Compact Littrow Encoder
First Claim
1. An apparatus comprising:
- a first interferometer;
a second interferometer; and
a beam splitter assembly that splits a first instrument light beam into first and second interferometer input beams and directs said first and second interferometer light beams into said first and second interferometers, respectively,wherein each interferometer generates a measurement beam and a reference beam from said input beam to that interferometer and directs said measurement beam toward a surface from which said measurement beam is diffracted, said measurement beam from said first interferometer striking said surface at an angle relative to the normal to that surface that is the negative of the angle at which said measurement beam from the other of said interferometers strikes that surface and wherein each interferometer comprises an intensity detector that generates a signal related to an intensity of light in a combined light beam comprising said reference and measurement beams from that interferometer.
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Accused Products
Abstract
A Littrow encoder is disclosed. The encoder includes first and second interferometers and a beam splitter assembly that splits a first instrument light beam into first and second interferometer input beams and directs these beams into the first and second interferometers, respectively. Each interferometer generates a measurement beam and a reference beam and directs the measurement beam toward a grating on a surface from which the measurement beam is diffracted, the measurement beam from the first interferometer striking the surface at a Littrow angle that is the negative of the angle at which the measurement beam from the second interferometers strikes that surface. Each interferometer includes at least one intensity detector that generates a signal related to an intensity of light in a combined light beam that includes the reference and measurement beams from that interferometer.
54 Citations
16 Claims
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1. An apparatus comprising:
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a first interferometer; a second interferometer; and a beam splitter assembly that splits a first instrument light beam into first and second interferometer input beams and directs said first and second interferometer light beams into said first and second interferometers, respectively, wherein each interferometer generates a measurement beam and a reference beam from said input beam to that interferometer and directs said measurement beam toward a surface from which said measurement beam is diffracted, said measurement beam from said first interferometer striking said surface at an angle relative to the normal to that surface that is the negative of the angle at which said measurement beam from the other of said interferometers strikes that surface and wherein each interferometer comprises an intensity detector that generates a signal related to an intensity of light in a combined light beam comprising said reference and measurement beams from that interferometer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification