What Is a Rigid-Flex PCB?
A Rigid-Flex PCB (Printed Circuit Board) is a type of printed circuit board. It has both rigid and flexible characteristics.
Printed circuit boards are components used to electrically connect electronic devices. They are responsible for transmitting signals and power, and allows wiring connections while fixing the position of each component. It is mounted as a built-in component of various electronic devices and is an indispensable component.
Features of Rigid-Flex PCB
Printed circuit boards are classified into two types: rigid and flexible.
Rigid boards are made of insulators, which are rigid and can withstand automated transport and facilitate component positioning. While they are strong, they are not flexible.
Flexible substrates are made of thin film and can be bent repeatedly. They can be mounted on components with weight limitations and are suitable for use in moving parts. The material itself is also an insulator.
A Rigid-Flex PCB is a composite board that combines a rigid circuit board and flexible circuit board. It was originally developed for use in space aircraft, where compactness was required. Prior to its development, multiple boards were connected by unstable wires, resulting in frequent defects and failures.
Principle of Rigid-Flex PCBs
The rigid part where components are mounted has a structure in which all layers of the flexible layer for three-dimensional wiring and the rigid layer for circuit formation are overlapped.
Although connectors are normally required to connect between the boards, the concept of connecting the outer and inner layers with through holes eliminates the height and weight of connectors.
The flexible part consists of only flexible layers. However, as the flexibility is impaired when the number of layers increases, the layers are separated by one or two layers. The total number of layers can be adjusted according to the desired application, and design proposals are generally made by each manufacturer.
Flexible substrates alone require careful work in mounting due to their thinness. The rigid board takes care of the base strength, making it possible to use existing mounting equipment.
The structure allows connection with a single lead wire, which has been confirmed to suppress noise generation. The omission of components has made it possible to realize smaller, lighter, and thinner devices, greatly expanding the range of applicable devices.
Uses of Rigid-Flex PCB
Rigid flexible substrates are available in various shapes, such as folding type, flying tail type, and book binder type, and can be used in a variety of ways depending on the conditions of the installation location.
Due to the wide range of substrate shape adjustment, rigid flexible substrates are widely used in devices that require compactness, light weight, and high reliability, such as home game consoles, cell phones, medical equipment, smart devices, storage devices, wearable devices, and communication base stations.
Other Information on Rigid-Flex PCB
1. Rigid-Flex PCB Issues
The process is more complicated than the manufacturing of rigid substrates or flexible substrates alone. Via positions need to be adjusted, and minute checks are required from the design stage.
The number of manufacturers is also limited, and the manufacturing cost is high.
2. Future Prospects
Recently, the printed circuit board market has been expanding due to improvements in communication technology and increased sales of electronic devices.
Standards that enable high-speed communications have a significant impact on infrastructure facilities, and higher-performance printed circuit boards are required. Furthermore, with the rise of AI technology, various industries intend to promote the use of IT. The diplomatic relations and circumstances of each country are also relevant, and the demand for these products is global.
Rigid flexible substrates are also being mounted in an increasing number of devices due to their characteristics, and a review of manufacturing efficiency is required.