OLED Sub-Electrode Layout for Oxygen-Resistant Pixel Reliability
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Solution Overview
Problem
Organic light-emitting display devices are susceptible to degradation due to oxygen penetration through fine pinholes or seams, leading to cathode oxidation and dead pixels, which degrades display quality.
Innovation Solution
Incorporating a sub-electrode layer with oxygen vacancies in the non-display area to suppress oxygen penetration, made of the same material and process as the anode, and using banks to expose parts of the sub-electrode layer, delaying oxygen introduction into the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the non-display area is reduced to make the display device slimmer, then the device thickness and bezel area are decreased, but oxygen penetration into the display area increases causing pixel degradation
Solution Approach 1:
The patent applies preliminary action by forming a sub-electrode layer in the non-display area before the cathode layer, and creating oxygen vacancies in this layer in advance. This pre-established oxygen barrier structure proactively prevents oxygen penetration before it can reach and oxidize the cathode, allowing the device to be made slimmer without compromising pixel reliability.
Solution Approach 2:
The sub-electrode layer with oxygen vacancies acts as an intermediary barrier between the external environment and the cathode. This intermediate layer specifically targets and adsorbs oxygen molecules, preventing them from reaching the cathode through pinholes or seams, thus resolving the contradiction between reduced bezel area and maintained pixel reliability.
2Reliability
If a sub-electrode layer with oxygen vacancies is added to suppress oxygen penetration, then pixel reliability is improved, but the number of process steps and manufacturing complexity increases
Solution Approach 1:
The patent merges the sub-electrode layer formation with the existing electrode manufacturing process. The sub-electrode layer is formed using the same material deposition process as the anode, and the oxygen vacancies are created during the same plasma treatment step used for cathode preparation. This consolidation avoids adding separate process steps while achieving oxygen barrier functionality.
Solution Approach 2:
The sub-electrode layer serves multiple functions: it acts as an oxygen barrier, provides electrical connectivity, and maintains structural integrity. By making this layer multi-functional, the patent achieves pixel protection without requiring additional specialized process steps, thus improving reliability without increasing manufacturing complexity.
3Illumination intensity
If the cathode is protected from oxygen oxidation, then display quality is maintained, but additional protective layers or structures are required increasing device complexity
Solution Approach 1:
The patent applies local quality by creating oxygen vacancies specifically in the region where the sub-electrode layer overlaps with the bank opening portions in the non-display area. This localized treatment provides oxygen barrier functionality exactly where needed (at the boundaries where oxygen penetration occurs) without requiring additional protective layers across the entire device, thus maintaining display quality without increasing overall structural complexity.
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
Minimizes pixel degradation by oxygen without significantly increasing process steps or costs, enhancing display reliability by preventing cathode oxidation.
Implementation Method 1
The sub-electrode layer includes oxygen vacancies in an area in which the sub-electrode layer overlaps the plurality of bank opening portions
Data Source
AI summary
A display device includes a sub-electrode layer disposed on the substrate while corresponding to at least a part of the non-display area; and banks disposed on the planarization layer in the display area so as to expose at least a part of the anode and disposed on the sub-electrode layer in the non-display area, in which the bank includes a plurality of bank opening portions disposed in the non-display area so as to expose at least a part of the sub-electrode layer, and in which the sub-electrode layer includes oxygen vacancies in an area in which the sub-electrode layer overlaps the plurality of bank opening portions. Therefore, the display device according to the present disclosure, it is possible to provide the display device capable of implementing excellent reliability by suppressing degradation of the pixel caused by oxygen.