Flexible Display Cover Window Coating for Fold Damage Protection
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Solution Overview
Problem
Existing flexible organic light-emitting display apparatuses face challenges in protecting the display surface from external damage while maintaining bendability and foldability, necessitating improvements in the window film material and thickness to enhance durability.
Innovation Solution
A foldable, flexible display apparatus is designed with a window film made of transparent plastic materials like polyethylene terephthalate, polymethylmethacrylate, or polycarbonate, combined with a coating layer of a siloxane-polymer hybrid formed through a condensation reaction of organoalkoxysilane and organosilanediol, and an adhesive layer for bonding, ensuring elasticity and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the window film is made thinner to improve flexibility and bendability, then the display apparatus becomes more foldable, but the protection against physical damage deteriorates
Solution Approach 1:
The patent applies composite materials by combining a transparent plastic film (polyethylene terephthalate, polymethylmethacrylate, polycarbonate, or polyimide) with a coating layer containing siloxane-polymer hybrid formed through condensation reaction of organoalkoxysilane and organosilanediol. This composite structure provides both flexibility for bending/folding and enhanced protection against physical damage, resolving the contradiction between adaptability and strength.
Solution Approach 2:
The patent changes the material parameters by specifying a modulus of elasticity of about 6.3 gigapascals or more for the transparent plastic film and using a coating layer with specific thickness (about 45% or more of the sum of thicknesses). These parameter optimizations enable the window film to maintain both flexibility and protection capabilities.
2Strength
If the window film is made thicker to improve protection against physical damage, then durability is improved, but the flexibility and bendability deteriorate
Solution Approach 1:
The composite structure of transparent plastic film combined with siloxane-polymer hybrid coating layer provides a solution where the coating layer compensates for the reduced flexibility of thicker films. The coating layer's elastic properties maintain overall flexibility while the increased film thickness provides enhanced protection.
Solution Approach 2:
The patent optimizes the thickness parameter by specifying that the sum of thicknesses of the window film and coating layer should be about 120 micrometers or more, with the coating layer comprising about 45% or more of this sum. This parameter optimization ensures both protection and flexibility are achieved.
3Strength
If a rigid coating layer is applied to protect the window film, then protection against physical damage is improved, but the bendability and foldability deteriorate
Solution Approach 1:
The patent changes the material properties of the coating layer by using siloxane-polymer hybrid formed through condensation reaction, which provides elastic properties. This allows the coating layer to be sufficiently thick for protection (about 45% or more of total thickness) while maintaining flexibility during bending and folding operations.
Solution Approach 2:
The combination of transparent plastic film with siloxane-polymer hybrid coating creates a composite structure where the coating layer's elastic characteristics compensate for any rigidity, maintaining overall bendability while providing enhanced protection against physical damage.
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 provides enhanced protection against physical damage while maintaining flexibility, allowing the display apparatus to be bent or folded without compromising its functionality.
Implementation Method 1
an adhesive layer between the window film and the display side of the flexible display panel, and configured to have elasticity and bond the window film and the flexible display panel to each other
Implementation Method 2
a coating layer on the window film, and configured to be transparent and to protect the window film from physical damage thereto; The coating layer may include a siloxane-polymer hybrid which is a product of a condensation reaction of an organoalkoxysilane and an organosilanediol
Data Source
AI summary
A foldable, flexible display apparatus includes a flexible display panel which displays an image and includes a display side on which the image is displayed and of which portions thereof face each other in a folded state of the flexible display apparatus; a cover window on the display side of the flexible display panel and including: a window film comprising a transparent plastic film having a modulus of elasticity of about 6.3 gigapascals or more; and a coating layer on the window film, and configured to be transparent and to protect the window film from physical damage thereto; and an adhesive layer between the window film and the display side of the flexible display panel, and configured to have elasticity and bond the window film and the flexible display panel to each other.