Capacitive matrix sensing method and apparatus
US T904008 I4
Description (OCR text may contain errors)
DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 O.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public-for inspection and reproduction may be purchased for 30 cents a sheet.
Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Oflice makes no assertion as to the novelty of the disclosed subject matter.
PUBLISHED NOVEMBER 7 1972 T904,008 CAPACITIVE MATRIX SENSING METHOD AND APPARATUS William George Crouse, Raleigh, N.C., assignor to International Business Machines Corporation, Armonk,
Filed Nov. 30, 1971, Ser. No. 203,390 Int. Cl. G08c 1/00 US. Cl. 340--365 C 2 Sheets Drawing. 14 Pages Specification A low impedance current integrating amplifier is utilized as a sensor for a high impedance capacitive matrix in which changes in capacitance at the cross points of the matrix which depart from a given threshold value are to be sensed.
Nov; '1972 w. G. CROUSE CAPACITIVE MATRIX SENSING METHOD AND APPARATUS 2 Sheets-Sheet 1 Filed Nov. 30, 1971 g L in L RL L L L 1 1 2 a 4 n-2n-1 n ILFL SIGNAL DRIVE CONNECTOR GEN RS 1 a v Nov. 7, 1972 CRQUSE T904,008
CAPACITIVE MATRIX SENSING METHOD AND APPARATUS Filed Nov. 30, 1971 2 Sheets-Shem 2 6V in