Patent ID: 6525311
Filing Date: 2003-02-25
Classification: G01D

Abstract:
A scanning unit for an optical position measuring device, which is suitable for scanning a scale in a measurement direction, comprising:a light source; an incremental signal scanning arrangement, disposed symmetrical around the light source and comprising a plurality of incremental signal detector elements, which are each disposed relative to one another so that phase-offset partial incremental signals are generated from the scanning of an incremental grating line of a scale; a first reference pulse detector element and a second reference pulse detector element, each of which are disposed vertically to a measurement direction and are each adjacent to the incremental signal scanning arrangement and generate an output reference pulse signal from the scanning of a first reference marking and a second reference marking located at one or more defined reference positions of the scale; and a plurality of compensation detector elements that generate a compensation signal with a constant signal level.