Patent ID: 7138808
Filing Date: 2006-11-21
Classification: G01D

Abstract:
1. A moveable apparatus comprising: a movable part having a first electrode; a stationary part having a second electrode, wherein said first and second electrodes constitute a capacitor; and wherein said second electrode is enclosed in a guard electrode with a first insulator in between such that said second electrode can detect the amount of movement of said moveable part from changes in the electrostatic capacity of said capacitor; wherein said movable apparatus is connected to one terminal of a triaxial cable comprising a first or core conductor, a second conductor covering said first conductor, and a third conductor covering said second conductor, said first electrode is connected to said third conductor, said second electrode is connected to said first conductor, and said guard electrode is connected to said second conductor; a fourth conductor disposed in said stationary part, wherein said fourth conductor is insulated from said guard electrode and is electrically connected to said first electrode, and wherein said second electrode, said guard electrode, and said fourth conductor together form a triaxial structure.