Multi-Layer Pad Structure for High-Resolution Display Integration
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Solution Overview
Problem
As the resolution of display devices increases, the number of pads required in the pad portion increases, making it challenging to reduce the size of the pads while maintaining reliability, especially due to the increased number of conductive layers.
Innovation Solution
The display device incorporates a substrate with a display area and a non-display area, featuring pads with a specific layered structure, including a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer, where the second electrode layer is in contact with the first electrode layer through a contact hole, and the third, fourth, and fifth electrode layers cover the previous layers without insulating layers in between, enhancing the integration and reliability of the pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of pads is increased to support higher resolution, then the signal input/output capability is improved, but the pad size reduction becomes more difficult due to increased integration requirements
Solution Approach 1:
The pad structure transitions from a planar two-dimensional layout to a three-dimensional stacked configuration with multiple electrode layers (first through fifth electrode layers) vertically arranged. This dimensional change allows multiple signal pathways to be integrated within the same footprint area, enabling higher resolution support without proportionally increasing pad area.
Solution Approach 2:
Multiple electrode layers are nested vertically within each other, with the second electrode layer contacting the first through a contact hole, the third covering the second, the fourth covering the third, and the fifth disposed on insulating layers. This nested arrangement packs multiple functional elements into a compact vertical stack, reducing the horizontal space required for each pad while maintaining signal transmission capability.
2Quantity of substance
If the number of conductive layers is increased to accommodate more pads, then the integration degree is improved, but the manufacturing complexity and reliability become more difficult to maintain
Solution Approach 1:
Insulating layers are selectively removed or omitted at specific interfaces between electrode layers (between second and third, and between third and fourth electrode layers) to create direct contact regions. This extraction of insulating material reduces the total number of layers that could fail, simplifies the structure, and improves reliability by eliminating potential failure points while maintaining the necessary electrical connections.
Solution Approach 2:
The contact hole serves as an intermediary structure that enables electrical contact between the first and second electrode layers through the insulating layer. This controlled intermediary approach allows selective insulation and conduction, maintaining reliability by providing defined pathways for signal transmission while managing the complexity of multiple conductive layers.
3Area of stationary object
If the pad size is reduced to increase integration, then the area efficiency is improved, but the reliability of each individual pad may deteriorate
Solution Approach 1:
The pad structure utilizes vertical stacking of multiple electrode layers to compensate for reduced horizontal pad area. By distributing pad functions across multiple vertical layers (first through fifth electrode layers), the design maintains sufficient total conductive material and signal transmission capability even when each individual pad's footprint is reduced for better integration.
Data Source
AI summary
Provided is a display device which includes a substrate having a display area and a non-display area, and a plurality of pads disposed in the non-display area. Each of the pads includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer which are sequentially disposed on the substrate, and the second electrode layer is in contact with the first electrode layer through a contact hole formed in one or more insulating layers.