Plasma-Treated Pixel Defining Layer Adhesion in OLED Displays
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Solution Overview
Problem
In organic light emitting display devices, weak adhesion between pixel defining layers can lead to peeling issues during manufacturing, affecting display quality and reliability.
Innovation Solution
Improving adhesion between the first and second pixel defining layers by creating a surface roughness on the upper surface of the first pixel defining layer, which increases the contact area and prevents peeling, using plasma treatment to enhance the surface roughness without damaging the underlying electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the pixel defining layer is formed by laminating two or more different kinds of layers, then the pixel defining layer can provide structural support and define pixel boundaries, but the bonding force between the different types of layers may be weak causing peeling during the process
Solution Approach 1:
The patent changes the surface roughness parameter of the first pixel defining layer by performing plasma treatment, which increases the surface area and creates mechanical interlocking with the second pixel defining layer, thereby improving adhesion strength without changing the fundamental layered structure
Solution Approach 2:
The patent replaces simple laminar bonding with plasma-treated surface bonding, where the plasma treatment modifies the surface chemistry and physics to create stronger interlayer adhesion through enhanced surface energy and roughness
2Strength
If plasma treatment is performed to increase surface roughness of the first pixel defining layer, then adhesion between pixel defining layers is improved, but there is a risk of damaging the underlying first electrode
Solution Approach 1:
The patent applies plasma treatment selectively to the upper surface of the first pixel defining layer, creating local surface modification only where needed for adhesion, while the underlying electrode remains unaffected due to the protective nature of the pixel defining layer structure
Solution Approach 2:
The pixel defining layer is formed first as a protective barrier before plasma treatment, preventing direct exposure and potential damage to the underlying electrode during the plasma treatment process
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
Stable formation of the organic layer and improved display quality and reliability by preventing peeling of the second pixel defining layer, maintaining consistent light emission and extending device lifetime.
Implementation Method 1
using plasma treatment to enhance the surface roughness without damaging the underlying electrode
Data Source
AI summary
A display device includes a substrate, a plurality of pixels on the substrate, a first electrode arranged for each pixel on the substrate, a pixel defining layer on the substrate along a boundary of each pixel and including an opening exposing the first electrode of the pixel, an organic layer on the first electrode in the opening of the pixel defining layer, and a second electrode on the organic layer, the pixel defining layer including a first pixel defining layer and a second pixel defining layer stacked on a surface of the first pixel defining layer, the surface of the first pixel defining layer including an upper surface and a side surface, and a surface roughness of the upper surface of the first pixel defining layer being greater than a surface roughness of the first electrode.