Position-measuring device

Abstract

A position-measuring device includes a cylindrical object rotatable about a longitudinal axis and having a circumferential annular reflection measuring graduation. A stationary scanning unit is disposed opposite the cylindrical object and has a light source, a transmission grating and a detector. The scanning unit is configured to optically scan the reflection measuring graduation by beams of light emitted from the light source passing through the transmission grating and then striking the reflection measuring graduation, from where the beams of light are reflected back toward the detector, which is configured to generate rotation-dependent position signals. An optically effective perpendicular distance between the detector and the reflection measuring graduation is selected to be one of greater or less than an optically effective perpendicular distance between the transmission grating and the reflection measuring graduation depending on a radius of the cylindrical object.

Dependencies are inferred from the claim text.