OLED Planarization Layers for Color Separation Control
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Solution Overview
Problem
Display devices, particularly OLEDs, face challenges with color separation phenomena due to step differences in electrode surfaces, which necessitate the use of polarizers, increasing production costs and device thickness.
Innovation Solution
The implementation of a display device structure with a substrate, source and drain electrodes, and planarization layers, including black pigments, to minimize step differences between electrode surfaces, potentially eliminating the need for polarizers by absorbing external light and enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional OLED structure with step differences in electrode surfaces is used, then device structure is simpler, but color separation phenomena occur requiring polarizers which increase production costs and device thickness
Solution Approach 1:
The patent applies preliminary action by forming planarization layers before the emission layer to pre-compensate for step differences caused by source and drain electrodes. This preliminary planarization prevents color separation phenomena from occurring in the first place, eliminating the need for subsequent polarizer layers and reducing both production costs and device thickness.
Solution Approach 2:
The patent introduces planarization layers as intermediary structures between the electrode layer and the emission layer. These intermediary layers fill the step differences created by the electrodes, providing a flat surface for subsequent layer deposition and preventing color separation without requiring polarizers.
2Object-affected harmful factors
If polarizers are added to eliminate color separation, then color separation phenomena are reduced, but device thickness and production costs increase
Solution Approach 1:
The patent extracts and eliminates the need for polarizer layers by addressing the root cause of color separation through planarization. By removing the harmful step differences at their source, the solution extracts the unnecessary polarizer components, thereby reducing device thickness and production costs while maintaining display quality.
3Object-affected harmful factors
If planarization layers are added to minimize step differences, then color separation phenomena are reduced, but device structure becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the surface topology parameter through planarization layers. By changing the surface height parameter from stepped to flat, the solution eliminates color separation phenomena while maintaining overall structural simplicity, as the planarization process integrates well with existing OLED manufacturing workflows.
4Object-affected harmful factors
If step differences between electrode surfaces are minimized, then color separation phenomena are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces planarization layers as intermediary structures that compensate for electrode step differences. This intermediary approach relaxes manufacturing precision requirements because the planarization process can accommodate reasonable variations in electrode fabrication, providing a buffer that maintains display quality without demanding extreme precision in earlier manufacturing steps.
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 approach reduces color separation phenomena, allowing for the omission of polarizers, thereby decreasing production costs and thickness of the display device while maintaining image quality.
Implementation Method 1
forming a first planarization layer on the source electrode and the drain electrode such that a step difference between a top of the first planarization layer and a top of the drain electrode is 100 Å or less
Implementation Method 2
including black pigments, to minimize step differences between electrode surfaces, potentially eliminating the need for polarizers by absorbing external light
Data Source
AI summary
A display device including a substrate, a source electrode and a drain electrode on the substrate, the source electrode and the drain electrode being spaced apart from each other, a first layer on the source electrode or the drain electrode, a second layer directly on the first layer, and a first electrode on the second layer. A step difference between a top of the first layer and a top of the drain electrode is 100 Å or less.