Recessed Charge Transport Layer for High-Definition OLED Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing cost of organic EL elements increases due to the complexity of creating a two-layered bank structure, which is necessary for high-definition patterning of light-emitting layers.
Innovation Solution
A recessed structure in the charge injection transport layer, composed of a metal compound with higher liquid-philicity than the bank surface, allows ink to accumulate and stay within defined regions, eliminating the need for a two-layered bank and reducing manufacturing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two-layered bank structure is used to achieve high-definition patterning, then the light-emitting layer can be patterned with high precision, but the manufacturing cost increases due to the complexity of the structure and number of processes
Solution Approach 1:
The charge injection transport layer is designed with spatially varying properties: it has a recessed portion in the region defined by the bank (lower than the bottom surface of the bank) and a flat portion in other regions. This local structural differentiation enables the recessed portion to accumulate and hold ink drops within the bank region, preventing overflow into adjacent pixel regions, thereby achieving high-definition patterning without requiring a complex two-layered bank structure
Solution Approach 2:
The charge injection transport layer, particularly its recessed portion, serves as an intermediary structure between the bank and the ink drops. The recessed portion acts as a containment structure that physically holds the ink drops, while the liquid-philic surface of the charge injection transport layer enhances ink adhesion. This intermediary mechanism prevents ink overflow without requiring the complex two-layered bank configuration
2Manufacturing precision
If a two-layered bank structure is used to prevent ink overflow, then high-definition patterning is achieved, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The invention merges the functions of the bank and the charge injection transport layer to achieve ink containment. Instead of using a separate two-layered bank structure, the charge injection transport layer is integrated with the bank region, where its recessed portion and liquid-philic surface work together to hold ink drops. This integration simplifies the manufacturing process by eliminating the need for separate bank layer construction while maintaining high-definition patterning capability
Solution Approach 2:
The charge injection transport layer provides self-containing functionality for ink drops through its recessed structure and liquid-philic surface properties. The recessed portion automatically accumulates and holds the ink drops within the bank region, and the liquid-philic surface ensures strong adhesion without requiring additional liquid-repellent treatments on the bank. This self-service mechanism simplifies manufacturing by eliminating complex multi-layer bank construction and multiple surface treatment processes
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 enables high-definition patterning of light-emitting layers while simplifying the manufacturing process and reducing costs, as the recessed portion effectively holds ink without overflowing, preventing irregular luminance and short circuits.
Implementation Method 1
the charge injection transport layer is principally composed of a metal compound that is more liquid-philic than a surface of the bank and has high wettability to the ink
Implementation Method 2
the inner surface of the recessed portion can stably hold the drops of the ink therein
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Provided is a light emitter in which high-definition light-emitting layer is patterned, and which can be manufactured at low cost. To achieve the aim, the light emitter including a first electrode 2, a charge injection transport layer 4, a light-emitting layer 6, and a second electrode 8 that are layered in this order, and at least the light-emitting layer 6 is defined by a bank 5. the bank 5 is liquid-repellent at least on a surface thereof, and the charge injection transport layer 4 is principally composed of a metal compound that is more liquid-philic than the surface of the bank. Also, the charge injection transport layer 4 has a recessed structure so that in a region defined by the bank 5, the charge injection transport layer 4 is lower than a bottom surface 5a of the bank 5.