Multi-Layer Anti-Reflection Stack for Display Visibility
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Solution Overview
Problem
Display devices face challenges in improving external visibility and display quality due to inadequate control over external light reflectance.
Innovation Solution
A display device structure incorporating an anti-reflection layer with specific refractive index layers, including a first passivation layer, refractive layers, and an outer refractive layer, designed to control external light reflectance by utilizing materials like silicon oxynitride, silicon nitride, and silica, and structured to dissipate light through destructive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional single-layer anti-reflection coating is used, then the structure is simple, but external light reflectance cannot be sufficiently controlled to improve visibility
Solution Approach 1:
The anti-reflection layer is divided into multiple functional sub-layers: a first passivation layer (oxide) for protection, a first refractive layer (silicon oxynitride) with refractive index 1.60-1.69, a second refractive layer (silicon nitride) with refractive index 1.70-2.10, and an outer refractive layer (fluorine-substituted material) with refractive index 1.23-1.40. This segmentation allows each layer to contribute specific optical properties for controlling external light reflectance while improving visibility.
Solution Approach 2:
The anti-reflection layer uses a composite structure combining different materials with specific refractive indices: silicon oxynitride, silicon nitride, and fluorine-substituted organic/inorganic hybrid materials. This composite approach enables precise control over light reflection and transmission characteristics to enhance external visibility while managing the increased structural complexity.
2Illumination intensity
If multiple refractive layers with different refractive indices are added to control external light reflectance, then external visibility is improved, but the manufacturing process becomes more complex
Solution Approach 1:
Each layer is designed with specific refractive index ranges (first refractive layer: 1.60-1.69, second refractive layer: 1.70-2.10, outer refractive layer: 1.23-1.40) and controlled thicknesses (50-150 nm for refractive layers, 200-300 nm for first passivation layer, 20-50 nm for second passivation layer). These parameter specifications enable optimization of light reflection control while providing guidance for manufacturing processes.
Solution Approach 2:
The passivation layers (first and second passivation layers containing oxide) serve as intermediary protective layers between the refractive layers and the underlying display layer. These intermediary layers protect the refractive layers while maintaining the optical interference properties needed for visibility enhancement, simplifying the overall manufacturing by providing protective barriers.
3Reliability
If the anti-reflection layer structure is optimized for light interference control, then display quality reliability is improved, but the layer thickness control requirements become more stringent
Solution Approach 1:
The refractive layers are designed with thicknesses in the range of 50-150 nm, which provides sufficient optical interference control for display quality enhancement without requiring extremely precise thickness control. The passivation layers are designed with thicker ranges (200-300 nm for first passivation, 20-50 nm for second passivation) to provide adequate protection while being more tolerant to manufacturing variations, thus achieving reliability without excessively stringent precision requirements.
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 enhances visibility and display quality by effectively managing external light reflectance, reducing glare, and maintaining the phase of light, thereby improving the overall performance of the display device.
Implementation Method 1
at least a portion of the external light may be reflected at an outer surface of the outer refractive layer or at an interface between the second passivation layer and the second refractive layer, and may be provided as first reflected light of which a phase is inverted with respect to a phase of the at least a portion of the external light, and at least another portion of the external light may be reflected at an interface between the first refractive layer and the second refractive layer or at an interface between the first passivation layer and the first refractive layer and may be provided as second reflected light of which a phase is maintained with respect to a phase of the at least another portion of the external light. at least a portion of the first reflected light and at least a portion of the second reflected light may dissipate by destructive interference with each other.
Data Source
AI summary
A display device includes: a display layer; an overcoat layer disposed on the display layer and including an organic material; and an anti-reflection layer disposed on the overcoat layer. The anti-reflection layer includes: a first passivation layer; a first refractive layer disposed on the first passivation layer and having a first refractive index; a second refractive layer disposed on the first refractive layer and having a second refractive index; a second passivation layer disposed on the second refractive layer; and an outer refractive layer disposed on the second passivation layer and having an outer refractive index. The first passivation layer and the second passivation layer include an oxide. The first refractive index is less than the second refractive index, and the outer refractive index is less than the first refractive index.