Patent · US Expired

Capacitive position sensor with an electrode array cursor and topographically featured scale

US5304937A · kind A · utility

34Cited by
8References
22Claims
0Family size

Inventor

Key dates

Filing dateSep 4, 1992
Grant dateApr 19, 1994
Priority date—
Expiry dateSep 4, 2012

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01D5/2415
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

A capacitive position sensor has a scale (10), having hollow or raised topographical features, and a cursor (20) having an electrode array comprising at least two transmitting electrodes (21a, 21b) and at least one receiving electrode (21c) separated by shielding electrodes (21g). The coupling capacitances (Cac, Cbc) between transmitting and receiving cursor (20) electrodes are modified as a function of the position (x) of the scale topographic feature (11) relative to the cursor, the evaluation of the variation of the signals picked up by the receiving electrode permitting a precise measurement of the relative displacement between scale and cursor.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.