OLED Micro-Cavity Layer Structure for High-Resolution Maskless Patterning
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Solution Overview
Problem
The existing organic light emitting display devices face challenges in achieving high-resolution patterns due to limitations in mask manufacturing technology, particularly when scaling up, as masks sag under weight and organic material spread increases, making it difficult to maintain desired patterns and achieve high resolution.
Innovation Solution
The solution involves an organic light emitting display device structure with multiple hole transporting layers and emission common layers of varying thicknesses between electrodes, allowing for micro-cavity effects that enhance light efficiency and color characteristics, while simplifying the manufacturing process by reducing the need for a fine metal mask (FMM) in multiple chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fine metal mask (FMM) process is used for patterning the emitting material layer, then manufacturing is enabled, but mask sags due to weight in large area applications making it difficult to form desired patterns
Solution Approach 1:
The emitting material layer is divided into multiple sub-layers (first emitting material layer and second emitting material layer) with different materials and functions. The first layer provides structural foundation while the second layer provides emission function, allowing each layer to be optimized independently for both manufacturability and precision.
Solution Approach 2:
Different regions of the emitting material layer have different properties - the first emitting material layer uses materials with specific characteristics for structural stability, while the second emitting material layer uses materials optimized for light emission. This local differentiation allows the structure to maintain precision without mask sagging.
2Area of stationary object
If the distance between the mask and deposition portion is increased, then large area coverage is achieved, but organic material spread increases reducing resolution
Solution Approach 1:
The emitting material layer is segmented into multiple functional sub-layers deposited in sequence. This allows the deposition process to be performed in multiple steps with smaller effective distances for each step, maintaining resolution while covering large areas through sequential layering rather than single-step wide-area deposition.
3Manufacturing precision
If multiple FMM processes are used in multiple chambers, then high-resolution patterning is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
Multiple patterning functions are merged into a single integrated emitting material layer structure with first and second emitting material layers. This consolidation allows the structure to achieve high-resolution patterning equivalent to multiple FMM processes while simplifying the manufacturing process to require fewer chambers and steps.
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 approach maintains excellent light output efficiency and color characteristics, simplifies the manufacturing process, and reduces costs by allowing for high-resolution displays without the limitations of traditional FMM processes.
Implementation Method 1
when an exciton in which the injected electron and hole are combined is shifted from an excited state to a base state, light is emitted
Implementation Method 2
distances between the first and second electrodes are differently formed by adjusting the respective thicknesses of the second to fourth hole transporting layers and the first to third emission common layers, thereby excellent light output efficiency is obtained
Data Source
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AI summary
Disclosed is an organic light emitting display device. The organic light emitting display device includes a substrate in which red, green, and blue pixel areas are defined, a first electrode (110) and a first hole transporting layer (130) that are formed on the substrate, first to third emission common layers (142, 144, 146) formed in each of the pixel areas on the first hole transporting layer (130), and an electron transporting layer (150) and a second electrode (160) that are formed on the third emission common layer (146). Accordingly, color mixture is prevented, limitations due to a defective mask are overcome, a process is simplified, and the manufacturing cost is saved.