Darlox Electronics Co., Ltd.: Fpc Layered Structure
Flexible Printed Circuit(FPC) is favored for its light weight, thin thickness, free bending and folding. However, the quality inspection of FPC in China still relies mainly on manual visual inspection, with high cost and low efficiency. With the rapid development of electronic industry, circuit board design is becoming more and more accurate and dense. The traditional manual inspection methods can no longer meet the needs of production. Automatic detection of FPC defects has become an inevitable trend of industrial development.
In consumer electronic products with movable structure(such as side slide phones), in order to make the products slide more than 150000 times in the bending state, a single FPC(flexible circuit board) is usually used to connect two different modules. With the development of smart phones, their working frequency and transmission speed are getting higher and higher. If MIPI or MDDI and other interface protocols are used, the impedance of the differential dual path must be controlled within a certain range so that the differential dual signal corresponds to the layer reference plane. In the prior art, FPC design usually uses one or two layers of copper foil as the reference plane, so the cost is doubled. At the same time, as the number of copper foil layers increases, the thickness of FPC will increase, thus sliding. The performance is greatly reduced and the number of FPC slides is reduced, which will affect the product life. If impedance control is not performed in the sliding area, the product performance will be degraded.
Edit Default Structure
Copper film
Copper foil: basically divided into electrolytic copper and rolled copper. Typical thickness is 1/2oz and 1/3oz
Substrate membrane: the common thickness is 1mil and 1/2mil.
Adhesive(adhesive): the thickness is determined by the customer’s requirements.
Cover film
Peritoneal protective film: used for surface insulation. Typical thicknesses are 1 mm and 1/2 mm.
Adhesive(adhesive): the thickness is determined by the customer’s requirements.
Profiled paper: Do not let the adhesive stick to foreign matters before pressing. Simple operation.
Intensifying film(PI intensifying film)
Reinforcing plate: strengthen the mechanical strength of FPC, and facilitate surface installation and operation. The general thickness is 3 to 9 mm.
Adhesive(adhesive): the thickness is determined by the customer’s requirements.
Profiled paper: Do not let the adhesive stick to foreign matters before pressing.
EMI: electromagnetic shielding film(strong electromagnetic area or area easy to be interfered with) that protects the internal circuit of the circuit board from external interference.