Patent ID: 6946611

Claim:
An keyboard switch, comprising: a membrane sheet having an upper surface and a lower surface; at least one fixed electrode positioned on said upper surface of said membrane sheet; a protruding member affixed to said upper surface of said membrane sheet, said protruding member being selectively movable; at least one movable electrode secured inside said protruding member such that when said protruding member is moved toward said membrane sheet, said movable electrode contacting said at least one fixed electrode; a base plate situated below said membrane sheet such that a gap is formed between said base plate and said membrane sheet; a support structure secured within said gap and positioned to support said fixed electrode and said protruding member; and a ventilation opening penetrating said membrane sheet and positioned inside said protruding member in the vicinity of said fixed electrode; wherein said protruding member and said upper surface of said membrane sheet define a first air space, wherein said lower surface of said membrane sheet, said support structure and said base plate define a second air space, and wherein said first air space is connected to said second air space through said ventilation opening such that all air escaping from said first air space is accommodated within said second air space.