Optical position-measuring device

Abstract

An optical position-measuring device for determining the position of a first object relative to a second object movable relative to the first object along a measurement direction includes a scale with a measuring graduation connected to the first object and extending along the measurement direction. A scanner is connected to the second object and includes a fiber-optic array including optical fibers. The fiber-optic array is configured as a fiber-optic plate having an image-input face facing the scale and an image-output face facing the detector array. The fiber-optic array transmits a light pattern into a detection plane of the detector array. An interstitial medium is disposed between the image-output face of the fiber-optic plate and the detector array to ensure that an amount of deflection that the beams exiting the image-output face undergo on a path to the detector array is smaller than in a case without the interstitial medium.

Description

technical field [0001] The invention relates to an optical positioning device. The optical positioning device is suitable for determining the position of the first object relative to the second object. Background technique [0002] A positioning device of this type is known, for example, from EP 0 470 291 B1. The positioning device is used to determine the position of a first object relative to a second object which is arranged movable relative to the first object along at least one measuring direction. In this case, on the one hand, a scale is provided which extends along the first measuring direction and which is connected to the first object. The measuring scale comprises a measuring scale consisting of graduated areas with different optical properties arranged alternately along the measuring direction. On the other hand, a scanning unit is connected to the second object, said scanning unit comprising at least one light source, at least one detection device and at leas...

AI Technical Summary

Problems solved by technology

[0005] In addition, the considerable distortion of the rod lens results in poor imaging of the surface of the code track (codespur) on the side next to the code track

As a result, position errors of the generated position-dependent signal occur in the grating of the rod lens, which are unacceptable for high-precision position measuring devices

[0006] Another disadvantage results from the large length of the rod lens required for the necessary imaging ratio A=1

Such rod lenses typically have a length of 4-6 mm and thus allow a non-compact structural size of the positioning device

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