Part 2: The Base of the Flexible PCB LED Strip: Flexible PCB
A flexible PCB or FPC is a bendable circuit board that can be single-sided, double-sided, single-layer, dual-layer, or multilayer.
Structure of a flexible PCB: an FPC is made up of a polyimide (PI) substrate layer, two rolled copper foil on the two sides, and two external PI layers to insulate and protect the copper. Between the PI substrate and copper foil, there can be an adhesive layer. The flexible PCB without adhesive has the PI color, and the flexible PCB with the adhesive has a darker color.
If a flexible PCB has two or more layers, it is manufactured by laminating the alternating layers of copper, PI, (and adhesive) on the substrate layer.
The FPC has very thin substrate materials, and the rolled copper foil greatly increases the circuit's ductility and repeatable bending ability. Flexible PCBs reduce much of the space and match the non-planar assembly applications.