OLED First Electrode Flatness via Buffer Film Via Hole
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Solution Overview
Problem
Existing organic light emitting display apparatuses face challenges in maintaining surface flatness of electrodes, which can lead to electrical failures and degraded image quality due to protrusions formed during the crystallization process, and struggle with efficient light emission directionality.
Innovation Solution
The organic light emitting display apparatus includes a substrate with a buffer film having a via hole, a thin film transistor, and electrodes, where the first electrode corresponds to the via hole, ensuring the gate insulating film is between the electrode and the substrate, and the intermediate layer includes an organic emission layer to emit visible light without overlapping with the TFT, enhancing light reflectivity and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active layer undergoes crystallization process to improve electrical properties, then electrical conductivity is improved, but protrusions are formed on the electrode surface causing surface flatness degradation
Solution Approach 1:
A buffer film is introduced as an intermediary layer between the substrate and the active layer. This buffer film absorbs or mitigates the harmful effect of protrusion formation during crystallization, preventing direct transmission of surface irregularities to the electrode while allowing the crystallization process to proceed for improved electrical conductivity.
Solution Approach 2:
The structure is segmented into distinct functional layers: substrate, buffer film, active layer, and electrode. This segmentation isolates the crystallization process effects to specific regions, allowing the buffer film to handle surface irregularities while the electrode maintains its functional integrity and flatness.
2Area of stationary object
If the intermediate layer is positioned to overlap with the TFT for compact design, then device area is reduced, but light emission is interfered with causing degraded image quality
Solution Approach 1:
The intermediate layer is repositioned from a vertical overlap configuration to a lateral adjacency configuration. Instead of stacking the intermediate layer directly over the TFT (vertical dimension), it is positioned beside the TFT (lateral dimension), eliminating light emission interference while maintaining compact overall device design through efficient space utilization in the planar layout.
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 configuration improves the image quality by preventing surface degradation of the first electrode, increasing luminous efficiency, and ensuring uniform light emission without interference from the TFT, thus enhancing the overall performance of the display apparatus.
Implementation Method 1
When a voltage is applied to the first and second electrodes, visible light is emitted from the organic emission layer
Data Source
AI summary
The organic light emitting display apparatus includes a substrate; a buffer film on the substrate, the buffer film including a via hole, a thin film transistor (TFT) on the buffer film, the TFT including an active layer, a gate electrode, a source electrode, and a drain electrode, a first electrode electrically connected to one of the source electrode and the drain electrode and corresponding to the via hole; an intermediate layer on the first electrode, the intermediate layer including an organic emission layer, and a second electrode on the intermediate layer.