OLED Double Bank Structure for Thickness Uniformity
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Solution Overview
Problem
Organic light-emitting display devices face issues with thickness non-uniformity of the light emitting layer due to deposition method, which deteriorates display quality and leads to defects such as dark spots and reduced lifespan.
Innovation Solution
An organic light-emitting display device with a double bank structure, where the first bank layer has regions of different thicknesses to manage the deposition of organic light emitting materials, and the second bank layer is hydrophobic to prevent mixing of colors and ensure uniform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a mask is used to pattern light emitting layers in a large area display device, then the deposition coverage is improved, but the mask bends causing non-deposition of organic light emitting material at desired positions
Solution Approach 1:
The patent removes the mask component entirely from the deposition system, replacing it with a maskless deposition approach that uses a movable deposition source to pattern the light emitting layers directly onto the substrate without requiring a physical mask, thereby eliminating mask bending issues in large area devices
Solution Approach 2:
The patent replaces the mechanical mask system with a controlled deposition process that uses a movable deposition source and predefined deposition patterns to achieve precise patterning, substituting mechanical mask positioning with controlled material deposition dynamics
2Loss of energy
If a solution process is used to form the light emitting layer, then material use rate and thermal stability are improved, but thickness non-uniformity deteriorates display quality
Solution Approach 1:
The patent applies different deposition conditions and parameters to different regions of the substrate during the solution process, controlling the deposition rate, temperature, and other parameters locally to achieve uniform thickness across the entire large area substrate while maintaining the high material use rate benefits of the solution process
Solution Approach 2:
The patent introduces dynamic control elements to the solution process, including movable deposition sources, real-time monitoring, and adaptive deposition rate control, allowing the system to respond to local variations and maintain thickness uniformity throughout the deposition 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
The double bank structure enhances thickness uniformity of the light emitting layer, improving display quality by reducing luminance deviations and current density differences, thereby extending the lifespan of elements and increasing process yield.
Implementation Method 1
the second bank layer may have hydrophobicity
Data Source
AI summary
An organic light-emitting display device including a substrate on which a plurality of sub-pixels are arranged; a thin film transistor and a first electrode of an organic light-emitting diode connected to the thin film transistor, the thin film transistor and the organic light-emitting diode being disposed in each of the plurality of sub-pixels; a first bank layer disposed on the first electrode and exposing the first electrode; and a second bank layer disposed on the first bank layer and exposing the first bank layer and the first electrode. Further, the first bank layer includes first regions overlapping with via holes through which the thin film transistor is connected to the first electrode and second regions which are regions other than the first regions, and a thickness of the first regions is greater than a thickness of the second regions.