Patent ID: 6608483
Filing Date: 2003-08-19
Classification: G01R

Abstract:
An electrostatic field sensor comprising:a first set of one or more conducting sensor segments electrically connected together; a second set of one or more conducting sensor segments electrically connected together; a third set of one or more conducting sensor segments electrically connected together; a fourth set of one or more conducting sensor segments electrically connected together; a non-conducting member for supporting and electrically insulating said first, second, third, and fourth sets of conducting sensor segments from each other and from a surrounding structure; means for alternately exposing and shielding said first, second, third, and fourth sets of conducting sensor segments to and from an electrostatic field to be measured that is substantially perpendicular to a surface containing said first, second, third, and fourth sets of conducting sensor segments, said means for alternately exposing and shielding said first, second, third, and fourth sets of conducting sensor segments being operative for producing a first sensor signal from said first set of one or more sensor segments and for producing a second sensor signal from said second set of one or more sensor segments, said first and second sensor signals being alternating signals that are substantially 180 electrical degrees out of phase and that represent a first differential pair signal, said means for alternately exposing and shielding said first, second, third, and fourth sets of conducting sensor segments being operative for producing a third sensor signal from said third set of one or more sensor segments and for producing a fourth sensor signal from said fourth set of one or more sensor segments, said third and fourth sensor signals being alternating signals that are substantially 180 electrical degrees out of phase and that represent a second differential pair signal, said first and second differential pair signals being substantially 90 electrical degrees out of phase.