Pixel Define Layer Preparation for OLED Adhesion and Moisture Control
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Solution Overview
Problem
Organic light emitting display devices face issues with peeling of the common layer (HTL) due to low surface roughness of colored patterns, leading to pixel defects and reduced lifespan, and high moisture content causing pixel shrinkage and dark spots.
Innovation Solution
A method for preparing a pixel defining layer using a photosensitive resin composition with post-heat treatment at 210° C. to 300° C. for 30 to 120 minutes, achieving a surface roughness of 1.48 nm to 3.0 nm and moisture content of 50 ppm or less, incorporating a colorant with inorganic or organic pigments, and using a cardo-based binder resin to enhance adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface roughness of colored patterns is low, then the adhesion to HTL material is low, but this causes peeling during deposition or after panel formation
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness of colored patterns to fall within a specific range (Ra 0.5 nm to 3.0 nm) through optimized post-heat treatment conditions (temperature, time, atmosphere). This parameter optimization ensures sufficient adhesion between the colored patterns and HTL material while maintaining manufacturing precision, thereby preventing peeling during deposition or after panel formation.
2Reliability
If sufficient crosslinking is not achieved during post-heat treatment, then moisture is absorbed from external environment, but this causes pixel shrinkage, dark spots, and electrode oxidation
Solution Approach 1:
The patent applies preliminary action by performing post-heat treatment at optimized temperature and time conditions before the device is put into service. This preliminary crosslinking process removes moisture and establishes a moisture barrier in advance, preventing subsequent moisture absorption from the external environment that would cause pixel shrinkage, dark spots, and electrode oxidation.
Solution Approach 2:
The patent uses parameter changes by conducting post-heat treatment at specific temperature ranges and durations to achieve sufficient crosslinking of the colored patterns. These parameter optimizations ensure that the patterns develop adequate crosslinking density to act as an effective moisture barrier, preventing harmful moisture absorption while maintaining device reliability.
3Quantity of substance
If post-heat treatment is performed at high temperature for long duration, then moisture content is reduced, but this increases processing time and energy consumption
Solution Approach 1:
The patent applies parameter changes by optimizing the post-heat treatment conditions to specific temperature ranges and time durations that achieve the desired moisture content reduction without excessive processing time. These optimized parameters balance moisture removal effectiveness with processing efficiency, reducing moisture to acceptable levels while minimizing energy consumption and production time.
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 method ensures reliable adhesion of the common layer, reduces pixel defects, and minimizes moisture-related issues, thereby increasing the lifespan and luminance of organic light emitting display devices.
Implementation Method 1
applying and coating a photosensitive resin composition; performing prebaking; performing exposure; performing development; and performing post-heat treatment
Implementation Method 2
performing post-heat treatment, wherein it is preferable that the post-heat treatment step is performed at an oven temperature of 210° C. to 300° C. for 30 to 120 minutes, and a coating film after the post-heat treatment step has a moisture content of 50 ppm or less
Data Source
AI summary
Provided is a method for not only reducing peeling in a post-process of a common layer (HTL) but also increasing display reliability and lifespan by implementing a colored pattern having a constant roughness value on an electrode substrate, wherein the method is also for ensuring vivid colors and increasing display reliability and lifespan by implementing a colored pattern having a low moisture content on an electrode substrate, thereby minimizing the generation of moisture in the panel state.