OLED Encapsulation Layer Edge Alignment via Strippable Mask
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Solution Overview
Problem
The existing Thin Film Encapsulation (TFE) technology for OLEDs faces challenges in forming organic material layers, leading to defects such as slope climbing, uneven layer thickness, and poor linearity due to viscosity and surface tension issues, affecting the encapsulation effect and luminescence of the light emitting layer.
Innovation Solution
A method involving the formation of a strippable layer on a substrate, followed by an organic material layer that covers both regions, with the strippable layer being stripped to create an organic encapsulation layer, using techniques like photoresist coating and ink-jet printing, and incorporating inorganic material layers to control surface roughness and overflow, ensuring edge alignment and defect removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid organic material is coated on the light emitting layer to form the organic material layer, then the encapsulation structure is formed, but defects such as slope climbing, uneven layer thickness, and poor linearity occur due to viscosity and surface tension issues
Solution Approach 1:
A strippable layer is introduced as an intermediary between the substrate and the organic material layer. This layer acts as a mediator to control the spreading and curing of the organic material, preventing edge defects such as slope climbing and poor linearity while maintaining good encapsulation effect.
Solution Approach 2:
The strippable layer is formed in advance before coating the liquid organic material. This preliminary action prepares the surface with controlled properties that guide the organic material flow and curing process, preventing defects before they occur.
2Reliability
If the organic material layer is formed to cover the display region, then encapsulation is achieved, but the overflow portion causes poor edge alignment and wide borders
Solution Approach 1:
The strippable layer serves as a temporary boundary structure that confines the organic material during coating and curing. After the organic material layer is formed, the strippable layer is removed, taking with it any overflow material and leaving precise edge alignment with narrow borders.
Solution Approach 2:
The strippable layer is a temporary structure that is intentionally discarded after serving its purpose. It is removed after the organic material layer is formed, taking unwanted overflow material with it, thus achieving narrow borders without compromising the encapsulation quality.
3Manufacturing precision
If photoresist is coated and then stripped to remove overflow portion, then edge alignment is improved, but additional process steps are required
Solution Approach 1:
The formation of the organic material layer and the removal of overflow are merged into a single integrated process. The strippable layer is formed, the organic material is coated and cured, and then the strippable layer with overflow is removed in one sequence, simplifying the overall process while achieving good edge alignment.
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 method improves the edge characteristics and encapsulation effect of the organic film layer, promoting a narrow border and enhancing the display performance by aligning the organic encapsulation layer edges with the display region, thus addressing the defects in the TFE technology.
Implementation Method 1
illuminating or heating the photoresist so as to lower the viscidity of the photoresist
Data Source
AI summary
The disclosure provides a method of manufacturing an encapsulation layer and a display substrate. The method of manufacturing the encapsulation layer includes: forming a strippable layer on a first region of a substrate; forming an organic material layer on a second region of the substrate, the organic material layer comprising a portion covering the second region and an overflow portion exceeding the second region and at least partially covering the first region, wherein the first region and the second region are adjoined to each other; and stripping the strippable layer from the substrate to remove the overflow portion of the organic material layer and form an organic encapsulation layer.