OLED Passivation Protrusion Reflects Light to Enlarge Emission Area
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Solution Overview
Problem
The existing manufacturing technologies for organic light-emitting display apparatus face limitations in achieving high-resolution displays due to the shadow effect of fine metal masks, leading to defects and restricted emission areas.
Innovation Solution
The proposed solution involves an organic light-emitting display apparatus with a substrate, pixel electrode, pixel-defining film, intermediate layer with an emission layer, counter electrode, passivation layer having a cover portion and protrusion, and an encapsulation member. The passivation layer is formed using a vapor deposition method with good step coverage to cover the counter electrode, and the protrusion acts as a reflective plate to enlarge the emission area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine metal mask (FMM) is used to deposit the organic emission layer, then the organic emission layer can be deposited on the substrate, but the shadow effect of the FMM causes defects and limits the emission area
Solution Approach 1:
The invention removes the fine metal mask (FMM) from the deposition process entirely, replacing it with a maskless vapor deposition method. This extraction of the problematic FMM eliminates the shadow effect that limited the emission area while maintaining the ability to deposit the organic emission layer with sufficient precision through controlled deposition parameters and substrate positioning.
Solution Approach 2:
The invention replaces the mechanical FMM system with a vapor deposition system that uses controlled material evaporation and condensation. By substituting the mechanical mask-based approach with a vapor-phase deposition process, the shadow effect is eliminated while the organic emission layer is still deposited accurately on the substrate through controlled vapor transport and condensation.
2Area of stationary object
If the emission area is enlarged, then the display performance is improved, but defects occur due to the shadow effect of the FMM
Solution Approach 1:
By removing the FMM from the system, the invention eliminates the shadow effect that caused defects when attempting to enlarge the emission area. The maskless vapor deposition approach allows uniform material distribution across larger areas without the geometric shadows that plagued FMM-based methods, thereby improving both emission area and display quality simultaneously.
Solution Approach 2:
The invention introduces vapor-phase organic material as an intermediary medium that can be deposited uniformly across the substrate without the shadow constraints of solid masks. The vapor phase allows material to reach all areas of the substrate evenly, serving as a mediator that enables large-area deposition while maintaining high reliability and eliminating shadow-effect defects.
3Reliability
If a passivation layer is formed to cover the counter electrode, then the OLED is protected, but the emission area is reduced due to the cover portion
Solution Approach 1:
The invention extends the passivation layer in the vertical dimension by adding protrusions that rise from the substrate surface. These three-dimensional protrusions provide protection along the side walls of the counter electrode, allowing the cover portion to be minimized in horizontal area while maintaining comprehensive protection. This dimensional transition enables both protection and maximized emission area.
Solution Approach 2:
The passivation layer is segmented into multiple functional regions: a cover portion that protects the top surface of the counter electrode and protrusions that protect the side walls. This segmentation allows each region to perform its specific protective function efficiently, minimizing the horizontal footprint of the cover portion while ensuring complete protection through the added vertical protrusion elements.
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 reduces defects in the OLED and enlarges the emission area by effectively using the passivation layer's protrusion as a reflective plate, enhancing the display's performance and manufacturing efficiency.
Implementation Method 1
The passivation layer is formed using a vapor deposition method with good step coverage to cover the counter electrode
Implementation Method 2
the protrusion acts as a reflective plate to enlarge the emission area
Data Source
AI summary
An organic light-emitting display apparatus including: a substrate; a pixel electrode located on the substrate; a pixel-defining film covering an end portion of the pixel electrode; an intermediate layer located on the pixel electrode and including an emission layer; a counter electrode located on the intermediate layer; a passivation layer located on the counter electrode and including a cover portion covering a top surface of the counter electrode and a protrusion extending from an end portion of the cover portion away from the substrate; and an encapsulation member covering the passivation layer.