Cover Window Anti-Reflective Coating for Display Devices
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Solution Overview
Problem
Existing display device cover windows struggle to balance reflectance reduction and wear resistance while effectively absorbing external shock.
Innovation Solution
A cover window configuration that includes a window layer, a first refractive layer with stishovite nano-polycrystals, a second refractive layer, an adhesive layer, a cover layer, and a light blocking layer, optimized for refractive indices, thicknesses, and deposition methods to achieve low reflectance and enhanced wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional cover window structure is used, then the manufacturing process is simple, but the reflectance is high and wear resistance is insufficient
Solution Approach 1:
The patent applies composite materials by stacking multiple layers with different refractive indices (first refractive layer with 1.7-1.9, second refractive layer with 1.3-1.5, adhesive layer with 1.4-1.6, and cover layer with 1.2-1.4) to create an anti-reflective coating system. This multi-layer composite structure reduces reflectance to 0.2-0.5% while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling the refractive index range of each layer (first refractive layer: 1.7-1.9, second refractive layer: 1.3-1.5, adhesive layer: 1.4-1.6, cover layer: 1.2-1.4) and thickness parameters to optimize optical performance. This systematic parameter optimization achieves minimal reflectance while maintaining practical manufacturability.
2Ease of manufacture
If a conventional cover window structure is used, then the manufacturing process is simple, but wear resistance is low
Solution Approach 1:
The patent employs composite materials with a multi-layer structure where each layer contributes specific properties: the first refractive layer provides optical control, the second refractive layer enhances anti-reflective performance, the adhesive layer ensures strong bonding, and the cover layer provides wear resistance. This composite approach achieves superior wear resistance without significantly complicating the manufacturing process.
Solution Approach 2:
The patent applies local quality by assigning different functional properties to different layers: the cover layer (1.2-1.4 refractive index) specifically provides wear resistance and protection, while internal layers focus on optical performance. This localized functional assignment optimizes overall reliability without requiring complete redesign of the entire structure.
3Device complexity
If a single-layer refractive coating is used, then the structure is simple, but reflectance cannot be reduced below 0.5%
Solution Approach 1:
The patent uses composite materials with four distinct layers having progressively decreasing refractive indices (1.7-1.9, 1.3-1.5, 1.4-1.6, 1.2-1.4) to achieve reflectance reduction to 0.2-0.5%. This multi-layer composite structure outperforms single-layer coatings while maintaining reasonable structural complexity through systematic material selection.
Solution Approach 2:
The patent transitions from a single-layer to a multi-layer dimensional structure, adding vertical layering to achieve progressive refractive index transitions. This dimensional approach enables gradual optical impedance matching, reducing reflectance more effectively than single-layer solutions while keeping each individual layer relatively simple.
4Object-affected harmful factors
If the first refractive layer has high refractive index (1.7-1.9), then reflectance is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent systematically controls refractive index parameters within specific ranges (first refractive layer: 1.7-1.9, second refractive layer: 1.3-1.5, adhesive layer: 1.4-1.6, cover layer: 1.2-1.4) to balance optical performance and manufacturability. These parameter specifications provide clear manufacturing targets while achieving reflectance reduction to 0.2-0.5% without excessive precision requirements.
Solution Approach 2:
The patent uses composite materials where the high refractive index first layer (1.7-1.9) is combined with subsequent layers of progressively lower refractive indices. This composite structure distributes the optical control function across multiple layers, reducing the manufacturing precision burden on any single layer while maintaining overall reflectance performance.
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 proposed cover window design achieves a reflectance of 0.2% to 0.5% and improved wear resistance by effectively absorbing external shock, making it suitable for display devices without polarizing layers.
Implementation Method 1
a first refractive layer disposed on one surface of the window layer, a second refractive layer disposed on the first refractive layer
Implementation Method 2
the first refractive layer may have a refractive index of 1.7 to 1.9... the cover window may have a reflectance measured in a specular component included (SCI) mode of 0.2% to 0.5%
Implementation Method 3
the first refractive layer may be formed using a vapor deposition method of one or more of physical vapor deposition (PVD), electron beam (EB) deposition
Implementation Method 4
electron beam (EB) deposition, ion assisted deposition-electron beam (IAD-EB), laser ablation, vacuum arc deposition
Implementation Method 5
laser ablation
Data Source
AI summary
According to an embodiment of the disclosure, a cover window may include a window layer, a first refractive layer disposed on one surface of the window layer, a second refractive layer disposed on the first refractive layer, a cover layer disposed on the second refractive layer, an adhesive layer disposed between the cover layer and the second refractive layer, and a light blocking layer disposed on another surface of the window layer, and the first refractive layer may have a refractive index of 1.7 to 1.9.