OLED Partition Structure With Differential Etching for Reliable Conduction
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Solution Overview
Problem
The manufacturing of OLED display devices faces challenges in improving reliability due to issues with the etching process, particularly with the use of mixed acids containing phosphoric acid, nitric acid, and acetic acid, which can affect the conductivity and structure of the electrodes and organic layers.
Innovation Solution
The display device incorporates a partition structure with a conductive bottom layer and a stem layer, where the bottom layer has a smaller etching rate than the stem layer, and is formed of materials like titanium or titanium nitride, and the stem layer is made of aluminum or its alloys, ensuring effective contact and conductivity between electrodes and organic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer conductive structure is used for the partition, then the manufacturing process is simpler, but the etching rate control and conductivity reliability are insufficient
Solution Approach 1:
The partition is divided into two distinct layers: a first layer (stem layer) made of aluminum or aluminum alloy with high etching rate, and a second layer (bottom layer) made of titanium, tungsten, or their alloys with low etching rate. This segmentation allows each layer to perform its specific function - the first layer ensures proper etching and contact hole formation, while the second layer maintains structural integrity and conductivity, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
The partition employs a composite structure combining different materials with complementary properties. The aluminum-based first layer provides excellent etchability and conductivity, while the titanium or tungsten-based second layer offers structural stability and resistance to etching. This composite material approach enables the partition to simultaneously achieve reliable conduction and controlled etching behavior without requiring overly complex single-material solutions.
2Manufacturing precision
If the stem layer has the same etching rate as the bottom layer, then the manufacturing process is simpler, but the pixel aperture formation precision deteriorates
Solution Approach 1:
Different layers of the partition are assigned different etching rates according to their specific functional requirements. The first layer (stem layer) is designed with high etching rate to facilitate contact hole formation and organic layer penetration, while the second layer (bottom layer) is designed with low etching rate to maintain structural integrity during the etching process. This local differentiation of etching properties enables precise pixel aperture formation without requiring complex multi-step etching processes.
3Reliability
If the partition structure is simplified, then the manufacturing is easier, but the conductivity between electrodes cannot be maintained
Solution Approach 1:
The partition structure is pre-configured with two layers having different etching rates before the etching process begins. This preliminary arrangement ensures that during subsequent manufacturing steps, the first layer will be selectively etched to form conductive pathways while the second layer remains intact to maintain structural support. This pre-planned differentiation eliminates the need for complex post-manufacturing adjustments to ensure conductivity, thereby maintaining ease of manufacture while guaranteeing reliable electrode connection.
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 enhances the reliability of the OLED display device by maintaining the integrity of the electrodes and organic layers during etching, preventing conduction failure and allowing for precise control of the partition's shape, thus improving the overall performance and durability of the device.
Implementation Method 1
the bottom layer is formed of a material which has a smaller etching rate to a mixed acid containing phosphoric acid, nitric acid, and acetic acid than the stem layer
Data Source
AI summary
According to one embodiment, a display device comprises a first lower electrode, a rib including a first pixel aperture, a partition including a lower portion on the rib and an upper portion protruding from a side surface of the lower portion, a first upper electrode, and a first organic layer between the first lower electrode and the first upper electrode. The lower portion includes a bottom layer and a stem layer on the bottom layer. The bottom layer is formed of a material which has a smaller etching rate to a mixed acid containing phosphoric acid, nitric acid, and acetic acid than the stem layer and which is conductive.