Nitto-denko Corporation

Yousuke Miki

Toshihiko Sugimoto

Chiharu Miyaake

A raw material plastic film like a band stretched in two directions with a machine direction as a longitudinal direction of stretch and a transverse direction as a lateral direction of stretch is prepared. One standard line parallel with the machine direction of stretch is assumed on a film face of the raw material plastic film. An area due to cut a cover layer plastic film and an area due to cut a base layer plastic film (the two areas are of almost the same shape) are assumed to be on the standard line in a state in which the areas are aligned in orientation. However, both an arbitrary point of the area due to cut and the point of the area due to cut corresponding thereto need to be on the standard line. A cover layer plastic film and a base layer plastic film are cut out from the two areas due to cut. Metal electric circuit is formed on a surface of the base layer plastic film via an adhesive layer. The metal electric circuit has a plastic deformation component of 0.0003 (mm/mm) or more when a stress load is imposed until strain becomes 0.002 (mm/mm), and then removed. The cover layer plastic film is stuck on the metal electric circuit via an adhesive layer with the rear face of the plastic film facing the surface of the base layer plastic film, thereby manufacturing a flexible printed circuit.

Flexible printed circuit

A composite sheet comprises a first resin film; and a second resin film laminated on the first resin film; wherein two ellipses of coefficient of linear expansion are created on polar coordinates in corresponding parts of the first and second resin films by a predetermined method and the two ellipse are overlapped so as to match in the center point and coordinate axes X and Y, and the maximum value of a linear expansion coefficient difference between the two resin films is equal to or less than a predetermined value.

Growing community of inventors

Osaka, Japan

Yousuke Miki