Flexible printed circuit board and manufacturing method therefor.

摘要

A coil-shaped flexible printed circuit board (1) retains its original outer diameter unchanged without any guide or retainer. For this purpose, either the conductive pattern of copper (3) or synthetic base material (2) is processed to have a permanent stretch before or when the board is wound into a coil shape. A squeezing step may be employed to generate the permanent stretch on the conductive pattern (3). Alternatively, a heat treatment of the base material may be used to form an additional bridged ingredient after the board (1) has been wound. The additional bridged ingredient may retain the coil shape unchanged for a long time without guiding pieces.