Display Pad Structure With Step Compensation for Delamination Control
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Solution Overview
Problem
Display devices face issues with step differences between pad electrodes and non-active areas, leading to delamination defects, visibility issues due to gaps between the optical film and side insulating layer, and short circuit defects from migration phenomena, which increase manufacturing costs and reduce reliability.
Innovation Solution
The implementation of step compensation layers in non-active areas between pad electrodes and side lines, formed using a pad printing method with fast-drying black ink, to flatten the surface and minimize step differences, thereby reducing gaps and enhancing contact areas, and preventing short circuit defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pad electrodes are formed on the non-active area, then electrical connection is achieved, but step differences cause delamination defects and visibility issues
Solution Approach 1:
A step compensation layer is introduced as an intermediary element between the pad electrode and the optical film. This layer fills the step difference created by the pad electrode structure, providing a flat surface that prevents delamination and improves visibility. The step compensation layer acts as a mediator that resolves the conflict between maintaining electrical connection and eliminating surface irregularities.
2Reliability
If step compensation layers are formed to reduce step differences, then delamination defects are prevented, but manufacturing process complexity increases
Solution Approach 1:
The step compensation layer formation process is merged with the existing pad printing process used for creating the black matrix and other patterns. By integrating the step compensation layer formation into the same pad printing step, the manufacturing process complexity is minimized while still achieving the desired step difference compensation. This combining approach avoids adding separate processing steps.
3Manufacturing precision
If multiple printing processes are used to form step compensation layers, then surface flatness is improved, but manufacturing cost increases
Solution Approach 1:
The pad printing process is designed to perform multiple functions simultaneously: it creates the black matrix pattern, forms the step compensation layer, and provides surface flatness correction. This multi-functional approach eliminates the need for separate printing processes, reducing manufacturing cost while achieving the required surface flatness for preventing delamination and improving visibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces delamination defects, improves visibility by eliminating gaps, and minimizes short circuit risks, while simplifying the manufacturing process and lowering costs by using a single pad printing process for forming step compensation layers.
Implementation Method 1
forming step compensation layers with a minimal pad printing process
Data Source
AI summary
A display device can include a first substrate having an active area and a non-active area, where the non-active area includes a plurality of first areas spaced apart from each other and a plurality of second areas disposed between the plurality of first areas. The display device can further include a plurality of first pad electrodes disposed on the plurality of first areas, a plurality of side lines disposed on the plurality of first pad electrodes, and a plurality of step compensation layers disposed in the plurality of second areas. By additionally forming the step compensation layers in the second areas, it is possible to compensate for step differences between the plurality of first areas and the plurality of second areas.