Abstract: A flexible printed circuit board includes: a base film that has electrical insulation property; a conductive pattern that is formed on the base film and including a pair of differential signal lines and a ground line; an insulating layer that is formed on the conductive pattern; a conductive layer that is formed on the insulating layer; and a connecting portion that electrically connects the ground line and the conductive layer through a penetration hole formed on the insulating layer.

Abstract: According to one embodiment, a printed wiring board includes a first layer which has a plurality of grooves disposed in a bent area, and each length direction of the plurality of grooves intersects to a bending direction, and a second layer which is disposed on a face of a side opposed to a face with the grooves of the first layer disposed thereon.

Abstract: Disclosed is a wiring board including a first polyimide layer of heat-cured photosensitive polyimide, a copper layer pattern formed by growing an electrolytic copper plating layer on the polyimide layer, and a second polyimide layer of heat-cured photosensitive polyimide, the second polyimide layer covering the copper layer pattern. Also, disclosed is a magnetic disc apparatus including this wiring board, a head carriage having an electric connection to the wiring board and having a head mounted thereon to perform input/output of electric signals transmitted bilaterally via the connection, and a magnetic disc on which reading/writing of magnetic information are performed by the head mounted on the head carriage.

Abstract: A wiring board is constructed such that a base layer constituted of photosensitive polyimide, a conductor layer constituted of copper, and a cover layer constituted of photosensitive polyimide are formed in this order on a stainless layer. On an electronic part mounting portion, a plurality of lands are formed so as to correspond to electrode terminals of an electronic part to be mounted. On the periphery of the electronic part mounting portion, an underfill diffusion preventing portion formed by removing the cover layer in a trench shape is provided so as to surround the periphery thereof.