Patent ID: 7528325

Claim:
A key sheet module, comprising: a single-sided printed wiring board including a front surface on which a plurality of wiring patterns are provided and further including a plurality of holes which pass through the single-sided printed wiring board and are provided at positions corresponding to rear-surface connection parts of the wiring patterns; a plurality of contact springs disposed on the wiring patterns for switching of the wiring patterns; an insulating layer provided on the wiring patterns, and having openings provided at positions corresponding to the contact springs and front-surface connection parts of the wiring patterns, respectively; a front-surface jumper to electrically connect the front-surface connection parts exposed in the openings of the insulating layer; and a rear-surface jumper to electrically connect the rear-surface connection parts exposed in the holes of the single-sided printed wiring board; a fixation sheet to cover a surface of the contact spring.