Interferometer
AssigneeCanon Kabushiki Kaisha
InventorsKo ISHIZUKA, Ryo SASAKI, Koichi MASEGI
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Abstract
An interferometer measures a displacement of an object to be measured by observing a fluctuation in intensity of interfering light generated by dividing light emitted from a light source into two light beams and overlaying the two light beams. The interferometer includes: a light-receiving unit including a light-receiving area including a plurality of partial areas and configured to detect the interfering light in each of the plurality of partial areas; and a processing unit configured to calculate a value of an index indicating uniformity of a phase distribution of the interfering light in the light-receiving area by using a detection result in each of the partial areas.
Claims7
An interferometer which measures a displacement of an object to be measured by observing a fluctuation in intensity of interfering light generated by dividing light emitted from a light source into two light beams and overlaying the two light beams, the interferometer comprising:
- a light-receiving unit including a light-receiving area including a plurality of partial areas and configured to detect the interfering light in each of the plurality of partial areas;
- and
- a processing unit configured to calculate a value of an index indicating uniformity of a phase distribution of the interfering light in the light-receiving area by using a detection result in each of the partial areas.
An interferometer which measures a displacement of an object to be measured by observing a fluctuation in intensity of interfering light generated by dividing light emitted from a light source into two light beams and overlaying the two light beams, the interferometer comprising
- a head unit having a rotational angle and a position which are configured to be changed,
- said head unit comprising a light-receiving unit including a light-receiving area including a plurality of partial areas and configured to detect the interfering light in each of the plurality of partial areas,
- wherein a phase shift of the interfering light detected in each of the partial areas is changed by changing the rotational angle and position of said head unit.
Dependencies are inferred from the claim text.