Segmented Dam Structure for Uniform OLED Ink Film Formation
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Solution Overview
Problem
The existing methods for manufacturing OLED display elements face challenges in achieving uniform film thickness during the printing of different organic layers due to the varying hydrophilic-hydrophobic properties of the inks, which is difficult to manage with a single material for the dam structures.
Innovation Solution
A groove structure with a dam comprising multiple layers of silicon nitride and silicon oxide, where the inclined surfaces are treated with oxygen plasma and silane reagents to create hydrophilic and hydrophobic properties, allowing for the adjustment of contact angles and preventing nonuniform film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single material is used to manufacture the dam, then the device complexity is reduced, but the manufacturing precision of film thickness deteriorates due to inability to satisfy different hydrophilic-hydrophobic requirements
Solution Approach 1:
The dam is divided into multiple layers (first dam layer and second dam layer) with different materials. The first dam layer uses a hydrophobic material while the second dam layer uses a hydrophilic material, allowing each layer to independently control ink behavior for different ink types, thereby achieving uniform film thickness without using a single complex material
Solution Approach 2:
Different portions of the dam structure are assigned different hydrophilic-hydrophobic properties based on local requirements. The first dam layer provides hydrophobic properties for hydrophobic inks, while the second dam layer provides hydrophilic properties for hydrophilic inks, ensuring optimal local control of ink flow and contact angle for each material type
2Reliability
If the dam lateral side is made hydrophobic, then hydrophobic ink contact angle is controlled, but hydrophilic ink film thickness deteriorates due to excessive contact angle
Solution Approach 1:
The dam structure is segmented into two functional layers: the first dam layer with hydrophobic properties that controls hydrophobic ink contact angle, and the second dam layer with hydrophilic properties that ensures proper wetting and uniform film thickness for hydrophilic inks. This segmentation allows independent optimization for each ink type
Solution Approach 2:
The dam is constructed as a composite structure combining materials with different hydrophilic-hydrophobic characteristics. The first dam layer uses hydrophobic material while the second dam layer uses hydrophilic material, creating a composite dam that can simultaneously satisfy the contradictory requirements of different ink materials
3Reliability
If the dam lateral side is made hydrophilic, then hydrophilic ink contact angle is controlled, but hydrophobic ink film thickness deteriorates due to excessive contact angle
Solution Approach 1:
The dam is divided into functional layers where the second dam layer with hydrophilic properties controls hydrophilic ink behavior, while the first dam layer with hydrophobic properties prevents excessive contact angle for hydrophobic inks, ensuring both ink types achieve uniform film thickness
Solution Approach 2:
A composite dam structure is employed where the first dam layer provides hydrophobic characteristics for hydrophobic ink compatibility, and the second dam layer provides hydrophilic characteristics for hydrophilic ink compatibility, resolving the contradiction through material composition
4Reliability
If the dam upper surface is made hydrophobic, then ink flow into groove is prevented, but film formation uniformity deteriorates due to ink remaining on dam surface
Solution Approach 1:
The dam structure segments the control of ink behavior: the upper surface of the first dam layer is made hydrophobic to contain ink within the groove and prevent overflow, while the lateral sides are made hydrophilic to ensure proper wetting and uniform film formation, achieving both ink containment and uniformity through functional segmentation
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 groove structure effectively prevents nonuniform film thickness by allowing ink to flow correctly into the grooves, ensuring consistent film formation across different layers, even with varying ink properties.
Implementation Method 1
The inclined circumferential surface of the groove, which is surrounded by the branch dam layer manufactured with silicon oxide, and an upper surface of the top side branch dam layer are covered with monomer silane reagent
Implementation Method 2
an inclined circumferential surface of the groove, which is surrounded by the branch dam layer manufactured with silicon nitride, is a hydrophilic surface
Data Source
AI summary
The present invention provides a groove structure employed for printing film formation, wherein the groove structure is located on a substrate, comprises a dam and a groove formed by the dam surrounding, and the dam comprises at least two layers of branch dam layers, which are stacked up, and material of the branch dam layers is silicon nitride or silicon oxide, and material of a top side branch dam layer is silicon oxide, wherein the inclined circumferential surface of the groove, which is surrounded by the branch dam layer manufactured with silicon oxide and the upper surface of the top side branch dam layer are hydrophobic surfaces, and an inclined circumferential surface of the groove, which is surrounded by the branch dam layer manufactured with silicon nitride, is a hydrophilic surface.