| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect positions even if an optical scale expands or contracts due to the temperature change.SOLUTION: A position detector includes: first optical position detection means 103 for generating a plurality of first detection signals upon reception of light from a plurality of periodic patterns when moving relative to an optical scale 101 along with the movement of a movable member 102; second non-optical position detection means 108 for generating a second detection signal that changes along with the movement of the movable member; and calculation means 106 for generating an absolute position signal representing the absolute position of the movable member by generating a first position signal using the first detection signals, generating a second position signal with resolution different from that of the first position signal with the use of the second detection signal, and calculating to combine the first position signal and the second position signal. Correction means 150 calculates the correction gain in accordance with the ratio between the first position signal and the second position signal to generate the correction absolute position signal obtained by correcting the absolute position signal with the correction gain.SELECTED DRAWING: Figure 1 |
