Chip-on-Film Bonding Layout to Prevent Conductive Adhesive Shorts
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Solution Overview
Problem
Existing display devices face the technical challenge of short circuits between conductive adhesives due to the dense arrangement of terminals on chip on films (COFs), which is exacerbated by the need to minimize the size of the COF to reduce occupied capacity, leading to increased difficulty in preparing conductive adhesives and higher chances of short circuits.
Innovation Solution
The COF design includes a base with a first bonding portion and a second bonding portion, featuring concave and/or convex sub-portions and hollow portions, which increase the space for arranging bonding terminals, thereby increasing the distance between conductive adhesives and reducing the size of the COF, allowing for the same mask preparation of COFs and display panels, improving manufacturing efficiency and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the COF size is minimized to reduce occupied capacity, then the COF area is reduced, but the distance between conductive adhesives becomes smaller increasing short circuit risk
Solution Approach 1:
The patent transitions from a single linear bonding edge to multiple bonding portions distributed across different regions of the COF. By dividing the bonding terminals into first bonding portions and second bonding portions located at different positions and orientations, the design effectively utilizes two-dimensional space distribution, allowing adequate spacing between conductive adhesives even when the overall COF area is minimized.
2Area of stationary object
If terminals are arranged densely along edges to minimize COF size, then the COF area is reduced, but the distance between conductive adhesives becomes smaller making preparation more difficult
Solution Approach 1:
The bonding terminals are segmented into multiple distinct bonding portions (first bonding portions and second bonding portions) rather than being concentrated in a single dense arrangement. This segmentation distributes the terminals across different regions of the COF, creating sufficient working space for conductive adhesive application and improving manufacturing ease while maintaining compact COF dimensions.
3Device complexity
If terminals are arranged along edges of the COF, then the arrangement is simplified, but the distance between conductive adhesives becomes small increasing short circuit possibility
Solution Approach 1:
The patent extends the terminal arrangement from a single-edge linear configuration to a multi-region two-dimensional distribution pattern. The first bonding portions and second bonding portions are positioned at different locations and orientations, effectively utilizing spatial distribution to maintain adequate conductive adhesive spacing while preserving arrangement simplicity through modular positioning.
Data Source
AI summary
Display devices and chip on films are provided. The chip on film includes a display bonding area corresponding to bonding positions of a display panel, and includes a base and bonding terminals disposed on the base. In the display bonding area, the base includes first and second bonding portions, which are provided with the bonding terminals thereon. The first bonding portion has an outer contour and includes one part of outer edges of the base. The second bonding portion includes one or more first sub-portions including the other part of the outer edges of the base, and the first sub-portions are concave and/or convex relative to the outer contour; and/or the base further includes one or more hollow portions, the second bonding portion includes one or more second sub-portions, and each of the second sub-portions includes inner edges of the base surrounding one of the hollow portions.