Introduction to FPC Connectors

Author：danny / time：2018-12-18 / The number of clicks：358

The Flexible Printed Circuit connectors on the market are abbreviated as FPC connectors. They feature the high cable density, lightness, and thinness, so it’s called a soft circuit board, soft printed circuit board, or flexible circuit board. Most FPC connectors are manufactured with polyimide (PI) or polyester film (PET) as its raw material, which increases the reliability of FPC connectors.

In fact, the FPC connectors may vary according to the different ways it connects the raw materials and the copper clad. So, FPCs can be divided into two major types: 3 layer FCCL and 2 layer FCCL. Each of the two models has its advantages and disadvantages. The 2 layer FCCL has more flexibility, a stronger connection between the raw material and the copper clad, and a higher flatness parameter of the pad, so it can be applied to equipment with a higher requirement of the two properties, such as CHIP ON FLEX. Yet, it is too costly to be widely used in the market. In contrast, 3 layer FCCL is much cheaper and is commonly used in the market. However, its flexibility and flatness parameter of pad are inferior to the 2 layer FCCL, so it may have welding flaws like cracks, which manufacturers should try to avoid. 

Since the 3 layer FCCL is more prevalent on the market, more corporations have adopted it, and it is better developed. Corporations have categorized the 2 layer FCCL different types according to the number of copper foil layers, including the multiple layer board, double-sided board, single layer board, and double layer board, etc. 

The single layer board has the simplest structure. Corporations usually use a structure that includes raw material, transparent plastic, and copper foil. Some companies apply a structure that includes a layer of protective plastic and transparent plastic. The structure can greatly enhance the mechanical strength of the 3 layer FCCL.
　　

The double layer structure is used for complex circuits which cannot be wired or masked.

   A multi-layer board is different from the single-layer board in the VIA structure, which can effectively connect different layers of copper foil.

The double-sided board is welded on both sides, and it is mainly used to connect with other circuit boards.

In sum, FPC connector can be applied to MP3 and MP4 players, digital cameras, cell phones, and cell phone batteries. It has a prospective future.