US Patent 7851706 Flexible printed circuit and manufacturing method thereof

A flexible printed circuit including an interior insulation layer, a first conductive layer formed on a surface of the interior insulation layer in a circuit pattern, a first exterior insulation layer deposited to cover the surface of the interior insulation layer and the first conductive layer, a second conductive layer formed on the other surface of the interior insulation layer in a circuit pattern, and a second exterior insulation layer deposited to cover the other surface of the interior insulation layer and the second conductive layer. The flexible printed circuit is manufactured by depositing an interior insulation layer on a base layer, forming a first conductive layer on a surface of the interior insulation layer in a circuit pattern, depositing a first exterior insulation layer to cover the surface of the interior insulation layer and the first conductive layer, removing the base layer, forming a second conductive layer on another surface of the interior insulation layer in a circuit pattern, and depositing a second exterior insulation layer to cover the another surface of the interior insulation layer and the second conductive layer.