05920309 is referenced by 315 patents and cites 14 patents.

Method and apparatus for sensing the simultaneous proximity of one or more fingers or other appropriate objects to a capacitive touch sensor. A modulator/demodulator pair drive and sense either a single trace or a pair of traces. In a dual trace embodiment, differentially sensed signals are then peak detected converted from voltage to current. The output signal is then calibrated to adjust for trace variations, followed by appropriate gain and level shifting, and analog-to-digital conversion for use as the input to a microcontroller.

Title
Touch sensing method and apparatus
Application Number
8/582769
Publication Number
5920309
Application Date
January 4, 1996
Publication Date
July 6, 1999
Inventor
Aleksey Tareyev
Vlyanovsk
RU
Berni Joss
Palo Alto
CA, US
Bernard Kasser
Menlo Park
CA, US
Stephen J Bisset
Palo Alto
CA, US
Agent
Townsend and Townsend and Crew
Assignee
Logitech
CA, US
IPC
E08C 21/00
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