Compact Rigid-Flexible PCB Manufacturing via Layer Segmentation
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Solution Overview
Problem
There is a need for smaller, more compact rigid-flexible printed circuit boards (PCBs) to accommodate the increasing miniaturization of electronic devices, as existing rigid-flexible PCBs are not adequately reduced in volume.
Innovation Solution
A manufacturing method for rigid-flexible PCBs involves pre-cut holes and unwanted portions on flexible PCBs, which are aligned and adhered using adhesive films and semi-curable glue pieces, then laminated with copper foil layers and etched to form trace layers, allowing for the creation of a compact multi-layer substrate that can be cut to form a smaller, more compact rigid-flexible PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional rigid-flexible PCB manufacturing methods are used, then the PCB can be manufactured with standard dimensions, but the volume and area of the PCB cannot be reduced sufficiently for compact electronic devices
Solution Approach 1:
The PCB is divided into multiple layers including flexible PCB layers and rigid substrate layers, with specific portions (unwanted portions) pre-defined for removal. This segmentation allows the final compact structure to be achieved by removing non-essential portions after assembly, resolving the contradiction between small volume and manufacturing ease.
Solution Approach 2:
Unwanted portions are pre-defined and pre-cut during the manufacturing process before final assembly. This preliminary action enables easier removal of excess material later, allowing the PCB to be manufactured with standard processes while achieving a compact final volume through selective material removal.
2Area of stationary object
If the area of rigid portions at the ends is reduced to make the PCB more compact, then the volume is reduced, but the structural stability and strength may be compromised
Solution Approach 1:
The PCB uses a composite structure combining flexible PCB materials with rigid substrate materials (such as FR-4). This composite construction allows reduction of rigid portion area while maintaining overall structural strength, as the flexible portions provide support and the rigid portions provide stability where needed.
Solution Approach 2:
The flexible PCB portions and rigid substrate portions are combined through lamination and adhesive bonding to form an integrated structure. This merging allows the rigid portions to be smaller while the flexible portions compensate for structural support, achieving compact area without sacrificing overall strength.
3Adaptability or versatility
If multiple layers are laminated together to create a multi-layer substrate, then the functional complexity increases, but the manufacturing process becomes more complex
Solution Approach 1:
The multi-layer structure is segmented into identical or similar flexible PCB layers and rigid substrate layers, with corresponding unwanted portions defined in each layer. This segmentation allows standardized manufacturing processes to be applied repeatedly, reducing the complexity of laminating multiple different layers while achieving high functional versatility.
Solution Approach 2:
The flexible PCB layers and rigid substrate layers are designed with universal characteristics, where each layer can serve multiple functions (structural support, electrical connectivity, mechanical flexibility). This universality simplifies the laminating process as the same manufacturing steps can be applied to all layers, increasing functional versatility without proportionally increasing process complexity.
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
This method enables the production of compact rigid-flexible PCBs by efficiently utilizing space, reducing the area of rigid portions at the ends, and facilitating easier peeling and removal of unwanted layers, resulting in a more compact electronic device component.
Implementation Method 1
aligned and adhered using adhesive films
Implementation Method 2
semi-curable glue pieces, then laminated with copper foil layers
Implementation Method 3
etched to form trace layers
Data Source
AI summary
A compact rigid-flexible board includes two flexible PCBs, two rigid substrates, a third trace layer and a fourth trace layer. The first flexible PCB includes a first depressing portion, a first exposed portion and a third depressing portion, and a separated second exposed portion. The second flexible PCB includes fourth and fifth depressing portions, and a second exposed portion. The first rigid substrate includes sixth, seventh, and eighth depressing portions. The second rigid substrate includes ninth and tenth depressing portions. The third trace layer, the sixth, first, fourth, and ninth depressing portions and the fourth trace layer are stacked in sequence. The third trace layer, the seven, second, fifth, and tenth depressing portions, and the fourth trace layer are stacked in sequence. The third trace layer and the eighth and third depressing portions are stacked in sequence.