Abstract: A digital micrometer includes a main-body frame, a spindle, a thimble part, and a displacement detector that detects displacement of the spindle. The main-body frame includes a U-shaped frame part, and a spindle holding part provided on the other end side of the U-shaped frame part and having a length in a direction away from an anvil. The spindle is held by a spindle holding part, provided to be movable forward and backward in an axial direction with respect to the anvil, and includes a contactor on one end face. The main-body frame and the spindle are formed of a non-magnetic material.

Abstract: A method that corrects an error in positioning in a positioning mechanism by using a measurable length value measured by a laser interferometer and a measured value for spatial coordinates measured by the positioning mechanism. The method includes a measurement step in which a retroreflector affixed to a displacer is displaced to a plurality of measurement points, and the measured length value and the measured value at each of the measurement points is acquired; and a parameter calculation step in which a correction parameter is calculated based on the measured value, the measured length value, and the coordinates of a rotation center of the tracking-type laser interferometer. A first correction constant is applied to the measured length value for each measurement line, and a second correction constant different from the first correction constant is applied to the coordinates of the rotation center of the interferometer for each measurement line.

Abstract: 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.

Abstract: There is provided a digital micrometer suitable for measuring an object to be measured that is a strong magnet. A digital micrometer includes a main-body frame, a spindle, a thimble part, and a displacement detector that detects displacement of the spindle. The main-body frame includes an U-shaped frame part, and a spindle holding part provided on the other end side of the U-shaped frame part and having a length in a direction away from an anvil. The spindle is held by a spindle holding part, provided to be movable forward and backward in an axial direction with respect to the anvil, and includes a contactor on one end face. The main-body frame and the spindle are formed of a non-magnetic material.

Abstract: A method that corrects an error in positioning in a positioning mechanism by using a measurable length value measured by a laser interferometer and a measured value for spatial coordinates measured by the positioning mechanism. The method includes a measurement step in which a retroreflector affixed to a displacer is displaced to a plurality of measurement points, and the measured length value and the measured value at each of the measurement points is acquired; and a parameter calculation step in which a correction parameter is calculated based on the measured value, the measured length value, and the coordinates of a rotation center of the tracking-type laser interferometer. A first correction constant is applied to the measured length value for each measurement line, and a second correction constant different from the first correction constant is applied to the coordinates of the rotation center of the interferometer for each measurement line.

Abstract: 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.

Abstract: A laser tracking interferometer has a carriage provided with a first displacement gauge outputting a displacement signal associated with a relative displacement from a reference sphere; a second retroreflector provided to the carriage; a laser interferometer provided to the carriage and outputting a displacement signal associated with a relative displacement between the first retroreflector and the second retroreflector; and a data processor calculating a displacement of the first retroreflector with reference to the reference sphere based on the displacement signal output from the first displacement gauge and the displacement signal output from the laser interferometer.

Abstract: A laser tracking interferometer has a carriage provided with a first displacement gauge outputting a displacement signal associated with a relative displacement from a reference sphere; a second retroreflector provided to the carriage; a laser interferometer provided to the carriage and outputting a displacement signal associated with a relative displacement between the first retroreflector and the second retroreflector; and a data processor calculating a displacement of the first retroreflector with reference to the reference sphere based on the displacement signal output from the first displacement gauge and the displacement signal output from the laser interferometer.