05099386 is referenced by 18 patents and cites 36 patents.

A variable-capacitance transducer detects the angular position of a rotatable member. The transducer includes a first capacitance plate having a plurality of electrically conductive capacitance electrodes, a second capacitance plate spaced therefrom, and a dielectric element located between the plates. At least two of the electrodes are interconnected by a conductive trace. The dielectric element or one of the plates is fixedly mounted on the rotatable member. The electrodes on the first capacitance plate, in conjunction with the second capacitance plate, form a plurality of capacitances that vary as the angular position of the rotatable member changes. A conductive guard partially envelopes the conductive trace and a conductive guard partially envelopes the electrodes on the first capacitive plate. A spacer defines the distance between the capacitance plates and has a coefficient of thermal expansion and dimensions that cause the distance between the capacitance plates to vary by an amount calculated to compensate for changes in plate area with temperature. The transducer includes a parasitic capacitor plate having a position that is adjustable to compensate for parasitic capacitance. An electromagnetic shield is constructed and positioned, with respect to a driver that controls the rotatable member, such that the shield tends to prevent electromagnetic radiation from the driver from affecting the capacitances between the capacitance plates.

Title
Variable-capacitance position transducing
Application Number
585890
Publication Number
5099386
Application Date
May 13, 1991
Publication Date
March 24, 1992
Inventor
Jean I Montagu
Brookline
MA, US
Steven M Burgarella
Framingham
MA, US
Albert K Bukys
Ashland
MA, US
Stephen O Dea
Wilmington
MA, US
Pierre Brosens
Belmont
MA, US
Brian P Stokes
Windham
NH, US
Agent
Fish & Richardson
Assignee
General Scanning
MA, US
IPC
G01R 27/26
H01G 5/06
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