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US 12,510,348 B2Granted
Acquiring apparatus, acquiring method, and optical system manufacturing method
AssigneeCanon Kabushiki Kaisha
InventorTomohiro Sugimoto
Life of this patent
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Abstract
An acquiring apparatus includes a first light source, a measurement optical system, an image sensor, an adjusting unit, an interferometer, and a calculating unit configured to calculate a distance between adjacent target surfaces among the plurality of target surfaces based on an interference signal. The index surface, a surface containing the first point, a surface containing the second point, and the light receiving surface have a conjugate relationship with each other with respect to the measurement optical system.
Claims10
An acquiring apparatus comprising:
- a first light source configured to illuminate a chart including an index surface on which an index is provided;
- a measurement optical system including an objective lens and configured to cause index light emitted from the chart to enter a target optical system;
- an image sensor configured to receive the index light reflected by a plurality of target surfaces in the target optical system via the measurement optical system;
- an adjusting unit configured to adjust a relative position between the objective lens and the target optical system so as to image the chart by the index light at a reference position on a light receiving surface of the image sensor;
- an interferometer including a second light source, and configured to divide light from the second light source into target light and reference light, and to acquire an interference signal by causing the reference light and the target light that has been emitted from a first point, reflected on the plurality of target surfaces, and incident on a second point via the measurement optical system to interfere with each other;
- and
- a calculating unit configured to calculate a distance between adjacent target surfaces among the plurality of target surfaces based on the interference signal,
- wherein the index surface, a surface containing the first point, a surface containing the second point, and the light receiving surface have a conjugate relationship with each other with respect to the measurement optical system.
5 more elements
An acquiring method comprising the steps of:
- illuminating using a first light source a chart including an index surface on which an index is provided;
- causing index light emitted from the chart to enter a target optical system, and receiving, on an image sensor, the index light reflected by a plurality of target surfaces in the target optical system via a measurement optical system;
- adjusting a relative position between an objective lens and the target optical system so as to form an image of the chart by the index light at a reference position on a light receiving surface of the image sensor;
- dividing light from a second light source into target light and reference light, and acquiring an interference signal by causing the reference light and the target light that has been emitted from a first point, reflected on the plurality of target surfaces, and incident on a second point via the measurement optical system to interfere with each other;
- and
- calculating a distance between adjacent target surfaces among the plurality of target surfaces based on the interference signal, and,
- wherein the adjusting step performs an adjustment while the index surface, a surface containing the first point, a surface containing the second point, and the light receiving surface have a conjugate relationship with each other with respect to the measurement optical system.
4 more elements
Dependencies are inferred from the claim text.