Sub-Inorganic Layer Encapsulation for Display Light Extraction
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Solution Overview
Problem
Current display devices face challenges in achieving improved reliability and light efficiency, particularly in the design of self-light emitting display devices which require enhanced encapsulation and color conversion techniques to maintain performance and longevity.
Innovation Solution
The proposed display device incorporates a thin-film encapsulation layer with specific inorganic and organic layers, a wavelength conversion pattern, and a capping layer, along with a color filter, to enhance light efficiency and reliability by preventing moisture and oxygen penetration and optimizing light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer inorganic encapsulation layer is used, then the device structure is simple and manufacturing is easier, but moisture and oxygen penetration increases reducing reliability
Solution Approach 1:
The encapsulation layer is divided into multiple inorganic sub-layers (first inorganic layer, second inorganic layer, third inorganic layer) with different refractive indices, where each sub-layer provides partial barrier function against moisture and oxygen penetration, collectively achieving superior encapsulation reliability compared to a single-layer structure
Solution Approach 2:
The encapsulation system combines multiple inorganic materials with different refractive indices (e.g., SiO2, SiOxNy, Si3N4) to create a composite barrier structure that leverages the complementary properties of each material to prevent moisture and oxygen penetration more effectively than any single material alone
2Productivity
If a single inorganic layer is used in the encapsulation, then manufacturing precision requirements are lower, but light extraction efficiency is reduced due to internal reflection
Solution Approach 1:
Different inorganic sub-layers are assigned different refractive indices optimized for their specific positions in the stack: the first inorganic layer has a lower refractive index to reduce reflection at the interface with the organic light-emitting layer, while subsequent layers have progressively higher refractive indices to maximize light extraction efficiency at each interface
Solution Approach 2:
The refractive index parameter is systematically varied across the inorganic sub-layers to create a gradient structure that optimizes light extraction at each interface, transforming the uniform parameter approach into a controlled parameter variation strategy that enhances overall light extraction efficiency
3Illumination intensity
If conventional encapsulation without sub-inorganic layers is used, then device complexity is low, but light efficiency and luminance performance are insufficient
Solution Approach 1:
The encapsulation structure transitions from a conventional single-layer or simple multi-layer configuration to a three-dimensional stacked architecture with alternating inorganic and organic layers, where each inorganic layer is further divided into sub-layers with different refractive indices, creating a complex spatial arrangement that maximizes light extraction in multiple directions
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 improves light extraction efficiency, reduces internal reflection, and enhances the display's luminance and contrast, thereby extending the device's lifespan and maintaining high performance.
Implementation Method 1
the first inorganic layer includes two sub-inorganic layers having different refractive indices
Data Source
AI summary
A display device includes a base; a light emitting element on the base; a capping layer on the light emitting element; a thin-film encapsulation layer including a first inorganic layer on the capping layer, an organic layer on the first inorganic layer, and a second inorganic layer on the organic layer; and a wavelength conversion pattern on the thin-film encapsulation layer and overlapping the light emitting element, wherein the first inorganic layer includes two sub-inorganic layers having different refractive indices.