Electroactive Layer Flat Profile via Vacuum Drying
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Solution Overview
Problem
Existing liquid deposition processes for forming electroactive layers in electronic devices often result in non-uniform film thickness, leading to adverse effects such as color variation and reduced efficiency in OLEDs due to surface non-uniformities and differences in evaporation rates.
Innovation Solution
A process involving the deposition of a liquid composition onto a workpiece, followed by controlled temperature and vacuum treatment to form a partially dried layer, and subsequent heating to achieve a substantially flat electroactive layer with no greater than ±15% thickness variation over 90% of the layer area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid composition is deposited onto workpiece to form electroactive layer, then device performance is improved, but film thickness uniformity deteriorates leading to color variation and reduced efficiency
Solution Approach 1:
The patent applies a preliminary action by depositing a planarization layer before the electroactive layer. This planarization layer is formed to compensate for surface non-uniformities of the substrate, creating a flat surface that ensures uniform thickness of the subsequent electroactive layer when deposited by liquid deposition techniques.
Solution Approach 2:
The patent changes the physical and chemical parameters of the liquid composition, including viscosity, surface tension, and solvent composition. By optimizing these parameters, the liquid composition achieves uniform spreading and evaporation rates, resulting in uniform film thickness while maintaining device performance.
2Device complexity
If liquid deposition technique is used to form electroactive layer, then manufacturing complexity is reduced, but film profile uniformity deteriorates
Solution Approach 1:
The patent modifies parameters of the liquid composition such as viscosity and surface tension to control wetting and evaporation behavior. These parameter changes enable the liquid deposition process to produce uniform film profiles without requiring complex additional equipment or process steps.
Solution Approach 2:
The patent employs continuous liquid deposition techniques where the liquid composition is continuously applied and dried in a controlled environment. This continuous process maintains uniform evaporation rates across the film area, ensuring profile uniformity while keeping the manufacturing process simple and efficient.
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 process ensures a uniform electroactive layer with improved device performance by maintaining a flat profile, enhancing efficiency and lifetime by minimizing thickness variations across the film area.
Implementation Method 1
treating the wet layer on the workpiece at a controlled temperature in the range of −25 to 80° C. and under a vacuum in the range of 10−6 to 1,000 Torr, for a first period of 1-100 minutes, to form a partially dried layer
Implementation Method 2
heating the partially dried layer to a temperature above 100° C. for a second period of 1-50 minutes to form a dried layer
Data Source
AI summary
There is provided a process for forming a layer of electroactive material having a substantially flat profile. The process includes the steps of providing a workpiece having at least one active area; depositing a liquid composition including the electroactive material onto the workpiece in the active area, to form a wet layer; treating the wet layer on the workpiece at a controlled temperature in the range of −25 to 80° C. and under a vacuum in the range of 10−6 to 1,000 Torr, for a first period of 1-100 minutes, to form a partially dried layer; and heating the partially dried layer to a temperature above 100° C. for a second period of 1-50 minutes to form a dried layer.