Stacked metal and elastomeric dome for key switch

A method of assembling at least a portion of a low-travel keyboard having a quick force drop for a computing device, the method comprising:

• providing a metal dome comprising a dome portion and a first base portion, the first base portion of the metal dome being attachable to a membrane comprising a top layer having a first contact attached to an underside of the top layer, a bottom layer having a second contact attached to a top side of the bottom layer, and a spacer layer between the top and bottom layers having a void between the first and second contacts, the metal dome being collapsible when depressed from above, the metal dome being configured to contact the top layer of the membrane to connect the first and second contacts when the metal dome is deformed;
• disposing an elastomeric dome over the metal dome, the elastomeric dome comprising a second base portion and a plunger portion, the second base portion of the elastomeric dome being attached to the first base portion of the metal dome, the elastomeric dome being collapsible when depressed from above and the plunger portion of elastomeric dome being configurable to impinge the dome portion of the collapsible metal dome when depressed from above and to not contact the dome portion of the metal dome when in a relaxed state;
• and
• attaching key cap to the elastomeric dome such that the plunger portion extends from an underside of the key cap.

A tactile low-travel keyboard for a computing device, comprising:

• a membrane comprising a top layer having a first contact attached to an underside of the top layer, a bottom layer having a second contact attached to a top side of the bottom layer, and a spacer layer between the top and bottom layers having a void between the first and second contacts;
• a metal dome comprising a dome portion and a first base portion, the metal dome being disposed over the membrane and collapsible when depressed from above, the metal dome being configured to contact the top layer of the membrane to connect the first and second contacts when the metal dome is deformed;
• an elastomeric dome disposed over the metal dome and collapsible when depressed from above, the elastomeric dome comprising a second base portion, the second base portion of the elastomeric dome being configured to attach to the first base portion of the metal dome, the elastomeric dome and the metal dome being oriented in a substantially same direction;
• and
• a key cap disposed over the collapsible elastomeric dome and comprising a plunger portion extending from an underside of the key cap, the key cap being attached to the collapsible elastomeric dome, wherein the key cap contacts both the collapsible metal dome and the collapsible elastomeric dome when the key cap is depressed, the plunger portion being operable to collapse the dome portion of the metal dome into contact with the membrane to connect the first and second contacts, and the plunger portion being operable to not contact the dome portion of the metal dome when in a relaxed state.

A key for a keyboard, comprising:

• a key cap;
• a collapsible elastomeric dome comprising a first base portion and a plunger portion, the elastomeric dome being attached to and extending from an underside of the key cap;
• a collapsible metal dome comprising a dome portion and a second base portion, the second base portion being attached to the first base portion of the elastomeric dome, the second base portion of the metal dome being disposed beneath the elastomeric dome and oriented in a substantially same direction as the elastomeric dome, the plunger portion of the elastomeric dome configured to not contact the dome portion of the metal dome when the elastomeric dome is in a relaxed state;
• and
• a membrane comprising a top layer having a first contact attached to an underside of the top layer, a bottom layer having a second contact attached to a top side of the bottom layer, and a spacer layer between the top and bottom layers having a void between the first and second contacts, the second base portion of the metal dome being attachable to the membrane, wherein when the key is fully depressed the elastomeric dome collapses and the plunger portion of the elastomeric dome impinges on the dome portion of the metal dome and collapses the metal dome into contact with the membrane to connect the first and second contacts.