Island-Electrode Display Layout With Hybrid Emission Layer Patterning
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Solution Overview
Problem
Existing display devices with light-emitting layers formed by inkjet printing face issues of reduced light-emitting regions due to large bank partition walls covering a significant area of the electrodes, leading to decreased efficiency and luminance.
Innovation Solution
A display device design that includes a substrate with first electrodes shaped into islands, a first light-emitting layer formed by photolithography, a second light-emitting layer formed by inkjet printing, and a picture frame-shaped bank to increase light-emitting regions, with the second layer in contact with the inner side of the bank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all light-emitting layers are formed by inkjet printing with tall bank partition walls, then light-emitting layers can be formed efficiently, but the banks cover large area of electrodes and reduce light-emitting regions
Solution Approach 1:
The patent divides the light-emitting layer formation process into two segments: photolithography for first light-emitting layers and inkjet printing for second light-emitting layers. This segmentation allows each method to be applied where it provides the greatest benefit, with photolithography enabling precise pattern formation without requiring tall banks, thus reducing bank area coverage while maintaining formation efficiency.
Solution Approach 2:
The patent applies different formation methods to different light-emitting layers based on their specific requirements. First light-emitting layers use photolithography for precise patterning, while second light-emitting layers use inkjet printing for efficient deposition. This local differentiation optimizes both formation efficiency and light-emitting region area for each layer type.
2Manufacturing precision
If bank partition walls are made taller to define light-emitting regions, then light-emitting layer boundaries are clearer, but the banks cover more electrode area and reduce light-emitting regions
Solution Approach 1:
The patent replaces the mechanical bank partition wall system with a photolithography-based pattern definition system for first light-emitting layers. This substitution eliminates the need for tall physical banks to define boundaries, achieving precise light-emitting region boundaries through photolithographic masks instead, thereby reducing bank area coverage while maintaining manufacturing precision.
3Manufacturing precision
If all light-emitting layers are formed by vapor deposition, then light-emitting layers can be formed with good uniformity, but the forming step requires time and costs more
Solution Approach 1:
The patent changes the formation method parameter from uniform vapor deposition to a hybrid approach using photolithography and inkjet printing. This parameter change allows different light-emitting layers to be formed by the most suitable method: photolithography for precise patterning and inkjet printing for efficient deposition, thereby improving overall formation efficiency while maintaining uniformity where needed.
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 design enhances light-emitting regions, reduces electrode coverage, and improves luminance while maintaining efficient formation of light-emitting layers, minimizing damage during manufacturing processes.
Implementation Method 1
a first light-emitting layer formed by photolithography
Implementation Method 2
a second light-emitting layer formed by inkjet printing
Data Source
AI summary
A display device includes: a plurality of first electrodes shaped into islands; a first light-emitting layer formed to overlap with a first electrode among the plurality of the first electrodes, the first light-emitting layer containing a first light-emitting material and resin; a second light-emitting layers formed to overlap with another first electrode among the plurality of the first electrodes, the second light-emitting layers being made of a second light-emitting material; and a bank formed in a shape of a picture frame, or formed to include two partition walls facing each other and separating an inner region from an outer region. The second light-emitting layer is provided behind the bank to be in contact with an inner side face of the bank, and the first light-emitting layer is formed out of the bank.