What are the types of FPCBs according to structure?

Flexible Printed Circuit Boards (FPCBs) are like different kinds of bridges connecting electronic components. Some are like simple wooden planks, straightforward and lightweight, while others resemble multi-layered suspension bridges, handling more complex connections. Some can bend like rope bridges, adapting to movement, while others combine flexibility and rigidity, like a drawbridge that moves but stays strong. The choice of FPCB depends on the structural needs of the device.

Single-sided FPC

Single-Sided FPCBs

Single-sided FPCB is one of the most basic and simple structures. In a single-sided Flex PCB, the circuit is only present on the substrate on one side, while the other side is usually bare or covered with a protective layer. Single-sided FPCB is suitable for simple circuit routing needs, with a lower cost and a simpler manufacturing process.

Key Features:

Lightweight and cost-effective

Simple structure with one conductive layer

Suitable for low-complexity applications

Common Applications:

LED lighting strips

Sensors

Consumer electronics like printers and calculators

Double-sided FPC

Double-Sided FPCB

The double-sided FPC structure has circuits on both sides. More complex circuit layouts and connections are achieved by adding circuits on both sides. Double-sided flex PCBs typically have higher densities and more connectivity options, making them suitable for more complex electronic devices such as mobile phones, tablets, etc. Since double-sided FPCBs can accommodate more circuit components in the same space, more functions and higher performance can be realized.

Key Features:

Conductive layers on both sides

Increased circuit density

Improved electrical performance

Common Applications:

Automotive dashboards

Industrial control systems

Wearable electronics

Flex-rigid PCB

Rigid-flex PCB

Flex-rigid PCB combines the characteristics of flexible PCB and rigid PCB. They typically consist of flexible sections and rigid sections interconnected by reliable connection methods. Flexible sections are often used for parts requiring bending and folding, while rigid sections are used for support and stability. This structure is suitable for applications that require both flexibility and rigidity, such as foldable smartphones, camera modules, etc.

Key Features:

Combination of rigid and flexible sections

Reduced need for connectors and interconnections

Improved reliability and durability

Common Applications:

Military and aerospace electronics

High-end medical devices

Foldable smartphones and wearable tech

Multilayers FPC

Multilayers Flex PCB

Multilayer FPCB structures consist of multiple layers stacked together. These layers are interconnected through inner layer connections and alternate between flexible substrates. Multilayer flex PCBs are typically used in applications that require higher signal density and complex layouts, such as computer motherboards, industrial control systems, etc. Because multilayer printed circuit boards can accommodate more circuit layers in a smaller space, they enable designs with more complex functions and higher performance.

Key Features:

Multiple conductive layers

High-density circuit design

Enhanced performance and reliability

Common Applications:

Aerospace and military equipment

Medical imaging devices

Smartphones and tablets

Dual Access (Bare back)

Split & Dual Access (Bare Back)

Split flex PCB structures allow the creation of multiple independent areas on the FPC board, each of which can be accessed and connected to circuits. This structure is used in applications that require the separation of different functions or modules to improve system flexibility and maintainability. Split flex PCBs are often combined with dual access (bareback), allowing direct access to circuits on the back of the FPC, simplifying the connection and maintenance processes.

Key Features:

Variable copper thickness

Enhanced durability and mechanical support

Suitable for high-stress environments

Common Applications:

High-durability electronic connectors

Custom-designed electronic components

Single-Layer Flex with Stiffener

This type of FPCB consists of a single-layer flexible circuit with an additional stiffener for structural support. The stiffener helps in reinforcing specific areas, making it easier to mount components.

Key Features:

Added stiffener for structural integrity

Low-cost and easy to manufacture

Ideal for applications requiring localized rigidity

Common Applications:

Mobile phone keypads

LCD display connections

Consumer electronics

Conclusion

FPCBs come in various structures to meet the diverse needs of modern electronics. Whether you need a simple single-sided FPCB or a complex multi-layer rigid-flex PCB, understanding the different types and their applications can help in making informed design choices.

Choosing the right FPCB type depends on factors like circuit complexity, mechanical requirements, and cost considerations. As technology advances, FPCBs will continue to play a crucial role in enabling compact, lightweight, and highly efficient electronic devices.

For more insights on FPCBs and their applications, stay tuned to our blog!