Elastic switch device having vent cavity

A switch device, comprising:

• a substrate provided with at least one first contact and including at least two through holes;
• and
• a contact rubber, being an elastic sheet covering one side of the substrate, provided with at least one dome-shaped cavity configured to make a second contact portion including a second contact corresponding to the first contact elastically deformable and capable of contacting to and separating from the first contact,
• a cover member disposed over an opposite side of the substrate such that an inner space is defined therebetween;
• a vent cavity portion having a fixed shape and formed in the elastic sheet, and
• an air groove communicating with the cavity and the vent cavity portion between the substrate and the elastic sheet,
• wherein the through holes communicate with both the inner space and the vent cavity portion and are independent through holes that are not electrically connected to a circuit of the substrate,
• wherein no contact is disposed in the vent cavity portion,
• wherein when plural dome-shaped cavities are provided in the contact rubber, the vent cavity portion is not disposed between plural ones of the dome-shaped cavity,
• wherein the at least two through holes correspond to and communicate with the same vent cavity portion on the substrate, and
• wherein the cover member comprises a ridge portion which together with the substrate define a vent recess which communicates with the inner space.