Chip-on Film Coating Layer Guides Anisotropic Conductive Film
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Solution Overview
Problem
The existing process for attaching a chip-on film to a pad portion of an OLED display using anisotropic conductive film often results in overflow, making it difficult to separate the support substrate from the polyimide substrate, leading to defective drives and reduced production yield.
Innovation Solution
A chip-on film with a coating layer made of the same material as the anisotropic conductive film is used, which guides the conductive film to spread and prevent overflow, ensuring reliable separation and improved production processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anisotropic conductive film is used to attach the chip-on film to the pad portion, then electrical connection is achieved, but the conductive film overflows from the substrate making separation difficult
Solution Approach 1:
The invention divides the chip-on film structure into distinct functional regions: a coating layer region and a film pad portion region. The coating layer is positioned at specific areas (edges and/or corners) while the film pad portion remains exposed. This segmentation allows the anisotropic conductive film to be contained within defined boundaries, preventing overflow while maintaining electrical connection functionality.
Solution Approach 2:
The coating layer is pre-formed on the chip-on film before the TAB process. This preliminary action creates a material boundary that guides the anisotropic conductive film during attachment, preventing it from overflowing onto the substrate. The coating layer acts as a pre-established barrier that controls conductive film spread during the subsequent bonding process.
2Reliability
If the anisotropic conductive film is applied with sufficient pressure for proper bonding, then electrical connection is improved, but overflow increases making separation more difficult
Solution Approach 1:
The chip-on film structure implements local quality by applying the coating layer only at specific locations (edges and/or corners) rather than uniformly across the entire surface. This localized modification creates specific interaction zones that control anisotropic conductive film behavior at critical areas while leaving other areas (film pad portions) unchanged for electrical connection functions.
Solution Approach 2:
The coating layer serves as an intermediary element between the chip-on film and the anisotropic conductive film. It mediates the interaction by providing a material interface that guides and contains the conductive film during the TAB process, preventing overflow while allowing proper bonding to occur at the film pad portions.
3Stability of the object's composition
If the support substrate and polyimide substrate are attached by the anisotropic conductive film, then structural stability is achieved, but separation becomes difficult
Solution Approach 1:
The invention segments the substrate assembly into distinct functional zones: areas where the anisotropic conductive film is contained (by the coating layer) and areas where it is not. This segmentation ensures that the conductive film provides structural stability where needed while preventing it from creating unwanted adhesion between the support substrate and polyimide substrate, enabling easy separation.
Solution Approach 2:
The invention extracts or removes the coating layer from certain areas (where film pad portions are exposed) to prevent the anisotropic conductive film from creating excessive adhesion between substrates. By selectively removing the coating layer in these areas, the patent enables easy substrate separation while maintaining stability where the coating layer is present.
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
The solution effectively prevents anisotropic conductive film overflow, ensuring reliable substrate separation and enhancing production yield by improving the TAB process, thus preventing defective drives and improving display device quality.
Implementation Method 1
a coating layer which guides the anisotropic conductive film to spread and prevents overflow
Data Source
AI summary
A chip-on film and a display device including the same are disclosed. The chip-on film includes a first base film, a second base film positioned on the first base film, a film pad portion positioned on at least one side of the second base film and exposed to the outside of the first base film, and a coating layer positioned on one surface of the first base film.