Pad Electrode Structure for Mask-Reduced ILED Display Fabrication
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Solution Overview
Problem
Existing display device fabrication processes require separate mask processes for forming pad electrodes, which increases complexity and reduces efficiency.
Innovation Solution
A new pad electrode structure is introduced where layers in the display area and pad area are merged, allowing pad electrodes to be formed using the same process, eliminating the need for a separate mask process for pad electrodes, thus simplifying the fabrication of display devices with inorganic light-emitting diodes (ILEDs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate mask processes are used for forming pad electrodes, then the fabrication process can be more precise in controlling pad electrode formation, but the device complexity and number of process steps increase
Solution Approach 1:
The patent merges the display area electrode formation process with the pad area electrode formation process into a single unified process. The same electrode layer is continuously formed across both the display area and pad area without interruption, eliminating the need for separate mask processes for pad electrodes while maintaining formation precision through consistent material deposition and patterning conditions.
2Manufacturing precision
If separate mask processes are used for forming pad electrodes, then the pad electrodes can be precisely positioned, but the productivity and fabrication efficiency decrease
Solution Approach 1:
The patent combines multiple electrode formation operations into a single continuous process step. By forming electrodes in the display area and pad area simultaneously in one process run, the patent eliminates repeated mask alignment and material deposition cycles, thereby maintaining positioning precision while significantly improving fabrication throughput and efficiency.
3Productivity
If layers in display area and pad area are merged, then the number of mask processes is reduced and fabrication efficiency improves, but the protection of wire pads from subsequent processes becomes more challenging
Solution Approach 1:
The patent applies a protective layer over the wire pads in the pad area before the electrode formation process begins. This preliminary protective action ensures that wire pads are shielded from subsequent processing steps such as etching, deposition, or cleaning operations, while still allowing the electrode layers to be formed continuously across both display and pad areas in a unified process.
Data Source
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AI summary
A display device comprising a first substrate comprising a display area and a pad area; a wire pad on the first substrate in the pad area; electrodes on the display area and spaced apart from each other; a pad electrode base layer directly on the wire pad, having a greater width than the wire pad, and covering sides of the wire pad; light-emitting elements on the electrodes in the display area; and a pad electrode upper layer in the pad area and directly contacting the pad electrode base layer, wherein the pad electrode base layer comprises the same material as the electrodes.