FPC soft printed circuit board, referred to as soft board, is made of soft plastic film (PI), copper foil (CU) and adhesive, with excellent flexibility and reliability. Surface treatment process of FPC pressure screen cable:
Electrogilding: strong adhesion, good bonding performance and good ductility. Plug in FPC must be electroplated.
Chemical gold: poor adhesion, good uniformity, can not be bound, easy to crack.
FPC can be divided into single panel, double panel, layered panel, multi-layer layered panel, soft and hard bonding panel, etc. FPC with more than two layers of panels are connected to each layer through through holes. Structural material of FPC pressure screen cable:
- Base course: the material is generally PI polyimide, and also PET polyester. The material thickness is 12.5, 25, 50, 75 and 125 um. 12.5 and 25 um are commonly used. PI is superior to PET in various properties.
- Copper foil layer: calendered copper and electrolytic copper with thickness of 18, 35 and 75 um. As the calendered copper has better mechanical properties than electrolytic copper, the calendered copper is preferred among FPC pressure screen flat wires that need to be bent frequently. The copper foil thickness of main screen FPC is generally 18um.
- Covering layer: the material is the same as that of the base layer, which is covered on the copper foil for insulation, resistance welding and protection. The thickness of common material is 12.5um.
- Glue: It is used for bonding each layer.
- Reinforcing plate and reinforcing film: for plug-in FPC, in order to cooperate with the standard socket, a reinforcing plate shall be added at the back of the contact surface, and the materials can be PI, PET and FR4; Common PET. The thickness of the contact position of the stiffening plate after fitting is determined according to the requirements of the socket, generally 0.3, 0.2 or 0.12mm. For the FPC end that needs to be bonded to the LCD, it is necessary to design a reinforced film on the back of the contact surface, using 12.5um PI material.