Optical position-measuring device

摘要

An optical position-measuring device senses a relative position of two objects. A reflection material measure is connected to one object and a scanning unit is connected to the other object. A beam is split into three sub-beams in a first splitting plane by a first splitting element. The first and third sub-beams are deflected toward the reflection material measure by the deflecting elements, while the second sub-beam is split into fourth and fifth sub-beams by a second splitting element. The first and fourth sub-beams propagate as a first pair of superimposed sub-beams and the third and fifth sub-beams propagate as a second pair of superimposed sub-beams. The first and second pairs of superimposed sub-beams, after being reflected by the reflection material measure, propagate respectively toward detectors, where the sub-beams in each pair are brought into interfering superposition, so that the detectors detect displacement-dependent scanning signals.

主权项

1. An optical position-measuring device for sensing a relative position of two objects that are movable relative to one another, the optical position-measuring device comprising:
a reflection material measure connected to a first one of the two objects; and a scanning unit connected to a second one of the two objects, the scanning unit being configured to provide relative position information using interfering superposition of at least two pairs of sub-beams, the scanning unit comprising a light source, a first and a second splitting element, deflecting elements and a first, a second, a third and a fourth detector, which are disposed in the scanning unit such that:
a beam incident from the light source is split into at least a first, a second, and a third sub-beam in a first splitting plane by the first splitting element,the first and third sub-beams are deflected toward the reflection material measure by the deflecting elements, while the second sub-beam is split into at least a fourth and a fifth sub-beam by the second splitting element, the first and fourth sub-beams propagating toward a first point of incidence as a first pair of superimposed sub-beams, and the third and fifth sub-beams propagating toward a second point of incidence on the reflection material measure as a second pair of superimposed sub-beams, andthe first and second pairs of superimposed sub-beams, after being reflected by the reflection material measure, propagate respectively toward the first and the second detector, where the sub-beams in each pair are brought into interfering superposition, so that the detectors detect first and second displacement-dependent scanning signals from which, in turn, position information regarding a vertical and a first lateral direction of displacement of the objects is derived, the first lateral direction of displacement extending in the first splitting plane or parallel thereto, wherein the incident beam is additionally split by the first splitting element in the scanning unit into further sub-beams in a second splitting plane which is oriented perpendicular to the first splitting plane, and wherein the sub-beams propagate in the second splitting plane in a manner analogous to the sub-beams in the first splitting plane, so that third and fourth displacement-dependent scanning signals are respectively detected by the third and the fourth detectors, and position information regarding the vertical direction of displacement and a second lateral direction of displacement of the objects is derived from the third and the fourth scanning signals, the second lateral direction of displacement extending in the second splitting plane or parallel thereto.