OLED Inorganic Encapsulation Adhesion via Substrate Structuring
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Solution Overview
Problem
Conventional organic light-emitting diodes (OLEDs) face issues with delamination under extreme conditions, such as thermal cycling and moisture exposure, due to insufficient adhesion of encapsulation layers, leading to failure in reliability and light coupling efficiency.
Innovation Solution
An optoelectronic component with an inorganic encapsulation layer directly contacting a structured substrate surface, where the structuring increases the surface roughness to enhance adhesion and light coupling, using a planar substrate with inorganic material and optional organic layers for improved adhesion and light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation layers are used in OLEDs, then the device can be manufactured with standard processes, but the adhesion force is insufficient under extreme conditions leading to delamination and failure
Solution Approach 1:
The patent changes the physical-chemical parameters of the encapsulation layer by using inorganic materials (such as silicon oxide, silicon nitride, or aluminum oxide) deposited via atomic layer deposition (ALD) instead of conventional organic encapsulation layers. This material substitution fundamentally alters the adhesion properties, providing superior thermal stability and adhesion strength under extreme conditions while maintaining compatibility with existing OLED manufacturing processes.
Solution Approach 2:
The patent employs composite encapsulation structures combining multiple inorganic layers with different materials (e.g., alternating silicon oxide and silicon nitride layers) to achieve synergistic effects. The different inorganic materials provide complementary properties including enhanced adhesion, barrier performance, and stress management, creating a multi-functional encapsulation system that outperforms single-material approaches.
2Productivity
If smooth OLED layers are used, then the manufacturing process is simpler, but light coupling efficiency is low due to total internal reflection
Solution Approach 1:
The patent introduces periodic undulations in the encapsulation layer that extend in the vertical dimension, creating a three-dimensional surface profile with peaks and valleys. This vertical dimensionality change disrupts the planar waveguide structure, enabling light to escape at different angles and improving coupling efficiency without requiring lateral structuring that would complicate manufacturing.
Solution Approach 2:
The patent employs curved, undulating interfaces between encapsulation layers rather than flat planar interfaces. The periodic curvature of the undulations creates varying normal vectors across the interface, which modifies light propagation paths and reduces total internal reflection, thereby enhancing light extraction efficiency.
3Adaptability or versatility
If flexible OLEDs are bent, then the device achieves desired flexibility, but delamination occurs between layers leading to total failure
Solution Approach 1:
The patent changes the mechanical parameters of the encapsulation system by using inorganic materials with appropriate elastic moduli and thermal expansion coefficients that match the flexible substrate and OLED layers. This parameter matching reduces stress concentration during bending, preventing delamination while maintaining flexibility.
Solution Approach 2:
The patent considers thermal expansion coefficients of different materials in the OLED stack when selecting inorganic encapsulation materials. By matching thermal expansion properties, the patent minimizes differential stress during temperature cycling and bending operations, preventing layer separation and maintaining structural integrity under extreme conditions.
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 significantly reduces the risk of delamination and enhances light coupling efficiency, improving the reliability and performance of OLEDs under stringent conditions.
Implementation Method 1
The inorganic encapsulation layer is formed on or above the optically active layer structure and the surface of the substrate in the predefined region
Implementation Method 2
The structuring is configured to increase the roughness of the surface
Data Source
AI summary
In various embodiments, an optoelectronic component is provided. The optoelectronic component includes an optically active layer structure on a surface of a planar substrate. The surface in a predefined region is free of optically active layer structure. The optoelectronic component further includes an encapsulation structure having an inorganic encapsulation layer. The inorganic encapsulation layer is formed on or above the optically active layer structure and the surface of the substrate in the predefined region. The inorganic encapsulation layer at least in the predefined region is formed in direct contact with the surface of the substrate. The surface of the substrate at least in the predefined region includes a structuring. The structuring is configured to increase the roughness of the surface. The substrate at least in the predefined region at the surface thereof includes or is formed from an inorganic material.