OLED Barrier Structure Suppresses Ink Climbing
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Solution Overview
Problem
Inkjet printing of organic light emitting material film layers in OLED displays results in uneven film formation due to ink droplets climbing along sidewalls of the pixel defining layer, leading to abnormal displays and reduced luminous efficiency, as the upper surface of the pixel defining layer is lyophobic while other portions are lyophilic.
Innovation Solution
A substrate with a barrier structure attached to the sidewalls of the pixel defining layer, where the distance from the upper surface of the barrier structure to the base substrate is less than from the pixel defining layer, and at least part of its surfaces are lyophobic, made from the same material as the pixel defining layer, including fluorine-containing resin, to suppress the climbing of ink droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inkjet printing technology is used to manufacture the organic material film layer, then the organic material film layer can be formed, but ink droplets climb along the sidewalls of the pixel defining layer causing uneven film formation and abnormal displays
Solution Approach 1:
A barrier structure is introduced as an intermediary component between the pixel defining layer and the ink droplets. This barrier structure, made of fluorine-containing resin with lyophobic properties, acts as a mediator that prevents direct contact between the ink droplets and the sidewalls of the pixel defining layer, thereby stopping the climbing phenomenon while allowing the inkjet printing process to proceed
Solution Approach 2:
The surface energy parameters of the barrier structure are specifically designed to be lyophobic (water-repelling) through the use of fluorine-containing resin. By changing the surface energy parameters of the barrier structure, the ink droplets are prevented from adhering to and climbing along the sidewalls, thus improving film formation uniformity
2Object-generated harmful factors
If the pixel defining layer has a lyophobic upper surface, then ink droplet climbing is suppressed, but other portions need to be lyophilic for proper ink reception
Solution Approach 1:
The barrier structure is designed with local quality differentiation: the upper surface is made lyophobic to suppress ink droplet climbing, while the lower surface and sidewalls maintain appropriate wettability for structural integrity and ink reception. This local differentiation of surface properties allows the structure to perform multiple functions simultaneously
Solution Approach 2:
The barrier structure is segmented into distinct functional zones: the upper surface segment that repels ink droplets, and the lower segment that provides structural support and controlled ink interaction. This segmentation allows different parts of the same structure to have different surface properties tailored to their specific functions
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 barrier structure effectively reduces the climbing height of ink droplets, improving display uniformity and luminous efficiency by preventing ink accumulation on sidewalls and maintaining effective light emission areas.
Implementation Method 1
at least a part of surfaces of the barrier structure are lyophobic
Data Source
AI summary
A substrate, a method of preparing the substrate and a display device are provided. The substrate includes: a base substrate; a pixel defining layer on the base substrate, the pixel defining layer defining a plurality of opening regions arranged in an array, each of the plurality of opening regions having a plurality of sidewalls; and a barrier structure attached to at least one sidewall of at least one opening region. A distance from an upper surface of the barrier structure to the base substrate is less than a distance from an upper surface of the pixel defining layer to the base substrate, and at least a part of surfaces of the barrier structure are lyophobic.