Patent ID: 6642920
Filing Date: 2003-11-04
Classification: G06F,H01H,H04M

Abstract:
A key input device comprising a seesaw switch unit (4) mounted on a base, and a key rubber (8) provided on the base covering the seesaw switch unit (4), a seesaw key (10) provided on the surface of the key rubber (8) for depressing the seesaw switch unit (4), the seesaw switch unit (4) comprising a base plate (5), a dome sheet (7) provided on the base plate (5) and having a plurality of dome portions (71)(72), and a pivotally movable member (6) with a plurality of projectors provided over the dome sheet (7) to selectively depress each dome portion (71), the seesaw key (10) disposed over the pivotally movable member (6), a dome portion being elastically restorably invertable by being depressed by the pivotally movable member (6) to bring a dome-shaped contact terminal (52) formed on an inner surface of the dome portion into contact with a contact electrode (51) formed on a surface of the base plate (5) and closing contacts;wherein one of the plurality of projectors is larger than all others of said plurality of projectors so as to provide an seesawing effect for the seesaw switch unit 4.