Pixel Define Layer Preparation Using Sub-120nm Inorganic Pigments
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Solution Overview
Problem
Existing methods for preparing pixel defining layers in organic light-emitting display devices face challenges in achieving high optical density and low roughness while minimizing pattern residues, which affects visibility and reliability.
Innovation Solution
A method involving the application and coating of a photosensitive composition with inorganic pigments of average particle size 120 nm or less, followed by prebaking, exposure, development, and post-baking treatment, to achieve an optical density of 0.80/μm to 2.0/μm and a sintering hardness of 350 N/mm2 to 470 N/mm2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic pigment particle size is increased to enhance optical density, then optical density improves, but pattern residues increase and roughness increases causing decreased visibility and luminance reliability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of inorganic pigments to 120 nm or less, representing a significant reduction from conventional sizes. This parameter optimization enables the pigment particles to achieve high optical density while maintaining sufficient small size to prevent pattern residues and reduce surface roughness, thus resolving the contradiction between optical density and manufacturing precision
Solution Approach 2:
The patent uses composite materials by combining specifically sized inorganic pigments (120 nm or less) with organic pigments in a photosensitive composition. This composite approach allows the inorganic pigments to provide optical density while their controlled small size prevents the pattern residues and roughness issues that would occur with larger particles, simultaneously achieving both high reliability and manufacturing precision
2Strength
If organic pigment content is increased to enhance sintering hardness, then sintering hardness improves, but pattern residues are generated and dark spots appear
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size of inorganic pigments to 120 nm or less, which enables the system to achieve adequate sintering hardness through the inorganic pigment framework rather than relying on high organic pigment content. This parameter optimization prevents organic pigment-related defects such as pattern residues and dark spots while maintaining necessary mechanical strength
Solution Approach 2:
The patent uses composite materials by creating a synergistic combination of inorganic and organic pigments where the inorganic pigments (120 nm or less) provide the sintering hardness and structural integrity, while the reduced organic pigment content eliminates the generation of pattern residues and dark spots during processing
3Illumination intensity
If inorganic pigment particle size is increased to improve visibility, then optical density improves, but roughness increases causing decreased luminance reliability
Solution Approach 1:
The patent applies parameter changes by controlling inorganic pigment particle size to 120 nm or less, which optimizes the balance between visibility and luminance reliability. The small particle size ensures high optical density for excellent visibility while simultaneously maintaining surface smoothness and low roughness, thereby preserving luminance reliability without the trade-off that would occur with larger particles
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 effectively increases optical density near 550 nm, enhancing sintering hardness and modulus, while reducing pattern residues and surface roughness, thereby improving the visibility and reliability of the organic light-emitting display.
Implementation Method 1
a pixel defining layer formation unit configured to form a pixel defining layer on the lower substrate, the pixel defining layer including a pattern obtained through a photolithography process
Data Source
AI summary
Provided is a display having vivid colors, improved reliability, and lifespan by implementing a colored pattern having high optical density on an electrode substrate, wherein the optical density after completion of post-baking treatment process is increased using a colorant, a pigment dispersion having a size of 100 nm or less is used to reduce roughness, the pixel separation layer enables implementation of a flexible display and reduces the thickness and weight of the display, the visibility can be increased by blocking and absorbing external reflected light, and the hardness and modulus can be improved to the level of conventional pixel separation layers, thereby capable of implementing a display that does not generate cracks even when subjected to external impact, and a colored pattern with high optical density is realized on an electrode substrate, improving not only the vividness of the color but also impact resistance, reliability, and lifespan of the display.