Bi-directional OLED Electrode Patterning via Auxiliary Layer
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Solution Overview
Problem
Existing organic light-emitting display (OLED) technologies face challenges in efficiently patterning the reflective electrode for both top and bottom emission, which affects emission efficiency and brightness, and requires complex fine metal masks for precise patterning.
Innovation Solution
The solution involves forming a fourth electrode with a stronger adhesive force to the third electrode than to an auxiliary layer, using metals like magnesium, and patterning it without a separate mask by depositing metal simultaneously across regions, including the auxiliary layer, to improve emission efficiency and reduce wiring resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a separate fine metal mask is used for precise patterning of the reflective electrode, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the patterning function from a separate fine metal mask and integrates it into the auxiliary layer structure. The auxiliary layer is selectively removed in specific regions to expose the third electrode, which then serves as the patterned reflective electrode. This eliminates the need for a separate fine metal mask while maintaining precise patterning control.
Solution Approach 2:
The auxiliary layer is formed beforehand with specific material properties that enable selective removal. This preliminary preparation allows the fourth electrode to be deposited without requiring a separate patterning mask, as the auxiliary layer itself defines the pattern areas where the reflective electrode should be exposed.
2Use of energy by moving object
If the fourth electrode is made thicker in emission regions, then emission efficiency is improved, but transmissivity in transmission regions deteriorates
Solution Approach 1:
The fourth electrode is designed with spatially varying thickness: thicker in the first region (emission region) to enhance emission efficiency, and thinner or absent in the second region (transmission region) to maintain high transmissivity. This local differentiation of electrode thickness optimizes both emission and transmission performance in their respective regions.
3Reliability
If the fourth electrode is made thicker, then wiring resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The fourth electrode is merged with the auxiliary layer structure, where the auxiliary layer serves dual purposes: as a protective/functional layer and as a patterning template. This integration simplifies the overall manufacturing process by combining multiple functions into a single structural element, reducing the need for separate thick electrode deposition 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 simplifies the patterning process, enhances emission efficiency, and improves image quality by allowing for thicker fourth electrodes in emission regions while maintaining thinness in transmission regions, thus improving overall transmissivity and reducing voltage drop.
Implementation Method 1
An adhesive force of the fourth electrode to the third electrode may be stronger than that to the auxiliary layer
Implementation Method 2
by depositing metal simultaneously across regions, including the auxiliary layer
Data Source
AI summary
An organic light-emitting display apparatus includes a plurality of pixels, a plurality of first electrodes, a plurality of second electrodes, an intermediate layer, a third electrode, an auxiliary layer, and a fourth electrode. Each pixel includes a first region that emits light in a first direction and a second region that emits light in a second direction that is opposite to the first direction. The first electrodes are respectively located in the first region of each of the pixels. The second electrodes are respectively located in the second region of each of the plurality of pixels. The intermediate layer is on the plurality of first electrodes and the plurality of second electrodes, and includes an organic emission layer. The third electrode is on the intermediate layer and in the first and second regions. The fourth electrode is in the first region and contacts the third electrode.