Vertical LED Common Cathode Structure for Short-Circuit Isolation
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Solution Overview
Problem
Small-size flip-chip LED chips are prone to short circuits and reliability issues due to close spacing of electrodes in the same plane, which complicates manufacturing and reduces the efficiency and reliability of MiniLED Displays with high pixel density.
Innovation Solution
A common cathode electrode structure for vertical LED pixel packages, utilizing a package carrier, conductive column, insulating isolation support, and common cathode metal thin film layer to electrically connect N electrodes to a common cathode and P electrodes to anodes without wire bonding, ensuring electrodes are in separate planes and reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flip-chip LED chips with bottom adhesion mode are used to eliminate wire bonding, then manufacturing efficiency is improved, but short circuit risk increases due to close spacing of electrodes in the same plane
Solution Approach 1:
The patent transitions from a two-dimensional planar electrode arrangement (both electrodes at the bottom) to a three-dimensional spatial separation (one electrode at bottom, one at top). The N electrode remains at the bottom for adhesion while the P electrode is positioned at the top, utilizing the vertical dimension to achieve electrode separation and eliminate short circuit risks while maintaining efficient manufacturing.
Solution Approach 2:
The patent segments the electrode arrangement into distinct spatial zones: the N electrode is located at the bottom surface for conductive adhesion to the package carrier, while the P electrode is positioned at the top surface. This segmentation separates functions (adhesion vs. electrical connection) into different spatial locations, eliminating the short circuit problem inherent in co-planar arrangements.
2Manufacturing precision
If electrode spacing is reduced to achieve smaller pixel pitch, then display resolution is improved, but manufacturing precision requirements increase due to diffusion of conductive substances
Solution Approach 1:
By moving the P electrode to the top surface and the N electrode to the bottom surface, the patent creates maximum spatial separation between electrodes. This vertical separation eliminates the need for tight lateral spacing, allowing smaller pixel pitches without increasing the risk of conductive substance diffusion causing short circuits.
Data Source
AI summary
A common cathode electrode structure for vertical LED pixel package, includes a package carrier, vertical LED chips, a conductive column, an insulating isolation support, and a common cathode metal thin film layer. The vertical LED chips are arranged above package carrier, the package carrier includes anodes and a common cathode penetrating therethrough to be external connection point. The anodes are respectively corresponded and electrically connected to P electrodes of the vertical LED chips, and the conductive column is electrically connected to common cathode and N electrodes of vertical LED chips. The common cathode metal thin-film layer is formed on vertical LED chips, conductive column and insulating isolation support to electrically conduct the conductive column and the N electrodes. The anodes and common cathode are in the same plane, which can meet the requirements for embodying SMT for small-spacing LED display module.