OLED Intermediate Layer Thickness Control for High-Definition Displays
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Solution Overview
Problem
Conventional organic light-emitting display devices face challenges in achieving efficient light emission due to difficulties in precisely patterning thin organic layers, leading to issues with driving voltage, current density, brightness, color purity, and luminous efficiency, especially as the distances between sub-pixels decrease, limiting the production of high-definition displays.
Innovation Solution
The solution involves forming an intermediate layer as one piece across adjacent sub-pixels, with varying thicknesses optimized for each color, allowing for improved patterning and alignment, and using masks with larger openings to simplify the manufacturing process, thereby enhancing the precision and efficiency of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If masks with smaller openings are used to form intermediate layers for high-definition displays, then the definition and resolution of the display improve, but the manufacturing precision and alignment difficulty worsen
Solution Approach 1:
The patent divides the intermediate layer formation into multiple sequential steps with different mask patterns. Instead of using a single fine-pitched mask for all sub-pixels, the process segments the deposition into multiple coarser mask applications, reducing alignment difficulty while achieving fine final patterns through cumulative layering.
Solution Approach 2:
The patent introduces a temporal dimension to the pattern formation process by depositing intermediate layers in multiple sequential steps rather than attempting to create the final pattern in a single step. This multi-stage approach allows each mask to be coarser, while the combination of multiple deposition layers achieves the required fine pitch.
2Reliability
If the thickness of intermediate layers is precisely controlled for each sub-pixel, then the luminous efficiency and color purity improve, but the manufacturing complexity increases
Solution Approach 1:
The patent applies different thicknesses of intermediate layers to different sub-pixel regions (red, green, blue) based on their specific requirements. By forming intermediate layers with varying local thicknesses through multiple mask-aligned deposition steps, each sub-pixel receives the optimal intermediate layer thickness for its color characteristics, improving luminous efficiency while managing complexity through systematic patterning.
3Manufacturing precision
If multiple masks with fine pitch are used for depositing emission and intermediate layers, then the sub-pixel patterning precision improves, but the production yield decreases due to alignment errors
Solution Approach 1:
The patent segments the intermediate layer deposition into multiple steps, each using a mask that is coarser than the final required pitch. This segmentation reduces the alignment precision requirement for each individual mask while achieving the fine final pattern through the cumulative effect of multiple deposition layers, thereby improving production yield.
Solution Approach 2:
The patent performs preliminary deposition of intermediate layers using coarser masks before final emission layer patterning. This preliminary action with less stringent alignment requirements creates a foundation that facilitates the subsequent fine-pitch emission layer deposition, improving overall yield by reducing cumulative alignment errors.
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 enables better control over the thickness of intermediate layers, improving driving voltage, current density, brightness, color purity, and luminous efficiency, while simplifying the manufacturing process and reducing costs by allowing for the production of high-definition displays with increased yield.
Implementation Method 1
An organic light-emitting display device according to the deposition method includes a first electrode and a second electrode; an intermediate layer between the first electrode and the second electrode; and an emission layer between the first electrode and the second electrode
Data Source
Figure 1A
Figure 1B
Figure 2~3A
AI summary
An organic light-emitting display device and a method of manufacturing the same, the organic light-emitting display device including pixels (R,G,B) including opposing first (131) and second electrodes (134), and an intermediate layer (142) disposed between the first (131) and second electrodes (134). The pixels are divided into red, green, and blue sub-pixels. The intermediate layer (142) has a thickness that varies according to the sub-pixels (R,G,B).