Display Apparatus Contact Holes Current Density Optimization
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Solution Overview
Problem
Existing display apparatus designs with contact holes arranged in a single file or multiple files experience increased parasitic resistances and power losses due to current flow issues between high-resistant TCO electrodes and low-resistant wiring, making it difficult to achieve a narrow frame without unnecessary increases in contact hole opening areas.
Innovation Solution
The design includes a substrate with a thin-film transistor and planarization film, featuring first and second contact holes with different opening areas and distances from the display region, where the second contact hole has a smaller opening area and longer distance from the display region than the first, ensuring equalized current densities and reduced power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If contact holes are arranged in single file from TCO electrode to low-resistant wiring, then the opening area of each contact hole is reduced, but parasitic resistances between contact holes are increased and power losses occur
Solution Approach 1:
The patent applies local quality by differentiating the opening areas of contact holes based on their position relative to the display region. Contact holes closer to the display region have larger opening areas to handle higher current densities, while those farther away have smaller opening areas. This localized differentiation optimizes current distribution and reduces parasitic resistance without unnecessarily increasing overall contact hole area.
2Loss of energy
If the distance between display region and contact holes is increased, then currents flowing into contact holes are decreased, but opening areas are unnecessarily increased making narrow frame achievement difficult
Solution Approach 1:
The patent applies parameter changes by systematically varying the opening area parameter of contact holes based on their distance parameter from the display region. Contact holes at different positions have different opening area parameters optimized for their specific current load, rather than using a uniform opening area for all contact holes. This parameter optimization enables narrower frames while maintaining electrical performance.
3Reliability
If contact holes are arranged in multiple files, then currents are distributed, but parasitic resistances are increased and frame width is increased
Solution Approach 1:
The patent applies segmentation by dividing the contact hole array into multiple files with different opening area characteristics. Each file is segmented to handle specific current paths, with opening areas optimized for their respective positions. This segmentation approach distributes current effectively while controlling overall frame width through selective opening area reduction in appropriate segments.
Data Source
AI summary
In a display apparatus, a thin film transistor, a planarization film, and at least two light-emitting devices are provided on a substrate, and the light-emitting device at least includes a light-emitting layer and first and second electrodes. At least two first contact holes and at least two second contact holes are provided in the planarization film at a part outside a display region and connect the first electrode to ground wiring and/or power wiring with a resistance lower than that of the first electrode, the distance between the second contact hole and the display region is longer than that between the first contact hole and the display region, and the opening area of the second contact hole is smaller than that of the first contact hole.