OLED Step Difference Compensation Pattern for Color Shift
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices experience color shifts due to non-uniform pixel electrode structures, leading to asymmetric light emission that varies with viewing angle.
Innovation Solution
Incorporating a step difference compensation pattern with a polygonal shape, made of the same material as the conductive lines, to offset asymmetry and imbalance in the pixel electrode structure, ensuring uniform light emission across different viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional pixel electrode structure is used, then the device structure is simple, but color shift occurs depending on viewing angle
Solution Approach 1:
The patent introduces asymmetric step difference compensation patterns (first, second, and third patterns with different lengths and positions) to counterbalance the inherent asymmetry in the pixel electrode structure. These patterns are deliberately designed with unequal dimensions on different sides of the pixel electrode to compensate for the non-uniform lower portion, thereby achieving uniform light emission across different viewing angles without increasing overall device complexity
Solution Approach 2:
The step difference compensation patterns are formed in advance during the manufacturing process, before the pixel electrode is deposited. These patterns create a pre-compensated surface that anticipates and counteracts the asymmetry that would otherwise cause color shift, allowing the pixel electrode to be formed uniformly without requiring post-manufacturing adjustments
2Ease of manufacture
If the pixel electrode lower portion is non-uniform, then the manufacturing process is simpler, but light emission becomes asymmetric
Solution Approach 1:
The patent performs preliminary action by forming step difference compensation patterns on the substrate before depositing the pixel electrode. These patterns create a pre-compensated topography that ensures uniform light emission when the pixel electrode is formed, eliminating the need for complex post-processing or adjustment of the pixel electrode itself while maintaining manufacturing simplicity
Solution Approach 2:
The step difference compensation patterns are strategically positioned at specific locations (first, second, and third patterns with different orientations and lengths) where asymmetry needs to be compensated. Each pattern has locally optimized dimensions and positions tailored to compensate for specific asymmetries in different regions of the pixel electrode, achieving uniform overall light emission through localized corrections
Data Source
AI summary
An organic light emitting display device includes a step difference compensation pattern that may reduce imbalance or asymmetry below a pixel electrode. The step difference compensation pattern is on a first protection layer and is separated from a conductive line. A second protection layer is on the conductive line and the first step difference compensation pattern. An organic light emitting layer is between the first electrode and a second electrode. The first electrode is on the second protection layer and overlaps at least a part of the conductive line and at least a part of the first step difference compensation pattern.