Inorganic Bank Layer for OLED Ink Repellency
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Solution Overview
Problem
In organic light-emitting devices, the formation of organic functional layers is often defective due to ink repellency from second banks made of organic fluorine compounds, leading to uneven light emission across sub-pixels.
Innovation Solution
Incorporating an inorganic bank layer, such as silicon nitride or silicon oxide, on top of the organic bank layer in the first banks reduces the affinity between the organic fluorine compound of the second banks and the inorganic material, allowing ink to spread evenly and preventing defective formation of the organic functional layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If second banks are made of organic fluorine compounds to provide liquid repellency, then sub-pixels of different light-emission colors are effectively separated, but ink applied to adjacent sub-pixels is repelled causing defective formation of organic functional layers
Solution Approach 1:
The patent introduces an inorganic bank layer as an intermediary between the organic fluorine compound second banks and the organic functional layers. This inorganic layer acts as a mediator that prevents direct harmful interaction between the fluorine compound and the organic material, allowing the organic functional layers to form properly without being repelled by the fluorine-based banks while still maintaining the sub-pixel separation function.
Solution Approach 2:
The patent converts the harmful liquid repellency effect of the organic fluorine compound into a beneficial separation mechanism. By using the fluorine compound in the second banks, the patent achieves effective separation of sub-pixels with different light-emission colors, while the inorganic bank layer prevents the harmful side effect of ink repulsion, thus transforming the potential harm into a useful separation function.
2Ease of manufacture
If second banks have high liquid repellency to separate ink between adjacent sub-pixels, then color separation is improved, but organic functional layers fail to form completely in some regions
Solution Approach 1:
The inorganic bank layer serves as an intermediary that allows the second banks to maintain their liquid repellency for ink separation while preventing this repellency from interfering with organic functional layer formation. The inorganic layer decouples the separation function from the harmful repulsion effect, enabling both goals to be achieved simultaneously.
3Reliability
If organic bank layers are used in first banks, then sub-pixels of the same light-emission color are separated, but the organic fluorine compound in second banks causes ink repellency at intersection regions
Solution Approach 1:
The inorganic bank layer introduced in the first banks acts as a protective intermediary that prevents the organic fluorine compound from directly contacting the ink in regions where first and second banks intersect. This mediator eliminates the harmful repulsion effect while preserving the separation function of both bank systems.
Solution Approach 2:
The patent applies different materials to different parts of the bank structure. The inorganic bank layer is specifically positioned at the intersection regions where harmful repulsion occurs, while the organic bank layers maintain their separation function in other regions. This localized material differentiation resolves the contradiction by addressing the problem only where it occurs.
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 configuration ensures uniform light emission across all sub-pixels by preventing ink repellency and ensuring complete formation of the organic functional layers, thus eliminating uneven light emission.
Implementation Method 1
Incorporating an inorganic bank layer, such as silicon nitride or silicon oxide, on top of the organic bank layer in the first banks reduces the affinity between the organic fluorine compound of the second banks and the inorganic material, allowing ink to spread evenly
Implementation Method 2
the second banks have liquid repellency. Thus, when forming the organic functional layer by a printing method, the second banks may be considered to separate ink applied to adjacent sub-pixels
Data Source
AI summary
An organic light-emitting device including a substrate, first electrodes, first banks extending in a first direction, second banks extending in a second direction, organic functional layers each including an organic light-emitting layer, and a second electrode. The second banks include an organic fluorine compound, and have portions intersecting with and disposed above the first banks. Each of the first banks includes an organic bank layer including an organic material and an inorganic bank layer disposed on the organic bank layer. For each of the first banks, an uppermost surface thereof is a surface of the inorganic bank layer included therein.