Micro LED Electrode Layout to Prevent Missing-Pixel Short Circuits
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Solution Overview
Problem
Micro LED displays are prone to electrical short circuits due to missing micro LEDs, leading to reliability issues and increased power consumption.
Innovation Solution
A first optical layer encloses micro LEDs, exposing unpopulated solder pads, and a second electrode is applied selectively over the optical layer, with redundant micro LEDs in each sub-pixel to ensure functionality, along with a flexible layer configuration and shared electrode structure to reduce mechanical stress and circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a micro LED is missing from a sub-pixel, then the display structure remains intact, but electrical short circuits occur between electrodes and solder pads
Solution Approach 1:
The patent extracts the harmful conductive material (second electrode) from areas where it would cause short circuits. Specifically, the second electrode is selectively removed from sub-pixels where micro LEDs are missing, preventing electrical short circuits between the second electrode and solder pads while maintaining the structural integrity of the display apparatus.
Solution Approach 2:
The patent performs preliminary inspection and selective removal of the second electrode before final assembly. By identifying sub-pixels with missing micro LEDs and removing the second electrode from those specific areas in advance, the patent prevents short circuit defects from occurring in the first place, rather than dealing with them after assembly.
2Ease of manufacture
If the second electrode is applied over all sub-pixels, then manufacturing process is simplified, but short circuits occur in sub-pixels with missing micro LEDs
Solution Approach 1:
The patent applies local quality by making the second electrode's presence or absence location-dependent. Instead of uniformly applying the second electrode across all sub-pixels, the patent selectively applies it only to sub-pixels that contain micro LEDs, while omitting it from sub-pixels with missing micro LEDs. This local differentiation resolves the contradiction by maintaining manufacturing simplicity while preventing short circuits.
Solution Approach 2:
The patent introduces dynamic decision-making into the electrode application process. Rather than a static, uniform application method, the patent employs a dynamic approach where the application of the second electrode is conditional based on the presence or absence of micro LEDs in each sub-pixel, allowing the process to adapt to actual component placement outcomes.
3Reliability
If redundant micro LEDs are included in each sub-pixel, then functionality is ensured through selection during inspection, but device complexity increases
Solution Approach 1:
The patent implements beforehand cushioning by including redundant micro LEDs in each sub-pixel as a preventive measure. This redundancy acts as a buffer against potential failures or missing components, ensuring that functional display elements are available even if some micro LEDs are missing or defective, and allowing selection of functioning elements during inspection.
Data Source
AI summary
A display apparatus is provided in the present disclosure. The display apparatus includes a substrate, a pixel driving circuit disposed on the substrate, a bank disposed on the pixel driving circuit, a first electrode which is disposed on the bank and is connected to the pixel driving circuit, a plurality of solder patterns disposed on the plurality of first electrodes, a micro LED disposed on one solder pattern, among the plurality of solder patterns, a first optical layer which is disposed so as to enclose the micro LED and exposes another solder pattern, among the plurality of solder patterns, and a second electrode which is disposed on the micro LED and the first optical layer and exposes the another solder pattern. Accordingly, a short-circuit defect between the solder pattern and the second electrode may be minimized or reduced.