Plastic Window Hard Coating for Flexible Display Durability
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Solution Overview
Problem
Conventional display devices using glass or tempered glass are prone to breakage from external impacts and are not suitable for flexible display devices, while plastic window members offer improved impact resistance but may lack durability and flexibility.
Innovation Solution
A display device with a plastic window and multiple hard coating layers, including a second hard coating layer with anti-fingerprint properties and a specific surface water contact angle, providing enhanced durability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass or tempered glass is used as a window member, then scratch resistance and surface hardness are improved, but impact resistance and flexibility deteriorate
Solution Approach 1:
The patent uses a composite structure consisting of a plastic window member combined with multiple hard coating layers. The plastic base material (such as PET or PC) provides flexibility and impact resistance, while the hard coating layers (applied through processes like PECVD or sputtering) provide scratch resistance and surface hardness. This composite approach resolves the contradiction by combining materials with complementary properties.
2Reliability
If plastic materials are used as window members, then impact resistance and flexibility are improved, but surface hardness and scratch resistance deteriorate
Solution Approach 1:
The patent applies multiple hard coating layers on the plastic window member to compensate for the lower surface hardness of plastic materials. The hard coatings (such as silicon oxide, silicon nitride, or diamond-like carbon) provide the necessary scratch resistance while the plastic substrate maintains impact resistance and flexibility.
Solution Approach 2:
The patent applies different hard coating layers with different properties at different locations or depths. The first hard coating layer provides initial protection, the second hard coating layer enhances surface hardness, and the third hard coating layer (on the inner surface) provides additional scratch resistance. This layered approach with differentiated local properties resolves the contradiction between plastic's inherent flexibility and the need for surface hardness.
3Strength
If multiple hard coating layers are applied on a plastic window member, then surface hardness and scratch resistance are improved, but device complexity increases
Solution Approach 1:
The patent optimizes the parameters of the hard coating process, such as controlling the thickness of each layer (first layer: 50-200 nm, second layer: 200-500 nm, third layer: 50-200 nm) and selecting appropriate deposition methods (PECVD, sputtering). By standardizing these parameters, the manufacturing process becomes more controllable and less complex despite having multiple layers.
Solution Approach 2:
The hard coating layers serve multiple functions simultaneously: they provide scratch resistance, enhance surface hardness, improve durability, and maintain optical transparency. The anti-fingerprint layer on the inner surface adds another function (easy cleaning) without requiring a separate component. This multi-functionality reduces the need for additional separate components, thereby managing device complexity.
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 results in a display device with improved durability and flexibility, allowing for a slim profile and effective protection against external impacts and bending, while maintaining anti-fingerprint properties.
Implementation Method 1
a second hard coating layer provided on the first hard coating layer, wherein a surface water contact angle of the second hard coating layer is in a range of 90 degrees to 117 degrees
Data Source
AI summary
A display device includes a display panel and a window member provided on the display panel. The window member includes a plastic window, a first hard coating layer provided on the plastic window, and a second hard coating layer provided on the first hard coating layer. A surface water contact angle of the second hard coating layer may be in a range of 90 degrees to 117 degrees.