초록 ▼

An accurate and reliable device for controlling the position of a first body, of which the devices forms part, relative to a second body is described. The edge of the image of the second body is periodically moved over a row of radiation-sensitive detectors in a manner such that at most two detector

An accurate and reliable device for controlling the position of a first body, of which the devices forms part, relative to a second body is described. The edge of the image of the second body is periodically moved over a row of radiation-sensitive detectors in a manner such that at most two detectors receive modulated radiation.

대표청구항 ▼

A device providing position information of a first body relative to the position of a second body, said device forming a part of the first body and comprising, a radiation sensitive detector system including a plurality of radiation sensitive detectors arranged in a row, a mirror pivotally mounted f

A device providing position information of a first body relative to the position of a second body, said device forming a part of the first body and comprising, a radiation sensitive detector system including a plurality of radiation sensitive detectors arranged in a row, a mirror pivotally mounted for periodic oscillation about an axis at a constant amplitude and frequency and located to receive radiation energy from the second body, an objective system positioned in the path of the radiation energy reflected by the mirror for forming a periodically moving radiation image of the second body on a part of the radiation sensitive detector system, and an electronic circuit for processing a detector signal derived by the radiation sensitive detector system in response to said radiation image thereby to produce a position indication, said row of radiation sensitive detectors being aligned in a direction parallel to the direction of periodic movement of the radiation image and with the detector dimensions, the spacing between detectors and the oscillation amplitude of the mirror being related such that the radiation image of the second body is oscillated over a maximum of two radiation detectors.