| 摘要 |
PROBLEM TO BE SOLVED: To provide a length measuring device which removes errors caused by the attitude error of a moving base by obtaining the reference position in a prescribed direction of the moving base based on multiple detection values detected in a prescribed range near the prescribed position. SOLUTION: A lower plate 10X of a stage device 10 of a moving base is movable in the lateral direction (X-direction), an upper plate 10Y is supported and guided by the lower plate 10X and is movable in the longitudinal direction (Y-direction), First and second position detecting means (linear encoders) 22, 24 for obtaining the position in the prescribed direction (Y-direction) of the moving base are provided separated at a distance by the prescribed distance in the direction perpendicular to the moving direction. A third position detecting means (linear encoder) for obtaining the position in another direction (X- direction) of the moving base is provided. The reference position in the prescribed direction of the moving base is obtained, based on multiple detection values detected by the first and second position detecting means in the prescribed range near the prescribed position.
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