Tiled Display Pad Electrode Capping for Seamless Low-Resistance Bonding
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Solution Overview
Problem
Large-sized display devices face increased defect rates of light emitting elements due to the number of pixels, leading to reduced productivity and reliability, and the seams between connected display devices cause a sense of disconnection in the image, detracting from immersion.
Innovation Solution
A display device design featuring a capping layer that covers the pad electrode, with a first and second contact hole configuration, and a flexible film connection through these holes, reducing contact resistance and protecting the pad electrode from external environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large-sized display device is manufactured with increased number of pixels, then the display size is improved, but the defect rate of light emitting elements increases
Solution Approach 1:
The large display device is divided into multiple small display modules that are connected together to form the complete display. Each module contains a reduced number of pixels, which maintains lower defect rates while the combined modules achieve the desired large display size. The segmentation allows each module to be manufactured with higher reliability while collectively providing the large-area display function.
2Area of stationary object
If multiple display devices are connected to form a tiled display, then the display size is improved, but visible seams appear between devices reducing image immersion
Solution Approach 1:
Multiple display modules are merged together with their boundary portions closely aligned to form a unified large display. The connection structures include conductive adhesives and bonding layers that integrate the modules into a single coherent visual output, minimizing visible seams and maintaining image continuity across the entire display area.
3Ease of manufacture
If the pad electrode is exposed without protection, then the manufacturing process is simplified, but the pad electrode is damaged during etching and external exposure
Solution Approach 1:
A protective capping layer is formed over the pad electrode before subsequent etching and manufacturing steps. This preliminary protective action prevents damage to the pad electrode during processing and external exposure, while the layer is later removed or opened to expose the pad electrode for electrical connection. This approach maintains manufacturing simplicity while ensuring electrode protection.
4Reliability
If the pad electrode is directly exposed, then contact resistance is reduced, but the pad electrode is vulnerable to external environment damage
Solution Approach 1:
A conductive capping layer serves as an intermediary between the pad electrode and the external environment. This layer provides electrical connection functionality while simultaneously protecting the pad electrode from environmental damage. The capping layer maintains low contact resistance through its conductive properties while acting as a protective barrier against moisture, oxidation, and other harmful external factors.
Data Source
AI summary
A display device, a method of manufacturing the same and a tiled display device including the same are provided. The display device includes a first substrate including a first contact hole, a first barrier insulating layer disposed on the first substrate and including a second contact hole overlapping the first contact hole in a thickness direction, a capping layer disposed on the first barrier insulating layer, at least a portion of the capping layer being disposed in the second contact hole and the first contact hole, a pad electrode disposed on the capping layer, a display layer disposed on the pad electrode, and a flexible film disposed under the first substrate and electrically connected to the pad electrode through the first contact hole and the second contact hole.