Color Filter and Protecting Layer Geometry for High-Contrast Displays
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Solution Overview
Problem
In highly illuminated environments, ambient light reflected by display devices increases the brightness of dark states, leading to low contrast due to ineffective management of light reflection.
Innovation Solution
The display device incorporates a substrate with light-emitting units, color filter units, and a protecting layer, where the color filter units are strategically positioned to absorb ambient light, and the protecting layer's refractive index and dimensions are optimized to reduce reflection, adhering to specific geometric constraints to enhance contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional display structure is used, then the manufacturing process is simple, but the contrast ratio deteriorates in highly illuminated environments due to ambient light reflection
Solution Approach 1:
The patent introduces a protecting layer as an intermediary component between the color filter unit and the external environment. This layer has specific optical properties (refractive index n1, thickness HCF) that mediate the interaction between ambient light and the display structure, reducing harmful reflections while maintaining light extraction efficiency. The protecting layer acts as a buffer that modifies optical paths without requiring fundamental changes to the core display architecture.
Solution Approach 2:
The patent optimizes specific parameters of the protecting layer to control light reflection. By carefully selecting the refractive index (n1), thickness (HCF), and positioning (distance H from light-emitting unit), the design achieves reduced ambient light reflection. These parameter adjustments allow the system to maintain simple manufacturing while improving contrast ratio in illuminated environments.
2Object-affected harmful factors
If the protecting layer thickness is increased to reduce reflection, then ambient light reflection decreases, but light extraction efficiency may be compromised
Solution Approach 1:
The patent identifies and optimizes the thickness parameter (HCF) of the protecting layer to achieve a balance between reducing ambient light reflection and maintaining light extraction efficiency. The specific thickness range is calculated based on optical interference principles, where the layer thickness creates destructive interference for reflected ambient light while preserving constructive interference paths for emitted display light. This precise parameter control resolves the contradiction between reflection reduction and light extraction.
Solution Approach 2:
The protecting layer is designed with partial optical density - it is thick enough to reduce ambient light reflection effectively, but not so thick as to block the emitted light from the display. This partial action approach achieves sufficient reflection reduction while maintaining adequate light extraction efficiency, avoiding the extremes of either complete reflection blockage or minimal protection.
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
This configuration effectively reduces ambient light reflection while maintaining light extraction efficiency, thereby improving the contrast of the display device.
Implementation Method 1
the protecting layer has a refractive index n1
Implementation Method 2
the color filter units are strategically positioned to absorb ambient light
Data Source
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AI summary
A display device (1) includes a substrate (10), a plurality of light-emitting units (11), a plurality of color filter units (12) and a protecting layer (13). The plurality of color filter units (12) are disposed on the plurality of light-emitting units (11) and include a first color filter unit (12-1). The first color filter unit (12-1) is overlapped with a first light-emitting unit (11-1) of the plurality of light-emitting units (11). The protecting layer (13) is arranged on the plurality of color filter units (12). The display device (1) has a maximum light-emitting angle 82, the protecting layer (13) has a refractive index n1, the first color filter unit (12-1) has a width WCF along a first direction (D1), a light-emitting layer of the first light-emitting unit (11-1) has a width WL along the first direction (D1), and the first color filter unit (12-1) has a thickness HCF, a distance H is formed between the first light-emitting unit (11-1) and the first color filter unit (12-1).