IC Chip Orientation on Bent Circuit Boards
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Solution Overview
Problem
Conventional circuit boards face challenges when integrated into curved or flexible display devices, as the bending of the board can cause physical stress leading to cracks in the IC chip and compromised bonding reliability.
Innovation Solution
A circuit board with a bending axis in a second direction intersecting the first direction, where the IC chip is mounted with its short side aligned to the bending direction of the board, minimizing stress and ensuring reliable bonding by aligning the IC chip's center axis with the board's bending axis, and incorporating flexible thin film board materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the IC chip is mounted with its long side aligned to the bending direction of the circuit board, then the bonding area is increased, but physical stress concentrates on the IC chip causing cracks and reduced reliability
Solution Approach 1:
The patent applies asymmetry by rotating the IC chip 90 degrees from the conventional mounting orientation. Instead of aligning the long side with the bending direction, the short side is aligned with the bending direction while the long side extends perpendicular to the bending axis. This asymmetric reorientation redistributes the stress distribution pattern, preventing stress concentration at the bonding interfaces while maintaining adequate bonding area.
Solution Approach 2:
The patent changes the mounting orientation parameter of the IC chip by 90 degrees. This parameter change transforms the stress distribution characteristics during board bending, shifting the stress from concentrated bonding interfaces to a more distributed pattern across the chip structure, thereby preventing cracks while maintaining bonding reliability.
2Stability of the object's composition
If a rigid circuit board is used, then structural stability is maintained, but the board cannot be bent to match curved display panels
Solution Approach 1:
The patent employs flexible thin film board materials to replace rigid circuit boards. The thin film construction allows the circuit board to be bent and conform to curved display panel surfaces while maintaining electrical connectivity and structural integrity. This enables the circuit board to adapt to various curved geometries without compromising stability.
Solution Approach 2:
The patent utilizes composite material structures for the circuit board, combining flexible substrates with conductive traces and bonding layers. This composite construction provides both the flexibility needed for curved surfaces and the structural stability required for reliable electrical connections and mechanical support.
3Reliability
If the IC chip is mounted perpendicular to the bending axis, then stress distribution is improved, but the routing of connection lines becomes more complex
Solution Approach 1:
The patent resolves the routing complexity by utilizing the perpendicular dimension relative to the bending axis. Connection lines are routed along the long side of the IC chip, which extends in the direction perpendicular to the bending axis. This dimensional approach allows lines to traverse the board in a direction that avoids high-stress regions while maintaining simple, straightforward routing paths.
Data Source
AI summary
A display device includes a display panel including a curved surface bent along a first direction, a circuit board coupled to the display panel, the circuit board being bent along the first direction in correspondence to the curved surface of the display panel, and an integrated circuit (IC) chip on the circuit board, a short side of the IC chip extending along the first direction.