Optical positioning device

摘要

The measuring device comprises a measuring standard (10) connected to an object and including an incremental graduation (12) extending in measuring direction (X), scanning unit (20) connected to other object and including a light source (23), grating (26), and detector system (27). The detector system has several groups of detector elements. The centroid of detector elements of a group is identical to the centroid of detector elements of each other group. The periodic diaphragm structures (29) are arranged in front of a light-sensitive region of detector elements. The optical position-measuring device comprises a measuring standard connected to one of the two objects and including an incremental graduation extending in the measuring direction, and a scanning unit connected to the other object and including a light source, a grating, and a detector system. The detector system includes several groups of detector elements arranged in a detection plane and adapted to generate several position-dependent, phase-shifted scanning signals, in response to relative movement of the two objects, by scanning a periodic fringe pattern resulting in the detection plane. Each group of detector elements has in-phase scanning signals. The sum of areas of the detector elements of a group is identical to the sum of areas of the detector elements of each other group. The centroid of the detector elements of a group is identical to the centroid of the detector elements of each other group. The periodic diaphragm structures are arranged in front of a light-sensitive region of the detector elements.