A spatial accuracy correction apparatus performs a spatial accuracy correction of a positioner displacing a displacer to a predetermined set of spatial coordinates using a measurable length value measured by an interferometer and a measurable value of the set of spatial coordinates of the displacement body that is measured by the positioner. The measured length value and the measured value for each measurement point are acquired by displacing the displacement body to a plurality of measurement points in order, one or more repeated measurements are conducted for at least one of the plurality of measurement points being measured after conducting measurement of the measured length value and the measured value for each of the plurality of measurement points, and the plurality of points are measured again when a repeat error of the measured length value is equal to or greater than a threshold value.

The present invention relates to an arrangement and a method for single-shot interferometry which can be used for detecting distance, profile, shape, undulation, roughness or the optical path length in or on optically rough or smooth objects or else for optical coherence tomography (OCT). The arrangement comprises a light source, an interferometer, in which an end reflector is arranged in the reference beam path, and also a detector for detecting an interferogram. In the reference beam path of the interferometer, the end reflector can be embodied with three plane reflecting surfaces as a prism mirror or air mirror assembly in order to generate between reference and object beams a lateral shear of magnitude delta_q for obtaining a spatial interferogram. The embodiment of said assembly with regard to the angles and the arrangement of the reflecting surfaces makes possible a large aperture angle for a high numerical aperture. In the method, in the reference beam path it is possible to carry out a reduction of the aperture angle of the reference beam using beam-limiting means in order to achieve an optimum adaptation to the geometrically given aperture angle of the end reflector in the reference beam path, which is designed to be smaller than the aperture angle in the object beam path. The end reflector in the reference beam path can also be used as part of a second interferometer for high-resolution measurement of the displacement of the arrangement for single-shot interferometry, wherein said displacement serves for focusing. The end reflector is embodied as a triple reflection arrangement (e.g. a prism arrangement) having three reflecting surfaces. The triple reflection arrangement can have an M- or W-beam path, a non-intersecting zigzag beam path or an intersecting (zigzag) beam path.

A stage device includes a stage capable of moving in a first direction and a second direction orthogonal to each other, a scale arranged in the stage so as to extend in the first direction, an optical assembly arranged so as to face the scale in at least a part of a movable range of the stage and extending in the second direction, and an interferometer configured to transmit measurement light and reference light to the optical assembly, and receive the measurement light and the reference light returning from the optical assembly. The optical assembly is configured to apply the measurement light from the interferometer to the scale, and return the measurement light returning from the scale and the reference light to the interferometer.

An interferometric position sensor for sensing the position of an object is disclosed. The position sensor comprises a light source arranged to emit light, a beam splitter, and a detector array. The beam splitter is arranged to split the light between first and second optical paths, which are configured such that the split light is recombined so as to form an optical interference pattern dependent on the difference between the optical path lengths of the first and second optical paths. The detector array is arranged to measure the intensity of at least a part of the optical interference pattern. At least one of the first and second optical path lengths is arranged to be dependent on the position of the object, such that changes in the optical interference pattern can be related to changes in the position of the object.

The present invention relates to an arrangement and a method for single-shot interferometry which can be used for detecting distance, profile, shape, undulation, roughness or the optical path length in or on optically rough or smooth objects or else for optical coherence tomography (OCT). The arrangement comprises a light source, an interferometer, in which an end reflector is arranged in the reference beam path, and also a detector for detecting an interferogram. In the reference beam path of the interferometer, the end reflector can be embodied with three plane reflecting surfaces as a prism mirror or air mirror assembly in order to generate between reference and object beams a lateral shear of magnitude delta_q for obtaining a spatial interferogram. The embodiment of said assembly with regard to the angles and the arrangement of the reflecting surfaces makes possible a large aperture angle for a high numerical aperture. In the method, in the reference beam path it is possible to carry out a reduction of the aperture angle of the reference beam using beam-limiting means in order to achieve an optimum adaptation to the geometrically given aperture angle of the end reflector in the reference beam path, which is designed to be smaller than the aperture angle in the object beam path. The end reflector in the reference beam path can also be used as part of a second interferometer for high-resolution measurement of the displacement of the arrangement for single-shot interferometry, wherein said displacement serves for focusing. The end reflector is embodied as a triple reflection arrangement (e.g. a prism arrangement) having three reflecting surfaces. The triple reflection arrangement can have an M- or W-beam path, a non-intersecting zigzag beam path or an intersecting (zigzag) beam path.

Provided is a position detection method including splitting detection light into first and second light, the first light being incident on a returning optical path, a portion of the first light being transmitted through a beam splitter and a remaining portion of the first light being reflected by the beam splitter to reach the beam splitter through a movable mirror every time the first light reaches the beam splitter through the movable mirror, combining the first light transmitted though the beam splitter and the second light to generate multiple interference light, extracting a second interference light signal having a wavelength of 1/p (p is a natural number) of a wavelength of detection light from a first interference light signal of the multiple interference light, and calculating a position of the movable portion in a predetermined direction based on the second interference light signal.

An interferometric position sensor for sensing the position of an object is disclosed. The position sensor comprises a light source arranged to emit light, a beam splitter, and a detector array. The beam splitter is arranged to split the light between first and second optical paths, which are configured such that the split light is recombined so as to form an optical interference pattern dependent on the difference between the optical path lengths of the first and second optical paths. The detector array is arranged to measure the intensity of at least a part of the optical interference pattern. At least one of the first and second optical path lengths is arranged to be dependent on the position of the object, such that changes in the optical interference pattern can be related to changes in the position of the object.

A spatial accuracy correction apparatus performs a spatial accuracy correction of a positioner displacing a displacer to a predetermined set of spatial coordinates using a measurable length value measured by an interferometer and a measurable value of the set of spatial coordinates of the displacement body that is measured by the positioner. The measured length value and the measured value for each measurement point are acquired by displacing the displacement body to a plurality of measurement points in order, one or more repeated measurements are conducted for at least one of the plurality of measurement points being measured after conducting measurement of the measured length value and the measured value for each of the plurality of measurement points, and the plurality of points are measured again when a repeat error of the measured length value is equal to or greater than a threshold value.

What is proposed is a device (1) for optically measuring an object, comprising an interferometer (2) having a measurement arm (21), wherein the measurement arm (21) is provided for optically measuring the object, and comprising a focusing element (3) arranged within the measurement arm (21). According to the invention, the device (1) comprises a first retardation element (4) arranged within the measurement arm (21) and downstream of the focusing element (3), wherein the first retardation element (4) has a movable displacement element (42), by means of which the optical path length of the beam path of the measurement arm (21) is variable.

Provided is a position detection method including splitting detection light into first and second light, the first light being incident on a returning optical path, a portion of the first light being transmitted through a beam splitter and a remaining portion of the first light being reflected by the beam splitter to reach the beam splitter through a movable mirror every time the first light reaches the beam splitter through the movable mirror, combining the first light transmitted though the beam splitter and the second light to generate multiple interference light, extracting a second interference light signal having a wavelength of 1/p (p is a natural number) of a wavelength of detection light from a first interference light signal of the multiple interference light, and calculating a position of the movable portion in a predetermined direction based on the second interference light signal.