Organic EL Layer Thickness Uniformity via Localized Heating
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Solution Overview
Problem
The manufacturing process of organic electroluminescent (EL) display devices using high molecular organic materials results in uneven thickness of the organic EL layer due to the phenomenon of liquid material being pressed up by the partitioning wall, leading to suboptimal light emission characteristics.
Innovation Solution
A manufacturing method involving a temperature distribution setting step, where specific regions adjacent to the partitioning wall are heated to a higher temperature than the rest of the pixel regions, ensuring uniform coating and drying of the organic material, thereby maintaining even film thickness across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the liquid material is coated on the pixel regions using conventional heating, then the coating process is simple, but the organic EL layer thickness becomes uneven due to liquid material being pressed up by the partitioning wall
Solution Approach 1:
The heating system applies different temperatures to different regions: a first temperature (higher) to regions adjacent to the partitioning wall and a second temperature (lower) to other pixel regions. This local quality differentiation prevents liquid material from being pressed up by the partitioning wall while maintaining uniform organic EL layer thickness across all pixel regions.
2Manufacturing precision
If uniform temperature heating is applied, then the heating process is simple, but the liquid material accumulates at the partitioning wall causing uneven film thickness
Solution Approach 1:
The heating system provides localized high temperature only to regions adjacent to the partitioning wall where liquid material accumulation occurs, while maintaining lower temperature in other regions. This targeted approach prevents film thickness unevenness while minimizing overall energy consumption compared to uniform high-temperature heating.
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 method achieves a uniform thickness of the organic EL layer, improving light emission consistency and reducing material loss, resulting in enhanced display quality and reliability.
Implementation Method 1
heating a first predetermined region adjacent to a part of a partitioning wall which is formed on one surface of a substrate and defines a plurality of surrounded-regions each of which is surrounded by the partitioning wall and includes a plurality of pixel-regions on which pixels are to be formed at a first temperature, and heating a second predetermined region other than the first predetermined region at a second temperature lower than the first temperature
Implementation Method 2
coating a liquid material, which is made of a high-molecular organic hole-transporting material dispersed or dissolved in a solvent, on the region and heating and drying the coated region, thereby to form the hole transporting layer
Data Source
AI summary
A partitioning wall is formed on one surface of a substrate. The partitioning wall has a lattice-like shape and defines a plurality of surrounded-regions. Each of the surrounded-regions is surrounded by the partitioning wall and includes a plurality of pixel-regions on which pixels are to be formed. A first predetermined region of the substrate adjacent to a part of the partitioning wall is maintained at a higher temperature, and a second predetermined region other than the first predetermined region is maintained at a lower temperature. Liquid which contains a carrier transporting material is coated on the pixel-regions in the surrounded-regions while maintaining the temperatures of the substrate.