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Capacitive keyboard structure

  • US 4,614,937 A
  • Filed: 01/12/1983
  • Issued: 09/30/1986
  • Est. Priority Date: 01/29/1982
  • Status: Expired due to Fees
First Claim
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1. A capacitive keyboard structure comprising a substrate having an upper face which is positioned for access by a user and having a lower face, a series of static sensitive keys disposed on the upper face, each key being associated with a first and a second electrode, one of said electrodes being an emitting electrode which is excited sequentially by an alternating signal delivered by an emitting line connected to said emitting electrode, and the other of said electrodes being a receiving electrode which is coupled capacitively to the emitting electrode by the associated static sensitive key and which impresses on a receiving line connected to the receiving electrode variations of the alternating signal as an effect of the presence of a user'"'"'s finger in the vicinity of such static sensitive key, the first electrode being formed to enclose on the upper face its associated key, and the second electrode being disposed on the lower face below the associated key.

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