Dummy Pad Leveling for Display Panel Bonding Reliability
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Solution Overview
Problem
The bonding reliability between the pads of a display panel and the printed circuit film is degraded due to steps occurring between connected and unconnected pads, affecting the overall performance of display devices.
Innovation Solution
Incorporating a dummy pad between the first pad and a group of second pads, with specific surface level configurations and conductive layer structures, to enhance the bonding reliability by optimizing the contact resistance and spacing between pads and leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pads are arranged with different heights for functional differentiation, then signal transmission functionality is improved, but bonding reliability between pads and printed circuit film deteriorates
Solution Approach 1:
The patent introduces a dummy pad that extends in the thickness direction (vertical dimension) to connect pads at different height levels. This dimensional transition allows signal transmission between different pad levels while maintaining planar bonding surfaces for reliable connection to the printed circuit film, thus resolving the contradiction between functional differentiation and bonding reliability.
2Adaptability or versatility
If multiple conductive layers are stacked to achieve different pad heights, then electrical functionality is improved, but manufacturing complexity increases
Solution Approach 1:
The dummy pad structure serves multiple functions simultaneously: it acts as a conductive connection between different height levels, provides a bonding surface for the printed circuit film, and maintains electrical isolation where needed. This multi-functionality reduces the need for separate structures, thereby managing manufacturing complexity while achieving electrical functionality.
3Reliability
If dummy pad is added to resolve bonding issues, then bonding reliability is improved, but device complexity increases
Solution Approach 1:
The dummy pad is integrated with the existing conductive layers and pad structures rather than being a completely separate component. It merges the functions of electrical connection, mechanical support, and bonding surface provision into a single unified structure, thereby improving bonding reliability while minimizing the increase in device complexity.
Data Source
AI summary
A display device includes a display area; a pad area including a first pad for supplying a data signal to the display area, second pads for transmitting a DC signal, and a dummy pad, wherein each of the first pad, the second pads, and the dummy pad has a surface as a top face thereof, wherein each of the surface of the first pad, the surface of the second pads, and the surface of the dummy pad has a corresponding vertical level in a thickness direction of the display device, wherein the vertical level of the surface of each of the second pads is higher than the vertical level of the surface of the first pad, wherein the vertical level of the surface of the dummy pad is lower than or equal to the vertical level of the surface of the first pad.