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Keyboard switch

  • US 4,508,942 A
  • Filed: 11/28/1983
  • Issued: 04/02/1985
  • Est. Priority Date: 11/30/1982
  • Status: Expired due to Fees
First Claim
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1. A membrane keyboard including:

  • first electrical circuit means having a plurality of first switch contacts;

    second electrical circuit means having a plurality of second switch contacts corresponding to said first switch contacts, said plurality of first switch contacts being equal to said plurality of second switch contacts;

    at least one tactile protrusion formed in said second circuit means, said tactile protrusion projecting out of said second circuit means and away from said first circuit means, said tactile protrusion supporting at least one of said second switch contacts for selective contact with said first switch contacts;

    insulating means between said first and second circuit means, said insulating means having at least one opening aligned with said protrusion to permit selective contact between said first and second switch contacts, said opening being hermetically sealed from the ambient environment;

    flexible cover sheet means planar with the upper surface of said protrusion, said cover sheet enclosing said second electrical circuit means;

    spacer means between said flexible cover sheet means and said second circuit means, said spacer means having at least one cavity surrounding said protrusion; and

    channel means connecting said spacer means cavity with said ambient environment, said channel means being located through at least said first and second electrical circuit means and said insulating means.

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