Patent ID: 6977347

Claim:
A flexible printed circuit board comprising: a first circuit layer; a second circuit layer facing the first circuit layer; a first adhesive layer disposed on the first circuit layer; an intermediate layer disposed between the first circuit layer and the second circuit layer, and substantially smaller than the first circuit layer and the second circuit layer so that the first adhesive layer directly adheres to the second circuit layer; and a second adhesive layer, facing the first adhesive layer, disposed on the second circuit layer and directly adhered to the first adhesive layer when the first adhesive layer adheres to the second circuit layer, wherein the first circuit layer is provided with a plurality of second through holes, and the first adhesive layer surrounds the second through holes, and the second circuit layer is provided with a plurality of third through holes corresponding to the second through holes respectively, and the second adhesive layer surrounds the third through holes, and the intermediate layer is provided with a plurality of fourth through holes corresponding to the second and third through holes respectively so that the first adhesive layer, surrounding the second through holes, adheres to the second adhesive layer, surrounding the third through holes, through the fourth through holes.