Recess Structure With Stacked Branch Dams For OLED Ink Deposition
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Solution Overview
Problem
The existing print deposition processes for OLED displays face challenges in achieving uniform thickness of organic functional layers due to varying hydrophilic properties of inks, leading to poor contact angles and subsequent display effects.
Innovation Solution
A recess structure with stacked branch dam layers is introduced, where the contact angle between the ink and the inclined inner surface of the recess increases gradually from the lowermost to the uppermost layer, limiting the ink's climbing height and improving thickness uniformity and photoelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-layer dam structure is used with a fixed inclined angle, then the manufacturing process is simple, but the contact angle between ink and dam surface cannot be optimized, leading to poor thickness uniformity of organic functional layers
Solution Approach 1:
The dam structure is divided into multiple stacked branch dam layers (first, second, and third branch dam layers) with different inclined angles. Each layer segment controls the ink spreading at different height levels, allowing the ink to form a meniscus that maintains a consistent contact angle across varying dam geometries, thereby achieving uniform film thickness despite the multi-layered complex structure.
Solution Approach 2:
Different branch dam layers are designed with different inclined angles (α1, α2, α3) to create locally optimized surfaces for ink deposition. The first branch dam layer has a larger inclined angle to prevent excessive ink climbing at the base, while upper layers have progressively smaller angles to maintain proper contact angle control, ensuring uniform thickness distribution across the entire recess area.
2Manufacturing precision
If the inclined angle of the dam inner circumferential surface is small, then the contact angle between ink and dam surface increases, but the ink climbs too high along the inner circumferential surface, resulting in poor thickness uniformity
Solution Approach 1:
The dam structure transitions from a static single-angle design to a dynamic multi-angle configuration where the inclined angle varies with height. The branch dam layers are arranged such that the inclined angle decreases from the first to the third layer, dynamically adapting the surface geometry to control ink spreading behavior at different elevation levels and achieving consistent contact angle control throughout the recess.
3Manufacturing precision
If ink with good hydrophilic property is used, then the ink spreads easily on the substrate, but it climbs too high along the inner circumferential inclined surface of the dam, resulting in a contact angle that is too small and poor thickness uniformity
Solution Approach 1:
The dam structure parameters (inclined angles of branch dam layers) are specifically optimized to compensate for the high hydrophilicity of the ink. By setting the first branch dam layer with a larger inclined angle and upper layers with progressively smaller angles, the structure creates geometric constraints that prevent excessive ink climbing, maintaining the contact angle within the optimal range (30°-60°) even for inks with strong hydrophilic properties.
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 recess structure enhances the uniformity of organic functional layers and improves the photoelectric properties of OLED displays by controlling the ink's contact angle with the dam layers, resulting in better display quality.
Implementation Method 1
forming a contact angle with an ink increasing gradually from a lowermost branch dam layer to an uppermost branch dam layer
Data Source
AI summary
The invention provides a recess structure for print deposition process and manufacturing method thereof. By disposing the dam (2) enclosing the recess (3) as comprising at least two stacked branch dam layers, and increasing the contact angle between the inclined inner circumferential surface of recess (3) enclosed by the branch dam layers and ink in a layer-by-layer manner, to limit height the ink able to climb on the inclined inner circumferential surface of the recess (3), the invention can improve the thickness uniformity of the organic functional layers printed in the recess and the photoelectric properties of organic functional layers. The recess (3) fabricated by the manufacturing method can limit height the ink able to climb on inclined inner circumferential surface of the recess (3) to improve the thickness uniformity of the organic functional layers printed in the recess and the photoelectric properties of organic functional layers.