Photoelectric position measuring system
AssigneeDr. Johannes Heidenhain GmbH
InventorWalter Huber
Life of this patent
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Abstract
A scanning grating is provided in a photoelectric position measuring system which has three areas per graduation period (d) arranged behind each other in the measuring direction. These areas B.sub.1, B.sub.2, B.sub.3 are structured transversely with respect to the measuring direction X in such a way that transversely diffracted light beams are directed on detectors D.sub.0, D.sub.1, D.sub.2 which are arranged transversely to the measuring direction X. The detectors generate signals which are phase-shifted with respect to each other.
Claims14
A photoelectric position measuring system wherein light from a light source is modulated as a function of position by a plurality of gratings, which can be displaced in the measuring direction relative to one another, wherein light beams are diffracted on at least one of the gratings and interfere with each other where a plurality of photo-detectors are provided for detecting position-dependent signals which are phase-shifted with respect to each other, the measuring system comprising:
- at least one of the gratings having at least three areas within each one of its graduation periods (d) oriented in the measuring direction (X) the areas disposed behind each other in the measuring direction and essentially extending perpendicularly with respect to the measuring direction, wherein each one of these areas has different directionally selective properties, and that each signal light beam deflected from these areas impacts an associated photo-detector, wherein the photo-detectors are disposed essentially transversely with respect to the measuring direction.
A photoelectric position measuring system wherein light from a light source is modulated as a function of position by a plurality of gratings, which can be displaced in the measuring direction relative to one another, wherein light beams are diffracted on at least one of the gratings and interfere with each other where a plurality of photo-detectors are provided for detecting position-dependent signals which are phase-shifted with respect to each other, the measuring system comprising:
- at least one of the gratings having at least three areas within each one of its graduation periods (d) oriented in the measuring direction (X) the areas disposed behind each other in the measuring direction and essentially extending perpendicularly with respect to the measuring direction, wherein each one of these areas has different directionally selective properties, and that each signal light beam deflected from these areas impacts an associated photo-detector, wherein the photo-detectors are disposed essentially transversely with respect to the measuring direction, wherein the scanning grating supports a screen-like amplitude structure, which is oriented transversely to the scanning direction, for screening out undesired signal portions.
Dependencies are inferred from the claim text.