Bendable Circuit Board With Segmented Rigid-Flexible Layers
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Solution Overview
Problem
Current bendable circuit boards, particularly rigid-flexible and semi-flexible boards, face challenges in manufacturing complexity and high costs due to the use of polyimide for bendable areas, and semi-flexible boards have low wiring density with single or double-layer conductive wiring.
Innovation Solution
A method involving a double-sided circuit substrate with alternating layers of flexible and rigid wiring boards, where flexible films are pressed between rigid wiring boards to create a bendable area with increased wiring density, using a layered structure that includes multiple conductive layers and adhesive resins, allowing for adjustable positioning and enhanced integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polyimide is used for bendable areas in rigid-flexible or flexible boards, then bendability is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The circuit board is divided into distinct rigid wiring boards and flexible films. The flexible film is segmented to cover specific bendable areas, allowing the board to be bent without affecting the entire structure. This segmentation enables simplified manufacturing by producing rigid and flexible components separately and then assembling them.
Solution Approach 2:
The invention uses a composite structure combining rigid wiring boards with flexible films. The flexible film acts as an insulating layer between rigid boards, creating a composite material system that provides both rigidity for wiring and flexibility for bending. This composite approach simplifies manufacturing compared to using polyimide throughout the entire board.
2Adaptability or versatility
If polyimide is used for bendable areas in rigid-flexible or flexible boards, then bendability is achieved, but manufacturing cost increases
Solution Approach 1:
The flexible film used in the invention is a simpler, more cost-effective alternative to polyimide. While polyimide provides excellent flexibility, the flexible film in this invention achieves sufficient bendability at a lower cost, making the overall manufacturing process more economical while maintaining the required flexibility for three-dimensional assembly.
3Ease of manufacture
If semi-flexible boards use single-layer or double-layer conductive wiring in bendable areas, then manufacturing is simplified, but wiring density decreases
Solution Approach 1:
The invention transitions from single-layer or double-layer conductive wiring to a multi-layer wiring structure. By adding more wiring layers within the bendable area, the wiring density is increased without compromising manufacturing simplicity. The flexible film accommodates these additional layers while maintaining flexibility.
4Quantity of substance
If multi-layer wiring structure is implemented in bendable areas, then wiring density increases, but structural complexity increases
Solution Approach 1:
The multi-layer wiring structure is implemented locally only in the bendable areas where high wiring density is required, rather than throughout the entire circuit board. The rigid wiring boards maintain their original simple structure in non-bendable areas, while only the flexible film regions incorporate the additional wiring layers. This localized approach increases wiring density without proportionally increasing overall structural complexity.
Data Source
AI summary
A bendable circuit board includes a first rigid wiring board, a first flexible film, a circuit substrate, a second rigid wiring board, a second flexible film, and a third rigid wiring board which are stacked in said order. The circuit substrate is a rigid double-sided circuit board. The first rigid wiring board defines a first window area in which the first flexible film is exposed, and the third rigid wiring board defines a second window area in which the second flexible film is exposed. The present disclosure further provides a method for manufacturing the bendable circuit board.