ILLUMINATION TYPE KEY SHEET, ILLUMINATION TYPE PUSH BUTTON SWITCH, AND PUSH BUTTON ILLUMINATION METHOD OF PORTABLE INFORMATION TERMINAL

摘要

PROBLEM TO BE SOLVED: To provide an illumination type key sheet capable of illuminating a specific key top selectively, even in the case the key sheet has a plurality of key tops on the upper face of a base sheet, an illumination type push button swtich, and a push button illumination method of a portable information terminal.;SOLUTION: At the base sheet 11, an opening part 13 is installed for light shielding to shield a light guide in the wall thickness of the base sheet 11 between mutually adjacent key tops 12, and a projection part 16 for incident light is installed to take in light from a light source of a substrate on the opposed face side to the substrate. By this, the light traveling in the wall thickness of the base sheet 11 can be shielded by the opening part 13 for light shielding interposed between the adjacent key tops 12. Moreover, the light from the light source can be taken in efficiently by receiving it by the projection part 16 for the incident light, and the specific key top 12 out of the plurality of key tops 12 can be illuminated at high brightness.;COPYRIGHT: (C)2007,JPO&INPIT