Display Device Pad Electrode Alignment via Protective Layer Openings
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Solution Overview
Problem
High alignment tolerance between pad electrodes and lead electrodes in display devices leads to screen driving failures, particularly at high resolutions, where precise alignment is crucial for preventing failures.
Innovation Solution
A display device design that includes a first base portion with a display area and a non-display area, featuring pad electrodes with a protective layer and a printed circuit film with lead electrodes, where panel alignment marks and insulating portions are strategically positioned to reduce alignment errors by exposing upper surfaces of pad electrodes and ensuring precise electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pad electrodes is increased to support high resolution, then the resolution capability is improved, but the alignment precision between pad electrodes and lead electrodes deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining alignment marks on the panel before the bonding process. These alignment marks serve as reference points that guide the positioning of lead electrodes, ensuring precise alignment even when the number of pad electrodes is increased for high resolution displays. The alignment marks are positioned in advance to compensate for potential misalignment issues.
Solution Approach 2:
The patent introduces alignment marks as an intermediary element between the pad electrodes and lead electrodes. These alignment marks act as a mediator that facilitates precise alignment by providing visual or mechanical references during the bonding process, thereby maintaining alignment precision despite the increased complexity from having more electrodes.
2Reliability
If alignment tolerance is reduced to prevent screen driving failures, then the reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent reduces manufacturing complexity by performing alignment mark positioning in advance, during the panel fabrication process. This preliminary action ensures that alignment references are already in place before the bonding process begins, thereby reducing the need for complex real-time alignment mechanisms and simplifying the overall manufacturing process while maintaining high reliability.
Solution Approach 2:
The patent uses alignment marks that can be replicated or copied across the panel surface. These marks serve as standardized reference patterns that can be consistently reproduced, simplifying the alignment process by providing uniform reference points throughout the display area, thereby reducing manufacturing complexity while ensuring consistent alignment quality.
3Manufacturing precision
If pad electrodes are exposed to improve alignment accuracy, then the alignment precision is improved, but the protection of pad electrodes deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the protective layer into different regions: areas with open portions where pad electrodes are exposed for alignment, and areas where the protective layer remains intact for protection. This segmented approach allows simultaneous achievement of alignment accuracy through exposure and protection through coverage in other areas.
Solution Approach 2:
The patent implements local quality by providing differential treatment to different regions of the protective layer. Over certain pad electrodes, the protective layer is removed to expose the electrode surface for precise alignment. Over other pad electrodes, the protective layer is maintained to provide protection. This localized approach allows the structure to optimize for both alignment accuracy and protection where needed.
Data Source
AI summary
The display device comprises a first base portion including display and non-display areas and a pad area, and a printed circuit film attached to the pad area of the first base portion, wherein pad electrodes on the first base portion and a first panel alignment mark on one side of the plurality of pad electrodes are disposed in the pad area, a first protective layer is on the pad electrodes, and a first open portion that exposes a portion of an upper surface of each pad electrode is defined in the protective layer, the printed circuit film includes a third base portion and lead electrodes on a lower surface of the third base portion and connected to the pad electrodes, and the first panel alignment mark includes a first panel alignment metal portion and a second open portion and surrounded by the first panel alignment metal portion on a plane.