Pixel Define Layer Using Ultrafine Pigments
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Solution Overview
Problem
Organic light emitting display devices face issues with antireflection, moisture retention, and reduced luminance due to the use of large inorganic pigments in colored patterns, leading to pixel shrinkage and electrode oxidation, which affect display reliability and lifespan.
Innovation Solution
A method involving a photosensitive resin composition with inorganic pigments of 100 nm or less, applied through steps of prebaking, exposure, development, and post-heat treatment at 210-300°C, to achieve high optical density and low roughness, minimizing moisture content to 50 ppm or less, thereby reducing pattern residue and moisture absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If large inorganic pigments are used in colored patterns, then color visibility is improved, but pattern roughness increases and optical density decreases
Solution Approach 1:
The patent changes the particle size parameter of inorganic pigments from conventional large sizes to ultra-fine sizes of 100 nm or less. This parameter change simultaneously improves pattern smoothness and maintains high optical density, while the color visibility is preserved through proper selection of pigment material and composition ratios
2Illumination intensity
If large inorganic pigments are used in colored patterns, then color visibility is improved, but optical density decreases
Solution Approach 1:
The patent changes the particle size parameter to ultra-fine 100 nm or less, which increases the surface area to volume ratio. This allows for better light absorption efficiency per unit mass, achieving high optical density (OD 0.8/μm to 2.0/μm) while maintaining vivid color appearance
3Loss of time
If sufficient crosslinking is not achieved during post-heat treatment, then processing time is reduced, but moisture absorption increases
Solution Approach 1:
The patent performs prebaking before the main exposure and development process to remove moisture and volatile components in advance. This preliminary action reduces the moisture content of the coating film, so that even with moderate post-heat treatment conditions, the final moisture content remains at 50 ppm or less, preventing pixel shrinkage and electrode oxidation
Solution Approach 2:
The patent optimizes the post-heat treatment parameters including temperature (210-300°C) and time (30-120 minutes) to achieve sufficient crosslinking of the photosensitive resin. This controlled parameter change ensures complete crosslinking for moisture resistance while managing processing time efficiently
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 vivid colors, increased display reliability, and extended lifespan by achieving high optical density and low roughness while minimizing moisture content, thus preventing pixel shrinkage and electrode oxidation.
Implementation Method 1
colored patterns lack crosslinking during the development process
Implementation Method 2
the moisture is removed through the post-heat treatment process
Data Source
AI summary
Provided is a method for ensuring vivid colors and increasing display reliability and lifespan by implementing a colored pattern with high optical density on an electrode substrate, where the method uses a pigment dispersion in which a pigment having a size of 100 nm or less is used in order to increase the optical density and reduce roughness after completing the post-heat treatment process by including a colorant according to the present disclosure, and the method can minimize the reduction in the lifespan due to moisture in the panel state by minimizing the moisture content after completing the post-heat treatment process.