2 layers flexible circuit board

2 layers flexible circuit board is a circuit having two conductive layers, one on each side of the base layer of polyimide within the circuit. Trace patterns, specific to your needs, can be created on both sides of the substrate film and can be connected where desired with copper plated through-holes. The plated through holes make electrical connections between the 2 layers. The basic stack-up of a double sided circuit with a PSA based stiffener is illustrated below:

Applications
Tightly assembled electronic packages, where electrical connections are required in 3 axes, such as cameras (static application). Electrical connections where the assembly is required to flex during its normal use, such as folding cell phones (dynamic application).Electrical connections between sub-assemblies to replace wire harnesses, which are heavier and bulkier, such as in cars, rockets and satellites. Electrical connections where board thickness or space constraints are driving factors.