OLED Backplate Surface Property Preservation During Plasma Cleaning
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Solution Overview
Problem
The existing methods for manufacturing OLED backplates fail to maintain the hydrophobic top surface and hydrophilic side surfaces of the pixel defined layer required for ink-jet printing, as oxygen plasma treatment alters the surface properties, affecting the subsequent ink-jet printing process.
Innovation Solution
A method involving the formation of a protective photoresist layer with a through opening that exposes the pixel opening, allowing oxygen plasma treatment to remove photoresist residues from the electrode layer while preserving the hydrophobic top surface and hydrophilic side surfaces of the pixel defined layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If oxygen plasma treatment is performed on the entire surface to remove photoresist residues, then the photoresist residues on the electrode layer are removed, but the surface properties of the pixel defined layer are altered (both top and side surfaces become hydrophilic)
Solution Approach 1:
The patent applies different surface properties to different parts of the pixel defined layer: the top surface is made hydrophobic while the side surfaces are made hydrophilic. This is achieved by controlling the photoresist coating and development process to create differential surface characteristics, allowing the top surface to repel ink droplets while side surfaces promote uniform film formation.
Solution Approach 2:
The patent performs preliminary actions before oxygen plasma treatment to preserve the hydrophobic property of the top surface. Specifically, the top surface is treated with a hydrophobic coating or plasma treatment before the final cleaning step, creating a protective layer that prevents the oxygen plasma from altering the hydrophobic character while still allowing photoresist removal.
2Ease of operation
If the top surface of the pixel defined layer is made hydrophobic to enable ink flow, then ink droplets can flow into pixel grooves easily, but the side surfaces must be hydrophilic to ensure uniform film deployment
Solution Approach 1:
The patent creates different surface properties at different locations of the pixel defined layer. The top surface is treated to be hydrophobic (water-repelling) with a contact angle greater than 90 degrees, enabling ink droplets to flow smoothly into the pixel groove. The side surfaces are treated to be hydrophilic (water-attracting) with a contact angle less than 40 degrees, ensuring uniform film deployment and preventing excessive contact angle formation.
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 method enables efficient ink-jet printing by maintaining the desired surface properties, resulting in a more stable and long-lasting OLED device with improved performance.
Implementation Method 1
applying an oxygen plasma onto the entire surface of the TFT substrate, and treating the electrode layer by the oxygen plasma to remove the photoresist residues thereon
Implementation Method 2
the top surface of the PDL has a hydrophobic property, such that ink droplets containing a dissolved OLED material can be easily flowed in a pixel groove defined by the PDL
Implementation Method 3
the side surfaces of the PDL have a hydrophilic property, such that the droplets can be very uniformly deployed in the pixel groove
Data Source
AI summary
A method for manufacturing an OLED backplate and a method for manufacturing an OLED panel are provided. In the method for manufacturing the OLED backplate of the present disclosure, a protective photoresist layer is manufactured on a pixel defined layer in which the top surface thereof has a hydrophobic property and the side surfaces thereof have a hydrophilic property before an electrode layer is treated by an oxygen plasma to remove photoresist residues, thereby the top surface of the pixel defined layer covered by the protective photoresist layer is not affected by the oxygen plasma in the proceeding of an oxygen plasma treatment, and still has the hydrophobic property. Therefore, the properties of the top surface of the pixel defined layer having the hydrophobic property and the side surfaces of the pixel defined layer having the hydrophilic property are kept while the photoresist residues on the electrode layer is removed, and thus an OLED device can be easily manufactured by an ink-jet printing process.