06239389 is referenced by 269 patents and cites 182 patents.

A proximity sensor system includes a sensor matrix array having a characteristic capacitance on horizontal and vertical conductors connected to sensor pads. The capacitance changes as a function of the proximity of an object or objects to the sensor matrix. The change in capacitance of each node in both the X and Y directions of the matrix due to the approach of an object is converted to a set of voltages in the X and Y directions. These voltages are processed by digital circuitry to develop electrical signals representative of the centroid of the profile of the object, i.e, its position in the X and Y dimensions. Noise reduction and background level setting techniques inherently available in the architecture are employed.

Title
Object position detection system and method
Application Number
9/337862
Publication Number
6239389 (B1)
Application Date
June 21, 1999
Publication Date
May 29, 2001
Inventor
G√ľnter Steinbach
Palo Alto
CA, US
Robert J Miller
Fremont
CA, US
David Gillespie
Palo Alto
CA, US
Timothy P Allen
Los Gatos
CA, US
Agent
Sierra Patent Group
US
Assignee
Synaptics
CA, US
IPC
G08C 21/00
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