Flexible Printed Wiring Board Arc Layout for Stress Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional extra length absorbing portions in flexible printed wiring boards are large due to the use of external spring members, making them unsuitable for the reduced size and weight requirements of modern electronic devices, and they may break if simply miniaturized.
Innovation Solution
A flexible printed wiring board with an integrated extra length absorbing portion that includes a pattern connected portion, a coupling portion with a first linear wiring portion, a first arcuate wiring portion, and a second linear wiring portion, and a connecting terminal, where the first arcuate wiring portion has a central angle exceeding 180° and an inner diameter larger than the average spacing between the linear wiring portions, effectively reducing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional extra length absorbing portion with an external spring member is used, then stress concentration at the connecting portion is reduced, but the size and weight of the flexible printed wiring board increase
Solution Approach 1:
The patent merges the spring member with the flexible printed wiring board by integrating it into the insulating base film, forming a unified structure. This eliminates the need for separate external spring members while maintaining the stress absorption function, thereby reducing overall size and weight.
Solution Approach 2:
The patent uses a composite structure where the spring member is formed from the insulating base film material itself, creating a integrated composite component that combines structural support and elastic functionality in a single material system, reducing the need for additional components.
2Weight of moving object
If the conventional extra length absorbing portion is miniaturized, then size and weight are reduced, but the structure may break due to insufficient stress absorption capacity
Solution Approach 1:
The patent employs an inverted U-shape configuration for the spring member with specific curvature radius ratios (R1/R2 between 0.5-2.0) to optimize stress distribution. The curved geometry allows the structure to absorb stress through elastic deformation while maintaining strength, enabling miniaturization without compromising breakage resistance.
Solution Approach 2:
The patent optimizes geometric parameters of the spring member including curvature radius ratios (R1/R2 = 0.5-2.0), width ratios (W1/W2 = 0.5-2.0), and thickness ratios (T1/T2 = 0.5-2.0) to achieve the best balance between stress absorption capacity and structural strength, allowing miniaturized designs to maintain adequate strength.
3Ease of manufacture
If the spring member is integrated into the insulating base film, then manufacturing complexity is reduced, but the extra length absorbing capacity may be limited
Solution Approach 1:
The patent designs the spring member with optimized curvature and dimensional ratios that enable dynamic elastic deformation to absorb extra length. The inverted U-shape configuration with specific geometric ratios allows the integrated structure to provide sufficient absorption capacity while maintaining manufacturing simplicity through single-layer film integration.
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 provides a compact and reliable extra length absorbing portion that is resistant to breakage, ensuring reliable connection with external elements while maintaining the reduced size and weight requirements of modern electronic devices.
Implementation Method 1
the first arcuate wiring portion having a central angle exceeding 180°, the first arcuate wiring portion having an inner diameter larger than an average spacing between the first linear wiring portion and the second linear wiring portion
Implementation Method 2
the flexible printed wiring board and the other external element are interconnected using an extra length absorbing portion which can extend and contract as the distance between the flexible printed wiring board and the other external element changes
Data Source
AI summary
A flexible printed wiring board according to an aspect includes a base film, a conductive pattern disposed on one surface of the base film, and an extra length absorbing portion protruding from the base film and disposed in a direction of a plane, the extra length absorbing portion including a pattern connected portion connected to the conductive pattern, a coupling portion having a first linear wiring portion, a first arcuate wiring portion, and a second linear wiring portion coupled in this order continuously from the pattern connected portion, and a connecting terminal connected to the coupling portion, the pattern connected portion and the connecting terminal being opposite to each other in a direction in which the extra length absorbing portion protrudes.