Micro-LED Display Electrode Self-Alignment to Prevent Shorts
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Solution Overview
Problem
The technical challenge lies in efficiently assembling micro-LEDs for large displays, where the self-assembly method faces issues with corrosion of assembly wiring, electrical short circuits, misalignment of driving wiring, and defects due to the formation of contact electrodes on the wrong semiconductor layers, leading to reduced luminous efficiency and increased defects.
Innovation Solution
A display device and manufacturing method that self-aligns the contact electrode to connect only with the first semiconductor layer, using a substrate with spaced assembly wiring, a planarization layer, and a passivation layer to prevent corrosion and misalignment, allowing the contact electrode to be electrically connected only to the first semiconductor layer, and utilizing the assembly wiring as electrodes for both self-assembly and driving the light emitting device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the self-assembly method is used to transfer micro-LEDs to the display panel, then the assembly efficiency is improved, but the assembly wiring is corroded by the fluid causing electrical short circuits
Solution Approach 1:
A contact electrode is introduced as an intermediary component between the assembly wiring and the first semiconductor layer. This contact electrode serves as a protective intermediary that prevents direct contact between the assembly wiring and the fluid, thereby preventing corrosion and electrical short circuits while maintaining the self-assembly process efficiency
Solution Approach 2:
The contact electrode is formed in advance before the self-assembly process. By preliminarily establishing the contact electrode structure that connects the assembly wiring to the first semiconductor layer, the system prevents potential corrosion issues before they occur during the fluid-based self-assembly process
2Ease of manufacture
If the contact electrode is formed without precise alignment, then the manufacturing process is simplified, but misalignment with the first semiconductor layer causes electrical short circuits
Solution Approach 1:
The contact electrode structure is designed to self-align with the first semiconductor layer through the self-assembly process. The micro-LEDs automatically position themselves relative to the contact electrode during self-assembly, eliminating the need for complex external alignment mechanisms while ensuring precise electrical connection
Solution Approach 2:
The contact electrode is designed to establish an equipotential connection with the first semiconductor layer, ensuring proper electrical potential alignment. This design ensures that the contact electrode and first semiconductor layer are at the same electrical potential, preventing short circuits while maintaining manufacturing simplicity
3Ease of manufacture
If the contact electrode is formed on the second semiconductor layer, then the manufacturing process is simplified, but luminous efficiency decreases
Solution Approach 1:
The contact electrode is specifically positioned to contact only the first semiconductor layer, creating a localized electrical connection that preserves the optical properties of the second semiconductor layer. This local quality differentiation ensures that the contact electrode formation remains simple while preventing degradation of luminous efficiency by avoiding contact with the light-emitting second semiconductor layer
4Ease of manufacture
If the assembly wiring is exposed to fluid during self-assembly, then the self-assembly process is simplified, but corrosion of assembly wiring occurs
Solution Approach 1:
The contact electrode serves as a protective intermediary barrier between the assembly wiring and the corrosive fluid. It allows the self-assembly process to proceed with fluid exposure while preventing the fluid from directly contacting and corroding the assembly wiring, thus maintaining both process simplicity and wiring integrity
Data Source
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AI summary
The manufacturing method of the display device according to the embodiment includes a step of self-aligning the light emitting device inside the opening of the planarization layer overlapping the first assembly wiring and the second assembly wiring, a step of sequentially forming a conductive layer and an organic layer on a planarization layer and a light emitting device, a step of ashing the organic layer to remove the second part on the first part of the organic layer, and a step of forming a contact electrode by etching the conductive layer corresponding to the second part, wherein the contact electrode is in contact with the side of the first semiconductor layer below the light emitting device.