Display Pad Electrode Structure Without Separate Masking
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Solution Overview
Problem
Existing display device fabrication processes require separate mask processes for forming pad electrodes, which complicates the manufacturing and reduces efficiency.
Innovation Solution
A new pad electrode structure is introduced, where the pad electrodes are formed using the same process as the display area layers, including a pad electrode base layer and upper layer made of the same material as the electrodes, eliminating the need for a separate mask process in the pad area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate mask processes are used for forming pad electrodes, then the pad electrodes can be precisely formed, but the fabrication process becomes complex and less efficient
Solution Approach 1:
The patent merges the pad electrode formation process with the display area electrode formation process by using a common bank structure. The bank serves as a shared reference structure for both pad electrodes and display electrodes, allowing both to be formed in the same fabrication steps without requiring separate mask processes, thus reducing process complexity while maintaining precision
Solution Approach 2:
The bank structure is designed to serve multiple functions: it acts as a reference for positioning both pad electrodes and display area electrodes, provides structural support, and defines the spacing between electrodes. This multi-functional design eliminates the need for separate dedicated structures for pad electrode formation
2Manufacturing precision
If separate mask processes are used for forming pad electrodes, then the pad electrodes can be precisely formed, but the number of fabrication steps increases
Solution Approach 1:
The patent combines multiple electrode formation operations into a single fabrication sequence. By using the bank as a common reference structure, both pad electrodes and display electrodes are formed in the same steps, reducing the total number of fabrication steps while maintaining precise positioning through the bank's geometric constraints
3Device complexity
If pad electrodes are formed using the same process as display area layers, then the fabrication process is simplified, but the wire pads need protection from subsequent processes
Solution Approach 1:
The bank structure is formed beforehand to serve as a protective and reference structure. By establishing the bank first, subsequent electrode formation processes can proceed without directly exposing or damaging the wire pads, as the bank acts as a buffer and alignment reference that protects the underlying pad structures
Data Source
AI summary
A display device includes a first substrate, a wire pad in a pad area, first banks in a display area, electrodes on the first banks, a pad electrode base layer on the wire pad, having a greater width than the wire pad, and covering sides of the wire pad, a first insulating layer covering parts of the electrodes and part of the pad electrode base layer, light-emitting elements on the first insulating layer in the display area, respective ends of the light-emitting elements being on different electrodes, contact electrodes on the electrodes and contacting first ends of the light-emitting elements, and a pad electrode upper layer on the first insulating layer in the pad area and directly contacting the pad electrode base layer, wherein the pad electrode base layer includes the same material as the electrodes, and the pad electrode upper layer includes the same material as the contact electrodes.