FPCsupplier talked FPC types, how much do you know?

Single layer FPC

It has a layer of chemically etched conductive pattern, and the conductive pattern layer on the surface of the flexible insulating substrate is a rolled copper foil.The insulating substrate can be polyimide, polyethylene terephthalate, aramid cellulose ester and polyvinyl chloride.Single-layer FPC can be divided into the following four sub-categories:

Single-sided connection without covering

The wire pattern is on the insulating substrate, and there is no covering layer on the wire surface.The interconnection is realized by soldering, welding or pressure welding, which is commonly used in early telephones.

Single-sided connection with overlay

Compared with the previous type, it only has an extra layer of covering on the surface of the wire.The pads need to be exposed when covering, and it can simply be left uncovered in the end area.It is the most widely used and widely used single-sided flexible PCB.It is used in automobile instruments and electronic instruments.

Single-layer FPC

Double-sided connection without covering layer

The connection pad interface can be connected on the front and back of the wire.A via hole is opened on the insulating base material at the pad.This via hole can be punched, etched or made by other mechanical methods at the required position of the insulating base material.become.

Double-sided connection with cover layer

The difference between the previous type is that there is a covering layer on the surface, and the covering layer has via holes to allow termination on both sides while still maintaining the covering layer.It is made of two layers of insulating materials and a layer of metal conductors.

Double-sided FPC

Double-sided FPC

The double-sided FPC has a conductive pattern made by etching on both sides of the insulating base film, which increases the wiring density per unit area.The metallized hole connects the patterns on both sides of the insulating material to form a conductive path to meet the design and use function of flexibility.The cover film can protect single and double-sided wires and indicate where the components are placed.According to requirements, metallized holes and covering layers are optional, and this type of FPC has fewer applications.

Multilayer FPC

Multi-layer FPC is to laminate 3 or more layers of single-sided or double-sided flexible circuits together, and form metallized holes by drilling and electroplating to form conductive paths between different layers.In this way, no complicated welding process is required.Multilayer circuits have huge functional differences in terms of higher reliability, better thermal conductivity and more convenient assembly performance.

Multi-layer FPC

The advantage is that the base film is light in weight and has excellent electrical properties, such as a low dielectric constant.The multi-layer flexible PCB board made of polyimide film as the base material is about 1/3 lighter than the rigid epoxy glass cloth multi-layer PCB board, but it loses the excellent single-sided and double-sided flexible PCB.Most of these products do not require flexibility.Multi-layer FPC can be further divided into the following types:

Finished flexible insulating substrate

This type is manufactured on a flexible insulating substrate, and the finished product is specified to be flexible.This structure usually bonds the two-sided ends of many single-sided or double-sided microstrip flexible PCBs together, but the central parts of them are not bonded together, thus having a high degree of flexibility.In order to have a high degree of flexibility, a thin, suitable coating, such as polyimide, can be used on the wire layer instead of a thicker laminated cover layer.

Finished product

Finished soft insulating substrate

This type is manufactured on a flexible insulating substrate, and the finished product can be flexed.This type of multi-layer FPC is made of a flexible insulating material, such as polyimide film, laminated to make a multi-layer board, and loses its inherent flexibility after lamination.

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