Scanning unit for a position measuring device

Abstract

A scanning unit for a position measuring device for scanning a measuring graduation of the position measuring device, includes a scanning structure that is provided on a carrier and is formed such that, by interaction of an electromagnetic radiation, used for scanning the measuring graduation, with the measuring graduation on one hand and with the scanning structure on the other hand, a periodic stripe pattern is generated. A detector arrangement is provided for detecting the stripe pattern, which is made up of a plurality of detector elements of different phases, arranged one after another, that generate output signals having a phase shift represented by those phases, the arrangement of detector elements of different phases one after another forming a periodic pattern, and each of the detector elements being assigned exactly one region of the scanning structure referred to as a bar, and the detector elements being combined to form two detector groups such that at least detector elements of the same phase belong to the same detector group, and the detector elements within one detector group being interconnected for generating a detector signal. The bars of the scanning structure are formed and arranged such that the totality of the bars assigned to the first detector group and the totality of the bars assigned to the second detector group in each case cover an active area of equal size on the carrier of the scanning structure. The area center of gravity of the area covered by the totality of the bars assigned to the first detector group on one hand, and the area center of gravity of the area covered by the totality of the bars assigned to the second detector group on the other hand coincide.

Dependencies are inferred from the claim text.