Cover Window Hard Coating Layer for Impact Resistance
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Solution Overview
Problem
Conventional cover windows in display devices are prone to breaking upon external impact due to their lack of mechanical robustness, particularly the polymer films used, which have insufficient hardness and are easily delaminated from printing layers.
Innovation Solution
A cover window design incorporating a polymer film with varying hardness layers and a hard coating layer, including a first portion on the top surface, a second portion on the bottom surface of the printing layer, and a third portion between them, along with a sub-coating layer, to enhance mechanical robustness by distributing impact and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a polymer film is used as the cover window, then the display device can be made with lightweight and flexible materials, but the mechanical robustness is insufficient and the polymer film is easily broken upon external impact
Solution Approach 1:
The patent applies composite materials by combining the polymer film with a hard coating layer formed through sol-gel process. This composite structure integrates the lightweight and flexible properties of the polymer film with the high hardness and impact resistance of the inorganic hard coating layer, thereby improving mechanical robustness while maintaining the weight advantage.
Solution Approach 2:
The patent changes the physical and chemical parameters of the polymer film surface by applying a hard coating layer through sol-gel process. The coating layer undergoes chemical transformation from sol to gel state, forming an inorganic network structure with significantly higher hardness than the original polymer film, thus enhancing impact resistance.
2Strength
If a hard coating layer is applied to the polymer film, then the mechanical robustness and impact resistance are improved, but the complexity of the fabrication process increases
Solution Approach 1:
The patent merges multiple functions into a single integrated hard coating layer formation process. The sol-gel process simultaneously achieves surface modification, hard coating deposition, and chemical bonding to the polymer film in one continuous operation, reducing the need for separate processing steps and simplifying the overall fabrication process.
Solution Approach 2:
The patent uses an intermediary approach by applying the hard coating layer through a sol-gel process that acts as a mediator between the polymer film and the final hard coating structure. This intermediary process allows for controlled deposition and strong adhesion, simplifying the integration of the hard coating with the polymer substrate.
3Strength
If the hard coating layer covers the entire printing layer, then the mechanical protection is maximized, but the manufacturing precision and alignment accuracy decrease
Solution Approach 1:
The patent applies local quality by forming the hard coating layer with a controlled area that is smaller than the printing layer area. This localized coating approach focuses the hard protection precisely on the polymer film region, avoiding unnecessary coating on the printing layer edges, thereby maintaining high alignment accuracy while providing sufficient mechanical protection where needed.
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 enhanced mechanical robustness of the cover window improves its ability to withstand external impacts, thereby increasing the reliability of the display device by protecting both the polymer film and printing layer from damage.
Implementation Method 1
providing a coating solution on a top surface of the polymer film to form a hard coating layer
Data Source
AI summary
A cover window may include a polymer film, a printing layer disposed below the polymer film, and a hard coating layer. The hard coating layer may include a first portion disposed on a top surface of the polymer film and overlapping the polymer film, a second portion disposed on a bottom surface of the printing layer and overlapping the printing layer, and a third portion disposed between the first portion and the second portion. An area of the second portion may be smaller than an area of the printing layer in plan view. The cover window including the hard coating layer may have an improved mechanical robustness property and an improved reliability property.