Contaminent resistant membrane in a dome switch and methods for making the same

A method for constructing a dome switch, comprising:

• aligning a dome with a contact pad of a circuit board;
• applying a sheet to the dome and circuit board, a portion of the sheet covering the dome,
• wherein the portion of the sheet covering the dome includes a plurality of vents, and
• wherein the sheet is formed from a material that is substantially impermeable to air;
• applying a membrane to the sheet,
• wherein the membrane is formed from a material that is substantially permeable to air and substantially impermeable to contaminants, and
• wherein the membrane is positioned above the dome and over the plurality of vents formed in the sheet;
• and
• attaching the sheet and membrane to the circuit board over the dome to secure the dome to the circuit board such that a portion of the sheet comprising the plurality of vents is overlaid on the dome, wherein air within the dome vents through the membrane.

A dome switch, comprising:

• a dome placed on a contact pad, wherein the dome is operative to close an electrical circuit when the dome is at least partially inverted;
• a sheet constructed from a material substantially impermeable to air, the sheet being secured to the dome to form an air tight seal around the dome,
• wherein a portion of the sheet overlaying the dome includes a plurality of vents providing a passage for air through the sheet;
• and
• a membrane coupled to the sheet and positioned between the sheet and the dome,
• wherein the membrane covers the entirety of the plurality of vents formed in the sheet, and
• wherein the membrane is substantially impermeable to contaminants.