In the design of mobile phone PCB, the FPC flexible circuit board for mobile phone folding needs very good flexibility. At present, domestic mobile phone manufacturers require 80000 to 100000 times for this. Therefore, FPC FPC is a key factor affecting the quality of folding mobile phones. To make a good mobile phone PCB, let’s discuss the FPC FPC end first?
- Material selection: To ensure bending performance, it is recommended to select 0.5mil/0.5oz single-sided substrate, RA calendered copper, and 0.5mil covering film.
- Line design in bending area: there shall be no through hole in the part to be bent; The protective copper wire shall be added at the most two sides of the line. If the space is insufficient, the protective copper wire shall be added at the inner R corner of the bending part; The connecting part of the line shall be designed as an arc.
- Design of bending area: the bending area shall be designed in layers to remove the glue, so as to disperse the stress. The bending area shall be as large as possible without affecting the assembly.
- Shielding layer design: At present, silver paste and copper foil are generally used as the shielding layer of mobile phones, which reduces the actual number of active layers, facilitates assembly, has simple process and low cost. However, the resistance of silver paste is high, about 1 ohm, because it is a mixture. Therefore, the silver paste layer cannot be directly designed as the ground wire. The copper foil shielding layer has two more active layers, which increases the cost, but has low resistance. It can be directly designed as a ground wire. Silver foil shielding layer, the cost is too high.
- Electroplating selection: In order to ensure bending performance, partial copper electroplating process must be selected instead of comprehensive copper electroplating process.