Patent ID: 9200928
Filing Date: 2015-12-01
Classification: G01D

Abstract:
1. A position detector which detects a position of a movable member relative to a fixed member, the position detector comprising: a signal detector configured to detect multiple periodic signals each indicating a predetermined value for the position of the movable member; a signal processor configured to generate multiple displacement signals based on the multiple periodic signals detected by the signal detector and switch the multiple generated displacement signals in a predetermined cycle to sequentially output the multiple displacement signals; a position calculator configured to calculate the position of the movable member based on a first signal group, the first signal group being the multiple displacement signals sequentially output by the signal processor; and a movement amount calculator configured to calculate a movement amount of the movable member within the predetermined cycle, wherein: the first signal group contains a second signal group formed by obtaining the same displacement signal at different times; the movement amount calculator calculates the movement amount of the movable member within the predetermined cycle by using the second signal group; and the position calculator calculates the position of the movable member based on the first signal group and the movement amount.