To eliminate uneven illumination at the time of illuminating button keys by back light.
A button key 1 is made of a translucent silicone rubber and has pluralities of buttons 11 projected to the front side. Each button 11 is translucent and seen bright by illumination from a downside. A film sheet key 2 is stuck to a lower face of the button key 1. A PET film is used for the sheet key 2, which is originally transparent but colored cloudy so that light is reflected and diffused. Furthermore, a contact part 21 is conductively printed to a lower face of the sheet at a position corresponding to each button of the button key 1 and the sheet 2 is adhered to the lower face of the button key 1 by directing the contact parts 21 downward. In the case of using the adhered and laminated button sheet keys that are mounted on the portable telephone set, illumination from an LED light source of back light of the portable telephone set is diffused by the cloudy PET of the sheet key 2 and the button key is seen bright without uneven illumination when observing the button key from the front face.
TAKAYASU TETSUFUMI
SATO TAKESHI
