Signal Pad Structure for Display Device Bonding
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Solution Overview
Problem
Display devices face bonding defects due to the limitations in the design of signal pads, which affect the electrical connectivity and reliability of the display panels.
Innovation Solution
The design incorporates a signal pad structure with a first and second conductive pattern layer, separated by insulation layers, where the second conductive pattern layer exposes portions of the insulation layers' surface and side surfaces, and the insulation layers are strategically arranged to reduce stress and enhance bonding, using a specific pattern and arrangement to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the signal pad uses a conventional design without exposed insulation layers, then the structure is simpler, but bonding defects occur and electrical connectivity is compromised
Solution Approach 1:
The signal pad is divided into multiple conductive pattern layers (first and second conductive pattern layers) separated by insulation layers. This segmentation allows the second conductive pattern layer to expose portions of the insulation layers, creating a stepped structure that distributes bonding stress and improves electrical connectivity while preventing bonding defects.
Solution Approach 2:
The signal pad structure transitions from a planar design to a three-dimensional configuration by exposing portions of the insulation layers between the conductive pattern layers. This dimensional change creates vertical steps that distribute mechanical stress during bonding and enhance electrical connection reliability.
2Reliability
If the insulation layers are completely covered by conductive pattern layers, then electrical connectivity is maximized, but stress concentration occurs leading to bonding defects
Solution Approach 1:
The insulation layers are exposed at specific locations between the conductive pattern layers, creating localized regions that serve dual purposes: maintaining electrical connectivity where covered while providing stress distribution pathways where exposed. This local differentiation resolves the contradiction between connectivity and bonding strength.
Solution Approach 2:
The exposed portions of the insulation layers act as intermediary elements between the conductive pattern layers and the bonding interface. These intermediary structures distribute mechanical stress during bonding processes while maintaining the electrical connectivity function of the conductive layers.
3Ease of manufacture
If the second conductive pattern layer fully covers the insulation layers, then manufacturing is simpler, but bonding defects increase due to stress concentration
Solution Approach 1:
The conductive pattern layers are segmented with intentional gaps where insulation layers are exposed. This segmentation, while adding a step to fabrication, prevents stress concentration during bonding and improves overall manufacturing precision by creating controlled stress distribution zones that prevent bonding defects.
Data Source
AI summary
A display device includes a first conductive pattern layer connected to a signal line, a second conductive pattern layer connected to the first conductive pattern layer, and an insulation pattern layer disposed between the signal line and the second conductive pattern layer and overlapping the second conductive pattern layer. The second conductive pattern layer exposes a portion of an upper surface and a side surface of the insulation pattern layer. The second conductive pattern layer includes first and second edge portions disposed on the upper surface of the insulation pattern layer and facing each other in a second direction intersecting a first direction. A distance between the first and second edge portions decreases as moving along the first direction in a first region of the upper surface of the insulation pattern layer, and increases as moving along the first direction in a second region of the upper surface.