices, then flexibility is improved, but mechanical properties such as hardness and rigidity may be reduced
Solution Approach 1:
The patent adjusts the crystallinity and crosslinking density parameters of the polyimide film through controlled curing conditions and solvent selection, creating a film that achieves the right balance between flexibility for flexible displays and mechanical strength for durability
Solution Approach 2:
The patent creates a dynamically adaptable film structure where the polyimide can flex and deform elastically while maintaining its mechanical integrity through controlled molecular mobility and crosslinking, enabling the film to accommodate flexible display bending without permanent deformation or loss of strength
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 effectively reduces light distortion and maintains excellent mechanical properties, such as modulus and elongation at break, while ensuring high transparency and visibility, making it suitable for flexible display devices with reduced mura phenomena and improved reliability.
Implementation Method 1
a mixed solvent of an amide-based solvent and a hydrocarbon-based solvent
Implementation Method 2
inhibit intermolecular packing density and adjust crystallinity
Implementation Method 3
applied to a substrate, followed by curing
Data Source
AI summary
Provided are a composition for forming a polyimide film for a cover window which may satisfy performance required for an advanced cover window, a method for preparing the same, and a use thereof. According to an implementation, a polyimide film for a cover window, which has excellent visibility without optical stain while colorless and transparent optical properties were not deteriorated and has excellent heat resistance and mechanical properties, and thus, is for use in optical applications, may be provided. In addition, a polyimide film for a cover window according to an implementation may be useful in various display devices.