Panel Pad Protrusions for Reliable ACF Bonding
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Solution Overview
Problem
Display devices face challenges with increased dead space near the display panel, leading to reduced image display area and unreliable electrical connections due to small panel pads and the risk of anisotropic conductive film (ACF) peeling and conductive balls flowing to external sides, causing electrical connections between adjacent pads.
Innovation Solution
The design enhances the contact area of panel pads by incorporating a concave center area and edge areas with protruding portions, preventing ACF peeling and conductive ball flow, and ensuring reliable electrical connections through increased contact area and strategic placement of organic layers and lower patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the dead space is reduced to increase the image display area, then the panel pads become smaller, but the electrical connection reliability deteriorates
Solution Approach 1:
The panel pad is divided into a center area and edge areas, with the center area having a different structure (protruding portions) than the edge areas. This segmentation allows the center area to provide enhanced contact for the anisotropic conductive film while the edge areas maintain the basic pad function, thereby improving electrical connection reliability even when the overall pad size is reduced.
Solution Approach 2:
The center area of the panel pad is given special local quality with protruding portions that extend toward the anisotropic conductive film. This local enhancement of contact area at the center region improves electrical connection reliability without requiring an increase in the overall pad size, thus resolving the contradiction between reduced dead space and maintained connection reliability.
2Area of stationary object
If the panel pad size is reduced to minimize dead space, then the dead space becomes smaller, but the contact area of the panel pad decreases
Solution Approach 1:
The protruding portions in the center area extend vertically toward the anisotropic conductive film, utilizing the third dimension (height/depth) to increase the effective contact area. This dimensional approach allows the pad to maintain sufficient contact area with the ACF even when the planar footprint is reduced to minimize dead space.
3Ease of manufacture
If the anisotropic conductive film is used for electrical connection, then the pad portion can be bonded, but the ACF may peel or conductive balls may flow to external sides
Solution Approach 1:
The protruding portions in the center area are designed to engage with the anisotropic conductive film before peeling or ball flow can occur. This preliminary structural engagement prevents the ACF from peeling by providing mechanical interlocking, and prevents conductive balls from flowing to external sides by containing them within the pad structure.
Data Source
AI summary
A display device includes: a substrate; an insulating layer on the substrate and including a first opening; a first panel pad on the substrate and the insulating layer; and an anisotropic conductive film on the first panel pad, and the first panel pad includes a center area located at a center of the first opening, and a first edge area and a second edge area arranged along a lateral side of the insulating layer and located on respective sides of the center area with respect to a first direction, and the anisotropic conductive film overlaps at least one of the center area, the first edge area, and the second edge area of the first panel pad.