Grooved Rigid-Flex Circuit Board for High-Angle Bending
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Solution Overview
Problem
Rigid circuit boards have limited mechanical properties, resulting in a bendable angle of approximately 0° to 20°, beyond which they are damaged or broken, and cannot tolerate high bending stress.
Innovation Solution
A circuit board design featuring grooves extending along the long axis direction, filled with a flexible insulation film and insulation layers with a Young's modulus between 50 GPa and 80 GPa, allowing the grooves to deform and release bending stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the circuit board is made rigid to maintain structural stability, then the mechanical strength and hardness are improved, but the bending flexibility and bendable angle are limited to 0°-20°
Solution Approach 1:
The circuit board is segmented into rigid regions and flexible regions through groove structures. The grooves divide the rigid circuit board into multiple sections that can relatively move against each other, enabling bending flexibility while maintaining overall structural integrity and mechanical strength.
Solution Approach 2:
The circuit board employs a composite structure combining rigid materials (circuit board substrate) with flexible elements (groove regions). This composite design allows different parts to have different mechanical properties, achieving both structural stability and bending flexibility within the same component.
2Adaptability or versatility
If the bendable angle is increased beyond 20° to improve flexibility, then the adaptability is improved, but the circuit board is damaged or broken
Solution Approach 1:
By segmenting the circuit board into rigid and flexible regions, the grooves allow controlled deformation in specific areas while the rigid portions maintain structural integrity. This prevents damage even at large bending angles by localizing the stress to groove regions designed to accommodate deformation.
Solution Approach 2:
The groove structures act as pre-designed stress relief zones that cushion the bending stress before it can propagate through the entire circuit board. These grooves are positioned in advance to anticipate and absorb the mechanical stress during bending operations.
3Stability of the object's composition
If the rigid board structure is used to maintain hardness, then the manufacturing precision and structural stability are improved, but the bending strength cannot tolerate high stress
Solution Approach 1:
The circuit board is divided into rigid sections that maintain structural stability and flexible groove sections that provide bending strength. This segmentation allows the rigid portions to preserve structural integrity while the groove regions accommodate bending stresses without compromising overall stability.
Solution Approach 2:
Different regions of the circuit board are assigned different mechanical qualities: rigid regions provide structural stability and hardness, while groove regions provide flexibility and bending strength. This local differentiation of material properties resolves the contradiction between overall stability and local bending capability.
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 design increases the bending strength of the circuit board while maintaining hardness, enabling it to withstand greater bending angles without damage.
Implementation Method 1
the grooves are distributed in the bending part... when the bending part of the circuit board is under a bending state, the bending part of the circuit substrate is bent around the long axis direction that is as a bending axis, and a cross section of at least one of the grooves is deformed
Data Source
AI summary
A circuit board and a method of fabricating the same are provided. The circuit board has a flexible insulation film and a circuit substrate with a bending part. The circuit substrate is a rigid board and includes a plurality of grooves which are distributed in the bending part. Each of the grooves extends to two opposite ends of the circuit substrate in a direction of long axis, and an opening of one of the grooves is exposed to the surface of the circuit substrate. The flexible insulation layer is disposed on the surface of the circuit substrate and covers the opening of the groove, while the groove is not filled with the flexible insulation layer.