OLED Pixel-Defining Layer Stepped Portion Gas Escape
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Solution Overview
Problem
Gases are often entrapped between the organic layer and underlying layers during the fabrication of organic light emitting diodes, leading to unsatisfactory adhesion and performance issues.
Innovation Solution
Incorporating a stepped portion in the pixel-defining layer adjacent to the opening for the organic layer, which allows for the escape of gases during laser-induced thermal transfer, thereby improving adhesion between the organic layer and underlying layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser-induced thermal transfer is used to form the organic layer, then high-resolution patterns and uniform film thickness are achieved, but gases are entrapped between the organic layer and underlying layers causing poor adhesion
Solution Approach 1:
The pixel-defining layer is segmented to include a stepped portion with different height levels. This segmentation creates a physical pathway that divides the interface between the organic layer and underlying layers, allowing gas to escape during the laser-induced thermal transfer process while maintaining high-resolution patterning and uniform film thickness.
Solution Approach 2:
The stepped portion acts as an intermediary structure between the organic layer and the underlying electrode layer. During laser-induced thermal transfer, this intermediary feature provides a gas escape route, preventing gas entrapment and improving adhesion while preserving the benefits of high-resolution pattern formation and uniform film thickness achieved by the thermal transfer method.
2Device complexity
If conventional flat substrate structure is used, then fabrication is simple, but gases are trapped during organic layer formation leading to unsatisfactory adhesion
Solution Approach 1:
The substrate structure is segmented into different height levels through the stepped portion in the pixel-defining layer. This segmentation is achieved through simple photolithographic patterning and etching processes, maintaining relative fabrication simplicity while creating the necessary gas escape pathways to improve adhesion between the organic layer and underlying layers.
Solution Approach 2:
The substrate structure transitions from a two-dimensional flat surface to a three-dimensional stepped structure. This dimensional change creates vertical gas escape pathways without significantly complicating the fabrication process, as the stepped portion can be formed using standard photolithography and etching techniques applied to the pixel-defining layer.
3Quantity of substance
If deposition method with shadow mask is used, then organic layer is formed, but high-resolution patterning is difficult and large-area display fabrication is challenging
Solution Approach 1:
The stepped portion in the pixel-defining layer serves as an intermediary structure that works synergistically with the laser-induced thermal transfer method. This combination enables precise high-resolution patterning and uniform film thickness formation while the stepped feature prevents gas entrapment, making the process suitable for both high-resolution displays and large-area fabrication.
Solution Approach 2:
The conventional mechanical shadow mask deposition method is replaced with a laser-induced thermal transfer process. This substitution uses optical energy (laser) to transfer the organic layer from a donor substrate to the device substrate, achieving superior pattern resolution and uniformity. The stepped portion in the pixel-defining layer further enhances this process by preventing gas entrapment, enabling scalability to large-area displays.
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 effectively reduces gas entrapment, enhancing the adhesive strength and overall performance of the organic light emitting diodes by ensuring gases are discharged during the transfer process.
Implementation Method 1
laser-induced thermal transfer, wherein the organic material is provided on a donor substrate, the donor substrate is placed in close contact with the device substrate, and a laser is scanned across the donor substrate. Heat energy provided by the laser causes the organic material to transfer to the donor substrate, forming the organic layer.
Data Source
AI summary
An organic light emitting diode, and a method of fabricating the same, the organic light emitting diode including a pixel-defining layer disposed on a substrate, the pixel-defining layer having an opening therein and having at least one stepped portion formed adjacent to the opening, and an organic layer disposed in the opening and at least partially covering the at least one stepped portion.