Flexible OLED Substrate Through-Hole Humidity Barrier via SVI
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Solution Overview
Problem
Existing organic light emitting display apparatuses face challenges in preventing humidity and oxygen infiltration, which can damage thin film transistors and organic light emitting diodes, especially through holes formed in the substrate, leading to reliability issues.
Innovation Solution
A method involving a substrate with a through-hole and a humidity preventing layer formed via sequential vapor infiltration (SVI) process, an organic/inorganic composite layer is used to reduce infiltration, combined with a circuit unit and encapsulating unit, and an opening unit is formed to penetrate these units, ensuring the humidity preventing layer is on the substrate's outskirt and inside, blocking infiltration paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a through-hole is formed in the substrate to enable flexibility and foldability, then the substrate can be bent and folded, but humidity and oxygen infiltration paths are created that damage the organic light emitting diodes
Solution Approach 1:
The encapsulation structure is segmented into multiple parts: a first encapsulation layer covering the bottom surface and side surfaces of the substrate, a second encapsulation layer covering the top surface, and a filling material within the through-hole. This segmentation allows each part to perform its specific function - the first layer blocks humidity from the bottom, the second layer seals the top, and the filling material prevents infiltration through the hole itself, collectively solving the reliability issue while maintaining flexibility
Solution Approach 2:
A filling material is introduced as an intermediary substance within the through-hole to block the direct infiltration path of humidity and oxygen. This filling material acts as a mediator between the flexible substrate structure and the protection requirement, allowing the through-hole to remain for flexibility while the filling material prevents harmful substance infiltration
2Reliability
If conventional encapsulation methods are used to protect against humidity, then protection is provided, but the substrate loses flexibility and cannot be bent or folded
Solution Approach 1:
The encapsulation structure applies different properties to different locations: the first encapsulation layer is applied to the bottom and side surfaces where flexibility is needed, while the second encapsulation layer is applied to the top surface where protection is prioritized. The filling material is locally placed within the through-hole. This local differentiation allows the substrate to maintain flexibility in critical areas while providing adequate protection
Solution Approach 2:
The encapsulation layers are designed as thin film structures that can bend and flex with the substrate. These thin film encapsulation layers provide protection against humidity and oxygen infiltration while maintaining the flexibility of the substrate, enabling the display apparatus to be bent and folded without compromising either protection or flexibility
3Reliability
If the humidity preventing layer is applied extensively on the substrate, then infiltration is blocked, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The encapsulation process is segmented into distinct steps: forming the first encapsulation layer on the bottom and side surfaces, forming the through-hole, filling the through-hole with protection material, and forming the second encapsulation layer on the top surface. This segmentation allows each step to be optimized independently and simplifies the overall manufacturing process compared to applying a single extensive encapsulation layer
Solution Approach 2:
The first encapsulation layer is formed preliminarily on the bottom and side surfaces before forming the through-hole and filling it. This preliminary action provides initial protection and establishes a foundation for subsequent steps, reducing the complexity of later processes by having already addressed part of the protection requirement
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 effectively reduces humidity and oxygen infiltration, enhancing the reliability of organic light emitting diodes by blocking infiltration paths and maintaining the flexibility of the substrate, allowing for the formation of an organic light emitting display apparatus that is bendable and foldable.
Implementation Method 1
the humidity preventing layer may be disposed on the substrate via a sequential vapor infiltration (SVI) process
Implementation Method 2
the humidity preventing layer may be disposed on the substrate via a sequential vapor infiltration (SVI) process, in which an inorganic precursor penetrates into the free volume
Data Source
AI summary
A method of manufacturing an organic light emitting display apparatus includes: preparing a substrate having a first surface and a second surface opposite to the first surface; forming a through-hole penetrating the substrate from the first surface to the second surface; forming a humidity preventing layer on the substrate; forming a plurality of organic light emitting diodes on the substrate; and removing an organic light emitting diode adjacent to the through-hole from among the plurality of organic light emitting diodes, in which the humidity preventing layer may be formed on the substrate via a sequential vapor infiltration (SVI) process.