Chip Packaging Structure for Narrow Border Displays
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Solution Overview
Problem
Current chip-on-film technologies face challenges in achieving narrow borders for large-sized display devices, particularly in high-resolution applications, due to limitations in pitch and arrangement of input and output pads, which result in increased costs and complexity.
Innovation Solution
A chip packaging structure that includes a flexible substrate with input and output pads arranged in a mirror-symmetrical configuration on opposite sides, connected through traces, and a rigid substrate with a chip bonded to both the drive printed circuit board and display panel, allowing for reduced border width and simplified trace design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional chip-on-film packaging is used, then the display device can be manufactured with conventional pad arrangements, but the border width cannot be reduced further and manufacturing precision deteriorates due to pitch limitations
Solution Approach 1:
The patent applies asymmetry by arranging input pads and output pads in mirror-symmetrical configurations on opposite sides of the flexible substrate, rather than using traditional symmetric arrangements. This asymmetric layout allows for optimized signal routing and enables narrower borders while maintaining manufacturing precision through balanced impedance control.
Solution Approach 2:
The patent transitions from conventional two-dimensional pad arrangements to a three-dimensional configuration by stacking input and output pads on opposite sides of the flexible substrate. This dimensional change allows signals to route through the substrate thickness, reducing the horizontal space required and enabling narrower display borders while maintaining pitch requirements.
2Length of moving object
If pad pitch is reduced to achieve narrow borders, then border width decreases, but manufacturing complexity and costs increase
Solution Approach 1:
The patent segments the pad arrangement into distinct input pad groups and output pad groups located on opposite sides of the flexible substrate. This segmentation allows each group to be independently optimized with standard pitch dimensions, avoiding the need for reduced pitch while achieving narrow borders through the spatial separation enabled by the mirror-symmetrical configuration.
3Ease of manufacture
If mirror-symmetrical pad arrangement is used, then trace design is simplified and impedance is optimized, but pad layout complexity increases
Solution Approach 1:
The patent uses mirror-symmetry (a form of controlled asymmetry) where input pads on one side correspond to output pads on the opposite side in a mirrored arrangement. This creates a predictable pattern that simplifies trace routing and impedance matching, as each trace follows a symmetric path through the substrate, while the overall layout remains systematic rather than chaotic.
Data Source
AI summary
The present disclosure provides a chip packaging structure including at least one chip packaging unit. The chip packaging unit includes a flexible substrate and a rigid substrate. The flexible substrate includes a first flexible substrate body, and a plurality of input pads and a plurality of output pads arranged on the first flexible substrate body, wherein the input pads and the output pads are connected in one-to-one correspondence. The rigid substrate includes a rigid substrate body and a chip arranged on the rigid substrate body, wherein the rigid substrate is bonded to a drive printed circuit board of a display device. Two opposite sides of the flexible substrate are respectively bonded to the rigid substrate and a display panel of the display device. The plurality of input pads are electrically connected to the chip, and the plurality of output pads are configured to transmit signals to the display panel.