Sunarrow Limited

Hisashi Ishii

Minoru Yoshida

Portable phones are getting a trend that s design and thinner configuration becomes more important. Therefore, in order to meet this demand, the entire key top is made of a thin metal, and a thin resin layer is provided on the back surface of the key top and further letter holes are filled with a resin. According to those, the adhesiveness of the key top is improved as well as improvement of hand feeling. In addition, a printed layer for coloring the letters can be provided on the back surface of the key top.

Key sheet and production method thereof

Preparing a resin film having a transparency and a thickness of 0.2 mm or less such as PC, PET, PU or the like; drawing the resin film in such a manner to form concave portions at positions corresponding to a plurality of the key tops of the resin film by pinching the resin film between heating drawing dies; forming a pressing element on the undersurface of the film by filling a filler (resin) into the concave portion formed by means of the drawing; and disposing the key tops by means of adhesion, the key tops formed on the top surface of the resin film by means of the resin formation, the mold printing or the like after the formation of the pressing elements, which achieves further thinner configuration of the key sheet with the configuration that the key tops and the pressing elements are disposed, respectively on the top surface and the undersurface of the resin film.

Growing community of inventors

Niigata, Japan

Hisashi Ishii