OLED Dent Electrode Curvature Controls Color Shift
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Solution Overview
Problem
Conventional OLED displays experience color shift and efficiency deterioration due to varying distances between electrodes, which affects light emission and is exacerbated by processing errors.
Innovation Solution
The OLED display incorporates a substrate with a first electrode featuring a dent portion with a curved side, a pixel defining layer exposing the electrode, and a common electrode, maintaining a uniform distance to control color shift and enhance light emission efficiency by reflecting light in various directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional OLED displays use flat electrodes with uniform thickness, then the structure is simple and easy to manufacture, but the distance between electrodes varies with viewing angle causing color shift
Solution Approach 1:
The first electrode is designed with a dent portion having a curved side surface instead of a flat surface. This curvature causes light to reflect in various directions, maintaining uniform optical path length from the organic emission layer to the viewer across different viewing angles, thereby eliminating color shift while keeping the manufacturing process compatible with conventional techniques.
2Productivity
If the distance between first electrode and common electrode is increased to improve light emission efficiency, then light emission efficiency improves, but the device thickness increases
Solution Approach 1:
Instead of increasing the vertical distance between electrodes to improve light emission, the invention introduces a horizontal dimension through the dent portion. The curved side surface of the dent creates multiple reflection paths that extend the optical path length within the same vertical thickness, thereby improving light emission efficiency without increasing device thickness.
3Manufacturing precision
If processing errors cause variation in electrode distances, then manufacturing tolerance is relaxed, but light emission efficiency deteriorates
Solution Approach 1:
The invention changes the geometric parameter of the first electrode from a flat surface to a curved surface with a dent portion. This parameter change makes the optical path length insensitive to variations in the vertical distance between electrodes, so even when processing errors cause distance variations, the light emission efficiency remains stable because the curved surface compensates for these variations through its reflection geometry.
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 configuration effectively controls color shift and improves light emission efficiency by maintaining consistent distances between electrodes, even when processing errors occur, resulting in improved display quality and flexibility.
Implementation Method 1
improving efficiency of light emitted by an organic emission layer... maintaining a uniform distance to control color shift and enhance light emission efficiency by reflecting light in various directions
Data Source
AI summary
An organic light emitting diode display including a substrate, a first electrode disposed on the substrate, a second electrode disposed on the substrate and separated from the first electrode, a pixel defining layer disposed on the first electrode and the second electrode, a first organic emission layer disposed on the first electrode corresponding to the first opening, a second organic emission layer disposed on the second electrode corresponding to the second opening, and a common electrode disposed on the first organic emission layer and the second organic emission layer. The first electrode includes a first dent portion. The second electrode includes a second dent portion having a different size from the first dent portion. The pixel defining layer includes a first opening exposing the first electrode corresponding to the first dent portion and a second opening exposing the second electrode corresponding to the second dent portion.