Interferometric position sensor

An interferometric position sensor comprises a light source 110, a beam splitter 134 and a detector array 170. The beam splitter splits light between two paths and an interference pattern 180 is formed based on a difference in length between the two paths. At least one of the paths is dependent on t...

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Bibliographic Details
Main Authors Christopher Ralph Carter, Ross Matthew Williams
Format Patent
LanguageEnglish
Published 09.05.2018
Subjects
MEASURING
MEASURING ANGLES
MEASURING AREAS
MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS
PHYSICS
TESTING
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Summary:An interferometric position sensor comprises a light source 110, a beam splitter 134 and a detector array 170. The beam splitter splits light between two paths and an interference pattern 180 is formed based on a difference in length between the two paths. At least one of the paths is dependent on the position of an object 10 such that changes in the interference pattern are related to changes in the position of the object. The beam splitter is formed as a beam splitting surface of a prism, the other surface 136 of the prism being fully reflecting. This surface 136 fulfils the function of a reference mirror in a conventional interferometer. The interferometric position sensor therefore does not require a reference mirror, avoiding errors caused by a changing distance between the beam splitter and the reference mirror. The object 10 for which position is sensed may have an attached retroreflector 150.
Bibliography:Application Number: GB20160018796