US Patent 7789488 Flexible wiring board and liquid discharge head

In an ink jet recording head including a flexible wiring board, the flexible wiring board has a thickness reduction part formed by reducing a film thickness of a part of the base film. The thickness reduction part is configured to alleviate stress applied to inner leads by a base film in the periphery of a device hole, so as to avoid the failure of bonding or the like caused by the inner leads of the flexible wiring board, on which a recording element substrate is installed.