Micro-LED Assembly Wiring Layout for Precise Self-Alignment
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Solution Overview
Problem
Micro-LED displays face challenges in accurately transferring millions of micro-LEDs to a display panel due to corrosion of assembly wiring and potential misalignment during self-assembly, leading to electrical short-circuits and assembly defects.
Innovation Solution
A display device design featuring first and second assembly wirings with a reverse taper-shaped structure, a planarization layer with tapered openings, and a light-emitting device positioned within, utilizing conductive and clad layers to minimize spacing and enhance assembly precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the self-assembly method is used to transfer micro-LEDs, then large-screen display devices can be implemented, but the assembly wiring is corroded by the fluid causing electrical short-circuits and assembly defects
Solution Approach 1:
A transfer substrate is introduced as an intermediary carrier to hold micro-LEDs during the self-assembly process. The micro-LEDs are transferred from the transfer substrate to the final display substrate, preventing direct contact between the fluid and the assembly wiring on the display substrate. This mediator approach enables fluid-based self-assembly while protecting the electrical wiring from corrosion.
2Manufacturing precision
If the opening size for the light emitting device is reduced, then resolution is improved, but the exposure device performance limitations make it difficult to achieve precise positioning
Solution Approach 1:
The patent introduces a transfer substrate as an additional dimensional layer in the manufacturing process. Precise positioning is achieved on the transfer substrate before transferring to the final substrate, effectively decoupling the positioning precision requirement from the opening size limitation of the exposure device. This dimensional approach allows smaller openings while maintaining positioning accuracy.
3Area of moving object
If the spacing between assembly wirings is reduced, then device density is improved, but misalignment during self-assembly causes assembly defects
Solution Approach 1:
The transfer substrate is prepared in advance with precise positioning structures and patterns before the self-assembly process. This preliminary preparation establishes accurate reference positions that guide the light emitting devices to their correct locations, enabling reduced wiring spacing while maintaining alignment precision through pre-established positioning references.
Data Source
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AI summary
A display device according to an embodiment includes a substrate, first assembly wiring and second assembly wiring that are spaced apart from each other on the substrate and each include a conductive layer and a clad layer on the conductive layer, a structure that is in contact with the second assembly wiring and has a reverse taper shape, a planarization layer that is disposed on the first assembly wiring and the second assembly wiring and has an opening, and a light emitting device that is disposed inside the opening and has a first electrode overlapping the first assembly wiring and the second assembly wiring, wherein the structure is disposed to cover a portion of an upper surface of the conductive layer of the second assembly wiring.