| 摘要 |
PROBLEM TO BE SOLVED: To provide a position detector capable of detecting abnormality such as a flaw and dust.SOLUTION: A position detector comprises: a scale provided in one of a fixed element and a movable element and having a pattern string configured periodically in a moving direction; detection means provided in the other element and including a plurality of detection elements aligned in the moving direction; generation means selectively generating a first signal obtained by combining signals from the plurality of detection elements in a first combination and a second signal obtained by combining the signals in a second combination; output means outputting the signal from the generation means; and switch means switching the generation means over between the generation of the first signal and the generation of the second signal, the first signal being a signal having a periodic value depending on a position of the scale relative to the detection means, and the second signal being a signal having a value independent of the position of the scale relative to the detection means. |
