High density flexible wiring board

A high density flexible wiring connection device comprising:

• a flexible flat cable having narrow-pitch parallel conductors;
• a flat cable connector having a double-sided contact designed for narrow-pitch wiring and having upper and lower contact terminals to be electrically connected to the narrow-pitch conductors of the flexible flat cable, the flat cable connector being mounted on a printed circuit board;
• and
• an supplementary wiring board having upper wiring terminals and lower wiring terminals provided on upper and lower surfaces thereof for connecting the flexible flat cable and the flat cable connector, such that one ends of the upper wiring terminals of the supplementary wiring board are connected to alternate ones of the narrow-pitch conductors, and one ends of the lower wiring terminals of the supplementary wiring board are connected to the other alternate ones of the narrow-pitch conductors, while the other ends of the upper wiring terminals of the supplementary wiring board are connected to alternate ones of the upper contact terminals of the flat cable connector, and the other ends of the lower wiring terminals of the supplementary wiring board are connected to alternate ones of the lower contact terminals of the flat cable connector, whereby the upper wiring terminals as well as the lower wiring terminals of the supplementary wiring board have a wide pitch twice as large as the narrow pitch of the narrow-pitch conductors, thereby preventing whiskers from causing short-circuits between adjacent ones of the upper contact terminals and between adjacent ones of the lower contact terminals of the flat cable connector.