OLED Pixel Defining Layer Outgassing Hole Design
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Solution Overview
Problem
Organic light-emitting displays face defects due to outgassing trapped in the planarization film during the baking process, which deforms the pixel defining layer and electrodes, leading to manufacturing defects.
Innovation Solution
Incorporating an outgassing hole in the pixel defining layer to release trapped outgassing from the planarization film, optionally covered by an organic passivation film to prevent damage and ensure smooth nozzle printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the planarization film is made of organic material to achieve smooth surface and good adhesion, then the planarization quality is improved, but outgassing is generated during baking process causing deformation and defects
Solution Approach 1:
The patent extracts the harmful outgassing from the planarization film by forming through-holes that extend from the upper surface to the lower surface of the planarization film. These through-holes allow trapped gases to escape during the baking process, preventing deformation and defects while maintaining the organic material composition of the planarization film for smooth surface and good adhesion.
2Stability of the object's composition
If the pixel defining layer is made of inorganic material to provide structural stability, then the structural integrity is improved, but outgassing from the planarization film underneath cannot be released causing internal pressure and deformation
Solution Approach 1:
The patent extracts the harmful trapped outgassing by forming through-holes that penetrate the pixel defining layer and extend into the planarization film. This allows gases generated during baking to escape through the through-holes, preventing internal pressure buildup and deformation of the structurally stable inorganic pixel defining layer.
Solution Approach 2:
The patent applies local quality by creating through-holes only in specific regions of the pixel defining layer where outgassing needs to escape, while maintaining the intact inorganic material structure in other regions. This localized modification allows gas release without compromising the overall structural integrity and stability of the inorganic pixel defining layer.
3Manufacturing precision
If multiple baking processes are performed to ensure complete organic light-emitting layer formation, then the layer quality is improved, but outgassing accumulation increases causing more severe deformation and defects
Solution Approach 1:
The patent extracts accumulated outgassing during multiple baking processes by providing through-holes in the planarization film and pixel defining layer. These through-holes enable continuous escape paths for gases generated during each baking step, preventing accumulation and the associated deformation and defects while allowing multiple baking cycles for high-quality organic light-emitting layer formation.
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 minimizes deformation and defects by allowing outgassing release, maintaining the integrity of the planarization film and electrodes, and ensuring a low defect rate in organic light-emitting display manufacturing.
Implementation Method 1
During the baking process, outgassing may be generated in the planarization film that is made of an organic material. However, since the pixel defining layer made of an inorganic material is disposed on the planarization film, the outgassing cannot be released from the planarization film.
Data Source
AI summary
The organic light-emitting display device includes: a substrate including a transistor region; and a thin-film transistor formed over the transistor region of the substrate and having a planarization film which is disposed over a source/drain electrode and a pixel defining layer which includes an aperture exposing a portion of a first electrode electrically connected to the source/drain electrode and defining a pixel region, wherein an outgassing hole is formed in a region of the pixel defining layer other than the aperture to expose the planarization film.