Rotary Interferometer
First Claim
1. An apparatus for measuring an angular displacement of an object interferometrically, comprising:
- means for generating a laser beam; and
means for splitting the laser beam into a reference beam and a measuring beam, wherein the reference beam is directed at a stationary reference retroreflector and then a phase shift detector, and wherein the measuring beam is directed at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when a length of a path of the measuring beam changes when the rotatable reflective surface is displaced.
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Accused Products
Abstract
An angular displacement of an object is measured interferometrically by splitting a laser beam into a reference beam and a measuring beam. The reference beam is directed at a stationary reference retroreflector and then a phase shift detector. The measuring beam is directed at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when the length of the path of the measuring beam changes when the rotatable reflective surface is displaced.
12 Citations
14 Claims
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1. An apparatus for measuring an angular displacement of an object interferometrically, comprising:
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means for generating a laser beam; and means for splitting the laser beam into a reference beam and a measuring beam, wherein the reference beam is directed at a stationary reference retroreflector and then a phase shift detector, and wherein the measuring beam is directed at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when a length of a path of the measuring beam changes when the rotatable reflective surface is displaced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for measuring an angular displacement of an object interferometrically, comprising:
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means for generating a laser beam; and means for splitting the laser beam into a reference beam and a measuring beam, wherein the reference beam is directed at a stationary reference retroreflector and then a phase shift detector, and wherein the measuring beam is directed at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to a stationary planar reflecting surface and then back to the rotatable reflective surface and then back to a stationary retroreflector and then back to the rotatable surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when a length of a path of the measuring beam changes when the rotatable reflective surface is displaced.
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13. A method for measuring an angular displacement of an object interferometrically, comprising the steps of:
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generating a laser beam; directing the laser beam at a beam splitter to produce a reference beam and a measuring beam; directing the reference beam at a stationary reference retroreflector and then a phase shift detector; and directing the measuring beam at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when the length of the path of the measuring beam changes when the rotatable reflective surface is displaced.
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14. A method for measuring an angular displacement of an object interferometrically, comprising the steps of:
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generating a laser beam; directing the laser beam at a beam splitter to produce a reference beam and a measuring beam; directing the reference beam at a stationary reference retroreflector and then a phase shift detector; and directing the measuring beam at a rotatable reflective surface of the object and then a stationary measuring retroreflector and then back to the rotatable reflective surface and then to a stationary measuring planar reflector and then back to the rotatable reflective surface and then back to the stationary measuring retroreflector and then back to the rotatable reflective surface and then to the phase shift detector such that the phase shift detector measures an angular displacement of the rotatable reflective surface when the length of the path of the measuring beam changes when the rotatable reflective surface is displaced.
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Specification