Measuring device for capacitive determination of the relative position of two with respect to one another moveable parts

Claim 1

A measuring device for capacitative determination of the relative position of two relatively movable parts with respect to one another, such as the scale and a slide of a hand manipulated measuring device comprising a slide provided with a number of groups of supply electrodes distributed along the direction of relative movement, each of the groups having n number of supply electrodes, n being an integer greater than 2, signal generator means having n number of signal outputs, each of the supply electrodes in each group being connected to a respective one of said signal outputs whereby all supply electrodes are supplied with voltages according to a cyclic pattern, the slide also being provided with at least one receiving electrode, a signal processing unit connected to at least one receiving electrode, the scale being provided with a single electronic pattern comprising internally galvanically isolated scale electrodes, each scale electrode comprising two mutually galvanically connected parts, one being a detecting part and being located close to the area of the scale over which the supply electrodes of the slide can be moved, the other of the two parts being a transferring part and being located close to the area over which the at least one receiving electrode of the slide can be moved, whereby the position of the slide along the scale generates a signal from the at least one receiving electrode which is derived from at least two adjacent supply electrode signals and the position of the slide with respect to the scale can be determined by the identification in the signal processing unit of the signals and their amplitude ratio.