Multi-Layer Insulating Structure for OLED Moisture Barrier
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Solution Overview
Problem
The existing organic light-emitting display devices using oxide semiconductors face challenges with moisture and oxygen penetration, affecting threshold voltage stability, and current methods for enhancing barrier characteristics, such as using aluminum oxide or titanium nitride layers, are difficult to apply to large substrates and have low mass productivity.
Innovation Solution
The implementation of a multi-layered insulating structure comprising a first silicon oxide layer, a second metal oxide layer with a gradient metal content, a third metal oxide or nitride layer, and an optional fourth silicon oxide layer, which are formed using PECVD or sputtering methods, to effectively prevent moisture and oxygen penetration and enhance barrier characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum oxide or titanium nitride layers are applied to strengthen barrier characteristics against moisture or oxygen, then the barrier characteristics are improved, but the ease of manufacture deteriorates because these layers require reactive sputtering or atomic layer deposition methods which are difficult to apply to large substrates and have low mass productivity
Solution Approach 1:
The insulating layer is divided into multiple sub-layers with different materials and functions: a first insulating layer (silicon oxide) providing basic insulation, a second insulating layer (metal oxide with gradient structure) providing intermediate barrier properties, and a third insulating layer (aluminum oxide or titanium nitride) providing strong barrier characteristics. This segmentation allows each layer to be optimized for its specific function while using manufacturing methods suitable for large substrates.
Solution Approach 2:
The patent uses a composite insulating layer structure combining different materials (silicon oxide, metal oxide with gradient composition, aluminum oxide, titanium nitride) to achieve superior barrier characteristics. The composite structure leverages the advantages of each material: silicon oxide for good insulation and ease of deposition, metal oxide gradient layer for intermediate barrier properties and stress management, and aluminum oxide/titanium nitride for strong moisture and oxygen barrier. This composite approach enables mass production on large substrates while maintaining high reliability.
2Device complexity
If a single-layer insulating structure is used, then the device complexity is reduced, but the reliability deteriorates due to insufficient barrier characteristics against moisture or oxygen penetration
Solution Approach 1:
The insulating layer is segmented into multiple sub-layers, each with specific thickness and composition optimized for its function. The first insulating layer provides basic electrical insulation, the second insulating layer with gradient metal content provides intermediate barrier properties and manages stress, and the third insulating layer provides strong barrier characteristics. This segmentation achieves superior reliability without excessive complexity by using a modular layered approach.
Solution Approach 2:
Different regions of the insulating layer have different properties optimized for their specific functions. The first insulating layer has properties optimized for electrical insulation, the second insulating layer has a gradient metal content distribution providing varying barrier properties through its thickness, and the third insulating layer has properties optimized for moisture and oxygen barrier. This local quality optimization ensures each part of the insulating structure performs its specific function effectively.
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 solution allows for the easy application of organic light-emitting display devices to large substrates and enables mass production while providing superior protection against moisture and oxygen, thereby stabilizing the threshold voltage and improving DC stability.
Implementation Method 1
formed using PECVD or sputtering methods
Implementation Method 2
formed using PECVD or sputtering methods
Implementation Method 3
a second insulating layer substantially formed from a metal oxide and formed on the first insulating layer... to effectively prevent moisture and oxygen penetration
Data Source
AI summary
An organic light-emitting display device, which may be configured to prevent moisture or oxygen from penetrating the organic light-emitting display device from the outside is disclosed. An organic light-emitting display device, which is easily applied to a large display device and/or may be easily mass produced is further disclosed. Additionally disclosed is a method of manufacturing an organic light-emitting display device. An organic light-emitting display device may include, for example, a thin-film transistor (TFT) including a gate electrode, an active layer insulated from the gate electrode, source and drain electrodes insulated from the gate electrode and contacting the active layer and an insulating layer disposed between the source and drain electrodes and the active layer; and an organic light-emitting diode electrically connected to the TFT. The insulating layer may include, for example, a first insulating layer contacting the active layer; and a second insulating layer formed of a metal oxide and disposed on the first insulating layer.