Patent ID: 7655869

Claim:
A flex-rigid wiring board comprising: a rigid substrate having a conductive layer including an interconnecting electrode pad; a flexible substrate having a conductive layer including an interconnecting electrode pad, the flexible substrate being lap-joined and electrically connected to the rigid substrate; and an insulative adhesive interposed between portions of the rigid and flexible substrates and lap-joining the rigid substrate and the flexible substrate such that the flexible substrate provides a flexible portion, wherein the interconnecting electrode pads on the rigid and flexible substrates are electrically connected to each other through a conductor lump penetrating the insulative adhesive, one of the interconnecting electrode pads on the rigid and flexible substrates has an area of contact with the conductor lump which is smaller and which has an area So, the conductor lump and the one of the interconnecting electrode pads on the rigid and flexible substrates from an area of contact S 1 , and the area So and the area of contact S 1 have a ratio S 1 /So which is 0.4≦S 1 /So≦0.9.