Is it better to cover the flexible circuit board with copper or silver paste?

Flexible printed circuit board is light, thin, short, small and flexible in structure. The functions of flexible printed circuit boards can be divided into four types, namely, rigid printed boards, which are commonly called hard boards. Flexible printed board: also known as flexible board or flexible board. Rigid-flex PCB: Also known as rigid-flex bonded board 1 1. 1.2 Performance characteristics of flexible PCB (1) The flexible substrate is made of thin film, with small volume and light weight. (2) The flexible board substrate can be bent and folded, and can be used in any geometric equipment body that rigid printed boards cannot be installed. (3) Flexible plates can not only be bent statically, but also be bent dynamically. (4) The flexible circuit reduces the hardware required for interconnection and has higher assembly reliability and output. (5) Flexible circuit can be extended to three-dimensional space, which improves the freedom of circuit design and mechanical structure design. (6) Flexible board can be used as induction coil, electromagnetic shield, touch switch button, etc. (7) Flexible circuits have excellent electrical properties, dielectric properties and heat resistance. (8) Flexible circuits are conducive to heat dissipation: the area/volume ratio of planar conductors is greater than that of circular conductors. In addition, the short thermal channel in the flexible circuit structure further improves the thermal diffusion. 1. Flexible single-sided PCB (2) Flexible double-sided PCB (3) Flexible multilayer PCB according to the number of circuit layers (1) ...