Display Pad Electrode Layout Using Dummy Electrodes Against Shorts
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Solution Overview
Problem
Short-circuit failures often occur between electrodes adjacent to the pad area in display devices, particularly due to differences in diffraction degrees during the photomask process, leading to misalignment and potential electrical connections.
Innovation Solution
Incorporation of dummy electrodes in the non-display area adjacent to the pad area, which are not connected to the display area, helps maintain consistent exposure during the photomask process, ensuring adequate separation and preventing short-circuit failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photomask process is performed without dummy electrodes, then manufacturing process is simpler, but electrode misalignment and short-circuit failures occur due to diffraction degree differences
Solution Approach 1:
Dummy electrodes are formed in advance in the non-display area before the actual electrode formation. These dummy electrodes serve as reference structures that maintain consistent diffraction patterns during the photomask process, ensuring proper alignment of the actual electrodes without causing short-circuits.
Solution Approach 2:
The dummy electrodes act as intermediary reference structures between the photomask pattern and the actual electrodes. They mediate the alignment process by providing consistent diffraction references that guide the formation of properly spaced electrodes, preventing direct misalignment between adjacent electrodes.
2Manufacturing precision
If dummy electrodes are added to prevent short-circuits, then electrode alignment reliability improves, but device structure becomes more complex
Solution Approach 1:
Dummy electrodes are placed only in the non-display area where they are needed for alignment reference, while the display area maintains its original simple structure. This localized addition provides manufacturing precision where required without unnecessarily complicating the entire device structure.
Solution Approach 2:
The dummy electrodes are formed as preliminary reference structures during the manufacturing process, establishing the correct spacing pattern before the actual electrodes are formed. This preliminary action ensures precise electrode spacing without requiring complex real-time control during electrode formation.
3Reliability
If dummy electrodes are used in the photomask process, then short-circuit failures are prevented, but manufacturing process steps increase
Solution Approach 1:
The formation of dummy electrodes is merged with the existing electrode formation process. The same conductive material layers and patterning steps are used for both dummy electrodes and actual electrodes, so the dummy electrodes are created as part of the normal manufacturing flow without requiring entirely separate process steps.
Solution Approach 2:
The dummy electrodes are created as copies of the actual electrode structures using the same photomask patterns and material deposition processes. This copying approach allows the dummy electrodes to be formed with identical properties to the real electrodes, ensuring reliable alignment references while using the existing manufacturing capabilities without modification.
Data Source
AI summary
A display device comprises a substrate including a display area and a pad area adjacent to the display area; at least one pad electrode disposed on the substrate in the pad area and connected to the display area; and at least one dummy electrode overlapping the at least one pad electrode and not connected to the display area.