Dual-Panel OLED Display with Undercut Buffer Patterns
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Solution Overview
Problem
The existing organic electroluminescence display devices, particularly the top emission type, face limitations in light efficiency due to the materials used for the cathode and organic luminescent layer, which restricts high-resolution applications and increases manufacturing costs due to defects in the organic electroluminescent diode device during the forming process.
Innovation Solution
A dual-panel type organic electroluminescence display device is fabricated using a first substrate with an organic electroluminescence diode device and a second substrate with a thin film transistor, where a connection electrode electrically connects the two, and buffer patterns are used to create a cavity and undercut structure to separate pixel regions, improving light efficiency and reducing material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a top emission type organic electroluminescence display device is used to improve aperture ratio, then light emission through the encapsulation substrate is facilitated, but light efficiency is lowered due to material limitations of the cathode and organic luminescent layer
Solution Approach 1:
The device is divided into two separate substrates: the first substrate contains the organic electroluminescence diode device while the second substrate contains the thin film transistor. This segmentation allows independent optimization of each component, enabling the organic LED to be designed for high light efficiency while the TFT is optimized for driving functionality, thereby resolving the contradiction between aperture ratio and light efficiency.
Solution Approach 2:
A connection electrode serves as an intermediary component that electrically connects the thin film transistor on the second substrate to the organic electroluminescence diode device on the first substrate. This intermediary structure enables flexible wiring design that can accommodate high aperture ratios while maintaining efficient electrical connections for high light efficiency operation.
2Device complexity
If the array device and organic electroluminescent diode device are formed sequentially on the same substrate, then integration is achieved, but manufacturing cost increases and yield decreases when defects occur in the organic electroluminescent diode device
Solution Approach 1:
The array device and organic electroluminescence diode device are segmented onto different substrates (second substrate for TFT, first substrate for OLED). This allows them to be manufactured independently and then bonded together, so that defects in the organic electroluminescence diode device do not cause discarding of the entire array substrate, thereby improving manufacturing yield while maintaining integration through bonding.
Solution Approach 2:
The thin film transistor is formed on the second substrate in advance, and the organic electroluminescence diode device is formed on the first substrate separately. These preliminary actions on separate substrates allow independent optimization and defect isolation, enabling the final bonded structure to achieve integration benefits without the yield penalties of sequential formation on the same substrate.
3Reliability
If buffer patterns are used to separate adjacent pixel regions, then short circuits are prevented, but manufacturing precision is reduced due to etching variability
Solution Approach 1:
The buffer pattern structure is extended into the third dimension by forming an undercut structure where the first buffer pattern is etched deeper than the second buffer pattern. This vertical dimensionality change provides enhanced separation between adjacent pixel regions, improving short circuit prevention reliability while the multi-layer structure compensates for etching variability to maintain adequate dimensional control.
Solution Approach 2:
The first buffer pattern and second buffer pattern are arranged in a nested configuration where the first buffer pattern is etched to form an undercut structure beneath the second buffer pattern. This nested arrangement creates a robust separation structure that prevents short circuits between adjacent pixels while the hierarchical design provides tolerance against etching process variations.
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 enhances light efficiency, increases aperture ratio, and reduces manufacturing defects and costs by allowing independent processing of the thin film transistor and organic electroluminescent diode, while maintaining structural stability and preventing short circuits.
Implementation Method 1
An organic electroluminescence display device uses a light emission phenomenon occurring when an electron in an excited state is transferred to a ground state
Data Source
AI summary
The display device includes a first substrate, a second substrate, a spacer and a connection electrode. The first substrate includes an organic electroluminescence diode device, and the second substrate faces the first substrate and includes a thin film transistor. The connection electrode is configured to electrically connect the thin film transistor and the organic electroluminescence diode device. The display device further includes a first buffer pattern configured to separate two adjacent pixel regions and a second buffer pattern overlying the first buffer pattern and having a predetermined shape. The first buffer pattern is etchable to produce a cavity between the two adjacent pixel regions. The cavity can be enlarged to the extent that the shape of the second buffer pattern is maintained.