Reinforced Flexible Circuit Board Joint to Prevent Boundary Cracking
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Solution Overview
Problem
The connection structure between the flexible circuit board and the main circuit board using the hot-bar method lacks rigidity, leading to potential bending, cracks, or tearing at the boundary due to its two-dimensional nature.
Innovation Solution
A flexible circuit board design incorporating a reinforcing member between first and second layers, oriented in opposite directions, with overlapping portions and connection holes, to enhance rigidity and prevent cracking or tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-dimensional connection structure using hot-bar method is used, then the bonding process is simple, but the rigidity of the connection structure is insufficient leading to bending and cracks
Solution Approach 1:
The patent transitions from a two-dimensional connection structure to a three-dimensional structure by adding a reinforcing member that extends in the thickness direction. This reinforcing member includes a first portion in the first connection part and a second portion in the second connection part, creating a three-dimensional configuration that enhances rigidity while maintaining bonding simplicity.
Solution Approach 2:
The connection structure combines multiple materials: the flexible circuit board substrate, the bonding material (solder or conductive adhesive), and the reinforcing member (rigid or semi-rigid material). This composite structure leverages the advantages of each material to achieve both ease of manufacture and enhanced rigidity.
2Strength
If the connection structure is made more rigid, then cracking and tearing are prevented, but the flexibility of the circuit board is reduced
Solution Approach 1:
The reinforcing member is strategically positioned only in the connection parts where rigidity is needed, while the flexible circuit board maintains its flexibility in other areas. The first and second portions of the reinforcing member are located specifically in the connection parts to provide localized reinforcement without compromising overall flexibility.
Solution Approach 2:
The reinforcing member is divided into multiple portions (first portion in the first connection part, second portion in the second connection part), allowing independent optimization of each segment. This segmentation enables the structure to be rigid where needed and flexible where required.
3Strength
If a reinforcing member is added to enhance rigidity, then structural integrity is improved, but the device complexity increases
Solution Approach 1:
The reinforcing member is integrated with the connection parts through the bonding material, merging the reinforcement function with the existing connection structure. The first and second portions are bonded to the flexible circuit board, combining multiple functions into a unified structure that reduces overall complexity.
Solution Approach 2:
The reinforcing member serves multiple functions: it provides rigidity to prevent cracking, maintains structural integrity during bonding, and can be configured to accommodate connection holes. This multi-functionality reduces the need for separate components, thereby reducing device complexity.
Data Source
AI summary
An electronic device is provided. The electronic device includes a housing, a main circuit board arranged inside the housing, and at least one flexible circuit board electrically connected to the main circuit board, wherein the flexible circuit board includes a flexible circuit part, and a joining part arranged on one end of the flexible circuit part and connected to the main circuit board. A first joining part includes a first layer oriented a first direction and having at least one first connection hole, a second layer oriented in a second direction opposite to the first direction and has at least one second connection hole, and a reinforcement member which is arranged between the first and the second layer and is connected to the flexible circuit part while being arranged such that at least a portion thereof overlaps with the one end part of the flexible circuit part.