Structure of the flexing section of a multilayer flexible circuit board

A flexible, multi-layer printed circuit, said circuit having a length and a width, said circuit including at least two conductive layers which define wiring patterns of said circuit, each of said conductive layers being supported by a first surface of an associated flexible non-conductive substrate, said substrates having length and width dimensions commensurate with said circuit, and means for bonding said substrates to one another with said conductive layers facing in opposite directions to thereby integrate said conductive layer defined wiring patterns into a unitary multi-layer circuit, said bonding means including at least a first discontinuity which projects over the complete width of said substrates and extends in the direction of the length of said substrates, said discontinuity defining a flexing section of said multi-layer circuit of predetermined size and shape, said substrates not being bonded to one another in said flexing section whereby the individual of said conductive layers may be subjected to different degrees of distortion when said circuit is formed into a non-linear shape by bending in the region of said flexing section.

A flexible, multi-layer printed circuit, said circuit having a length and a width, said circuit including a flexible, non-conductive substrate, said substrate having a pair of oppositely disposed surfaces, a pair of conductive layers which define wiring patterns of said multilayer circuit, each of said conductive layers being supported by a respective surface of said substrate, said substrate having length and width dimensions commensurate with said mull-layer circuit, and means for bonding said conductive layers to said substrate to thereby integrate said conductive layer defined wiring patterns into a unitary multilayer circuit, said bonding means extending substantially the width of said substrate on both surfaces thereof, said bonding means including at least a first discontinuity on one side of said substrate, said discontinuity projecting over the complete width of said substrate and extending in the direction of the length of said substrate, said discontinuity defining a flexing section of said multilayer circuit of predetermined size and shape, said substrate not being bonded to one of said conductive layers in said flexing section whereby said conductive layers may be subjected to different degrees of distortion when said circuit is formed into a non-linear shape by bending in the region of said flexing section.