Capacity responsive keyboard

  • US 5,087,825 A
  • Filed: 02/15/1990
  • Issued: 02/11/1992
  • Est. Priority Date: 02/15/1990
  • Status: Expired due to Term
First Claim
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1. A capacity responsive keyboard system comprising:

  • a substrate having a plurality of electrically conductive plate members mounted thereto, said plate members being insulated from each other;

    a substantially rigid dielectric member overlying said plate members having a surface facing said plate members;

    a plurality of electrically conductive transmission members, each of said transmission members being a compressible conductive polymer extending between said dielectric member and one of said plate members in order to provide an airtight interface with said dielectric member and with the associated one of said plate members; and

    circuit means connected with said plate members and responsive to capacity between said plate members and ground for providing a signal indicative of a change in capacity between at least one of said plate members and ground.

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