US 11,862,415 B2
Keyswitch device and keyboard
Hiromi Ohtsuka, Tokyo (JP); Daisuke Taga, Tokyo (JP); Takuya Saitou, Tokyo (JP); and Momosuke Nakahara, Tokyo (JP)
Assigned to FUJITSU COMPONENT LIMITED, Tokyo (JP)
Filed by FUJITSU COMPONENT LIMITED, Tokyo (JP)
Filed on Jul. 24, 2020, as Appl. No. 16/938,470.
Application 16/938,470 is a continuation of application No. 14/264,652, filed on Apr. 29, 2014, granted, now 10,763,054.
Claims priority of application No. 2013-102410 (JP), filed on May 14, 2013.
Prior Publication US 2020/0357581 A1, Nov. 12, 2020
This patent is subject to a terminal disclaimer.
Int. Cl. H01H 3/12 (2006.01); H01H 13/79 (2006.01); H01H 13/807 (2006.01)
CPC H01H 3/125 (2013.01) [H01H 13/79 (2013.01); H01H 13/807 (2013.01); H01H 2203/02 (2013.01); H01H 2203/038 (2013.01); H01H 2203/054 (2013.01); H01H 2215/006 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A reaction force generating member that contacts an upper layer of a membrane sheet, comprising:
a first dome, having a first load displacement characteristic, that gives a reaction force to an operation member according to a depression of the operation member; and
a second dome, having a second load displacement characteristic, that includes a bowl part disposed inside the first dome, and a projection projecting downward from a center of the bowl part and depressing a switch disposed below the operation member,
wherein
the first load displacement characteristic increases a depression load of the operation member until the first dome performs buckling deformation according to depression of the operation member, the depression load of the operation member reaches a peak load, and the depression load of the operation member decreases after the buckling deformation,
the second load displacement characteristic, combined with deformation of the upper layer of the membrane sheet, increases the depression load of the operation member nonlinearly according to a depression amount of the operation member, and
when the depression load of the operation member in a total of the first load displacement characteristic, the second load displacement characteristic and the deformation of the upper layer of the membrane sheet decreases after the peak load and before the depression load of the operation member reaches a bottom load which is a minimum load after the peak load, the projection turns on the switch, and
wherein the second load displacement characteristic has a load increase rate that increases as the depression amount of the operation member increases.