Patent ID: 11862415
Assignee: FUJITSU COMPONENT LIMITED
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. A key switch device comprising:
an operation member to be depressed;
a switch, disposed under the operation member, including a membrane sheet with an upper layer; and
a reaction force generating member, provided between the operation member and the switch, including:
a first dome that gives a reaction force to the operation member according to depression of the operation member; and
a second dome that includes a bowl part disposed inside the first dome, and a projection projecting downward from a center of the bowl part and depressing the switch disposed below the operation member,

wherein the switch is turned on when an amount of an input stroke of the operation member is larger than a first amount of the input stroke corresponding to a peak load and smaller than a second amount of the input stroke corresponding to a bottom load after the peak load, and
wherein the second dome, combined with deformation of the upper layer of the membrane sheet, has a load displacement characteristic in which a load increase rate increases as the depression amount of the operation member increases.