Patent ID: 8367950

Claim:
A key module for a mobile device including: a key top part that is depressed by an operator, thereby inputting a signal; a base plate on which a fixed-side contact for generating the signal is disposed; a movable-side contact that is disposed on the key top part side of the fixed-side contact and is depressed by the key top part, thereby deforming and connecting to the fixed-side contact and generating the signal; a movable-side contact sheet that covers the movable-side contact in order to fix the movable-side contact on the base plate; and a light guide plate that is disposed on the key top part side of the movable-side contact sheet, causes light emitted by a light source, disposed on a side of the light guide plate, to propagate within the light guide plate, and exits the light from an exit surface of the light guide plate on the key top part side, wherein the light guide plate is formed by inkjet printing a dot pattern in white ink onto a surface of a base material formed from a thermosetting polyurethane elastomer sheet, which surface is opposite to the exit surface of the light guide plate.